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Farnell PDF
PIC18FXX2 Data Sheet - Microchip - Farnell Element 14
PIC18FXX2 Data Sheet - Microchip - Farnell Element 14
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Farnell Element 14 :
See the trailer for the next exciting episode of The Ben Heck show. Check back on Friday to be among the first to see the exclusive full show on element…
Connect your Raspberry Pi to a breadboard, download some code and create a push-button audio play project.
Puce électronique / Microchip :
Sans fil - Wireless :
Texas instrument :
Ordinateurs :
Logiciels :
Tutoriels :
Autres documentations :
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© 2006 Microchip Technology Inc. DS39564C
PIC18FXX2
Data Sheet
High-Performance, Enhanced Flash
Microcontrollers with 10-Bit A/DDS39564C-page ii © 2006 Microchip Technology Inc.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE, PowerSmart, rfPIC and SmartShunt are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,
SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, ECAN,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, Linear Active
Thermistor, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit,
PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal,
PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB,
rfPICDEM, Select Mode, Smart Serial, SmartTel, Total
Endurance, UNI/O, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2006, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona, Gresham, Oregon and Mountain View, California. The
Company’s quality system processes and procedures are for its
PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, nonvolatile memory and analog
products. In addition, Microchip’s quality system for the design and
manufacture of development systems is ISO 9001:2000 certified.© 2006 Microchip Technology Inc. DS39564C-page 1
PIC18FXX2
High Performance RISC CPU:
• C compiler optimized architecture/instruction set
- Source code compatible with the PIC16 and
PIC17 instruction sets
• Linear program memory addressing to 32 Kbytes
• Linear data memory addressing to 1.5 Kbytes
• Up to 10 MIPs operation:
- DC - 40 MHz osc./clock input
- 4 MHz - 10 MHz osc./clock input with PLL active
• 16-bit wide instructions, 8-bit wide data path
• Priority levels for interrupts
• 8 x 8 Single Cycle Hardware Multiplier
Peripheral Features:
• High current sink/source 25 mA/25 mA
• Three external interrupt pins
• Timer0 module: 8-bit/16-bit timer/counter with
8-bit programmable prescaler
• Timer1 module: 16-bit timer/counter
• Timer2 module: 8-bit timer/counter with 8-bit
period register (time-base for PWM)
• Timer3 module: 16-bit timer/counter
• Secondary oscillator clock option - Timer1/Timer3
• Two Capture/Compare/PWM (CCP) modules.
CCP pins that can be configured as:
- Capture input: capture is 16-bit,
max. resolution 6.25 ns (TCY/16)
- Compare is 16-bit, max. resolution 100 ns (TCY)
- PWM output: PWM resolution is 1- to 10-bit,
max. PWM freq. @: 8-bit resolution = 156 kHz
10-bit resolution = 39 kHz
• Master Synchronous Serial Port (MSSP) module,
Two modes of operation:
- 3-wire SPI™ (supports all 4 SPI modes)
- I2C™ Master and Slave mode
Peripheral Features (Continued):
• Addressable USART module:
- Supports RS-485 and RS-232
• Parallel Slave Port (PSP) module
Analog Features:
• Compatible 10-bit Analog-to-Digital Converter
module (A/D) with:
- Fast sampling rate
- Conversion available during SLEEP
- Linearity ≤ 1 LSb
• Programmable Low Voltage Detection (PLVD)
- Supports interrupt on-Low Voltage Detection
• Programmable Brown-out Reset (BOR)
Special Microcontroller Features:
• 100,000 erase/write cycle Enhanced FLASH
program memory typical
• 1,000,000 erase/write cycle Data EEPROM
memory
• FLASH/Data EEPROM Retention: > 40 years
• Self-reprogrammable under software control
• Power-on Reset (POR), Power-up Timer (PWRT)
and Oscillator Start-up Timer (OST)
• Watchdog Timer (WDT) with its own On-Chip RC
Oscillator for reliable operation
• Programmable code protection
• Power saving SLEEP mode
• Selectable oscillator options including:
- 4X Phase Lock Loop (of primary oscillator)
- Secondary Oscillator (32 kHz) clock input
• Single supply 5V In-Circuit Serial Programming™
(ICSP™) via two pins
• In-Circuit Debug (ICD) via two pins
CMOS Technology:
• Low power, high speed FLASH/EEPROM
technology
• Fully static design
• Wide operating voltage range (2.0V to 5.5V)
• Industrial and Extended temperature ranges
• Low power consumption:
- < 1.6 mA typical @ 5V, 4 MHz
- 25 μA typical @ 3V, 32 kHz
- < 0.2 μA typical standby current
Device
On-Chip Program
Memory On-Chip
RAM
(bytes)
Data
EEPROM
FLASH (bytes)
(bytes)
# Single Word
Instructions
PIC18F242 16K 8192 768 256
PIC18F252 32K 16384 1536 256
PIC18F442 16K 8192 768 256
PIC18F452 32K 16384 1536 256
28/40-pin High Performance, Enhanced FLASH
Microcontrollers with 10-Bit A/DPIC18FXX2
DS39564C-page 2 © 2006 Microchip Technology Inc.
Pin Diagrams
10
11
12
13
14
15
16
1718
19
20
21
22
23
24
25
26
44
8
7
6
5
4
3
2
1
27
28
29
30
31
32
33
34
35
36
37
38
39
43
42
41
40
9
PIC18F442
RA4/T0CKI
RA5/AN4/SS/LVDIN
RE0/RD/AN5
OSC2/CLKO/RA6
NC
RE1/WR/AN6
RE2/CS/AN7
VDD
OSC1/CLKI
RB3/CCP2* RB2/INT2
RB1/INT1
RB0/INT0
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
MCLR/VPP
NC
RB7/PGD
RB6/PGC
RB5/PGM
RB4
NC
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
NC
*
10
11
2
3
4
5
6
1
12
13
14
15
18
19
20
21
22
38
8
7
44
43
42
41
40
39
16
17
29
30
31
32
33
23
24
25
26
27
28
36
35
34
9
PIC18F44237
RA3/AN3/VREF+
RA2/AN2/VREFMCLR
RA0/AN0 RA1/AN1 /VPP
NC
NC
RB4
RB5/PGM
RB6/PGC
RB7/PGD
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1
RC1/T1OSI/CCP2*
NC
NC
RC0/T1OSO/T1CKI
OSC2/CLKO/RA6
OSC1/CLKI
VSS
VDD
RE2/AN7/CS
RE1/AN6/WR
RE0/AN5/RD
RA5/AN4/SS/LVDIN
RA4/T0CKI
RC7/RX/DT
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
VSS
VDD
RB0/INT0
RB1/INT1
RB2/INT2
RB3/CCP2*
PLCC
TQFP
* RB3 is the alternate pin for the CCP2 pin multiplexing.
VSS
RC0/T1OSO/T1CKI
PIC18F452
PIC18F452© 2006 Microchip Technology Inc. DS39564C-page 3
PIC18FXX2
Pin Diagrams (Cont.’d)
RB7/PGD
RB6/PGC
RB5/PGM
RB4
RB3/CCP2*
RB2/INT2
RB1/INT1
RB0/INT0
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/SS/LVDIN
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKI
OSC2/CLKO/RA6
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2*
RC2/CCP1
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
PIC18F442
10
PIC18F242
11
2
3
4
5
6
1
8
7
9
12
13
14 15
16
17
18
19
20
23
24
25
26
27
28
22
21
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/SS/LVDIN
VSS
OSC1/CLKI
OSC2/CLKO/RA6
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2*
RC2/CCP1
RC3/SCK/SCL
RB7/PGD
RB6/PGC
RB5/PGM
RB4
RB3/CCP2*
RB2/INT2
RB1/INT1
RB0/INT0
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
* RB3 is the alternate pin for the CCP2 pin multiplexing.
DIP
DIP, SOIC
Note: Pin compatible with 40-pin PIC16C7X devices.
PIC18F452
PIC18F252PIC18FXX2
DS39564C-page 4 © 2006 Microchip Technology Inc.
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 7
2.0 Oscillator Configurations ............................................................................................................................................................ 17
3.0 Reset .......................................................................................................................................................................................... 25
4.0 Memory Organization ................................................................................................................................................................. 35
5.0 FLASH Program Memory ........................................................................................................................................................... 55
6.0 Data EEPROM Memory ............................................................................................................................................................. 65
7.0 8 X 8 Hardware Multiplier ........................................................................................................................................................... 71
8.0 Interrupts .................................................................................................................................................................................... 73
9.0 I/O Ports ..................................................................................................................................................................................... 87
10.0 Timer0 Module ......................................................................................................................................................................... 103
11.0 Timer1 Module ......................................................................................................................................................................... 107
12.0 Timer2 Module ......................................................................................................................................................................... 111
13.0 Timer3 Module ......................................................................................................................................................................... 113
14.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 117
15.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 125
16.0 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART).............................................................. 165
17.0 Compatible 10-bit Analog-to-Digital Converter (A/D) Module................................................................................................... 181
18.0 Low Voltage Detect .................................................................................................................................................................. 189
19.0 Special Features of the CPU.................................................................................................................................................... 195
20.0 Instruction Set Summary .......................................................................................................................................................... 211
21.0 Development Support............................................................................................................................................................... 253
22.0 Electrical Characteristics .......................................................................................................................................................... 259
23.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 289
24.0 Packaging Information.............................................................................................................................................................. 305
Appendix A: Revision History............................................................................................................................................................ 313
Appendix B: Device Differences........................................................................................................................................................ 313
Appendix C: Conversion Considerations........................................................................................................................................... 314
Appendix D: Migration from Baseline to Enhanced Devices ............................................................................................................. 314
Appendix E: Migration from Mid-range to Enhanced Devices........................................................................................................... 315
Appendix F: Migration from High-end to Enhanced Devices ............................................................................................................ 315
Index .................................................................................................................................................................................................. 317
On-Line Support................................................................................................................................................................................. 327
Reader Response .............................................................................................................................................................................. 328
PIC18FXX2 Product Identification System......................................................................................................................................... 329© 2006 Microchip Technology Inc. DS39564C-page 5
PIC18FXX2
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
E-mail at docerrors@microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We
welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
using.
Customer Notification System
Register on our web site at www.microchip.com to receive the most current information on all of our products.PIC18FXX2
DS39564C-page 6 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 7
PIC18FXX2
1.0 DEVICE OVERVIEW
This document contains device specific information for
the following devices:
These devices come in 28-pin and 40/44-pin packages.
The 28-pin devices do not have a Parallel Slave Port
(PSP) implemented and the number of Analog-toDigital
(A/D) converter input channels is reduced to 5.
An overview of features is shown in Table 1-1.
The following two figures are device block diagrams
sorted by pin count: 28-pin for Figure 1-1 and 40/44-pin
for Figure 1-2. The 28-pin and 40/44-pin pinouts are
listed in Table 1-2 and Table 1-3, respectively.
TABLE 1-1: DEVICE FEATURES
• PIC18F242 • PIC18F442
• PIC18F252 • PIC18F452
Features PIC18F242 PIC18F252 PIC18F442 PIC18F452
Operating Frequency DC - 40 MHz DC - 40 MHz DC - 40 MHz DC - 40 MHz
Program Memory (Bytes) 16K 32K 16K 32K
Program Memory (Instructions) 8192 16384 8192 16384
Data Memory (Bytes) 768 1536 768 1536
Data EEPROM Memory (Bytes) 256 256 256 256
Interrupt Sources 17 17 18 18
I/O Ports Ports A, B, C Ports A, B, C Ports A, B, C, D, E Ports A, B, C, D, E
Timers 4 4 4 4
Capture/Compare/PWM Modules 2 2 2 2
Serial Communications
MSSP,
Addressable
USART
MSSP,
Addressable
USART
MSSP,
Addressable
USART
MSSP,
Addressable
USART
Parallel Communications — — PSP PSP
10-bit Analog-to-Digital Module 5 input channels 5 input channels 8 input channels 8 input channels
RESETS (and Delays)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST)
Programmable Low Voltage
Detect
Yes Yes Yes Yes
Programmable Brown-out Reset Yes Yes Yes Yes
Instruction Set 75 Instructions 75 Instructions 75 Instructions 75 Instructions
Packages 28-pin DIP
28-pin SOIC
28-pin DIP
28-pin SOIC
40-pin DIP
44-pin PLCC
44-pin TQFP
40-pin DIP
44-pin PLCC
44-pin TQFPPIC18FXX2
DS39564C-page 8 © 2006 Microchip Technology Inc.
FIGURE 1-1: PIC18F2X2 BLOCK DIAGRAM
Instruction
Decode &
Control
PORTA
PORTB
PORTC
RA4/T0CKI
RA5/AN4/SS/LVDIN
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
Note 1: Optional multiplexing of CCP2 input/output with RB3 is enabled by selection of configuration bit.
2: The high order bits of the Direct Address for the RAM are from the BSR register (except for the MOVFF instruction).
3: Many of the general purpose I/O pins are multiplexed with one or more peripheral module functions. The multiplexing combinations
are device dependent.
Addressable
CCP1 Synchronous
Timer0 Timer1 Timer2
Serial Port
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
A/D Converter
Data Latch
Data RAM
Address Latch
Address<12>
12(2)
BSR FSR0
FSR1
FSR2
4 12 4
PCH PCL
PCLATH
8
31 Level Stack
Program Counter
PRODH PRODL
8 x 8 Multiply
WREG
8
BIT OP
8 8
ALU<8>
8
Address Latch
Program Memory
(up to 2 Mbytes)
Data Latch
21
21
16
8
8
8
inc/dec logic
21
8
Data Bus<8>
8
Instruction
12
3
ROM Latch
Timer3
CCP2
Bank0, F
PCLATU
PCU
RA6
USART
Master
8
Register
Table Latch
Table Pointer
inc/dec
Decode logic
RB0/INT0
RB4
RB1/INT1
RB2/INT2
RB3/CCP2(1)
RB5/PGM
RB6/PCG
RB7/PGD
Data EEPROM
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
OSC1/CLKI
OSC2/CLKO
MCLR
VDD, VSS
Brown-out
Reset
Timing
Generation
4X PLL
T1OSCI
T1OSCO
Precision
Reference
Voltage
Low Voltage
Programming
In-Circuit
Debugger© 2006 Microchip Technology Inc. DS39564C-page 9
PIC18FXX2
FIGURE 1-2: PIC18F4X2 BLOCK DIAGRAM
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode &
Control
OSC1/CLKI
OSC2/CLKO
MCLR
VDD, VSS
PORTA
PORTB
PORTC
RA4/T0CKI
RA5/AN4/SS/LVDIN
RB0/INT0
RB4
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
Brown-out
Reset
Note 1: Optional multiplexing of CCP2 input/output with RB3 is enabled by selection of configuration bit.
2: The high order bits of the Direct Address for the RAM are from the BSR register (except for the MOVFF instruction).
3: Many of the general purpose I/O pins are multiplexed with one or more peripheral module functions. The multiplexing combinations
are device dependent.
Addressable CCP1
Master
Timer0 Timer1 Timer2
Serial Port
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
Parallel Slave Port
Timing
Generation
4X PLL
A/D Converter
RB1/INT1
Data Latch
Data RAM
(up to 4K
address reach)
Address Latch
Address<12>
12(2)
BSR FSR0 Bank0, F
FSR1
FSR2
4 12 4
PCH PCL
PCLATH
8
31 Level Stack
Program Counter
PRODH PRODL
8 x 8 Multiply
WREG
8
BIT OP
8 8
ALU<8>
8
Address Latch
Program Memory
(up to 2 Mbytes)
Data Latch
21
21
16
8
8
8
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
Instruction
12
3
ROM Latch
Timer3
PORTD
PORTE
RE0/AN5/RD
RE1/AN6/WR
RE2/AN7/CS
CCP2
RB2/INT2
RB3/CCP2(1)
T1OSCI
T1OSCO
PCLATU
PCU
RA6
Precision
Reference
Voltage
Synchronous USART
Register
8
Table Pointer
inc/dec
logic Decode
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
Low Voltage
Programming
In-Circuit
Debugger
Data EEPROM
RB5/PGM
RB6/PCG
RB7/PGDPIC18FXX2
DS39564C-page 10 © 2006 Microchip Technology Inc.
TABLE 1-2: PIC18F2X2 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP SOIC
MCLR/VPP
MCLR
VPP
1 1
I
I
ST
ST
Master Clear (input) or high voltage ICSP programming
enable pin.
Master Clear (Reset) input. This pin is an active low
RESET to the device.
High voltage ICSP programming enable pin.
NC — — — — These pins should be left unconnected.
OSC1/CLKI
OSC1
CLKI
9 9
I
I
ST
CMOS
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode, CMOS otherwise.
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
OSC2/CLKO/RA6
OSC2
CLKO
RA6
10 10
O
O
I/O
—
—
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or
resonator in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO which has 1/4
the frequency of OSC1, and denotes the instruction
cycle rate.
General Purpose I/O pin.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
AN0
2 2
I/O
I
TTL
Analog
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
3 3
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
RA2/AN2/VREFRA2
AN2
VREF-
4 4
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
RA3/AN3/VREF+
RA3
AN3
VREF+
5 5
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 3.
A/D Reference Voltage (High) input.
RA4/T0CKI
RA4
T0CKI
6 6
I/O
I
ST/OD
ST
Digital I/O. Open drain when configured as output.
Timer0 external clock input.
RA5/AN4/SS/LVDIN
RA5
AN4
SS
LVDIN
7 7
I/O
I
I
I
TTL
Analog
ST
Analog
Digital I/O.
Analog input 4.
SPI Slave Select input.
Low Voltage Detect Input.
RA6 See the OSC2/CLKO/RA6 pin.
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) © 2006 Microchip Technology Inc. DS39564C-page 11
PIC18FXX2
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/INT0
RB0
INT0
21 21
I/O
I
TTL
ST
Digital I/O.
External Interrupt 0.
RB1/INT1
RB1
INT1
22 22
I/O
I
TTL
ST External Interrupt 1.
RB2/INT2
RB2
INT2
23 23
I/O
I
TTL
ST
Digital I/O.
External Interrupt 2.
RB3/CCP2
RB3
CCP2
24 24
I/O
I/O
TTL
ST
Digital I/O.
Capture2 input, Compare2 output, PWM2 output.
RB4 25 25 I/O TTL Digital I/O.
Interrupt-on-change pin.
RB5/PGM
RB5
PGM
26 26
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
Low Voltage ICSP programming enable pin.
RB6/PGC
RB6
PGC
27 27
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming clock pin.
RB7/PGD
RB7
PGD
28 28
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming data pin.
TABLE 1-2: PIC18F2X2 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP SOIC
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) PIC18FXX2
DS39564C-page 12 © 2006 Microchip Technology Inc.
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
RC0
T1OSO
T1CKI
11 11
I/O
O
I
ST
—
ST
Digital I/O.
Timer1 oscillator output.
Timer1/Timer3 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2
12 12
I/O
I
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
RC2/CCP1
RC2
CCP1
13 13
I/O
I/O
ST
ST
Digital I/O.
Capture1 input/Compare1 output/PWM1 output.
RC3/SCK/SCL
RC3
SCK
SCL
14 14
I/O
I/O
I/O
ST
ST
ST
Digital I/O.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C mode
RC4/SDI/SDA
RC4
SDI
SDA
15 15
I/O
I
I/O
ST
ST
ST
Digital I/O.
SPI Data In.
I
2C Data I/O.
RC5/SDO
RC5
SDO
16 16
I/O
O
ST
—
Digital I/O.
SPI Data Out.
RC6/TX/CK
RC6
TX
CK
17 17
I/O
O
I/O
ST
—
ST
Digital I/O.
USART Asynchronous Transmit.
USART Synchronous Clock (see related RX/DT).
RC7/RX/DT
RC7
RX
DT
18 18
I/O
I
I/O
ST
ST
ST
Digital I/O.
USART Asynchronous Receive.
USART Synchronous Data (see related TX/CK).
VSS 8, 19 8, 19 P — Ground reference for logic and I/O pins.
VDD 20 20 P — Positive supply for logic and I/O pins.
TABLE 1-2: PIC18F2X2 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP SOIC
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) © 2006 Microchip Technology Inc. DS39564C-page 13
PIC18FXX2
TABLE 1-3: PIC18F4X2 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP PLCC TQFP
MCLR/VPP
MCLR
VPP
1 2 18
I
I
ST
ST
Master Clear (input) or high voltage ICSP
programming enable pin.
Master Clear (Reset) input. This pin is an active
low RESET to the device.
High voltage ICSP programming enable pin.
NC — — — These pins should be left unconnected.
OSC1/CLKI
OSC1
CLKI
13 14 30
I
I
ST
CMOS
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source
input. ST buffer when configured in RC mode,
CMOS otherwise.
External clock source input. Always associated
with pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
OSC2/CLKO/RA6
OSC2
CLKO
RA6
14 15 31
O
O
I/O
—
—
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal
or resonator in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO,
which has 1/4 the frequency of OSC1 and
denotes the instruction cycle rate.
General Purpose I/O pin.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
AN0
2 3 19
I/O
I
TTL
Analog
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
3 4 20
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
RA2/AN2/VREFRA2
AN2
VREF-
4 5 21
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
RA3/AN3/VREF+
RA3
AN3
VREF+
5 6 22
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 3.
A/D Reference Voltage (High) input.
RA4/T0CKI
RA4
T0CKI
6 7 23
I/O
I
ST/OD
ST
Digital I/O. Open drain when configured as output.
Timer0 external clock input.
RA5/AN4/SS/LVDIN
RA5
AN4
SS
LVDIN
7 8 24
I/O
I
I
I
TTL
Analog
ST
Analog
Digital I/O.
Analog input 4.
SPI Slave Select input.
Low Voltage Detect Input.
RA6 (See the OSC2/CLKO/RA6 pin.)
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) PIC18FXX2
DS39564C-page 14 © 2006 Microchip Technology Inc.
PORTB is a bi-directional I/O port. PORTB can be
software programmed for internal weak pull-ups on all
inputs.
RB0/INT0
RB0
INT0
33 36 8
I/O
I
TTL
ST
Digital I/O.
External Interrupt 0.
RB1/INT1
RB1
INT1
34 37 9
I/O
I
TTL
ST External Interrupt 1.
RB2/INT2
RB2
INT2
35 38 10
I/O
I
TTL
ST
Digital I/O.
External Interrupt 2.
RB3/CCP2
RB3
CCP2
36 39 11
I/O
I/O
TTL
ST
Digital I/O.
Capture2 input, Compare2 output, PWM2 output.
RB4 37 41 14 I/O TTL Digital I/O. Interrupt-on-change pin.
RB5/PGM
RB5
PGM
38 42 15
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
Low Voltage ICSP programming enable pin.
RB6/PGC
RB6
PGC
39 43 16
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming clock
pin.
RB7/PGD
RB7
PGD
40 44 17
I/O
I/O
TTL
ST
Digital I/O. Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming data
pin.
TABLE 1-3: PIC18F4X2 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP PLCC TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) © 2006 Microchip Technology Inc. DS39564C-page 15
PIC18FXX2
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
RC0
T1OSO
T1CKI
15 16 32
I/O
O
I
ST
—
ST
Digital I/O.
Timer1 oscillator output.
Timer1/Timer3 external clock input.
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2
16 18 35
I/O
I
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator input.
Capture2 input, Compare2 output, PWM2 output.
RC2/CCP1
RC2
CCP1
17 19 36
I/O
I/O
ST
ST
Digital I/O.
Capture1 input/Compare1 output/PWM1 output.
RC3/SCK/SCL
RC3
SCK
SCL
18 20 37
I/O
I/O
I/O
ST
ST
ST
Digital I/O.
Synchronous serial clock input/output for
SPI mode.
Synchronous serial clock input/output for
I
2C mode.
RC4/SDI/SDA
RC4
SDI
SDA
23 25 42
I/O
I
I/O
ST
ST
ST
Digital I/O.
SPI Data In.
I
2C Data I/O.
RC5/SDO
RC5
SDO
24 26 43
I/O
O
ST
—
Digital I/O.
SPI Data Out.
RC6/TX/CK
RC6
TX
CK
25 27 44
I/O
O
I/O
ST
—
ST
Digital I/O.
USART Asynchronous Transmit.
USART Synchronous Clock (see related RX/DT).
RC7/RX/DT
RC7
RX
DT
26 29 1
I/O
I
I/O
ST
ST
ST
Digital I/O.
USART Asynchronous Receive.
USART Synchronous Data (see related TX/CK).
TABLE 1-3: PIC18F4X2 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP PLCC TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) PIC18FXX2
DS39564C-page 16 © 2006 Microchip Technology Inc.
PORTD is a bi-directional I/O port, or a Parallel Slave
Port (PSP) for interfacing to a microprocessor port.
These pins have TTL input buffers when PSP module
is enabled.
RD0/PSP0 19 21 38 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD1/PSP1 20 22 39 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD2/PSP2 21 23 40 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD3/PSP3 22 24 41 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD4/PSP4 27 30 2 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD5/PSP5 28 31 3 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD6/PSP6 29 32 4 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
RD7/PSP7 30 33 5 I/O ST
TTL
Digital I/O.
Parallel Slave Port Data.
PORTE is a bi-directional I/O port.
RE0/RD/AN5
RE0
RD
AN5
8 9 25 I/O
ST
TTL
Analog
Digital I/O.
Read control for parallel slave port
(see also WR and CS pins).
Analog input 5.
RE1/WR/AN6
RE1
WR
AN6
9 10 26 I/O
ST
TTL
Analog
Digital I/O.
Write control for parallel slave port
(see CS and RD pins).
Analog input 6.
RE2/CS/AN7
RE2
CS
AN7
10 11 27 I/O
ST
TTL
Analog
Digital I/O.
Chip Select control for parallel slave port
(see related RD and WR).
Analog input 7.
VSS 12, 31 13, 34 6, 29 P — Ground reference for logic and I/O pins.
VDD 11, 32 12, 35 7, 28 P — Positive supply for logic and I/O pins.
TABLE 1-3: PIC18F4X2 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
DIP PLCC TQFP
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power
OD = Open Drain (no P diode to VDD) © 2006 Microchip Technology Inc. DS39564C-page 17
PIC18FXX2
2.0 OSCILLATOR
CONFIGURATIONS
2.1 Oscillator Types
The PIC18FXX2 can be operated in eight different
Oscillator modes. The user can program three configuration
bits (FOSC2, FOSC1, and FOSC0) to select one
of these eight modes:
1. LP Low Power Crystal
2. XT Crystal/Resonator
3. HS High Speed Crystal/Resonator
4. HS + PLL High Speed Crystal/Resonator
with PLL enabled
5. RC External Resistor/Capacitor
6. RCIO External Resistor/Capacitor with
I/O pin enabled
7. EC External Clock
8. ECIO External Clock with I/O pin
enabled
2.2 Crystal Oscillator/Ceramic
Resonators
In XT, LP, HS or HS+PLL Oscillator modes, a crystal or
ceramic resonator is connected to the OSC1 and
OSC2 pins to establish oscillation. Figure 2-1 shows
the pin connections.
The PIC18FXX2 oscillator design requires the use of a
parallel cut crystal.
FIGURE 2-1: CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
CONFIGURATION)
TABLE 2-1: CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Note: Use of a series cut crystal may give a frequency
out of the crystal manufacturers
specifications.
Note 1: See Table 2-1 and Table 2-2 for
recommended values of C1 and C2.
2: A series resistor (RS) may be required for
AT strip cut crystals.
3: RF varies with the Oscillator mode chosen.
C1(1)
C2(1)
XTAL
OSC2
OSC1
RF(3)
SLEEP
To
Logic
PIC18FXXX
RS(2)
Internal
Ranges Tested:
Mode Freq C1 C2
XT 455 kHz
2.0 MHz
4.0 MHz
68 - 100 pF
15 - 68 pF
15 - 68 pF
68 - 100 pF
15 - 68 pF
15 - 68 pF
HS 8.0 MHz
16.0 MHz
10 - 68 pF
10 - 22 pF
10 - 68 pF
10 - 22 pF
These values are for design guidance only.
See notes following this table.
Resonators Used:
455 kHz Panasonic EFO-A455K04B ± 0.3%
2.0 MHz Murata Erie CSA2.00MG ± 0.5%
4.0 MHz Murata Erie CSA4.00MG ± 0.5%
8.0 MHz Murata Erie CSA8.00MT ± 0.5%
16.0 MHz Murata Erie CSA16.00MX ± 0.5%
All resonators used did not have built-in capacitors.
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: When operating below 3V VDD, or when
using certain ceramic resonators at any
voltage, it may be necessary to use
high-gain HS mode, try a lower frequency
resonator, or switch to a crystal oscillator.
3: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropriate
values of external components, or
verify oscillator performance. PIC18FXX2
DS39564C-page 18 © 2006 Microchip Technology Inc.
TABLE 2-2: CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
An external clock source may also be connected to the
OSC1 pin in the HS, XT and LP modes, as shown in
Figure 2-2.
FIGURE 2-2: EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
2.3 RC Oscillator
For timing-insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT) values
and the operating temperature. In addition to this,
the oscillator frequency will vary from unit to unit due to
normal process parameter variation. Furthermore, the
difference in lead frame capacitance between package
types will also affect the oscillation frequency, especially
for low CEXT values. The user also needs to take
into account variation due to tolerance of external R
and C components used. Figure 2-3 shows how the
R/C combination is connected.
In the RC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic.
FIGURE 2-3: RC OSCILLATOR MODE
The RCIO Oscillator mode functions like the RC mode,
except that the OSC2 pin becomes an additional general
purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6).
Ranges Tested:
Mode Freq C1 C2
LP 32.0 kHz 33 pF 33 pF
200 kHz 15 pF 15 pF
XT 200 kHz 22-68 pF 22-68 pF
1.0 MHz 15 pF 15 pF
4.0 MHz 15 pF 15 pF
HS 4.0 MHz 15 pF 15 pF
8.0 MHz 15-33 pF 15-33 pF
20.0 MHz 15-33 pF 15-33 pF
25.0 MHz 15-33 pF 15-33 pF
These values are for design guidance only.
See notes following this table.
Crystals Used
32.0 kHz Epson C-001R32.768K-A ± 20 PPM
200 kHz STD XTL 200.000KHz ± 20 PPM
1.0 MHz ECS ECS-10-13-1 ± 50 PPM
4.0 MHz ECS ECS-40-20-1 ± 50 PPM
8.0 MHz Epson CA-301 8.000M-C ± 30 PPM
20.0 MHz Epson CA-301 20.000M-C ± 30 PPM
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: Rs may be required in HS mode, as well
as XT mode, to avoid overdriving crystals
with low drive level specification.
3: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropriate
values of external components., or
verify oscillator performance.
OSC1
Open OSC2
Clock from
Ext. System PIC18FXXX
Note: If the oscillator frequency divided by 4 signal
is not required in the application, it is
recommended to use RCIO mode to save
current.
OSC2/CLKO
CEXT
REXT
PIC18FXXX
OSC1
FOSC/4
Internal
Clock
VDD
VSS
Recommended values:3 kΩ ≤ REXT ≤ 100 kΩ
CEXT > 20pF© 2006 Microchip Technology Inc. DS39564C-page 19
PIC18FXX2
2.4 External Clock Input
The EC and ECIO Oscillator modes require an external
clock source to be connected to the OSC1 pin. The
feedback device between OSC1 and OSC2 is turned
off in these modes to save current. There is no oscillator
start-up time required after a Power-on Reset or
after a recovery from SLEEP mode.
In the EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 2-4 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-4: EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional general
purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6). Figure 2-5 shows the pin connections
for the ECIO Oscillator mode.
FIGURE 2-5: EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
2.5 HS/PLL
A Phase Locked Loop circuit is provided as a programmable
option for users that want to multiply the frequency
of the incoming crystal oscillator signal by 4.
For an input clock frequency of 10 MHz, the internal
clock frequency will be multiplied to 40 MHz. This is
useful for customers who are concerned with EMI due
to high frequency crystals.
The PLL can only be enabled when the oscillator configuration
bits are programmed for HS mode. If they are
programmed for any other mode, the PLL is not
enabled and the system clock will come directly from
OSC1.
The PLL is one of the modes of the FOSC<2:0> configuration
bits. The Oscillator mode is specified during
device programming.
A PLL lock timer is used to ensure that the PLL has
locked before device execution starts. The PLL lock
timer has a time-out that is called TPLL.
FIGURE 2-6: PLL BLOCK DIAGRAM
OSC1
FOSC/4 OSC2
Clock from
Ext. System PIC18FXXX
OSC1
RA6 I/O (OSC2)
Clock from
Ext. System PIC18FXXX MUX
VCO Loop
Filter
Divide by 4
Crystal
Osc
OSC2
OSC1
PLL Enable
FIN
FOUT SYSCLK
Phase
Comparator
(from Configuration HS Osc
bit Register)PIC18FXX2
DS39564C-page 20 © 2006 Microchip Technology Inc.
2.6 Oscillator Switching Feature
The PIC18FXX2 devices include a feature that allows
the system clock source to be switched from the main
oscillator to an alternate low frequency clock source.
For the PIC18FXX2 devices, this alternate clock source
is the Timer1 oscillator. If a low frequency crystal (32
kHz, for example) has been attached to the Timer1
oscillator pins and the Timer1 oscillator has been
enabled, the device can switch to a Low Power Execution
mode. Figure 2-7 shows a block diagram of the
system clock sources. The clock switching feature is
enabled by programming the Oscillator Switching
Enable (OSCSEN) bit in Configuration Register1H to a
’0’. Clock switching is disabled in an erased device.
See Section 11.0 for further details of the Timer1 oscillator.
See Section 19.0 for Configuration Register
details.
FIGURE 2-7: DEVICE CLOCK SOURCES
PIC18FXXX
TOSC
4 x PLL
TT1P
TSCLK
Clock
Source MUX
TOSC/4
Timer1 Oscillator
T1OSCEN
Enable
Oscillator
T1OSO
T1OSI
Clock Source option
for other modules
OSC1
OSC2
SLEEP
Main Oscillator© 2006 Microchip Technology Inc. DS39564C-page 21
PIC18FXX2
2.6.1 SYSTEM CLOCK SWITCH BIT
The system clock source switching is performed under
software control. The system clock switch bit, SCS
(OSCCON<0>) controls the clock switching. When the
SCS bit is ’0’, the system clock source comes from the
main oscillator that is selected by the FOSC configuration
bits in Configuration Register1H. When the SCS bit
is set, the system clock source will come from the
Timer1 oscillator. The SCS bit is cleared on all forms of
RESET.
REGISTER 2-1: OSCCON REGISTER
Note: The Timer1 oscillator must be enabled and
operating to switch the system clock
source. The Timer1 oscillator is enabled by
setting the T1OSCEN bit in the Timer1
control register (T1CON). If the Timer1
oscillator is not enabled, then any write to
the SCS bit will be ignored (SCS bit forced
cleared) and the main oscillator will
continue to be the system clock source.
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-1
— — — — — — — SCS
bit 7 bit 0
bit 7-1 Unimplemented: Read as '0'
bit 0 SCS: System Clock Switch bit
When OSCSEN configuration bit = ’0’ and T1OSCEN bit is set:
1 = Switch to Timer1 oscillator/clock pin
0 = Use primary oscillator/clock input pin
When OSCSEN and T1OSCEN are in other states:
bit is forced clear
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 22 © 2006 Microchip Technology Inc.
2.6.2 OSCILLATOR TRANSITIONS
The PIC18FXX2 devices contain circuitry to prevent
“glitches” when switching between oscillator sources.
Essentially, the circuitry waits for eight rising edges of
the clock source that the processor is switching to. This
ensures that the new clock source is stable and that its
pulse width will not be less than the shortest pulse
width of the two clock sources.
A timing diagram indicating the transition from the main
oscillator to the Timer1 oscillator is shown in
Figure 2-8. The Timer1 oscillator is assumed to be running
all the time. After the SCS bit is set, the processor
is frozen at the next occurring Q1 cycle. After eight synchronization
cycles are counted from the Timer1 oscillator,
operation resumes. No additional delays are
required after the synchronization cycles.
FIGURE 2-8: TIMING DIAGRAM FOR TRANSITION FROM OSC1 TO TIMER1 OSCILLATOR
The sequence of events that takes place when switching
from the Timer1 oscillator to the main oscillator will
depend on the mode of the main oscillator. In addition
to eight clock cycles of the main oscillator, additional
delays may take place.
If the main oscillator is configured for an external crystal
(HS, XT, LP), then the transition will take place after
an oscillator start-up time (TOST) has occurred. A timing
diagram, indicating the transition from the Timer1 oscillator
to the main oscillator for HS, XT and LP modes, is
shown in Figure 2-9.
FIGURE 2-9: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS, XT, LP)
Q2 Q3 Q4 Q1 Q2 Q3
OSC1
Internal
SCS
(OSCCON<0>)
Program PC PC + 2
Note 1: Delay on internal system clock is eight oscillator cycles for synchronization.
Q1
T1OSI
Q4 Q1
PC + 4
Q1
Tscs
Clock
Counter
System
Q2 Q3 Q4 Q1
TDLY
TT1P
TOSC
1 34 5678 2
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3
OSC1
Internal System
SCS
(OSCCON<0>)
Program Counter PC PC + 2
Note 1: TOST = 1024 TOSC (drawing not to scale).
T1OSI
Clock
OSC2
TOST
Q1
PC + 6
TT1P
TOSC
TSCS
1 2 34 567 8© 2006 Microchip Technology Inc. DS39564C-page 23
PIC18FXX2
If the main oscillator is configured for HS-PLL mode, an
oscillator start-up time (TOST) plus an additional PLL
time-out (TPLL) will occur. The PLL time-out is typically
2 ms and allows the PLL to lock to the main oscillator
frequency. A timing diagram indicating the transition
from the Timer1 oscillator to the main oscillator for
HS-PLL mode is shown in Figure 2-10.
FIGURE 2-10: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)
If the main oscillator is configured in the RC, RCIO, EC
or ECIO modes, there is no oscillator start-up time-out.
Operation will resume after eight cycles of the main
oscillator have been counted. A timing diagram, indicating
the transition from the Timer1 oscillator to the
main oscillator for RC, RCIO, EC and ECIO modes, is
shown in Figure 2-11.
FIGURE 2-11: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)
Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2
OSC1
Internal System
SCS
(OSCCON<0>)
Program Counter PC PC + 2
Note 1: TOST = 1024 TOSC (drawing not to scale).
T1OSI
Clock
TOST
Q3
PC + 4
TPLL
TOSC
TT1P
TSCS
Q4
OSC2
PLL Clock
Input 1 234 5678
Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3
OSC1
Internal System
SCS
(OSCCON<0>)
Program Counter PC PC + 2
Note 1: RC Oscillator mode assumed.
PC + 4
T1OSI
Clock
OSC2
Q4 TT1P
TOSC
TSCS
1 2 3 4 5 6 7 8PIC18FXX2
DS39564C-page 24 © 2006 Microchip Technology Inc.
2.7 Effects of SLEEP Mode on the
On-Chip Oscillator
When the device executes a SLEEP instruction, the
on-chip clocks and oscillator are turned off and the
device is held at the beginning of an instruction cycle
(Q1 state). With the oscillator off, the OSC1 and OSC2
signals will stop oscillating. Since all the transistor
switching currents have been removed, SLEEP mode
achieves the lowest current consumption of the device
(only leakage currents). Enabling any on-chip feature
that will operate during SLEEP will increase the current
consumed during SLEEP. The user can wake from
SLEEP through external RESET, Watchdog Timer
Reset, or through an interrupt.
TABLE 2-3: OSC1 AND OSC2 PIN STATES IN SLEEP MODE
2.8 Power-up Delays
Power up delays are controlled by two timers, so that
no external RESET circuitry is required for most applications.
The delays ensure that the device is kept in
RESET, until the device power supply and clock are
stable. For additional information on RESET operation,
see Section 3.0.
The first timer is the Power-up Timer (PWRT), which
optionally provides a fixed delay of 72 ms (nominal) on
power-up only (POR and BOR). The second timer is
the Oscillator Start-up Timer (OST), intended to keep
the chip in RESET until the crystal oscillator is stable.
With the PLL enabled (HS/PLL Oscillator mode), the
time-out sequence following a Power-on Reset is different
from other Oscillator modes. The time-out
sequence is as follows: First, the PWRT time-out is
invoked after a POR time delay has expired. Then, the
Oscillator Start-up Timer (OST) is invoked. However,
this is still not a sufficient amount of time to allow the
PLL to lock at high frequencies. The PWRT timer is
used to provide an additional fixed 2 ms (nominal)
time-out to allow the PLL ample time to lock to the
incoming clock frequency.
OSC Mode OSC1 Pin OSC2 Pin
RC Floating, external resistor
should pull high
At logic low
RCIO Floating, external resistor
should pull high
Configured as PORTA, bit 6
ECIO Floating Configured as PORTA, bit 6
EC Floating At logic low
LP, XT, and HS Feedback inverter disabled, at
quiescent voltage level
Feedback inverter disabled, at
quiescent voltage level
Note: See Table 3-1, in the “Reset” section, for time-outs due to SLEEP and MCLR Reset.© 2006 Microchip Technology Inc. DS39564C-page 25
PIC18FXX2
3.0 RESET
The PIC18FXXX differentiates between various kinds
of RESET:
a) Power-on Reset (POR)
b) MCLR Reset during normal operation
c) MCLR Reset during SLEEP
d) Watchdog Timer (WDT) Reset (during normal
operation)
e) Programmable Brown-out Reset (BOR)
f) RESET Instruction
g) Stack Full Reset
h) Stack Underflow Reset
Most registers are unaffected by a RESET. Their status
is unknown on POR and unchanged by all other
RESETS. The other registers are forced to a “RESET
state” on Power-on Reset, MCLR, WDT Reset, Brownout
Reset, MCLR Reset during SLEEP and by the
RESET instruction.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal operation.
Status bits from the RCON register, RI, TO, PD,
POR and BOR, are set or cleared differently in different
RESET situations, as indicated in Table 3-2. These bits
are used in software to determine the nature of the
RESET. See Table 3-3 for a full description of the
RESET states of all registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 3-1.
The Enhanced MCU devices have a MCLR noise filter
in the MCLR Reset path. The filter will detect and
ignore small pulses.
The MCLR pin is not driven low by any internal
RESETS, including the WDT.
FIGURE 3-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
S
R Q
External Reset
MCLR
VDD
OSC1
WDT
Module
VDD Rise
Detect
OST/PWRT
On-chip
RC OSC(1)
WDT
Time-out
Power-on Reset
OST
10-bit Ripple Counter
PWRT
Chip_Reset
10-bit Ripple Counter
Reset
Enable OST(2)
Enable PWRT
SLEEP
Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.
2: See Table 3-1 for time-out situations.
Brown-out
Reset BOREN
RESET
Instruction
Stack
Pointer Stack Full/Underflow ResetPIC18FXX2
DS39564C-page 26 © 2006 Microchip Technology Inc.
3.1 Power-On Reset (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected. To take advantage of the POR circuitry,
just tie the MCLR pin directly (or through a resistor)
to VDD. This will eliminate external RC components
usually needed to create a Power-on Reset delay. A
minimum rise rate for VDD is specified
(parameter D004). For a slow rise time, see Figure 3-2.
When the device starts normal operation (i.e., exits the
RESET condition), device operating parameters (voltage,
frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in RESET until the operating
conditions are met.
FIGURE 3-2: EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
3.2 Power-up Timer (PWRT)
The Power-up Timer provides a fixed nominal time-out
(parameter 33) only on power-up from the POR. The
Power-up Timer operates on an internal RC oscillator.
The chip is kept in RESET as long as the PWRT is
active. The PWRT’s time delay allows VDD to rise to an
acceptable level. A configuration bit is provided to
enable/disable the PWRT.
The power-up time delay will vary from chip-to-chip due
to VDD, temperature and process variation. See DC
parameter D033 for details.
3.3 Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over (parameter 32). This ensures that
the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP and HS
modes and only on Power-on Reset or wake-up from
SLEEP.
3.4 PLL Lock Time-out
With the PLL enabled, the time-out sequence following
a Power-on Reset is different from other Oscillator
modes. A portion of the Power-up Timer is used to provide
a fixed time-out that is sufficient for the PLL to lock
to the main oscillator frequency. This PLL lock time-out
(TPLL) is typically 2 ms and follows the oscillator
start-up time-out (OST).
3.5 Brown-out Reset (BOR)
A configuration bit, BOREN, can disable (if clear/
programmed), or enable (if set) the Brown-out Reset
circuitry. If VDD falls below parameter D005 for greater
than parameter 35, the brown-out situation will reset
the chip. A RESET may not occur if VDD falls below
parameter D005 for less than parameter 35. The chip
will remain in Brown-out Reset until VDD rises above
BVDD. If the Power-up Timer is enabled, it will be
invoked after VDD rises above BVDD; it then will keep
the chip in RESET for an additional time delay
(parameter 33). If VDD drops below BVDD while the
Power-up Timer is running, the chip will go back into a
Brown-out Reset and the Power-up Timer will be initialized.
Once VDD rises above BVDD, the Power-up Timer
will execute the additional time delay.
3.6 Time-out Sequence
On power-up, the time-out sequence is as follows:
First, PWRT time-out is invoked after the POR time
delay has expired. Then, OST is activated. The total
time-out will vary based on oscillator configuration and
the status of the PWRT. For example, in RC mode with
the PWRT disabled, there will be no time-out at all.
Figure 3-3, Figure 3-4, Figure 3-5, Figure 3-6 and
Figure 3-7 depict time-out sequences on power-up.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, the time-outs will expire.
Bringing MCLR high will begin execution immediately
(Figure 3-5). This is useful for testing purposes or to
synchronize more than one PIC18FXXX device operating
in parallel.
Table 3-2 shows the RESET conditions for some
Special Function Registers, while Table 3-3 shows the
RESET conditions for all the registers.
Note 1: External Power-on Reset circuit is required
only if the VDD power-up slope is too slow.
The diode D helps discharge the capacitor
quickly when VDD powers down.
2: R < 40 kΩ is recommended to make sure that
the voltage drop across R does not violate
the device’s electrical specification.
3: R1 = 100Ω to 1 kΩ will limit any current flowing
into MCLR from external capacitor C, in
the event of MCLR/VPP pin breakdown due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS).
C
R1
D R
VDD
MCLR
PIC18FXXX© 2006 Microchip Technology Inc. DS39564C-page 27
PIC18FXX2
TABLE 3-1: TIME-OUT IN VARIOUS SITUATIONS
REGISTER 3-1: RCON REGISTER BITS AND POSITIONS
TABLE 3-2: STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
Oscillator
Configuration
Power-up(2)
Brown-out
Wake-up from
SLEEP or
PWRTE = 0 PWRTE = 1 Oscillator Switch
HS with PLL enabled(1) 72 ms + 1024 TOSC
+ 2ms
1024 TOSC
+ 2 ms
72 ms(2) + 1024 TOSC
+ 2 ms 1024 TOSC + 2 ms
HS, XT, LP 72 ms + 1024 TOSC 1024 TOSC 72 ms(2) + 1024 TOSC 1024 TOSC
EC 72 ms — 72 ms(2) —
External RC 72 ms — 72 ms(2) —
Note 1: 2 ms is the nominal time required for the 4x PLL to lock.
2: 72 ms is the nominal power-up timer delay, if implemented.
R/W-0 U-0 U-0 R/W-1 R-1 R-1 R/W-0 R/W-0
IPEN — — RI TO PD POR BOR
bit 7 bit 0
Note 1: Refer to Section 4.14 (page 53) for bit definitions.
Condition Program
Counter
RCON
Register RI TO PD POR BOR STKFUL STKUNF
Power-on Reset 0000h 0--1 1100 1 1 1 0 0 u u
MCLR Reset during normal
operation
0000h 0--u uuuu u u u u u u u
Software Reset during normal
operation
0000h 0--0 uuuu 0 u u u u u u
Stack Full Reset during normal
operation
0000h 0--u uu11 u u u u u u 1
Stack Underflow Reset during
normal operation
0000h 0--u uu11 u u u u u 1 u
MCLR Reset during SLEEP 0000h 0--u 10uu u 1 0 u u u u
WDT Reset 0000h 0--u 01uu 1 0 1 u u u u
WDT Wake-up PC + 2 u--u 00uu u 0 0 u u u u
Brown-out Reset 0000h 0--1 11u0 1 1 1 1 0 u u
Interrupt wake-up from SLEEP PC + 2(1) u--u 00uu u 1 0 u u u u
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0'
Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the
interrupt vector (0x000008h or 0x000018h).PIC18FXX2
DS39564C-page 28 © 2006 Microchip Technology Inc.
TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS
Register Applicable Devices Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
TOSU 242 442 252 452 ---0 0000 ---0 0000 ---0 uuuu(3)
TOSH 242 442 252 452 0000 0000 0000 0000 uuuu uuuu(3)
TOSL 242 442 252 452 0000 0000 0000 0000 uuuu uuuu(3)
STKPTR 242 442 252 452 00-0 0000 uu-0 0000 uu-u uuuu(3)
PCLATU 242 442 252 452 ---0 0000 ---0 0000 ---u uuuu
PCLATH 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
PCL 242 442 252 452 0000 0000 0000 0000 PC + 2(2)
TBLPTRU 242 442 252 452 --00 0000 --00 0000 --uu uuuu
TBLPTRH 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
TBLPTRL 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
TABLAT 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
PRODH 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
PRODL 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
INTCON 242 442 252 452 0000 000x 0000 000u uuuu uuuu(1)
INTCON2 242 442 252 452 1111 -1-1 1111 -1-1 uuuu -u-u(1)
INTCON3 242 442 252 452 11-0 0-00 11-0 0-00 uu-u u-uu(1)
INDF0 242 442 252 452 N/A N/A N/A
POSTINC0 242 442 252 452 N/A N/A N/A
POSTDEC0 242 442 252 452 N/A N/A N/A
PREINC0 242 442 252 452 N/A N/A N/A
PLUSW0 242 442 252 452 N/A N/A N/A
FSR0H 242 442 252 452 ---- xxxx ---- uuuu ---- uuuu
FSR0L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
WREG 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
INDF1 242 442 252 452 N/A N/A N/A
POSTINC1 242 442 252 452 N/A N/A N/A
POSTDEC1 242 442 252 452 N/A N/A N/A
PREINC1 242 442 252 452 N/A N/A N/A
PLUSW1 242 442 252 452 N/A N/A N/A
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for RESET value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
Oscillator modes, they are disabled and read ’0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read ’0’. © 2006 Microchip Technology Inc. DS39564C-page 29
PIC18FXX2
FSR1H 242 442 252 452 ---- xxxx ---- uuuu ---- uuuu
FSR1L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
BSR 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu
INDF2 242 442 252 452 N/A N/A N/A
POSTINC2 242 442 252 452 N/A N/A N/A
POSTDEC2 242 442 252 452 N/A N/A N/A
PREINC2 242 442 252 452 N/A N/A N/A
PLUSW2 242 442 252 452 N/A N/A N/A
FSR2H 242 442 252 452 ---- xxxx ---- uuuu ---- uuuu
FSR2L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
STATUS 242 442 252 452 ---x xxxx ---u uuuu ---u uuuu
TMR0H 242 442 252 452 0000 0000 uuuu uuuu uuuu uuuu
TMR0L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
T0CON 242 442 252 452 1111 1111 1111 1111 uuuu uuuu
OSCCON 242 442 252 452 ---- ---0 ---- ---0 ---- ---u
LVDCON 242 442 252 452 --00 0101 --00 0101 --uu uuuu
WDTCON 242 442 252 452 ---- ---0 ---- ---0 ---- ---u
RCON(4) 242 442 252 452 0--q 11qq 0--q qquu u--u qquu
TMR1H 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
TMR1L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
T1CON 242 442 252 452 0-00 0000 u-uu uuuu u-uu uuuu
TMR2 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
PR2 242 442 252 452 1111 1111 1111 1111 1111 1111
T2CON 242 442 252 452 -000 0000 -000 0000 -uuu uuuu
SSPBUF 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
SSPADD 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
SSPSTAT 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
SSPCON1 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
SSPCON2 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for RESET value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
Oscillator modes, they are disabled and read ’0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read ’0’. PIC18FXX2
DS39564C-page 30 © 2006 Microchip Technology Inc.
ADRESH 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
ADRESL 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
ADCON0 242 442 252 452 0000 00-0 0000 00-0 uuuu uu-u
ADCON1 242 442 252 452 00-- 0000 00-- 0000 uu-- uuuu
CCPR1H 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
CCPR1L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
CCP1CON 242 442 252 452 --00 0000 --00 0000 --uu uuuu
CCPR2H 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
CCPR2L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
CCP2CON 242 442 252 452 --00 0000 --00 0000 --uu uuuu
TMR3H 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
TMR3L 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
T3CON 242 442 252 452 0000 0000 uuuu uuuu uuuu uuuu
SPBRG 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
RCREG 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
TXREG 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
TXSTA 242 442 252 452 0000 -010 0000 -010 uuuu -uuu
RCSTA 242 442 252 452 0000 000x 0000 000x uuuu uuuu
EEADR 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
EEDATA 242 442 252 452 0000 0000 0000 0000 uuuu uuuu
EECON1 242 442 252 452 xx-0 x000 uu-0 u000 uu-0 u000
EECON2 242 442 252 452 ---- ---- ---- ---- ---- ----
TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for RESET value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
Oscillator modes, they are disabled and read ’0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read ’0’. © 2006 Microchip Technology Inc. DS39564C-page 31
PIC18FXX2
IPR2 242 442 252 452 ---1 1111 ---1 1111 ---u uuuu
PIR2 242 442 252 452 ---0 0000 ---0 0000 ---u uuuu(1)
PIE2 242 442 252 452 ---0 0000 ---0 0000 ---u uuuu
IPR1
242 442 252 452 1111 1111 1111 1111 uuuu uuuu
242 442 252 452 -111 1111 -111 1111 -uuu uuuu
PIR1
242 442 252 452 0000 0000 0000 0000 uuuu uuuu(1)
242 442 252 452 -000 0000 -000 0000 -uuu uuuu(1)
PIE1
242 442 252 452 0000 0000 0000 0000 uuuu uuuu
242 442 252 452 -000 0000 -000 0000 -uuu uuuu
TRISE 242 442 252 452 0000 -111 0000 -111 uuuu -uuu
TRISD 242 442 252 452 1111 1111 1111 1111 uuuu uuuu
TRISC 242 442 252 452 1111 1111 1111 1111 uuuu uuuu
TRISB 242 442 252 452 1111 1111 1111 1111 uuuu uuuu
TRISA(5,6) 242 442 252 452 -111 1111(5) -111 1111(5) -uuu uuuu(5)
LATE 242 442 252 452 ---- -xxx ---- -uuu ---- -uuu
LATD 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
LATC 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
LATB 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
LATA(5,6) 242 442 252 452 -xxx xxxx(5) -uuu uuuu(5) -uuu uuuu(5)
PORTE 242 442 252 452 ---- -000 ---- -000 ---- -uuu
PORTD 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
PORTC 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
PORTB 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu
PORTA(5,6) 242 442 252 452 -x0x 0000(5) -u0u 0000(5) -uuu uuuu(5)
TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt
vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 3-2 for RESET value for specific condition.
5: Bit 6 of PORTA, LATA, and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other
Oscillator modes, they are disabled and read ’0’.
6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read ’0’. PIC18FXX2
DS39564C-page 32 © 2006 Microchip Technology Inc.
FIGURE 3-3: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD)
FIGURE 3-4: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
FIGURE 3-5: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
TPWRT
TOST
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
TPWRT
TOST
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
TPWRT
TOST© 2006 Microchip Technology Inc. DS39564C-page 33
PIC18FXX2
FIGURE 3-6: SLOW RISE TIME (MCLR TIED TO VDD)
FIGURE 3-7: TIME-OUT SEQUENCE ON POR W/ PLL ENABLED (MCLR TIED TO VDD)
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
0V 1V
5V
TPWRT
TOST
TPWRT
TOST
VDD
MCLR
IINTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
PLL TIME-OUT
TPLL
Note: TOST = 1024 clock cycles.
TPLL ≈ 2 ms max. First three stages of the PWRT timer.PIC18FXX2
DS39564C-page 34 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 35
PIC18FXX2
4.0 MEMORY ORGANIZATION
There are three memory blocks in Enhanced MCU
devices. These memory blocks are:
• Program Memory
• Data RAM
• Data EEPROM
Data and program memory use separate busses,
which allows for concurrent access of these blocks.
Additional detailed information for FLASH program
memory and Data EEPROM is provided in Section 5.0
and Section 6.0, respectively.
4.1 Program Memory Organization
A 21-bit program counter is capable of addressing the
2-Mbyte program memory space. Accessing a location
between the physically implemented memory and the
2-Mbyte address will cause a read of all ’0’s (a NOP
instruction).
The PIC18F252 and PIC18F452 each have 32 Kbytes
of FLASH memory, while the PIC18F242 and
PIC18F442 have 16 Kbytes of FLASH. This means that
PIC18FX52 devices can store up to 16K of single word
instructions, and PIC18FX42 devices can store up to
8K of single word instructions.
The RESET vector address is at 0000h and the
interrupt vector addresses are at 0008h and 0018h.
Figure 4-1 shows the Program Memory Map for
PIC18F242/442 devices and Figure 4-2 shows the
Program Memory Map for PIC18F252/452 devices.PIC18FXX2
DS39564C-page 36 © 2006 Microchip Technology Inc.
FIGURE 4-1: PROGRAM MEMORY MAP
AND STACK FOR
PIC18F442/242
FIGURE 4-2: PROGRAM MEMORY MAP
AND STACK FOR
PIC18F452/252
PC<20:0>
Stack Level 1 •
Stack Level 31
RESET Vector
Low Priority Interrupt Vector
•
•
CALL,RCALL,RETURN
RETFIE,RETLW
21
0000h
0018h
On-Chip
Program Memory
High Priority Interrupt Vector 0008h
User Memory Space
1FFFFFh
4000h
3FFFh
Read '0'
200000h
PC<20:0>
Stack Level 1 •
Stack Level 31
RESET Vector
Low Priority Interrupt Vector
•
•
CALL,RCALL,RETURN
RETFIE,RETLW
21
0000h
0018h
8000h
7FFFh
On-Chip
Program Memory
High Priority Interrupt Vector 0008h
User Memory Space
Read '0'
1FFFFFh
200000h© 2006 Microchip Technology Inc. DS39564C-page 37
PIC18FXX2
4.2 Return Address Stack
The return address stack allows any combination of up
to 31 program calls and interrupts to occur. The PC
(Program Counter) is pushed onto the stack when a
CALL or RCALL instruction is executed, or an interrupt
is acknowledged. The PC value is pulled off the stack
on a RETURN, RETLW or a RETFIE instruction.
PCLATU and PCLATH are not affected by any of the
RETURN or CALL instructions.
The stack operates as a 31-word by 21-bit RAM and a
5-bit stack pointer, with the stack pointer initialized to
00000b after all RESETS. There is no RAM associated
with stack pointer 00000b. This is only a RESET value.
During a CALL type instruction, causing a push onto the
stack, the stack pointer is first incremented and the
RAM location pointed to by the stack pointer is written
with the contents of the PC. During a RETURN type
instruction, causing a pop from the stack, the contents
of the RAM location pointed to by the STKPTR are
transferred to the PC and then the stack pointer is
decremented.
The stack space is not part of either program or data
space. The stack pointer is readable and writable, and
the address on the top of the stack is readable and writable
through SFR registers. Data can also be pushed
to, or popped from, the stack using the top-of-stack
SFRs. Status bits indicate if the stack pointer is at, or
beyond the 31 levels provided.
4.2.1 TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three
register locations, TOSU, TOSH and TOSL hold the
contents of the stack location pointed to by the
STKPTR register. This allows users to implement a
software stack if necessary. After a CALL, RCALL or
interrupt, the software can read the pushed value by
reading the TOSU, TOSH and TOSL registers. These
values can be placed on a user defined software stack.
At return time, the software can replace the TOSU,
TOSH and TOSL and do a return.
The user must disable the global interrupt enable bits
during this time to prevent inadvertent stack
operations.
4.2.2 RETURN STACK POINTER
(STKPTR)
The STKPTR register contains the stack pointer value,
the STKFUL (stack full) status bit, and the STKUNF
(stack underflow) status bits. Register 4-1 shows the
STKPTR register. The value of the stack pointer can be
0 through 31. The stack pointer increments when values
are pushed onto the stack and decrements when
values are popped off the stack. At RESET, the stack
pointer value will be 0. The user may read and write the
stack pointer value. This feature can be used by a Real
Time Operating System for return stack maintenance.
After the PC is pushed onto the stack 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit can only be cleared in software or
by a POR.
The action that takes place when the stack becomes
full depends on the state of the STVREN (Stack Overflow
Reset Enable) configuration bit. Refer to
Section 20.0 for a description of the device configuration
bits. If STVREN is set (default), the 31st push will
push the (PC + 2) value onto the stack, set the STKFUL
bit, and reset the device. The STKFUL bit will remain
set and the stack pointer will be set to ‘0’.
If STVREN is cleared, the STKFUL bit will be set on the
31st push and the stack pointer will increment to 31.
Any additional pushes will not overwrite the 31st push,
and STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and sets the STKUNF bit, while the stack
pointer remains at 0. The STKUNF bit will remain set
until cleared in software or a POR occurs.
Note: Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the RESET vector, where the
stack conditions can be verified and
appropriate actions can be taken.PIC18FXX2
DS39564C-page 38 © 2006 Microchip Technology Inc.
REGISTER 4-1: STKPTR REGISTER
FIGURE 4-3: RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
4.2.3 PUSH AND POP INSTRUCTIONS
Since the Top-of-Stack (TOS) is readable and writable,
the ability to push values onto the stack and pull values
off the stack without disturbing normal program execution
is a desirable option. To push the current PC value
onto the stack, a PUSH instruction can be executed.
This will increment the stack pointer and load the current
PC value onto the stack. TOSU, TOSH and TOSL
can then be modified to place a return address on the
stack.
The ability to pull the TOS value off of the stack and
replace it with the value that was previously pushed
onto the stack, without disturbing normal execution, is
achieved by using the POP instruction. The POP instruction
discards the current TOS by decrementing the
stack pointer. The previous value pushed onto the
stack then becomes the TOS value.
4.2.4 STACK FULL/UNDERFLOW RESETS
These resets are enabled by programming the
STVREN configuration bit. When the STVREN bit is
disabled, a full or underflow condition will set the appropriate
STKFUL or STKUNF bit, but not cause a device
RESET. When the STVREN bit is enabled, a full or
underflow will set the appropriate STKFUL or STKUNF
bit and then cause a device RESET. The STKFUL or
STKUNF bits are only cleared by the user software or
a POR Reset.
R/C-0 R/C-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
STKOVF STKUNF — SP4 SP3 SP2 SP1 SP0
bit 7 bit 0
bit 7(1) STKOVF: Stack Full Flag bit
1 = Stack became full or overflowed
0 = Stack has not become full or overflowed
bit 6(1) STKUNF: Stack Underflow Flag bit
1 = Stack underflow occurred
0 = Stack underflow did not occur
bit 5 Unimplemented: Read as '0'
bit 4-0 SP4:SP0: Stack Pointer Location bits
Note 1: Bit 7 and bit 6 can only be cleared in user software or by a POR.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown
00011
0x001A34
11111
11110
11101
00010
00001
00000
00010
Return Address Stack
Top of Stack 0x000D58
TOSU TOSH TOSL
0x00 0x1A 0x34
STKPTR<4:0>© 2006 Microchip Technology Inc. DS39564C-page 39
PIC18FXX2
4.3 Fast Register Stack
A “fast interrupt return” option is available for interrupts.
A Fast Register Stack is provided for the STATUS,
WREG and BSR registers and are only one in depth.
The stack is not readable or writable and is loaded with
the current value of the corresponding register when
the processor vectors for an interrupt. The values in the
registers are then loaded back into the working registers,
if the FAST RETURN instruction is used to return
from the interrupt.
A low or high priority interrupt source will push values
into the stack registers. If both low and high priority
interrupts are enabled, the stack registers cannot be
used reliably for low priority interrupts. If a high priority
interrupt occurs while servicing a low priority interrupt,
the stack register values stored by the low priority interrupt
will be overwritten.
If high priority interrupts are not disabled during low priority
interrupts, users must save the key registers in
software during a low priority interrupt.
If no interrupts are used, the fast register stack can be
used to restore the STATUS, WREG and BSR registers
at the end of a subroutine call. To use the fast register
stack for a subroutine call, a FAST CALL instruction
must be executed.
Example 4-1 shows a source code example that uses
the fast register stack.
EXAMPLE 4-1: FAST REGISTER STACK
CODE EXAMPLE
4.4 PCL, PCLATH and PCLATU
The program counter (PC) specifies the address of the
instruction to fetch for execution. The PC is 21-bits
wide. The low byte is called the PCL register. This register
is readable and writable. The high byte is called
the PCH register. This register contains the PC<15:8>
bits and is not directly readable or writable. Updates to
the PCH register may be performed through the
PCLATH register. The upper byte is called PCU. This
register contains the PC<20:16> bits and is not directly
readable or writable. Updates to the PCU register may
be performed through the PCLATU register.
The PC addresses bytes in the program memory. To
prevent the PC from becoming misaligned with word
instructions, the LSB of PCL is fixed to a value of ’0’.
The PC increments by 2 to address sequential
instructions in the program memory.
The CALL, RCALL, GOTO and program branch
instructions write to the program counter directly. For
these instructions, the contents of PCLATH and
PCLATU are not transferred to the program counter.
The contents of PCLATH and PCLATU will be transferred
to the program counter by an operation that
writes PCL. Similarly, the upper two bytes of the program
counter will be transferred to PCLATH and
PCLATU by an operation that reads PCL. This is useful
for computed offsets to the PC (see Section 4.8.1).
4.5 Clocking Scheme/Instruction
Cycle
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks, namely Q1, Q2, Q3 and Q4. Internally, the program
counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the instruction register in Q4. The instruction
is decoded and executed during the following Q1
through Q4. The clocks and instruction execution flow
are shown in Figure 4-4.
FIGURE 4-4: CLOCK/INSTRUCTION CYCLE
CALL SUB1, FAST ;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
•
•
SUB1 •
•
•
RETURN FAST ;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Q1
Q2
Q3
Q4
PC
OSC2/CLKO
(RC mode)
PC PC+2 PC+4
Fetch INST (PC)
Execute INST (PC-2)
Fetch INST (PC+2)
Execute INST (PC)
Fetch INST (PC+4)
Execute INST (PC+2)
Internal
Phase
ClockPIC18FXX2
DS39564C-page 40 © 2006 Microchip Technology Inc.
4.6 Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO)
then two cycles are required to complete the instruction
(Example 4-2).
A fetch cycle begins with the program counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the “Instruction Register” (IR) in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3, and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
EXAMPLE 4-2: INSTRUCTION PIPELINE FLOW
4.7 Instructions in Program Memory
The program memory is addressed in bytes. Instructions
are stored as two bytes or four bytes in program
memory. The Least Significant Byte of an instruction
word is always stored in a program memory location
with an even address (LSB =’0’). Figure 4-5 shows an
example of how instruction words are stored in the program
memory. To maintain alignment with instruction
boundaries, the PC increments in steps of 2 and the
LSB will always read ’0’ (see Section 4.4).
The CALL and GOTO instructions have an absolute program
memory address embedded into the instruction.
Since instructions are always stored on word boundaries,
the data contained in the instruction is a word
address. The word address is written to PC<20:1>,
which accesses the desired byte address in program
memory. Instruction #2 in Figure 4-5 shows how the
instruction “GOTO 000006h’ is encoded in the program
memory. Program branch instructions which encode a
relative address offset operate in the same manner.
The offset value stored in a branch instruction represents
the number of single word instructions that the
PC will be offset by. Section 20.0 provides further
details of the instruction set.
FIGURE 4-5: INSTRUCTIONS IN PROGRAM MEMORY
All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline while the new instruction is being fetched and then executed.
TCY0 TCY1 TCY2 TCY3 TCY4 TCY5
1. MOVLW 55h Fetch 1 Execute 1
2. MOVWF PORTB Fetch 2 Execute 2
3. BRA SUB_1 Fetch 3 Execute 3
4. BSF PORTA, BIT3 (Forced NOP) Fetch 4 Flush (NOP)
5. Instruction @ address SUB_1 Fetch SUB_1 Execute SUB_1
Word Address
LSB = 1 LSB = 0 ↓
Program Memory
Byte Locations →
000000h
000002h
000004h
000006h
Instruction 1: MOVLW 055h 0Fh 55h 000008h
Instruction 2: GOTO 000006h EFh 03h 00000Ah
F0h 00h 00000Ch
Instruction 3: MOVFF 123h, 456h C1h 23h 00000Eh
F4h 56h 000010h
000012h
000014h© 2006 Microchip Technology Inc. DS39564C-page 41
PIC18FXX2
4.7.1 TWO-WORD INSTRUCTIONS
The PIC18FXX2 devices have four two-word instructions:
MOVFF, CALL, GOTO and LFSR. The second
word of these instructions has the 4 MSBs set to 1’s
and is a special kind of NOP instruction. The lower 12
bits of the second word contain data to be used by the
instruction. If the first word of the instruction is executed,
the data in the second word is accessed. If the
second word of the instruction is executed by itself (first
word was skipped), it will execute as a NOP. This action
is necessary when the two-word instruction is preceded
by a conditional instruction that changes the PC. A program
example that demonstrates this concept is shown
in Example 4-3. Refer to Section 20.0 for further details
of the instruction set.
EXAMPLE 4-3: TWO-WORD INSTRUCTIONS
4.8 Lookup Tables
Lookup tables are implemented two ways. These are:
• Computed GOTO
• Table Reads
4.8.1 COMPUTED GOTO
A computed GOTO is accomplished by adding an offset
to the program counter (ADDWF PCL).
A lookup table can be formed with an ADDWF PCL
instruction and a group of RETLW 0xnn instructions.
WREG is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCL instruction. The next
instruction executed will be one of the RETLW 0xnn
instructions, that returns the value 0xnn to the calling
function.
The offset value (value in WREG) specifies the number
of bytes that the program counter should advance.
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
4.8.2 TABLE READS/TABLE WRITES
A better method of storing data in program memory
allows 2 bytes of data to be stored in each instruction
location.
Lookup table data may be stored 2 bytes per program
word by using table reads and writes. The table pointer
(TBLPTR) specifies the byte address and the table
latch (TABLAT) contains the data that is read from, or
written to program memory. Data is transferred to/from
program memory, one byte at a time.
A description of the Table Read/Table Write operation
is shown in Section 3.0.
CASE 1:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; No, execute 2-word instruction
1111 0100 0101 0110 ; 2nd operand holds address of REG2
0010 0100 0000 0000 ADDWF REG3 ; continue code
CASE 2:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; Yes
1111 0100 0101 0110 ; 2nd operand becomes NOP
0010 0100 0000 0000 ADDWF REG3 ; continue code
Note: The ADDWF PCL instruction does not
update PCLATH and PCLATU. A read
operation on PCL must be performed to
update PCLATH and PCLATU.PIC18FXX2
DS39564C-page 42 © 2006 Microchip Technology Inc.
4.9 Data Memory Organization
The data memory is implemented as static RAM. Each
register in the data memory has a 12-bit address,
allowing up to 4096 bytes of data memory. Figure 4-6
and Figure 4-7 show the data memory organization for
the PIC18FXX2 devices.
The data memory map is divided into as many as 16
banks that contain 256 bytes each. The lower 4 bits of
the Bank Select Register (BSR<3:0>) select which
bank will be accessed. The upper 4 bits for the BSR are
not implemented.
The data memory contains Special Function Registers
(SFR) and General Purpose Registers (GPR). The
SFRs are used for control and status of the controller
and peripheral functions, while GPRs are used for data
storage and scratch pad operations in the user’s application.
The SFRs start at the last location of Bank 15
(0xFFF) and extend downwards. Any remaining space
beyond the SFRs in the Bank may be implemented as
GPRs. GPRs start at the first location of Bank 0 and
grow upwards. Any read of an unimplemented location
will read as ’0’s.
The entire data memory may be accessed directly or
indirectly. Direct addressing may require the use of the
BSR register. Indirect addressing requires the use of a
File Select Register (FSRn) and a corresponding Indirect
File Operand (INDFn). Each FSR holds a 12-bit
address value that can be used to access any location
in the Data Memory map without banking.
The instruction set and architecture allow operations
across all banks. This may be accomplished by indirect
addressing or by the use of the MOVFF instruction. The
MOVFF instruction is a two-word/two-cycle instruction
that moves a value from one register to another.
To ensure that commonly used registers (SFRs and
select GPRs) can be accessed in a single cycle,
regardless of the current BSR values, an Access Bank
is implemented. A segment of Bank 0 and a segment of
Bank 15 comprise the Access RAM. Section 4.10
provides a detailed description of the Access RAM.
4.9.1 GENERAL PURPOSE REGISTER
FILE
The register file can be accessed either directly or indirectly.
Indirect addressing operates using a File Select
Register and corresponding Indirect File Operand. The
operation of indirect addressing is shown in
Section 4.12.
Enhanced MCU devices may have banked memory in
the GPR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other RESETS.
Data RAM is available for use as GPR registers by all
instructions. The top half of Bank 15 (0xF80 to 0xFFF)
contains SFRs. All other banks of data memory contain
GPR registers, starting with Bank 0.
4.9.2 SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers
used by the CPU and Peripheral Modules for controlling
the desired operation of the device. These registers
are implemented as static RAM. A list of these
registers is given in Table 4-1 and Table 4-2.
The SFRs can be classified into two sets; those associated
with the “core” function and those related to the
peripheral functions. Those registers related to the
“core” are described in this section, while those related
to the operation of the peripheral features are
described in the section of that peripheral feature.
The SFRs are typically distributed among the
peripherals whose functions they control.
The unused SFR locations will be unimplemented and
read as '0's. See Table 4-1 for addresses for the SFRs.© 2006 Microchip Technology Inc. DS39564C-page 43
PIC18FXX2
FIGURE 4-6: DATA MEMORY MAP FOR PIC18F242/442
Bank 0
Bank 1
Bank 14
Bank 15
BSR<3:0> Data Memory Map
= 0000
= 0001
= 1111
080h
07Fh
F80h
FFFh
00h
7Fh
80h
FFh
Access Bank
When a = 0,
the BSR is ignored and the
Access Bank is used.
The first 128 bytes are General
Purpose RAM (from Bank 0).
The second 128 bytes are
Special Function Registers
(from Bank 15).
When a = 1,
the BSR is used to specify the
RAM location that the
instruction uses.
F7Fh
F00h
EFFh
1FFh
100h
0FFh
000h Access RAM
FFh
00h
FFh
00h
FFh
00h
GPR
GPR
SFR
Unused
Access RAM high
Access RAM low
Bank 3
to
200h
Unused
= 1110 Read ’00h’
= 0011
(SFRs)
GPR
2FFh
300h
FFh
00h
Bank 2 = 0010PIC18FXX2
DS39564C-page 44 © 2006 Microchip Technology Inc.
FIGURE 4-7: DATA MEMORY MAP FOR PIC18F252/452
Bank 0
Bank 1
Bank 14
Bank 15
BSR<3:0> Data Memory Map
= 0000
= 0001
= 1110
= 1111
080h
07Fh
F80h
FFFh
00h
7Fh
80h
FFh
Access Bank
When a = 0,
the BSR is ignored and the
Access Bank is used.
The first 128 bytes are General
Purpose RAM (from Bank 0).
The second 128 bytes are
Special Function Registers
(from Bank 15).
When a = 1,
the BSR is used to specify the
RAM location that the
instruction uses.
Bank 4
Bank 3
Bank 2
F7Fh
F00h
EFFh
3FFh
300h
2FFh
200h
1FFh
100h
0FFh
000h
= 0110
= 0101
= 0011
= 0010
Access RAM
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
GPR
GPR
GPR
GPR
SFR
Unused
Access RAM high
Access RAM low
Bank 5
GPR
GPR
Bank 6
to
4FFh
400h
5FFh
500h
600h
Unused
Read ’00h’
= 0100
(SFR’s)© 2006 Microchip Technology Inc. DS39564C-page 45
PIC18FXX2
TABLE 4-1: SPECIAL FUNCTION REGISTER MAP
Address Name Address Name Address Name Address Name
FFFh TOSU FDFh INDF2(3) FBFh CCPR1H F9Fh IPR1
FFEh TOSH FDEh POSTINC2(3) FBEh CCPR1L F9Eh PIR1
FFDh TOSL FDDh POSTDEC2(3) FBDh CCP1CON F9Dh PIE1
FFCh STKPTR FDCh PREINC2(3) FBCh CCPR2H F9Ch —
FFBh PCLATU FDBh PLUSW2(3) FBBh CCPR2L F9Bh —
FFAh PCLATH FDAh FSR2H FBAh CCP2CON F9Ah —
FF9h PCL FD9h FSR2L FB9h — F99h —
FF8h TBLPTRU FD8h STATUS FB8h — F98h —
FF7h TBLPTRH FD7h TMR0H FB7h — F97h —
FF6h TBLPTRL FD6h TMR0L FB6h — F96h TRISE(2)
FF5h TABLAT FD5h T0CON FB5h — F95h TRISD(2)
FF4h PRODH FD4h — FB4h — F94h TRISC
FF3h PRODL FD3h OSCCON FB3h TMR3H F93h TRISB
FF2h INTCON FD2h LVDCON FB2h TMR3L F92h TRISA
FF1h INTCON2 FD1h WDTCON FB1h T3CON F91h —
FF0h INTCON3 FD0h RCON FB0h — F90h —
FEFh INDF0(3) FCFh TMR1H FAFh SPBRG F8Fh —
FEEh POSTINC0(3) FCEh TMR1L FAEh RCREG F8Eh —
FEDh POSTDEC0(3) FCDh T1CON FADh TXREG F8Dh LATE(2)
FECh PREINC0(3) FCCh TMR2 FACh TXSTA F8Ch LATD(2)
FEBh PLUSW0(3) FCBh PR2 FABh RCSTA F8Bh LATC
FEAh FSR0H FCAh T2CON FAAh — F8Ah LATB
FE9h FSR0L FC9h SSPBUF FA9h EEADR F89h LATA
FE8h WREG FC8h SSPADD FA8h EEDATA F88h —
FE7h INDF1(3) FC7h SSPSTAT FA7h EECON2 F87h —
FE6h POSTINC1(3) FC6h SSPCON1 FA6h EECON1 F86h —
FE5h POSTDEC1(3) FC5h SSPCON2 FA5h — F85h —
FE4h PREINC1(3) FC4h ADRESH FA4h — F84h PORTE(2)
FE3h PLUSW1(3) FC3h ADRESL FA3h — F83h PORTD(2)
FE2h FSR1H FC2h ADCON0 FA2h IPR2 F82h PORTC
FE1h FSR1L FC1h ADCON1 FA1h PIR2 F81h PORTB
FE0h BSR FC0h — FA0h PIE2 F80h PORTA
Note 1: Unimplemented registers are read as ’0’.
2: This register is not available on PIC18F2X2 devices.
3: This is not a physical register.PIC18FXX2
DS39564C-page 46 © 2006 Microchip Technology Inc.
TABLE 4-2: REGISTER FILE SUMMARY
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Details
on page:
TOSU — — — Top-of-Stack upper Byte (TOS<20:16>) ---0 0000 37
TOSH Top-of-Stack High Byte (TOS<15:8>) 0000 0000 37
TOSL Top-of-Stack Low Byte (TOS<7:0>) 0000 0000 37
STKPTR STKFUL STKUNF — Return Stack Pointer 00-0 0000 38
PCLATU — — — Holding Register for PC<20:16> ---0 0000 39
PCLATH Holding Register for PC<15:8> 0000 0000 39
PCL PC Low Byte (PC<7:0>) 0000 0000 39
TBLPTRU — — bit21(2) Program Memory Table Pointer Upper Byte (TBLPTR<20:16>) --00 0000 58
TBLPTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>) 0000 0000 58
TBLPTRL Program Memory Table Pointer Low Byte (TBLPTR<7:0>) 0000 0000 58
TABLAT Program Memory Table Latch 0000 0000 58
PRODH Product Register High Byte xxxx xxxx 71
PRODL Product Register Low Byte xxxx xxxx 71
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 75
INTCON2 RBPU INTEDG0 INTEDG1 INTEDG2 — TMR0IP — RBIP 1111 -1-1 76
INTCON3 INT2IP INT1IP — INT2IE INT1IE — INT2IF INT1IF 11-0 0-00 77
INDF0 Uses contents of FSR0 to address data memory - value of FSR0 not changed (not a physical register) n/a 50
POSTINC0 Uses contents of FSR0 to address data memory - value of FSR0 post-incremented (not a physical register) n/a 50
POSTDEC0 Uses contents of FSR0 to address data memory - value of FSR0 post-decremented (not a physical register) n/a 50
PREINC0 Uses contents of FSR0 to address data memory - value of FSR0 pre-incremented (not a physical register) n/a 50
PLUSW0 Uses contents of FSR0 to address data memory - value of FSR0 (not a physical register).
Offset by value in WREG.
n/a 50
FSR0H — — — — Indirect Data Memory Address Pointer 0 High Byte ---- 0000 50
FSR0L Indirect Data Memory Address Pointer 0 Low Byte xxxx xxxx 50
WREG Working Register xxxx xxxx n/a
INDF1 Uses contents of FSR1 to address data memory - value of FSR1 not changed (not a physical register) n/a 50
POSTINC1 Uses contents of FSR1 to address data memory - value of FSR1 post-incremented (not a physical register) n/a 50
POSTDEC1 Uses contents of FSR1 to address data memory - value of FSR1 post-decremented (not a physical register) n/a 50
PREINC1 Uses contents of FSR1 to address data memory - value of FSR1 pre-incremented (not a physical register) n/a 50
PLUSW1 Uses contents of FSR1 to address data memory - value of FSR1 (not a physical register).
Offset by value in WREG.
n/a 50
FSR1H — — — — Indirect Data Memory Address Pointer 1 High Byte ---- 0000 50
FSR1L Indirect Data Memory Address Pointer 1 Low Byte xxxx xxxx 50
BSR — — — — Bank Select Register ---- 0000 49
INDF2 Uses contents of FSR2 to address data memory - value of FSR2 not changed (not a physical register) n/a 50
POSTINC2 Uses contents of FSR2 to address data memory - value of FSR2 post-incremented (not a physical register) n/a 50
POSTDEC2 Uses contents of FSR2 to address data memory - value of FSR2 post-decremented (not a physical register) n/a 50
PREINC2 Uses contents of FSR2 to address data memory - value of FSR2 pre-incremented (not a physical register) n/a 50
PLUSW2 Uses contents of FSR2 to address data memory - value of FSR2 (not a physical register).
Offset by value in WREG.
n/a 50
FSR2H — — — — Indirect Data Memory Address Pointer 2 High Byte ---- 0000 50
FSR2L Indirect Data Memory Address Pointer 2 Low Byte xxxx xxxx 50
STATUS — — — N OV Z DC C ---x xxxx 52
TMR0H Timer0 Register High Byte 0000 0000 105
TMR0L Timer0 Register Low Byte xxxx xxxx 105
T0CON TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0 1111 1111 103
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition
Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes.
2: Bit 21 of the TBLPTRU allows access to the device configuration bits.
3: These registers and bits are reserved on the PIC18F2X2 devices; always maintain these clear.© 2006 Microchip Technology Inc. DS39564C-page 47
PIC18FXX2
OSCCON — — — — — — — SCS ---- ---0 21
LVDCON — — IRVST LVDEN LVDL3 LVDL2 LVDL1 LVDL0 --00 0101 191
WDTCON — — — — — — — SWDTE ---- ---0 203
RCON IPEN — — RI TO PD POR BOR 0--1 11qq 53, 28, 84
TMR1H Timer1 Register High Byte xxxx xxxx 107
TMR1L Timer1 Register Low Byte xxxx xxxx 107
T1CON RD16 — T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 107
TMR2 Timer2 Register 0000 0000 111
PR2 Timer2 Period Register 1111 1111 112
T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 111
SSPBUF SSP Receive Buffer/Transmit Register xxxx xxxx 125
SSPADD SSP Address Register in I2C Slave mode. SSP Baud Rate Reload Register in I2C Master mode. 0000 0000 134
SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 126
SSPCON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 127
SSPCON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 137
ADRESH A/D Result Register High Byte xxxx xxxx 187,188
ADRESL A/D Result Register Low Byte xxxx xxxx 187,188
ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE — ADON 0000 00-0 181
ADCON1 ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 182
CCPR1H Capture/Compare/PWM Register1 High Byte xxxx xxxx 121, 123
CCPR1L Capture/Compare/PWM Register1 Low Byte xxxx xxxx 121, 123
CCP1CON — — DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 117
CCPR2H Capture/Compare/PWM Register2 High Byte xxxx xxxx 121, 123
CCPR2L Capture/Compare/PWM Register2 Low Byte xxxx xxxx 121, 123
CCP2CON — — DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 117
TMR3H Timer3 Register High Byte xxxx xxxx 113
TMR3L Timer3 Register Low Byte xxxx xxxx 113
T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 0000 0000 113
SPBRG USART1 Baud Rate Generator 0000 0000 168
RCREG USART1 Receive Register 0000 0000 175, 178,
180
TXREG USART1 Transmit Register 0000 0000 173, 176,
179
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 166
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 167
EEADR Data EEPROM Address Register 0000 0000 65, 69
EEDATA Data EEPROM Data Register 0000 0000 69
EECON2 Data EEPROM Control Register 2 (not a physical register) ---- ---- 65, 69
EECON1 EEPGD CFGS — FREE WRERR WREN WR RD xx-0 x000 66
TABLE 4-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Details
on page:
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition
Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes.
2: Bit 21 of the TBLPTRU allows access to the device configuration bits.
3: These registers and bits are reserved on the PIC18F2X2 devices; always maintain these clear.PIC18FXX2
DS39564C-page 48 © 2006 Microchip Technology Inc.
IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 83
PIR2 — — — EEIF BCLIF LVDIF TMR3IF CCP2IF ---0 0000 79
PIE2 — — — EEIE BCLIE LVDIE TMR3IE CCP2IE ---0 0000 81
IPR1 PSPIP(3) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 1111 1111 82
PIR1 PSPIF(3) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 78
PIE1 PSPIE(3) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 80
TRISE(3) IBF OBF IBOV PSPMODE — Data Direction bits for PORTE 0000 -111 98
TRISD(3) Data Direction Control Register for PORTD 1111 1111 96
TRISC Data Direction Control Register for PORTC 1111 1111 93
TRISB Data Direction Control Register for PORTB 1111 1111 90
TRISA — TRISA6(1) Data Direction Control Register for PORTA -111 1111 87
LATE(3) — — — — — Read PORTE Data Latch,
Write PORTE Data Latch
---- -xxx 99
LATD(3) Read PORTD Data Latch, Write PORTD Data Latch xxxx xxxx 95
LATC Read PORTC Data Latch, Write PORTC Data Latch xxxx xxxx 93
LATB Read PORTB Data Latch, Write PORTB Data Latch xxxx xxxx 90
LATA — LATA6(1) Read PORTA Data Latch, Write PORTA Data Latch(1) -xxx xxxx 87
PORTE(3) Read PORTE pins, Write PORTE Data Latch ---- -000 99
PORTD(3) Read PORTD pins, Write PORTD Data Latch xxxx xxxx 95
PORTC Read PORTC pins, Write PORTC Data Latch xxxx xxxx 93
PORTB Read PORTB pins, Write PORTB Data Latch xxxx xxxx 90
PORTA — RA6(1) Read PORTA pins, Write PORTA Data Latch(1) -x0x 0000 87
TABLE 4-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Details
on page:
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition
Note 1: RA6 and associated bits are configured as port pins in RCIO and ECIO Oscillator mode only and read '0' in all other Oscillator modes.
2: Bit 21 of the TBLPTRU allows access to the device configuration bits.
3: These registers and bits are reserved on the PIC18F2X2 devices; always maintain these clear.© 2006 Microchip Technology Inc. DS39564C-page 49
PIC18FXX2
4.10 Access Bank
The Access Bank is an architectural enhancement
which is very useful for C compiler code optimization.
The techniques used by the C compiler may also be
useful for programs written in assembly.
This data memory region can be used for:
• Intermediate computational values
• Local variables of subroutines
• Faster context saving/switching of variables
• Common variables
• Faster evaluation/control of SFRs (no banking)
The Access Bank is comprised of the upper 128 bytes
in Bank 15 (SFRs) and the lower 128 bytes in Bank 0.
These two sections will be referred to as Access RAM
High and Access RAM Low, respectively. Figure 4-6
and Figure 4-7 indicate the Access RAM areas.
A bit in the instruction word specifies if the operation is
to occur in the bank specified by the BSR register or in
the Access Bank. This bit is denoted by the ’a’ bit (for
access bit).
When forced in the Access Bank (a = 0), the last
address in Access RAM Low is followed by the first
address in Access RAM High. Access RAM High maps
the Special Function registers, so that these registers
can be accessed without any software overhead. This is
useful for testing status flags and modifying control bits.
4.11 Bank Select Register (BSR)
The need for a large general purpose memory space
dictates a RAM banking scheme. The data memory is
partitioned into sixteen banks. When using direct
addressing, the BSR should be configured for the
desired bank.
BSR<3:0> holds the upper 4 bits of the 12-bit RAM
address. The BSR<7:4> bits will always read ’0’s, and
writes will have no effect.
A MOVLB instruction has been provided in the
instruction set to assist in selecting banks.
If the currently selected bank is not implemented, any
read will return all '0's and all writes are ignored. The
STATUS register bits will be set/cleared as appropriate
for the instruction performed.
Each Bank extends up to FFh (256 bytes). All data
memory is implemented as static RAM.
A MOVFF instruction ignores the BSR, since the 12-bit
addresses are embedded into the instruction word.
Section 4.12 provides a description of indirect addressing,
which allows linear addressing of the entire RAM
space.
FIGURE 4-8: DIRECT ADDRESSING
Note 1: For register file map detail, see Table 4-1.
2: The access bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to the
registers of the Access Bank.
3: The MOVFF instruction embeds the entire 12-bit address in the instruction.
Data
Memory(1)
Direct Addressing
Bank Select(2) Location Select(3)
BSR<3:0> 7 From Opcode 0 (3)
00h 01h 0Eh 0Fh
Bank 0 Bank 1 Bank 14 Bank 15
1FFh
100h
0FFh
000h
EFFh
E00h
FFFh
F00hPIC18FXX2
DS39564C-page 50 © 2006 Microchip Technology Inc.
4.12 Indirect Addressing, INDF and
FSR Registers
Indirect addressing is a mode of addressing data memory,
where the data memory address in the instruction
is not fixed. An FSR register is used as a pointer to the
data memory location that is to be read or written. Since
this pointer is in RAM, the contents can be modified by
the program. This can be useful for data tables in the
data memory and for software stacks. Figure 4-9
shows the operation of indirect addressing. This shows
the moving of the value to the data memory address
specified by the value of the FSR register.
Indirect addressing is possible by using one of the
INDF registers. Any instruction using the INDF register
actually accesses the register pointed to by the File
Select Register, FSR. Reading the INDF register itself,
indirectly (FSR = 0), will read 00h. Writing to the INDF
register indirectly, results in a no operation. The FSR
register contains a 12-bit address, which is shown in
Figure 4-10.
The INDFn register is not a physical register. Addressing
INDFn actually addresses the register whose
address is contained in the FSRn register (FSRn is a
pointer). This is indirect addressing.
Example 4-4 shows a simple use of indirect addressing
to clear the RAM in Bank1 (locations 100h-1FFh) in a
minimum number of instructions.
EXAMPLE 4-4: HOW TO CLEAR RAM
(BANK1) USING INDIRECT
ADDRESSING
There are three indirect addressing registers. To
address the entire data memory space (4096 bytes),
these registers are 12-bit wide. To store the 12-bits of
addressing information, two 8-bit registers are
required. These indirect addressing registers are:
1. FSR0: composed of FSR0H:FSR0L
2. FSR1: composed of FSR1H:FSR1L
3. FSR2: composed of FSR2H:FSR2L
In addition, there are registers INDF0, INDF1 and
INDF2, which are not physically implemented. Reading
or writing to these registers activates indirect addressing,
with the value in the corresponding FSR register
being the address of the data. If an instruction writes a
value to INDF0, the value will be written to the address
pointed to by FSR0H:FSR0L. A read from INDF1 reads
the data from the address pointed to by
FSR1H:FSR1L. INDFn can be used in code anywhere
an operand can be used.
If INDF0, INDF1 or INDF2 are read indirectly via an
FSR, all '0's are read (zero bit is set). Similarly, if
INDF0, INDF1 or INDF2 are written to indirectly, the
operation will be equivalent to a NOP instruction and the
STATUS bits are not affected.
4.12.1 INDIRECT ADDRESSING
OPERATION
Each FSR register has an INDF register associated
with it, plus four additional register addresses. Performing
an operation on one of these five registers determines
how the FSR will be modified during indirect
addressing.
When data access is done to one of the five INDFn
locations, the address selected will configure the FSRn
register to:
• Do nothing to FSRn after an indirect access (no
change) - INDFn
• Auto-decrement FSRn after an indirect access
(post-decrement) - POSTDECn
• Auto-increment FSRn after an indirect access
(post-increment) - POSTINCn
• Auto-increment FSRn before an indirect access
(pre-increment) - PREINCn
• Use the value in the WREG register as an offset
to FSRn. Do not modify the value of the WREG or
the FSRn register after an indirect access (no
change) - PLUSWn
When using the auto-increment or auto-decrement features,
the effect on the FSR is not reflected in the
STATUS register. For example, if the indirect address
causes the FSR to equal '0', the Z bit will not be set.
Incrementing or decrementing an FSR affects all 12
bits. That is, when FSRnL overflows from an increment,
FSRnH will be incremented automatically.
Adding these features allows the FSRn to be used as a
stack pointer, in addition to its uses for table operations
in data memory.
Each FSR has an address associated with it that performs
an indexed indirect access. When a data access
to this INDFn location (PLUSWn) occurs, the FSRn is
configured to add the signed value in the WREG register
and the value in FSR to form the address before an
indirect access. The FSR value is not changed.
If an FSR register contains a value that points to one of
the INDFn, an indirect read will read 00h (zero bit is
set), while an indirect write will be equivalent to a NOP
(STATUS bits are not affected).
If an indirect addressing operation is done where the
target address is an FSRnH or FSRnL register, the
write operation will dominate over the pre- or
post-increment/decrement functions.
LFSR FSR0 ,0x100 ;
NEXT CLRF POSTINC0 ; Clear INDF
; register and
; inc pointer
BTFSS FSR0H, 1 ; All done with
; Bank1?
GOTO NEXT ; NO, clear next
CONTINUE ; YES, continue © 2006 Microchip Technology Inc. DS39564C-page 51
PIC18FXX2
FIGURE 4-9: INDIRECT ADDRESSING OPERATION
FIGURE 4-10: INDIRECT ADDRESSING
Opcode Address
File Address = access of an indirect addressing register
FSR
Instruction
Executed
Instruction
Fetched
RAM
Opcode File
12 12
12
BSR<3:0>
4 8
0h
FFFh
Note 1: For register file map detail, see Table 4-1.
Data
Memory(1)
Indirect Addressing
11 FSR Register 0
0FFFh
0000h
Location SelectPIC18FXX2
DS39564C-page 52 © 2006 Microchip Technology Inc.
4.13 STATUS Register
The STATUS register, shown in Register 4-2, contains
the arithmetic status of the ALU. The STATUS register
can be the destination for any instruction, as with any
other register. If the STATUS register is the destination
for an instruction that affects the Z, DC, C, OV, or N bits,
then the write to these five bits is disabled. These bits
are set or cleared according to the device logic. Therefore,
the result of an instruction with the STATUS
register as destination may be different than intended.
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF, MOVFF and MOVWF instructions are used to
alter the STATUS register, because these instructions
do not affect the Z, C, DC, OV, or N bits from the
STATUS register. For other instructions not affecting
any status bits, see Table 20-2.
REGISTER 4-2: STATUS REGISTER
Note: The C and DC bits operate as a borrow and
digit borrow bit respectively, in subtraction.
U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x
— — — N OV Z DC C
bit 7 bit 0
bit 7-5 Unimplemented: Read as '0'
bit 4 N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1 = Result was negative
0 = Result was positive
bit 3 OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude, which causes the sign bit (bit7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
bit 2 Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1 DC: Digit carry/borrow bit
For ADDWF, ADDLW, SUBLW, and SUBWF instructions
1 = A carry-out from the 4th low order bit of the result occurred
0 = No carry-out from the 4th low order bit of the result
Note: For borrow, the polarity is reversed. A subtraction is executed by adding the two’s
complement of the second operand. For rotate (RRF, RLF) instructions, this bit is
loaded with either the bit 4 or bit 3 of the source register.
bit 0 C: Carry/borrow bit
For ADDWF, ADDLW, SUBLW, and SUBWF instructions
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note: For borrow, the polarity is reversed. A subtraction is executed by adding the two’s
complement of the second operand. For rotate (RRF, RLF) instructions, this bit is
loaded with either the high or low order bit of the source register.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 53
PIC18FXX2
4.14 RCON Register
The Reset Control (RCON) register contains flag bits
that allow differentiation between the sources of a
device RESET. These flags include the TO, PD, POR,
BOR and RI bits. This register is readable and writable.
REGISTER 4-3: RCON REGISTER
Note 1: If the BOREN configuration bit is set
(Brown-out Reset enabled), the BOR bit is
’1’ on a Power-on Reset. After a Brownout
Reset has occurred, the BOR bit will
be cleared, and must be set by firmware to
indicate the occurrence of the next
Brown-out Reset.
2: It is recommended that the POR bit be set
after a Power-on Reset has been
detected, so that subsequent Power-on
Resets may be detected.
R/W-0 U-0 U-0 R/W-1 R-1 R-1 R/W-0 R/W-0
IPEN — — RI TO PD POR BOR
bit 7 bit 0
bit 7 IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (16CXXX Compatibility mode)
bit 6-5 Unimplemented: Read as '0'
bit 4 RI: RESET Instruction Flag bit
1 = The RESET instruction was not executed
0 = The RESET instruction was executed causing a device RESET
(must be set in software after a Brown-out Reset occurs)
bit 3 TO: Watchdog Time-out Flag bit
1 = After power-up, CLRWDT instruction, or SLEEP instruction
0 = A WDT time-out occurred
bit 2 PD: Power-down Detection Flag bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 1 POR: Power-on Reset Status bit
1 = A Power-on Reset has not occurred
0 = A Power-on Reset occurred
(must be set in software after a Power-on Reset occurs)
bit 0 BOR: Brown-out Reset Status bit
1 = A Brown-out Reset has not occurred
0 = A Brown-out Reset occurred
(must be set in software after a Brown-out Reset occurs)
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 54 © 2006 Microchip Technology Inc.
NOTES: © 2006 Microchip Technology Inc. DS39564C-page 55
PIC18FXX2
5.0 FLASH PROGRAM MEMORY
The FLASH Program Memory is readable, writable,
and erasable during normal operation over the entire
VDD range.
A read from program memory is executed on one byte
at a time. A write to program memory is executed on
blocks of 8 bytes at a time. Program memory is erased
in blocks of 64 bytes at a time. A bulk erase operation
may not be issued from user code.
Writing or erasing program memory will cease instruction
fetches until the operation is complete. The program
memory cannot be accessed during the write or
erase, therefore, code cannot execute. An internal programming
timer terminates program memory writes
and erases.
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
5.1 Table Reads and Table Writes
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data
RAM:
• Table Read (TBLRD)
• Table Write (TBLWT)
The program memory space is 16-bits wide, while the
data RAM space is 8-bits wide. Table Reads and Table
Writes move data between these two memory spaces
through an 8-bit register (TABLAT).
Table Read operations retrieve data from program
memory and places it into the data RAM space.
Figure 5-1 shows the operation of a Table Read with
program memory and data RAM.
Table Write operations store data from the data memory
space into holding registers in program memory.
The procedure to write the contents of the holding registers
into program memory is detailed in Section 5.5,
'”Writing to FLASH Program Memory”. Figure 5-2
shows the operation of a Table Write with program
memory and data RAM.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word aligned. Therefore, a table block
can start and end at any byte address. If a Table Write
is being used to write executable code into program
memory, program instructions will need to be word
aligned.
FIGURE 5-1: TABLE READ OPERATION
Table Pointer(1)
Table Latch (8-bit)
Program Memory
TBLPTRH TBLPTRL
TABLAT
TBLPTRU
Instruction: TBLRD*
Note 1: Table Pointer points to a byte in program memory.
Program Memory
(TBLPTR)PIC18FXX2
DS39564C-page 56 © 2006 Microchip Technology Inc.
FIGURE 5-2: TABLE WRITE OPERATION
5.2 Control Registers
Several control registers are used in conjunction with
the TBLRD and TBLWT instructions. These include the:
• EECON1 register
• EECON2 register
• TABLAT register
• TBLPTR registers
5.2.1 EECON1 AND EECON2 REGISTERS
EECON1 is the control register for memory accesses.
EECON2 is not a physical register. Reading EECON2
will read all '0's. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit EEPGD determines if the access will be a
program or data EEPROM memory access. When
clear, any subsequent operations will operate on the
data EEPROM memory. When set, any subsequent
operations will operate on the program memory.
Control bit CFGS determines if the access will be to the
configuration registers or to program memory/data
EEPROM memory. When set, subsequent operations
will operate on configuration registers, regardless of
EEPGD (see “Special Features of the CPU”,
Section 19.0). When clear, memory selection access is
determined by EEPGD.
The FREE bit, when set, will allow a program memory
erase operation. When the FREE bit is set, the erase
operation is initiated on the next WR command. When
FREE is clear, only writes are enabled.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
Reset or a WDT Time-out Reset during normal operation.
In these situations, the user can check the
WRERR bit and rewrite the location. It is necessary to
reload the data and address registers (EEDATA and
EEADR), due to RESET values of zero.
Control bit WR initiates write operations. This bit cannot
be cleared, only set, in software. It is cleared in hardware
at the completion of the write operation. The
inability to clear the WR bit in software prevents the
accidental or premature termination of a write
operation.
Table Pointer(1) Table Latch (8-bit)
TBLPTRH TBLPTRL TABLAT
Program Memory
(TBLPTR)
TBLPTRU
Instruction: TBLWT*
Note 1: Table Pointer actually points to one of eight holding registers, the address of which is determined by
TBLPTRL<2:0>. The process for physically writing data to the Program Memory Array is discussed in
Section 5.5.
Holding Registers
Program Memory
Note: Interrupt flag bit EEIF, in the PIR2 register,
is set when the write is complete. It must
be cleared in software.© 2006 Microchip Technology Inc. DS39564C-page 57
PIC18FXX2
REGISTER 5-1: EECON1 REGISTER (ADDRESS FA6h)
R/W-x R/W-x U-0 R/W-0 R/W-x R/W-0 R/S-0 R/S-0
EEPGD CFGS — FREE WRERR WREN WR RD
bit 7 bit 0
bit 7 EEPGD: FLASH Program or Data EEPROM Memory Select bit
1 = Access FLASH Program memory
0 = Access Data EEPROM memory
bit 6 CFGS: FLASH Program/Data EE or Configuration Select bit
1 = Access Configuration registers
0 = Access FLASH Program or Data EEPROM memory
bit 5 Unimplemented: Read as '0'
bit 4 FREE: FLASH Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation)
0 = Perform write only
bit 3 WRERR: FLASH Program/Data EE Error Flag bit
1 = A write operation is prematurely terminated
(any RESET during self-timed programming in normal operation)
0 = The write operation completed
Note: When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows
tracing of the error condition.
bit 2 WREN: FLASH Program/Data EE Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the EEPROM
bit 1 WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle.
(The operation is self timed and the bit is cleared by hardware once write is complete. The
WR bit can only be set (not cleared) in software.)
0 = Write cycle to the EEPROM is complete
bit 0 RD: Read Control bit
1 = Initiates an EEPROM read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared)
in software. RD bit cannot be set when EEPGD = 1.)
0 = Does not initiate an EEPROM read
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 58 © 2006 Microchip Technology Inc.
5.2.2 TABLAT - TABLE LATCH REGISTER
The Table Latch (TABLAT) is an 8-bit register mapped
into the SFR space. The Table Latch is used to hold
8-bit data during data transfers between program
memory and data RAM.
5.2.3 TBLPTR - TABLE POINTER
REGISTER
The Table Pointer (TBLPTR) addresses a byte within
the program memory. The TBLPTR is comprised of
three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three registers
join to form a 22-bit wide pointer. The low order 21
bits allow the device to address up to 2 Mbytes of program
memory space. The 22nd bit allows access to the
Device ID, the User ID and the Configuration bits.
The table pointer, TBLPTR, is used by the TBLRD and
TBLWT instructions. These instructions can update the
TBLPTR in one of four ways based on the table operation.
These operations are shown in Table 5-1. These
operations on the TBLPTR only affect the low order
21 bits.
5.2.4 TABLE POINTER BOUNDARIES
TBLPTR is used in reads, writes, and erases of the
FLASH program memory.
When a TBLRD is executed, all 22 bits of the Table
Pointer determine which byte is read from program
memory into TABLAT.
When a TBLWT is executed, the three LSbs of the Table
Pointer (TBLPTR<2:0>) determine which of the eight
program memory holding registers is written to. When
the timed write to program memory (long write) begins,
the 19 MSbs of the Table Pointer, TBLPTR
(TBLPTR<21:3>), will determine which program memory
block of 8 bytes is written to. For more detail, see
Section 5.5 (“Writing to FLASH Program Memory”).
When an erase of program memory is executed, the 16
MSbs of the Table Pointer (TBLPTR<21:6>) point to the
64-byte block that will be erased. The Least Significant
bits (TBLPTR<5:0>) are ignored.
Figure 5-3 describes the relevant boundaries of
TBLPTR based on FLASH program memory
operations.
TABLE 5-1: TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
FIGURE 5-3: TABLE POINTER BOUNDARIES BASED ON OPERATION
Example Operation on Table Pointer
TBLRD*
TBLWT*
TBLPTR is not modified
TBLRD*+
TBLWT*+
TBLPTR is incremented after the read/write
TBLRD*-
TBLWT*-
TBLPTR is decremented after the read/write
TBLRD+*
TBLWT+*
TBLPTR is incremented before the read/write
21 16 15 8 7 0
ERASE - TBLPTR<21:6>
WRITE - TBLPTR<21:3>
READ - TBLPTR<21:0>
TBLPTRU TBLPTRH TBLPTRL© 2006 Microchip Technology Inc. DS39564C-page 59
PIC18FXX2
5.3 Reading the FLASH Program
Memory
The TBLRD instruction is used to retrieve data from program
memory and place into data RAM. Table Reads
from program memory are performed one byte at a
time.
TBLPTR points to a byte address in program space.
Executing TBLRD places the byte pointed to into
TABLAT. In addition, TBLPTR can be modified
automatically for the next Table Read operation.
The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word. Figure 5-4
shows the interface between the internal program
memory and the TABLAT.
FIGURE 5-4: READS FROM FLASH PROGRAM MEMORY
EXAMPLE 5-1: READING A FLASH PROGRAM MEMORY WORD
(Even Byte Address)
Program Memory
(Odd Byte Address)
TBLRD TABLAT
TBLPTR = xxxxx1
FETCH Instruction Register
(IR) Read Register
TBLPTR = xxxxx0
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base
MOVWF TBLPTRU ; address of the word
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
READ_WORD
TBLRD*+ ; read into TABLAT and increment
MOVF TABLAT, W ; get data
MOVWF WORD_EVEN
TBLRD*+ ; read into TABLAT and increment
MOVF TABLAT, W ; get data
MOVWF WORD_ODDPIC18FXX2
DS39564C-page 60 © 2006 Microchip Technology Inc.
5.4 Erasing FLASH Program memory
The minimum erase block is 32 words or 64 bytes. Only
through the use of an external programmer, or through
ICSP control can larger blocks of program memory be
bulk erased. Word erase in the FLASH array is not
supported.
When initiating an erase sequence from the microcontroller
itself, a block of 64 bytes of program memory
is erased. The Most Significant 16 bits of the
TBLPTR<21:6> point to the block being erased.
TBLPTR<5:0> are ignored.
The EECON1 register commands the erase operation.
The EEPGD bit must be set to point to the FLASH program
memory. The WREN bit must be set to enable
write operations. The FREE bit is set to select an erase
operation.
For protection, the write initiate sequence for EECON2
must be used.
A long write is necessary for erasing the internal
FLASH. Instruction execution is halted while in a long
write cycle. The long write will be terminated by the
internal programming timer.
5.4.1 FLASH PROGRAM MEMORY
ERASE SEQUENCE
The sequence of events for erasing a block of internal
program memory location is:
1. Load table pointer with address of row being
erased.
2. Set EEPGD bit to point to program memory,
clear CFGS bit to access program memory, set
WREN bit to enable writes, and set FREE bit to
enable the erase.
3. Disable interrupts.
4. Write 55h to EECON2.
5. Write AAh to EECON2.
6. Set the WR bit. This will begin the row erase
cycle.
7. The CPU will stall for duration of the erase
(about 2 ms using internal timer).
8. Re-enable interrupts.
EXAMPLE 5-2: ERASING A FLASH PROGRAM MEMORY ROW
MOVLW CODE_ADDR_UPPER ; load TBLPTR with the base
MOVWF TBLPTRU ; address of the memory block
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
ERASE_ROW
BSF EECON1,EEPGD ; point to FLASH program memory
BCF EECON1,CFGS ; access FLASH program memory
BSF EECON1,WREN ; enable write to memory
BSF EECON1,FREE ; enable Row Erase operation
BCF INTCON,GIE ; disable interrupts
MOVLW 55h
Required MOVWF EECON2 ; write 55h
Sequence MOVLW AAh
MOVWF EECON2 ; write AAh
BSF EECON1,WR ; start erase (CPU stall)
BSF INTCON,GIE ; re-enable interrupts© 2006 Microchip Technology Inc. DS39564C-page 61
PIC18FXX2
5.5 Writing to FLASH Program
Memory
The minimum programming block is 4 words or 8 bytes.
Word or byte programming is not supported.
Table Writes are used internally to load the holding registers
needed to program the FLASH memory. There
are 8 holding registers used by the Table Writes for
programming.
Since the Table Latch (TABLAT) is only a single byte,
the TBLWT instruction has to be executed 8 times for
each programming operation. All of the Table Write
operations will essentially be short writes, because only
the holding registers are written. At the end of updating
8 registers, the EECON1 register must be written to, to
start the programming operation with a long write.
The long write is necessary for programming the internal
FLASH. Instruction execution is halted while in a
long write cycle. The long write will be terminated by
the internal programming timer.
The EEPROM on-chip timer controls the write time.
The write/erase voltages are generated by an on-chip
charge pump rated to operate over the voltage range of
the device for byte or word operations.
FIGURE 5-5: TABLE WRITES TO FLASH PROGRAM MEMORY
5.5.1 FLASH PROGRAM MEMORY WRITE
SEQUENCE
The sequence of events for programming an internal
program memory location should be:
1. Read 64 bytes into RAM.
2. Update data values in RAM as necessary.
3. Load Table Pointer with address being erased.
4. Do the row erase procedure.
5. Load Table Pointer with address of first byte
being written.
6. Write the first 8 bytes into the holding registers
with auto-increment (TBLWT*+ or TBLWT+*).
7. Set EEPGD bit to point to program memory,
clear the CFGS bit to access program memory,
and set WREN to enable byte writes.
8. Disable interrupts.
9. Write 55h to EECON2.
10. Write AAh to EECON2.
11. Set the WR bit. This will begin the write cycle.
12. The CPU will stall for duration of the write (about
2 ms using internal timer).
13. Re-enable interrupts.
14. Repeat steps 6-14 seven times, to write
64 bytes.
15. Verify the memory (Table Read).
This procedure will require about 18 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 5-3.
Holding Register
TABLAT
Holding Register
TBLPTR = xxxxx7
Holding Register
TBLPTR = xxxxx1
Holding Register
TBLPTR = xxxxx0
8 8 8 8
Write Register
TBLPTR = xxxxx2
Program Memory
Note: Before setting the WR bit, the table pointer
address needs to be within the intended
address range of the 8 bytes in the holding
registers.PIC18FXX2
DS39564C-page 62 © 2006 Microchip Technology Inc.
EXAMPLE 5-3: WRITING TO FLASH PROGRAM MEMORY
MOVLW D'64 ; number of bytes in erase block
MOVWF COUNTER
MOVLW BUFFER_ADDR_HIGH ; point to buffer
MOVWF FSR0H
MOVLW BUFFER_ADDR_LOW
MOVWF FSR0L
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base
MOVWF TBLPTRU ; address of the memory block
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
READ_BLOCK
TBLRD*+ ; read into TABLAT, and inc
MOVF TABLAT, W ; get data
MOVWF POSTINC0 ; store data
DECFSZ COUNTER ; done?
BRA READ_BLOCK ; repeat
MODIFY_WORD
MOVLW DATA_ADDR_HIGH ; point to buffer
MOVWF FSR0H
MOVLW DATA_ADDR_LOW
MOVWF FSR0L
MOVLW NEW_DATA_LOW ; update buffer word
MOVWF POSTINC0
MOVLW NEW_DATA_HIGH
MOVWF INDF0
ERASE_BLOCK
MOVLW CODE_ADDR_UPPER ; load TBLPTR with the base
MOVWF TBLPTRU ; address of the memory block
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
BSF EECON1,EEPGD ; point to FLASH program memory
BCF EECON1,CFGS ; access FLASH program memory
BSF EECON1,WREN ; enable write to memory
BSF EECON1,FREE ; enable Row Erase operation
BCF INTCON,GIE ; disable interrupts
MOVLW 55h
MOVWF EECON2 ; write 55h
MOVLW AAh
MOVWF EECON2 ; write AAh
BSF EECON1,WR ; start erase (CPU stall)
BSF INTCON,GIE ; re-enable interrupts
TBLRD*- ; dummy read decrement
WRITE_BUFFER_BACK
MOVLW 8 ; number of write buffer groups of 8 bytes
MOVWF COUNTER_HI
MOVLW BUFFER_ADDR_HIGH ; point to buffer
MOVWF FSR0H
MOVLW BUFFER_ADDR_LOW
MOVWF FSR0L
PROGRAM_LOOP
MOVLW 8 ; number of bytes in holding register
MOVWF COUNTER
WRITE_WORD_TO_HREGS
MOVF POSTINC0, W ; get low byte of buffer data
MOVWF TABLAT ; present data to table latch
TBLWT+* ; write data, perform a short write
; to internal TBLWT holding register.
DECFSZ COUNTER ; loop until buffers are full
BRA WRITE_WORD_TO_HREGS© 2006 Microchip Technology Inc. DS39564C-page 63
PIC18FXX2
EXAMPLE 5-3: WRITING TO FLASH PROGRAM MEMORY (CONTINUED)
5.5.2 WRITE VERIFY
Depending on the application, good programming
practice may dictate that the value written to the memory
should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
5.5.3 UNEXPECTED TERMINATION OF
WRITE OPERATION
If a write is terminated by an unplanned event, such as
loss of power or an unexpected RESET, the memory
location just programmed should be verified and reprogrammed
if needed.The WRERR bit is set when a write
operation is interrupted by a MCLR Reset, or a WDT
Time-out Reset during normal operation. In these situations,
users can check the WRERR bit and rewrite the
location.
5.5.4 PROTECTION AGAINST SPURIOUS
WRITES
To protect against spurious writes to FLASH program
memory, the write initiate sequence must also be followed.
See “Special Features of the CPU”
(Section 19.0) for more detail.
5.6 FLASH Program Operation During
Code Protection
See “Special Features of the CPU” (Section 19.0) for
details on code protection of FLASH program memory.
TABLE 5-2: REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY
PROGRAM_MEMORY
BSF EECON1,EEPGD ; point to FLASH program memory
BCF EECON1,CFGS ; access FLASH program memory
BSF EECON1,WREN ; enable write to memory
BCF INTCON,GIE ; disable interrupts
MOVLW 55h
Required MOVWF EECON2 ; write 55h
Sequence MOVLW AAh
MOVWF EECON2 ; write AAh
BSF EECON1,WR ; start program (CPU stall)
BSF INTCON,GIE ; re-enable interrupts
DECFSZ COUNTER_HI ; loop until done
BRA PROGRAM_LOOP
BCF EECON1,WREN ; disable write to memory
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on
All Other
RESETS
FF8h TBLPTRU — — bit21 Program Memory Table Pointer Upper Byte
(TBLPTR<20:16>)
--00 0000 --00 0000
FF7h TBPLTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>) 0000 0000 0000 0000
FF6h TBLPTRL Program Memory Table Pointer High Byte (TBLPTR<7:0>) 0000 0000 0000 0000
FF5h TABLAT Program Memory Table Latch 0000 0000 0000 0000
FF2h INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
FA7h EECON2 EEPROM Control Register2 (not a physical register) — —
FA6h EECON1 EEPGD CFGS — FREE WRERR WREN WR RD xx-0 x000 uu-0 u000
FA2h IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 ---1 1111
FA1h PIR2 — — — EEIF BCLIF LVDIF TMR3IF CCP2IF ---0 0000 ---0 0000
FA0h PIE2 — — — EEIE BCLIE LVDIE TMR3IE CCP2IE ---0 0000 ---0 0000
Legend: x = unknown, u = unchanged, r = reserved, - = unimplemented read as '0'.
Shaded cells are not used during FLASH/EEPROM access.PIC18FXX2
DS39564C-page 64 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 65
PIC18FXX2
6.0 DATA EEPROM MEMORY
The Data EEPROM is readable and writable during
normal operation over the entire VDD range. The data
memory is not directly mapped in the register file
space. Instead, it is indirectly addressed through the
Special Function Registers (SFR).
There are four SFRs used to read and write the
program and data EEPROM memory. These registers
are:
• EECON1
• EECON2
• EEDATA
• EEADR
The EEPROM data memory allows byte read and write.
When interfacing to the data memory block, EEDATA
holds the 8-bit data for read/write and EEADR holds the
address of the EEPROM location being accessed.
These devices have 256 bytes of data EEPROM with
an address range from 0h to FFh.
The EEPROM data memory is rated for high erase/
write cycles. A byte write automatically erases the location
and writes the new data (erase-before-write). The
write time is controlled by an on-chip timer. The write
time will vary with voltage and temperature, as well as
from chip to chip. Please refer to parameter D122
(Electrical Characteristics, Section 22.0) for exact
limits.
6.1 EEADR
The address register can address up to a maximum of
256 bytes of data EEPROM.
6.2 EECON1 and EECON2 Registers
EECON1 is the control register for EEPROM memory
accesses.
EECON2 is not a physical register. Reading EECON2
will read all '0's. The EECON2 register is used
exclusively in the EEPROM write sequence.
Control bits RD and WR initiate read and write operations,
respectively. These bits cannot be cleared, only
set, in software. They are cleared in hardware at the
completion of the read or write operation. The inability
to clear the WR bit in software prevents the accidental
or premature termination of a write operation.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
Reset, or a WDT Time-out Reset during normal operation.
In these situations, the user can check the
WRERR bit and rewrite the location. It is necessary to
reload the data and address registers (EEDATA and
EEADR), due to the RESET condition forcing the
contents of the registers to zero.
Note: Interrupt flag bit, EEIF in the PIR2 register,
is set when write is complete. It must be
cleared in software.PIC18FXX2
DS39564C-page 66 © 2006 Microchip Technology Inc.
REGISTER 6-1: EECON1 REGISTER (ADDRESS FA6h)
R/W-x R/W-x U-0 R/W-0 R/W-x R/W-0 R/S-0 R/S-0
EEPGD CFGS — FREE WRERR WREN WR RD
bit 7 bit 0
bit 7 EEPGD: FLASH Program or Data EEPROM Memory Select bit
1 = Access FLASH Program memory
0 = Access Data EEPROM memory
bit 6 CFGS: FLASH Program/Data EE or Configuration Select bit
1 = Access Configuration or Calibration registers
0 = Access FLASH Program or Data EEPROM memory
bit 5 Unimplemented: Read as '0'
bit 4 FREE: FLASH Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation)
0 = Perform write only
bit 3 WRERR: FLASH Program/Data EE Error Flag bit
1 = A write operation is prematurely terminated
(any MCLR or any WDT Reset during self-timed programming in normal operation)
0 = The write operation completed
Note: When a WRERR occurs, the EEPGD or FREE bits are not cleared. This allows tracing
of the error condition.
bit 2 WREN: FLASH Program/Data EE Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the EEPROM
bit 1 WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The
WR bit can only be set (not cleared) in software.)
0 = Write cycle to the EEPROM is complete
bit 0 RD: Read Control bit
1 = Initiates an EEPROM read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared)
in software. RD bit cannot be set when EEPGD = 1.)
0 = Does not initiate an EEPROM read
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 67
PIC18FXX2
6.3 Reading the Data EEPROM
Memory
To read a data memory location, the user must write the
address to the EEADR register, clear the EEPGD control
bit (EECON1<7>), clear the CFGS control bit
(EECON1<6>), and then set control bit RD
(EECON1<0>). The data is available for the very next
instruction cycle; therefore, the EEDATA register can
be read by the next instruction. EEDATA will hold this
value until another read operation, or until it is written to
by the user (during a write operation).
EXAMPLE 6-1: DATA EEPROM READ
6.4 Writing to the Data EEPROM
Memory
To write an EEPROM data location, the address must
first be written to the EEADR register and the data written
to the EEDATA register. Then the sequence in
Example 6-2 must be followed to initiate the write cycle.
The write will not initiate if the above sequence is not
exactly followed (write 55h to EECON2, write AAh to
EECON2, then set WR bit) for each byte. It is strongly
recommended that interrupts be disabled during this
code segment.
Additionally, the WREN bit in EECON1 must be set to
enable writes. This mechanism prevents accidental
writes to data EEPROM due to unexpected code execution
(i.e., runaway programs). The WREN bit should
be kept clear at all times, except when updating the
EEPROM. The WREN bit is not cleared by hardware.
After a write sequence has been initiated, EECON1,
EEADR and EDATA cannot be modified. The WR bit
will be inhibited from being set unless the WREN bit is
set. The WREN bit must be set on a previous instruction.
Both WR and WREN cannot be set with the same
instruction.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EEPROM Write Complete
Interrupt Flag bit (EEIF) is set. The user may either
enable this interrupt, or poll this bit. EEIF must be
cleared by software.
EXAMPLE 6-2: DATA EEPROM WRITE
MOVLW DATA_EE_ADDR ;
MOVWF EEADR ; Data Memory Address to read
BCF EECON1, EEPGD ; Point to DATA memory
BCF EECON1, CFGS ; Access program FLASH or Data EEPROM memory
BSF EECON1, RD ; EEPROM Read
MOVF EEDATA, W ; W = EEDATA
MOVLW DATA_EE_ADDR ;
MOVWF EEADR ; Data Memory Address to read
MOVLW DATA_EE_DATA ;
MOVWF EEDATA ; Data Memory Value to write
BCF EECON1, EEPGD ; Point to DATA memory
BCF EECON1, CFGS ; Access program FLASH or Data EEPROM memory
BSF EECON1, WREN ; Enable writes
BCF INTCON, GIE ; Disable interrupts
Required MOVLW 55h ;
Sequence MOVWF EECON2 ; Write 55h
MOVLW AAh ;
MOVWF EECON2 ; Write AAh
BSF EECON1, WR ; Set WR bit to begin write
BSF INTCON, GIE ; Enable interrupts
. ; user code execution
.
.
BCF EECON1, WREN ; Disable writes on write complete (EEIF set)PIC18FXX2
DS39564C-page 68 © 2006 Microchip Technology Inc.
6.5 Write Verify
Depending on the application, good programming
practice may dictate that the value written to the memory
should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
6.6 Protection Against Spurious Write
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built-in. On power-up, the WREN bit is cleared.
Also, the Power-up Timer (72 ms duration) prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch, or software malfunction.
6.7 Operation During Code Protect
Data EEPROM memory has its own code protect
mechanism. External Read and Write operations are
disabled if either of these mechanisms are enabled.
The microcontroller itself can both read and write to the
internal Data EEPROM, regardless of the state of the
code protect configuration bit. Refer to “Special Features
of the CPU” (Section 19.0) for additional information.
6.8 Using the Data EEPROM
The data EEPROM is a high endurance, byte addressable
array that has been optimized for the storage of
frequently changing information (e.g., program variables
or other data that are updated often). Frequently
changing values will typically be updated more often
than specification D124. If this is not the case, an array
refresh must be performed. For this reason, variables
that change infrequently (such as constants, IDs, calibration,
etc.) should be stored in FLASH program
memory.
A simple data EEPROM refresh routine is shown in
Example 6-3.
EXAMPLE 6-3: DATA EEPROM REFRESH ROUTINE
Note: If data EEPROM is only used to store constants
and/or data that changes rarely, an
array refresh is likely not required. See
specification D124.
clrf EEADR ; Start at address 0
bcf EECON1,CFGS ; Set for memory
bcf EECON1,EEPGD ; Set for Data EEPROM
bcf INTCON,GIE ; Disable interrupts
bsf EECON1,WREN ; Enable writes
Loop ; Loop to refresh array
bsf EECON1,RD ; Read current address
movlw 55h ;
movwf EECON2 ; Write 55h
movlw AAh ;
movwf EECON2 ; Write AAh
bsf EECON1,WR ; Set WR bit to begin write
btfsc EECON1,WR ; Wait for write to complete
bra $-2
incfsz EEADR,F ; Increment address
bra Loop ; Not zero, do it again
bcf EECON1,WREN ; Disable writes
bsf INTCON,GIE ; Enable interrupts© 2006 Microchip Technology Inc. DS39564C-page 69
PIC18FXX2
TABLE 6-1: REGISTERS ASSOCIATED WITH DATA EEPROM MEMORY
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on
All Other
RESETS
FF2h INTCON GIE/
GIEH
PEIE/
GIEL
T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u
FA9h EEADR EEPROM Address Register 0000 0000 0000 0000
FA8h EEDATA EEPROM Data Register 0000 0000 0000 0000
FA7h EECON2 EEPROM Control Register2 (not a physical register) — —
FA6h EECON1 EEPGD CFGS — FREE WRERR WREN WR RD xx-0 x000 uu-0 u000
FA2h IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 ---1 1111
FA1h PIR2 — — — EEIF BCLIF LVDIF TMR3IF CCP2IF ---0 0000 ---0 0000
FA0h PIE2 — — — EEIE BCLIE LVDIE TMR3IE CCP2IE ---0 0000 ---0 0000
Legend: x = unknown, u = unchanged, r = reserved, - = unimplemented, read as '0'.
Shaded cells are not used during FLASH/EEPROM access.PIC18FXX2
DS39564C-page 70 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 71
PIC18FXX2
7.0 8 X 8 HARDWARE MULTIPLIER
7.1 Introduction
An 8 x 8 hardware multiplier is included in the ALU of
the PIC18FXX2 devices. By making the multiply a
hardware operation, it completes in a single instruction
cycle. This is an unsigned multiply that gives a 16-bit
result. The result is stored into the 16-bit product register
pair (PRODH:PRODL). The multiplier does not
affect any flags in the ALUSTA register.
Making the 8 x 8 multiplier execute in a single cycle
gives the following advantages:
• Higher computational throughput
• Reduces code size requirements for multiply
algorithms
The performance increase allows the device to be used
in applications previously reserved for Digital Signal
Processors.
Table 7-1 shows a performance comparison between
enhanced devices using the single cycle hardware multiply,
and performing the same function without the
hardware multiply.
TABLE 7-1: PERFORMANCE COMPARISON
7.2 Operation
Example 7-1 shows the sequence to do an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
Example 7-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s Most Significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 7-1: 8 x 8 UNSIGNED
MULTIPLY ROUTINE
EXAMPLE 7-2: 8 x 8 SIGNED MULTIPLY
ROUTINE
Example 7-3 shows the sequence to do a 16 x 16
unsigned multiply. Equation 7-1 shows the algorithm
that is used. The 32-bit result is stored in four registers,
RES3:RES0.
EQUATION 7-1: 16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
Routine Multiply Method
Program
Memory
(Words)
Cycles
(Max)
Time
@ 40 MHz @ 10 MHz @ 4 MHz
8 x 8 unsigned Without hardware multiply 13 69 6.9 μs 27.6 μs 69 μs
Hardware multiply 1 1 100 ns 400 ns 1 μs
8 x 8 signed Without hardware multiply 33 91 9.1 μs 36.4 μs 91 μs
Hardware multiply 6 6 600 ns 2.4 μs 6 μs
16 x 16 unsigned Without hardware multiply 21 242 24.2 μs 96.8 μs 242 μs
Hardware multiply 24 24 2.4 μs 9.6 μs 24 μs
16 x 16 signed Without hardware multiply 52 254 25.4 μs 102.6 μs 254 μs
Hardware multiply 36 36 3.6 μs 14.4 μs 36 μs
MOVF ARG1, W ;
MULWF ARG2 ; ARG1 * ARG2 ->
; PRODH:PRODL
MOVF ARG1, W
MULWF ARG2 ; ARG1 * ARG2 ->
; PRODH:PRODL
BTFSC ARG2, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH
; - ARG1
MOVF ARG2, W
BTFSC ARG1, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH
; - ARG2
RES3:RES0 = ARG1H:ARG1L • ARG2H:ARG2L
= (ARG1H • ARG2H • 216) +
(ARG1H • ARG2L • 28
) +
(ARG1L • ARG2H • 28) +
(ARG1L • ARG2L)PIC18FXX2
DS39564C-page 72 © 2006 Microchip Technology Inc.
EXAMPLE 7-3: 16 x 16 UNSIGNED
MULTIPLY ROUTINE
Example 7-4 shows the sequence to do a 16 x 16
signed multiply. Equation 7-2 shows the algorithm
used. The 32-bit result is stored in four registers,
RES3:RES0. To account for the sign bits of the arguments,
each argument pairs Most Significant bit (MSb)
is tested and the appropriate subtractions are done.
EQUATION 7-2: 16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
EXAMPLE 7-4: 16 x 16 SIGNED
MULTIPLY ROUTINE
MOVF ARG1L, W
MULWF ARG2L ; ARG1L * ARG2L ->
; PRODH:PRODL
MOVFF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W
MULWF ARG2H ; ARG1H * ARG2H ->
; PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
RES3:RES0
= ARG1H:ARG1L • ARG2H:ARG2L
= (ARG1H • ARG2H • 216) +
(ARG1H • ARG2L • 28) +
(ARG1L • ARG2H • 28) +
(ARG1L • ARG2L) +
(-1 • ARG2H<7> • ARG1H:ARG1L • 216) +
(-1 • ARG1H<7> • ARG2H:ARG2L • 216)
MOVF ARG1L, W
MULWF ARG2L ; ARG1L * ARG2L ->
; PRODH:PRODL
MOVFF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W
MULWF ARG2H ; ARG1H * ARG2H ->
; PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
BTFSS ARG2H, 7 ; ARG2H:ARG2L neg?
BRA SIGN_ARG1 ; no, check ARG1
MOVF ARG1L, W ;
SUBWF RES2 ;
MOVF ARG1H, W ;
SUBWFB RES3
;
SIGN_ARG1
BTFSS ARG1H, 7 ; ARG1H:ARG1L neg?
BRA CONT_CODE ; no, done
MOVF ARG2L, W ;
SUBWF RES2 ;
MOVF ARG2H, W ;
SUBWFB RES3
;
CONT_CODE
: © 2006 Microchip Technology Inc. DS39564C-page 73
PIC18FXX2
8.0 INTERRUPTS
The PIC18FXX2 devices have multiple interrupt
sources and an interrupt priority feature that allows
each interrupt source to be assigned a high priority
level or a low priority level. The high priority interrupt
vector is at 000008h and the low priority interrupt vector
is at 000018h. High priority interrupt events will override
any low priority interrupts that may be in progress.
There are ten registers which are used to control
interrupt operation. These registers are:
• RCON
• INTCON
• INTCON2
• INTCON3
• PIR1, PIR2
• PIE1, PIE2
• IPR1, IPR2
It is recommended that the Microchip header files supplied
with MPLAB® IDE be used for the symbolic bit
names in these registers. This allows the assembler/
compiler to automatically take care of the placement of
these bits within the specified register.
Each interrupt source, except INT0, has three bits to
control its operation. The functions of these bits are:
• Flag bit to indicate that an interrupt event
occurred
• Enable bit that allows program execution to
branch to the interrupt vector address when the
flag bit is set
• Priority bit to select high priority or low priority
The interrupt priority feature is enabled by setting the
IPEN bit (RCON<7>). When interrupt priority is
enabled, there are two bits which enable interrupts globally.
Setting the GIEH bit (INTCON<7>) enables all
interrupts that have the priority bit set. Setting the GIEL
bit (INTCON<6>) enables all interrupts that have the
priority bit cleared. When the interrupt flag, enable bit
and appropriate global interrupt enable bit are set, the
interrupt will vector immediately to address 000008h or
000018h, depending on the priority level. Individual
interrupts can be disabled through their corresponding
enable bits.
When the IPEN bit is cleared (default state), the interrupt
priority feature is disabled and interrupts are compatible
with PICmicro® mid-range devices. In
Compatibility mode, the interrupt priority bits for each
source have no effect. INTCON<6> is the PEIE bit,
which enables/disables all peripheral interrupt sources.
INTCON<7> is the GIE bit, which enables/disables all
interrupt sources. All interrupts branch to address
000008h in Compatibility mode.
When an interrupt is responded to, the Global Interrupt
Enable bit is cleared to disable further interrupts. If the
IPEN bit is cleared, this is the GIE bit. If interrupt priority
levels are used, this will be either the GIEH or GIEL bit.
High priority interrupt sources can interrupt a low
priority interrupt.
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address
(000008h or 000018h). Once in the Interrupt Service
Routine, the source(s) of the interrupt can be determined
by polling the interrupt flag bits. The interrupt
flag bits must be cleared in software before re-enabling
interrupts to avoid recursive interrupts.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE bit (GIEH or GIEL
if priority levels are used), which re-enables interrupts.
For external interrupt events, such as the INT pins or
the PORTB input change interrupt, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one or two-cycle instructions.
Individual interrupt flag bits are set, regardless of the
status of their corresponding enable bit or the GIE bit.
Note: Do not use the MOVFF instruction to modify
any of the Interrupt control registers while
any interrupt is enabled. Doing so may
cause erratic microcontroller behavior.PIC18FXX2
DS39564C-page 74 © 2006 Microchip Technology Inc.
FIGURE 8-1: INTERRUPT LOGIC
TMR0IE
GIEH/GIE
GIEL/PEIE
Wake-up if in SLEEP mode
Interrupt to CPU
Vector to location
0008h
INT2IF
INT2IE
INT2IP
INT1IF
INT1IE
INT1IP
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
IPEN
TMR0IF
TMR0IP
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
GIEL/PEIE
Interrupt to CPU
Vector to Location
IPEN
IPE
0018h
Peripheral Interrupt Flag bit
Peripheral Interrupt Enable bit
Peripheral Interrupt Priority bit
Peripheral Interrupt Flag bit
Peripheral Interrupt Enable bit
Peripheral Interrupt Priority bit
TMR1IF
TMR1IE
TMR1IP
XXXXIF
XXXXIE
XXXXIP
Additional Peripheral Interrupts
TMR1IF
TMR1IE
TMR1IP
High Priority Interrupt Generation
Low Priority Interrupt Generation
XXXXIF
XXXXIE
XXXXIP
Additional Peripheral Interrupts
GIE/GIEH© 2006 Microchip Technology Inc. DS39564C-page 75
PIC18FXX2
8.1 INTCON Registers
The INTCON Registers are readable and writable registers,
which contain various enable, priority and flag
bits.
REGISTER 8-1: INTCON REGISTER
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit. User software should ensure
the appropriate interrupt flag bits are clear
prior to enabling an interrupt. This feature
allows for software polling.
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x
GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF
bit 7 bit 0
bit 7 GIE/GIEH: Global Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked interrupts
0 = Disables all interrupts
When IPEN = 1:
1 = Enables all high priority interrupts
0 = Disables all interrupts
bit 6 PEIE/GIEL: Peripheral Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
When IPEN = 1:
1 = Enables all low priority peripheral interrupts
0 = Disables all low priority peripheral interrupts
bit 5 TMR0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 overflow interrupt
0 = Disables the TMR0 overflow interrupt
bit 4 INT0IE: INT0 External Interrupt Enable bit
1 = Enables the INT0 external interrupt
0 = Disables the INT0 external interrupt
bit 3 RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt
bit 2 TMR0IF: TMR0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register did not overflow
bit 1 INT0IF: INT0 External Interrupt Flag bit
1 = The INT0 external interrupt occurred (must be cleared in software)
0 = The INT0 external interrupt did not occur
bit 0 RBIF: RB Port Change Interrupt Flag bit
1 = At least one of the RB7:RB4 pins changed state (must be cleared in software)
0 = None of the RB7:RB4 pins have changed state
Note: A mismatch condition will continue to set this bit. Reading PORTB will end the
mismatch condition and allow the bit to be cleared.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 76 © 2006 Microchip Technology Inc.
REGISTER 8-2: INTCON2 REGISTER
R/W-1 R/W-1 R/W-1 R/W-1 U-0 R/W-1 U-0 R/W-1
RBPU INTEDG0 INTEDG1 INTEDG2 — TMR0IP — RBIP
bit 7 bit 0
bit 7 RBPU: PORTB Pull-up Enable bit
1 = All PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values
bit 6 INTEDG0:External Interrupt0 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 5 INTEDG1: External Interrupt1 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 4 INTEDG2: External Interrupt2 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 3 Unimplemented: Read as '0'
bit 2 TMR0IP: TMR0 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 Unimplemented: Read as '0'
bit 0 RBIP: RB Port Change Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown
Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.© 2006 Microchip Technology Inc. DS39564C-page 77
PIC18FXX2
REGISTER 8-3: INTCON3 REGISTER
R/W-1 R/W-1 U-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0
INT2IP INT1IP — INT2IE INT1IE — INT2IF INT1IF
bit 7 bit 0
bit 7 INT2IP: INT2 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6 INT1IP: INT1 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5 Unimplemented: Read as '0'
bit 4 INT2IE: INT2 External Interrupt Enable bit
1 = Enables the INT2 external interrupt
0 = Disables the INT2 external interrupt
bit 3 INT1IE: INT1 External Interrupt Enable bit
1 = Enables the INT1 external interrupt
0 = Disables the INT1 external interrupt
bit 2 Unimplemented: Read as '0'
bit 1 INT2IF: INT2 External Interrupt Flag bit
1 = The INT2 external interrupt occurred (must be cleared in software)
0 = The INT2 external interrupt did not occur
bit 0 INT1IF: INT1 External Interrupt Flag bit
1 = The INT1 external interrupt occurred (must be cleared in software)
0 = The INT1 external interrupt did not occur
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown
Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global enable bit. User software should ensure
the appropriate interrupt flag bits are clear prior to enabling an interrupt. This feature
allows for software polling.PIC18FXX2
DS39564C-page 78 © 2006 Microchip Technology Inc.
8.2 PIR Registers
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Flag Registers (PIR1, PIR2).
REGISTER 8-4: PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
Note 1: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>).
2: User software should ensure the appropriate
interrupt flag bits are cleared prior to enabling
an interrupt, and after servicing that interrupt.
R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF
bit 7 bit 0
bit 7 PSPIF(1): Parallel Slave Port Read/Write Interrupt Flag bit
1 = A read or a write operation has taken place (must be cleared in software)
0 = No read or write has occurred
bit 6 ADIF: A/D Converter Interrupt Flag bit
1 = An A/D conversion completed (must be cleared in software)
0 = The A/D conversion is not complete
bit 5 RCIF: USART Receive Interrupt Flag bit
1 = The USART receive buffer, RCREG, is full (cleared when RCREG is read)
0 = The USART receive buffer is empty
bit 4 TXIF: USART Transmit Interrupt Flag bit (see Section 16.0 for details on TXIF functionality)
1 = The USART transmit buffer, TXREG, is empty (cleared when TXREG is written)
0 = The USART transmit buffer is full
bit 3 SSPIF: Master Synchronous Serial Port Interrupt Flag bit
1 = The transmission/reception is complete (must be cleared in software)
0 = Waiting to transmit/receive
bit 2 CCP1IF: CCP1 Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode
bit 1 TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1 = TMR2 to PR2 match occurred (must be cleared in software)
0 = No TMR2 to PR2 match occurred
bit 0 TMR1IF: TMR1 Overflow Interrupt Flag bit
1 = TMR1 register overflowed (must be cleared in software)
0 = MR1 register did not overflow
Note 1: This bit is reserved on PIC18F2X2 devices; always maintain this bit clear.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 79
PIC18FXX2
REGISTER 8-5: PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — EEIF BCLIF LVDIF TMR3IF CCP2IF
bit 7 bit 0
bit 7-5 Unimplemented: Read as '0'
bit 4 EEIF: Data EEPROM/FLASH Write Operation Interrupt Flag bit
1 = The Write operation is complete (must be cleared in software)
0 = The Write operation is not complete, or has not been started
bit 3 BCLIF: Bus Collision Interrupt Flag bit
1 = A bus collision occurred (must be cleared in software)
0 = No bus collision occurred
bit 2 LVDIF: Low Voltage Detect Interrupt Flag bit
1 = A low voltage condition occurred (must be cleared in software)
0 = The device voltage is above the Low Voltage Detect trip point
bit 1 TMR3IF: TMR3 Overflow Interrupt Flag bit
1 = TMR3 register overflowed (must be cleared in software)
0 = TMR3 register did not overflow
bit 0 CCP2IF: CCPx Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 80 © 2006 Microchip Technology Inc.
8.3 PIE Registers
The PIE registers contain the individual enable bits for
the peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Enable Registers (PIE1, PIE2). When IPEN = 0,
the PEIE bit must be set to enable any of these
peripheral interrupts.
REGISTER 8-6: PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE
bit 7 bit 0
bit 7 PSPIE(1): Parallel Slave Port Read/Write Interrupt Enable bit
1 = Enables the PSP read/write interrupt
0 = Disables the PSP read/write interrupt
bit 6 ADIE: A/D Converter Interrupt Enable bit
1 = Enables the A/D interrupt
0 = Disables the A/D interrupt
bit 5 RCIE: USART Receive Interrupt Enable bit
1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt
bit 4 TXIE: USART Transmit Interrupt Enable bit
1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt
bit 3 SSPIE: Master Synchronous Serial Port Interrupt Enable bit
1 = Enables the MSSP interrupt
0 = Disables the MSSP interrupt
bit 2 CCP1IE: CCP1 Interrupt Enable bit
1 = Enables the CCP1 interrupt
0 = Disables the CCP1 interrupt
bit 1 TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the TMR2 to PR2 match interrupt
0 = Disables the TMR2 to PR2 match interrupt
bit 0 TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enables the TMR1 overflow interrupt
0 = Disables the TMR1 overflow interrupt
Note 1: This bit is reserved on PIC18F2X2 devices; always maintain this bit clear.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 81
PIC18FXX2
REGISTER 8-7: PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — EEIE BCLIE LVDIE TMR3IE CCP2IE
bit 7 bit 0
bit 7-5 Unimplemented: Read as '0'
bit 4 EEIE: Data EEPROM/FLASH Write Operation Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3 BCLIE: Bus Collision Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 2 LVDIE: Low Voltage Detect Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 1 TMR3IE: TMR3 Overflow Interrupt Enable bit
1 = Enables the TMR3 overflow interrupt
0 = Disables the TMR3 overflow interrupt
bit 0 CCP2IE: CCP2 Interrupt Enable bit
1 = Enables the CCP2 interrupt
0 = Disables the CCP2 interrupt
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 82 © 2006 Microchip Technology Inc.
8.4 IPR Registers
The IPR registers contain the individual priority bits for
the peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Priority Registers (IPR1, IPR2). The operation of
the priority bits requires that the Interrupt Priority
Enable (IPEN) bit be set.
REGISTER 8-8: IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP
bit 7 bit 0
bit 7 PSPIP(1): Parallel Slave Port Read/Write Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6 ADIP: A/D Converter Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5 RCIP: USART Receive Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4 TXIP: USART Transmit Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3 SSPIP: Master Synchronous Serial Port Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2 CCP1IP: CCP1 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 TMR2IP: TMR2 to PR2 Match Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0 TMR1IP: TMR1 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
Note 1: This bit is reserved on PIC18F2X2 devices; always maintain this bit set.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 83
PIC18FXX2
REGISTER 8-9: IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
U-0 U-0 U-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
— — — EEIP BCLIP LVDIP TMR3IP CCP2IP
bit 7 bit 0
bit 7-5 Unimplemented: Read as '0'
bit 4 EEIP: Data EEPROM/FLASH Write Operation Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3 BCLIP: Bus Collision Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2 LVDIP: Low Voltage Detect Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 TMR3IP: TMR3 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0 CCP2IP: CCP2 Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 84 © 2006 Microchip Technology Inc.
8.5 RCON Register
The RCON register contains the bit which is used to
enable prioritized interrupts (IPEN).
REGISTER 8-10: RCON REGISTER
R/W-0 U-0 U-0 R/W-1 R-1 R-1 R/W-0 R/W-0
IPEN — — RI TO PD POR BOR
bit 7 bit 0
bit 7 IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (16CXXX Compatibility mode)
bit 6-5 Unimplemented: Read as '0'
bit 4 RI: RESET Instruction Flag bit
For details of bit operation, see Register 4-3
bit 3 TO: Watchdog Time-out Flag bit
For details of bit operation, see Register 4-3
bit 2 PD: Power-down Detection Flag bit
For details of bit operation, see Register 4-3
bit 1 POR: Power-on Reset Status bit
For details of bit operation, see Register 4-3
bit 0 BOR: Brown-out Reset Status bit
For details of bit operation, see Register 4-3
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 85
PIC18FXX2
8.6 INT0 Interrupt
External interrupts on the RB0/INT0, RB1/INT1 and
RB2/INT2 pins are edge triggered: either rising, if the
corresponding INTEDGx bit is set in the INTCON2 register,
or falling, if the INTEDGx bit is clear. When a valid
edge appears on the RBx/INTx pin, the corresponding
flag bit INTxF is set. This interrupt can be disabled by
clearing the corresponding enable bit INTxE. Flag bit
INTxF must be cleared in software in the Interrupt Service
Routine before re-enabling the interrupt. All external
interrupts (INT0, INT1 and INT2) can wake-up the
processor from SLEEP, if bit INTxE was set prior to
going into SLEEP. If the global interrupt enable bit GIE
is set, the processor will branch to the interrupt vector
following wake-up.
Interrupt priority for INT1 and INT2 is determined by the
value contained in the interrupt priority bits, INT1IP
(INTCON3<6>) and INT2IP (INTCON3<7>). There is
no priority bit associated with INT0. It is always a high
priority interrupt source.
8.7 TMR0 Interrupt
In 8-bit mode (which is the default), an overflow
(FFh → 00h) in the TMR0 register will set flag bit
TMR0IF. In 16-bit mode, an overflow (FFFFh → 0000h)
in the TMR0H:TMR0L registers will set flag bit TMR0IF.
The interrupt can be enabled/disabled by setting/
clearing enable bit T0IE (INTCON<5>). Interrupt priority
for Timer0 is determined by the value contained in
the interrupt priority bit TMR0IP (INTCON2<2>). See
Section 10.0 for further details on the Timer0 module.
8.8 PORTB Interrupt-on-Change
An input change on PORTB<7:4> sets flag bit RBIF
(INTCON<0>). The interrupt can be enabled/disabled
by setting/clearing enable bit, RBIE (INTCON<3>).
Interrupt priority for PORTB interrupt-on-change is
determined by the value contained in the interrupt
priority bit, RBIP (INTCON2<0>).
8.9 Context Saving During Interrupts
During an interrupt, the return PC value is saved on the
stack. Additionally, the WREG, STATUS and BSR registers
are saved on the fast return stack. If a fast return
from interrupt is not used (See Section 4.3), the user
may need to save the WREG, STATUS and BSR registers
in software. Depending on the user’s application,
other registers may also need to be saved. Equation 8-1
saves and restores the WREG, STATUS and BSR
registers during an Interrupt Service Routine.
EXAMPLE 8-1: SAVING STATUS, WREG AND BSR REGISTERS IN RAM
MOVWF W_TEMP ; W_TEMP is in virtual bank
MOVFF STATUS, STATUS_TEMP ; STATUS_TEMP located anywhere
MOVFF BSR, BSR_TEMP ; BSR located anywhere
;
; USER ISR CODE
;
MOVFF BSR_TEMP, BSR ; Restore BSR
MOVF W_TEMP, W ; Restore WREG
MOVFF STATUS_TEMP,STATUS ; Restore STATUSPIC18FXX2
DS39564C-page 86 © 2006 Microchip Technology Inc.
NOTES: © 2006 Microchip Technology Inc. DS39564C-page 87
PIC18FXX2
9.0 I/O PORTS
Depending on the device selected, there are either five
ports or three ports available. Some pins of the I/O
ports are multiplexed with an alternate function from
the peripheral features on the device. In general, when
a peripheral is enabled, that pin may not be used as a
general purpose I/O pin.
Each port has three registers for its operation. These
registers are:
• TRIS register (data direction register)
• PORT register (reads the levels on the pins of the
device)
• LAT register (output latch)
The data latch (LAT register) is useful for read-modifywrite
operations on the value that the I/O pins are
driving.
9.1 PORTA, TRISA and LATA
Registers
PORTA is a 7-bit wide, bi-directional port. The corresponding
Data Direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch.
The Data Latch register (LATA) is also memory
mapped. Read-modify-write operations on the LATA
register reads and writes the latched output value for
PORTA.
The RA4 pin is multiplexed with the Timer0 module
clock input to become the RA4/T0CKI pin. The RA4/
T0CKI pin is a Schmitt Trigger input and an open drain
output. All other RA port pins have TTL input levels and
full CMOS output drivers.
The other PORTA pins are multiplexed with analog
inputs and the analog VREF+ and VREF- inputs. The
operation of each pin is selected by clearing/setting the
control bits in the ADCON1 register (A/D Control
Register1).
The TRISA register controls the direction of the RA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
EXAMPLE 9-1: INITIALIZING PORTA
FIGURE 9-1: BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
Note: On a Power-on Reset, RA5 and RA3:RA0
are configured as analog inputs and read
as ‘0’. RA6 and RA4 are configured as
digital inputs.
CLRF PORTA ; Initialize PORTA by
; clearing output
; data latches
CLRF LATA ; Alternate method
; to clear output
; data latches
MOVLW 0x07 ; Configure A/D
MOVWF ADCON1 ; for digital inputs
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISA ; Set RA<3:0> as inputs
; RA<5:4> as outputs
Data
Bus
D Q
CK Q
D Q
CK Q
Q D
EN
P
N
WR LATA
WR TRISA
Data Latch
TRIS Latch
RD TRISA
RD PORTA
VSS
VDD
I/O pin(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
Analog
Input
Mode
TTL
Input
Buffer
To A/D Converter and LVD Modules
RD LATA
or
PORTA
SS Input (RA5 only)PIC18FXX2
DS39564C-page 88 © 2006 Microchip Technology Inc.
FIGURE 9-2: BLOCK DIAGRAM OF
RA4/T0CKI PIN
FIGURE 9-3: BLOCK DIAGRAM OF
RA6 PIN
Data
Bus
WR TRISA
RD PORTA
Data Latch
TRIS Latch
RD TRISA
Schmitt
Trigger
Input
Buffer
N
VSS
I/O pin(1)
TMR0 Clock Input
D Q
CK Q
D Q
CK Q
EN
Q D
EN
RD LATA
WR LATA
or
PORTA
Note 1: I/O pin has protection diode to VSS only.
Data
Bus
D Q
CK Q
Q D
EN
P
N
WR LATA
WR
Data Latch
TRIS Latch
RD TRISA
RD PORTA
VSS
VDD
I/O pin(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
or
PORTA
RD LATA
ECRA6 or
ECRA6 or
Enable
TTL
Input
Buffer
RCRA6
RCRA6 Enable
TRISA
D Q
CK Q© 2006 Microchip Technology Inc. DS39564C-page 89
PIC18FXX2
TABLE 9-1: PORTA FUNCTIONS
TABLE 9-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name Bit# Buffer Function
RA0/AN0 bit0 TTL Input/output or analog input.
RA1/AN1 bit1 TTL Input/output or analog input.
RA2/AN2/VREF- bit2 TTL Input/output or analog input or VREF-.
RA3/AN3/VREF+ bit3 TTL Input/output or analog input or VREF+.
RA4/T0CKI bit4 ST Input/output or external clock input for Timer0.
Output is open drain type.
RA5/SS/AN4/LVDIN bit5 TTL Input/output or slave select input for synchronous serial port or analog
input, or low voltage detect input.
OSC2/CLKO/RA6 bit6 TTL OSC2 or clock output or I/O pin.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
POR,
BOR
Value on
All Other
RESETS
PORTA — RA6 RA5 RA4 RA3 RA2 RA1 RA0 -x0x 0000 -u0u 0000
LATA — LATA Data Output Register -xxx xxxx -uuu uuuu
TRISA — PORTA Data Direction Register -111 1111 -111 1111
ADCON1 ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 00-- 0000
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.PIC18FXX2
DS39564C-page 90 © 2006 Microchip Technology Inc.
9.2 PORTB, TRISB and LATB
Registers
PORTB is an 8-bit wide, bi-directional port. The corresponding
Data Direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISB bit (= 0) will
make the corresponding PORTB pin an output (i.e., put
the contents of the output latch on the selected pin).
The Data Latch register (LATB) is also memory
mapped. Read-modify-write operations on the LATB
register reads and writes the latched output value for
PORTB.
EXAMPLE 9-2: INITIALIZING PORTB
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is performed
by clearing bit RBPU (INTCON2<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
Four of the PORTB pins, RB7:RB4, have an interrupton-change
feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupton-change
comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB Port Change
Interrupt with flag bit, RBIF (INTCON<0>).
This interrupt can wake the device from SLEEP. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a) Any read or write of PORTB (except with the
MOVFF instruction). This will end the mismatch
condition.
b) Clear flag bit RBIF.
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
RB3 can be configured by the configuration bit
CCP2MX as the alternate peripheral pin for the CCP2
module (CCP2MX=’0’).
FIGURE 9-4: BLOCK DIAGRAM OF
RB7:RB4 PINS
Note: On a Power-on Reset, these pins are
configured as digital inputs.
CLRF PORTB ; Initialize PORTB by
; clearing output
; data latches
CLRF LATB ; Alternate method
; to clear output
; data latches
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISB ; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs
Note 1: While in Low Voltage ICSP mode, the
RB5 pin can no longer be used as a general
purpose I/O pin, and should be held
low during normal operation to protect
against inadvertent ICSP mode entry.
2: When using Low Voltage ICSP programming
(LVP), the pull-up on RB5 becomes
disabled. If TRISB bit 5 is cleared,
thereby setting RB5 as an output, LATB
bit 5 must also be cleared for proper
operation.
Data Latch
From other
RBPU(2)
P
VDD
I/O pin(1)
D Q
CK
D Q
CK
Q D
EN
Q D
EN
Data Bus
WR LATB
WR TRISB
Set RBIF
TRIS Latch
RD TRISB
RD PORTB
RB7:RB4 pins
Weak
Pull-up
RD PORTB
Latch
TTL
Input
Buffer ST
Buffer
RB7:RB5 in Serial Programming mode
Q3
Q1
RD LATB
or
PORTB
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (INTCON2<7>).© 2006 Microchip Technology Inc. DS39564C-page 91
PIC18FXX2
FIGURE 9-5: BLOCK DIAGRAM OF RB2:RB0 PINS
FIGURE 9-6: BLOCK DIAGRAM OF RB3 PIN
Data Latch
RBPU(2)
P
VDD
D Q
CK
D Q
CK
Q D
EN
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
Weak
Pull-up
RD Port
RB0/INT
I/O pin(1)
TTL
Input
Buffer
Schmitt Trigger
Buffer
TRIS Latch
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (OPTION_REG<7>).
Data Latch
P
VDD
D Q
CK
Q D
EN
Data Bus
WR LATB or
WR TRISB
RD TRISB
RD PORTB
Weak
Pull-up
CCP2 Input(3)
TTL
Input
Buffer
Schmitt Trigger
Buffer
TRIS Latch
RD LATB
WR PORTB
RBPU(2)
CK
D
Enable(3)
CCP Output
RD PORTB
CCP Output(3) 1
0
P
N
VDD
VSS
I/O pin(1)
Q
CCP2MX
CCP2MX = 0
Note 1: I/O pin has diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate DDR bit(s) and clear the RBPU bit (INTCON2<7>).
3: The CCP2 input/output is multiplexed with RB3 if the CCP2MX bit is enabled (=’0’) in the configuration register. PIC18FXX2
DS39564C-page 92 © 2006 Microchip Technology Inc.
TABLE 9-3: PORTB FUNCTIONS
TABLE 9-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Name Bit# Buffer Function
RB0/INT0 bit0 TTL/ST(1) Input/output pin or external interrupt input0.
Internal software programmable weak pull-up.
RB1/INT1 bit1 TTL/ST(1) Input/output pin or external interrupt input1.
Internal software programmable weak pull-up.
RB2/INT2 bit2 TTL/ST(1) Input/output pin or external interrupt input2.
Internal software programmable weak pull-up.
RB3/CCP2(3) bit3 TTL/ST(4) Input/output pin or Capture2 input/Compare2 output/PWM output when
CCP2MX configuration bit is enabled.
Internal software programmable weak pull-up.
RB4 bit4 TTL Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
RB5/PGM(5) bit5 TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Low voltage ICSP enable pin.
RB6/PGC bit6 TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Serial programming clock.
RB7/PGD bit7 TTL/ST(2) Input/output pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3: A device configuration bit selects which I/O pin the CCP2 pin is multiplexed on.
4: This buffer is a Schmitt Trigger input when configured as the CCP2 input.
5: Low Voltage ICSP Programming (LVP) is enabled by default, which disables the RB5 I/O function. LVP
must be disabled to enable RB5 as an I/O pin and allow maximum compatibility to the other 28-pin and
40-pin mid-range devices.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
LATB LATB Data Output Register xxxx xxxx uuuu uuuu
TRISB PORTB Data Direction Register 1111 1111 1111 1111
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
INTCON2 RBPU INTEDG0 INTEDG1 INTEDG2 — TMR0IP — RBIP 1111 -1-1 1111 -1-1
INTCON3 INT2IP INT1IP — INT2IE INT1IE — INT2IF INT1IF 11-0 0-00 11-0 0-00
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.© 2006 Microchip Technology Inc. DS39564C-page 93
PIC18FXX2
9.3 PORTC, TRISC and LATC
Registers
PORTC is an 8-bit wide, bi-directional port. The corresponding
Data Direction register is TRISC. Setting a
TRISC bit (= 1) will make the corresponding PORTC
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISC bit (= 0) will
make the corresponding PORTC pin an output (i.e., put
the contents of the output latch on the selected pin).
The Data Latch register (LATC) is also memory
mapped. Read-modify-write operations on the LATC
register reads and writes the latched output value for
PORTC.
PORTC is multiplexed with several peripheral functions
(Table 9-5). PORTC pins have Schmitt Trigger input
buffers.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output,
while other peripherals override the TRIS bit to
make a pin an input. The user should refer to the corresponding
peripheral section for the correct TRIS bit
settings.
The pin override value is not loaded into the TRIS register.
This allows read-modify-write of the TRIS register,
without concern due to peripheral overrides.
RC1 is normally configured by configuration bit,
CCP2MX, as the default peripheral pin of the CCP2
module (default/erased state, CCP2MX = ’1’).
EXAMPLE 9-3: INITIALIZING PORTC
FIGURE 9-7: PORTC BLOCK DIAGRAM (PERIPHERAL OUTPUT OVERRIDE)
Note: On a Power-on Reset, these pins are
configured as digital inputs.
CLRF PORTC ; Initialize PORTC by
; clearing output
; data latches
CLRF LATC ; Alternate method
; to clear output
; data latches
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISC ; Set RC<3:0> as inputs
; RC<5:4> as outputs
; RC<7:6> as inputs
Data Bus
WR LATC or
WR TRISC
RD TRISC
D Q
CK Q
Q D
EN
Peripheral Data Out
0
1
D Q
CK Q
RD PORTC
Peripheral Data In
WR PORTC
RD LATC
Peripheral Output
Schmitt
Port/Peripheral Select(2)
Enable(3)
P
N
VSS
VDD
I/O pin(1)
Note 1: I/O pins have diode protection to VDD and VSS.
2: Port/Peripheral Select signal selects between port data (input) and peripheral output.
3: Peripheral Output Enable is only active if peripheral select is active.
Data Latch
TRIS Latch
TriggerPIC18FXX2
DS39564C-page 94 © 2006 Microchip Technology Inc.
TABLE 9-5: PORTC FUNCTIONS
TABLE 9-6: SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Name Bit# Buffer Type Function
RC0/T1OSO/T1CKI bit0 ST Input/output port pin or Timer1 oscillator output/Timer1 clock input.
RC1/T1OSI/CCP2 bit1 ST Input/output port pin, Timer1 oscillator input, or Capture2 input/
Compare2 output/PWM output when CCP2MX configuration bit is
set.
RC2/CCP1 bit2 ST Input/output port pin or Capture1 input/Compare1 output/PWM1
output.
RC3/SCK/SCL bit3 ST RC3 can also be the synchronous serial clock for both SPI and I2C
modes.
RC4/SDI/SDA bit4 ST RC4 can also be the SPI Data In (SPI mode) or Data I/O (I2C mode).
RC5/SDO bit5 ST Input/output port pin or Synchronous Serial Port data output.
RC6/TX/CK bit6 ST Input/output port pin, Addressable USART Asynchronous Transmit, or
Addressable USART Synchronous Clock.
RC7/RX/DT bit7 ST Input/output port pin, Addressable USART Asynchronous Receive, or
Addressable USART Synchronous Data.
Legend: ST = Schmitt Trigger input
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0 xxxx xxxx uuuu uuuu
LATC LATC Data Output Register xxxx xxxx uuuu uuuu
TRISC PORTC Data Direction Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged© 2006 Microchip Technology Inc. DS39564C-page 95
PIC18FXX2
9.4 PORTD, TRISD and LATD
Registers
This section is applicable only to the PIC18F4X2
devices.
PORTD is an 8-bit wide, bi-directional port. The corresponding
Data Direction register is TRISD. Setting a
TRISD bit (= 1) will make the corresponding PORTD
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISD bit (= 0) will
make the corresponding PORTD pin an output (i.e., put
the contents of the output latch on the selected pin).
The Data Latch register (LATD) is also memory
mapped. Read-modify-write operations on the LATD
register reads and writes the latched output value for
PORTD.
PORTD is an 8-bit port with Schmitt Trigger input buffers.
Each pin is individually configurable as an input or
output.
PORTD can be configured as an 8-bit wide microprocessor
port (parallel slave port) by setting control bit
PSPMODE (TRISE<4>). In this mode, the input buffers
are TTL. See Section 9.6 for additional information on
the Parallel Slave Port (PSP).
EXAMPLE 9-4: INITIALIZING PORTD
FIGURE 9-8: PORTD BLOCK DIAGRAM
IN I/O PORT MODE
Note: On a Power-on Reset, these pins are
configured as digital inputs.
CLRF PORTD ; Initialize PORTD by
; clearing output
; data latches
CLRF LATD ; Alternate method
; to clear output
; data latches
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISD ; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs
Data
Bus
WR LATD
WR TRISD
RD PORTD
Data Latch
TRIS Latch
RD TRISD
Schmitt
Trigger
Input
Buffer
I/O pin(1)
D Q
CK
D Q
CK
EN
Q D
EN
RD LATD
or
PORTD
Note 1: I/O pins have diode protection to VDD and VSS.PIC18FXX2
DS39564C-page 96 © 2006 Microchip Technology Inc.
TABLE 9-7: PORTD FUNCTIONS
TABLE 9-8: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Name Bit# Buffer Type Function
RD0/PSP0 bit0 ST/TTL(1) Input/output port pin or parallel slave port bit0.
RD1/PSP1 bit1 ST/TTL(1) Input/output port pin or parallel slave port bit1.
RD2/PSP2 bit2 ST/TTL(1) Input/output port pin or parallel slave port bit2.
RD3/PSP3 bit3 ST/TTL(1) Input/output port pin or parallel slave port bit3.
RD4/PSP4 bit4 ST/TTL(1) Input/output port pin or parallel slave port bit4.
RD5/PSP5 bit5 ST/TTL(1) Input/output port pin or parallel slave port bit5.
RD6/PSP6 bit6 ST/TTL(1) Input/output port pin or parallel slave port bit6.
RD7/PSP7 bit7 ST/TTL(1) Input/output port pin or parallel slave port bit7.
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffer when in Parallel Slave Port mode.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 xxxx xxxx uuuu uuuu
LATD LATD Data Output Register xxxx xxxx uuuu uuuu
TRISD PORTD Data Direction Register 1111 1111 1111 1111
TRISE IBF OBF IBOV PSPMODE — PORTE Data Direction bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PORTD.© 2006 Microchip Technology Inc. DS39564C-page 97
PIC18FXX2
9.5 PORTE, TRISE and LATE
Registers
This section is only applicable to the PIC18F4X2
devices.
PORTE is a 3-bit wide, bi-directional port. The corresponding
Data Direction register is TRISE. Setting a
TRISE bit (= 1) will make the corresponding PORTE pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISE bit (= 0) will
make the corresponding PORTE pin an output (i.e., put
the contents of the output latch on the selected pin).
The Data Latch register (LATE) is also memory
mapped. Read-modify-write operations on the LATE
register reads and writes the latched output value for
PORTE.
PORTE has three pins (RE0/RD/AN5, RE1/WR/AN6
and RE2/CS/AN7) which are individually configurable
as inputs or outputs. These pins have Schmitt Trigger
input buffers.
Register 9-1 shows the TRISE register, which also
controls the parallel slave port operation.
PORTE pins are multiplexed with analog inputs. When
selected as an analog input, these pins will read as '0's.
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
EXAMPLE 9-5: INITIALIZING PORTE
FIGURE 9-9: PORTE BLOCK DIAGRAM
IN I/O PORT MODE
Note: On a Power-on Reset, these pins are
configured as analog inputs.
CLRF PORTE ; Initialize PORTE by
; clearing output
; data latches
CLRF LATE ; Alternate method
; to clear output
; data latches
MOVLW 0x07 ; Configure A/D
MOVWF ADCON1 ; for digital inputs
MOVLW 0x05 ; Value used to
; initialize data
; direction
MOVWF TRISE ; Set RE<0> as inputs
; RE<1> as outputs
; RE<2> as inputs
Data
Bus
WR LATE
WR TRISE
RD PORTE
Data Latch
TRIS Latch
RD TRISE
Schmitt
Trigger
Input
Buffer
D Q
CK
D Q
CK
EN
Q D
EN
I/O pin(1)
RD LATE
or
PORTE
To Analog Converter
Note 1: I/O pins have diode protection to VDD and VSS.PIC18FXX2
DS39564C-page 98 © 2006 Microchip Technology Inc.
REGISTER 9-1: TRISE REGISTER
R-0 R-0 R/W-0 R/W-0 U-0 R/W-1 R/W-1 R/W-1
IBF OBF IBOV PSPMODE — TRISE2 TRISE1 TRISE0
bit 7 bit 0
bit 7 IBF: Input Buffer Full Status bit
1 = A word has been received and waiting to be read by the CPU
0 = No word has been received
bit 6 OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written word
0 = The output buffer has been read
bit 5 IBOV: Input Buffer Overflow Detect bit (in Microprocessor mode)
1 = A write occurred when a previously input word has not been read
(must be cleared in software)
0 = No overflow occurred
bit 4 PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel Slave Port mode
0 = General purpose I/O mode
bit 3 Unimplemented: Read as '0'
bit 2 TRISE2: RE2 Direction Control bit
1 = Input
0 = Output
bit 1 TRISE1: RE1 Direction Control bit
1 = Input
0 = Output
bit 0 TRISE0: RE0 Direction Control bit
1 = Input
0 = Output
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 99
PIC18FXX2
TABLE 9-9: PORTE FUNCTIONS
TABLE 9-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Name Bit# Buffer Type Function
RE0/RD/AN5 bit0 ST/TTL(1)
Input/output port pin or read control input in Parallel Slave Port mode
or analog input:
RD
1 = Not a read operation
0 = Read operation. Reads PORTD register (if chip selected).
RE1/WR/AN6 bit1 ST/TTL(1)
Input/output port pin or write control input in Parallel Slave Port mode
or analog input:
WR
1 = Not a write operation
0 = Write operation. Writes PORTD register (if chip selected).
RE2/CS/AN7 bit2 ST/TTL(1)
Input/output port pin or chip select control input in Parallel Slave Port
mode or analog input:
CS
1 = Device is not selected
0 = Device is selected
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
PORTE — — — — — RE2 RE1 RE0 ---- -000 ---- -000
LATE — — — — — LATE Data Output Register ---- -xxx ---- -uuu
TRISE IBF OBF IBOV PSPMODE — PORTE Data Direction bits 0000 -111 0000 -111
ADCON1 ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 00-- 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PORTE.PIC18FXX2
DS39564C-page 100 © 2006 Microchip Technology Inc.
9.6 Parallel Slave Port
The Parallel Slave Port is implemented on the 40-pin
devices only (PIC18F4X2).
PORTD operates as an 8-bit wide Parallel Slave Port,
or microprocessor port when control bit, PSPMODE
(TRISE<4>) is set. It is asynchronously readable and
writable by the external world through RD control input
pin, RE0/RD and WR control input pin, RE1/WR.
It can directly interface to an 8-bit microprocessor data
bus. The external microprocessor can read or write the
PORTD latch as an 8-bit latch. Setting bit PSPMODE
enables port pin RE0/RD to be the RD input, RE1/WR
to be the WR input and RE2/CS to be the CS (chip
select) input. For this functionality, the corresponding
data direction bits of the TRISE register (TRISE<2:0>)
must be configured as inputs (set). The A/D port configuration
bits PCFG2:PCFG0 (ADCON1<2:0>) must be
set, which will configure pins RE2:RE0 as digital I/O.
A write to the PSP occurs when both the CS and WR
lines are first detected low. A read from the PSP occurs
when both the CS and RD lines are first detected low.
The PORTE I/O pins become control inputs for the
microprocessor port when bit PSPMODE (TRISE<4>)
is set. In this mode, the user must make sure that the
TRISE<2:0> bits are set (pins are configured as digital
inputs), and the ADCON1 is configured for digital I/O.
In this mode, the input buffers are TTL.
FIGURE 9-10: PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE
PORT)
FIGURE 9-11: PARALLEL SLAVE PORT WRITE WAVEFORMS
Data Bus
WR LATD
RDx
D Q
CK
EN
Q D
RD PORTD EN
Pin
One bit of PORTD
Set Interrupt Flag
PSPIF (PIR1<7>)
Read
Chip Select
Write
RD
CS
WR
Note: I/O pin has protection diodes to VDD and VSS.
TTL
TTL
TTL
TTL
or
PORTD
RD LATD
Data Latch
TRIS Latch
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
RD
IBF
OBF
PSPIF
PORTD<7:0>© 2006 Microchip Technology Inc. DS39564C-page 101
PIC18FXX2
FIGURE 9-12: PARALLEL SLAVE PORT READ WAVEFORMS
TABLE 9-11: REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
IBF
PSPIF
RD
OBF
PORTD<7:0>
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
PORTD Port Data Latch when written; Port pins when read xxxx xxxx uuuu uuuu
LATD LATD Data Output bits xxxx xxxx uuuu uuuu
TRISD PORTD Data Direction bits 1111 1111 1111 1111
PORTE — — — — — RE2 RE1 RE0 ---- -000 ---- -000
LATE — — — — — LATE Data Output bits ---- -xxx ---- -uuu
TRISE IBF OBF IBOV PSPMODE — PORTE Data Direction bits 0000 -111 0000 -111
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IF INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
ADCON1 ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 00-- 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Parallel Slave Port.PIC18FXX2
DS39564C-page 102 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 103
PIC18FXX2
10.0 TIMER0 MODULE
The Timer0 module has the following features:
• Software selectable as an 8-bit or 16-bit timer/
counter
• Readable and writable
• Dedicated 8-bit software programmable prescaler
• Clock source selectable to be external or internal
• Interrupt-on-overflow from FFh to 00h in 8-bit
mode and FFFFh to 0000h in 16-bit mode
• Edge select for external clock
Figure 10-1 shows a simplified block diagram of the
Timer0 module in 8-bit mode and Figure 10-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
The T0CON register (Register 10-1) is a readable and
writable register that controls all the aspects of Timer0,
including the prescale selection.
REGISTER 10-1: T0CON: TIMER0 CONTROL REGISTER
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0
bit 7 bit 0
bit 7 TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
bit 6 T08BIT: Timer0 8-bit/16-bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
bit 5 T0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
bit 4 T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin
bit 3 PSA: Timer0 Prescaler Assignment bit
1 = TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler.
0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits
111 = 1:256 prescale value
110 = 1:128 prescale value
101 = 1:64 prescale value
100 = 1:32 prescale value
011 = 1:16 prescale value
010 = 1:8 prescale value
001 = 1:4 prescale value
000 = 1:2 prescale value
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 104 © 2006 Microchip Technology Inc.
FIGURE 10-1: TIMER0 BLOCK DIAGRAM IN 8-BIT MODE
FIGURE 10-2: TIMER0 BLOCK DIAGRAM IN 16-BIT MODE
Note: Upon RESET, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
RA4/T0CKI pin
T0SE
0
1
1
0
T0CS
FOSC/4
Programmable
Prescaler
Sync with
Internal
Clocks
TMR0L
(2 TCY delay)
Data Bus
8
PSA
T0PS2, T0PS1, T0PS0
Set Interrupt
Flag bit TMR0IF
on Overflow
3
Note: Upon RESET, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
T0CKI pin
T0SE
0
1
1
0
T0CS
FOSC/4
Programmable Prescaler
Sync with
Internal
Clocks TMR0L
(2 TCY delay)
Data Bus<7:0>
8
PSA
T0PS2, T0PS1, T0PS0
Set Interrupt
Flag bit TMR0IF
on Overflow
3
TMR0
TMR0H
High Byte
8
8
8
Read TMR0L
Write TMR0L© 2006 Microchip Technology Inc. DS39564C-page 105
PIC18FXX2
10.1 Timer0 Operation
Timer0 can operate as a timer or as a counter.
Timer mode is selected by clearing the T0CS bit. In
Timer mode, the Timer0 module will increment every
instruction cycle (without prescaler). If the TMR0L register
is written, the increment is inhibited for the following
two instruction cycles. The user can work around
this by writing an adjusted value to the TMR0L register.
Counter mode is selected by setting the T0CS bit. In
Counter mode, Timer0 will increment, either on every
rising or falling edge of pin RA4/T0CKI. The incrementing
edge is determined by the Timer0 Source Edge
Select bit (T0SE). Clearing the T0SE bit selects the rising
edge. Restrictions on the external clock input are
discussed below.
When an external clock input is used for Timer0, it must
meet certain requirements. The requirements ensure
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
10.2 Prescaler
An 8-bit counter is available as a prescaler for the Timer0
module. The prescaler is not readable or writable.
The PSA and T0PS2:T0PS0 bits determine the
prescaler assignment and prescale ratio.
Clearing bit PSA will assign the prescaler to the Timer0
module. When the prescaler is assigned to the Timer0
module, prescale values of 1:2, 1:4,..., 1:256 are
selectable.
When assigned to the Timer0 module, all instructions
writing to the TMR0L register (e.g., CLRF TMR0,
MOVWF TMR0, BSF TMR0, x....etc.) will clear the
prescaler count.
10.2.1 SWITCHING PRESCALER ASSIGNMENT
The prescaler assignment is fully under software control,
(i.e., it can be changed “on-the-fly” during program
execution).
10.3 Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0 register
overflows from FFh to 00h in 8-bit mode, or FFFFh
to 0000h in 16-bit mode. This overflow sets the TMR0IF
bit. The interrupt can be masked by clearing the
TMR0IE bit. The TMR0IE bit must be cleared in software
by the Timer0 module Interrupt Service Routine
before re-enabling this interrupt. The TMR0 interrupt
cannot awaken the processor from SLEEP, since the
timer is shut-off during SLEEP.
10.4 16-Bit Mode Timer Reads and
Writes
TMR0H is not the high byte of the timer/counter in
16-bit mode, but is actually a buffered version of the
high byte of Timer0 (refer to Figure 10-2). The high byte
of the Timer0 counter/timer is not directly readable nor
writable. TMR0H is updated with the contents of the
high byte of Timer0 during a read of TMR0L. This provides
the ability to read all 16-bits of Timer0 without
having to verify that the read of the high and low byte
were valid due to a rollover between successive reads
of the high and low byte.
A write to the high byte of Timer0 must also take place
through the TMR0H buffer register. Timer0 high byte is
updated with the contents of TMR0H when a write
occurs to TMR0L. This allows all 16-bits of Timer0 to be
updated at once.
TABLE 10-1: REGISTERS ASSOCIATED WITH TIMER0
Note: Writing to TMR0L when the prescaler is
assigned to Timer0 will clear the prescaler
count, but will not change the prescaler
assignment.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
TMR0L Timer0 Module Low Byte Register xxxx xxxx uuuu uuuu
TMR0H Timer0 Module High Byte Register 0000 0000 0000 0000
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
T0CON TMR0ON T08BIT T0CS T0SE PSA T0PS2 T0PS1 T0PS0 1111 1111 1111 1111
TRISA — PORTA Data Direction Register -111 1111 -111 1111
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by Timer0.PIC18FXX2
DS39564C-page 106 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 107
PIC18FXX2
11.0 TIMER1 MODULE
The Timer1 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR1H and TMR1L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt-on-overflow from FFFFh to 0000h
• RESET from CCP module special event trigger
Figure 11-1 is a simplified block diagram of the Timer1
module.
Register 11-1 details the Timer1 control register. This
register controls the Operating mode of the Timer1
module, and contains the Timer1 oscillator enable bit
(T1OSCEN). Timer1 can be enabled or disabled by
setting or clearing control bit TMR1ON (T1CON<0>).
REGISTER 11-1: T1CON: TIMER1 CONTROL REGISTER
R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
RD16 — T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON
bit 7 bit 0
bit 7 RD16: 16-bit Read/Write Mode Enable bit
1 = Enables register Read/Write of Timer1 in one 16-bit operation
0 = Enables register Read/Write of Timer1 in two 8-bit operations
bit 6 Unimplemented: Read as '0'
bit 5-4 T1CKPS1:T1CKPS0: Timer1 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 3 T1OSCEN: Timer1 Oscillator Enable bit
1 = Timer1 Oscillator is enabled
0 = Timer1 Oscillator is shut-off
The oscillator inverter and feedback resistor are turned off to eliminate power drain.
bit 2 T1SYNC: Timer1 External Clock Input Synchronization Select bit
When TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
bit 1 TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RC0/T1OSO/T13CKI (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0 TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 108 © 2006 Microchip Technology Inc.
11.1 Timer1 Operation
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
The Operating mode is determined by the clock select
bit, TMR1CS (T1CON<1>).
When TMR1CS = 0, Timer1 increments every instruction
cycle. When TMR1CS = 1, Timer1 increments on
every rising edge of the external clock input or the
Timer1 oscillator, if enabled.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T1CKI pins
become inputs. That is, the TRISC<1:0> value is
ignored, and the pins are read as ‘0’.
Timer1 also has an internal “RESET input”. This
RESET can be generated by the CCP module
(Section 14.0).
FIGURE 11-1: TIMER1 BLOCK DIAGRAM
FIGURE 11-2: TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
TMR1H TMR1L
T1SYNC
TMR1CS
T1CKPS1:T1CKPS0 SLEEP Input
FOSC/4
Internal
Clock
TMR1ON
On/Off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
Clock Input
2
TMR1IF
Overflow
TMR1
CLR
CCP Special Event Trigger
T1OSCEN
Enable
Oscillator(1)
T1OSC
Interrupt
Flag Bit
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
T1OSI
T1CKI/T1OSO
Timer 1
TMR1L
T1OSC
T1SYNC
TMR1CS
T1CKPS1:T1CKPS0
SLEEP Input
T1OSCEN
Enable
Oscillator(1)
TMR1IF
Overflow
Interrupt
FOSC/4
Internal
Clock
TMR1ON
on/off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
Clock Input
2
T13CKI/T1OSO
T1OSI
TMR1
Flag bit
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
High Byte
Data Bus<7:0>
8
TMR1H
8 8
8
Read TMR1L
Write TMR1L
CLR
CCP Special Event Trigger© 2006 Microchip Technology Inc. DS39564C-page 109
PIC18FXX2
11.2 Timer1 Oscillator
A crystal oscillator circuit is built-in between pins T1OSI
(input) and T1OSO (amplifier output). It is enabled by
setting control bit T1OSCEN (T1CON<3>). The oscillator
is a low power oscillator rated up to 200 kHz. It will
continue to run during SLEEP. It is primarily intended
for a 32 kHz crystal. Table 11-1 shows the capacitor
selection for the Timer1 oscillator.
The user must provide a software time delay to ensure
proper start-up of the Timer1 oscillator.
TABLE 11-1: CAPACITOR SELECTION FOR
THE ALTERNATE
OSCILLATOR
11.3 Timer1 Interrupt
The TMR1 Register pair (TMR1H:TMR1L) increments
from 0000h to FFFFh and rolls over to 0000h. The
TMR1 Interrupt, if enabled, is generated on overflow,
which is latched in interrupt flag bit TMR1IF (PIR1<0>).
This interrupt can be enabled/disabled by setting/
clearing TMR1 interrupt enable bit, TMR1IE (PIE1<0>).
11.4 Resetting Timer1 using a CCP
Trigger Output
If the CCP module is configured in Compare mode to
generate a “special event trigger” (CCP1M3:CCP1M0
= 1011), this signal will reset Timer1 and start an A/D
conversion (if the A/D module is enabled).
Timer1 must be configured for either Timer or Synchronized
Counter mode to take advantage of this feature.
If Timer1 is running in Asynchronous Counter mode,
this RESET operation may not work.
In the event that a write to Timer1 coincides with a
special event trigger from CCP1, the write will take
precedence.
In this mode of operation, the CCPR1H:CCPR1L registers
pair effectively becomes the period register for
Timer1.
11.5 Timer1 16-Bit Read/Write Mode
Timer1 can be configured for 16-bit reads and writes
(see Figure 11-2). When the RD16 control bit
(T1CON<7>) is set, the address for TMR1H is mapped
to a buffer register for the high byte of Timer1. A read
from TMR1L will load the contents of the high byte of
Timer1 into the Timer1 high byte buffer. This provides
the user with the ability to accurately read all 16-bits of
Timer1 without having to determine whether a read of
the high byte followed by a read of the low byte is valid,
due to a rollover between reads.
A write to the high byte of Timer1 must also take place
through the TMR1H buffer register. Timer1 high byte is
updated with the contents of TMR1H when a write
occurs to TMR1L. This allows a user to write all 16 bits
to both the high and low bytes of Timer1 at once.
The high byte of Timer1 is not directly readable or writable
in this mode. All reads and writes must take place
through the Timer1 high byte buffer register. Writes to
TMR1H do not clear the Timer1 prescaler. The
prescaler is only cleared on writes to TMR1L.
Osc Type Freq C1 C2
LP 32 kHz TBD(1) TBD(1)
Crystal to be Tested:
32.768 kHz Epson C-001R32.768K-A ± 20 PPM
Note 1: Microchip suggests 33 pF as a starting
point in validating the oscillator circuit.
2: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer
for appropriate values of external
components.
4: Capacitor values are for design guidance
only.
Note: The special event triggers from the CCP1
module will not set interrupt flag bit
TMR1IF (PIR1<0>). PIC18FXX2
DS39564C-page 110 © 2006 Microchip Technology Inc.
TABLE 11-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
T1CON RD16 — T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer1 module.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.© 2006 Microchip Technology Inc. DS39564C-page 111
PIC18FXX2
12.0 TIMER2 MODULE
The Timer2 module timer has the following features:
• 8-bit timer (TMR2 register)
• 8-bit period register (PR2)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4, 1:16)
• Software programmable postscaler (1:1 to 1:16)
• Interrupt on TMR2 match of PR2
• SSP module optional use of TMR2 output to
generate clock shift
Timer2 has a control register shown in Register 12-1.
Timer2 can be shut-off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption.
Figure 12-1 is a simplified block diagram of the Timer2
module. Register 12-1 shows the Timer2 control register.
The prescaler and postscaler selection of Timer2
are controlled by this register.
12.1 Timer2 Operation
Timer2 can be used as the PWM time-base for the
PWM mode of the CCP module. The TMR2 register is
readable and writable, and is cleared on any device
RESET. The input clock (FOSC/4) has a prescale option
of 1:1, 1:4 or 1:16, selected by control bits
T2CKPS1:T2CKPS0 (T2CON<1:0>). The match output
of TMR2 goes through a 4-bit postscaler (which
gives a 1:1 to 1:16 scaling inclusive) to generate a
TMR2 interrupt (latched in flag bit TMR2IF, (PIR1<1>)).
The prescaler and postscaler counters are cleared
when any of the following occurs:
• a write to the TMR2 register
• a write to the T2CON register
• any device RESET (Power-on Reset, MCLR
Reset, Watchdog Timer Reset, or Brown-out
Reset)
TMR2 is not cleared when T2CON is written.
REGISTER 12-1: T2CON: TIMER2 CONTROL REGISTER
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0
bit 7 bit 0
bit 7 Unimplemented: Read as '0'
bit 6-3 TOUTPS3:TOUTPS0: Timer2 Output Postscale Select bits
0000 = 1:1 Postscale
0001 = 1:2 Postscale
•
•
•
1111 = 1:16 Postscale
bit 2 TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0 T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 112 © 2006 Microchip Technology Inc.
12.2 Timer2 Interrupt
The Timer2 module has an 8-bit period register, PR2.
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is
initialized to FFh upon RESET.
12.3 Output of TMR2
The output of TMR2 (before the postscaler) is fed to the
Synchronous Serial Port module, which optionally uses
it to generate the shift clock.
FIGURE 12-1: TIMER2 BLOCK DIAGRAM
TABLE 12-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Comparator
TMR2 Sets Flag
TMR2
Output(1)
RESET
Postscaler
Prescaler
PR2
2
FOSC/4
1:1 to 1:16
1:1, 1:4, 1:16
EQ
4
bit TMR2IF
Note 1: TMR2 register output can be software selected by the SSP Module as a baud clock.
TOUTPS3:TOUTPS0
T2CKPS1:T2CKPS0
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
TMR2 Timer2 Module Register 0000 0000 0000 0000
T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
PR2 Timer2 Period Register 1111 1111 1111 1111
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the Timer2 module.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.© 2006 Microchip Technology Inc. DS39564C-page 113
PIC18FXX2
13.0 TIMER3 MODULE
The Timer3 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR3H and TMR3L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt-on-overflow from FFFFh to 0000h
• RESET from CCP module trigger
Figure 13-1 is a simplified block diagram of the Timer3
module.
Register 13-1 shows the Timer3 control register. This
register controls the Operating mode of the Timer3
module and sets the CCP clock source.
Register 11-1 shows the Timer1 control register. This
register controls the Operating mode of the Timer1
module, as well as contains the Timer1 oscillator
enable bit (T1OSCEN), which can be a clock source for
Timer3.
REGISTER 13-1: T3CON: TIMER3 CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON
bit 7 bit 0
bit 7 RD16: 16-bit Read/Write Mode Enable bit
1 = Enables register Read/Write of Timer3 in one 16-bit operation
0 = Enables register Read/Write of Timer3 in two 8-bit operations
bit 6-3 T3CCP2:T3CCP1: Timer3 and Timer1 to CCPx Enable bits
1x = Timer3 is the clock source for compare/capture CCP modules
01 = Timer3 is the clock source for compare/capture of CCP2,
Timer1 is the clock source for compare/capture of CCP1
00 = Timer1 is the clock source for compare/capture CCP modules
bit 5-4 T3CKPS1:T3CKPS0: Timer3 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 2 T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the system clock comes from Timer1/Timer3)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
bit 1 TMR3CS: Timer3 Clock Source Select bit
1 = External clock input from Timer1 oscillator or T1CKI
(on the rising edge after the first falling edge)
0 = Internal clock (FOSC/4)
bit 0 TMR3ON: Timer3 On bit
1 = Enables Timer3
0 = Stops Timer3
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 114 © 2006 Microchip Technology Inc.
13.1 Timer3 Operation
Timer3 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
The Operating mode is determined by the clock select
bit, TMR3CS (T3CON<1>).
When TMR3CS = 0, Timer3 increments every instruction
cycle. When TMR3CS = 1, Timer3 increments on
every rising edge of the Timer1 external clock input or
the Timer1 oscillator, if enabled.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T1CKI pins
become inputs. That is, the TRISC<1:0> value is
ignored, and the pins are read as ‘0’.
Timer3 also has an internal “RESET input”. This RESET
can be generated by the CCP module (Section 14.0).
FIGURE 13-1: TIMER3 BLOCK DIAGRAM
FIGURE 13-2: TIMER3 BLOCK DIAGRAM CONFIGURED IN 16-BIT READ/WRITE MODE
TMR3H TMR3L
T1OSC
T3SYNC
TMR3CS
T3CKPS1:T3CKPS0
SLEEP Input
T1OSCEN
Enable
Oscillator(1)
TMR3IF
Overflow
Interrupt
FOSC/4
Internal
Clock
TMR3ON
On/Off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
Clock Input
2
T1OSO/
T1OSI
Flag bit
(3)
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
T13CKI
CLR
CCP Special Trigger
T3CCPx
Timer3
TMR3L
T1OSC
T3SYNC
TMR3CS
T3CKPS1:T3CKPS0 SLEEP Input
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
TMR3ON
On/Off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
Clock Input
2
T1OSO/
T1OSI
TMR3
T13CKI
CLR
CCP Special Trigger
T3CCPx
To Timer1 Clock Input
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
High Byte
Data Bus<7:0>
8
TMR3H
8 8
8
Read TMR3L
Write TMR3L
Set TMR3IF Flag bit
on Overflow© 2006 Microchip Technology Inc. DS39564C-page 115
PIC18FXX2
13.2 Timer1 Oscillator
The Timer1 oscillator may be used as the clock source
for Timer3. The Timer1 oscillator is enabled by setting
the T1OSCEN (T1CON<3>) bit. The oscillator is a low
power oscillator rated up to 200 KHz. See Section 11.0
for further details.
13.3 Timer3 Interrupt
The TMR3 Register pair (TMR3H:TMR3L) increments
from 0000h to FFFFh and rolls over to 0000h. The
TMR3 Interrupt, if enabled, is generated on overflow,
which is latched in interrupt flag bit, TMR3IF
(PIR2<1>). This interrupt can be enabled/disabled by
setting/clearing TMR3 interrupt enable bit, TMR3IE
(PIE2<1>).
13.4 Resetting Timer3 Using a CCP
Trigger Output
If the CCP module is configured in Compare mode to
generate a “special event trigger” (CCP1M3:CCP1M0
= 1011), this signal will reset Timer3.
Timer3 must be configured for either Timer or Synchronized
Counter mode to take advantage of this feature.
If Timer3 is running in Asynchronous Counter mode,
this RESET operation may not work. In the event that a
write to Timer3 coincides with a special event trigger
from CCP1, the write will take precedence. In this mode
of operation, the CCPR1H:CCPR1L registers pair
effectively becomes the period register for Timer3.
TABLE 13-1: REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER
Note: The special event triggers from the CCP
module will not set interrupt flag bit,
TMR3IF (PIR1<0>).
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR2 — — — EEIF BCLIF LVDIF TMR3IF CCP2IF ---0 0000 ---0 0000
PIE2 — — — EEIE BCLIE LVDIE TMR3IE CCP2IE ---0 0000 ---0 0000
IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 ---1 1111
TMR3L Holding Register for the Least Significant Byte of the 16-bit TMR3 Register xxxx xxxx uuuu uuuu
TMR3H Holding Register for the Most Significant Byte of the 16-bit TMR3 Register xxxx xxxx uuuu uuuu
T1CON RD16 — T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 0000 0000 uuuu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the Timer1 module.PIC18FXX2
DS39564C-page 116 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 117
PIC18FXX2
14.0 CAPTURE/COMPARE/PWM
(CCP) MODULES
Each CCP (Capture/Compare/PWM) module contains
a 16-bit register which can operate as a 16-bit Capture
register, as a 16-bit Compare register or as a PWM
Master/Slave Duty Cycle register. Table 14-1 shows
the timer resources of the CCP Module modes.
The operation of CCP1 is identical to that of CCP2, with
the exception of the special event trigger. Therefore,
operation of a CCP module in the following sections is
described with respect to CCP1.
Table 14-2 shows the interaction of the CCP modules.
REGISTER 14-1: CCP1CON REGISTER/CCP2CON REGISTER
U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0
bit 7 bit 0
bit 7-6 Unimplemented: Read as '0'
bit 5-4 DCxB1:DCxB0: PWM Duty Cycle bit1 and bit0
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
These bits are the two LSbs (bit1 and bit0) of the 10-bit PWM duty cycle. The upper eight bits
(DCx9:DCx2) of the duty cycle are found in CCPRxL.
bit 3-0 CCPxM3:CCPxM0: CCPx Mode Select bits
0000 = Capture/Compare/PWM disabled (resets CCPx module)
0001 = Reserved
0010 = Compare mode, toggle output on match (CCPxIF bit is set)
0011 = Reserved
0100 = Capture mode, every falling edge
0101 = Capture mode, every rising edge
0110 = Capture mode, every 4th rising edge
0111 = Capture mode, every 16th rising edge
1000 = Compare mode,
Initialize CCP pin Low, on compare match force CCP pin High (CCPIF bit is set)
1001 = Compare mode,
Initialize CCP pin High, on compare match force CCP pin Low (CCPIF bit is set)
1010 = Compare mode,
Generate software interrupt on compare match (CCPIF bit is set, CCP pin is unaffected)
1011 = Compare mode,
Trigger special event (CCPIF bit is set)
11xx = PWM mode
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 118 © 2006 Microchip Technology Inc.
14.1 CCP1 Module
Capture/Compare/PWM Register 1 (CCPR1) is comprised
of two 8-bit registers: CCPR1L (low byte) and
CCPR1H (high byte). The CCP1CON register controls
the operation of CCP1. All are readable and writable.
TABLE 14-1: CCP MODE - TIMER
RESOURCE
14.2 CCP2 Module
Capture/Compare/PWM Register2 (CCPR2) is comprised
of two 8-bit registers: CCPR2L (low byte) and
CCPR2H (high byte). The CCP2CON register controls
the operation of CCP2. All are readable and writable.
TABLE 14-2: INTERACTION OF TWO CCP MODULES
CCP Mode Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2
CCPx Mode CCPy Mode Interaction
Capture Capture TMR1 or TMR3 time-base. Time-base can be different for each CCP.
Capture Compare The compare could be configured for the special event trigger,
which clears either TMR1 or TMR3 depending upon which time-base is used.
Compare Compare The compare(s) could be configured for the special event trigger,
which clears TMR1 or TMR3 depending upon which time-base is used.
PWM PWM The PWMs will have the same frequency and update rate
(TMR2 interrupt).
PWM Capture None
PWM Compare None© 2006 Microchip Technology Inc. DS39564C-page 119
PIC18FXX2
14.3 Capture Mode
In Capture mode, CCPR1H:CCPR1L captures the
16-bit value of the TMR1 or TMR3 registers when an
event occurs on pin RC2/CCP1. An event is defined as
one of the following:
• every falling edge
• every rising edge
• every 4th rising edge
• every 16th rising edge
The event is selected by control bits CCP1M3:CCP1M0
(CCP1CON<3:0>). When a capture is made, the interrupt
request flag bit CCP1IF (PIR1<2>) is set; it must be
cleared in software. If another capture occurs before the
value in register CCPR1 is read, the old captured value
is overwritten by the new captured value.
14.3.1 CCP PIN CONFIGURATION
In Capture mode, the RC2/CCP1 pin should be
configured as an input by setting the TRISC<2> bit.
14.3.2 TIMER1/TIMER3 MODE SELECTION
The timers that are to be used with the capture feature
(either Timer1 and/or Timer3) must be running in Timer
mode or Synchronized Counter mode. In Asynchronous
Counter mode, the capture operation may not
work. The timer to be used with each CCP module is
selected in the T3CON register.
14.3.3 SOFTWARE INTERRUPT
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep bit
CCP1IE (PIE1<2>) clear to avoid false interrupts and
should clear the flag bit, CCP1IF, following any such
change in Operating mode.
14.3.4 CCP PRESCALER
There are four prescaler settings, specified by bits
CCP1M3:CCP1M0. Whenever the CCP module is
turned off or the CCP module is not in Capture mode,
the prescaler counter is cleared. This means that any
RESET will clear the prescaler counter.
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared, therefore, the first capture may be from
a non-zero prescaler. Example 14-1 shows the recommended
method for switching between capture prescalers.
This example also clears the prescaler counter
and will not generate the “false” interrupt.
EXAMPLE 14-1: CHANGING BETWEEN
CAPTURE PRESCALERS
FIGURE 14-1: CAPTURE MODE OPERATION BLOCK DIAGRAM
Note: If the RC2/CCP1 is configured as an output,
a write to the port can cause a capture
condition.
CLRF CCP1CON, F ; Turn CCP module off
MOVLW NEW_CAPT_PS ; Load WREG with the
; new prescaler mode
; value and CCP ON
MOVWF CCP1CON ; Load CCP1CON with
; this value
CCPR1H CCPR1L
TMR1H TMR1L
Set Flag bit CCP1IF
TMR3
Enable
Q’s
CCP1CON<3:0>
CCP1 pin
Prescaler
÷ 1, 4, 16
and
Edge Detect
TMR3H TMR3L
TMR1
Enable
T3CCP2
T3CCP2
CCPR2H CCPR2L
TMR1H TMR1L
Set Flag bit CCP2IF
TMR3
Enable
Q’s
CCP2CON<3:0>
CCP2 pin
Prescaler
÷ 1, 4, 16
and
Edge Detect
TMR3H TMR3L
TMR1
Enable
T3CCP2
T3CCP1
T3CCP2
T3CCP1PIC18FXX2
DS39564C-page 120 © 2006 Microchip Technology Inc.
14.4 Compare Mode
In Compare mode, the 16-bit CCPR1 (CCPR2) register
value is constantly compared against either the TMR1
register pair value, or the TMR3 register pair value.
When a match occurs, the RC2/CCP1 (RC1/CCP2) pin
is:
• driven High
• driven Low
• toggle output (High to Low or Low to High)
• remains unchanged
The action on the pin is based on the value of control
bits CCP1M3:CCP1M0 (CCP2M3:CCP2M0). At the
same time, interrupt flag bit CCP1IF (CCP2IF) is set.
14.4.1 CCP PIN CONFIGURATION
The user must configure the CCPx pin as an output by
clearing the appropriate TRISC bit.
14.4.2 TIMER1/TIMER3 MODE SELECTION
Timer1 and/or Timer3 must be running in Timer mode
or Synchronized Counter mode if the CCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation may not work.
14.4.3 SOFTWARE INTERRUPT MODE
When generate software interrupt is chosen, the CCP1
pin is not affected. Only a CCP interrupt is generated (if
enabled).
14.4.4 SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated,
which may be used to initiate an action.
The special event trigger output of CCP1 resets the
TMR1 register pair. This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Timer1.
The special trigger output of CCPx resets either the
TMR1 or TMR3 register pair. Additionally, the CCP2
Special Event Trigger will start an A/D conversion if the
A/D module is enabled.
FIGURE 14-2: COMPARE MODE OPERATION BLOCK DIAGRAM
Note: Clearing the CCP1CON register will force
the RC2/CCP1 compare output latch to the
default low level. This is not the PORTC
I/O data latch.
Note: The special event trigger from the CCP2
module will not set the Timer1 or Timer3
interrupt flag bits.
CCPR1H CCPR1L
TMR1H TMR1L
Comparator
Q S
R
Output
Logic
Special Event Trigger
Set Flag bit CCP1IF
RC2/CCP1 pin Match
TRISC<2>
CCP1CON<3:0>
Mode Select
Output Enable
Special Event Trigger will:
Reset Timer1 or Timer3, but not set Timer1 or Timer3 interrupt flag bit,
and set bit GO/DONE (ADCON0<2>)
which starts an A/D conversion (CCP2 only)
TMR3H TMR3L
T3CCP2
CCPR2H CCPR2L
Comparator
0 1
T3CCP2
T3CCP1
Q S
R
Output
Logic
Special Event Trigger
Set Flag bit CCP2IF
RC1/CCP2 pin Match
TRISC<1>
CCP2CON<3:0>
Mode Select
Output Enable
0 1© 2006 Microchip Technology Inc. DS39564C-page 121
PIC18FXX2
TABLE 14-3: REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
TRISC PORTC Data Direction Register 1111 1111 1111 1111
TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
T1CON RD16 — T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0-00 0000 u-uu uuuu
CCPR1L Capture/Compare/PWM Register1 (LSB) xxxx xxxx uuuu uuuu
CCPR1H Capture/Compare/PWM Register1 (MSB) xxxx xxxx uuuu uuuu
CCP1CON — — DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
CCPR2L Capture/Compare/PWM Register2 (LSB) xxxx xxxx uuuu uuuu
CCPR2H Capture/Compare/PWM Register2 (MSB) xxxx xxxx uuuu uuuu
CCP2CON — — DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
PIR2 — — — EEIE BCLIF LVDIF TMR3IF CCP2IF ---0 0000 ---0 0000
PIE2 — — — EEIF BCLIE LVDIE TMR3IE CCP2IE ---0 0000 ---0 0000
IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 ---1 1111
TMR3L Holding Register for the Least Significant Byte of the 16-bit TMR3 Register xxxx xxxx uuuu uuuu
TMR3H Holding Register for the Most Significant Byte of the 16-bit TMR3 Register xxxx xxxx uuuu uuuu
T3CON RD16 T3CCP2 T3CKPS1 T3CKPS0 T3CCP1 T3SYNC TMR3CS TMR3ON 0000 0000 uuuu uuuu
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by Capture and Timer1.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2x2 devices; always maintain these bits clear.PIC18FXX2
DS39564C-page 122 © 2006 Microchip Technology Inc.
14.5 PWM Mode
In Pulse Width Modulation (PWM) mode, the CCP1 pin
produces up to a 10-bit resolution PWM output. Since
the CCP1 pin is multiplexed with the PORTC data latch,
the TRISC<2> bit must be cleared to make the CCP1
pin an output.
Figure 14-3 shows a simplified block diagram of the
CCP module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 14.5.3.
FIGURE 14-3: SIMPLIFIED PWM BLOCK
DIAGRAM
A PWM output (Figure 14-4) has a time-base (period)
and a time that the output stays high (duty cycle). The
frequency of the PWM is the inverse of the period
(1/period).
FIGURE 14-4: PWM OUTPUT
14.5.1 PWM PERIOD
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
PWM period = (PR2) + 1] • 4 • TOSC •
(TMR2 prescale value)
PWM frequency is defined as 1 / [PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCP1 pin is set (exception: if PWM duty
cycle = 0%, the CCP1 pin will not be set)
• The PWM duty cycle is latched from CCPR1L into
CCPR1H
14.5.2 PWM DUTY CYCLE
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON<5:4> bits. Up
to 10-bit resolution is available. The CCPR1L contains
the eight MSbs and the CCP1CON<5:4> contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON<5:4>. The following equation is
used to calculate the PWM duty cycle in time:
PWM duty cycle = (CCPR1L:CCP1CON<5:4>) •
TOSC • (TMR2 prescale value)
CCPR1L and CCP1CON<5:4> can be written to at any
time, but the duty cycle value is not latched into
CCPR1H until after a match between PR2 and TMR2
occurs (i.e., the period is complete). In PWM mode,
CCPR1H is a read only register.
The CCPR1H register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
When the CCPR1H and 2-bit latch match TMR2 concatenated
with an internal 2-bit Q clock or 2 bits of the
TMR2 prescaler, the CCP1 pin is cleared.
The maximum PWM resolution (bits) for a given PWM
frequency is given by the equation:
Note: Clearing the CCP1CON register will force
the CCP1 PWM output latch to the default
low level. This is not the PORTC I/O data
latch.
CCPR1L
CCPR1H (Slave)
Comparator
TMR2
Comparator
PR2
(Note 1)
R Q
S
Duty Cycle Registers CCP1CON<5:4>
Clear Timer,
CCP1 pin and
latch D.C.
TRISC<2>
RC2/CCP1
Note: 8-bit timer is concatenated with 2-bit internal Q clock or 2
bits of the prescaler to create 10-bit time-base.
Period
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
TMR2 = PR2
Note: The Timer2 postscaler (see Section 12.0)
is not used in the determination of the
PWM frequency. The postscaler could be
used to have a servo update rate at a
different frequency than the PWM output.
Note: If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
FOSC
FPWM
--------------- ⎝ ⎠ ⎛ ⎞ log
log( ) 2 PWM Resolution (max) = -----------------------------bits© 2006 Microchip Technology Inc. DS39564C-page 123
PIC18FXX2
14.5.3 SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP module for PWM operation:
1. Set the PWM period by writing to the PR2 register.
2. Set the PWM duty cycle by writing to the
CCPR1L register and CCP1CON<5:4> bits.
3. Make the CCP1 pin an output by clearing the
TRISC<2> bit.
4. Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
5. Configure the CCP1 module for PWM operation.
TABLE 14-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
TABLE 14-5: REGISTERS ASSOCIATED WITH PWM AND TIMER2
PWM Frequency 2.44 kHz 9.77 kHz 39.06 kHz 156.25 kHz 312.50 kHz 416.67 kHz
Timer Prescaler (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 14 12 10 8 7 6.58
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
TRISC PORTC Data Direction Register 1111 1111 1111 1111
TMR2 Timer2 Module Register 0000 0000 0000 0000
PR2 Timer2 Module Period Register 1111 1111 1111 1111
T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
CCPR1L Capture/Compare/PWM Register1 (LSB) xxxx xxxx uuuu uuuu
CCPR1H Capture/Compare/PWM Register1 (MSB) xxxx xxxx uuuu uuuu
CCP1CON — — DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
CCPR2L Capture/Compare/PWM Register2 (LSB) xxxx xxxx uuuu uuuu
CCPR2H Capture/Compare/PWM Register2 (MSB) xxxx xxxx uuuu uuuu
CCP2CON — — DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 --00 0000 --00 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by PWM and Timer2.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.PIC18FXX2
DS39564C-page 124 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 125
PIC18FXX2
15.0 MASTER SYNCHRONOUS
SERIAL PORT (MSSP)
MODULE
15.1 Master SSP (MSSP) Module
Overview
The Master Synchronous Serial Port (MSSP) module is
a serial interface useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers, display
drivers, A/D converters, etc. The MSSP module
can operate in one of two modes:
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I2C)
- Full Master mode
- Slave mode (with general address call)
The I2C interface supports the following modes in
hardware:
• Master mode
• Multi-Master mode
• Slave mode
15.2 Control Registers
The MSSP module has three associated registers.
These include a status register (SSPSTAT) and two
control registers (SSPCON1 and SSPCON2). The use
of these registers and their individual configuration bits
differ significantly, depending on whether the MSSP
module is operated in SPI or I2C mode.
Additional details are provided under the individual
sections.
15.3 SPI Mode
The SPI mode allows 8-bits of data to be synchronously
transmitted and received, simultaneously. All four modes
of SPI are supported. To accomplish communication,
typically three pins are used:
• Serial Data Out (SDO) - RC5/SDO
• Serial Data In (SDI) - RC4/SDI/SDA
• Serial Clock (SCK) - RC3/SCK/SCL/LVDIN
Additionally, a fourth pin may be used when in a Slave
mode of operation:
• Slave Select (SS) - RA5/SS/AN4
Figure 15-1 shows the block diagram of the MSSP
module when operating in SPI mode.
FIGURE 15-1: MSSP BLOCK DIAGRAM
(SPI MODE)
Read Write
Internal
Data Bus
SSPSR reg
SSPM3:SSPM0
bit0 shift
clock
SS Control
Enable
Edge
Select
Clock Select
TMR2 output
Prescaler TOSC
4, 16, 64
2
Edge
Select
2
4
Data to TX/RX in SSPSR
TRIS bit
2
SMP:CKE
RC5/SDO
( )
SSPBUF reg
RC4/SDI/SDA
RA5/SS/AN4
RC3/SCK/
SCL/LVDINPIC18FXX2
DS39564C-page 126 © 2006 Microchip Technology Inc.
15.3.1 REGISTERS
The MSSP module has four registers for SPI mode
operation. These are:
• MSSP Control Register1 (SSPCON1)
• MSSP Status Register (SSPSTAT)
• Serial Receive/Transmit Buffer (SSPBUF)
• MSSP Shift Register (SSPSR) - Not directly
accessible
SSPCON1 and SSPSTAT are the control and status
registers in SPI mode operation. The SSPCON1 register
is readable and writable. The lower 6 bits of the
SSPSTAT are read only. The upper two bits of the
SSPSTAT are read/write.
SSPSR is the shift register used for shifting data in or
out. SSPBUF is the buffer register to which data bytes
are written to or read from.
In receive operations, SSPSR and SSPBUF together
create a double buffered receiver. When SSPSR
receives a complete byte, it is transferred to SSPBUF
and the SSPIF interrupt is set.
During transmission, the SSPBUF is not double buffered.
A write to SSPBUF will write to both SSPBUF and
SSPSR.
REGISTER 15-1: SSPSTAT: MSSP STATUS REGISTER (SPI MODE)
R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0
SMP CKE D/A P S R/W UA BF
bit 7 bit 0
bit 7 SMP: Sample bit
SPI Master mode:
1 = Input data sampled at end of data output time
0 = Input data sampled at middle of data output time
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode
bit 6 CKE: SPI Clock Edge Select
When CKP = 0:
1 = Data transmitted on rising edge of SCK
0 = Data transmitted on falling edge of SCK
When CKP = 1:
1 = Data transmitted on falling edge of SCK
0 = Data transmitted on rising edge of SCK
bit 5 D/A: Data/Address bit
Used in I2C mode only
bit 4 P: STOP bit
Used in I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is
cleared.
bit 3 S: START bit
Used in I2C mode only
bit 2 R/W: Read/Write bit information
Used in I2C mode only
bit 1 UA: Update Address
Used in I2C mode only
bit 0 BF: Buffer Full Status bit (Receive mode only)
1 = Receive complete, SSPBUF is full
0 = Receive not complete, SSPBUF is empty
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 127
PIC18FXX2
REGISTER 15-2: SSPCON1: MSSP CONTROL REGISTER1 (SPI MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
bit 7 bit 0
bit 7 WCOL: Write Collision Detect bit (Transmit mode only)
1 = The SSPBUF register is written while it is still transmitting the previous word
(must be cleared in software)
0 = No collision
bit 6 SSPOV: Receive Overflow Indicator bit
SPI Slave mode:
1 = A new byte is received while the SSPBUF register is still holding the previous data. In case
of overflow, the data in SSPSR is lost. Overflow can only occur in Slave mode.The user
must read the SSPBUF, even if only transmitting data, to avoid setting overflow
(must be cleared in software).
0 = No overflow
Note: In Master mode, the overflow bit is not set since each new reception (and
transmission) is initiated by writing to the SSPBUF register.
bit 5 SSPEN: Synchronous Serial Port Enable bit
1 = Enables serial port and configures SCK, SDO, SDI, and SS as serial port pins
0 = Disables serial port and configures these pins as I/O port pins
Note: When enabled, these pins must be properly configured as input or output.
bit 4 CKP: Clock Polarity Select bit
1 = IDLE state for clock is a high level
0 = IDLE state for clock is a low level
bit 3-0 SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
0101 = SPI Slave mode, clock = SCK pin, SS pin control disabled, SS can be used as I/O pin
0100 = SPI Slave mode, clock = SCK pin, SS pin control enabled
0011 = SPI Master mode, clock = TMR2 output/2
0010 = SPI Master mode, clock = FOSC/64
0001 = SPI Master mode, clock = FOSC/16
0000 = SPI Master mode, clock = FOSC/4
Note: Bit combinations not specifically listed here are either reserved, or implemented in
I
2C mode only.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 128 © 2006 Microchip Technology Inc.
15.3.2 OPERATION
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPCON1<5:0>) and SSPSTAT<7:6>.
These control bits allow the following to be specified:
• Master mode (SCK is the clock output)
• Slave mode (SCK is the clock input)
• Clock Polarity (IDLE state of SCK)
• Data input sample phase (middle or end of data
output time)
• Clock edge (output data on rising/falling edge of
SCK)
• Clock Rate (Master mode only)
• Slave Select mode (Slave mode only)
The MSSP consists of a transmit/receive Shift Register
(SSPSR) and a buffer register (SSPBUF). The SSPSR
shifts the data in and out of the device, MSb first. The
SSPBUF holds the data that was written to the SSPSR,
until the received data is ready. Once the 8 bits of data
have been received, that byte is moved to the SSPBUF
register. Then the buffer full detect bit, BF
(SSPSTAT<0>), and the interrupt flag bit, SSPIF, are
set. This double buffering of the received data
(SSPBUF) allows the next byte to start reception before
reading the data that was just received. Any write to the
SSPBUF register during transmission/reception of data
will be ignored, and the write collision detect bit, WCOL
(SSPCON1<7>), will be set. User software must clear
the WCOL bit so that it can be determined if the following
write(s) to the SSPBUF register completed
successfully.
When the application software is expecting to receive
valid data, the SSPBUF should be read before the next
byte of data to transfer is written to the SSPBUF. Buffer
full bit, BF (SSPSTAT<0>), indicates when SSPBUF
has been loaded with the received data (transmission
is complete). When the SSPBUF is read, the BF bit is
cleared. This data may be irrelevant if the SPI is only a
transmitter. Generally, the MSSP Interrupt is used to
determine when the transmission/reception has completed.
The SSPBUF must be read and/or written. If the
interrupt method is not going to be used, then software
polling can be done to ensure that a write collision does
not occur. Example 15-1 shows the loading of the
SSPBUF (SSPSR) for data transmission.
The SSPSR is not directly readable or writable, and
can only be accessed by addressing the SSPBUF register.
Additionally, the MSSP status register (SSPSTAT)
indicates the various status conditions.
EXAMPLE 15-1: LOADING THE SSPBUF (SSPSR) REGISTER
LOOP BTFSS SSPSTAT, BF ;Has data been received(transmit complete)?
BRA LOOP ;No
MOVF SSPBUF, W ;WREG reg = contents of SSPBUF
MOVWF RXDATA ;Save in user RAM, if data is meaningful
MOVF TXDATA, W ;W reg = contents of TXDATA
MOVWF SSPBUF ;New data to xmit © 2006 Microchip Technology Inc. DS39564C-page 129
PIC18FXX2
15.3.3 ENABLING SPI I/O
To enable the serial port, SSP Enable bit, SSPEN
(SSPCON1<5>), must be set. To reset or reconfigure
SPI mode, clear the SSPEN bit, re-initialize the
SSPCON registers, and then set the SSPEN bit. This
configures the SDI, SDO, SCK, and SS pins as serial
port pins. For the pins to behave as the serial port function,
some must have their data direction bits (in the
TRIS register) appropriately programmed. That is:
• SDI is automatically controlled by the SPI module
• SDO must have TRISC<5> bit cleared
• SCK (Master mode) must have TRISC<3> bit
cleared
• SCK (Slave mode) must have TRISC<3> bit set
• SS must have TRISC<4> bit set
Any serial port function that is not desired may be
overridden by programming the corresponding data
direction (TRIS) register to the opposite value.
15.3.4 TYPICAL CONNECTION
Figure 15-2 shows a typical connection between two
microcontrollers. The master controller (Processor 1)
initiates the data transfer by sending the SCK signal.
Data is shifted out of both shift registers on their programmed
clock edge, and latched on the opposite
edge of the clock. Both processors should be programmed
to the same Clock Polarity (CKP), then both
controllers would send and receive data at the same
time. Whether the data is meaningful (or dummy data)
depends on the application software. This leads to
three scenarios for data transmission:
• Master sends data — Slave sends dummy data
• Master sends data — Slave sends data
• Master sends dummy data — Slave sends data
FIGURE 15-2: SPI MASTER/SLAVE CONNECTION
Serial Input Buffer
(SSPBUF)
Shift Register
(SSPSR)
MSb LSb
SDO
SDI
PROCESSOR 1
SCK
SPI Master SSPM3:SSPM0 = 00xxb
Serial Input Buffer
(SSPBUF)
Shift Register
(SSPSR)
MSb LSb
SDI
SDO
PROCESSOR 2
SCK
SPI Slave SSPM3:SSPM0 = 010xb
Serial ClockPIC18FXX2
DS39564C-page 130 © 2006 Microchip Technology Inc.
15.3.5 MASTER MODE
The master can initiate the data transfer at any time
because it controls the SCK. The master determines
when the slave (Processor 2, Figure 15-2) is to
broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSPBUF register is written to. If the SPI is
only going to receive, the SDO output could be disabled
(programmed as an input). The SSPSR register
will continue to shift in the signal present on the SDI pin
at the programmed clock rate. As each byte is
received, it will be loaded into the SSPBUF register as
if a normal received byte (interrupts and status bits
appropriately set). This could be useful in receiver
applications as a “Line Activity Monitor” mode.
The clock polarity is selected by appropriately programming
the CKP bit (SSPCON1<4>). This then, would
give waveforms for SPI communication as shown in
Figure 15-3, Figure 15-5, and Figure 15-6, where the
MSB is transmitted first. In Master mode, the SPI clock
rate (bit rate) is user programmable to be one of the
following:
• FOSC/4 (or TCY)
• FOSC/16 (or 4 • TCY)
• FOSC/64 (or 16 • TCY)
• Timer2 output/2
This allows a maximum data rate (at 40 MHz) of
10.00 Mbps.
Figure 15-3 shows the waveforms for Master mode.
When the CKE bit is set, the SDO data is valid before
there is a clock edge on SCK. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSPBUF is loaded with the received
data is shown.
FIGURE 15-3: SPI MODE WAVEFORM (MASTER MODE)
SCK
(CKP = 0
SCK
(CKP = 1
SCK
(CKP = 0
SCK
(CKP = 1
4 Clock
Modes
Input
Sample
Input
Sample
SDI
bit7 bit0
SDO bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
bit7 bit0
SDI
SSPIF
(SMP = 1)
(SMP = 0)
(SMP = 1)
CKE = 1)
CKE = 0)
CKE = 1)
CKE = 0)
(SMP = 0)
Write to
SSPBUF
SSPSR to
SSPBUF
SDO bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
(CKE = 0)
(CKE = 1)
Next Q4 cycle
after Q2↓© 2006 Microchip Technology Inc. DS39564C-page 131
PIC18FXX2
15.3.6 SLAVE MODE
In Slave mode, the data is transmitted and received as
the external clock pulses appear on SCK. When the
last bit is latched, the SSPIF interrupt flag bit is set.
While in Slave mode, the external clock is supplied by
the external clock source on the SCK pin. This external
clock must meet the minimum high and low times as
specified in the electrical specifications.
While in SLEEP mode, the slave can transmit/receive
data. When a byte is received, the device will wake-up
from sleep.
15.3.7 SLAVE SELECT
SYNCHRONIZATION
The SS pin allows a Synchronous Slave mode. The
SPI must be in Slave mode with SS pin control enabled
(SSPCON1<3:0> = 04h). The pin must not be driven
low for the SS pin to function as an input. The Data
Latch must be high. When the SS pin is low, transmission
and reception are enabled and the SDO pin is
driven. When the SS pin goes high, the SDO pin is no
longer driven, even if in the middle of a transmitted
byte, and becomes a floating output. External pull-up/
pull-down resistors may be desirable, depending on the
application.
When the SPI module resets, the bit counter is forced
to 0. This can be done by either forcing the SS pin to a
high level or clearing the SSPEN bit.
To emulate two-wire communication, the SDO pin can
be connected to the SDI pin. When the SPI needs to
operate as a receiver the SDO pin can be configured as
an input. This disables transmissions from the SDO.
The SDI can always be left as an input (SDI function),
since it cannot create a bus conflict.
FIGURE 15-4: SLAVE SYNCHRONIZATION WAVEFORM
Note 1: When the SPI is in Slave mode with SS
pin control enabled (SSPCON<3:0> =
0100), the SPI module will reset if the SS
pin is set to VDD.
2: If the SPI is used in Slave mode with CKE
set, then the SS pin control must be
enabled.
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit7
SDO bit7 bit6 bit7
SSPIF
Interrupt
(SMP = 0)
CKE = 0)
CKE = 0)
(SMP = 0)
Write to
SSPBUF
SSPSR to
SSPBUF
SS
Flag
bit0
bit7
bit0
Next Q4 cycle
after Q2↓PIC18FXX2
DS39564C-page 132 © 2006 Microchip Technology Inc.
FIGURE 15-5: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
FIGURE 15-6: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit7 bit0
SDO bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SSPIF
Interrupt
(SMP = 0)
CKE = 0)
CKE = 0)
(SMP = 0)
Write to
SSPBUF
SSPSR to
SSPBUF
SS
Flag
Optional
Next Q4 cycle
after Q2↓
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit7 bit0
SDO bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
SSPIF
Interrupt
(SMP = 0)
CKE = 1)
CKE = 1)
(SMP = 0)
Write to
SSPBUF
SSPSR to
SSPBUF
SS
Flag
Not Optional
Next Q4 cycle
after Q2↓© 2006 Microchip Technology Inc. DS39564C-page 133
PIC18FXX2
15.3.8 SLEEP OPERATION
In Master mode, all module clocks are halted and the
transmission/reception will remain in that state until the
device wakes from SLEEP. After the device returns to
Normal mode, the module will continue to transmit/
receive data.
In Slave mode, the SPI transmit/receive shift register
operates asynchronously to the device. This allows the
device to be placed in SLEEP mode and data to be
shifted into the SPI transmit/receive shift register.
When all 8 bits have been received, the MSSP interrupt
flag bit will be set and if enabled, will wake the device
from SLEEP.
15.3.9 EFFECTS OF A RESET
A RESET disables the MSSP module and terminates
the current transfer.
15.3.10 BUS MODE COMPATIBILITY
Table 15-1 shows the compatibility between the
standard SPI modes and the states the CKP and CKE
control bits.
TABLE 15-1: SPI BUS MODES
There is also a SMP bit which controls when the data is
sampled.
TABLE 15-2: REGISTERS ASSOCIATED WITH SPI OPERATION
Standard SPI Mode
Terminology
Control Bits State
CKP CKE
0, 0 0 1
0, 1 0 0
1, 0 1 1
1, 1 1 0
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
TRISC PORTC Data Direction Register 1111 1111 1111 1111
SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
TRISA — PORTA Data Direction Register -111 1111 -111 1111
SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used by the MSSP in SPI mode.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18C2X2 devices; always maintain these bits clear.PIC18FXX2
DS39564C-page 134 © 2006 Microchip Technology Inc.
15.4 I2C Mode
The MSSP module in I2C mode fully implements all
master and slave functions (including general call support)
and provides interrupts on START and STOP bits
in hardware to determine a free bus (multi-master function).
The MSSP module implements the Standard
mode specifications, as well as 7-bit and 10-bit
addressing.
Two pins are used for data transfer:
• Serial clock (SCL) - RC3/SCK/SCL
• Serial data (SDA) - RC4/SDI/SDA
The user must configure these pins as inputs or outputs
through the TRISC<4:3> bits.
FIGURE 15-7: MSSP BLOCK DIAGRAM
(I2C MODE)
15.4.1 REGISTERS
The MSSP module has six registers for I2C operation.
These are:
• MSSP Control Register1 (SSPCON1)
• MSSP Control Register2 (SSPCON2)
• MSSP Status Register (SSPSTAT)
• Serial Receive/Transmit Buffer (SSPBUF)
• MSSP Shift Register (SSPSR) - Not directly
accessible
• MSSP Address Register (SSPADD)
SSPCON, SSPCON2 and SSPSTAT are the control
and status registers in I2C mode operation. The
SSPCON and SSPCON2 registers are readable and
writable. The lower 6 bits of the SSPSTAT are read
only. The upper two bits of the SSPSTAT are read/
write.
SSPSR is the shift register used for shifting data in or
out. SSPBUF is the buffer register to which data bytes
are written to or read from.
SSPADD register holds the slave device address
when the SSP is configured in I2C Slave mode. When
the SSP is configured in Master mode, the lower
seven bits of SSPADD act as the baud rate generator
reload value.
In receive operations, SSPSR and SSPBUF together,
create a double buffered receiver. When SSPSR
receives a complete byte, it is transferred to SSPBUF
and the SSPIF interrupt is set.
During transmission, the SSPBUF is not double buffered.
A write to SSPBUF will write to both SSPBUF and
SSPSR.
Read Write
SSPSR reg
Match Detect
SSPADD reg
START and
STOP bit Detect
SSPBUF reg
Internal
Data Bus
Addr Match
Set, Reset
S, P bits
(SSPSTAT reg)
RC3/SCK/SCL
RC4/
Shift
Clock
MSb
SDI/
LSb
SDA© 2006 Microchip Technology Inc. DS39564C-page 135
PIC18FXX2
REGISTER 15-3: SSPSTAT: MSSP STATUS REGISTER (I2C MODE)
R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0
SMP CKE D/A P S R/W UA BF
bit 7 bit 0
bit 7 SMP: Slew Rate Control bit
In Master or Slave mode:
1 = Slew rate control disabled for Standard Speed mode (100 kHz and 1 MHz)
0 = Slew rate control enabled for High Speed mode (400 kHz)
bit 6 CKE: SMBus Select bit
In Master or Slave mode:
1 = Enable SMBus specific inputs
0 = Disable SMBus specific inputs
bit 5 D/A: Data/Address bit
In Master mode:
Reserved
In Slave mode:
1 = Indicates that the last byte received or transmitted was data
0 = Indicates that the last byte received or transmitted was address
bit 4 P: STOP bit
1 = Indicates that a STOP bit has been detected last
0 = STOP bit was not detected last
Note: This bit is cleared on RESET and when SSPEN is cleared.
bit 3 S: START bit
1 = Indicates that a start bit has been detected last
0 = START bit was not detected last
Note: This bit is cleared on RESET and when SSPEN is cleared.
bit 2 R/W: Read/Write bit Information (I2C mode only)
In Slave mode:
1 = Read
0 = Write
Note: This bit holds the R/W bit information following the last address match. This bit is only
valid from the address match to the next START bit, STOP bit, or not ACK bit.
In Master mode:
1 = Transmit is in progress
0 = Transmit is not in progress
Note: ORing this bit with SEN, RSEN, PEN, RCEN, or ACKEN will indicate if the MSSP is
in IDLE mode.
bit 1 UA: Update Address (10-bit Slave mode only)
1 = Indicates that the user needs to update the address in the SSPADD register
0 = Address does not need to be updated
bit 0 BF: Buffer Full Status bit
In Transmit mode:
1 = Receive complete, SSPBUF is full
0 = Receive not complete, SSPBUF is empty
In Receive mode:
1 = Data transmit in progress (does not include the ACK and STOP bits), SSPBUF is full
0 = Data transmit complete (does not include the ACK and STOP bits), SSPBUF is empty
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 136 © 2006 Microchip Technology Inc.
REGISTER 15-4: SSPCON1: MSSP CONTROL REGISTER1 (I2C MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
bit 7 bit 0
bit 7 WCOL: Write Collision Detect bit
In Master Transmit mode:
1 = A write to the SSPBUF register was attempted while the I2C conditions were not valid for
a transmission to be started (must be cleared in software)
0 = No collision
In Slave Transmit mode:
1 = The SSPBUF register is written while it is still transmitting the previous word (must be
cleared in software)
0 = No collision
In Receive mode (Master or Slave modes):
This is a “don’t care” bit
bit 6 SSPOV: Receive Overflow Indicator bit
In Receive mode:
1 = A byte is received while the SSPBUF register is still holding the previous byte (must
be cleared in software)
0 = No overflow
In Transmit mode:
This is a “don’t care” bit in Transmit mode
bit 5 SSPEN: Synchronous Serial Port Enable bit
1 = Enables the serial port and configures the SDA and SCL pins as the serial port pins
0 = Disables serial port and configures these pins as I/O port pins
Note: When enabled, the SDA and SCL pins must be properly configured as input or output.
bit 4 CKP: SCK Release Control bit
In Slave mode:
1 = Release clock
0 = Holds clock low (clock stretch), used to ensure data setup time
In Master mode:
Unused in this mode
bit 3-0 SSPM3:SSPM0: Synchronous Serial Port Mode Select bits
1111 = I2C Slave mode, 10-bit address with START and STOP bit interrupts enabled
1110 = I2C Slave mode, 7-bit address with START and STOP bit interrupts enabled
1011 = I2C Firmware Controlled Master mode (Slave IDLE)
1000 = I2C Master mode, clock = FOSC / (4 * (SSPADD+1))
0111 = I2C Slave mode, 10-bit address
0110 = I2C Slave mode, 7-bit address
Note: Bit combinations not specifically listed here are either reserved, or implemented in
SPI mode only.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 137
PIC18FXX2
REGISTER 15-5: SSPCON2: MSSP CONTROL REGISTER 2 (I2C MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
bit 7 bit 0
bit 7 GCEN: General Call Enable bit (Slave mode only)
1 = Enable interrupt when a general call address (0000h) is received in the SSPSR
0 = General call address disabled
bit 6 ACKSTAT: Acknowledge Status bit (Master Transmit mode only)
1 = Acknowledge was not received from slave
0 = Acknowledge was received from slave
bit 5 ACKDT: Acknowledge Data bit (Master Receive mode only)
1 = Not Acknowledge
0 = Acknowledge
Note: Value that will be transmitted when the user initiates an Acknowledge sequence at
the end of a receive.
bit 4 ACKEN: Acknowledge Sequence Enable bit (Master Receive mode only)
1 = Initiate Acknowledge sequence on SDA and SCL pins, and transmit ACKDT data bit.
Automatically cleared by hardware.
0 = Acknowledge sequence IDLE
bit 3 RCEN: Receive Enable bit (Master mode only)
1 = Enables Receive mode for I2C
0 = Receive IDLE
bit 2 PEN: STOP Condition Enable bit (Master mode only)
1 = Initiate STOP condition on SDA and SCL pins. Automatically cleared by hardware.
0 = STOP condition IDLE
bit 1 RSEN: Repeated START Condition Enabled bit (Master mode only)
1 = Initiate Repeated START condition on SDA and SCL pins.
Automatically cleared by hardware.
0 = Repeated START condition IDLE
bit 0 SEN: START Condition Enabled/Stretch Enabled bit
In Master mode:
1 = Initiate START condition on SDA and SCL pins. Automatically cleared by hardware.
0 = START condition IDLE
In Slave mode:
1 = Clock stretching is enabled for both Slave Transmit and Slave Receive (stretch enabled)
0 = Clock stretching is enabled for slave transmit only (Legacy mode)
Note: For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the IDLE
mode, this bit may not be set (no spooling) and the SSPBUF may not be written (or
writes to the SSPBUF are disabled).
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 138 © 2006 Microchip Technology Inc.
15.4.2 OPERATION
The MSSP module functions are enabled by setting
MSSP Enable bit, SSPEN (SSPCON<5>).
The SSPCON1 register allows control of the I2C operation.
Four mode selection bits (SSPCON<3:0>) allow
one of the following I2C modes to be selected:
• I2C Master mode, clock = OSC/4 (SSPADD +1)
• I2C Slave mode (7-bit address)
• I2C Slave mode (10-bit address)
• I2C Slave mode (7-bit address), with START and
STOP bit interrupts enabled
• I2C Slave mode (10-bit address), with START and
STOP bit interrupts enabled
• I2C Firmware controlled master operation, slave
is IDLE
Selection of any I2C mode, with the SSPEN bit set,
forces the SCL and SDA pins to be open drain, provided
these pins are programmed to inputs by setting
the appropriate TRISC bits. To guarantee proper operation
of the module, pull-up resistors must be provided
externally to the SCL and SDA pins.
15.4.3 SLAVE MODE
In Slave mode, the SCL and SDA pins must be configured
as inputs (TRISC<4:3> set). The MSSP module
will override the input state with the output data when
required (slave-transmitter).
The I2C Slave mode hardware will always generate an
interrupt on an address match. Through the mode
select bits, the user can also choose to interrupt on
START and STOP bits
When an address is matched or the data transfer after
an address match is received, the hardware automatically
will generate the Acknowledge (ACK) pulse and
load the SSPBUF register with the received value
currently in the SSPSR register.
Any combination of the following conditions will cause
the MSSP module not to give this ACK pulse:
• The buffer full bit BF (SSPSTAT<0>) was set
before the transfer was received.
• The overflow bit SSPOV (SSPCON<6>) was set
before the transfer was received.
In this case, the SSPSR register value is not loaded
into the SSPBUF, but bit SSPIF (PIR1<3>) is set. The
BF bit is cleared by reading the SSPBUF register, while
bit SSPOV is cleared through software.
The SCL clock input must have a minimum high and
low for proper operation. The high and low times of the
I
2C specification, as well as the requirement of the
MSSP module, are shown in timing parameter 100 and
parameter 101.
15.4.3.1 Addressing
Once the MSSP module has been enabled, it waits for
a START condition to occur. Following the START condition,
the 8-bits are shifted into the SSPSR register. All
incoming bits are sampled with the rising edge of the
clock (SCL) line. The value of register SSPSR<7:1> is
compared to the value of the SSPADD register. The
address is compared on the falling edge of the eighth
clock (SCL) pulse. If the addresses match, and the BF
and SSPOV bits are clear, the following events occur:
1. The SSPSR register value is loaded into the
SSPBUF register.
2. The buffer full bit BF is set.
3. An ACK pulse is generated.
4. MSSP interrupt flag bit, SSPIF (PIR1<3>) is set
(interrupt is generated if enabled) on the falling
edge of the ninth SCL pulse.
In 10-bit Address mode, two address bytes need to be
received by the slave. The five Most Significant bits
(MSbs) of the first address byte specify if this is a 10-bit
address. Bit R/W (SSPSTAT<2>) must specify a write
so the slave device will receive the second address
byte. For a 10-bit address, the first byte would equal
‘11110 A9 A8 0’, where ‘A9’ and ‘A8’ are the two
MSbs of the address. The sequence of events for 10-bit
address is as follows, with steps 7 through 9 for the
slave-transmitter:
1. Receive first (high) byte of Address (bits SSPIF,
BF and bit UA (SSPSTAT<1>) are set).
2. Update the SSPADD register with second (low)
byte of Address (clears bit UA and releases the
SCL line).
3. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
4. Receive second (low) byte of Address (bits
SSPIF, BF, and UA are set).
5. Update the SSPADD register with the first (high)
byte of Address. If match releases SCL line, this
will clear bit UA.
6. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
7. Receive Repeated START condition.
8. Receive first (high) byte of Address (bits SSPIF
and BF are set).
9. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.© 2006 Microchip Technology Inc. DS39564C-page 139
PIC18FXX2
15.4.3.2 Reception
When the R/W bit of the address byte is clear and an
address match occurs, the R/W bit of the SSPSTAT
register is cleared. The received address is loaded into
the SSPBUF register and the SDA line is held low
(ACK).
When the address byte overflow condition exists, then
the no Acknowledge (ACK) pulse is given. An overflow
condition is defined as either bit BF (SSPSTAT<0>) is
set, or bit SSPOV (SSPCON1<6>) is set.
An MSSP interrupt is generated for each data transfer
byte. Flag bit SSPIF (PIR1<3>) must be cleared in software.
The SSPSTAT register is used to determine the
status of the byte.
If SEN is enabled (SSPCON1<0>=1), RC3/SCK/SCL
will be held low (clock stretch) following each data transfer.
The clock must be released by setting bit CKP
(SSPCON<4>). See Section 15.4.4 (“Clock Stretching”),
for more detail.
15.4.3.3 Transmission
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSPSTAT register is set. The received address is
loaded into the SSPBUF register. The ACK pulse will
be sent on the ninth bit and pin RC3/SCK/SCL is held
low, regardless of SEN (see “Clock Stretching”,
Section 15.4.4, for more detail). By stretching the clock,
the master will be unable to assert another clock pulse
until the slave is done preparing the transmit data.The
transmit data must be loaded into the SSPBUF register,
which also loads the SSPSR register. Then pin RC3/
SCK/SCL should be enabled by setting bit CKP
(SSPCON1<4>). The eight data bits are shifted out on
the falling edge of the SCL input. This ensures that the
SDA signal is valid during the SCL high time
(Figure 15-9).
The ACK pulse from the master-receiver is latched on
the rising edge of the ninth SCL input pulse. If the SDA
line is high (not ACK), then the data transfer is complete.
In this case, when the ACK is latched by the
slave, the slave logic is reset (resets SSPSTAT register)
and the slave monitors for another occurrence of
the START bit. If the SDA line was low (ACK), the next
transmit data must be loaded into the SSPBUF register.
Again, pin RC3/SCK/SCL must be enabled by setting
bit CKP.
An MSSP interrupt is generated for each data transfer
byte. The SSPIF bit must be cleared in software and
the SSPSTAT register is used to determine the status
of the byte. The SSPIF bit is set on the falling edge of
the ninth clock pulse.PIC18FXX2
DS39564C-page 140 © 2006 Microchip Technology Inc.
FIGURE 15-8: I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 7-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>) SSPOV (SSPCON<6>)
S 1 2 34 56 7 8 91 234 5 67 89 1 23 45 7 89 P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0
ACK Receiving Data ACK Receiving Data R/W = 0
ACK
Receiving Address
Cleared in software
SSPBUF is read
Bus Master
terminates
transfer
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
D2
6
(PIR1<3>)
CKP (CKP does not reset to ‘0’ when SEN = 0)© 2006 Microchip Technology Inc. DS39564C-page 141
PIC18FXX2
FIGURE 15-9: I2C SLAVE MODE TIMING (TRANSMISSION, 7-BIT ADDRESS) SDA SCL SSPIF (PIR1<3>) BF (SSPSTAT<0>) A6 A5 A4 A3 A2 A1 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9
SSPBUF is written in software
Cleared in software
SCL held low
while CPU
responds to SSPIF
From SSPIF ISR
Data in
sampled
S
ACK Transmitting Data R/W = 1
ACK
Receiving Address
A7 D7
9 1
D6 D5 D4 D3 D2 D1 D0
2 3 4 5 6 7 8 9
SSPBUF is written in software
Cleared in software
From SSPIF ISR
Transmitting Data
D7
1
CKP
P
ACK
CKP is set in software CKP is set in softwarePIC18FXX2
DS39564C-page 142 © 2006 Microchip Technology Inc.
FIGURE 15-10: I2C SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 10-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>)
S 1 234 56 7 89 1 2345 67 89 1 2345 7 89 P
1 1 1 1 0 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
D2
6
(PIR1<3>)
Cleared in software
Receive Second Byte of Address
Cleared by hardware
when SSPADD is updated
with low byte of address
UA (SSPSTAT<1>)
Clock is held low until
update of SSPADD has
taken place
UA is set indicating that
the SSPADD needs to be
updated
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware when
SSPADD is updated with high
byte of address
SSPBUF is written with
contents of SSPSR
Dummy read of SSPBUF
to clear BF flag
ACK
CKP
D7 D6 D5 D4 D3 D1 D0
12345 789
Receive Data Byte
Bus Master
terminates
transfer
D2
6
ACK
Cleared in software Cleared in software
SSPOV (SSPCON<6>)
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
(CKP does not reset to ‘0’ when SEN = 0)
Clock is held low until
update of SSPADD has
taken place© 2006 Microchip Technology Inc. DS39564C-page 143
PIC18FXX2
FIGURE 15-11: I2C SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>)
S 1 234 56 789 1 2345 67 89 1 2345 789 P
1 1 1 1 0 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 1 1 1 1 0 A8
R/W=1
ACK ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
Bus Master
terminates
transfer
A9
6
(PIR1<3>)
Receive Second Byte of Address
Cleared by hardware when
SSPADD is updated with low
byte of address
UA (SSPSTAT<1>)
Clock is held low until
update of SSPADD has
taken place
UA is set indicating that
the SSPADD needs to be
updated
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware when
SSPADD is updated with high
byte of address.
SSPBUF is written with
contents of SSPSR
Dummy read of SSPBUF
to clear BF flag
Receive First Byte of Address
D7 D6 D5 D4 D3 D1
12345 789
ACK
D2
6
Transmitting Data Byte
D0
Dummy read of SSPBUF
to clear BF flag
Sr
Cleared in software
Write of SSPBUF
initiates transmit
Cleared in software
Completion of
clears BF flag
CKP (SSPCON<4>)
CKP is set in software
CKP is automatically cleared in hardware holding SCL low
Clock is held low until
update of SSPADD has
taken place
data transmission
Clock is held low until
CKP is set to ‘1’
BF flag is clear
at the end of the
third address sequencePIC18FXX2
DS39564C-page 144 © 2006 Microchip Technology Inc.
15.4.4 CLOCK STRETCHING
Both 7- and 10-bit Slave modes implement automatic
clock stretching during a transmit sequence.
The SEN bit (SSPCON2<0>) allows clock stretching to
be enabled during receives. Setting SEN will cause
the SCL pin to be held low at the end of each data
receive sequence.
15.4.4.1 Clock Stretching for 7-bit Slave
Receive Mode (SEN = 1)
In 7-bit Slave Receive mode, on the falling edge of the
ninth clock at the end of the ACK sequence, if the BF
bit is set, the CKP bit in the SSPCON1 register is automatically
cleared, forcing the SCL output to be held
low. The CKP being cleared to ‘0’ will assert the SCL
line low. The CKP bit must be set in the user’s ISR
before reception is allowed to continue. By holding the
SCL line low, the user has time to service the ISR and
read the contents of the SSPBUF before the master
device can initiate another receive sequence. This will
prevent buffer overruns from occurring (see
Figure 15-13).
15.4.4.2 Clock Stretching for 10-bit Slave
Receive Mode (SEN = 1)
In 10-bit Slave Receive mode, during the address
sequence, clock stretching automatically takes place
but CKP is not cleared. During this time, if the UA bit is
set after the ninth clock, clock stretching is initiated.
The UA bit is set after receiving the upper byte of the
10-bit address, and following the receive of the second
byte of the 10-bit address with the R/W bit cleared to
‘0’. The release of the clock line occurs upon updating
SSPADD. Clock stretching will occur on each data
receive sequence as described in 7-bit mode.
15.4.4.3 Clock Stretching for 7-bit Slave
Transmit Mode
7-bit Slave Transmit mode implements clock stretching
by clearing the CKP bit after the falling edge of the
ninth clock, if the BF bit is clear. This occurs,
regardless of the state of the SEN bit.
The user’s ISR must set the CKP bit before transmission
is allowed to continue. By holding the SCL line
low, the user has time to service the ISR and load the
contents of the SSPBUF before the master device can
initiate another transmit sequence (see Figure 15-9).
15.4.4.4 Clock Stretching for 10-bit Slave
Transmit Mode
In 10-bit Slave Transmit mode, clock stretching is controlled
during the first two address sequences by the
state of the UA bit, just as it is in 10-bit Slave Receive
mode. The first two addresses are followed by a third
address sequence, which contains the high order bits
of the 10-bit address and the R/W bit set to ‘1’. After
the third address sequence is performed, the UA bit is
not set, the module is now configured in Transmit
mode, and clock stretching is controlled by the BF flag,
as in 7-bit Slave Transmit mode (see Figure 15-11).
Note 1: If the user reads the contents of the
SSPBUF before the falling edge of the
ninth clock, thus clearing the BF bit, the
CKP bit will not be cleared and clock
stretching will not occur.
2: The CKP bit can be set in software,
regardless of the state of the BF bit. The
user should be careful to clear the BF bit
in the ISR before the next receive
sequence, in order to prevent an overflow
condition.
Note: If the user polls the UA bit and clears it by
updating the SSPADD register before the
falling edge of the ninth clock occurs, and if
the user hasn’t cleared the BF bit by reading
the SSPBUF register before that time,
then the CKP bit will still NOT be asserted
low. Clock stretching on the basis of the
state of the BF bit only occurs during a data
sequence, not an address sequence.
Note 1: If the user loads the contents of SSPBUF,
setting the BF bit before the falling edge of
the ninth clock, the CKP bit will not be
cleared and clock stretching will not occur.
2: The CKP bit can be set in software,
regardless of the state of the BF bit.© 2006 Microchip Technology Inc. DS39564C-page 145
PIC18FXX2
15.4.4.5 Clock Synchronization and
the CKP bit
If a user clears the CKP bit, the SCL output is forced to
‘0’. Setting the CKP bit will not assert the SCL output
low until the SCL output is already sampled low. If the
user attempts to drive SCL low, the CKP bit will not
assert the SCL line until an external I2C master device
has already asserted the SCL line. The SCL output will
remain low until the CKP bit is set, and all other
devices on the I2C bus have de-asserted SCL. This
ensures that a write to the CKP bit will not violate the
minimum high time requirement for SCL (see
Figure 15-12).
FIGURE 15-12: CLOCK SYNCHRONIZATION TIMING
SDA
SCL
DX DX-1
WR
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SSPCON
CKP
Master device
de-asserts clock
Master device
asserts clockPIC18FXX2
DS39564C-page 146 © 2006 Microchip Technology Inc.
FIGURE 15-13: I2C SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 7-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>) SSPOV (SSPCON<6>)
S 1 2 34 56 7 8 9 1 234 5 67 89 1 23 45 7 89 P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0
ACK Receiving Data ACK Receiving Data R/W = 0
ACK
Receiving Address
Cleared in software
SSPBUF is read
Bus Master
terminates
transfer
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
D2
6
(PIR1<3>)
CKP
CKP
written
to ‘1’ in
If BF is cleared
prior to the falling
edge of the 9th clock,
CKP will not be reset
to ‘0’ and no clock
stretching will occur
software
Clock is held low until
CKP is set to ‘1’
Clock is not held low
because buffer full bit is
clear prior to falling edge
of 9th clock
Clock is not held low
because ACK = 1
BF is set after falling
edge of the 9th clock,
CKP is reset to ‘0’ and
clock stretching occurs© 2006 Microchip Technology Inc. DS39564C-page 147
PIC18FXX2
FIGURE 15-14: I2C SLAVE MODE TIMING SEN = 1 (RECEPTION, 10-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>)
S 1 234 56 7 8 9 1 234 5 67 89 1 2345 7 89 P
1 1 1 1 0 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
D2
6
(PIR1<3>)
Cleared in software
Receive Second Byte of Address
Cleared by hardware when
SSPADD is updated with low
byte of address after falling edge
UA (SSPSTAT<1>)
Clock is held low until
update of SSPADD has
taken place
UA is set indicating that
the SSPADD needs to be
updated
UA is set indicating that
SSPADD needs to be
updated
Cleared by hardware when
SSPADD is updated with high
byte of address after falling edge
SSPBUF is written with
contents of SSPSR
Dummy read of SSPBUF
to clear BF flag
ACK
CKP
D7 D6 D5 D4 D3 D1 D0
12345 789
Receive Data Byte
Bus Master
terminates
transfer
D2
6
ACK
Cleared in software Cleared in software
SSPOV (SSPCON<6>)
CKP written to ‘1’
Note: An update of the SSPADD
register before the falling
edge of the ninth clock will
have no effect on UA, and
UA will remain set.
Note: An update of the SSPADD
register before the falling
edge of the ninth clock will
have no effect on UA, and
UA will remain set.
in software
Clock is held low until
update of SSPADD has
taken place
of ninth clock. of ninth clock.
SSPOV is set
because SSPBUF is
still full. ACK is not sent.
Dummy read of SSPBUF
to clear BF flag
Clock is held low until
CKP is set to ‘1’
Clock is not held low
because ACK = 1PIC18FXX2
DS39564C-page 148 © 2006 Microchip Technology Inc.
15.4.5 GENERAL CALL ADDRESS
SUPPORT
The addressing procedure for the I2C bus is such that
the first byte after the START condition usually determines
which device will be the slave addressed by the
master. The exception is the general call address,
which can address all devices. When this address is
used, all devices should, in theory, respond with an
Acknowledge.
The general call address is one of eight addresses
reserved for specific purposes by the I2C protocol. It
consists of all 0’s with R/W = 0.
The general call address is recognized when the General
Call Enable bit (GCEN) is enabled (SSPCON2<7>
set). Following a START bit detect, 8-bits are shifted
into the SSPSR and the address is compared against
the SSPADD. It is also compared to the general call
address and fixed in hardware.
If the general call address matches, the SSPSR is
transferred to the SSPBUF, the BF flag bit is set (eighth
bit), and on the falling edge of the ninth bit (ACK bit),
the SSPIF interrupt flag bit is set.
When the interrupt is serviced, the source for the interrupt
can be checked by reading the contents of the
SSPBUF. The value can be used to determine if the
address was device specific or a general call address.
In 10-bit mode, the SSPADD is required to be updated
for the second half of the address to match, and the UA
bit is set (SSPSTAT<1>). If the general call address is
sampled when the GCEN bit is set, while the slave is
configured in 10-bit Address mode, then the second
half of the address is not necessary, the UA bit will not
be set, and the slave will begin receiving data after the
Acknowledge (Figure 15-15).
FIGURE 15-15: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE
(7 OR 10-BIT ADDRESS MODE)
SDA
SCL
S
SSPIF
BF (SSPSTAT<0>)
SSPOV (SSPCON1<6>)
Cleared in software
SSPBUF is read
R/W = 0
ACK General Call Address
Address is compared to General Call Address
GCEN (SSPCON2<7>)
Receiving data ACK
1 2 34 56 7891 2 34 56 789
D7 D6 D5 D4 D3 D2 D1 D0
after ACK, set interrupt
'0'
'1'© 2006 Microchip Technology Inc. DS39564C-page 149
PIC18FXX2
15.4.6 MASTER MODE
Master mode is enabled by setting and clearing the
appropriate SSPM bits in SSPCON1 and by setting the
SSPEN bit. In Master mode, the SCL and SDA lines
are manipulated by the MSSP hardware.
Master mode of operation is supported by interrupt
generation on the detection of the START and STOP
conditions. The STOP (P) and START (S) bits are
cleared from a RESET or when the MSSP module is
disabled. Control of the I2C bus may be taken when the
P bit is set or the bus is IDLE, with both the S and P bits
clear.
In Firmware Controlled Master mode, user code conducts
all I2C bus operations based on START and
STOP bit conditions.
Once Master mode is enabled, the user has six
options.
1. Assert a START condition on SDA and SCL.
2. Assert a Repeated START condition on SDA
and SCL.
3. Write to the SSPBUF register initiating
transmission of data/address.
4. Configure the I2C port to receive data.
5. Generate an Acknowledge condition at the end
of a received byte of data.
6. Generate a STOP condition on SDA and SCL.
The following events will cause SSP interrupt flag bit,
SSPIF, to be set (SSP interrupt if enabled):
• START condition
• STOP condition
• Data transfer byte transmitted/received
• Acknowledge Transmit
• Repeated START
FIGURE 15-16: MSSP BLOCK DIAGRAM (I2C MASTER MODE)
Note: The MSSP Module, when configured in I2C
Master mode, does not allow queueing of
events. For instance, the user is not
allowed to initiate a START condition and
immediately write the SSPBUF register to
initiate transmission before the START
condition is complete. In this case, the
SSPBUF will not be written to and the
WCOL bit will be set, indicating that a write
to the SSPBUF did not occur.
Read Write
SSPSR
START bit, STOP bit,
START bit Detect
SSPBUF
Internal
Data Bus
Set/Reset, S, P, WCOL (SSPSTAT)
Shift
Clock
MSb LSb
SDA
Acknowledge
Generate
STOP bit Detect
Write Collision Detect
Clock Arbitration
State Counter for
end of XMIT/RCV
SCL
SCL in
Bus Collision
SDA in Receive Enable
Clock Cntl
Clock Arbitrate/WCOL Detect
(hold off clock source)
SSPADD<6:0>
Baud
Set SSPIF, BCLIF
Reset ACKSTAT, PEN (SSPCON2)
Rate
Generator
SSPM3:SSPM0PIC18FXX2
DS39564C-page 150 © 2006 Microchip Technology Inc.
15.4.6.1 I2C Master Mode Operation
The master device generates all of the serial clock
pulses and the START and STOP conditions. A transfer
is ended with a STOP condition or with a Repeated
START condition. Since the Repeated START condition
is also the beginning of the next serial transfer, the
I
2C bus will not be released.
In Master Transmitter mode, serial data is output
through SDA, while SCL outputs the serial clock. The
first byte transmitted contains the slave address of the
receiving device (7 bits) and the Read/Write (R/W) bit.
In this case, the R/W bit will be logic '0'. Serial data is
transmitted 8 bits at a time. After each byte is transmitted,
an Acknowledge bit is received. START and STOP
conditions are output to indicate the beginning and the
end of a serial transfer.
In Master Receive mode, the first byte transmitted contains
the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be
logic '1'. Thus, the first byte transmitted is a 7-bit slave
address followed by a '1' to indicate receive bit. Serial
data is received via SDA, while SCL outputs the serial
clock. Serial data is received 8 bits at a time. After each
byte is received, an Acknowledge bit is transmitted.
START and STOP conditions indicate the beginning
and end of transmission.
The baud rate generator used for the SPI mode operation
is used to set the SCL clock frequency for either
100 kHz, 400 kHz or 1 MHz I2C operation. See
Section 15.4.7 (“Baud Rate Generator”), for more
detail.
A typical transmit sequence would go as follows:
1. The user generates a START condition by setting
the START enable bit, SEN
(SSPCON2<0>).
2. SSPIF is set. The MSSP module will wait the
required start time before any other operation
takes place.
3. The user loads the SSPBUF with the slave
address to transmit.
4. Address is shifted out the SDA pin until all 8 bits
are transmitted.
5. The MSSP Module shifts in the ACK bit from the
slave device and writes its value into the
SSPCON2 register (SSPCON2<6>).
6. The MSSP module generates an interrupt at the
end of the ninth clock cycle by setting the SSPIF
bit.
7. The user loads the SSPBUF with eight bits of
data.
8. Data is shifted out the SDA pin until all 8 bits are
transmitted.
9. The MSSP Module shifts in the ACK bit from the
slave device and writes its value into the
SSPCON2 register (SSPCON2<6>).
10. The MSSP module generates an interrupt at the
end of the ninth clock cycle by setting the SSPIF
bit.
11. The user generates a STOP condition by setting
the STOP enable bit PEN (SSPCON2<2>).
12. Interrupt is generated once the STOP condition
is complete.© 2006 Microchip Technology Inc. DS39564C-page 151
PIC18FXX2
15.4.7 BAUD RATE GENERATOR
In I2C Master mode, the baud rate generator (BRG)
reload value is placed in the lower 7 bits of the
SSPADD register (Figure 15-17). When a write occurs
to SSPBUF, the baud rate generator will automatically
begin counting. The BRG counts down to 0 and stops
until another reload has taken place. The BRG count is
decremented twice per instruction cycle (TCY) on the
Q2 and Q4 clocks. In I2C Master mode, the BRG is
reloaded automatically.
Once the given operation is complete (i.e., transmission
of the last data bit is followed by ACK), the internal
clock will automatically stop counting and the SCL pin
will remain in its last state.
Table 15-3 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSPADD.
FIGURE 15-17: BAUD RATE GENERATOR BLOCK DIAGRAM
TABLE 15-3: I2C CLOCK RATE W/BRG
SSPM3:SSPM0
CLKO BRG Down Counter Fosc/4
SSPADD<6:0>
SSPM3:SSPM0
SCL
Reload
Control
Reload
FCY FCY*2 BRG Value FSCL(2)
(2 Rollovers of BRG)
10 MHz 20 MHz 19h 400 kHz(1)
10 MHz 20 MHz 20h 312.5 kHz
10 MHz 20 MHz 3Fh 100 kHz
4 MHz 8 MHz 0Ah 400 kHz(1)
4 MHz 8 MHz 0Dh 308 kHz
4 MHz 8 MHz 28h 100 kHz
1 MHz 2 MHz 03h 333 kHz(1)
1 MHz 2 MHz 0Ah 100kHz
1 MHz 2 MHz 00h 1 MHz(1)
Note 1: The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than
100 kHz) in all details, but may be used with care where higher rates are required by the application.
2: Actual frequency will depend on bus conditions. Theoretically, bus conditions will add rise time and extend
low time of clock period, producing the effective frequency.PIC18FXX2
DS39564C-page 152 © 2006 Microchip Technology Inc.
15.4.7.1 Clock Arbitration
Clock arbitration occurs when the master, during any
receive, transmit or Repeated START/STOP condition,
de-asserts the SCL pin (SCL allowed to float high).
When the SCL pin is allowed to float high, the baud rate
generator (BRG) is suspended from counting until the
SCL pin is actually sampled high. When the SCL pin is
sampled high, the baud rate generator is reloaded with
the contents of SSPADD<6:0> and begins counting.
This ensures that the SCL high time will always be at
least one BRG rollover count, in the event that the clock
is held low by an external device (Figure 15-18).
FIGURE 15-18: BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
SDA
SCL
SCL de-asserted but slave holds
DX DX-1
BRG
SCL is sampled high, reload takes
place and BRG starts its count.
03h 02h 01h 00h (hold off) 03h 02h
Reload
BRG
Value
SCL low (clock arbitration)
SCL allowed to transition high
BRG decrements on
Q2 and Q4 cycles© 2006 Microchip Technology Inc. DS39564C-page 153
PIC18FXX2
15.4.8 I2C MASTER MODE START
CONDITION TIMING
To initiate a START condition, the user sets the START
condition enable bit, SEN (SSPCON2<0>). If the SDA
and SCL pins are sampled high, the baud rate generator
is reloaded with the contents of SSPADD<6:0> and
starts its count. If SCL and SDA are both sampled high
when the baud rate generator times out (TBRG), the
SDA pin is driven low. The action of the SDA being
driven low, while SCL is high, is the START condition
and causes the S bit (SSPSTAT<3>) to be set. Following
this, the baud rate generator is reloaded with the
contents of SSPADD<6:0> and resumes its count.
When the baud rate generator times out (TBRG), the
SEN bit (SSPCON2<0>) will be automatically cleared
by hardware, the baud rate generator is suspended,
leaving the SDA line held low and the START condition
is complete.
15.4.8.1 WCOL Status Flag
If the user writes the SSPBUF when a START
sequence is in progress, the WCOL is set and the contents
of the buffer are unchanged (the write doesn’t
occur).
FIGURE 15-19: FIRST START BIT TIMING
Note: If at the beginning of the START condition,
the SDA and SCL pins are already sampled
low, or if during the START condition
the SCL line is sampled low before the
SDA line is driven low, a bus collision
occurs, the Bus Collision Interrupt Flag,
BCLIF is set, the START condition is
aborted, and the I2C module is reset into its
IDLE state.
Note: Because queueing of events is not
allowed, writing to the lower 5 bits of
SSPCON2 is disabled until the START
condition is complete.
SDA
SCL
S
TBRG
1st bit 2nd bit
TBRG
SDA = 1,
At completion of START bit, SCL = 1
TBRG Write to SSPBUF occurs here
Hardware clears SEN bit
TBRG
Write to SEN bit occurs here Set S bit (SSPSTAT<3>)
and sets SSPIF bitPIC18FXX2
DS39564C-page 154 © 2006 Microchip Technology Inc.
15.4.9 I2C MASTER MODE REPEATED
START CONDITION TIMING
A Repeated START condition occurs when the RSEN
bit (SSPCON2<1>) is programmed high and the I2C
logic module is in the IDLE state. When the RSEN bit is
set, the SCL pin is asserted low. When the SCL pin is
sampled low, the baud rate generator is loaded with the
contents of SSPADD<5:0> and begins counting. The
SDA pin is released (brought high) for one baud rate
generator count (TBRG). When the baud rate generator
times out, if SDA is sampled high, the SCL pin will be
de-asserted (brought high). When SCL is sampled
high, the baud rate generator is reloaded with the contents
of SSPADD<6:0> and begins counting. SDA and
SCL must be sampled high for one TBRG. This action is
then followed by assertion of the SDA pin (SDA = 0) for
one TBRG,
while SCL is high. Following this, the RSEN
bit (SSPCON2<1>) will be automatically cleared and
the baud rate generator will not be reloaded, leaving
the SDA pin held low. As soon as a START condition is
detected on the SDA and SCL pins, the S bit
(SSPSTAT<3>) will be set. The SSPIF bit will not be set
until the baud rate generator has timed out.
Immediately following the SSPIF bit getting set, the
user may write the SSPBUF with the 7-bit address in
7-bit mode, or the default first address in 10-bit mode.
After the first eight bits are transmitted and an ACK is
received, the user may then transmit an additional eight
bits of address (10-bit mode) or eight bits of data (7-bit
mode).
15.4.9.1 WCOL Status Flag
If the user writes the SSPBUF when a Repeated
START sequence is in progress, the WCOL is set and
the contents of the buffer are unchanged (the write
doesn’t occur).
FIGURE 15-20: REPEAT START CONDITION WAVEFORM
Note 1: If RSEN is programmed while any other
event is in progress, it will not take effect.
2: A bus collision during the Repeated
START condition occurs if:
• SDA is sampled low when SCL goes
from low to high.
• SCL goes low before SDA is
asserted low. This may indicate that
another master is attempting to
transmit a data "1".
Note: Because queueing of events is not
allowed, writing of the lower 5 bits of
SSPCON2 is disabled until the Repeated
START condition is complete.
SDA
SCL
Sr = Repeated START
Write to SSPCON2
Falling edge of ninth clock Write to SSPBUF occurs here
End of Xmit
At completion of START bit,
hardware clear RSEN bit
1st bit
Set S (SSPSTAT<3>)
TBRG
TBRG
SDA = 1,
SDA = 1,
SCL (no change)
SCL = 1
occurs here.
TBRG TBRG TBRG
and set SSPIF© 2006 Microchip Technology Inc. DS39564C-page 155
PIC18FXX2
15.4.10 I2C MASTER MODE
TRANSMISSION
Transmission of a data byte, a 7-bit address, or the
other half of a 10-bit address is accomplished by simply
writing a value to the SSPBUF register. This action will
set the buffer full flag bit, BF, and allow the baud rate
generator to begin counting and start the next transmission.
Each bit of address/data will be shifted out onto
the SDA pin after the falling edge of SCL is asserted
(see data hold time specification parameter 106). SCL
is held low for one baud rate generator rollover count
(TBRG). Data should be valid before SCL is released
high (see data setup time specification parameter 107).
When the SCL pin is released high, it is held that way
for TBRG. The data on the SDA pin must remain stable
for that duration and some hold time after the next falling
edge of SCL. After the eighth bit is shifted out (the
falling edge of the eighth clock), the BF flag is cleared
and the master releases SDA. This allows the slave
device being addressed to respond with an ACK bit
during the ninth bit time if an address match occurred
or if data was received properly. The status of ACK is
written into the ACKDT bit on the falling edge of the
ninth clock. If the master receives an Acknowledge, the
Acknowledge status bit, ACKSTAT, is cleared. If not,
the bit is set. After the ninth clock, the SSPIF bit is set
and the master clock (baud rate generator) is suspended
until the next data byte is loaded into the
SSPBUF, leaving SCL low and SDA unchanged
(Figure 15-21).
After the write to the SSPBUF, each bit of address will
be shifted out on the falling edge of SCL until all seven
address bits and the R/W bit are completed. On the falling
edge of the eighth clock, the master will de-assert
the SDA pin, allowing the slave to respond with an
Acknowledge. On the falling edge of the ninth clock, the
master will sample the SDA pin to see if the address
was recognized by a slave. The status of the ACK bit is
loaded into the ACKSTAT status bit (SSPCON2<6>).
Following the falling edge of the ninth clock transmission
of the address, the SSPIF is set, the BF flag is
cleared and the baud rate generator is turned off until
another write to the SSPBUF takes place, holding SCL
low and allowing SDA to float.
15.4.10.1 BF Status Flag
In Transmit mode, the BF bit (SSPSTAT<0>) is set
when the CPU writes to SSPBUF and is cleared when
all 8 bits are shifted out.
15.4.10.2 WCOL Status Flag
If the user writes the SSPBUF when a transmit is
already in progress (i.e., SSPSR is still shifting out a
data byte), the WCOL is set and the contents of the
buffer are unchanged (the write doesn’t occur).
WCOL must be cleared in software.
15.4.10.3 ACKSTAT Status Flag
In Transmit mode, the ACKSTAT bit (SSPCON2<6>) is
cleared when the slave has sent an Acknowledge (ACK
= 0), and is set when the slave does not Acknowledge
(ACK = 1). A slave sends an Acknowledge when it has
recognized its address (including a general call) or
when the slave has properly received its data.
15.4.11 I2C MASTER MODE RECEPTION
Master mode reception is enabled by programming the
receive enable bit, RCEN (SSPCON2<3>).
The baud rate generator begins counting, and on each
rollover, the state of the SCL pin changes (high to low/
low to high) and data is shifted into the SSPSR. After
the falling edge of the eighth clock, the receive enable
flag is automatically cleared, the contents of the
SSPSR are loaded into the SSPBUF, the BF flag bit is
set, the SSPIF flag bit is set and the baud rate generator
is suspended from counting, holding SCL low. The
MSSP is now in IDLE state, awaiting the next command.
When the buffer is read by the CPU, the BF flag
bit is automatically cleared. The user can then send an
Acknowledge bit at the end of reception, by setting the
Acknowledge sequence enable bit, ACKEN
(SSPCON2<4>).
15.4.11.1 BF Status Flag
In receive operation, the BF bit is set when an address
or data byte is loaded into SSPBUF from SSPSR. It is
cleared when the SSPBUF register is read.
15.4.11.2 SSPOV Status Flag
In receive operation, the SSPOV bit is set when 8 bits
are received into the SSPSR and the BF flag bit is
already set from a previous reception.
15.4.11.3 WCOL Status Flag
If the user writes the SSPBUF when a receive is
already in progress (i.e., SSPSR is still shifting in a data
byte), the WCOL bit is set and the contents of the buffer
are unchanged (the write doesn’t occur).
Note: In the MSSP module, the RCEN bit must
be set after the ACK sequence or the
RCEN bit will be disregarded. PIC18FXX2
DS39564C-page 156 © 2006 Microchip Technology Inc.
FIGURE 15-21: I2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS) SDA SCL SSPIF BF (SSPSTAT<0>) SEN A7 A6 A5 A4 A3 A2 A1 ACK = 0 D7 D6 D5 D4 D3 D2 D1 D0 ACK Transmitting Data or Second Half R/W = 0 Transmit Address to Slave 123456789 123456789 P Cleared in software service routine From SSP interrupt SSPBUF is written in software After START condition, SEN cleared by hardware
S
SSPBUF written with 7-bit address and R/W
start transmit
SCL held low
while CPU
responds to SSPIF
SEN = 0
of 10-bit Address
Write SSPCON2<0> SEN = 1
START condition begins From slave clear ACKSTAT bit SSPCON2<6>
ACKSTAT in
SSPCON2 = 1
Cleared in software
SSPBUF written
PEN
Cleared in software
R/W© 2006 Microchip Technology Inc. DS39564C-page 157
PIC18FXX2
FIGURE 15-22: I2C MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)
P 9 8 7 6 5
D0 D1 D2 D3 D4 D5 D6 D7
S
A7 A6 A5 A4 A3 A2 A1 SDA
SCL 1 2 3 4 5 6 7 8 9 1 2 3 4 5 678 9 1234
Bus Master
terminates
transfer
ACK
Receiving Data from Slave Receiving Data from Slave
D0 D1 D2 D3 D4 D5 D6 D7 ACK
R/W = 1 Transmit Address to Slave
SSPIF
BF
ACK is not sent
Write to SSPCON2<0> (SEN = 1)
Write to SSPBUF occurs here
ACK from Slave
Master configured as a receiver
by programming SSPCON2<3>, (RCEN = 1)
PEN bit = 1
written here
Data shifted in on falling edge of CLK
Cleared in software
Start XMIT
SEN = 0
SDA = 0, SCL = 1
SSPOV
while CPU
(SSPSTAT<0>)
ACK
Last bit is shifted into SSPSR and
contents are unloaded into SSPBUF
Cleared in software Cleared in software
Set SSPIF interrupt
at end of receive
Set P bit
(SSPSTAT<4>)
and SSPIF
Cleared in
software
ACK from Master
Set SSPIF at end
Set SSPIF interrupt
at end of Acknowledge
sequence
Set SSPIF interrupt
at end of Acknowledge
sequence
of receive
Set ACKEN, start Acknowledge sequence
SSPOV is set because
SSPBUF is still full
SDA = ACKDT = 1
RCEN cleared
automatically
RCEN = 1 start
next receive
Write to SSPCON2<4>
to start Acknowledge sequence
SDA = ACKDT (SSPCON2<5>) = 0
RCEN cleared
automatically
responds to SSPIF
ACKEN
Begin START Condition
Cleared in software
SDA = ACKDT = 0 PIC18FXX2
DS39564C-page 158 © 2006 Microchip Technology Inc.
15.4.12 ACKNOWLEDGE SEQUENCE
TIMING
An Acknowledge sequence is enabled by setting the
Acknowledge sequence enable bit, ACKEN
(SSPCON2<4>). When this bit is set, the SCL pin is
pulled low and the contents of the Acknowledge data bit
are presented on the SDA pin. If the user wishes to generate
an Acknowledge, then the ACKDT bit should be
cleared. If not, the user should set the ACKDT bit before
starting an Acknowledge sequence. The baud rate generator
then counts for one rollover period (TBRG) and the
SCL pin is de-asserted (pulled high). When the SCL pin
is sampled high (clock arbitration), the baud rate generator
counts for TBRG. The SCL pin is then pulled low. Following
this, the ACKEN bit is automatically cleared, the
baud rate generator is turned off and the MSSP module
then goes into IDLE mode (Figure 15-23).
15.4.12.1 WCOL Status Flag
If the user writes the SSPBUF when an Acknowledge
sequence is in progress, then WCOL is set and the contents
of the buffer are unchanged (the write doesn’t occur).
15.4.13 STOP CONDITION TIMING
A STOP bit is asserted on the SDA pin at the end of a
receive/transmit by setting the STOP sequence enable
bit, PEN (SSPCON2<2>). At the end of a receive/transmit
the SCL line is held low after the falling edge of the
ninth clock. When the PEN bit is set, the master will
assert the SDA line low. When the SDA line is sampled
low, the baud rate generator is reloaded and counts
down to 0. When the baud rate generator times out, the
SCL pin will be brought high, and one TBRG (baud rate
generator rollover count) later, the SDA pin will be
de-asserted. When the SDA pin is sampled high while
SCL is high, the P bit (SSPSTAT<4>) is set. A TBRG
later, the PEN bit is cleared and the SSPIF bit is set
(Figure 15-24).
15.4.13.1 WCOL Status Flag
If the user writes the SSPBUF when a STOP sequence
is in progress, then the WCOL bit is set and the contents
of the buffer are unchanged (the write doesn’t
occur).
FIGURE 15-23: ACKNOWLEDGE SEQUENCE WAVEFORM
FIGURE 15-24: STOP CONDITION RECEIVE OR TRANSMIT MODE
Note: TBRG = one baud rate generator period.
SDA
SCL
Set SSPIF at the end
Acknowledge sequence starts here,
Write to SSPCON2 ACKEN automatically cleared
Cleared in
TBRG TBRG
of receive
ACK
8
ACKEN = 1, ACKDT = 0
D0
9
SSPIF
software Set SSPIF at the end
of Acknowledge sequence
Cleared in
software
SCL
SDA
SDA asserted low before rising edge of clock
Write to SSPCON2
Set PEN
Falling edge of
SCL = 1 for TBRG, followed by SDA = 1 for TBRG
9th clock
SCL brought high after TBRG
Note: TBRG = one baud rate generator period.
TBRG TBRG
after SDA sampled high. P bit (SSPSTAT<4>) is set.
TBRG
to setup STOP condition.
ACK
P
TBRG
PEN bit (SSPCON2<2>) is cleared by
hardware and the SSPIF bit is set© 2006 Microchip Technology Inc. DS39564C-page 159
PIC18FXX2
15.4.14 SLEEP OPERATION
While in SLEEP mode, the I2C module can receive
addresses or data, and when an address match or
complete byte transfer occurs, wake the processor
from SLEEP (if the MSSP interrupt is enabled).
15.4.15 EFFECT OF A RESET
A RESET disables the MSSP module and terminates
the current transfer.
15.4.16 MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the
detection of the START and STOP conditions allows the
determination of when the bus is free. The STOP (P)
and START (S) bits are cleared from a RESET or when
the MSSP module is disabled. Control of the I2C bus
may be taken when the P bit (SSPSTAT<4>) is set, or
the bus is idle with both the S and P bits clear. When the
bus is busy, enabling the SSP interrupt will generate the
interrupt when the STOP condition occurs.
In multi-master operation, the SDA line must be monitored
for arbitration, to see if the signal level is the
expected output level. This check is performed in
hardware, with the result placed in the BCLIF bit.
The states where arbitration can be lost are:
• Address Transfer
• Data Transfer
• A START Condition
• A Repeated START Condition
• An Acknowledge Condition
15.4.17 MULTI -MASTER COMMUNICATION,
BUS COLLISION, AND BUS
ARBITRATION
Multi-Master mode support is achieved by bus arbitration.
When the master outputs address/data bits onto
the SDA pin, arbitration takes place when the master
outputs a '1' on SDA, by letting SDA float high and
another master asserts a '0'. When the SCL pin floats
high, data should be stable. If the expected data on
SDA is a '1' and the data sampled on the SDA pin = '0',
then a bus collision has taken place. The master will set
the Bus Collision Interrupt Flag BCLIF and reset the I2C
port to its IDLE state (Figure 15-25).
If a transmit was in progress when the bus collision
occurred, the transmission is halted, the BF flag is
cleared, the SDA and SCL lines are de-asserted, and
the SSPBUF can be written to. When the user services
the bus collision Interrupt Service Routine, and if the
I
2C bus is free, the user can resume communication by
asserting a START condition.
If a START, Repeated START, STOP, or Acknowledge
condition was in progress when the bus collision
occurred, the condition is aborted, the SDA and SCL
lines are de-asserted, and the respective control bits in
the SSPCON2 register are cleared. When the user services
the bus collision Interrupt Service Routine, and if
the I2C bus is free, the user can resume communication
by asserting a START condition.
The master will continue to monitor the SDA and SCL
pins. If a STOP condition occurs, the SSPIF bit will be set.
A write to the SSPBUF will start the transmission of
data at the first data bit, regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the
detection of START and STOP conditions allows the
determination of when the bus is free. Control of the I2C
bus can be taken when the P bit is set in the SSPSTAT
register, or the bus is IDLE and the S and P bits are
cleared.
FIGURE 15-25: BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE
SDA
SCL
BCLIF
SDA released
SDA line pulled low
by another source
Sample SDA. While SCL is high,
data doesn’t match what is driven
Bus collision has occurred.
Set bus collision
interrupt (BCLIF)
by the master.
by master
Data changes
while SCL = 0PIC18FXX2
DS39564C-page 160 © 2006 Microchip Technology Inc.
15.4.17.1 Bus Collision During a START
Condition
During a START condition, a bus collision occurs if:
a) SDA or SCL are sampled low at the beginning of
the START condition (Figure 15-26).
b) SCL is sampled low before SDA is asserted low
(Figure 15-27).
During a START condition, both the SDA and the SCL
pins are monitored.
If the SDA pin is already low, or the SCL pin is already
low, then all of the following occur:
• the START condition is aborted,
• the BCLIF flag is set, and
• the MSSP module is reset to its IDLE state
(Figure 15-26).
The START condition begins with the SDA and SCL
pins de-asserted. When the SDA pin is sampled high,
the baud rate generator is loaded from SSPADD<6:0>
and counts down to 0. If the SCL pin is sampled low
while SDA is high, a bus collision occurs, because it is
assumed that another master is attempting to drive a
data '1' during the START condition.
If the SDA pin is sampled low during this count, the
BRG is reset and the SDA line is asserted early
(Figure 15-28). If, however, a '1' is sampled on the SDA
pin, the SDA pin is asserted low at the end of the BRG
count. The baud rate generator is then reloaded and
counts down to 0, and during this time, if the SCL pins
are sampled as '0', a bus collision does not occur. At
the end of the BRG count, the SCL pin is asserted low.
FIGURE 15-26: BUS COLLISION DURING START CONDITION (SDA ONLY)
Note: The reason that bus collision is not a factor
during a START condition is that no two
bus masters can assert a START condition
at the exact same time. Therefore, one
master will always assert SDA before the
other. This condition does not cause a bus
collision, because the two masters must be
allowed to arbitrate the first address following
the START condition. If the address is
the same, arbitration must be allowed to
continue into the data portion, Repeated
START or STOP conditions.
SDA
SCL
SEN
SDA sampled low before
SDA goes low before the SEN bit is set.
S bit and SSPIF set because
SSP module reset into IDLE state.
SEN cleared automatically because of bus collision.
S bit and SSPIF set because
Set SEN, enable START
condition if SDA = 1, SCL=1
SDA = 0, SCL = 1.
BCLIF
S
SSPIF
SDA = 0, SCL = 1.
SSPIF and BCLIF are
cleared in software.
SSPIF and BCLIF are
cleared in software.
Set BCLIF,
START condition. Set BCLIF.© 2006 Microchip Technology Inc. DS39564C-page 161
PIC18FXX2
FIGURE 15-27: BUS COLLISION DURING START CONDITION (SCL = 0)
FIGURE 15-28: BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION
SDA
SCL
SEN bus collision occurs. set BCLIF
SCL = 0 before SDA = 0,
Set SEN, enable START
sequence if SDA = 1, SCL = 1
TBRG TBRG
SDA = 0, SCL = 1
BCLIF
S
SSPIF
Interrupt cleared
in software
bus collision occurs. Set BCLIF.
SCL = 0 before BRG time-out,
'0' '0'
'0' '0'
SDA
SCL
SEN
Set S
Set SEN, enable START
sequence if SDA = 1, SCL = 1
Less than TBRG TBRG
SDA = 0, SCL = 1
BCLIF
S
SSPIF
S
Interrupts cleared
Set SSPIF in software
SDA = 0, SCL = 1
SDA pulled low by other master.
Reset BRG and assert SDA.
SCL pulled low after BRG
Time-out
Set SSPIF
'0'PIC18FXX2
DS39564C-page 162 © 2006 Microchip Technology Inc.
15.4.17.2 Bus Collision During a Repeated
START Condition
During a Repeated START condition, a bus collision
occurs if:
a) A low level is sampled on SDA when SCL goes
from low level to high level.
b) SCL goes low before SDA is asserted low, indicating
that another master is attempting to
transmit a data ’1’.
When the user de-asserts SDA and the pin is allowed
to float high, the BRG is loaded with SSPADD<6:0>
and counts down to 0. The SCL pin is then de-asserted,
and when sampled high, the SDA pin is sampled.
If SDA is low, a bus collision has occurred (i.e., another
master is attempting to transmit a data ’0’,
Figure 15-29). If SDA is sampled high, the BRG is
reloaded and begins counting. If SDA goes from high to
low before the BRG times out, no bus collision occurs
because no two masters can assert SDA at exactly the
same time.
If SCL goes from high to low before the BRG times out
and SDA has not already been asserted, a bus collision
occurs. In this case, another master is attempting to
transmit a data ’1’ during the Repeated START
condition, Figure 15-30.
If, at the end of the BRG time-out both SCL and SDA
are still high, the SDA pin is driven low and the BRG is
reloaded and begins counting. At the end of the count,
regardless of the status of the SCL pin, the SCL pin is
driven low and the Repeated START condition is
complete.
FIGURE 15-29: BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
FIGURE 15-30: BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
SDA
SCL
RSEN
BCLIF
S
SSPIF
Sample SDA when SCL goes high.
If SDA = 0, set BCLIF and release SDA and SCL.
Cleared in software
'0'
'0'
SDA
SCL
BCLIF
RSEN
S
SSPIF
Interrupt cleared
in software
SCL goes low before SDA,
Set BCLIF. Release SDA and SCL.
TBRG TBRG
'0'© 2006 Microchip Technology Inc. DS39564C-page 163
PIC18FXX2
15.4.17.3 Bus Collision During a STOP
Condition
Bus collision occurs during a STOP condition if:
a) After the SDA pin has been de-asserted and
allowed to float high, SDA is sampled low after
the BRG has timed out.
b) After the SCL pin is de-asserted, SCL is
sampled low before SDA goes high.
The STOP condition begins with SDA asserted low.
When SDA is sampled low, the SCL pin is allowed to
float. When the pin is sampled high (clock arbitration),
the baud rate generator is loaded with SSPADD<6:0>
and counts down to 0. After the BRG times out, SDA is
sampled. If SDA is sampled low, a bus collision has
occurred. This is due to another master attempting to
drive a data '0' (Figure 15-31). If the SCL pin is sampled
low before SDA is allowed to float high, a bus collision
occurs. This is another case of another master
attempting to drive a data '0' (Figure 15-32).
FIGURE 15-31: BUS COLLISION DURING A STOP CONDITION (CASE 1)
FIGURE 15-32: BUS COLLISION DURING A STOP CONDITION (CASE 2)
SDA
SCL
BCLIF
PEN
P
SSPIF
TBRG TBRG TBRG
SDA asserted low
SDA sampled
low after TBRG,
Set BCLIF
'0'
'0'
SDA
SCL
BCLIF
PEN
P
SSPIF
TBRG TBRG TBRG
Assert SDA SCL goes low before SDA goes high
Set BCLIF
'0'
'0'PIC18FXX2
DS39564C-page 164 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 165
PIC18FXX2
16.0 ADDRESSABLE UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (USART)
The Universal Synchronous Asynchronous Receiver
Transmitter (USART) module is one of the two serial
I/O modules. (USART is also known as a Serial Communications
Interface or SCI.) The USART can be configured
as a full duplex asynchronous system that can
communicate with peripheral devices, such as CRT terminals
and personal computers, or it can be configured
as a half-duplex synchronous system that can communicate
with peripheral devices, such as A/D or D/A
integrated circuits, serial EEPROMs, etc.
The USART can be configured in the following modes:
• Asynchronous (full-duplex)
• Synchronous - Master (half-duplex)
• Synchronous - Slave (half-duplex)
In order to configure pins RC6/TX/CK and RC7/RX/DT
as the Universal Synchronous Asynchronous Receiver
Transmitter:
• bit SPEN (RCSTA<7>) must be set (= 1),
• bit TRISC<6> must be cleared (= 0), and
• bit TRISC<7> must be set (=1).
Register 16-1 shows the Transmit Status and Control
Register (TXSTA) and Register 16-2 shows the
Receive Status and Control Register (RCSTA).PIC18FXX2
DS39564C-page 166 © 2006 Microchip Technology Inc.
REGISTER 16-1: TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R-1 R/W-0
CSRC TX9 TXEN SYNC — BRGH TRMT TX9D
bit 7 bit 0
bit 7 CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6 TX9: 9-bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5 TXEN: Transmit Enable bit
1 = Transmit enabled
0 = Transmit disabled
Note: SREN/CREN overrides TXEN in SYNC mode.
bit 4 SYNC: USART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3 Unimplemented: Read as '0'
bit 2 BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode
bit 1 TRMT: Transmit Shift Register Status bit
1 = TSR empty
0 = TSR full
bit 0 TX9D: 9th bit of Transmit Data
Can be Address/Data bit or a parity bit.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown© 2006 Microchip Technology Inc. DS39564C-page 167
PIC18FXX2
REGISTER 16-2: RCSTA: RECEIVE STATUS AND CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0 R-0 R-x
SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
bit 7 bit 0
bit 7 SPEN: Serial Port Enable bit
1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port disabled
bit 6 RX9: 9-bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5 SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care
Synchronous mode - Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode - Slave:
Don’t care
bit 4 CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3 ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enable interrupt and load of the receive buffer
when RSR<8> is set
0 = Disables address detection, all bytes are received, and ninth bit can be used as parity bit
bit 2 FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receive next valid byte)
0 = No framing error
bit 1 OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit CREN)
0 = No overrun error
bit 0 RX9D: 9th bit of Received Data
This can be Address/Data bit or a parity bit, and must be calculated by user firmware.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 168 © 2006 Microchip Technology Inc.
16.1 USART Baud Rate Generator
(BRG)
The BRG supports both the Asynchronous and Synchronous
modes of the USART. It is a dedicated 8-bit
baud rate generator. The SPBRG register controls the
period of a free running 8-bit timer. In Asynchronous
mode, bit BRGH (TXSTA<2>) also controls the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 16-1 shows the formula for computation of the
baud rate for different USART modes, which only apply
in Master mode (internal clock).
Given the desired baud rate and Fosc, the nearest integer
value for the SPBRG register can be calculated
using the formula in Table 16-1. From this, the error in
baud rate can be determined.
Example 16-1 shows the calculation of the baud rate
error for the following conditions:
• FOSC = 16 MHz
• Desired Baud Rate = 9600
• BRGH = 0
• SYNC = 0
It may be advantageous to use the high baud rate
(BRGH = 1) even for slower baud clocks. This is
because the FOSC/(16(X + 1)) equation can reduce the
baud rate error in some cases.
Writing a new value to the SPBRG register causes the
BRG timer to be reset (or cleared). This ensures the
BRG does not wait for a timer overflow before
outputting the new baud rate.
16.1.1 SAMPLING
The data on the RC7/RX/DT pin is sampled three times
by a majority detect circuit to determine if a high or a
low level is present at the RX pin.
EXAMPLE 16-1: CALCULATING BAUD RATE ERROR
TABLE 16-1: BAUD RATE FORMULA
TABLE 16-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Desired Baud Rate = FOSC / (64 (X + 1))
Solving for X:
X = ( (FOSC / Desired Baud Rate) / 64 ) – 1
X = ((16000000 / 9600) / 64) – 1
X = [25.042] = 25
Calculated Baud Rate = 16000000 / (64 (25 + 1))
= 9615
Error = (Calculated Baud Rate – Desired Baud Rate)
Desired Baud Rate
= (9615 – 9600) / 9600
= 0.16%
SYNC BRGH = 0 (Low Speed) BRGH = 1 (High Speed)
0
1
(Asynchronous) Baud Rate = FOSC/(64(X+1))
(Synchronous) Baud Rate = FOSC/(4(X+1))
Baud Rate = FOSC/(16(X+1))
N/A
Legend: X = value in SPBRG (0 to 255)
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used by the BRG.© 2006 Microchip Technology Inc. DS39564C-page 169
PIC18FXX2
TABLE 16-3: BAUD RATES FOR SYNCHRONOUS MODE
BAUD
RATE
(Kbps)
FOSC = 40 MHz SPBRG
value
(decimal)
33 MHz SPBRG
value
(decimal)
25 MHz SPBRG
value
(decimal)
20 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - NA - - NA - - NA - -
9.6 NA - - NA - - NA - - NA - -
19.2 NA - - NA - - NA - - NA - -
76.8 76.92 +0.16 129 77.10 +0.39 106 77.16 +0.47 80 76.92 +0.16 64
96 96.15 +0.16 103 95.93 -0.07 85 96.15 +0.16 64 96.15 +0.16 51
300 303.03 +1.01 32 294.64 -1.79 27 297.62 -0.79 20 294.12 -1.96 16
500 500 0 19 485.30 -2.94 16 480.77 -3.85 12 500 0 9
HIGH 10000 - 0 8250 - 0 6250 - 0 5000 - 0
LOW 39.06 - 255 32.23 - 255 24.41 - 255 19.53 - 255
BAUD
RATE
(Kbps)
FOSC = 16 MHz SPBRG
value
(decimal)
10 MHz SPBRG
value
(decimal)
7.15909 MHz SPBRG
value
(decimal)
5.0688 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - NA - - NA - - NA - -
9.6 NA - - NA - - 9.62 +0.23 185 9.60 0 131
19.2 19.23 +0.16 207 19.23 +0.16 129 19.24 +0.23 92 19.20 0 65
76.8 76.92 +0.16 51 75.76 -1.36 32 77.82 +1.32 22 74.54 -2.94 16
96 95.24 -0.79 41 96.15 +0.16 25 94.20 -1.88 18 97.48 +1.54 12
300 307.70 +2.56 12 312.50 +4.17 7 298.35 -0.57 5 316.80 +5.60 3
500 500 0 7 500 0 4 447.44 -10.51 3 422.40 -15.52 2
HIGH 4000 - 0 2500 - 0 1789.80 - 0 1267.20 - 0
LOW 15.63 - 255 9.77 - 255 6.99 - 255 4.95 - 255
BAUD
RATE
(Kbps)
FOSC = 4 MHz SPBRG
value
(decimal)
3.579545 MHz SPBRG
value
(decimal)
1 MHz SPBRG
value
(decimal)
32.768 kHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - 0.30 +1.14 26
1.2 NA - - NA - - 1.20 +0.16 207 1.17 -2.48 6
2.4 NA - - NA - - 2.40 +0.16 103 2.73 +13.78 2
9.6 9.62 +0.16 103 9.62 +0.23 92 9.62 +0.16 25 8.20 -14.67 0
19.2 19.23 +0.16 51 19.04 -0.83 46 19.23 +0.16 12 NA - -
76.8 76.92 +0.16 12 74.57 -2.90 11 83.33 +8.51 2 NA - -
96 1000 +4.17 9 99.43 +3.57 8 83.33 -13.19 2 NA - -
300 333.33 +11.11 2 298.30 -0.57 2 250 -16.67 0 NA - -
500 500 0 1 447.44 -10.51 1 NA - - NA - -
HIGH 1000 - 0 894.89 - 0 250 - 0 8.20 - 0
LOW 3.91 - 255 3.50 - 255 0.98 - 255 0.03 - 255PIC18FXX2
DS39564C-page 170 © 2006 Microchip Technology Inc.
TABLE 16-4: BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 0)
BAUD
RATE
(Kbps)
FOSC = 40 MHz SPBRG
value
(decimal)
33 MHz SPBRG
value
(decimal)
25 MHz SPBRG
value
(decimal)
20 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - 2.40 -0.07 214 2.40 -0.15 162 2.40 +0.16 129
9.6 9.62 +0.16 64 9.55 -0.54 53 9.53 -0.76 40 9.47 -1.36 32
19.2 18.94 -1.36 32 19.10 -0.54 26 19.53 +1.73 19 19.53 +1.73 15
76.8 78.13 +1.73 7 73.66 -4.09 6 78.13 +1.73 4 78.13 +1.73 3
96 89.29 -6.99 6 103.13 +7.42 4 97.66 +1.73 3 104.17 +8.51 2
300 312.50 +4.17 1 257.81 -14.06 1 NA - - 312.50 +4.17 0
500 625 +25.00 0 NA - - NA - - NA - -
HIGH 625 - 0 515.63 - 0 390.63 - 0 312.50 - 0
LOW 2.44 - 255 2.01 - 255 1.53 - 255 1.22 - 255
BAUD
RATE
(Kbps)
FOSC = 16 MHz SPBRG
value
(decimal)
10 MHz SPBRG
value
(decimal)
7.15909 MHz SPBRG
value
(decimal)
5.0688 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 1.20 +0.16 207 1.20 +0.16 129 1.20 +0.23 92 1.20 0 65
2.4 2.40 +0.16 103 2.40 +0.16 64 2.38 -0.83 46 2.40 0 32
9.6 9.62 +0.16 25 9.77 +1.73 15 9.32 -2.90 11 9.90 +3.13 7
19.2 19.23 +0.16 12 19.53 +1.73 7 18.64 -2.90 5 19.80 +3.13 3
76.8 83.33 +8.51 2 78.13 +1.73 1 111.86 +45.65 0 79.20 +3.13 0
96 83.33 -13.19 2 78.13 -18.62 1 NA - - NA - -
300 250 -16.67 0 156.25 -47.92 0 NA - - NA - -
500 NA - - NA - - NA - - NA - -
HIGH 250 - 0 156.25 - 0 111.86 - 0 79.20 - 0
LOW 0.98 - 255 0.61 - 255 0.44 - 255 0.31 - 255
BAUD
RATE
(Kbps)
FOSC = 4 MHz SPBRG
value
(decimal)
3.579545 MHz SPBRG
value
(decimal)
1 MHz SPBRG
value
(decimal)
32.768 kHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 0.30 -0.16 207 0.30 +0.23 185 0.30 +0.16 51 0.26 -14.67 1
1.2 1.20 +1.67 51 1.19 -0.83 46 1.20 +0.16 12 NA - -
2.4 2.40 +1.67 25 2.43 +1.32 22 2.23 -6.99 6 NA - -
9.6 8.93 -6.99 6 9.32 -2.90 5 7.81 -18.62 1 NA - -
19.2 20.83 +8.51 2 18.64 -2.90 2 15.63 -18.62 0 NA - -
76.8 62.50 -18.62 0 55.93 -27.17 0 NA - - NA - -
96 NA - - NA - - NA - - NA - -
300 NA - - NA - - NA - - NA - -
500 NA - - NA - - NA - - NA - -
HIGH 62.50 - 0 55.93 - 0 15.63 - 0 0.51 - 0
LOW 0.24 - 255 0.22 - 255 0.06 - 255 0.002 - 255© 2006 Microchip Technology Inc. DS39564C-page 171
PIC18FXX2
TABLE 16-5: BAUD RATES FOR ASYNCHRONOUS MODE (BRGH = 1)
BAUD
RATE
(Kbps)
FOSC = 40 MHz SPBRG
value
(decimal)
33 MHz SPBRG
value
(decimal)
25 MHz SPBRG
value
(decimal)
20 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - NA - - NA - - NA - -
9.6 NA - - 9.60 -0.07 214 9.59 -0.15 162 9.62 +0.16 129
19.2 19.23 +0.16 129 19.28 +0.39 106 19.30 +0.47 80 19.23 +0.16 64
76.8 75.76 -1.36 32 76.39 -0.54 26 78.13 +1.73 19 78.13 +1.73 15
96 96.15 +0.16 25 98.21 +2.31 20 97.66 +1.73 15 96.15 +0.16 12
300 312.50 +4.17 7 294.64 -1.79 6 312.50 +4.17 4 312.50 +4.17 3
500 500 0 4 515.63 +3.13 3 520.83 +4.17 2 416.67 -16.67 2
HIGH 2500 - 0 2062.50 - 0 1562.50 - 0 1250 - 0
LOW 9.77 - 255 8,06 - 255 6.10 - 255 4.88 - 255
BAUD
RATE
(Kbps)
FOSC = 16 MHz SPBRG
value
(decimal)
10 MHz SPBRG
value
(decimal)
7.15909 MHz SPBRG
value
(decimal)
5.0688 MHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - NA - - NA - -
1.2 NA - - NA - - NA - - NA - -
2.4 NA - - NA - - 2.41 +0.23 185 2.40 0 131
9.6 9.62 +0.16 103 9.62 +0.16 64 9.52 -0.83 46 9.60 0 32
19.2 19.23 +0.16 51 18.94 -1.36 32 19.45 +1.32 22 18.64 -2.94 16
76.8 76.92 +0.16 12 78.13 +1.73 7 74.57 -2.90 5 79.20 +3.13 3
96 100 +4.17 9 89.29 -6.99 6 89.49 -6.78 4 105.60 +10.00 2
300 333.33 +11.11 2 312.50 +4.17 1 447.44 +49.15 0 316.80 +5.60 0
500 500 0 1 625 +25.00 0 447.44 -10.51 0 NA - -
HIGH 1000 - 0 625 - 0 447.44 - 0 316.80 - 0
LOW 3.91 - 255 2.44 - 255 1.75 - 255 1.24 - 255
BAUD
RATE
(Kbps)
FOSC = 4 MHz SPBRG
value
(decimal)
3.579545 MHz SPBRG
value
(decimal)
1 MHz SPBRG
value
(decimal)
32.768 kHz SPBRG
value
(decimal) KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR KBAUD
%
ERROR
0.3 NA - - NA - - 0.30 +0.16 207 0.29 -2.48 6
1.2 1.20 +0.16 207 1.20 +0.23 185 1.20 +0.16 51 1.02 -14.67 1
2.4 2.40 +0.16 103 2.41 +0.23 92 2.40 +0.16 25 2.05 -14.67 0
9.6 9.62 +0.16 25 9.73 +1.32 22 8.93 -6.99 6 NA - -
19.2 19.23 +0.16 12 18.64 -2.90 11 20.83 +8.51 2 NA - -
76.8 NA - - 74.57 -2.90 2 62.50 -18.62 0 NA - -
96 NA - - 111.86 +16.52 1 NA - - NA - -
300 NA - - 223.72 -25.43 0 NA - - NA - -
500 NA - - NA - - NA - - NA - -
HIGH 250 - 0 55.93 - 0 62.50 - 0 2.05 - 0
LOW 0.98 - 255 0.22 - 255 0.24 - 255 0.008 - 255PIC18FXX2
DS39564C-page 172 © 2006 Microchip Technology Inc.
16.2 USART Asynchronous Mode
In this mode, the USART uses standard non-return-tozero
(NRZ) format (one START bit, eight or nine data
bits and one STOP bit). The most common data format
is 8-bits. An on-chip dedicated 8-bit baud rate generator
can be used to derive standard baud rate frequencies
from the oscillator. The USART transmits and
receives the LSb first. The USART’s transmitter and
receiver are functionally independent, but use the
same data format and baud rate. The baud rate generator
produces a clock, either x16 or x64 of the bit shift
rate, depending on bit BRGH (TXSTA<2>). Parity is not
supported by the hardware, but can be implemented in
software (and stored as the ninth data bit).
Asynchronous mode is stopped during SLEEP.
Asynchronous mode is selected by clearing bit SYNC
(TXSTA<4>).
The USART Asynchronous module consists of the
following important elements:
• Baud Rate Generator
• Sampling Circuit
• Asynchronous Transmitter
• Asynchronous Receiver
16.2.1 USART ASYNCHRONOUS
TRANSMITTER
The USART transmitter block diagram is shown in
Figure 16-1. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer, TXREG. The
TXREG register is loaded with data in software. The
TSR register is not loaded until the STOP bit has been
transmitted from the previous load. As soon as the
STOP bit is transmitted, the TSR is loaded with new
data from the TXREG register (if available). Once the
TXREG register transfers the data to the TSR register
(occurs in one TCY), the TXREG register is empty and
flag bit TXIF (PIR1<4>) is set. This interrupt can be
enabled/disabled by setting/clearing enable bit TXIE
( PIE1<4>). Flag bit TXIF will be set, regardless of the
state of enable bit TXIE and cannot be cleared in software.
It will reset only when new data is loaded into the
TXREG register. While flag bit TXIF indicated the status
of the TXREG register, another bit, TRMT
(TXSTA<1>), shows the status of the TSR register. Status
bit TRMT is a read-only bit, which is set when the
TSR register is empty. No interrupt logic is tied to this
bit, so the user has to poll this bit in order to determine
if the TSR register is empty.
To set up an asynchronous transmission:
1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 16.1).
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
5. Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Load data to the TXREG register (starts
transmission).
FIGURE 16-1: USART TRANSMIT BLOCK DIAGRAM
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit TXIF is set when enable bit TXEN
is set.
Note: TXIF is not cleared immediately upon loading
data into the transmit buffer TXREG.
The flag bit becomes valid in the second
instruction cycle following the load
instruction.
TXIF
TXIE
Interrupt
TXEN Baud Rate CLK
SPBRG
Baud Rate Generator
TX9D
MSb LSb
Data Bus
TXREG Register
TSR Register
(8) 0
TX9
TRMT SPEN
RC6/TX/CK pin
Pin Buffer
and Control
8
• • •© 2006 Microchip Technology Inc. DS39564C-page 173
PIC18FXX2
FIGURE 16-2: ASYNCHRONOUS TRANSMISSION
FIGURE 16-3: ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
TABLE 16-6: REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Word 1
STOP bit
Word 1
Transmit Shift Reg
START bit bit 0 bit 1 bit 7/8
Write to TXREG
Word 1
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Transmit Shift Reg.
Write to TXREG
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
TXIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1 Word 2
Word 1 Word 2
START bit STOP bit START bit
Transmit Shift Reg.
Word 1 Word 2
bit 0 bit 1 bit 7/8 bit 0
Note: This timing diagram shows two consecutive transmissions.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
TXREG USART Transmit Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented locations read as '0'.
Shaded cells are not used for Asynchronous Transmission.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.PIC18FXX2
DS39564C-page 174 © 2006 Microchip Technology Inc.
16.2.2 USART ASYNCHRONOUS
RECEIVER
The receiver block diagram is shown in Figure 16-4.
The data is received on the RC7/RX/DT pin and drives
the data recovery block. The data recovery block is
actually a high speed shifter operating at x16 times the
baud rate, whereas the main receive serial shifter operates
at the bit rate or at FOSC. This mode would
typically be used in RS-232 systems.
To set up an Asynchronous Reception:
1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 16.1).
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit RCIE.
4. If 9-bit reception is desired, set bit RX9.
5. Enable the reception by setting bit CREN.
6. Flag bit RCIF will be set when reception is complete
and an interrupt will be generated if enable
bit RCIE was set.
7. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
8. Read the 8-bit received data by reading the
RCREG register.
9. If any error occurred, clear the error by clearing
enable bit CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
16.2.3 SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is required,
set the BRGH bit.
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
3. If interrupts are required, set the RCEN bit and
select the desired priority level with the RCIP bit.
4. Set the RX9 bit to enable 9-bit reception.
5. Set the ADDEN bit to enable address detect.
6. Enable reception by setting the CREN bit.
7. The RCIF bit will be set when reception is complete.
The interrupt will be acknowledged if the
RCIE and GIE bits are set.
8. Read the RCSTA register to determine if any
error occurred during reception, as well as read
bit 9 of data (if applicable).
9. Read RCREG to determine if the device is being
addressed.
10. If any error occurred, clear the CREN bit.
11. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and interrupt the CPU.
FIGURE 16-4: USART RECEIVE BLOCK DIAGRAM
x64 Baud Rate CLK
SPBRG
Baud Rate Generator
RC7/RX/DT
Pin Buffer
and Control
SPEN
Data
Recovery
CREN OERR FERR
MSb RSR Register LSb
RX9D RCREG Register FIFO
Interrupt RCIF
RCIE
Data Bus
8
÷ 64
÷ 16
or
STOP (8) 7 1 0 START
RX9
• • •© 2006 Microchip Technology Inc. DS39564C-page 175
PIC18FXX2
FIGURE 16-5: ASYNCHRONOUS RECEPTION
TABLE 16-7: REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
START
bit bit0 bit1 bit7/8 bit0 STOP bit7/8
bit
START
bit
START
bit7/8 STOP bit
bit
RX (pin)
Reg
Rcv Buffer Reg
Rcv Shift
Read Rcv
Buffer Reg
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Word 1
RCREG
Word 2
RCREG
STOP
bit
Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word, causing
the OERR (overrun) bit to be set.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/GIEH PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
RCREG USART Receive Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented locations read as '0'.
Shaded cells are not used for Asynchronous Reception.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits
clear.PIC18FXX2
DS39564C-page 176 © 2006 Microchip Technology Inc.
16.3 USART Synchronous Master
Mode
In Synchronous Master mode, the data is transmitted in
a half-duplex manner (i.e., transmission and reception
do not occur at the same time). When transmitting data,
the reception is inhibited and vice versa. Synchronous
mode is entered by setting bit SYNC (TXSTA<4>). In
addition, enable bit SPEN (RCSTA<7>) is set in order
to configure the RC6/TX/CK and RC7/RX/DT I/O pins
to CK (clock) and DT (data) lines, respectively. The
Master mode indicates that the processor transmits the
master clock on the CK line. The Master mode is
entered by setting bit CSRC (TXSTA<7>).
16.3.1 USART SYNCHRONOUS MASTER
TRANSMISSION
The USART transmitter block diagram is shown in
Figure 16-1. The heart of the transmitter is the Transmit
(serial) Shift Register (TSR). The shift register obtains
its data from the read/write transmit buffer register
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available). Once the
TXREG register transfers the data to the TSR register
(occurs in one TCYCLE), the TXREG is empty and interrupt
bit TXIF (PIR1<4>) is set. The interrupt can be
enabled/disabled by setting/clearing enable bit TXIE
(PIE1<4>). Flag bit TXIF will be set, regardless of the
state of enable bit TXIE, and cannot be cleared in software.
It will reset only when new data is loaded into the
TXREG register. While flag bit TXIF indicates the status
of the TXREG register, another bit TRMT (TXSTA<1>)
shows the status of the TSR register. TRMT is a read
only bit, which is set when the TSR is empty. No interrupt
logic is tied to this bit, so the user has to poll this
bit in order to determine if the TSR register is empty.
The TSR is not mapped in data memory, so it is not
available to the user.
To set up a Synchronous Master Transmission:
1. Initialize the SPBRG register for the appropriate
baud rate (Section 16.1).
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN, and CSRC.
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set bit TX9.
5. Enable the transmission by setting bit TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Start transmission by loading data to the TXREG
register.
TABLE 16-8: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Note: TXIF is not cleared immediately upon loading
data into the transmit buffer TXREG.
The flag bit becomes valid in the second
instruction cycle following the load
instruction.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
TXREG USART Transmit Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'.
Shaded cells are not used for Synchronous Master Transmission.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits
clear.© 2006 Microchip Technology Inc. DS39564C-page 177
PIC18FXX2
FIGURE 16-6: SYNCHRONOUS TRANSMISSION
FIGURE 16-7: SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
bit 0 bit 1 bit 7
Word 1
Q1 Q2 Q3Q4 Q1 Q2Q3 Q4Q1 Q2Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3Q4 Q3Q4 Q1 Q2 Q3Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2Q3 Q4Q1 Q2Q3 Q4
RC7/RX/DT bit 2 bit 0 bit 1 bit 7
RC6/TX/CK
Write to
TXREG Reg
TXIF bit
(Interrupt Flag)
TRMT
TXEN bit
'1' '1'
Word 2
TRMT bit
Write Word1 Write Word2
Note: Sync Master mode; SPBRG = '0'. Continuous transmission of two 8-bit words.
pin
pin
RC7/RX/DT pin
RC6/TX/CK pin
Write to
TXREG reg
TXIF bit
TRMT bit
bit0 bit1 bit2 bit6 bit7
TXEN bitPIC18FXX2
DS39564C-page 178 © 2006 Microchip Technology Inc.
16.3.2 USART SYNCHRONOUS MASTER
RECEPTION
Once Synchronous mode is selected, reception is
enabled by setting either enable bit SREN
(RCSTA<5>), or enable bit CREN (RCSTA<4>). Data is
sampled on the RC7/RX/DT pin on the falling edge of
the clock. If enable bit SREN is set, only a single word
is received. If enable bit CREN is set, the reception is
continuous until CREN is cleared. If both bits are set,
then CREN takes precedence.
To set up a Synchronous Master Reception:
1. Initialize the SPBRG register for the appropriate
baud rate (Section 16.1).
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
3. Ensure bits CREN and SREN are clear.
4. If interrupts are desired, set enable bit RCIE.
5. If 9-bit reception is desired, set bit RX9.
6. If a single reception is required, set bit SREN.
For continuous reception, set bit CREN.
7. Interrupt flag bit RCIF will be set when reception
is complete and an interrupt will be generated if
the enable bit RCIE was set.
8. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 16-9: REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
FIGURE 16-8: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
RCREG USART Receive Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'. Shaded cells are not used for Synchronous Master Reception.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.
CREN bit
RC7/RX/DT pin
RC6/TX/CK pin
Write to
bit SREN
SREN bit
RCIF bit
(Interrupt)
Read
RXREG
Q2 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
'0'
bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7
'0'
Q1 Q2 Q3 Q4
Note: Timing diagram demonstrates Sync Master mode with bit SREN = '1' and bit BRGH = '0'.© 2006 Microchip Technology Inc. DS39564C-page 179
PIC18FXX2
16.4 USART Synchronous Slave Mode
Synchronous Slave mode differs from the Master mode
in the fact that the shift clock is supplied externally at
the RC6/TX/CK pin (instead of being supplied internally
in Master mode). This allows the device to transfer or
receive data while in SLEEP mode. Slave mode is
entered by clearing bit CSRC (TXSTA<7>).
16.4.1 USART SYNCHRONOUS SLAVE
TRANSMIT
The operation of the Synchronous Master and Slave
modes are identical, except in the case of the SLEEP
mode.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
a) The first word will immediately transfer to the
TSR register and transmit.
b) The second word will remain in TXREG register.
c) Flag bit TXIF will not be set.
d) When the first word has been shifted out of TSR,
the TXREG register will transfer the second
word to the TSR and flag bit TXIF will now be
set.
e) If enable bit TXIE is set, the interrupt will wake
the chip from SLEEP. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
To set up a Synchronous Slave Transmission:
1. Enable the synchronous slave serial port by setting
bits SYNC and SPEN and clearing bit
CSRC.
2. Clear bits CREN and SREN.
3. If interrupts are desired, set enable bit TXIE.
4. If 9-bit transmission is desired, set bit TX9.
5. Enable the transmission by setting enable bit
TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Start transmission by loading data to the TXREG
register.
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 16-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
TXREG USART Transmit Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'.
Shaded cells are not used for Synchronous Slave Transmission.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits
clear.PIC18FXX2
DS39564C-page 180 © 2006 Microchip Technology Inc.
16.4.2 USART SYNCHRONOUS SLAVE
RECEPTION
The operation of the Synchronous Master and Slave
modes is identical, except in the case of the SLEEP
mode and bit SREN, which is a “don't care” in Slave
mode.
If receive is enabled by setting bit CREN prior to the
SLEEP instruction, then a word may be received during
SLEEP. On completely receiving the word, the RSR
register will transfer the data to the RCREG register,
and if enable bit RCIE bit is set, the interrupt generated
will wake the chip from SLEEP. If the global interrupt is
enabled, the program will branch to the interrupt vector.
To set up a Synchronous Slave Reception:
1. Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
2. If interrupts are desired, set enable bit RCIE.
3. If 9-bit reception is desired, set bit RX9.
4. To enable reception, set enable bit CREN.
5. Flag bit RCIF will be set when reception is complete.
An interrupt will be generated if enable bit
RCIE was set.
6. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
7. Read the 8-bit received data by reading the
RCREG register.
8. If any error occurred, clear the error by clearing
bit CREN.
9. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 16-11: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 -00x 0000 -00x
RCREG USART Receive Register 0000 0000 0000 0000
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010 0000 -010
SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented, read as '0'.
Shaded cells are not used for Synchronous Slave Reception.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits
clear.© 2006 Microchip Technology Inc. DS39564C-page 181
PIC18FXX2
17.0 COMPATIBLE 10-BIT
ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The Analog-to-Digital (A/D) converter module has five
inputs for the PIC18F2X2 devices and eight for the
PIC18F4X2 devices. This module has the ADCON0
and ADCON1 register definitions that are compatible
with the mid-range A/D module.
The A/D allows conversion of an analog input signal to
a corresponding 10-bit digital number.
The A/D module has four registers. These registers
are:
• A/D Result High Register (ADRESH)
• A/D Result Low Register (ADRESL)
• A/D Control Register 0 (ADCON0)
• A/D Control Register 1 (ADCON1)
The ADCON0 register, shown in Register 17-1, controls
the operation of the A/D module. The ADCON1
register, shown in Register 17-2, configures the
functions of the port pins.
REGISTER 17-1: ADCON0 REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0
ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE — ADON
bit 7 bit 0
bit 7-6 ADCS1:ADCS0: A/D Conversion Clock Select bits (ADCON0 bits in bold)
bit 5-3 CHS2:CHS0: Analog Channel Select bits
000 = channel 0, (AN0)
001 = channel 1, (AN1)
010 = channel 2, (AN2)
011 = channel 3, (AN3)
100 = channel 4, (AN4)
101 = channel 5, (AN5)
110 = channel 6, (AN6)
111 = channel 7, (AN7)
Note: The PIC18F2X2 devices do not implement the full 8 A/D channels; the unimplemented
selections are reserved. Do not select any unimplemented channel.
bit 2 GO/DONE: A/D Conversion Status bit
When ADON = 1:
1 = A/D conversion in progress (setting this bit starts the A/D conversion which is automatically
cleared by hardware when the A/D conversion is complete)
0 = A/D conversion not in progress
bit 1 Unimplemented: Read as '0'
bit 0 ADON: A/D On bit
1 = A/D converter module is powered up
0 = A/D converter module is shut-off and consumes no operating current
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown
ADCON1
ADCON0
Clock Conversion
0 00 FOSC/2
0 01 FOSC/8
0 10 FOSC/32
0 11 FRC (clock derived from the internal A/D RC oscillator)
1 00 FOSC/4
1 01 FOSC/16
1 10 FOSC/64
1 11 FRC (clock derived from the internal A/D RC oscillator)PIC18FXX2
DS39564C-page 182 © 2006 Microchip Technology Inc.
REGISTER 17-2: ADCON1 REGISTER
R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0
ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0
bit 7 bit 0
bit 7 ADFM: A/D Result Format Select bit
1 = Right justified. Six (6) Most Significant bits of ADRESH are read as ’0’.
0 = Left justified. Six (6) Least Significant bits of ADRESL are read as ’0’.
bit 6 ADCS2: A/D Conversion Clock Select bit (ADCON1 bits in bold)
bit 5-4 Unimplemented: Read as '0'
bit 3-0 PCFG3:PCFG0: A/D Port Configuration Control bits
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown
Note: On any device RESET, the port pins that are multiplexed with analog functions (ANx) are
forced to be an analog input.
ADCON1
ADCON0
Clock Conversion
0 00 FOSC/2
0 01 FOSC/8
0 10 FOSC/32
0 11 FRC (clock derived from the internal A/D RC oscillator)
1 00 FOSC/4
1 01 FOSC/16
1 10 FOSC/64
1 11 FRC (clock derived from the internal A/D RC oscillator)
A = Analog input D = Digital I/O
C/R = # of analog input channels / # of A/D voltage references
PCFG
<3:0> AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0 VREF+ VREF- C / R
0000 A AAA A A AAVDD VSS 8 / 0
0001 A A A AVREF+ A A A AN3 VSS 7 / 1
0010 DDDA A A AAVDD VSS 5 / 0
0011 D D D AVREF+ A A A AN3 VSS 4 / 1
0100 DDDD A D AAVDD VSS 3 / 0
0101 D D D DVREF+ D A A AN3 VSS 2 / 1
011x D D D D D D D D — — 0 / 0
1000 A A A AVREF+ VREF- A A AN3 AN2 6 / 2
1001 DDAA A A AAVDD VSS 6 / 0
1010 D D A AVREF+ A A A AN3 VSS 5 / 1
1011 D D A AVREF+ VREF- A A AN3 AN2 4 / 2
1100 D D D AVREF+ VREF- A A AN3 AN2 3 / 2
1101 D D D DVREF+ VREF- A A AN3 AN2 2 / 2
1110 DDDD D D DAVDD VSS 1 / 0
1111 D D D DVREF+ VREF- D A AN3 AN2 1 / 2© 2006 Microchip Technology Inc. DS39564C-page 183
PIC18FXX2
The analog reference voltage is software selectable to
either the device’s positive and negative supply voltage
(VDD and VSS), or the voltage level on the RA3/AN3/
VREF+ pin and RA2/AN2/VREF- pin.
The A/D converter has a unique feature of being able
to operate while the device is in SLEEP mode. To operate
in SLEEP, the A/D conversion clock must be
derived from the A/D’s internal RC oscillator.
The output of the sample and hold is the input into the
converter, which generates the result via successive
approximation.
A device RESET forces all registers to their RESET
state. This forces the A/D module to be turned off and
any conversion is aborted.
Each port pin associated with the A/D converter can be
configured as an analog input (RA3 can also be a
voltage reference) or as a digital I/O.
The ADRESH and ADRESL registers contain the result
of the A/D conversion. When the A/D conversion is
complete, the result is loaded into the ADRESH/
ADRESL registers, the GO/DONE bit (ADCON0<2>) is
cleared, and A/D interrupt flag bit, ADIF is set. The block
diagram of the A/D module is shown in Figure 17-1.
FIGURE 17-1: A/D BLOCK DIAGRAM
(Input Voltage)
VAIN
VREF+
Reference
Voltage
VDD
PCFG<3:0>
CHS<2:0>
AN7*
AN6*
AN5*
AN4
AN3
AN2
AN1
AN0
111
110
101
100
011
010
001
000
10-bit
Converter
VREFVSS
A/D
* These channels are implemented only on the PIC18F4X2 devices.PIC18FXX2
DS39564C-page 184 © 2006 Microchip Technology Inc.
The value that is in the ADRESH/ADRESL registers is
not modified for a Power-on Reset. The ADRESH/
ADRESL registers will contain unknown data after a
Power-on Reset.
After the A/D module has been configured as desired,
the selected channel must be acquired before the conversion
is started. The analog input channels must
have their corresponding TRIS bits selected as an
input. To determine acquisition time, see Section 17.1.
After this acquisition time has elapsed, the A/D conversion
can be started. The following steps should be
followed for doing an A/D conversion:
1. Configure the A/D module:
• Configure analog pins, voltage reference and
digital I/O (ADCON1)
• Select A/D input channel (ADCON0)
• Select A/D conversion clock (ADCON0)
• Turn on A/D module (ADCON0)
2. Configure A/D interrupt (if desired):
• Clear ADIF bit
• Set ADIE bit
• Set GIE bit
• Set PEIE bit
3. Wait the required acquisition time.
4. Start conversion:
• Set GO/DONE bit (ADCON0)
5. Wait for A/D conversion to complete, by either:
• Polling for the GO/DONE bit to be cleared
(interrupts disabled)
OR
• Waiting for the A/D interrupt
6. Read A/D Result registers (ADRESH/ADRESL);
clear bit ADIF if required.
7. For next conversion, go to step 1 or step 2 as
required. The A/D conversion time per bit is
defined as TAD. A minimum wait of 2 TAD is
required before the next acquisition starts.
17.1 A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 17-2. The
source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
(VDD). The source impedance affects the offset voltage
at the analog input (due to pin leakage current). The
maximum recommended impedance for analog
sources is 2.5 kΩ. After the analog input channel is
selected (changed), this acquisition must be done
before the conversion can be started.
FIGURE 17-2: ANALOG INPUT MODEL
Note: When the conversion is started, the holding
capacitor is disconnected from the
input pin.
VAIN CPIN
Rs ANx
5 pF
VDD
VT = 0.6V
VT = 0.6V I LEAKAGE
RIC ≤ 1k
Sampling
Switch
SS RSS
CHOLD = 120 pF
VSS
6V
Sampling Switch
5V
4V
3V
2V
5 6 7 8 9 10 11
(kΩ)
VDD
± 500 nA
Legend: CPIN
VT
I LEAKAGE
RIC
SS
CHOLD
= input capacitance
= threshold voltage
= leakage current at the pin due to
= interconnect resistance
= sampling switch
= sample/hold capacitance (from DAC)
various junctions© 2006 Microchip Technology Inc. DS39564C-page 185
PIC18FXX2
To calculate the minimum acquisition time,
Equation 17-1 may be used. This equation assumes
that 1/2 LSb error is used (1024 steps for the A/D). The
1/2 LSb error is the maximum error allowed for the A/D
to meet its specified resolution.
EQUATION 17-1: ACQUISITION TIME
EQUATION 17-2: A/D MINIMUM CHARGING TIME
Example 17-1 shows the calculation of the minimum
required acquisition time, TACQ. This calculation is
based on the following application system assumptions:
• CHOLD = 120 pF
• Rs = 2.5 kΩ
• Conversion Error ≤ 1/2 LSb
• VDD = 5V → Rss = 7 kΩ
• Temperature = 50°C (system max.)
• VHOLD = 0V @ time = 0
EXAMPLE 17-1: CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
TACQ = Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
= TAMP + TC + TCOFF
VHOLD = (VREF – (VREF/2048)) • (1 – e(-Tc/CHOLD(RIC + RSS + RS)))
or
TC = -(120 pF)(1 kΩ + RSS + RS) ln(1/2048)
TACQ = TAMP + TC + TCOFF
Temperature coefficient is only required for temperatures > 25°C.
TACQ = 2 μs + TC + [(Temp – 25°C)(0.05 μs/°C)]
TC = -CHOLD (RIC + RSS + RS) ln(1/2048)
-120 pF (1 kΩ + 7 kΩ + 2.5 kΩ) ln(0.0004883)
-120 pF (10.5 kΩ) ln(0.0004883)
-1.26 μs (-7.6246)
9.61 μs
TACQ = 2 μs + 9.61 μs + [(50°C – 25°C)(0.05 μs/°C)]
11.61 μs + 1.25 μs
12.86 μsPIC18FXX2
DS39564C-page 186 © 2006 Microchip Technology Inc.
17.2 Selecting the A/D Conversion Clock
The A/D conversion time per bit is defined as TAD. The
A/D conversion requires 12 TAD per 10-bit conversion.
The source of the A/D conversion clock is software
selectable. The seven possible options for TAD are:
• 2 TOSC
• 4 TOSC
• 8 TOSC
• 16 TOSC
• 32 TOSC
• 64 TOSC
• Internal A/D module RC oscillator (2-6 μs)
For correct A/D conversions, the A/D conversion clock
(TAD) must be selected to ensure a minimum TAD time
of 1.6 μs.
Table 17-1 shows the resultant TAD times derived from
the device operating frequencies and the A/D clock
source selected.
17.3 Configuring Analog Port Pins
The ADCON1, TRISA and TRISE registers control the
operation of the A/D port pins. The port pins that are
desired as analog inputs, must have their corresponding
TRIS bits set (input). If the TRIS bit is cleared (output),
the digital output level (VOH or VOL) will be converted.
The A/D operation is independent of the state of the
CHS2:CHS0 bits and the TRIS bits.
TABLE 17-1: TAD vs. DEVICE OPERATING FREQUENCIES
Note 1: When reading the port register, all pins configured
as analog input channels will read
as cleared (a low level). Pins configured as
digital inputs will convert an analog input.
Analog levels on a digitally configured input
will not affect the conversion accuracy.
2: Analog levels on any pin that is defined as
a digital input (including the AN4:AN0
pins) may cause the input buffer to consume
current that is out of the device’s
specification.
AD Clock Source (TAD) Maximum Device Frequency
Operation ADCS2:ADCS0 PIC18FXX2 PIC18LFXX2
2 TOSC 000 1.25 MHz 666 kHz
4 TOSC 100 2.50 MHz 1.33 MHz
8 TOSC 001 5.00 MHz 2.67 MHz
16 TOSC 101 10.00 MHz 5.33 MHz
32 TOSC 010 20.00 MHz 10.67 MHz
64 TOSC 110 40.00 MHz 21.33 MHz
RC 011 — —© 2006 Microchip Technology Inc. DS39564C-page 187
PIC18FXX2
17.4 A/D Conversions
Figure 17-3 shows the operation of the A/D converter
after the GO bit has been set. Clearing the GO/DONE
bit during a conversion will abort the current conversion.
The A/D result register pair will NOT be updated
with the partially completed A/D conversion sample.
That is, the ADRESH:ADRESL registers will continue
to contain the value of the last completed conversion
(or the last value written to the ADRESH:ADRESL registers).
After the A/D conversion is aborted, a 2 TAD wait
is required before the next acquisition is started. After
this 2 TAD wait, acquisition on the selected channel is
automatically started. The GO/DONE bit can then be
set to start the conversion.
FIGURE 17-3: A/D CONVERSION TAD CYCLES
17.4.1 A/D RESULT REGISTERS
The ADRESH:ADRESL register pair is the location
where the 10-bit A/D result is loaded at the completion
of the A/D conversion. This register pair is 16-bits wide.
The A/D module gives the flexibility to left or right justify
the 10-bit result in the 16-bit result register. The A/D
Format Select bit (ADFM) controls this justification.
Figure 17-4 shows the operation of the A/D result justification.
The extra bits are loaded with ’0’s. When an
A/D result will not overwrite these locations (A/D
disable), these registers may be used as two general
purpose 8-bit registers.
FIGURE 17-4: A/D RESULT JUSTIFICATION
Note: The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD11
Set GO bit
Holding capacitor is disconnected from analog input (typically 100 ns)
b9 b8 b7 b6 b5 b4 b3 b2
TAD9 TAD10
b1 b0
TCY - TAD
Next Q4: ADRESH/ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
Conversion Starts
b0
10-bit Result
ADRESH ADRESL
0000 00
ADFM = 0
7 2 1 0 7 0
10-bit Result
ADRESH ADRESL
10-bit Result
0000 00
7 0 7 6 5 0
ADFM = 1
Right Justified Left JustifiedPIC18FXX2
DS39564C-page 188 © 2006 Microchip Technology Inc.
17.5 Use of the CCP2 Trigger
An A/D conversion can be started by the “special event
trigger” of the CCP2 module. This requires that the
CCP2M3:CCP2M0 bits (CCP2CON<3:0>) be programmed
as 1011 and that the A/D module is enabled
(ADON bit is set). When the trigger occurs, the GO/
DONE bit will be set, starting the A/D conversion, and
the Timer1 (or Timer3) counter will be reset to zero.
Timer1 (or Timer3) is reset to automatically repeat the
A/D acquisition period with minimal software overhead
(moving ADRESH/ADRESL to the desired location).
The appropriate analog input channel must be selected
and the minimum acquisition done before the “special
event trigger” sets the GO/DONE bit (starts a
conversion).
If the A/D module is not enabled (ADON is cleared), the
“special event trigger” will be ignored by the A/D
module, but will still reset the Timer1 (or Timer3)
counter.
TABLE 17-2: SUMMARY OF A/D REGISTERS
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on
POR, BOR
Value on
All Other
RESETS
INTCON GIE/
GIEH
PEIE/
GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1 PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
PIE1 PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
IPR1 PSPIP(1) ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 0000 0000 0000 0000
PIR2 — — — EEIF BCLIF LVDIF TMR3IF CCP2IF ---0 0000 ---0 0000
PIE2 — — — EEIE BCLIE LVDIE TMR3IE CCP2IE ---0 0000 ---0 0000
IPR2 — — — EEIP BCLIP LVDIP TMR3IP CCP2IP ---1 1111 ---1 0000
ADRESH A/D Result Register xxxx xxxx uuuu uuuu
ADRESL A/D Result Register xxxx xxxx uuuu uuuu
ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE — ADON 0000 00-0 0000 00-0
ADCON1 ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0 ---- -000 ---- -000
PORTA — RA6 RA5 RA4 RA3 RA2 RA1 RA0 --0x 0000 --0u 0000
TRISA — PORTA Data Direction Register --11 1111 --11 1111
PORTE — — — — — RE2 RE1 RE0 ---- -000 ---- -000
LATE — — — — — LATE2 LATE1 LATE0 ---- -xxx ---- -uuu
TRISE IBF OBF IBOV PSPMODE — PORTE Data Direction bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used for A/D conversion.
Note 1: The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X2 devices; always maintain these bits clear.© 2006 Microchip Technology Inc. DS39564C-page 189
PIC18FXX2
18.0 LOW VOLTAGE DETECT
In many applications, the ability to determine if the
device voltage (VDD) is below a specified voltage level
is a desirable feature. A window of operation for the
application can be created, where the application software
can do “housekeeping tasks” before the device
voltage exits the valid operating range. This can be
done using the Low Voltage Detect module.
This module is a software programmable circuitry,
where a device voltage trip point can be specified.
When the voltage of the device becomes lower then the
specified point, an interrupt flag is set. If the interrupt is
enabled, the program execution will branch to the interrupt
vector address and the software can then respond
to that interrupt source.
The Low Voltage Detect circuitry is completely under
software control. This allows the circuitry to be “turned
off” by the software, which minimizes the current
consumption for the device.
Figure 18-1 shows a possible application voltage curve
(typically for batteries). Over time, the device voltage
decreases. When the device voltage equals voltage VA,
the LVD logic generates an interrupt. This occurs at
time TA. The application software then has the time,
until the device voltage is no longer in valid operating
range, to shutdown the system. Voltage point VB is the
minimum valid operating voltage specification. This
occurs at time TB. The difference TB - TA is the total
time for shutdown.
FIGURE 18-1: TYPICAL LOW VOLTAGE DETECT APPLICATION
The block diagram for the LVD module is shown in
Figure 18-2. A comparator uses an internally generated
reference voltage as the set point. When the
selected tap output of the device voltage crosses the
set point (is lower than), the LVDIF bit is set.
Each node in the resistor divider represents a “trip
point” voltage. The “trip point” voltage is the minimum
supply voltage level at which the device can operate
before the LVD module asserts an interrupt. When the
supply voltage is equal to the trip point, the voltage
tapped off of the resistor array is equal to the 1.2V
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal setting the LVDIF bit. This voltage is
software programmable to any one of 16 values (see
Figure 18-2). The trip point is selected by
programming the LVDL3:LVDL0 bits (LVDCON<3:0>).
Time
Voltage
VA
VB
TA TB
VA = LVD trip point
VB = Minimum valid device
operating voltage
Legend:PIC18FXX2
DS39564C-page 190 © 2006 Microchip Technology Inc.
FIGURE 18-2: LOW VOLTAGE DETECT (LVD) BLOCK DIAGRAM
The LVD module has an additional feature that allows
the user to supply the trip voltage to the module from
an external source. This mode is enabled when bits
LVDL3:LVDL0 are set to 1111. In this state, the comparator
input is multiplexed from the external input pin,
LVDIN (Figure 18-3). This gives users flexibility,
because it allows them to configure the Low Voltage
Detect interrupt to occur at any voltage in the valid
operating range.
FIGURE 18-3: LOW VOLTAGE DETECT (LVD) WITH EXTERNAL INPUT BLOCK DIAGRAM
LVDIF
VDD
16 to 1 MUX
LVDEN
LVD Control
Register
Internally Generated
Reference Voltage
LVDIN
1.2V Typical
–
+
LVD
EN
LVD Control
16 to 1 MUX
BGAP
BODEN
LVDEN
VxEN
LVDIN
Register
VDD
VDD
Externally Generated
Trip Point –
+© 2006 Microchip Technology Inc. DS39564C-page 191
PIC18FXX2
18.1 Control Register
The Low Voltage Detect Control register controls the
operation of the Low Voltage Detect circuitry.
REGISTER 18-1: LVDCON REGISTER
U-0 U-0 R-0 R/W-0 R/W-0 R/W-1 R/W-0 R/W-1
— — IRVST LVDEN LVDL3 LVDL2 LVDL1 LVDL0
bit 7 bit 0
bit 7-6 Unimplemented: Read as '0'
bit 5 IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the Low Voltage Detect logic will generate the interrupt flag at the
specified voltage range
0 = Indicates that the Low Voltage Detect logic will not generate the interrupt flag at the
specified voltage range and the LVD interrupt should not be enabled
bit 4 LVDEN: Low Voltage Detect Power Enable bit
1 = Enables LVD, powers up LVD circuit
0 = Disables LVD, powers down LVD circuit
bit 3-0 LVDL3:LVDL0: Low Voltage Detection Limit bits
1111 = External analog input is used (input comes from the LVDIN pin)
1110 = 4.5V - 4.77V
1101 = 4.2V - 4.45V
1100 = 4.0V - 4.24V
1011 = 3.8V - 4.03V
1010 = 3.6V - 3.82V
1001 = 3.5V - 3.71V
1000 = 3.3V - 3.50V
0111 = 3.0V - 3.18V
0110 = 2.8V - 2.97V
0101 = 2.7V - 2.86V
0100 = 2.5V - 2.65V
0011 = 2.4V - 2.54V
0010 = 2.2V - 2.33V
0001 = 2.0V - 2.12V
0000 = Reserved
Note: LVDL3:LVDL0 modes which result in a trip point below the valid operating voltage
of the device are not tested.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknownPIC18FXX2
DS39564C-page 192 © 2006 Microchip Technology Inc.
18.2 Operation
Depending on the power source for the device voltage,
the voltage normally decreases relatively slowly. This
means that the LVD module does not need to be constantly
operating. To decrease the current requirements,
the LVD circuitry only needs to be enabled for
short periods, where the voltage is checked. After
doing the check, the LVD module may be disabled.
Each time that the LVD module is enabled, the circuitry
requires some time to stabilize. After the circuitry has
stabilized, all status flags may be cleared. The module
will then indicate the proper state of the system.
The following steps are needed to set up the LVD
module:
1. Write the value to the LVDL3:LVDL0 bits
(LVDCON register), which selects the desired
LVD Trip Point.
2. Ensure that LVD interrupts are disabled (the
LVDIE bit is cleared or the GIE bit is cleared).
3. Enable the LVD module (set the LVDEN bit in
the LVDCON register).
4. Wait for the LVD module to stabilize (the IRVST
bit to become set).
5. Clear the LVD interrupt flag, which may have
falsely become set until the LVD module has
stabilized (clear the LVDIF bit).
6. Enable the LVD interrupt (set the LVDIE and the
GIE bits).
Figure 18-4 shows typical waveforms that the LVD
module may be used to detect.
FIGURE 18-4: LOW VOLTAGE DETECT WAVEFORMS
VLVD
VDD
LVDIF
VLVD
VDD
Enable LVD
Internally Generated TIVRST
LVDIF may not be set
Enable LVD
LVDIF
LVDIF cleared in software
LVDIF cleared in software
LVDIF cleared in software,
CASE 1:
CASE 2:
LVDIF remains set since LVD condition still exists
Reference Stable
Internally Generated
Reference Stable
TIVRST© 2006 Microchip Technology Inc. DS39564C-page 193
PIC18FXX2
18.2.1 REFERENCE VOLTAGE SET POINT
The Internal Reference Voltage of the LVD module may
be used by other internal circuitry (the Programmable
Brown-out Reset). If these circuits are disabled (lower
current consumption), the reference voltage circuit
requires a time to become stable before a low voltage
condition can be reliably detected. This time is invariant
of system clock speed. This start-up time is specified in
electrical specification parameter 36. The low voltage
interrupt flag will not be enabled until a stable reference
voltage is reached. Refer to the waveform in Figure 18-4.
18.2.2 CURRENT CONSUMPTION
When the module is enabled, the LVD comparator and
voltage divider are enabled and will consume static current.
The voltage divider can be tapped from multiple
places in the resistor array. Total current consumption,
when enabled, is specified in electrical specification
parameter #D022B.
18.3 Operation During SLEEP
When enabled, the LVD circuitry continues to operate
during SLEEP. If the device voltage crosses the trip
point, the LVDIF bit will be set and the device will wakeup
from SLEEP. Device execution will continue from
the interrupt vector address if interrupts have been
globally enabled.
18.4 Effects of a RESET
A device RESET forces all registers to their RESET
state. This forces the LVD module to be turned off. PIC18FXX2
DS39564C-page 194 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 195
PIC18FXX2
19.0 SPECIAL FEATURES OF THE
CPU
There are several features intended to maximize system
reliability, minimize cost through elimination of
external components, provide power saving Operating
modes and offer code protection. These are:
• OSC Selection
• RESET
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code Protection
• ID Locations
• In-Circuit Serial Programming
All PIC18FXX2 devices have a Watchdog Timer, which
is permanently enabled via the configuration bits or
software controlled. It runs off its own RC oscillator for
added reliability. There are two timers that offer necessary
delays on power-up. One is the Oscillator Start-up
Timer (OST), intended to keep the chip in RESET until
the crystal oscillator is stable. The other is the Powerup
Timer (PWRT), which provides a fixed delay on
power-up only, designed to keep the part in RESET
while the power supply stabilizes. With these two timers
on-chip, most applications need no external
RESET circuitry.
SLEEP mode is designed to offer a very low current
Power-down mode. The user can wake-up from
SLEEP through external RESET, Watchdog Timer
Wake-up or through an interrupt. Several oscillator
options are also made available to allow the part to fit
the application. The RC oscillator option saves system
cost, while the LP crystal option saves power. A set of
configuration bits are used to select various options.
19.1 Configuration Bits
The configuration bits can be programmed (read as '0'),
or left unprogrammed (read as '1'), to select various
device configurations. These bits are mapped starting
at program memory location 300000h.
The user will note that address 300000h is beyond the
user program memory space. In fact, it belongs to the
configuration memory space (300000h - 3FFFFFh),
which can only be accessed using Table Reads and
Table Writes.
Programming the configuration registers is done in a
manner similar to programming the FLASH memory
(see Section 5.5.1). The only difference is the configuration
registers are written a byte at a time. The
sequence of events for programming configuration
registers is:
1. Load table pointer with address of configuration
register being written.
2. Write a single byte using the TBLWT instruction.
3. Set EEPGD to point to program memory, set the
CFGS bit to access configuration registers, and
set WREN to enable byte writes.
4. Disable interrupts.
5. Write 55h to EECON2.
6. Write AAh to EECON2.
7. Set the WR bit. This will begin the write cycle.
8. CPU will stall for duration of write (approximately
2 ms using internal timer).
9. Execute a NOP.
10. Re-enable interrupts.PIC18FXX2
DS39564C-page 196 © 2006 Microchip Technology Inc.
TABLE 19-1: CONFIGURATION BITS AND DEVICE IDS
REGISTER 19-1: CONFIGURATION REGISTER 1 HIGH (CONFIG1H: BYTE ADDRESS 300001h)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Default/
Unprogrammed
Value
300001h CONFIG1H — — OSCSEN — — FOSC2 FOSC1 FOSC0 --1- -111
300002h CONFIG2L — — — — BORV1 BORV0 BOREN PWRTEN ---- 1111
300003h CONFIG2H — — — — WDTPS2 WDTPS1 WDTPS0 WDTEN ---- 1111
300005h CONFIG3H — — — — — — — CCP2MX ---- ---1
300006h CONFIG4L DEBUG — — — — LVP — STVREN 1--- -1-1
300008h CONFIG5L — — — — CP3 CP2 CP1 CP0 ---- 1111
300009h CONFIG5H CPD CPB — — — — — — 11-- ----
30000Ah CONFIG6L — — — — WRT3 WRT2 WRT1 WRT0 ---- 1111
30000Bh CONFIG6H WRTD WRTB WRTC — — — — — 111- ----
30000Ch CONFIG7L — — — — EBTR3 EBTR2 EBTR1 EBTR0 ---- 1111
30000Dh CONFIG7H — EBTRB — — — — — — -1-- ----
3FFFFEh DEVID1 DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0 (1)
3FFFFFh DEVID2 DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3 0000 0100
Legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition.
Shaded cells are unimplemented, read as ‘0’.
Note 1: See Register 19-12 for DEVID1 values.
U-0 U-0 R/P-1 U-0 U-0 R/P-1 R/P-1 R/P-1
— — OSCSEN — — FOSC2 FOSC1 FOSC0
bit 7 bit 0
bit 7-6 Unimplemented: Read as ‘0’
bit 5 OSCSEN: Oscillator System Clock Switch Enable bit
1 = Oscillator system clock switch option is disabled (main oscillator is source)
0 = Oscillator system clock switch option is enabled (oscillator switching is enabled)
bit 4-3 Unimplemented: Read as ‘0’
bit 2-0 FOSC2:FOSC0: Oscillator Selection bits
111 = RC oscillator w/ OSC2 configured as RA6
110 = HS oscillator with PLL enabled/Clock frequency = (4 x FOSC)
101 = EC oscillator w/ OSC2 configured as RA6
100 = EC oscillator w/ OSC2 configured as divide-by-4 clock output
011 = RC oscillator
010 = HS oscillator
001 = XT oscillator
000 = LP oscillator
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state© 2006 Microchip Technology Inc. DS39564C-page 197
PIC18FXX2
REGISTER 19-2: CONFIGURATION REGISTER 2 LOW (CONFIG2L: BYTE ADDRESS 300002h)
REGISTER 19-3: CONFIGURATION REGISTER 2 HIGH (CONFIG2H: BYTE ADDRESS 300003h)
U-0 U-0 U-0 U-0 R/P-1 R/P-1 R/P-1 R/P-1
— — — — BORV1 BORV0 BOREN PWRTEN
bit 7 bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3-2 BORV1:BORV0: Brown-out Reset Voltage bits
11 = VBOR set to 2.5V
10 = VBOR set to 2.7V
01 = VBOR set to 4.2V
00 = VBOR set to 4.5V
bit 1 BOREN: Brown-out Reset Enable bit
1 = Brown-out Reset enabled
0 = Brown-out Reset disabled
bit 0 PWRTEN: Power-up Timer Enable bit
1 = PWRT disabled
0 = PWRT enabled
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
U-0 U-0 U-0 U-0 R/P-1 R/P-1 R/P-1 R/P-1
— — — — WDTPS2 WDTPS1 WDTPS0 WDTEN
bit 7 bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3-1 WDTPS2:WDTPS0: Watchdog Timer Postscale Select bits
111 = 1:128
110 = 1:64
101 = 1:32
100 = 1:16
011 = 1:8
010 = 1:4
001 = 1:2
000 = 1:1
bit 0 WDTEN: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled (control is placed on the SWDTEN bit)
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed statePIC18FXX2
DS39564C-page 198 © 2006 Microchip Technology Inc.
REGISTER 19-4: CONFIGURATION REGISTER 3 HIGH (CONFIG3H: BYTE ADDRESS 300005h)
REGISTER 19-5: CONFIGURATION REGISTER 4 LOW (CONFIG4L: BYTE ADDRESS 300006h)
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/P-1
— — — — — — — CCP2MX
bit 7 bit 0
bit 7-1 Unimplemented: Read as ‘0’
bit 0 CCP2MX: CCP2 Mux bit
1 = CCP2 input/output is multiplexed with RC1
0 = CCP2 input/output is multiplexed with RB3
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
R/P-1 U-0 U-0 U-0 U-0 R/P-1 U-0 R/P-1
BKBUG — — — — LVP — STVREN
bit 7 bit 0
bit 7 DEBUG: Background Debugger Enable bit
1 = Background Debugger disabled. RB6 and RB7 configured as general purpose I/O pins.
0 = Background Debugger enabled. RB6 and RB7 are dedicated to In-Circuit Debug.
bit 6-3 Unimplemented: Read as ‘0’
bit 2 LVP: Low Voltage ICSP Enable bit
1 = Low Voltage ICSP enabled
0 = Low Voltage ICSP disabled
bit 1 Unimplemented: Read as ‘0’
bit 0 STVREN: Stack Full/Underflow Reset Enable bit
1 = Stack Full/Underflow will cause RESET
0 = Stack Full/Underflow will not cause RESET
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state© 2006 Microchip Technology Inc. DS39564C-page 199
PIC18FXX2
REGISTER 19-6: CONFIGURATION REGISTER 5 LOW (CONFIG5L: BYTE ADDRESS 300008h)
REGISTER 19-7: CONFIGURATION REGISTER 5 HIGH (CONFIG5H: BYTE ADDRESS 300009h)
U-0 U-0 U-0 U-0 R/C-1 R/C-1 R/C-1 R/C-1
— — — — CP3(1) CP2(1) CP1 CP0
bit 7 bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3 CP3: Code Protection bit(1)
1 = Block 3 (006000-007FFFh) not code protected
0 = Block 3 (006000-007FFFh) code protected
bit 2 CP2: Code Protection bit(1)
1 = Block 2 (004000-005FFFh) not code protected
0 = Block 2 (004000-005FFFh) code protected
bit 1 CP1: Code Protection bit
1 = Block 1 (002000-003FFFh) not code protected
0 = Block 1 (002000-003FFFh) code protected
bit 0 CP0: Code Protection bit
1 = Block 0 (000200-001FFFh) not code protected
0 = Block 0 (000200-001FFFh) code protected
Note 1: Unimplemented in PIC18FX42 devices; maintain this bit set.
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
R/C-1 R/C-1 U-0 U-0 U-0 U-0 U-0 U-0
CPD CPB — — — — — —
bit 7 bit 0
bit 7 CPD: Data EEPROM Code Protection bit
1 = Data EEPROM not code protected
0 = Data EEPROM code protected
bit 6 CPB: Boot Block Code Protection bit
1 = Boot Block (000000-0001FFh) not code protected
0 = Boot Block (000000-0001FFh) code protected
bit 5-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed statePIC18FXX2
DS39564C-page 200 © 2006 Microchip Technology Inc.
REGISTER 19-8: CONFIGURATION REGISTER 6 LOW (CONFIG6L: BYTE ADDRESS 30000Ah)
REGISTER 19-9: CONFIGURATION REGISTER 6 HIGH (CONFIG6H: BYTE ADDRESS 30000Bh)
U-0 U-0 U-0 U-0 R/C-1 R/C-1 R/C-1 R/C-1
— — — — WRT3(1) WRT2(1) WRT1 WRT0
bit 7 bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3 WRT3: Write Protection bit(1)
1 = Block 3 (006000-007FFFh) not write protected
0 = Block 3 (006000-007FFFh) write protected
bit 2 WRT2: Write Protection bit(1)
1 = Block 2 (004000-005FFFh) not write protected
0 = Block 2 (004000-005FFFh) write protected
bit 1 WRT1: Write Protection bit
1 = Block 1 (002000-003FFFh) not write protected
0 = Block 1 (002000-003FFFh) write protected
bit 0 WRT0: Write Protection bit
1 = Block 0 (000200h-001FFFh) not write protected
0 = Block 0 (000200h-001FFFh) write protected
Note 1: Unimplemented in PIC18FX42 devices; maintain this bit set.
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
R/C-1 R/C-1 C-1 U-0 U-0 U-0 U-0 U-0
WRTD WRTB WRTC — — — — —
bit 7 bit 0
bit 7 WRTD: Data EEPROM Write Protection bit
1 = Data EEPROM not write protected
0 = Data EEPROM write protected
bit 6 WRTB: Boot Block Write Protection bit
1 = Boot Block (000000-0001FFh) not write protected
0 = Boot Block (000000-0001FFh) write protected
bit 5 WRTC: Configuration Register Write Protection bit
1 = Configuration registers (300000-3000FFh) not write protected
0 = Configuration registers (300000-3000FFh) write protected
Note: This bit is read only, and cannot be changed in User mode.
bit 4-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit C =Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state© 2006 Microchip Technology Inc. DS39564C-page 201
PIC18FXX2
REGISTER 19-10: CONFIGURATION REGISTER 7 LOW (CONFIG7L: BYTE ADDRESS 30000Ch)
REGISTER 19-11: CONFIGURATION REGISTER 7 HIGH (CONFIG7H: BYTE ADDRESS 30000Dh)
U-0 U-0 U-0 U-0 R/C-1 R/C-1 R/C-1 R/C-1
— — — — EBTR3(1) EBTR2(1) EBTR1 EBTR0
bit 7 bit 0
bit 7-4 Unimplemented: Read as ‘0’
bit 3 EBTR3: Table Read Protection bit(1)
1 = Block 3 (006000-007FFFh) not protected from Table Reads executed in other blocks
0 = Block 3 (006000-007FFFh) protected from Table Reads executed in other blocks
bit 2 EBTR2: Table Read Protection bit(1)
1 = Block 2 (004000-005FFFh) not protected from Table Reads executed in other blocks
0 = Block 2 (004000-005FFFh) protected from Table Reads executed in other blocks
bit 1 EBTR1: Table Read Protection bit
1 = Block 1 (002000-003FFFh) not protected from Table Reads executed in other blocks
0 = Block 1 (002000-003FFFh) protected from Table Reads executed in other blocks
bit 0 EBTR0: Table Read Protection bit
1 = Block 0 (000200h-001FFFh) not protected from Table Reads executed in other blocks
0 = Block 0 (000200h-001FFFh) protected from Table Reads executed in other blocks
Note 1: Unimplemented in PIC18FX42 devices; maintain this bit set.
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
U-0 R/C-1 U-0 U-0 U-0 U-0 U-0 U-0
— EBTRB — — — — — —
bit 7 bit 0
bit 7 Unimplemented: Read as ‘0’
bit 6 EBTRB: Boot Block Table Read Protection bit
1 = Boot Block (000000-0001FFh) not protected from Table Reads executed in other blocks
0 = Boot Block (000000-0001FFh) protected from Table Reads executed in other blocks
bit 5-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit C =Clearable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed statePIC18FXX2
DS39564C-page 202 © 2006 Microchip Technology Inc.
REGISTER 19-12: DEVICE ID REGISTER 1 FOR PIC18FXX2 (DEVID1: BYTE ADDRESS 3FFFFEh)
REGISTER 19-13: DEVICE ID REGISTER 2 FOR PIC18FXX2 (DEVID2: BYTE ADDRESS 3FFFFFh)
RRRRRRRR
DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0
bit 7 bit 0
bit 7-5 DEV2:DEV0: Device ID bits
000 = PIC18F252
001 = PIC18F452
100 = PIC18F242
101 = PIC18F442
bit 4-0 REV4:REV0: Revision ID bits
These bits are used to indicate the device revision.
Legend:
R = Readable bit P =Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state
RRRRRRRR
DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3
bit 7 bit 0
bit 7-0 DEV10:DEV3: Device ID bits
These bits are used with the DEV2:DEV0 bits in the Device ID Register 1 to identify the
part number.
Legend:
R = Readable bit P =Programmable bit U = Unimplemented bit, read as ‘0’
- n = Value when device is unprogrammed u = Unchanged from programmed state© 2006 Microchip Technology Inc. DS39564C-page 203
PIC18FXX2
19.2 Watchdog Timer (WDT)
The Watchdog Timer is a free running on-chip RC oscillator,
which does not require any external components.
This RC oscillator is separate from the RC oscillator of
the OSC1/CLKI pin. That means that the WDT will run,
even if the clock on the OSC1/CLKI and OSC2/CLKO/
RA6 pins of the device has been stopped, for example,
by execution of a SLEEP instruction.
During normal operation, a WDT time-out generates a
device RESET (Watchdog Timer Reset). If the device is
in SLEEP mode, a WDT time-out causes the device to
wake-up and continue with normal operation (Watchdog
Timer Wake-up). The TO bit in the RCON register
will be cleared upon a WDT time-out.
The Watchdog Timer is enabled/disabled by a device
configuration bit. If the WDT is enabled, software execution
may not disable this function. When the WDTEN
configuration bit is cleared, the SWDTEN bit enables/
disables the operation of the WDT.
The WDT time-out period values may be found in the
Electrical Specifications (Section 22.0) under parameter
D031. Values for the WDT postscaler may be
assigned using the configuration bits.
19.2.1 CONTROL REGISTER
Register 19-14 shows the WDTCON register. This is a
readable and writable register, which contains a control
bit that allows software to override the WDT enable
configuration bit, only when the configuration bit has
disabled the WDT.
REGISTER 19-14: WDTCON REGISTER
Note: The CLRWDT and SLEEP instructions clear
the WDT and the postscaler, if assigned to
the WDT and prevent it from timing out and
generating a device RESET condition.
Note: When a CLRWDT instruction is executed
and the postscaler is assigned to the WDT,
the postscaler count will be cleared, but the
postscaler assignment is not changed.
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0
— — — — — — — SWDTEN
bit 7 bit 0
bit 7-1 Unimplemented: Read as ’0’
bit 0 SWDTEN: Software Controlled Watchdog Timer Enable bit
1 = Watchdog Timer is on
0 = Watchdog Timer is turned off if the WDTEN configuration bit in the configuration
register = ‘0’
Legend:
R = Readable bit W = Writable bit
U = Unimplemented bit, read as ‘0’ - n = Value at PORPIC18FXX2
DS39564C-page 204 © 2006 Microchip Technology Inc.
19.2.2 WDT POSTSCALER
The WDT has a postscaler that can extend the WDT
Reset period. The postscaler is selected at the time of
the device programming, by the value written to the
CONFIG2H configuration register.
FIGURE 19-1: WATCHDOG TIMER BLOCK DIAGRAM
TABLE 19-2: SUMMARY OF WATCHDOG TIMER REGISTERS
WDT Timer Postscaler
WDTEN
8 - to - 1 MUX WDTPS2:WDTPS0
WDT
Time-out
8
SWDTEN bit
Configuration bit
Note: WDPS2:WDPS0 are bits in register CONFIG2H.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
CONFIG2H — — — — WDTPS2 WDTPS2 WDTPS0 WDTEN
RCON IPEN — — RI TO PD POR BOR
WDTCON — — — — — — — SWDTEN
Legend: Shaded cells are not used by the Watchdog Timer.© 2006 Microchip Technology Inc. DS39564C-page 205
PIC18FXX2
19.3 Power-down Mode (SLEEP)
Power-down mode is entered by executing a SLEEP
instruction.
If enabled, the Watchdog Timer will be cleared, but
keeps running, the PD bit (RCON<3>) is cleared, the
TO (RCON<4>) bit is set, and the oscillator driver is
turned off. The I/O ports maintain the status they had
before the SLEEP instruction was executed (driving
high, low or hi-impedance).
For lowest current consumption in this mode, place all
I/O pins at either VDD or VSS, ensure no external circuitry
is drawing current from the I/O pin, power-down
the A/D and disable external clocks. Pull all I/O pins
that are hi-impedance inputs, high or low externally, to
avoid switching currents caused by floating inputs. The
T0CKI input should also be at VDD or VSS for lowest
current consumption. The contribution from on-chip
pull-ups on PORTB should be considered.
The MCLR pin must be at a logic high level (VIHMC).
19.3.1 WAKE-UP FROM SLEEP
The device can wake-up from SLEEP through one of
the following events:
1. External RESET input on MCLR pin.
2. Watchdog Timer Wake-up (if WDT was
enabled).
3. Interrupt from INT pin, RB port change or a
Peripheral Interrupt.
The following peripheral interrupts can wake the device
from SLEEP:
1. PSP read or write.
2. TMR1 interrupt. Timer1 must be operating as
an asynchronous counter.
3. TMR3 interrupt. Timer3 must be operating as
an asynchronous counter.
4. CCP Capture mode interrupt.
5. Special event trigger (Timer1 in Asynchronous
mode using an external clock).
6. MSSP (START/STOP) bit detect interrupt.
7. MSSP transmit or receive in Slave mode
(SPI/I2C).
8. USART RX or TX (Synchronous Slave mode).
9. A/D conversion (when A/D clock source is RC).
10. EEPROM write operation complete.
11. LVD interrupt.
Other peripherals cannot generate interrupts, since
during SLEEP, no on-chip clocks are present.
External MCLR Reset will cause a device RESET. All
other events are considered a continuation of program
execution and will cause a “wake-up”. The TO and PD
bits in the RCON register can be used to determine the
cause of the device RESET. The PD bit, which is set on
power-up, is cleared when SLEEP is invoked. The TO
bit is cleared, if a WDT time-out occurred (and caused
wake-up).
When the SLEEP instruction is being executed, the next
instruction (PC + 2) is pre-fetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up is
regardless of the state of the GIE bit. If the GIE bit is
clear (disabled), the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
set (enabled), the device executes the instruction after
the SLEEP instruction and then branches to the interrupt
address. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
19.3.2 WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If an interrupt condition (interrupt flag bit and interrupt
enable bits are set) occurs before the execution
of a SLEEP instruction, the SLEEP instruction
will complete as a NOP. Therefore, the WDT and
WDT postscaler will not be cleared, the TO bit will
not be set and PD bits will not be cleared.
• If the interrupt condition occurs during or after
the execution of a SLEEP instruction, the device
will immediately wake-up from SLEEP. The
SLEEP instruction will be completely executed
before the wake-up. Therefore, the WDT and
WDT postscaler will be cleared, the TO bit will be
set and the PD bit will be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT instruction
should be executed before a SLEEP instruction.PIC18FXX2
DS39564C-page 206 © 2006 Microchip Technology Inc.
FIGURE 19-2: WAKE-UP FROM SLEEP THROUGH INTERRUPT(1,2)
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKO(4)
INT pin
INTF flag
(INTCON<1>)
GIEH bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
PC PC+2 PC+4
Inst(PC) = SLEEP
Inst(PC - 1)
Inst(PC + 2)
SLEEP
Processor in
SLEEP
Interrupt Latency(3)
Inst(PC + 4)
Inst(PC + 2)
Inst(0008h) Inst(000Ah)
Dummy Cycle Inst(0008h)
PC + 4 0008h 000Ah
Dummy Cycle
TOST(2)
PC+4
Note 1: XT, HS or LP Oscillator mode assumed.
2: GIE = '1' assumed. In this case, after wake-up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line.
3: TOST = 1024 TOSC (drawing not to scale). This delay will not occur for RC and EC Osc modes.
4: CLKO is not available in these Osc modes, but shown here for timing reference.© 2006 Microchip Technology Inc. DS39564C-page 207
PIC18FXX2
19.4 Program Verification and
Code Protection
The overall structure of the code protection on the
PIC18 FLASH devices differs significantly from other
PICmicro devices.
The user program memory is divided into five blocks.
One of these is a boot block of 512 bytes. The remainder
of the memory is divided into four blocks on binary
boundaries.
Each of the five blocks has three code protection bits
associated with them. They are:
• Code Protect bit (CPn)
• Write Protect bit (WRTn)
• External Block Table Read bit (EBTRn)
Figure 19-3 shows the program memory organization
for 16- and 32-Kbyte devices, and the specific code
protection bit associated with each block. The actual
locations of the bits are summarized in Table 19-3.
FIGURE 19-3: CODE PROTECTED PROGRAM MEMORY FOR PIC18F2XX/4XX
TABLE 19-3: SUMMARY OF CODE PROTECTION REGISTERS
MEMORY SIZE/DEVICE
Block Code Protection
16 Kbytes Controlled By:
(PIC18FX42)
32 Kbytes
(PIC18FX52)
Address
Range
Boot Block Boot Block 000000h
0001FFh CPB, WRTB, EBTRB
Block 0 Block 0
000200h
001FFFh
CP0, WRT0, EBTR0
Block 1 Block 1
002000h
003FFFh
CP1, WRT1, EBTR1
Unimplemented
Read 0’s Block 2
004000h
005FFFh
CP2, WRT2, EBTR2
Unimplemented
Read 0’s Block 3
006000h
007FFFh
CP3, WRT3, EBTR3
Unimplemented
Read 0’s
Unimplemented
Read 0’s
008000h
1FFFFFh
(Unimplemented Memory Space)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
300008h CONFIG5L — — — — CP3 CP2 CP1 CP0
300009h CONFIG5H CPD CPB — — — — — —
30000Ah CONFIG6L — — — — WRT3 WRT2 WRT1 WRT0
30000Bh CONFIG6H WRTD WRTB WRTC — — — — —
30000Ch CONFIG7L — — — — EBTR3 EBTR2 EBTR1 EBTR0
30000Dh CONFIG7H — EBTRB — — — — — —
Legend: Shaded cells are unimplemented.PIC18FXX2
DS39564C-page 208 © 2006 Microchip Technology Inc.
19.4.1 PROGRAM MEMORY
CODE PROTECTION
The user memory may be read to or written from any
location using the Table Read and Table Write instructions.
The device ID may be read with Table Reads.
The configuration registers may be read and written
with the Table Read and Table Write instructions.
In User mode, the CPn bits have no direct effect. CPn
bits inhibit external reads and writes. A block of user
memory may be protected from Table Writes if the
WRTn configuration bit is ‘0’. The EBTRn bits control
Table Reads. For a block of user memory with the
EBTRn bit set to ‘0’, a Table Read instruction that
executes from within that block is allowed to read. A
Table Read instruction that executes from a location
outside of that block is not allowed to read, and will
result in reading ‘0’s. Figures 19-4 through 19-6
illustrate Table Write and Table Read protection.
FIGURE 19-4: TABLE WRITE (WRTn) DISALLOWED
Note: Code protection bits may only be written to
a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code protection
bits are only set to ‘1’ by a full chip
erase or block erase function. The full chip
erase and block erase functions can only
be initiated via ICSP or an external
programmer.
000000h
0001FFh
000200h
001FFFh
002000h
003FFFh
004000h
005FFFh
006000h
007FFFh
WRTB,EBTRB = 11
WRT0,EBTR0 = 01
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11
TBLWT *
TBLPTR = 000FFF
PC = 001FFE
PC = 004FFE TBLWT *
Register Values Program Memory Configuration Bit Settings
Results: All Table Writes disabled to Blockn whenever WRTn = ‘0’.© 2006 Microchip Technology Inc. DS39564C-page 209
PIC18FXX2
FIGURE 19-5: EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
FIGURE 19-6: EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
000000h
0001FFh
000200h
001FFFh
002000h
003FFFh
004000h
005FFFh
006000h
007FFFh
WRTB,EBTRB = 11
WRT0,EBTR0 = 10
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11
TBLRD *
TBLPTR = 000FFF
PC = 002FFE
Results: All Table Reads from external blocks to Blockn are disabled whenever EBTRn = ‘0’.
TABLAT register returns a value of “0”.
Register Values Program Memory Configuration Bit Settings
000000h
0001FFh
000200h
001FFFh
002000h
003FFFh
004000h
005FFFh
006000h
007FFFh
WRTB,EBTRB = 11
WRT0,EBTR0 = 10
WRT1,EBTR1 = 11
WRT2,EBTR2 = 11
WRT3,EBTR3 = 11
TBLRD *
TBLPTR = 000FFF
PC = 001FFE
Register Values Program Memory Configuration Bit Settings
Results: Table Reads permitted within Blockn, even when EBTRBn = ‘0’.
TABLAT register returns the value of the data at the location TBLPTR.PIC18FXX2
DS39564C-page 210 © 2006 Microchip Technology Inc.
19.4.2 DATA EEPROM
CODE PROTECTION
The entire Data EEPROM is protected from external
reads and writes by two bits: CPD and WRTD. CPD
inhibits external reads and writes of Data EEPROM.
WRTD inhibits external writes to Data EEPROM. The
CPU can continue to read and write Data EEPROM
regardless of the protection bit settings.
19.4.3 CONFIGURATION REGISTER
PROTECTION
The configuration registers can be write protected. The
WRTC bit controls protection of the configuration registers.
In User mode, the WRTC bit is readable only. WRTC
can only be written via ICSP or an external programmer.
19.5 ID Locations
Eight memory locations (200000h - 200007h) are designated
as ID locations, where the user can store
checksum or other code identification numbers. These
locations are accessible during normal execution
through the TBLRD and TBLWT instructions, or during
program/verify. The ID locations can be read when the
device is code protected.
The sequence for programming the ID locations is similar
to programming the FLASH memory (see
Section 5.5.1).
19.6 In-Circuit Serial Programming
PIC18FXXX microcontrollers can be serially programmed
while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
19.7 In-Circuit Debugger
When the DEBUG bit in configuration register
CONFIG4L is programmed to a '0', the In-Circuit
Debugger functionality is enabled. This function allows
simple debugging functions when used with MPLAB®
IDE. When the microcontroller has this feature
enabled, some of the resources are not available for
general use. Table 19-4 shows which features are
consumed by the background debugger.
TABLE 19-4: DEBUGGER RESOURCES
To use the In-Circuit Debugger function of the microcontroller,
the design must implement In-Circuit Serial
Programming connections to MCLR/VPP, VDD, GND,
RB7 and RB6. This will interface to the In-Circuit
Debugger module available from Microchip or one of
the third party development tool companies.
19.8 Low Voltage ICSP Programming
The LVP bit configuration register CONFIG4L enables
low voltage ICSP programming. This mode allows the
microcontroller to be programmed via ICSP using a
VDD source in the operating voltage range. This only
means that VPP does not have to be brought to VIHH,
but can instead be left at the normal operating voltage.
In this mode, the RB5/PGM pin is dedicated to the programming
function and ceases to be a general purpose
I/O pin. During programming, VDD is applied to the
MCLR/VPP pin. To enter Programming mode, VDD must
be applied to the RB5/PGM, provided the LVP bit is set.
The LVP bit defaults to a (‘1’) from the factory.
If Low Voltage Programming mode is not used, the LVP
bit can be programmed to a '0' and RB5/PGM becomes
a digital I/O pin. However, the LVP bit may only be programmed
when programming is entered with VIHH on
MCLR/VPP.
It should be noted that once the LVP bit is programmed
to 0, only the High Voltage Programming mode is available
and only High Voltage Programming mode can be
used to program the device.
When using low voltage ICSP, the part must be supplied
4.5V to 5.5V, if a bulk erase will be executed. This
includes reprogramming of the code protect bits from
an on-state to off-state. For all other cases of low voltage
ICSP, the part may be programmed at the normal
operating voltage. This means unique user IDs, or user
code can be reprogrammed or added. I/O pins RB6, RB7
Stack 2 levels
Program Memory 512 bytes
Data Memory 10 bytes
Note 1: The High Voltage Programming mode is
always available, regardless of the state
of the LVP bit, by applying VIHH to the
MCLR pin.
2: While in low voltage ICSP mode, the RB5
pin can no longer be used as a general
purpose I/O pin, and should be held low
during normal operation to protect
against inadvertent ICSP mode entry.
3: When using low voltage ICSP programming
(LVP), the pull-up on RB5 becomes
disabled. If TRISB bit 5 is cleared,
thereby setting RB5 as an output, LATB
bit 5 must also be cleared for proper
operation.© 2006 Microchip Technology Inc. DS39564C-page 211
PIC18FXX2
20.0 INSTRUCTION SET SUMMARY
The PIC18FXXX instruction set adds many enhancements
to the previous PICmicro instruction sets, while
maintaining an easy migration from these PICmicro
instruction sets.
Most instructions are a single program memory word
(16-bits), but there are three instructions that require
two program memory locations.
Each single word instruction is a 16-bit word divided
into an OPCODE, which specifies the instruction type
and one or more operands, which further specify the
operation of the instruction.
The instruction set is highly orthogonal and is grouped
into four basic categories:
• Byte-oriented operations
• Bit-oriented operations
• Literal operations
• Control operations
The PIC18FXXX instruction set summary in Table 20-2
lists byte-oriented, bit-oriented, literal and control
operations. Table 20-1 shows the opcode field
descriptions.
Most byte-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The destination of the result
(specified by ‘d’)
3. The accessed memory
(specified by ‘a’)
The file register designator 'f' specifies which file
register is to be used by the instruction.
The destination designator ‘d’ specifies where the
result of the operation is to be placed. If 'd' is zero, the
result is placed in the WREG register. If 'd' is one, the
result is placed in the file register specified in the
instruction.
All bit-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The bit in the file register
(specified by ‘b’)
3. The accessed memory
(specified by ‘a’)
The bit field designator 'b' selects the number of the bit
affected by the operation, while the file register designator
'f' represents the number of the file in which the
bit is located.
The literal instructions may use some of the following
operands:
• A literal value to be loaded into a file register
(specified by ‘k’)
• The desired FSR register to load the literal value
into (specified by ‘f’)
• No operand required
(specified by ‘—’)
The control instructions may use some of the following
operands:
• A program memory address (specified by ‘n’)
• The mode of the Call or Return instructions
(specified by ‘s’)
• The mode of the Table Read and Table Write
instructions (specified by ‘m’)
• No operand required
(specified by ‘—’)
All instructions are a single word, except for three double-word
instructions. These three instructions were
made double-word instructions so that all the required
information is available in these 32 bits. In the second
word, the 4-MSbs are 1’s. If this second word is executed
as an instruction (by itself), it will execute as a
NOP.
All single word instructions are executed in a single
instruction cycle, unless a conditional test is true or the
program counter is changed as a result of the instruction.
In these cases, the execution takes two instruction
cycles with the additional instruction cycle(s) executed
as a NOP.
The double-word instructions execute in two instruction
cycles.
One instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 μs. If a conditional test is
true or the program counter is changed as a result of an
instruction, the instruction execution time is 2 μs.
Two-word branch instructions (if true) would take 3 μs.
Figure 20-1 shows the general formats that the
instructions can have.
All examples use the format ‘nnh’ to represent a
hexadecimal number, where ‘h’ signifies a
hexadecimal digit.
The Instruction Set Summary, shown in Table 20-2,
lists the instructions recognized by the Microchip
Assembler (MPASMTM).
Section 20.1 provides a description of each instruction.PIC18FXX2
DS39564C-page 212 © 2006 Microchip Technology Inc.
TABLE 20-1: OPCODE FIELD DESCRIPTIONS
Field Description
a RAM access bit
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb Bit address within an 8-bit file register (0 to 7)
BSR Bank Select Register. Used to select the current RAM bank.
d Destination select bit;
d = 0: store result in WREG,
d = 1: store result in file register f.
dest Destination either the WREG register or the specified register file location
f 8-bit Register file address (0x00 to 0xFF)
fs 12-bit Register file address (0x000 to 0xFFF). This is the source address.
fd 12-bit Register file address (0x000 to 0xFFF). This is the destination address.
k Literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value)
label Label name
mm The mode of the TBLPTR register for the Table Read and Table Write instructions.
Only used with Table Read and Table Write instructions:
* No Change to register (such as TBLPTR with Table reads and writes)
*+ Post-Increment register (such as TBLPTR with Table reads and writes)
*- Post-Decrement register (such as TBLPTR with Table reads and writes)
+* Pre-Increment register (such as TBLPTR with Table reads and writes)
n The relative address (2’s complement number) for relative branch instructions, or the direct address for
Call/Branch and Return instructions
PRODH Product of Multiply high byte
PRODL Product of Multiply low byte
s Fast Call/Return mode select bit.
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
u Unused or Unchanged
WREG Working register (accumulator)
x Don't care (0 or 1)
The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all
Microchip software tools.
TBLPTR 21-bit Table Pointer (points to a Program Memory location)
TABLAT 8-bit Table Latch
TOS Top-of-Stack
PC Program Counter
PCL Program Counter Low Byte
PCH Program Counter High Byte
PCLATH Program Counter High Byte Latch
PCLATU Program Counter Upper Byte Latch
GIE Global Interrupt Enable bit
WDT Watchdog Timer
TO Time-out bit
PD Power-down bit
C, DC, Z, OV, N ALU status bits Carry, Digit Carry, Zero, Overflow, Negative
[ ] Optional
( ) Contents
→ Assigned to
< > Register bit field
∈ In the set of
italics User defined term (font is courier)© 2006 Microchip Technology Inc. DS39564C-page 213
PIC18FXX2
FIGURE 20-1: GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15 10 9 8 7 0
d = 0 for result destination to be WREG register
OPCODE d a f (FILE #)
d = 1 for result destination to be file register (f)
a = 0 to force Access Bank
Bit-oriented file register operations
15 12 11 9 8 7 0
OPCODE b (BIT #) a f (FILE #)
b = 3-bit position of bit in file register (f)
Literal operations
15 8 7 0
OPCODE k (literal)
k = 8-bit immediate value
Byte to Byte move operations (2-word)
15 12 11 0
OPCODE f (Source FILE #)
CALL, GOTO and Branch operations
15 8 7 0
OPCODE n<7:0> (literal)
n = 20-bit immediate value
a = 1 for BSR to select bank
f = 8-bit file register address
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
15 12 11 0
1111 n<19:8> (literal)
15 12 11 0
1111 f (Destination FILE #)
f = 12-bit file register address
Control operations
Example Instruction
ADDWF MYREG, W, B
MOVFF MYREG1, MYREG2
BSF MYREG, bit, B
MOVLW 0x7F
GOTO Label
15 8 7 0
OPCODE n<7:0> (literal)
15 12 11 0
n<19:8> (literal)
CALL MYFUNC
15 11 10 0
OPCODE n<10:0> (literal)
S = Fast bit
BRA MYFUNC
15 8 7 0
OPCODE n<7:0> (literal) BC MYFUNC
SPIC18FXX2
DS39564C-page 214 © 2006 Microchip Technology Inc.
TABLE 20-2: PIC18FXXX INSTRUCTION SET
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ADDWFC
ANDWF
CLRF
COMF
CPFSEQ
CPFSGT
CPFSLT
DECF
DECFSZ
DCFSNZ
INCF
INCFSZ
INFSNZ
IORWF
MOVF
MOVFF
MOVWF
MULWF
NEGF
RLCF
RLNCF
RRCF
RRNCF
SETF
SUBFWB
SUBWF
SUBWFB
SWAPF
TSTFSZ
XORWF
f, d, a
f, d, a
f, d, a
f, a
f, d, a
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
fs, fd
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, a
f, d, a
Add WREG and f
Add WREG and Carry bit to f
AND WREG with f
Clear f
Complement f
Compare f with WREG, skip =
Compare f with WREG, skip >
Compare f with WREG, skip <
Decrement f
Decrement f, Skip if 0
Decrement f, Skip if Not 0
Increment f
Increment f, Skip if 0
Increment f, Skip if Not 0
Inclusive OR WREG with f
Move f
Move fs (source) to 1st word
fd (destination) 2nd word
Move WREG to f
Multiply WREG with f
Negate f
Rotate Left f through Carry
Rotate Left f (No Carry)
Rotate Right f through Carry
Rotate Right f (No Carry)
Set f
Subtract f from WREG with
borrow
Subtract WREG from f
Subtract WREG from f with
borrow
Swap nibbles in f
Test f, skip if 0
Exclusive OR WREG with f
1
1
1
1
1
1 (2 or 3)
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1 (2 or 3)
1
0010
0010
0001
0110
0001
0110
0110
0110
0000
0010
0100
0010
0011
0100
0001
0101
1100
1111
0110
0000
0110
0011
0100
0011
0100
0110
0101
0101
0101
0011
0110
0001
01da0
0da
01da
101a
11da
001a
010a
000a
01da
11da
11da
10da
11da
10da
00da
00da
ffff
ffff
111a
001a
110a
01da
01da
00da
00da
100a
01da
11da
10da
10da
011a
10da
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
C, DC, Z, OV, N
C, DC, Z, OV, N
Z, N
Z
Z, N
None
None
None
C, DC, Z, OV, N
None
None
C, DC, Z, OV, N
None
None
Z, N
Z, N
None
None
None
C, DC, Z, OV, N
C, Z, N
Z, N
C, Z, N
Z, N
None
C, DC, Z, OV, N
C, DC, Z, OV, N
C, DC, Z, OV, N
None
None
Z, N
1, 2
1, 2
1,2
2
1, 2
4
4
1, 2
1, 2, 3, 4
1, 2, 3, 4
1, 2
1, 2, 3, 4
4
1, 2
1, 2
1
1, 2
1, 2
1, 2
1, 2
4
1, 2
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
BTFSC
BTFSS
BTG
f, b, a
f, b, a
f, b, a
f, b, a
f, d, a
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
Bit Toggle f
1
1
1 (2 or 3)
1 (2 or 3)
1
1001
1000
1011
1010
0111
bbba
bbba
bbba
bbba
bbba
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
None
None
None
None
None
1, 2
1, 2
3, 4
3, 4
1, 2
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an
external device, the data will be written back with a '0'.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is
executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the
first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory
locations have a valid instruction.
5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.© 2006 Microchip Technology Inc. DS39564C-page 215
PIC18FXX2
CONTROL OPERATIONS
BC
BN
BNC
BNN
BNOV
BNZ
BOV
BRA
BZ
CALL
CLRWDT
DAW
GOTO
NOP
NOP
POP
PUSH
RCALL
RESET
RETFIE
RETLW
RETURN
SLEEP
n
n
n
n
n
n
n
n
n
n, s
—
—
n
—
—
—
—
n
s
k
s
—
Branch if Carry
Branch if Negative
Branch if Not Carry
Branch if Not Negative
Branch if Not Overflow
Branch if Not Zero
Branch if Overflow
Branch Unconditionally
Branch if Zero
Call subroutine1st word
2nd word
Clear Watchdog Timer
Decimal Adjust WREG
Go to address1st word
2nd word
No Operation
No Operation
Pop top of return stack (TOS)
Push top of return stack (TOS)
Relative Call
Software device RESET
Return from interrupt enable
Return with literal in WREG
Return from Subroutine
Go into Standby mode
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
1 (2)
1 (2)
2
1
1
2
1
1
1
1
2
1
2
2
2
1
1110
1110
1110
1110
1110
1110
1110
1101
1110
1110
1111
0000
0000
1110
1111
0000
1111
0000
0000
1101
0000
0000
0000
0000
0000
0010
0110
0011
0111
0101
0001
0100
0nnn
0000
110s
kkkk
0000
0000
1111
kkkk
0000
xxxx
0000
0000
1nnn
0000
0000
1100
0000
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0000
0000
kkkk
kkkk
0000
xxxx
0000
0000
nnnn
1111
0001
kkkk
0001
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0100
0111
kkkk
kkkk
0000
xxxx
0110
0101
nnnn
1111
000s
kkkk
001s
0011
None
None
None
None
None
None
None
None
None
None
TO, PD
C
None
None
None
None
None
None
All
GIE/GIEH,
PEIE/GIEL
None
None
TO, PD
4
TABLE 20-2: PIC18FXXX INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an
external device, the data will be written back with a '0'.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is
executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the
first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory
locations have a valid instruction.
5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.PIC18FXX2
DS39564C-page 216 © 2006 Microchip Technology Inc.
LITERAL OPERATIONS
ADDLW
ANDLW
IORLW
LFSR
MOVLB
MOVLW
MULLW
RETLW
SUBLW
XORLW
k
k
k
f, k
k
k
k
k
k
k
Add literal and WREG
AND literal with WREG
Inclusive OR literal with WREG
Move literal (12-bit) 2nd word
to FSRx 1st word
Move literal to BSR<3:0>
Move literal to WREG
Multiply literal with WREG
Return with literal in WREG
Subtract WREG from literal
Exclusive OR literal with WREG
1
1
1
2
1
1
1
2
1
1
0000
0000
0000
1110
1111
0000
0000
0000
0000
0000
0000
1111
1011
1001
1110
0000
0001
1110
1101
1100
1000
1010
kkkk
kkkk
kkkk
00ff
kkkk
0000
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
C, DC, Z, OV, N
Z, N
Z, N
None
None
None
None
None
C, DC, Z, OV, N
Z, N
DATA MEMORY ↔ PROGRAM MEMORY OPERATIONS
TBLRD*
TBLRD*+
TBLRD*-
TBLRD+*
TBLWT*
TBLWT*+
TBLWT*-
TBLWT+*
Table Read
Table Read with post-increment
Table Read with post-decrement
Table Read with pre-increment
Table Write
Table Write with post-increment
Table Write with post-decrement
Table Write with pre-increment
2
2 (5)
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
1000
1001
1010
1011
1100
1101
1110
1111
None
None
None
None
None
None
None
None
TABLE 20-2: PIC18FXXX INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an
external device, the data will be written back with a '0'.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is
executed as a NOP.
4: Some instructions are 2-word instructions. The second word of these instructions will be executed as a NOP, unless the
first word of the instruction retrieves the information embedded in these 16-bits. This ensures that all program memory
locations have a valid instruction.
5: If the Table Write starts the write cycle to internal memory, the write will continue until terminated.© 2006 Microchip Technology Inc. DS39564C-page 217
PIC18FXX2
20.1 Instruction Set
ADDLW ADD literal to W
Syntax: [ label ] ADDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) + k → W
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1111 kkkk kkkk
Description: The contents of W are added to the
8-bit literal 'k' and the result is
placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write to W
Example: ADDLW 0x15
Before Instruction
W = 0x10
After Instruction
W = 0x25
ADDWF ADD W to f
Syntax: [ label ] ADDWF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) + (f) → dest
Status Affected: N, OV, C, DC, Z
Encoding: 0010 01da ffff ffff
Description: Add W to register 'f'. If 'd' is 0, the
result is stored in W. If 'd' is 1, the
result is stored back in register 'f'
(default). If ‘a’ is 0, the Access
Bank will be selected. If ‘a’ is 1, the
BSR is used.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: ADDWF REG, 0, 0
Before Instruction
W = 0x17
REG = 0xC2
After Instruction
W = 0xD9
REG = 0xC2PIC18FXX2
DS39564C-page 218 © 2006 Microchip Technology Inc.
ADDWFC ADD W and Carry bit to f
Syntax: [ label ] ADDWFC f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) + (f) + (C) → dest
Status Affected: N,OV, C, DC, Z
Encoding: 0010 00da ffff ffff
Description: Add W, the Carry Flag and data
memory location 'f'. If 'd' is 0, the
result is placed in W. If 'd' is 1, the
result is placed in data memory location
'f'. If ‘a’ is 0, the Access Bank
will be selected. If ‘a’ is 1, the BSR
will not be overridden.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: ADDWFC REG, 0, 1
Before Instruction
Carry bit = 1
REG = 0x02
W = 0x4D
After Instruction
Carry bit = 0
REG = 0x02
W = 0x50
ANDLW AND literal with W
Syntax: [ label ] ANDLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .AND. k → W
Status Affected: N,Z
Encoding: 0000 1011 kkkk kkkk
Description: The contents of W are ANDed with
the 8-bit literal 'k'. The result is
placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'k'
Process
Data
Write to W
Example: ANDLW 0x5F
Before Instruction
W = 0xA3
After Instruction
W = 0x03© 2006 Microchip Technology Inc. DS39564C-page 219
PIC18FXX2
ANDWF AND W with f
Syntax: [ label ] ANDWF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) .AND. (f) → dest
Status Affected: N,Z
Encoding: 0001 01da ffff ffff
Description: The contents of W are AND’ed with
register 'f'. If 'd' is 0, the result is
stored in W. If 'd' is 1, the result is
stored back in register 'f' (default). If
‘a’ is 0, the Access Bank will be
selected. If ‘a’ is 1, the BSR will not
be overridden (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: ANDWF REG, 0, 0
Before Instruction
W = 0x17
REG = 0xC2
After Instruction
W = 0x02
REG = 0xC2
BC Branch if Carry
Syntax: [ label ] BC n
Operands: -128 ≤ n ≤ 127
Operation: if carry bit is ’1’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0010 nnnn nnnn
Description: If the Carry bit is ’1’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BC 5
Before Instruction
PC = address (HERE)
After Instruction
If Carry = 1;
PC = address (HERE+12)
If Carry = 0;
PC = address (HERE+2)PIC18FXX2
DS39564C-page 220 © 2006 Microchip Technology Inc.
BCF Bit Clear f
Syntax: [ label ] BCF f,b[,a]
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: 0 → f
Status Affected: None
Encoding: 1001 bbba ffff ffff
Description: Bit 'b' in register 'f' is cleared. If ‘a’
is 0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: BCF FLAG_REG, 7, 0
Before Instruction
FLAG_REG = 0xC7
After Instruction
FLAG_REG = 0x47
BN Branch if Negative
Syntax: [ label ] BN n
Operands: -128 ≤ n ≤ 127
Operation: if negative bit is ’1’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0110 nnnn nnnn
Description: If the Negative bit is ’1’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BN Jump
Before Instruction
PC = address (HERE)
After Instruction
If Negative = 1;
PC = address (Jump)
If Negative = 0;
PC = address (HERE+2)© 2006 Microchip Technology Inc. DS39564C-page 221
PIC18FXX2
BNC Branch if Not Carry
Syntax: [ label ] BNC n
Operands: -128 ≤ n ≤ 127
Operation: if carry bit is ’0’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0011 nnnn nnnn
Description: If the Carry bit is ’0’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BNC Jump
Before Instruction
PC = address (HERE)
After Instruction
If Carry = 0;
PC = address (Jump)
If Carry = 1;
PC = address (HERE+2)
BNN Branch if Not Negative
Syntax: [ label ] BNN n
Operands: -128 ≤ n ≤ 127
Operation: if negative bit is ’0’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0111 nnnn nnnn
Description: If the Negative bit is ’0’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BNN Jump
Before Instruction
PC = address (HERE)
After Instruction
If Negative = 0;
PC = address (Jump)
If Negative = 1;
PC = address (HERE+2)PIC18FXX2
DS39564C-page 222 © 2006 Microchip Technology Inc.
BNOV Branch if Not Overflow
Syntax: [ label ] BNOV n
Operands: -128 ≤ n ≤ 127
Operation: if overflow bit is ’0’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0101 nnnn nnnn
Description: If the Overflow bit is ’0’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BNOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If Overflow = 0;
PC = address (Jump)
If Overflow = 1;
PC = address (HERE+2)
BNZ Branch if Not Zero
Syntax: [ label ] BNZ n
Operands: -128 ≤ n ≤ 127
Operation: if zero bit is ’0’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0001 nnnn nnnn
Description: If the Zero bit is ’0’, then the program
will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BNZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If Zero = 0;
PC = address (Jump)
If Zero = 1;
PC = address (HERE+2)© 2006 Microchip Technology Inc. DS39564C-page 223
PIC18FXX2
BRA Unconditional Branch
Syntax: [ label ] BRA n
Operands: -1024 ≤ n ≤ 1023
Operation: (PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1101 0nnn nnnn nnnn
Description: Add the 2’s complement number
’2n’ to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is a
two-cycle instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE BRA Jump
Before Instruction
PC = address (HERE)
After Instruction
PC = address (Jump)
BSF Bit Set f
Syntax: [ label ] BSF f,b[,a]
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: 1 → f
Status Affected: None
Encoding: 1000 bbba ffff ffff
Description: Bit 'b' in register 'f' is set. If ‘a’ is 0
Access Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: BSF FLAG_REG, 7, 1
Before Instruction
FLAG_REG = 0x0A
After Instruction
FLAG_REG = 0x8APIC18FXX2
DS39564C-page 224 © 2006 Microchip Technology Inc.
BTFSC Bit Test File, Skip if Clear
Syntax: [ label ] BTFSC f,b[,a]
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: skip if (f) = 0
Status Affected: None
Encoding: 1011 bbba ffff ffff
Description: If bit 'b' in register ’f' is 0, then the
next instruction is skipped.
If bit 'b' is 0, then the next instruction
fetched during the current instruction
execution is discarded, and a NOP is
executed instead, making this a twocycle
instruction. If ‘a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSC
:
:
FLAG, 1, 0
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (TRUE)
If FLAG<1> = 1;
PC = address (FALSE)
BTFSS Bit Test File, Skip if Set
Syntax: [ label ] BTFSS f,b[,a]
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: skip if (f) = 1
Status Affected: None
Encoding: 1010 bbba ffff ffff
Description: If bit 'b' in register 'f' is 1, then the
next instruction is skipped.
If bit 'b' is 1, then the next instruction
fetched during the current instruction
execution, is discarded and a
NOP is executed instead, making this
a two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process Data No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSS
:
:
FLAG, 1, 0
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (FALSE)
If FLAG<1> = 1;
PC = address (TRUE)© 2006 Microchip Technology Inc. DS39564C-page 225
PIC18FXX2
BTG Bit Toggle f
Syntax: [ label ] BTG f,b[,a]
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: (f) → f
Status Affected: None
Encoding: 0111 bbba ffff ffff
Description: Bit 'b' in data memory location 'f' is
inverted. If ‘a’ is 0, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: BTG PORTC, 4, 0
Before Instruction:
PORTC = 0111 0101 [0x75]
After Instruction:
PORTC = 0110 0101 [0x65]
BOV Branch if Overflow
Syntax: [ label ] BOV n
Operands: -128 ≤ n ≤ 127
Operation: if overflow bit is ’1’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0100 nnnn nnnn
Description: If the Overflow bit is ’1’, then the
program will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If Overflow = 1;
PC = address (Jump)
If Overflow = 0;
PC = address (HERE+2)PIC18FXX2
DS39564C-page 226 © 2006 Microchip Technology Inc.
BZ Branch if Zero
Syntax: [ label ] BZ n
Operands: -128 ≤ n ≤ 127
Operation: if Zero bit is ’1’
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1110 0000 nnnn nnnn
Description: If the Zero bit is ’1’, then the program
will branch.
The 2’s complement number ’2n’ is
added to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC+2+2n. This instruction is then
a two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Process
Data
No
operation
Example: HERE BZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If Zero = 1;
PC = address (Jump)
If Zero = 0;
PC = address (HERE+2)
CALL Subroutine Call
Syntax: [ label ] CALL k [,s]
Operands: 0 ≤ k ≤ 1048575
s ∈ [0,1]
Operation: (PC) + 4 → TOS,
k → PC<20:1>,
if s = 1
(W) → WS,
(STATUS) → STATUSS,
(BSR) → BSRS
Status Affected: None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
110s
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: Subroutine call of entire 2 Mbyte
memory range. First, return
address (PC+ 4) is pushed onto the
return stack. If ’s’ = 1, the W,
STATUS and BSR registers are
also pushed into their respective
shadow registers, WS, STATUSS
and BSRS. If 's' = 0, no update
occurs (default). Then, the 20-bit
value ’k’ is loaded into PC<20:1>.
CALL is a two-cycle instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'k'<7:0>,
Push PC to
stack
Read literal
’k’<19:8>,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE CALL THERE,1
Before Instruction
PC = address (HERE)
After Instruction
PC = address (THERE)
TOS = address (HERE + 4)
WS = W
BSRS = BSR
STATUSS= STATUS© 2006 Microchip Technology Inc. DS39564C-page 227
PIC18FXX2
CLRF Clear f
Syntax: [ label ] CLRF f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: 000h → f
1 → Z
Status Affected: Z
Encoding: 0110 101a ffff ffff
Description: Clears the contents of the specified
register. If ‘a’ is 0, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will
be selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: CLRF FLAG_REG,1
Before Instruction
FLAG_REG = 0x5A
After Instruction
FLAG_REG = 0x00
CLRWDT Clear Watchdog Timer
Syntax: [ label ] CLRWDT
Operands: None
Operation: 000h → WDT,
000h → WDT postscaler,
1 → TO,
1 → PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0100
Description: CLRWDT instruction resets the
Watchdog Timer. It also resets the
postscaler of the WDT. Status bits
TO and PD are set.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
No
operation
Example: CLRWDT
Before Instruction
WDT Counter = ?
After Instruction
WDT Counter = 0x00
WDT Postscaler = 0
TO = 1
PD = 1PIC18FXX2
DS39564C-page 228 © 2006 Microchip Technology Inc.
COMF Complement f
Syntax: [ label ] COMF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: → dest
Status Affected: N, Z
Encoding: 0001 11da ffff ffff
Description: The contents of register 'f' are complemented.
If 'd' is 0, the result is
stored in W. If 'd' is 1, the result is
stored back in register 'f' (default). If
‘a’ is 0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: COMF REG, 0, 0
Before Instruction
REG = 0x13
After Instruction
REG = 0x13
W = 0xEC
(f)
CPFSEQ Compare f with W, skip if f = W
Syntax: [ label ] CPFSEQ f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: (f) – (W),
skip if (f) = (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 001a ffff ffff
Description: Compares the contents of data
memory location 'f' to the contents
of W by performing an unsigned
subtraction.
If 'f' = W, then the fetched instruction
is discarded and a NOP is executed
instead, making this a twocycle
instruction. If ‘a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSEQ REG, 0
NEQUAL :
EQUAL :
Before Instruction
PC Address = HERE
W =?
REG = ?
After Instruction
If REG = W;
PC = Address (EQUAL)
If REG ≠ W;
PC = Address (NEQUAL)© 2006 Microchip Technology Inc. DS39564C-page 229
PIC18FXX2
CPFSGT Compare f with W, skip if f > W
Syntax: [ label ] CPFSGT f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: (f) − (W),
skip if (f) > (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 010a ffff ffff
Description: Compares the contents of data
memory location 'f' to the contents
of the W by performing an
unsigned subtraction.
If the contents of 'f' are greater than
the contents of WREG, then the
fetched instruction is discarded and
a NOP is executed instead, making
this a two-cycle instruction. If ‘a’ is
0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSGT REG, 0
NGREATER :
GREATER :
Before Instruction
PC = Address (HERE)
W = ?
After Instruction
If REG > W;
PC = Address (GREATER)
If REG ≤ W;
PC = Address (NGREATER)
CPFSLT Compare f with W, skip if f < W
Syntax: [ label ] CPFSLT f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: (f) – (W),
skip if (f) < (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 000a ffff ffff
Description: Compares the contents of data
memory location 'f' to the contents
of W by performing an unsigned
subtraction.
If the contents of 'f' are less than
the contents of W, then the fetched
instruction is discarded and a NOP
is executed instead, making this a
two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected. If ’a’
is 1, the BSR will not be overridden
(default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSLT REG, 1
NLESS :
LESS :
Before Instruction
PC = Address (HERE)
W = ?
After Instruction
If REG < W;
PC = Address (LESS)
If REG ≥ W;
PC = Address (NLESS)PIC18FXX2
DS39564C-page 230 © 2006 Microchip Technology Inc.
DAW Decimal Adjust W Register
Syntax: [ label ] DAW
Operands: None
Operation: If [W<3:0> >9] or [DC = 1] then
(W<3:0>) + 6 → W<3:0>;
else
(W<3:0>) → W<3:0>;
If [W<7:4> >9] or [C = 1] then
(W<7:4>) + 6 → W<7:4>;
else
(W<7:4>) → W<7:4>;
Status Affected: C
Encoding: 0000 0000 0000 0111
Description: DAW adjusts the eight-bit value in
W, resulting from the earlier addition
of two variables (each in
packed BCD format) and produces
a correct packed BCD result.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register W
Process
Data
Write
W
Example1: DAW
Before Instruction
W = 0xA5
C =0
DC = 0
After Instruction
W = 0x05
C =1
DC = 0
Example 2:
Before Instruction
W = 0xCE
C =0
DC = 0
After Instruction
W = 0x34
C =1
DC = 0
DECF Decrement f
Syntax: [ label ] DECF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) – 1 → dest
Status Affected: C, DC, N, OV, Z
Encoding: 0000 01da ffff ffff
Description: Decrement register 'f'. If 'd' is 0, the
result is stored in W. If 'd' is 1, the
result is stored back in register 'f'
(default). If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: DECF CNT, 1, 0
Before Instruction
CNT = 0x01
Z =0
After Instruction
CNT = 0x00
Z =1© 2006 Microchip Technology Inc. DS39564C-page 231
PIC18FXX2
DECFSZ Decrement f, skip if 0
Syntax: [ label ] DECFSZ f [,d [,a]]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) – 1 → dest,
skip if result = 0
Status Affected: None
Encoding: 0010 11da ffff ffff
Description: The contents of register 'f' are decremented.
If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If the result is 0, the next instruction,
which is already fetched, is
discarded, and a NOP is executed
instead, making it a two-cycle
instruction. If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DECFSZ CNT, 1, 1
GOTO LOOP
CONTINUE
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT - 1
If CNT = 0;
PC = Address (CONTINUE)
If CNT ≠ 0;
PC = Address (HERE+2)
DCFSNZ Decrement f, skip if not 0
Syntax: [ label ] DCFSNZ f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) – 1 → dest,
skip if result ≠ 0
Status Affected: None
Encoding: 0100 11da ffff ffff
Description: The contents of register 'f' are decremented.
If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If the result is not 0, the next
instruction, which is already
fetched, is discarded, and a NOP is
executed instead, making it a twocycle
instruction. If ’a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If ’a’ = 1,
then the bank will be selected as
per the BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DCFSNZ TEMP, 1, 0
ZERO :
NZERO :
Before Instruction
TEMP = ?
After Instruction
TEMP = TEMP - 1,
If TEMP = 0;
PC = Address (ZERO)
If TEMP ≠ 0;
PC = Address (NZERO)PIC18FXX2
DS39564C-page 232 © 2006 Microchip Technology Inc.
GOTO Unconditional Branch
Syntax: [ label ] GOTO k
Operands: 0 ≤ k ≤ 1048575
Operation: k → PC<20:1>
Status Affected: None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: GOTO allows an unconditional
branch anywhere within entire
2 Mbyte memory range. The 20-bit
value ’k’ is loaded into PC<20:1>.
GOTO is always a two-cycle
instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'k'<7:0>,
No
operation
Read literal
’k’<19:8>,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: GOTO THERE
After Instruction
PC = Address (THERE)
INCF Increment f
Syntax: [ label ] INCF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) + 1 → dest
Status Affected: C, DC, N, OV, Z
Encoding: 0010 10da ffff ffff
Description: The contents of register 'f' are
incremented. If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If ’a’ is 0, the Access Bank will be
selected, overriding the BSR value.
If ’a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: INCF CNT, 1, 0
Before Instruction
CNT = 0xFF
Z =0
C =?
DC = ?
After Instruction
CNT = 0x00
Z =1
C =1
DC = 1© 2006 Microchip Technology Inc. DS39564C-page 233
PIC18FXX2
INCFSZ Increment f, skip if 0
Syntax: [ label ] INCFSZ f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) + 1 → dest,
skip if result = 0
Status Affected: None
Encoding: 0011 11da ffff ffff
Description: The contents of register 'f' are
incremented. If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f'. (default)
If the result is 0, the next instruction,
which is already fetched, is
discarded, and a NOP is executed
instead, making it a two-cycle
instruction. If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INCFSZ CNT, 1, 0
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT + 1
If CNT = 0;
PC = Address (ZERO)
If CNT ≠ 0;
PC = Address (NZERO)
INFSNZ Increment f, skip if not 0
Syntax: [ label ] INFSNZ f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) + 1 → dest,
skip if result ≠ 0
Status Affected: None
Encoding: 0100 10da ffff ffff
Description: The contents of register 'f' are
incremented. If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If the result is not 0, the next
instruction, which is already
fetched, is discarded, and a NOP is
executed instead, making it a twocycle
instruction. If ’a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ’a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INFSNZ REG, 1, 0
ZERO
NZERO
Before Instruction
PC = Address (HERE)
After Instruction
REG = REG + 1
If REG ≠ 0;
PC = Address (NZERO)
If REG = 0;
PC = Address (ZERO)PIC18FXX2
DS39564C-page 234 © 2006 Microchip Technology Inc.
IORLW Inclusive OR literal with W
Syntax: [ label ] IORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .OR. k → W
Status Affected: N, Z
Encoding: 0000 1001 kkkk kkkk
Description: The contents of W are OR’ed with
the eight-bit literal 'k'. The result is
placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write to W
Example: IORLW 0x35
Before Instruction
W = 0x9A
After Instruction
W = 0xBF
IORWF Inclusive OR W with f
Syntax: [ label ] IORWF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) .OR. (f) → dest
Status Affected: N, Z
Encoding: 0001 00da ffff ffff
Description: Inclusive OR W with register 'f'. If 'd'
is 0, the result is placed in W. If 'd'
is 1, the result is placed back in
register 'f' (default). If ’a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ’a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: IORWF RESULT, 0, 1
Before Instruction
RESULT = 0x13
W = 0x91
After Instruction
RESULT = 0x13
W = 0x93© 2006 Microchip Technology Inc. DS39564C-page 235
PIC18FXX2
LFSR Load FSR
Syntax: [ label ] LFSR f,k
Operands: 0 ≤ f ≤ 2
0 ≤ k ≤ 4095
Operation: k → FSRf
Status Affected: None
Encoding: 1110
1111
1110
0000
00ff
k7kkk
k11kkk
kkkk
Description: The 12-bit literal 'k' is loaded into
the file select register pointed to
by 'f'.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'k' MSB
Process
Data
Write
literal 'k'
MSB to
FSRfH
Decode Read literal
'k' LSB
Process
Data
Write literal
'k' to FSRfL
Example: LFSR 2, 0x3AB
After Instruction
FSR2H = 0x03
FSR2L = 0xAB
MOVF Move f
Syntax: [ label ] MOVF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: f → dest
Status Affected: N, Z
Encoding: 0101 00da ffff ffff
Description: The contents of register 'f' are
moved to a destination dependent
upon the status of ’d’. If 'd' is 0, the
result is placed in W. If 'd' is 1, the
result is placed back in register 'f'
(default). Location 'f' can be anywhere
in the 256 byte bank. If ’a’ is
0, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write W
Example: MOVF REG, 0, 0
Before Instruction
REG = 0x22
W = 0xFF
After Instruction
REG = 0x22
W = 0x22PIC18FXX2
DS39564C-page 236 © 2006 Microchip Technology Inc.
MOVFF Move f to f
Syntax: [ label ] MOVFF fs,fd
Operands: 0 ≤ fs ≤ 4095
0 ≤ fd ≤ 4095
Operation: (fs) → fd
Status Affected: None
Encoding:
1st word (source)
2nd word (destin.)
1100
1111
ffff
ffff
ffff
ffff
ffffs
ffffd
Description: The contents of source register 'fs'
are moved to destination register
'fd'. Location of source 'fs' can be
anywhere in the 4096 byte data
space (000h to FFFh), and location
of destination 'fd' can also be anywhere
from 000h to FFFh.
Either source or destination can be
W (a useful special situation).
MOVFF is particularly useful for
transferring a data memory location
to a peripheral register (such as the
transmit buffer or an I/O port).
The MOVFF instruction cannot use
the PCL, TOSU, TOSH or TOSL as
the destination register.
Note: The MOVFF instruction
should not be used to modify
interrupt settings while
any interrupt is enabled.
See Section 8.0 for more
information.
Words: 2
Cycles: 2 (3)
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
(src)
Process
Data
No
operation
Decode No
operation
No dummy
read
No
operation
Write
register 'f'
(dest)
Example: MOVFF REG1, REG2
Before Instruction
REG1 = 0x33
REG2 = 0x11
After Instruction
REG1 = 0x33,
REG2 = 0x33
MOVLB Move literal to low nibble in BSR
Syntax: [ label ] MOVLB k
Operands: 0 ≤ k ≤ 255
Operation: k → BSR
Status Affected: None
Encoding: 0000 0001 kkkk kkkk
Description: The 8-bit literal 'k' is loaded into
the Bank Select Register (BSR).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'k'
Process
Data
Write
literal 'k' to
BSR
Example: MOVLB 5
Before Instruction
BSR register = 0x02
After Instruction
BSR register = 0x05© 2006 Microchip Technology Inc. DS39564C-page 237
PIC18FXX2
MOVLW Move literal to W
Syntax: [ label ] MOVLW k
Operands: 0 ≤ k ≤ 255
Operation: k → W
Status Affected: None
Encoding: 0000 1110 kkkk kkkk
Description: The eight-bit literal 'k' is loaded
into W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write to W
Example: MOVLW 0x5A
After Instruction
W = 0x5A
MOVWF Move W to f
Syntax: [ label ] MOVWF f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: (W) → f
Status Affected: None
Encoding: 0110 111a ffff ffff
Description: Move data from W to register 'f'.
Location 'f' can be anywhere in the
256 byte bank. If ‘a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: MOVWF REG, 0
Before Instruction
W = 0x4F
REG = 0xFF
After Instruction
W = 0x4F
REG = 0x4FPIC18FXX2
DS39564C-page 238 © 2006 Microchip Technology Inc.
MULLW Multiply Literal with W
Syntax: [ label ] MULLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) x k → PRODH:PRODL
Status Affected: None
Encoding: 0000 1101 kkkk kkkk
Description: An unsigned multiplication is carried
out between the contents of
W and the 8-bit literal 'k'. The
16-bit result is placed in
PRODH:PRODL register pair.
PRODH contains the high byte.
W is unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this operation.
A zero result is possible but
not detected.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write
registers
PRODH:
PRODL
Example: MULLW 0xC4
Before Instruction
W = 0xE2
PRODH = ?
PRODL = ?
After Instruction
W = 0xE2
PRODH = 0xAD
PRODL = 0x08
MULWF Multiply W with f
Syntax: [ label ] MULWF f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: (W) x (f) → PRODH:PRODL
Status Affected: None
Encoding: 0000 001a ffff ffff
Description: An unsigned multiplication is carried
out between the contents of
W and the register file location 'f'.
The 16-bit result is stored in the
PRODH:PRODL register pair.
PRODH contains the high byte.
Both W and 'f' are unchanged.
None of the status flags are
affected.
Note that neither overflow nor
carry is possible in this operation.
A zero result is possible but
not detected. If ‘a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If
‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
registers
PRODH:
PRODL
Example: MULWF REG, 1
Before Instruction
W = 0xC4
REG = 0xB5
PRODH = ?
PRODL = ?
After Instruction
W = 0xC4
REG = 0xB5
PRODH = 0x8A
PRODL = 0x94© 2006 Microchip Technology Inc. DS39564C-page 239
PIC18FXX2
NEGF Negate f
Syntax: [ label ] NEGF f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: ( f ) + 1 → f
Status Affected: N, OV, C, DC, Z
Encoding: 0110 110a ffff ffff
Description: Location ‘f’ is negated using two’s
complement. The result is placed in
the data memory location 'f'. If ’a’ is
0, the Access Bank will be
selected, overriding the BSR value.
If ’a’ = 1, then the bank will be
selected as per the BSR value.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: NEGF REG, 1
Before Instruction
REG = 0011 1010 [0x3A]
After Instruction
REG = 1100 0110 [0xC6]
NOP No Operation
Syntax: [ label ] NOP
Operands: None
Operation: No operation
Status Affected: None
Encoding: 0000
1111
0000
xxxx
0000
xxxx
0000
xxxx
Description: No operation.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
Example:
None.PIC18FXX2
DS39564C-page 240 © 2006 Microchip Technology Inc.
POP Pop Top of Return Stack
Syntax: [ label ] POP
Operands: None
Operation: (TOS) → bit bucket
Status Affected: None
Encoding: 0000 0000 0000 0110
Description: The TOS value is pulled off the
return stack and is discarded. The
TOS value then becomes the previous
value that was pushed onto the
return stack.
This instruction is provided to
enable the user to properly manage
the return stack to incorporate a
software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
POP TOS
value
No
operation
Example: POP
GOTO NEW
Before Instruction
TOS = 0031A2h
Stack (1 level down) = 014332h
After Instruction
TOS = 014332h
PC = NEW
PUSH Push Top of Return Stack
Syntax: [ label ] PUSH
Operands: None
Operation: (PC+2) → TOS
Status Affected: None
Encoding: 0000 0000 0000 0101
Description: The PC+2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows to implement
a software stack by modifying TOS,
and then push it onto the return
stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode PUSH PC+2
onto return
stack
No
operation
No
operation
Example: PUSH
Before Instruction
TOS = 00345Ah
PC = 000124h
After Instruction
PC = 000126h
TOS = 000126h
Stack (1 level down) = 00345Ah© 2006 Microchip Technology Inc. DS39564C-page 241
PIC18FXX2
RCALL Relative Call
Syntax: [ label ] RCALL n
Operands: -1024 ≤ n ≤ 1023
Operation: (PC) + 2 → TOS,
(PC) + 2 + 2n → PC
Status Affected: None
Encoding: 1101 1nnn nnnn nnnn
Description: Subroutine call with a jump up to
1K from the current location. First,
return address (PC+2) is pushed
onto the stack. Then, add the 2’s
complement number ’2n’ to the PC.
Since the PC will have incremented
to fetch the next instruction, the
new address will be PC+2+2n.
This instruction is a two-cycle
instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
'n'
Push PC to
stack
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE RCALL Jump
Before Instruction
PC = Address (HERE)
After Instruction
PC = Address (Jump)
TOS = Address (HERE+2)
RESET Reset
Syntax: [ label ] RESET
Operands: None
Operation: Reset all registers and flags that
are affected by a MCLR Reset.
Status Affected: All
Encoding: 0000 0000 1111 1111
Description: This instruction provides a way to
execute a MCLR Reset in software.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Start
reset
No
operation
No
operation
Example: RESET
After Instruction
Registers = Reset Value
Flags* = Reset ValuePIC18FXX2
DS39564C-page 242 © 2006 Microchip Technology Inc.
RETFIE Return from Interrupt
Syntax: [ label ] RETFIE [s]
Operands: s ∈ [0,1]
Operation: (TOS) → PC,
1 → GIE/GIEH or PEIE/GIEL,
if s = 1
(WS) → W,
(STATUSS) → STATUS,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged.
Status Affected: GIE/GIEH, PEIE/GIEL.
Encoding: 0000 0000 0001 000s
Description: Return from Interrupt. Stack is
popped and Top-of-Stack (TOS) is
loaded into the PC. Interrupts are
enabled by setting either the high
or low priority global interrupt
enable bit. If ‘s’ = 1, the contents of
the shadow registers WS,
STATUSS and BSRS are loaded
into their corresponding registers,
W, STATUS and BSR. If ‘s’ = 0, no
update of these registers occurs
(default).
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
pop PC from
stack
Set GIEH or
GIEL
No
operation
No
operation
No
operation
No
operation
Example: RETFIE 1
After Interrupt
PC = TOS
W = WS
BSR = BSRS
STATUS = STATUSS
GIE/GIEH, PEIE/GIEL = 1
RETLW Return Literal to W
Syntax: [ label ] RETLW k
Operands: 0 ≤ k ≤ 255
Operation: k → W,
(TOS) → PC,
PCLATU, PCLATH are unchanged
Status Affected: None
Encoding: 0000 1100 kkkk kkkk
Description: W is loaded with the eight-bit literal
'k'. The program counter is loaded
from the top of the stack (the return
address). The high address latch
(PCLATH) remains unchanged.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
pop PC from
stack, Write
to W
No
operation
No
operation
No
operation
No
operation
Example:
CALL TABLE ; W contains table
; offset value
; W now has
; table value
:
TABLE
ADDWF PCL ; W = offset
RETLW k0 ; Begin table
RETLW k1 ;
:
:
RETLW kn ; End of table
Before Instruction
W = 0x07
After Instruction
W = value of kn© 2006 Microchip Technology Inc. DS39564C-page 243
PIC18FXX2
RETURN Return from Subroutine
Syntax: [ label ] RETURN [s]
Operands: s ∈ [0,1]
Operation: (TOS) → PC,
if s = 1
(WS) → W,
(STATUSS) → STATUS,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged
Status Affected: None
Encoding: 0000 0000 0001 001s
Description: Return from subroutine. The stack
is popped and the top of the stack
(TOS) is loaded into the program
counter. If ‘s’= 1, the contents of the
shadow registers WS, STATUSS
and BSRS are loaded into their corresponding
registers, W, STATUS
and BSR. If ‘s’ = 0, no update of
these registers occurs (default).
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
pop PC from
stack
No
operation
No
operation
No
operation
No
operation
Example: RETURN
After Interrupt
PC = TOS
RLCF Rotate Left f through Carry
Syntax: [ label ] RLCF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) → dest,
(f<7>) → C,
(C) → dest<0>
Status Affected: C, N, Z
Encoding: 0011 01da ffff ffff
Description: The contents of register 'f' are
rotated one bit to the left through
the Carry Flag. If 'd' is 0, the result
is placed in W. If 'd' is 1, the result
is stored back in register 'f'
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: RLCF REG, 0, 0
Before Instruction
REG = 1110 0110
C =0
After Instruction
REG = 1110 0110
W = 1100 1100
C =1
C register fPIC18FXX2
DS39564C-page 244 © 2006 Microchip Technology Inc.
RLNCF Rotate Left f (no carry)
Syntax: [ label ] RLNCF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) → dest,
(f<7>) → dest<0>
Status Affected: N, Z
Encoding: 0100 01da ffff ffff
Description: The contents of register 'f' are
rotated one bit to the left. If 'd' is 0,
the result is placed in W. If 'd' is 1,
the result is stored back in register
'f' (default). If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: RLNCF REG, 1, 0
Before Instruction
REG = 1010 1011
After Instruction
REG = 0101 0111
register f
RRCF Rotate Right f through Carry
Syntax: [ label ] RRCF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) → dest,
(f<0>) → C,
(C) → dest<7>
Status Affected: C, N, Z
Encoding: 0011 00da ffff ffff
Description: The contents of register 'f' are
rotated one bit to the right through
the Carry Flag. If 'd' is 0, the result
is placed in W. If 'd' is 1, the result
is placed back in register 'f'
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: RRCF REG, 0, 0
Before Instruction
REG = 1110 0110
C =0
After Instruction
REG = 1110 0110
W = 0111 0011
C =0
C register f© 2006 Microchip Technology Inc. DS39564C-page 245
PIC18FXX2
RRNCF Rotate Right f (no carry)
Syntax: [ label ] RRNCF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) → dest,
(f<0>) → dest<7>
Status Affected: N, Z
Encoding: 0100 00da ffff ffff
Description: The contents of register 'f' are
rotated one bit to the right. If 'd' is 0,
the result is placed in W. If 'd' is 1,
the result is placed back in register
'f' (default). If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example 1: RRNCF REG, 1, 0
Before Instruction
REG = 1101 0111
After Instruction
REG = 1110 1011
Example 2: RRNCF REG, 0, 0
Before Instruction
W =?
REG = 1101 0111
After Instruction
W = 1110 1011
REG = 1101 0111
register f
SETF Set f
Syntax: [ label ] SETF f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: FFh → f
Status Affected: None
Encoding: 0110 100a ffff ffff
Description: The contents of the specified register
are set to FFh. If ’a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ’a’ is 1, then
the bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write
register 'f'
Example: SETF REG,1
Before Instruction
REG = 0x5A
After Instruction
REG = 0xFFPIC18FXX2
DS39564C-page 246 © 2006 Microchip Technology Inc.
SLEEP Enter SLEEP mode
Syntax: [ label ] SLEEP
Operands: None
Operation: 00h → WDT,
0 → WDT postscaler,
1 → TO,
0 → PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0011
Description: The power-down status bit (PD) is
cleared. The time-out status bit
(TO) is set. Watchdog Timer and
its postscaler are cleared.
The processor is put into SLEEP
mode with the oscillator stopped.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
Go to
sleep
Example: SLEEP
Before Instruction
TO = ?
PD = ?
After Instruction
TO = 1 †
PD = 0
† If WDT causes wake-up, this bit is cleared.
SUBFWB Subtract f from W with borrow
Syntax: [ label ] SUBFWB f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) – (f) – (C) → dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 01da ffff ffff
Description: Subtract register 'f' and carry flag
(borrow) from W (2’s complement
method). If 'd' is 0, the result is
stored in W. If 'd' is 1, the result is
stored in register 'f' (default). If ’a’ is
0, the Access Bank will be selected,
overriding the BSR value. If ’a’ is 1,
then the bank will be selected as
per the BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example 1: SUBFWB REG, 1, 0
Before Instruction
REG = 3
W =2
C =1
After Instruction
REG = FF
W =2
C =0
Z =0
N = 1 ; result is negative
Example 2: SUBFWB REG, 0, 0
Before Instruction
REG = 2
W =5
C =1
After Instruction
REG = 2
W =3
C =1
Z =0
N = 0 ; result is positive
Example 3: SUBFWB REG, 1, 0
Before Instruction
REG = 1
W =2
C =0
After Instruction
REG = 0
W =2
C =1
Z = 1 ; result is zero
N =0© 2006 Microchip Technology Inc. DS39564C-page 247
PIC18FXX2
SUBLW Subtract W from literal
Syntax: [ label ] SUBLW k
Operands: 0 ≤ k ≤ 255
Operation: k – (W) → W
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1000 kkkk kkkk
Description: W is subtracted from the eight-bit
literal 'k'. The result is placed
in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write to W
Example 1: SUBLW 0x02
Before Instruction
W =1
C =?
After Instruction
W =1
C = 1 ; result is positive
Z =0
N =0
Example 2: SUBLW 0x02
Before Instruction
W =2
C =?
After Instruction
W =0
C = 1 ; result is zero
Z =1
N =0
Example 3: SUBLW 0x02
Before Instruction
W =3
C =?
After Instruction
W = FF ; (2’s complement)
C = 0 ; result is negative
Z =0
N =1
SUBWF Subtract W from f
Syntax: [ label ] SUBWF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) – (W) → dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 11da ffff ffff
Description: Subtract W from register 'f' (2’s
complement method). If 'd' is 0,
the result is stored in W. If 'd' is 1,
the result is stored back in register
'f' (default). If ’a’ is 0, the
Access Bank will be selected,
overriding the BSR value. If ’a’ is
1, then the bank will be selected
as per the BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example 1: SUBWF REG, 1, 0
Before Instruction
REG = 3
W =2
C =?
After Instruction
REG = 1
W =2
C = 1 ; result is positive
Z =0
N =0
Example 2: SUBWF REG, 0, 0
Before Instruction
REG = 2
W =2
C =?
After Instruction
REG = 2
W =0
C = 1 ; result is zero
Z =1
N =0
Example 3: SUBWF REG, 1, 0
Before Instruction
REG = 1
W =2
C =?
After Instruction
REG = FFh ;(2’s complement)
W =2
C = 0 ; result is negative
Z =0
N =1PIC18FXX2
DS39564C-page 248 © 2006 Microchip Technology Inc.
SUBWFB Subtract W from f with Borrow
Syntax: [ label ] SUBWFB f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f) – (W) – (C) → dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 10da ffff ffff
Description: Subtract W and the carry flag (borrow)
from register 'f' (2’s complement
method). If 'd' is 0, the result is stored
in W. If 'd' is 1, the result is stored
back in register 'f' (default). If ’a’ is 0,
the Access Bank will be selected,
overriding the BSR value. If ’a’ is 1,
then the bank will be selected as per
the BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example 1: SUBWFB REG, 1, 0
Before Instruction
REG = 0x19 (0001 1001)
W = 0x0D (0000 1101)
C =1
After Instruction
REG = 0x0C (0000 1011)
W = 0x0D (0000 1101)
C =1
Z =0
N = 0 ; result is positive
Example 2: SUBWFB REG, 0, 0
Before Instruction
REG = 0x1B (0001 1011)
W = 0x1A (0001 1010)
C =0
After Instruction
REG = 0x1B (0001 1011)
W = 0x00
C =1
Z = 1 ; result is zero
N =0
Example 3: SUBWFB REG, 1, 0
Before Instruction
REG = 0x03 (0000 0011)
W = 0x0E (0000 1101)
C =1
After Instruction
REG = 0xF5 (1111 0100)
; [2’s comp]
W = 0x0E (0000 1101)
C =0
Z =0
N = 1 ; result is negative
SWAPF Swap f
Syntax: [ label ] SWAPF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (f<3:0>) → dest<7:4>,
(f<7:4>) → dest<3:0>
Status Affected: None
Encoding: 0011 10da ffff ffff
Description: The upper and lower nibbles of register
'f' are exchanged. If 'd' is 0, the
result is placed in W. If 'd' is 1, the
result is placed in register 'f'
(default). If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: SWAPF REG, 1, 0
Before Instruction
REG = 0x53
After Instruction
REG = 0x35© 2006 Microchip Technology Inc. DS39564C-page 249
PIC18FXX2
TBLRD Table Read
Syntax: [ label ] TBLRD ( *; *+; *-; +*)
Operands: None
Operation: if TBLRD *,
(Prog Mem (TBLPTR)) → TABLAT;
TBLPTR - No Change;
if TBLRD *+,
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) +1 → TBLPTR;
if TBLRD *-,
(Prog Mem (TBLPTR)) → TABLAT;
(TBLPTR) -1 → TBLPTR;
if TBLRD +*,
(TBLPTR) +1 → TBLPTR;
(Prog Mem (TBLPTR)) → TABLAT;
Status Affected:None
Encoding: 0000 0000 0000 10nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction is used to read the contents
of Program Memory (P.M.). To
address the program memory, a pointer
called Table Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2 Mbyte address range.
TBLPTR[0] = 0: Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1: Most Significant
Byte of Program
Memory Word
The TBLRD instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No operation
(Read Program
Memory)
No
operation
No operation
(Write TABLAT)
TBLRD Table Read (cont’d)
Example1: TBLRD *+ ;
Before Instruction
TABLAT = 0x55
TBLPTR = 0x00A356
MEMORY(0x00A356) = 0x34
After Instruction
TABLAT = 0x34
TBLPTR = 0x00A357
Example2: TBLRD +* ;
Before Instruction
TABLAT = 0xAA
TBLPTR = 0x01A357
MEMORY(0x01A357) = 0x12
MEMORY(0x01A358) = 0x34
After Instruction
TABLAT = 0x34
TBLPTR = 0x01A358PIC18FXX2
DS39564C-page 250 © 2006 Microchip Technology Inc.
TBLWT Table Write
Syntax: [ label ] TBLWT ( *; *+; *-; +*)
Operands: None
Operation: if TBLWT*,
(TABLAT) → Holding Register;
TBLPTR - No Change;
if TBLWT*+,
(TABLAT) → Holding Register;
(TBLPTR) +1 → TBLPTR;
if TBLWT*-,
(TABLAT) → Holding Register;
(TBLPTR) -1 → TBLPTR;
if TBLWT+*,
(TBLPTR) +1 → TBLPTR;
(TABLAT) → Holding Register;
Status Affected: None
Encoding: 0000 0000 0000 11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction uses the 3 LSbs of the
TBLPTR to determine which of the 8
holding registers the TABLAT data is
written to. The 8 holding registers are
used to program the contents of Program
Memory (P.M.). See Section 5.0
for information on writing to FLASH
memory.
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2 MBtye address
range. The LSb of the TBLPTR selects
which byte of the program memory
location to access.
TBLPTR[0] = 0: Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1: Most Significant
Byte of Program
Memory Word
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
(Write to Holding
Register or Memory)
TBLWT Table Write (Continued)
Example1: TBLWT *+;
Before Instruction
TABLAT = 0x55
TBLPTR = 0x00A356
HOLDING REGISTER
(0x00A356) = 0xFF
After Instructions (table write completion)
TABLAT = 0x55
TBLPTR = 0x00A357
HOLDING REGISTER
(0x00A356) = 0x55
Example 2: TBLWT +*;
Before Instruction
TABLAT = 0x34
TBLPTR = 0x01389A
HOLDING REGISTER
(0x01389A) = 0xFF
HOLDING REGISTER
(0x01389B) = 0xFF
After Instruction (table write completion)
TABLAT = 0x34
TBLPTR = 0x01389B
HOLDING REGISTER
(0x01389A) = 0xFF
HOLDING REGISTER
(0x01389B) = 0x34
© 2006 Microchip Technology Inc. DS39564C-page 251
PIC18FXX2
TSTFSZ Test f, skip if 0
Syntax: [ label ] TSTFSZ f [,a]
Operands: 0 ≤ f ≤ 255
a ∈ [0,1]
Operation: skip if f = 0
Status Affected: None
Encoding: 0110 011a ffff ffff
Description: If 'f' = 0, the next instruction,
fetched during the current instruction
execution, is discarded and a
NOP is executed, making this a twocycle
instruction. If ’a’ is 0, the
Access Bank will be selected, overriding
the BSR value. If ’a’ is 1,
then the bank will be selected as
per the BSR value (default).
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE TSTFSZ CNT, 1
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
If CNT = 0x00,
PC = Address (ZERO)
If CNT ≠ 0x00,
PC = Address (NZERO)
XORLW Exclusive OR literal with W
Syntax: [ label ] XORLW k
Operands: 0 ≤ k ≤ 255
Operation: (W) .XOR. k → W
Status Affected: N, Z
Encoding: 0000 1010 kkkk kkkk
Description: The contents of W are XORed
with the 8-bit literal 'k'. The result
is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
Write to W
Example: XORLW 0xAF
Before Instruction
W = 0xB5
After Instruction
W = 0x1APIC18FXX2
DS39564C-page 252 © 2006 Microchip Technology Inc.
XORWF Exclusive OR W with f
Syntax: [ label ] XORWF f [,d [,a]
Operands: 0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation: (W) .XOR. (f) → dest
Status Affected: N, Z
Encoding: 0001 10da ffff ffff
Description: Exclusive OR the contents of W
with register 'f'. If 'd' is 0, the result
is stored in W. If 'd' is 1, the result is
stored back in the register 'f'
(default). If ‘a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Process
Data
Write to
destination
Example: XORWF REG, 1, 0
Before Instruction
REG = 0xAF
W = 0xB5
After Instruction
REG = 0x1A
W = 0xB5© 2006 Microchip Technology Inc. DS39564C-page 253
PIC18FXX2
21.0 DEVELOPMENT SUPPORT
The PICmicro® microcontrollers are supported with a
full range of hardware and software development tools:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
- MPLAB C17 and MPLAB C18 C Compilers
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
• Simulators
- MPLAB SIM Software Simulator
• Emulators
- MPLAB ICE 2000 In-Circuit Emulator
- ICEPIC™ In-Circuit Emulator
• In-Circuit Debugger
- MPLAB ICD
• Device Programmers
- PRO MATE® II Universal Device Programmer
- PICSTART® Plus Entry-Level Development
Programmer
• Low Cost Demonstration Boards
- PICDEMTM 1 Demonstration Board
- PICDEM 2 Demonstration Board
- PICDEM 3 Demonstration Board
- PICDEM 17 Demonstration Board
- KEELOQ® Demonstration Board
21.1 MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8-bit microcontroller
market. The MPLAB IDE is a Windows® based
application that contains:
• An interface to debugging tools
- simulator
- programmer (sold separately)
- emulator (sold separately)
- in-circuit debugger (sold separately)
• A full-featured editor
• A project manager
• Customizable toolbar and key mapping
• A status bar
• On-line help
The MPLAB IDE allows you to:
• Edit your source files (either assembly or ‘C’)
• One touch assemble (or compile) and download
to PICmicro emulator and simulator tools (automatically
updates all project information)
• Debug using:
- source files
- absolute listing file
- machine code
The ability to use MPLAB IDE with multiple debugging
tools allows users to easily switch from the costeffective
simulator to a full-featured emulator with
minimal retraining.
21.2 MPASM Assembler
The MPASM assembler is a full-featured universal
macro assembler for all PICmicro MCU’s.
The MPASM assembler has a command line interface
and a Windows shell. It can be used as a stand-alone
application on a Windows 3.x or greater system, or it
can be used through MPLAB IDE. The MPASM assembler
generates relocatable object files for the MPLINK
object linker, Intel® standard HEX files, MAP files to
detail memory usage and symbol reference, an absolute
LST file that contains source lines and generated
machine code, and a COD file for debugging.
The MPASM assembler features include:
• Integration into MPLAB IDE projects.
• User-defined macros to streamline assembly
code.
• Conditional assembly for multi-purpose source
files.
• Directives that allow complete control over the
assembly process.
21.3 MPLAB C17 and MPLAB C18
C Compilers
The MPLAB C17 and MPLAB C18 Code Development
Systems are complete ANSI ‘C’ compilers for
Microchip’s PIC17CXXX and PIC18CXXX family of
microcontrollers, respectively. These compilers provide
powerful integration capabilities and ease of use not
found with other compilers.
For easier source level debugging, the compilers provide
symbol information that is compatible with the
MPLAB IDE memory display.PIC18FXX2
DS39564C-page 254 © 2006 Microchip Technology Inc.
21.4 MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK object linker combines relocatable
objects created by the MPASM assembler and the
MPLAB C17 and MPLAB C18 C compilers. It can also
link relocatable objects from pre-compiled libraries,
using directives from a linker script.
The MPLIB object librarian is a librarian for precompiled
code to be used with the MPLINK object
linker. When a routine from a library is called from
another source file, only the modules that contain that
routine will be linked in with the application. This allows
large libraries to be used efficiently in many different
applications. The MPLIB object librarian manages the
creation and modification of library files.
The MPLINK object linker features include:
• Integration with MPASM assembler and MPLAB
C17 and MPLAB C18 C compilers.
• Allows all memory areas to be defined as sections
to provide link-time flexibility.
The MPLIB object librarian features include:
• Easier linking because single libraries can be
included instead of many smaller files.
• Helps keep code maintainable by grouping
related modules together.
• Allows libraries to be created and modules to be
added, listed, replaced, deleted or extracted.
21.5 MPLAB SIM Software Simulator
The MPLAB SIM software simulator allows code development
in a PC-hosted environment by simulating the
PICmicro series microcontrollers on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a file, or user-defined key press, to any of the pins. The
execution can be performed in single step, execute
until break, or trace mode.
The MPLAB SIM simulator fully supports symbolic debugging
using the MPLAB C17 and the MPLAB C18 C compilers
and the MPASM assembler. The software simulator
offers the flexibility to develop and debug code outside of
the laboratory environment, making it an excellent multiproject
software development tool.
21.6 MPLAB ICE High Performance
Universal In-Circuit Emulator with
MPLAB IDE
The MPLAB ICE universal in-circuit emulator is intended
to provide the product development engineer with a
complete microcontroller design tool set for PICmicro
microcontrollers (MCUs). Software control of the
MPLAB ICE in-circuit emulator is provided by the
MPLAB Integrated Development Environment (IDE),
which allows editing, building, downloading and source
debugging from a single environment.
The MPLAB ICE 2000 is a full-featured emulator system
with enhanced trace, trigger and data monitoring
features. Interchangeable processor modules allow the
system to be easily reconfigured for emulation of different
processors. The universal architecture of the
MPLAB ICE in-circuit emulator allows expansion to
support new PICmicro microcontrollers.
The MPLAB ICE in-circuit emulator system has been
designed as a real-time emulation system, with
advanced features that are generally found on more
expensive development tools. The PC platform and
Microsoft® Windows environment were chosen to best
make these features available to you, the end user.
21.7 ICEPIC In-Circuit Emulator
The ICEPIC low cost, in-circuit emulator is a solution
for the Microchip Technology PIC16C5X, PIC16C6X,
PIC16C7X and PIC16CXXX families of 8-bit OneTime-Programmable
(OTP) microcontrollers. The modular
system can support different subsets of PIC16C5X
or PIC16CXXX products through the use of interchangeable
personality modules, or daughter boards.
The emulator is capable of emulating without target
application circuitry being present.© 2006 Microchip Technology Inc. DS39564C-page 255
PIC18FXX2
21.8 MPLAB ICD In-Circuit Debugger
Microchip's In-Circuit Debugger, MPLAB ICD, is a powerful,
low cost, run-time development tool. This tool is
based on the FLASH PICmicro MCUs and can be used
to develop for this and other PICmicro microcontrollers.
The MPLAB ICD utilizes the in-circuit debugging capability
built into the FLASH devices. This feature, along
with Microchip's In-Circuit Serial ProgrammingTM protocol,
offers cost-effective in-circuit FLASH debugging
from the graphical user interface of the MPLAB
Integrated Development Environment. This enables a
designer to develop and debug source code by watching
variables, single-stepping and setting break points.
Running at full speed enables testing hardware in realtime.
21.9 PRO MATE II Universal Device
Programmer
The PRO MATE II universal device programmer is a
full-featured programmer, capable of operating in
stand-alone mode, as well as PC-hosted mode. The
PRO MATE II device programmer is CE compliant.
The PRO MATE II device programmer has programmable
VDD and VPP supplies, which allow it to verify
programmed memory at VDD min and VDD max for maximum
reliability. It has an LCD display for instructions
and error messages, keys to enter commands and a
modular detachable socket assembly to support various
package types. In stand-alone mode, the PRO MATE II
device programmer can read, verify, or program
PICmicro devices. It can also set code protection in this
mode.
21.10 PICSTART Plus Entry Level
Development Programmer
The PICSTART Plus development programmer is an
easy-to-use, low cost, prototype programmer. It connects
to the PC via a COM (RS-232) port. MPLAB
Integrated Development Environment software makes
using the programmer simple and efficient.
The PICSTART Plus development programmer supports
all PICmicro devices with up to 40 pins. Larger pin
count devices, such as the PIC16C92X and
PIC17C76X, may be supported with an adapter socket.
The PICSTART Plus development programmer is CE
compliant.
21.11 PICDEM 1 Low Cost PICmicro
Demonstration Board
The PICDEM 1 demonstration board is a simple board
which demonstrates the capabilities of several of
Microchip’s microcontrollers. The microcontrollers supported
are: PIC16C5X (PIC16C54 to PIC16C58A),
PIC16C61, PIC16C62X, PIC16C71, PIC16C8X,
PIC17C42, PIC17C43 and PIC17C44. All necessary
hardware and software is included to run basic demo
programs. The user can program the sample microcontrollers
provided with the PICDEM 1 demonstration
board on a PRO MATE II device programmer, or a
PICSTART Plus development programmer, and easily
test firmware. The user can also connect the
PICDEM 1 demonstration board to the MPLAB ICE incircuit
emulator and download the firmware to the emulator
for testing. A prototype area is available for the
user to build some additional hardware and connect it
to the microcontroller socket(s). Some of the features
include an RS-232 interface, a potentiometer for simulated
analog input, push button switches and eight
LEDs connected to PORTB.
21.12 PICDEM 2 Low Cost PIC16CXX
Demonstration Board
The PICDEM 2 demonstration board is a simple demonstration
board that supports the PIC16C62,
PIC16C64, PIC16C65, PIC16C73 and PIC16C74
microcontrollers. All the necessary hardware and software
is included to run the basic demonstration programs.
The user can program the sample
microcontrollers provided with the PICDEM 2 demonstration
board on a PRO MATE II device programmer,
or a PICSTART Plus development programmer, and
easily test firmware. The MPLAB ICE in-circuit emulator
may also be used with the PICDEM 2 demonstration
board to test firmware. A prototype area has been provided
to the user for adding additional hardware and
connecting it to the microcontroller socket(s). Some of
the features include a RS-232 interface, push button
switches, a potentiometer for simulated analog input, a
serial EEPROM to demonstrate usage of the I2CTM bus
and separate headers for connection to an LCD
module and a keypad.PIC18FXX2
DS39564C-page 256 © 2006 Microchip Technology Inc.
21.13 PICDEM 3 Low Cost PIC16CXXX
Demonstration Board
The PICDEM 3 demonstration board is a simple demonstration
board that supports the PIC16C923 and
PIC16C924 in the PLCC package. It will also support
future 44-pin PLCC microcontrollers with an LCD Module.
All the necessary hardware and software is
included to run the basic demonstration programs. The
user can program the sample microcontrollers provided
with the PICDEM 3 demonstration board on a
PRO MATE II device programmer, or a PICSTART Plus
development programmer with an adapter socket, and
easily test firmware. The MPLAB ICE in-circuit emulator
may also be used with the PICDEM 3 demonstration
board to test firmware. A prototype area has been provided
to the user for adding hardware and connecting it
to the microcontroller socket(s). Some of the features
include a RS-232 interface, push button switches, a
potentiometer for simulated analog input, a thermistor
and separate headers for connection to an external
LCD module and a keypad. Also provided on the
PICDEM 3 demonstration board is a LCD panel, with 4
commons and 12 segments, that is capable of displaying
time, temperature and day of the week. The
PICDEM 3 demonstration board provides an additional
RS-232 interface and Windows software for showing
the demultiplexed LCD signals on a PC. A simple serial
interface allows the user to construct a hardware
demultiplexer for the LCD signals.
21.14 PICDEM 17 Demonstration Board
The PICDEM 17 demonstration board is an evaluation
board that demonstrates the capabilities of several
Microchip microcontrollers, including PIC17C752,
PIC17C756A, PIC17C762 and PIC17C766. All necessary
hardware is included to run basic demo programs,
which are supplied on a 3.5-inch disk. A programmed
sample is included and the user may erase it and
program it with the other sample programs using the
PRO MATE II device programmer, or the PICSTART
Plus development programmer, and easily debug and
test the sample code. In addition, the PICDEM 17 demonstration
board supports downloading of programs to
and executing out of external FLASH memory on board.
The PICDEM 17 demonstration board is also usable
with the MPLAB ICE in-circuit emulator, or the
PICMASTER emulator and all of the sample programs
can be run and modified using either emulator. Additionally,
a generous prototype area is available for user
hardware.
21.15 KEELOQ Evaluation and
Programming Tools
KEELOQ evaluation and programming tools support
Microchip’s HCS Secure Data Products. The HCS evaluation
kit includes a LCD display to show changing
codes, a decoder to decode transmissions and a
programming interface to program test transmitters.© 2006 Microchip Technology Inc. DS39564C-page 257
PIC18FXX2
TABLE 21-1: DEVELOPMENT TOOLS FROM MICROCHIP
PIC12CXXX
PIC14000
PIC16C5X
PIC16C6X
PIC16CXXX
PIC16F62X
PIC16C7X
PIC16C7XX
PIC16C8X/
PIC16F8X
PIC16F8XX
PIC16C9XX
PIC17C4X
PIC17C7XX
PIC18CXX2
PIC18FXXX
24CXX/
25CXX/
93CXX
HCSXXX
MCRFXXX
MCP2510
Software ToolsMPLAB® Integrated Development Environment !!! ! ! ! ! ! ! ! !! ! ! ! MPLAB® C17 C Compiler ! ! MPLAB® C18 C Compiler ! ! MPASMTM Assembler/ MPLINKTM Object Linker !!! ! ! ! ! ! ! ! !! ! ! ! ! !
EmulatorsMPLAB® ICE In-Circuit Emulator !!! ! !!** ! ! ! ! !! ! ! ! ICEPICTM In-Circuit Emulator ! !! ! ! ! ! !
Debugger MPLAB® ICD In-Circuit Debugger
!* !* ! !
ProgrammersPICSTART® Plus Entry Level Development Programmer !!! ! !!** ! ! ! ! !! ! ! ! PRO MATE® II Universal Device Programmer !!! ! !!** ! ! ! ! !! ! ! ! ! !
Demo Boards and Eval Kits
PICDEMTM 1 Demonstration
Board !!!† ! !
PICDEMTM 2 Demonstration
Board
!† !† ! !
PICDEMTM 3 Demonstration
Board
!
PICDEMTM 14A Demonstration
Board
!
PICDEMTM 17 Demonstration
Board
!
KEELOQ® Evaluation Kit
!
KEELOQ® Transponder Kit
!
microIDTM Programmer’s Kit
!
125 kHz microIDTM
Developer’s Kit
!
125 kHz Anticollision microIDTM
Developer’s Kit
!
13.56 MHz Anticollision
microIDTM Developer’s Kit
!
MCP2510 CAN Developer’s Kit
!
* Contact the Microchip Technology Inc. web site at www.microchip.com for information on how to use the MPLAB® ICD In-Circuit Debugger (DV164001) with PIC16C62, 63, 64, 65, 72, 73, 74, 76, 77.
** Contact Microchip Technology Inc. for availability date.
† Development tool is available on select devices.PIC18FXX2
DS39564C-page 258 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 259
PIC18FXX2
22.0 ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings (†)
Ambient temperature under bias.............................................................................................................-55°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) ......................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +7.5V
Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V
Voltage on RA4 with respect to Vss............................................................................................................... 0V to +8.5V
Total power dissipation (Note 1) ...............................................................................................................................1.0W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD)...................................................................................................................... ±20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) .............................................................................................................. ±20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................25 mA
Maximum current sunk by PORTA, PORTB, and PORTE (Note 3) (combined)...................................................200 mA
Maximum current sourced by PORTA, PORTB, and PORTE (Note 3) (combined)..............................................200 mA
Maximum current sunk by PORTC and PORTD (Note 3) (combined)..................................................................200 mA
Maximum current sourced by PORTC and PORTD (Note 3) (combined).............................................................200 mA
Note 1: Power dissipation is calculated as follows:
Pdis = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)
2: Voltage spikes below VSS at the MCLR/VPP pin, inducing currents greater than 80 mA, may cause latchup.
Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR/VPP pin, rather
than pulling this pin directly to VSS.
3: PORTD and PORTE not available on the PIC18F2X2 devices.
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.PIC18FXX2
DS39564C-page 260 © 2006 Microchip Technology Inc.
FIGURE 22-1: PIC18FXX2 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
FIGURE 22-2: PIC18LFXX2 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
Frequency
Voltage
6.0V
5.5V
4.5V
4.0V
2.0V
40 MHz
5.0V
3.5V
3.0V
2.5V
PIC18FXXX
4.2V
Frequency
Voltage
6.0V
5.5V
4.5V
4.0V
2.0V
40 MHz
5.0V
3.5V
3.0V
2.5V
PIC18LFXXX
FMAX = (16.36 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz
Note: VDDAPPMIN is the minimum voltage of the PICmicro® device in the application.
4 MHz
4.2V© 2006 Microchip Technology Inc. DS39564C-page 261
PIC18FXX2
22.1 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial)
PIC18LFXX2
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
PIC18FXX2
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Typ Max Units Conditions
VDD Supply Voltage
D001 PIC18LFXX2 2.0 — 5.5 V HS, XT, RC and LP Osc mode
D001 PIC18FXX2 4.2 — 5.5 V
D002 VDR RAM Data Retention
Voltage(1)
1.5 — — V
D003 VPOR VDD Start Voltage
to ensure internal
Power-on Reset signal
— — 0.7 V See Section 3.1 (Power-on Reset) for details
D004 SVDD VDD Rise Rate
to ensure internal
Power-on Reset signal
0.05 — — V/ms See Section 3.1 (Power-on Reset) for details
VBOR Brown-out Reset Voltage
D005 PIC18LFXX2
BORV1:BORV0 = 11 1.98 — 2.14 V 85°C ≥ T ≥ 25°C
BORV1:BORV0 = 10 2.67 — 2.89 V
BORV1:BORV0 = 01 4.16 — 4.5 V
BORV1:BORV0 = 00 4.45 — 4.83 V
D005 PIC18FXX2
BORV1:BORV0 = 1x N.A. — N.A. V Not in operating voltage range of device
BORV1:BORV0 = 01 4.16 — 4.5 V
BORV1:BORV0 = 00 4.45 — 4.83 V
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in SLEEP mode, or during a device RESET, without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an
impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD
MCLR = VDD; WDT enabled/disabled as specified.
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD or VSS, and all
features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR,...).
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2REXT (mA) with REXT in kOhm.
5: The LVD and BOR modules share a large portion of circuitry. The ΔIBOR and ΔILVD currents are not additive.
Once one of these modules is enabled, the other may also be enabled without further penalty.PIC18FXX2
DS39564C-page 262 © 2006 Microchip Technology Inc.
IDD Supply Current(2,4)
D010 PIC18LFXX2
—
—
—
—
—
—
—
—
—
.5
.5
1.2
.3
.3
1.5
.3
.3
.75
1
1.25
2
1
1
3
1
1
3
mA
mA
mA
mA
mA
mA
mA
mA
mA
XT osc configuration
VDD = 2.0V, +25°C, FOSC = 4 MHz
VDD = 2.0V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
RC osc configuration
VDD = 2.0V, +25°C, FOSC = 4 MHz
VDD = 2.0V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
RCIO osc configuration
VDD = 2.0V, +25°C, FOSC = 4 MHz
VDD = 2.0V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
D010 PIC18FXX2
—
—
—
—
—
—
—
—
—
1.2
1.2
1.2
1.5
1.5
1.6
.75
.75
.8
1.5
2
3
3
4
4
2
3
3
mA
mA
mA
mA
mA
mA
mA
mA
mA
XT osc configuration
VDD = 4.2V, +25°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +125°C, FOSC = 4 MHz
RC osc configuration
VDD = 4.2V, +25°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +125°C, FOSC = 4 MHz
RCIO osc configuration
VDD = 4.2V, +25°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +85°C, FOSC = 4 MHz
VDD = 4.2V, -40°C to +125°C, FOSC = 4 MHz
D010A PIC18LFXX2
— 14 30 μA
LP osc, FOSC = 32 kHz, WDT disabled
VDD = 2.0V, -40°C to +85°C
D010A PIC18FXX2
—
—
40
50
70
100
μA
μA
LP osc, FOSC = 32 kHz, WDT disabled
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
22.1 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial) (Continued)
PIC18LFXX2
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
PIC18FXX2
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Typ Max Units Conditions
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in SLEEP mode, or during a device RESET, without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an
impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD
MCLR = VDD; WDT enabled/disabled as specified.
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD or VSS, and all
features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR,...).
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2REXT (mA) with REXT in kOhm.
5: The LVD and BOR modules share a large portion of circuitry. The ΔIBOR and ΔILVD currents are not additive.
Once one of these modules is enabled, the other may also be enabled without further penalty.© 2006 Microchip Technology Inc. DS39564C-page 263
PIC18FXX2
IDD Supply Current(2,4) (Continued)
D010C PIC18LFXX2
— 10 25 mA
EC, ECIO osc configurations
VDD = 4.2V, -40°C to +85°C
D010C PIC18FXX2
— 10 25 mA
EC, ECIO osc configurations
VDD = 4.2V, -40°C to +125°C
D013 PIC18LFXX2
—
—
—
.6
10
15
2
15
25
mA
mA
mA
HS osc configuration
FOSC = 4 MHz, VDD = 2.0V
FOSC = 25 MHz, VDD = 5.5V
HS + PLL osc configurations
FOSC = 10 MHz, VDD = 5.5V
D013 PIC18FXX2
—
—
10
15
15
25
mA
mA
HS osc configuration
FOSC = 25 MHz, VDD = 5.5V
HS + PLL osc configurations
FOSC = 10 MHz, VDD = 5.5V
D014 PIC18LFXX2
— 15 55 μA
Timer1 osc configuration
FOSC = 32 kHz, VDD = 2.0V
D014 PIC18FXX2
—
—
—
—
200
250
μA
μA
Timer1 osc configuration
FOSC = 32 kHz, VDD = 4.2V, -40°C to +85°C
FOSC = 32 kHz, VDD = 4.2V, -40°C to +125°C
IPD Power-down Current(3)
D020 PIC18LFXX2 —
—
—
.08
.1
3
.9
4
10
μA
μA
μA
VDD = 2.0V, +25°C
VDD = 2.0V, -40°C to +85°C
VDD = 4.2V, -40°C to +85°C
D020
D021B
PIC18FXX2 —
—
—
.1
3
15
.9
10
25
μA
μA
μA
VDD = 4.2V, +25°C
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
22.1 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial) (Continued)
PIC18LFXX2
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
PIC18FXX2
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Typ Max Units Conditions
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in SLEEP mode, or during a device RESET, without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an
impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD
MCLR = VDD; WDT enabled/disabled as specified.
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD or VSS, and all
features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR,...).
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2REXT (mA) with REXT in kOhm.
5: The LVD and BOR modules share a large portion of circuitry. The ΔIBOR and ΔILVD currents are not additive.
Once one of these modules is enabled, the other may also be enabled without further penalty.PIC18FXX2
DS39564C-page 264 © 2006 Microchip Technology Inc.
Module Differential Current
D022 ΔIWDT Watchdog Timer
PIC18LFXX2
—
—
—
.75
2
10
1.5
8
25
μA
μA
μA
VDD = 2.0V, +25°C
VDD = 2.0V, -40°C to +85°C
VDD = 4.2V, -40°C to +85°C
D022 Watchdog Timer
PIC18FXX2
—
—
—
7
10
25
15
25
40
μA
μA
μA
VDD = 4.2V, +25°C
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
D022A ΔIBOR Brown-out Reset(5)
PIC18LFXX2
—
—
—
29
29
33
35
45
50
μA
μA
μA
VDD = 2.0V, +25°C
VDD = 2.0V, -40°C to +85°C
VDD = 4.2V, -40°C to +85°C
D022A Brown-out Reset(5)
PIC18FXX2
—
—
—
36
36
36
40
50
65
μA
μA
μA
VDD = 4.2V, +25°C
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
D022B ΔILVD Low Voltage Detect(5)
PIC18LFXX2
—
—
—
29
29
33
35
45
50
μA
μA
μA
VDD = 2.0V, +25°C
VDD = 2.0V, -40°C to +85°C
VDD = 4.2V, -40°C to +85°C
D022B Low Voltage Detect(5)
PIC18FXX2
—
—
—
33
33
33
40
50
65
μA
μA
μA
VDD = 4.2V, +25°C
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
D025 ΔITMR1 Timer1 Oscillator
PIC18LFXX2
—
—
—
5.2
5.2
6.5
30
40
50
μA
μA
μA
VDD = 2.0V, +25°C
VDD = 2.0V, -40°C to +85°C
VDD = 4.2V, -40°C to +85°C
D025 Timer1 Oscillator
PIC18FXX2
—
—
—
6.5
6.5
6.5
40
50
65
μA
μA
μA
VDD = 4.2V, +25°C
VDD = 4.2V, -40°C to +85°C
VDD = 4.2V, -40°C to +125°C
22.1 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial) (Continued)
PIC18LFXX2
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
PIC18FXX2
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Typ Max Units Conditions
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in SLEEP mode, or during a device RESET, without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an
impact on the current consumption.
The test conditions for all IDD measurements in active Operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD
MCLR = VDD; WDT enabled/disabled as specified.
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD or VSS, and all
features that add delta current disabled (such as WDT, Timer1 Oscillator, BOR,...).
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be
estimated by the formula Ir = VDD/2REXT (mA) with REXT in kOhm.
5: The LVD and BOR modules share a large portion of circuitry. The ΔIBOR and ΔILVD currents are not additive.
Once one of these modules is enabled, the other may also be enabled without further penalty.© 2006 Microchip Technology Inc. DS39564C-page 265
PIC18FXX2
22.2 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial)
DC CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Max Units Conditions
VIL Input Low Voltage
I/O ports:
D030 with TTL buffer Vss 0.15 VDD V VDD < 4.5V
D030A — 0.8 V 4.5V ≤ VDD ≤ 5.5V
D031 with Schmitt Trigger buffer
RC3 and RC4
Vss
Vss
0.2 VDD
0.3 VDD
V
V
D032 MCLR VSS 0.2 VDD V
D032A OSC1 (in XT, HS and LP modes)
and T1OSI
VSS 0.3 VDD V
D033 OSC1 (in RC and EC mode)(1) VSS 0.2 VDD V
VIH Input High Voltage
I/O ports:
D040 with TTL buffer 0.25 VDD +
0.8V
VDD V VDD < 4.5V
D040A 2.0 VDD V 4.5V ≤ VDD ≤ 5.5V
D041 with Schmitt Trigger buffer
RC3 and RC4
0.8 VDD
0.7 VDD
VDD
VDD
V
V
D042 MCLR, OSC1 (EC mode) 0.8 VDD VDD V
D042A OSC1 (in XT, HS and LP modes)
and T1OSI
0.7 VDD VDD V
D043 OSC1 (RC mode)(1) 0.9 VDD VDD V
IIL Input Leakage Current(2,3)
D060 I/O ports .02 ±1 μA VSS ≤ VPIN ≤ VDD,
Pin at hi-impedance
D061 MCLR — ±1 μA Vss ≤ VPIN ≤ VDD
D063 OSC1 — ±1 μA Vss ≤ VPIN ≤ VDD
IPU Weak Pull-up Current
D070 IPURB PORTB weak pull-up current 50 450 μA VDD = 5V, VPIN = VSS
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PICmicro device be driven with an external clock while in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
4: Parameter is characterized but not tested.PIC18FXX2
DS39564C-page 266 © 2006 Microchip Technology Inc.
VOL Output Low Voltage
D080 I/O ports — 0.6 V IOL = 8.5 mA, VDD = 4.5V,
-40°C to +85°C
D080A — 0.6 V IOL = 7.0 mA, VDD = 4.5V,
-40°C to +125°C
D083 OSC2/CLKO
(RC mode)
— 0.6 V IOL = 1.6 mA, VDD = 4.5V,
-40°C to +85°C
D083A — 0.6 V IOL = 1.2 mA, VDD = 4.5V,
-40°C to +125°C
VOH Output High Voltage(3)
D090 I/O ports VDD – 0.7 — V IOH = -3.0 mA, VDD = 4.5V,
-40°C to +85°C
D090A VDD – 0.7 — V IOH = -2.5 mA, VDD = 4.5V,
-40°C to +125°C
D092 OSC2/CLKO
(RC mode)
VDD – 0.7 — V IOH = -1.3 mA, VDD = 4.5V,
-40°C to +85°C
D092A VDD – 0.7 — V IOH = -1.0 mA, VDD = 4.5V,
-40°C to +125°C
D150 VOD Open Drain High Voltage — 8.5 V RA4 pin
Capacitive Loading Specs
on Output Pins
D100(4) COSC2 OSC2 pin — 15 pF In XT, HS and LP modes
when external clock is used
to drive OSC1
D101 CIO All I/O pins and OSC2
(in RC mode)
— 50 pF To meet the AC Timing
Specifications
D102 CB SCL, SDA — 400 pF In I2C mode
22.2 DC Characteristics: PIC18FXX2 (Industrial, Extended)
PIC18LFXX2 (Industrial) (Continued)
DC CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Max Units Conditions
Note 1: In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PICmicro device be driven with an external clock while in RC mode.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified
levels represent normal operating conditions. Higher leakage current may be measured at different input
voltages.
3: Negative current is defined as current sourced by the pin.
4: Parameter is characterized but not tested.© 2006 Microchip Technology Inc. DS39564C-page 267
PIC18FXX2
FIGURE 22-3: LOW VOLTAGE DETECT CHARACTERISTICS
TABLE 22-1: LOW VOLTAGE DETECT CHARACTERISTICS
VLVD
LVDIF
VDD
(LVDIF set by hardware)
(LVDIF can be
cleared in software)
37
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Symbol Characteristic Min Typ Max Units Conditions
D420 VLVD LVD Voltage on VDD
transition high to
low
LVV = 0001 1.98 2.06 2.14 V T ≥ 25°C
LVV = 0010 2.18 2.27 2.36 V T ≥ 25°C
LVV = 0011 2.37 2.47 2.57 V T ≥ 25°C
LVV = 0100 2.48 2.58 2.68 V
LVV = 0101 2.67 2.78 2.89 V
LVV = 0110 2.77 2.89 3.01 V
LVV = 0111 2.98 3.1 3.22 V
LVV = 1000 3.27 3.41 3.55 V
LVV = 1001 3.47 3.61 3.75 V
LVV = 1010 3.57 3.72 3.87 V
LVV = 1011 3.76 3.92 4.08 V
LVV = 1100 3.96 4.13 4.3 V
LVV = 1101 4.16 4.33 4.5 V
LVV = 1110 4.45 4.64 4.83 VPIC18FXX2
DS39564C-page 268 © 2006 Microchip Technology Inc.
TABLE 22-2: MEMORY PROGRAMMING REQUIREMENTS
DC Characteristics
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No. Sym Characteristic Min Typ† Max Units Conditions
Internal Program Memory
Programming Specifications
D110 VPP Voltage on MCLR/VPP pin 9.00 — 13.25 V
D113 IDDP Supply Current during
Programming
— — 10 mA
Data EEPROM Memory
D120 ED Cell Endurance 100K 1M — E/W -40°C to +85°C
D121 VDRW VDD for Read/Write VMIN — 5.5 V Using EECON to read/write
VMIN = Minimum operating
voltage
D122 TDEW Erase/Write Cycle Time — 4 — ms
D123 TRETD Characteristic Retention 40 — — Year Provided no other
specifications are violated
D124 TREF Number of Total Erase/Write
Cycles before Refresh(1)
1M 10M — E/W -40°C to +85°C
Program FLASH Memory
D130 EP Cell Endurance 10K 100K — E/W -40°C to +85°C
D131 VPR VDD for Read VMIN — 5.5 V VMIN = Minimum operating
voltage
D132 VIE VDD for Block Erase 4.5 — 5.5 V Using ICSP port
D132A VIW VDD for Externally Timed Erase
or Write
4.5 — 5.5 V Using ICSP port
D132B VPEW VDD for Self-timed Write VMIN — 5.5 V VMIN = Minimum operating
voltage
D133 TIE ICSP Block Erase Cycle Time — 4 — ms VDD ≥ 4.5V
D133A TIW ICSP Erase or Write Cycle Time
(externally timed)
1 — — ms VDD ≥ 4.5V
D133A TIW Self-timed Write Cycle Time — 2 — ms
D134 TRETD Characteristic Retention 40 — — Year Provided no other
specifications are violated
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Refer to Section 6.8 for a more detailed discussion on data EEPROM endurance.© 2006 Microchip Technology Inc. DS39564C-page 269
PIC18FXX2
22.3 AC (Timing) Characteristics
22.3.1 TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created
following one of the following formats:
1. TppS2ppS 3. TCC:ST (I2C specifications only)
2. TppS 4. Ts (I2C specifications only)
T
F Frequency T Time
Lowercase letters (pp) and their meanings:
pp
cc CCP1 osc OSC1
ck CLKO rd RD
cs CS rw RD or WR
di SDI sc SCK
do SDO ss SS
dt Data in t0 T0CKI
io I/O port t1 T1CKI
mc MCLR wr WR
Uppercase letters and their meanings:
S
F Fall P Period
H High R Rise
I Invalid (Hi-impedance) V Valid
L Low Z Hi-impedance
I
2C only
AA output access High High
BUF Bus free Low Low
TCC:ST (I2C specifications only)
CC
HD Hold SU Setup
ST
DAT DATA input hold STO STOP condition
STA START conditionPIC18FXX2
DS39564C-page 270 © 2006 Microchip Technology Inc.
22.3.2 TIMING CONDITIONS
The temperature and voltages specified in Table 22-3
apply to all timing specifications unless otherwise
noted. Figure 22-4 specifies the load conditions for the
timing specifications.
TABLE 22-3: TEMPERATURE AND VOLTAGE SPECIFICATIONS - AC
FIGURE 22-4: LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
AC CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Operating voltage VDD range as described in DC spec Section 22.1 and
Section 22.2.
LC parts operate for industrial temperatures only.
VDD/2
CL
RL
Pin
Pin
VSS
VSS
CL
RL = 464Ω
CL = 50 pF for all pins except OSC2/CLKO
and including D and E outputs as ports
Load condition 1 Load condition 2© 2006 Microchip Technology Inc. DS39564C-page 271
PIC18FXX2
22.3.3 TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 22-5: EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
TABLE 22-4: EXTERNAL CLOCK TIMING REQUIREMENTS
OSC1
CLKO
Q4 Q1 Q2 Q3 Q4 Q1
1
2
3 3 4 4
Param.
No. Symbol Characteristic Min Max Units Conditions
1A FOSC External CLKI Frequency(1) DC 40 MHz EC, ECIO, -40°C to +85°C
Oscillator Frequency(1) DC 25 MHz EC, ECIO, +85°C to +125°C
DC 4 MHz RC osc
0.1 4 MHz XT osc
4 25 MHz HS osc
4 10 MHz HS + PLL osc, -40°C to +85°C
4 6.25 MHz HS + PLL osc, +85°C to +125°C
5 200 kHz LP Osc mode
1 TOSC External CLKI Period(1) 25 — ns EC, ECIO, -40°C to +85°C
Oscillator Period(1) 40 — ns EC, ECIO, +85°C to +125°C
250 — ns RC osc
250 10,000 ns XT osc
40 250 ns HS osc
100 250 ns HS + PLL osc, -40°C to +85°C
160 250 ns HS + PLL osc, +85°C to +125°C
25 — μs LP osc
2 TCY Instruction Cycle Time(1) 100 — ns TCY = 4/FOSC, -40°C to +85°C
160 — ns TCY = 4/FOSC, +85°C to +125°C
3 TosL,
TosH
External Clock in (OSC1)
High or Low Time
30 — ns XT osc
2.5 — μs LP osc
10 — ns HS osc
4 TosR,
TosF
External Clock in (OSC1)
Rise or Fall Time
— 20 ns XT osc
— 50 ns LP osc
— 7.5 ns HS osc
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time-base period for all configurations
except PLL. All specified values are based on characterization data for that particular oscillator type under
standard operating conditions with the device executing code. Exceeding these specified limits may result in
an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to
operate at “min.” values with an external clock applied to the OSC1/CLKI pin. When an external clock input
is used, the “max.” cycle time limit is “DC” (no clock) for all devices.PIC18FXX2
DS39564C-page 272 © 2006 Microchip Technology Inc.
TABLE 22-5: PLL CLOCK TIMING SPECIFICATIONS (VDD = 4.2 TO 5.5V)
FIGURE 22-6: CLKO AND I/O TIMING
Param
No. Sym Characteristic Min Typ† Max Units Conditions
— FOSC Oscillator Frequency Range 4 — 10 MHz HS mode only
— FSYS On-chip VCO System Frequency 16 — 40 MHz HS mode only
— trc PLL Start-up Time (Lock Time) — — 2 ms
— ΔCLK CLKO Stability (Jitter) -2 — +2 %
† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note: Refer to Figure 22-4 for load conditions.
OSC1
CLKO
I/O Pin
(input)
I/O Pin
(output)
Q4 Q1 Q2 Q3
10
13
14
17
20, 21
19 18
15
11
12
16
Old Value New Value© 2006 Microchip Technology Inc. DS39564C-page 273
PIC18FXX2
TABLE 22-6: CLKO AND I/O TIMING REQUIREMENTS
FIGURE 22-7: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
Param.
No. Symbol Characteristic Min Typ Max Units Conditions
10 TosH2ckL OSC1↑ to CLKO↓ — 75 200 ns (Note 1)
11 TosH2ckH OSC1↑ to CLKO↑ — 75 200 ns (Note 1)
12 TckR CLKO rise time — 35 100 ns (Note 1)
13 TckF CLKO fall time — 35 100 ns (Note 1)
14 TckL2ioV CLKO↓ to Port out valid — — 0.5 TCY + 20 ns (Note 1)
15 TioV2ckH Port in valid before CLKO ↑ 0.25 TCY + 25 — — ns (Note 1)
16 TckH2ioI Port in hold after CLKO ↑ 0 — — ns (Note 1)
17 TosH2ioV OSC1↑ (Q1 cycle) to Port out valid — 50 150 ns
18 TosH2ioI OSC1↑ (Q2 cycle) to Port
input invalid (I/O in hold time)
PIC18FXXX 100 — — ns
18A PIC18LFXXX 200 — — ns
19 TioV2osH Port input valid to OSC1↑ (I/O in setup time) 0 — — ns
20 TioR Port output rise time PIC18FXXX — 10 25 ns
20A PIC18LFXXX — — 60 ns VDD = 2V
21 TioF Port output fall time PIC18FXXX — 10 25 ns
21A PIC18LFXXX — — 60 ns VDD = 2V
22†† TINP INT pin high or low time TCY — — ns
23†† TRBP RB7:RB4 change INT high or low time TCY — — ns
24†† TRCP RC7:RC4 change INT high or low time 20 ns
†† These parameters are asynchronous events not related to any internal clock edges.
Note 1: Measurements are taken in RC mode, where CLKO output is 4 x TOSC.
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
33
32
30
31
34
I/O Pins
34
Note: Refer to Figure 22-4 for load conditions.PIC18FXX2
DS39564C-page 274 © 2006 Microchip Technology Inc.
FIGURE 22-8: BROWN-OUT RESET TIMING
TABLE 22-7: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
VDD
BVDD
35
VBGAP = 1.2V
VIRVST
Enable Internal Reference Voltage
Internal Reference Voltage stable 36
Typical
Param.
No. Symbol Characteristic Min Typ Max Units Conditions
30 TmcL MCLR Pulse Width (low) 2 — — μs
31 TWDT Watchdog Timer Time-out Period
(No Postscaler)
7 18 33 ms
32 TOST Oscillation Start-up Timer Period 1024 TOSC — 1024 TOSC — TOSC = OSC1 period
33 TPWRT Power up Timer Period 28 72 132 ms
34 TIOZ I/O Hi-impedance from MCLR Low
or Watchdog Timer Reset
—2— μs
35 TBOR Brown-out Reset Pulse Width 200 — — μs VDD ≤ BVDD (see
D005)
36 TIVRST Time for Internal Reference
Voltage to become stable
— 20 500 μs
37 TLVD Low Voltage Detect Pulse Width 200 — — μs VDD ≤ VLVD (see
D420)© 2006 Microchip Technology Inc. DS39564C-page 275
PIC18FXX2
FIGURE 22-9: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
TABLE 22-8: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Note: Refer to Figure 22-4 for load conditions.
46
47
45
48
41
42
40
T0CKI
T1OSO/T1CKI
TMR0 or
TMR1
Param
No. Symbol Characteristic Min Max Units Conditions
40 Tt0H T0CKI High Pulse Width No Prescaler 0.5TCY + 20 — ns
With Prescaler 10 — ns
41 Tt0L T0CKI Low Pulse Width No Prescaler 0.5TCY + 20 — ns
With Prescaler 10 — ns
42 Tt0P T0CKI Period No Prescaler TCY + 10 — ns
With Prescaler Greater of:
20 nS or TCY + 40
N
— ns N = prescale
value
(1, 2, 4,..., 256)
45 Tt1H T1CKI High
Time
Synchronous, no prescaler 0.5TCY + 20 — ns
Synchronous,
with prescaler
PIC18FXXX 10 — ns
PIC18LFXXX 25 — ns
Asynchronous PIC18FXXX 30 — ns
PIC18LFXXX 50 — ns
46 Tt1L T1CKI Low
Time
Synchronous, no prescaler 0.5TCY + 5 — ns
Synchronous,
with prescaler
PIC18FXXX 10 — ns
PIC18LFXXX 25 — ns
Asynchronous PIC18FXXX 30 — ns
PIC18LFXXX 50 — ns
47 Tt1P T1CKI input
period
Synchronous Greater of:
20 nS or TCY + 40
N
— ns N = prescale
value
(1, 2, 4, 8)
Asynchronous 60 — ns
Ft1 T1CKI oscillator input frequency range DC 50 kHz
48 Tcke2tmrI Delay from external T1CKI clock edge to timer
increment
2 TOSC 7 TOSC —PIC18FXX2
DS39564C-page 276 © 2006 Microchip Technology Inc.
FIGURE 22-10: CAPTURE/COMPARE/PWM TIMINGS (CCP1 AND CCP2)
TABLE 22-9: CAPTURE/COMPARE/PWM REQUIREMENTS (CCP1 AND CCP2)
Note: Refer to Figure 22-4 for load conditions.
CCPx
(Capture Mode)
50 51
52
CCPx
53 54
(Compare or PWM Mode)
Param.
No. Symbol Characteristic Min Max Units Conditions
50 TccL CCPx input low
time
No Prescaler 0.5 TCY + 20 — ns
With
Prescaler
PIC18FXXX 10 — ns
PIC18LFXXX 20 — ns
51 TccH CCPx input
high time
No Prescaler 0.5 TCY + 20 — ns
With
Prescaler
PIC18FXXX 10 — ns
PIC18LFXXX 20 — ns
52 TccP CCPx input period 3 TCY + 40
N
— ns N = prescale
value (1,4 or 16)
53 TccR CCPx output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
54 TccF CCPx output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V© 2006 Microchip Technology Inc. DS39564C-page 277
PIC18FXX2
FIGURE 22-11: PARALLEL SLAVE PORT TIMING (PIC18F4X2)
TABLE 22-10: PARALLEL SLAVE PORT REQUIREMENTS (PIC18F4X2)
Note: Refer to Figure 22-4 for load conditions.
RE2/CS
RE0/RD
RE1/WR
RD7:RD0
62
63
64
65
Param.
No. Symbol Characteristic Min Max Units Conditions
62 TdtV2wrH Data in valid before WR↑ or CS↑
(setup time)
20
25
—
—
ns
ns Extended Temp. Range
63 TwrH2dtI WR↑ or CS↑ to data–in invalid
(hold time)
PIC18FXXX 20 — ns
PIC18LFXXX 35 — ns VDD = 2V
64 TrdL2dtV RD↓ and CS↓ to data–out valid —
—
80
90
ns
ns Extended Temp. Range
65 TrdH2dtI RD↑ or CS↓ to data–out invalid 10 30 ns
66 TibfINH Inhibit of the IBF flag bit being cleared from
WR↑ or CS↑
— 3 TCYPIC18FXX2
DS39564C-page 278 © 2006 Microchip Technology Inc.
FIGURE 22-12: EXAMPLE SPI MASTER MODE TIMING (CKE = 0)
TABLE 22-11: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 0)
Param.
No. Symbol Characteristic Min Max Units Conditions
70 TssL2scH,
TssL2scL
SS↓ to SCK↓ or SCK↑ input TCY — ns
71 TscH SCK input high time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 TscL SCK input low time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73 TdiV2scH,
TdiV2scL
Setup time of SDI data input to SCK edge 100 — ns
73A TB2B Last clock edge of Byte1 to the 1st clock edge of Byte2 1.5 TCY + 40 — ns (Note 2)
74 TscH2diL,
TscL2diL
Hold time of SDI data input to SCK edge 100 — ns
75 TdoR SDO data output rise time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
76 TdoF SDO data output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
78 TscR SCK output rise time
(Master mode)
PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
79 TscF SCK output fall time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
80 TscH2doV,
TscL2doV
SDO data output valid after SCK
edge
PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
70
71 72
73
74
75, 76
79 78 80
78 79
MSb LSb bit6 - - - - - -1
MSb In bit6 - - - -1 LSb In
Note: Refer to Figure 22-4 for load conditions.© 2006 Microchip Technology Inc. DS39564C-page 279
PIC18FXX2
FIGURE 22-13: EXAMPLE SPI MASTER MODE TIMING (CKE = 1)
TABLE 22-12: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 1)
Param.
No. Symbol Characteristic Min Max Units Conditions
71 TscH SCK input high time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 TscL SCK input low time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73 TdiV2scH,
TdiV2scL
Setup time of SDI data input to SCK edge 100 — ns
73A TB2B Last clock edge of Byte1 to the 1st clock edge of Byte2 1.5 TCY + 40 — ns (Note 2)
74 TscH2diL,
TscL2diL
Hold time of SDI data input to SCK edge 100 — ns
75 TdoR SDO data output rise time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
76 TdoF SDO data output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
78 TscR SCK output rise time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
79 TscF SCK output fall time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
80 TscH2doV,
TscL2doV
SDO data output valid after SCK
edge
PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
81 TdoV2scH,
TdoV2scL
SDO data output setup to SCK edge TCY — ns
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
81
71 72
74
75, 76
78
80
MSb
79
73
MSb In
bit6 - - - - - -1
bit6 - - - -1 LSb In
LSb
Note: Refer to Figure 22-4 for load conditions.PIC18FXX2
DS39564C-page 280 © 2006 Microchip Technology Inc.
FIGURE 22-14: EXAMPLE SPI SLAVE MODE TIMING (CKE = 0)
TABLE 22-13: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING (CKE = 0))
Param. No. Symbol Characteristic Min Max Units Conditions
70 TssL2scH,
TssL2scL
SS↓ to SCK↓ or SCK↑ input TCY — ns
71 TscH SCK input high time (Slave mode) Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 TscL SCK input low time (Slave mode) Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73 TdiV2scH,
TdiV2scL
Setup time of SDI data input to SCK edge 100 — ns
73A TB2B Last clock edge of Byte1 to the first clock edge of Byte2 1.5 TCY + 40 — ns (Note 2)
74 TscH2diL,
TscL2diL
Hold time of SDI data input to SCK edge 100 — ns
75 TdoR SDO data output rise time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
76 TdoF SDO data output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
77 TssH2doZ SS↑ to SDO output hi-impedance 10 50 ns
78 TscR SCK output rise time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
79 TscF SCK output fall time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
80 TscH2doV,
TscL2doV
SDO data output valid after SCK edge PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
83 TscH2ssH,
TscL2ssH
SS ↑ after SCK edge 1.5 TCY + 40 — ns
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
70
71 72
73
74
75, 76 77
79 78 80
78 79
SDI
MSb LSb bit6 - - - - - -1
MSb In bit6 - - - -1 LSb In
83
Note: Refer to Figure 22-4 for load conditions.© 2006 Microchip Technology Inc. DS39564C-page 281
PIC18FXX2
FIGURE 22-15: EXAMPLE SPI SLAVE MODE TIMING (CKE = 1)
TABLE 22-14: EXAMPLE SPI SLAVE MODE REQUIREMENTS (CKE = 1)
Param. No. Symbol Characteristic Min Max Units Conditions
70 TssL2scH,
TssL2scL
SS↓ to SCK↓ or SCK↑ input TCY — ns
71 TscH SCK input high time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 TscL SCK input low time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73A TB2B Last clock edge of Byte1 to the first clock edge of Byte2 1.5 TCY + 40 — ns (Note 2)
74 TscH2diL,
TscL2diL
Hold time of SDI data input to SCK edge 100 — ns
75 TdoR SDO data output rise time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
76 TdoF SDO data output fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
77 TssH2doZ SS↑ to SDO output hi-impedance 10 50 ns
78 TscR SCK output rise time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
79 TscF SCK output fall time (Master mode) PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
80 TscH2doV,
TscL2doV
SDO data output valid after SCK
edge
PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
82 TssL2doV SDO data output valid after SS↓ edge PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
83 TscH2ssH,
TscL2ssH
SS ↑ after SCK edge 1.5 TCY + 40 — ns
Note 1: Requires the use of Parameter # 73A.
2: Only if Parameter # 71A and # 72A are used.
SS
SCK
(CKP = 0)
SCK
(CKP = 1)
SDO
SDI
70
71 72
82
74
75, 76
MSb bit6 - - - - - -1 LSb
77
MSb In bit6 - - - -1 LSb In
80
83
Note: Refer to Figure 22-4 for load conditions.PIC18FXX2
DS39564C-page 282 © 2006 Microchip Technology Inc.
FIGURE 22-16: I2C BUS START/STOP BITS TIMING
TABLE 22-15: I2C BUS START/STOP BITS REQUIREMENTS (SLAVE MODE)
FIGURE 22-17: I2C BUS DATA TIMING
Note: Refer to Figure 22-4 for load conditions.
91
92
93
SCL
SDA
START
Condition
STOP
Condition
90
Param.
No. Symbol Characteristic Min Max Units Conditions
90 TSU:STA START condition 100 kHz mode 4700 — ns Only relevant for Repeated
Setup time 400 kHz mode 600 — START condition
91 THD:STA START condition 100 kHz mode 4000 — ns After this period, the first
Hold time 400 kHz mode 600 — clock pulse is generated
92 TSU:STO STOP condition 100 kHz mode 4700 — ns
Setup time 400 kHz mode 600 —
93 THD:STO STOP condition 100 kHz mode 4000 — ns
Hold time 400 kHz mode 600 —
Note: Refer to Figure 22-4 for load conditions.
90
91 92
100
101
103
106 107
109 109
110
102
SCL
SDA
In
SDA
Out© 2006 Microchip Technology Inc. DS39564C-page 283
PIC18FXX2
TABLE 22-16: I2C BUS DATA REQUIREMENTS (SLAVE MODE)
Param.
No. Symbol Characteristic Min Max Units Conditions
100 THIGH Clock high time 100 kHz mode 4.0 — μs PIC18FXXX must operate at a
minimum of 1.5 MHz
400 kHz mode 0.6 — μs PIC18FXXX must operate at a
minimum of 10 MHz
SSP Module 1.5 TCY —
101 TLOW Clock low time 100 kHz mode 4.7 — μs PIC18FXXX must operate at a
minimum of 1.5 MHz
400 kHz mode 1.3 — μs PIC18FXXX must operate at a
minimum of 10 MHz
SSP Module 1.5 TCY —
102 TR SDA and SCL rise
time
100 kHz mode — 1000 ns
400 kHz mode 20 + 0.1 CB 300 ns CB is specified to be from
10 to 400 pF
103 TF SDA and SCL fall
time
100 kHz mode — 1000 ns VDD ≥ 4.2V
400 kHz mode 20 + 0.1 CB 300 ns VDD ≥ 4.2V
90 TSU:STA START condition
setup time
100 kHz mode 4.7 — μs Only relevant for Repeated
START condition 400 kHz mode 0.6 — μs
91 THD:STA START condition hold
time
100 kHz mode 4.0 — μs After this period, the first clock
pulse is generated 400 kHz mode 0.6 — μs
106 THD:DAT Data input hold time 100 kHz mode 0 — ns
400 kHz mode 0 0.9 μs
107 TSU:DAT Data input setup time 100 kHz mode 250 — ns (Note 2)
400 kHz mode 100 — ns
92 TSU:STO STOP condition
setup time
100 kHz mode 4.7 — μs
400 kHz mode 0.6 — μs
109 TAA Output valid from
clock
100 kHz mode — 3500 ns (Note 1)
400 kHz mode — — ns
110 TBUF Bus free time 100 kHz mode 4.7 — μs Time the bus must be free
before a new transmission can
start
400 kHz mode 1.3 — μs
D102 CB Bus capacitive loading — 400 pF
Note 1: As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of
the falling edge of SCL to avoid unintended generation of START or STOP conditions.
2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but the requirement TSU:DAT ≥ 250 ns
must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If
such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line.
TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification) before the SCL line is
released. PIC18FXX2
DS39564C-page 284 © 2006 Microchip Technology Inc.
FIGURE 22-18: MASTER SSP I2C BUS START/STOP BITS TIMING WAVEFORMS
TABLE 22-17: MASTER SSP I2C BUS START/STOP BITS REQUIREMENTS
FIGURE 22-19: MASTER SSP I2C BUS DATA TIMING
Note: Refer to Figure 22-4 for load conditions.
91 93
SCL
SDA
START
Condition
STOP
Condition
90 92
Param.
No. Symbol Characteristic Min Max Units Conditions
90 TSU:STA START condition 100 kHz mode 2(TOSC)(BRG + 1) — ns Only relevant for
Repeated START
condition Setup time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1) 2(TOSC)(BRG + 1) —
91 THD:STA START condition 100 kHz mode 2(TOSC)(BRG + 1) — ns After this period, the
first clock pulse is
generated Hold time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1) 2(TOSC)(BRG + 1) —
92 TSU:STO STOP condition 100 kHz mode 2(TOSC)(BRG + 1) — ns
Setup time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1) 2(TOSC)(BRG + 1) —
93 THD:STO STOP condition 100 kHz mode 2(TOSC)(BRG + 1) — ns
Hold time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1) 2(TOSC)(BRG + 1) —
Note 1: Maximum pin capacitance = 10 pF for all I2C pins.
Note: Refer to Figure 22-4 for load conditions.
90
91 92
100
101
103
106
107
109 109 110
102
SCL
SDA
In
SDA
Out© 2006 Microchip Technology Inc. DS39564C-page 285
PIC18FXX2
TABLE 22-18: MASTER SSP I2C BUS DATA REQUIREMENTS
Param.
No. Symbol Characteristic Min Max Units Conditions
100 THIGH Clock high time 100 kHz mode 2(TOSC)(BRG + 1) — ms
400 kHz mode 2(TOSC)(BRG + 1) — ms
1 MHz mode(1) 2(TOSC)(BRG + 1) — ms
101 TLOW Clock low time 100 kHz mode 2(TOSC)(BRG + 1) — ms
400 kHz mode 2(TOSC)(BRG + 1) — ms
1 MHz mode(1) 2(TOSC)(BRG + 1) — ms
102 TR SDA and SCL
rise time
100 kHz mode — 1000 ns CB is specified to be from
10 to 400 pF 400 kHz mode 20 + 0.1 CB 300 ns
1 MHz mode(1) — 300 ns
103 TF SDA and SCL
fall time
100 kHz mode — 1000 ns VDD ≥ 4.2V
400 kHz mode 20 + 0.1 CB 300 ns VDD ≥ 4.2V
90 TSU:STA START condition
setup time
100 kHz mode 2(TOSC)(BRG + 1) — ms Only relevant for
Repeated START
condition 400 kHz mode 2(TOSC)(BRG + 1) — ms
1 MHz mode(1) 2(TOSC)(BRG + 1) — ms
91 THD:STA START condition
hold time
100 kHz mode 2(TOSC)(BRG + 1) — ms After this period, the first
clock pulse is generated 400 kHz mode 2(TOSC)(BRG + 1) — ms
1 MHz mode(1) 2(TOSC)(BRG + 1) — ms
106 THD:DAT Data input
hold time
100 kHz mode 0 — ns
400 kHz mode 0 0.9 ms
107 TSU:DAT Data input
setup time
100 kHz mode 250 — ns (Note 2)
400 kHz mode 100 — ns
92 TSU:STO STOP condition
setup time
100 kHz mode 2(TOSC)(BRG + 1) — ms
400 kHz mode 2(TOSC)(BRG + 1) — ms
1 MHz mode(1) 2(TOSC)(BRG + 1) — ms
109 TAA Output valid from
clock
100 kHz mode — 3500 ns
400 kHz mode — 1000 ns
1 MHz mode(1) — — ns
110 TBUF Bus free time 100 kHz mode 4.7 — ms Time the bus must be free
before a new transmission
can start
400 kHz mode 1.3 — ms
D102 CB Bus capacitive loading — 400 pF
Note 1: Maximum pin capacitance = 10 pF for all I2C pins.
2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but parameter #107 ≥ 250 ns
must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL
signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the
SDA line, parameter #102 + parameter #107 = 1000 + 250 = 1250 ns (for 100 kHz mode) before the SCL line
is released.PIC18FXX2
DS39564C-page 286 © 2006 Microchip Technology Inc.
FIGURE 22-20: USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
TABLE 22-19: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
FIGURE 22-21: USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
TABLE 22-20: USART SYNCHRONOUS RECEIVE REQUIREMENTS
121 121
120
122
RC6/TX/CK
RC7/RX/DT
pin
pin
Note: Refer to Figure 22-4 for load conditions.
Param.
No. Symbol Characteristic Min Max Units Conditions
120 TckH2dtV SYNC XMIT (MASTER & SLAVE)
Clock high to data out valid PIC18FXXX — 50 ns
PIC18LFXXX — 150 ns VDD = 2V
121 Tckr Clock out rise time and fall time
(Master mode)
PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
122 Tdtr Data out rise time and fall time PIC18FXXX — 25 ns
PIC18LFXXX — 60 ns VDD = 2V
125
126
RC6/TX/CK
RC7/RX/DT
pin
pin
Note: Refer to Figure 22-4 for load conditions.
Param.
No. Symbol Characteristic Min Max Units Conditions
125 TdtV2ckl SYNC RCV (MASTER & SLAVE)
Data hold before CK ↓ (DT hold time) 10 — ns
126 TckL2dtl Data hold after CK ↓ (DT hold time) PIC18FXXX 15 — ns
PIC18LFXXX 20 — ns VDD = 2V© 2006 Microchip Technology Inc. DS39564C-page 287
PIC18FXX2
TABLE 22-21: A/D CONVERTER CHARACTERISTICS: PIC18FXX2 (INDUSTRIAL, EXTENDED)
PIC18LFXX2 (INDUSTRIAL)
FIGURE 22-22: A/D CONVERSION TIMING
Param
No. Symbol Characteristic Min Typ Max Units Conditions
A01 NR Resolution — — 10 bit
A03 EIL Integral linearity error — — <±1 LSb VREF = VDD = 5.0V
A04 EDL Differential linearity error — — <±1 LSb VREF = VDD = 5.0V
A05 EG Gain error — — <±1 LSb VREF = VDD = 5.0V
A06 EOFF Offset error — — <±1.5 LSb VREF = VDD = 5.0V
A10 — Monotonicity guaranteed(2) — VSS ≤ VAIN ≤ VREF
A20
A20A
VREF Reference Voltage
(VREFH – VREFL)
1.8V
3V
—
—
—
—
V
V
VDD < 3.0V
VDD ≥ 3.0V
A21 VREFH Reference voltage High AVSS — AVDD + 0.3V V
A22 VREFL Reference voltage Low AVSS – 0.3V — VREFH V
A25 VAIN Analog input voltage AVSS – 0.3V — AVDD + 0.3V V VDD ≥ 2.5V (Note 3)
A30 ZAIN Recommended impedance of
analog voltage source
— — 2.5 kΩ (Note 4)
A50 IREF VREF input current (Note 1) —
—
—
—
5
150
μA
μA
During VAIN acquisition
During A/D conversion cycle
Note 1: Vss ≤ VAIN ≤ VREF
2: The A/D conversion result never decreases with an increase in the Input Voltage, and has no missing codes.
3: For VDD < 2.5V, VAIN should be limited to < .5 VDD.
4: Maximum allowed impedance for analog voltage source is 10 kΩ. This requires higher acquisition times.
131
130
132
BSF ADCON0, GO
Q4
A/D CLK
A/D DATA
ADRES
ADIF
GO
SAMPLE
OLD_DATA
SAMPLING STOPPED
DONE
NEW_DATA
(Note 2)
9 87 2 1 0
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts.
This allows the SLEEP instruction to be executed.
2: This is a minimal RC delay (typically 100 nS), which also disconnects the holding capacitor from the analog input.
. . . . . .
TCYPIC18FXX2
DS39564C-page 288 © 2006 Microchip Technology Inc.
TABLE 22-22: A/D CONVERSION REQUIREMENTS
Param
No. Symbol Characteristic Min Max Units Conditions
130 TAD A/D clock period PIC18FXXX 1.6 20(4) μs TOSC based
PIC18FXXX 2.0 6.0 μs A/D RC mode
131 TCNV Conversion time
(not including acquisition time) (Note 1)
11 12 TAD
132 TACQ Acquisition time (Note 2) 5
10
—
—
μs
μs
VREF = VDD = 5.0V
VREF = VDD = 2.5V
135 TSWC Switching Time from convert → sample — (Note 3)
Note 1: ADRES register may be read on the following TCY cycle.
2: The time for the holding capacitor to acquire the “New” input voltage, when the new input value has not
changed by more than 1 LSB from the last sampled voltage. The source impedance (RS) on the input channels
is 50Ω. See Section 17.0 for more information on acquisition time consideration.
3: On the next Q4 cycle of the device clock.
4: The time of the A/D clock period is dependent on the device frequency and the TAD clock divider. © 2006 Microchip Technology Inc. DS39564C-page 289
PIC18FXX2
23.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES
“Typical” represents the mean of the distribution at 25°C. “Maximum” or “minimum” represents (mean + 3σ) or (mean - 3σ)
respectively, where σ is a standard deviation, over the whole temperature range.
FIGURE 23-1: TYPICAL IDD vs. FOSC OVER VDD (HS MODE)
FIGURE 23-2: MAXIMUM IDD vs. FOSC OVER VDD (HS MODE)
Note: The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein are
not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.
0
2
4
6
8
10
12
4 6 8 10 12 14 16 18 20 22 24 26
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
2
4
6
8
10
12
4 6 8 10 12 14 16 18 20 22 24 26
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)PIC18FXX2
DS39564C-page 290 © 2006 Microchip Technology Inc.
FIGURE 23-3: TYPICAL IDD vs. FOSC OVER VDD (HS/PLL MODE)
FIGURE 23-4: MAXIMUM IDD vs. FOSC OVER VDD (HS/PLL MODE)
0
2
4
6
8
10
12
14
16
18
20
4 5 6 7 8 9 10
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.2V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
2
4
6
8
10
12
14
16
18
20
4 5 6 7 8 9 10
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.2V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)© 2006 Microchip Technology Inc. DS39564C-page 291
PIC18FXX2
FIGURE 23-5: TYPICAL IDD vs. FOSC OVER VDD (XT MODE)
FIGURE 23-6: MAXIMUM IDD vs. FOSC OVER VDD (XT MODE)
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
FOSC (MHz)
IDD (uA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
IDD (μA)
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
FOSC (MHz)
IDD (μA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)PIC18FXX2
DS39564C-page 292 © 2006 Microchip Technology Inc.
FIGURE 23-7: TYPICAL IDD vs. FOSC OVER VDD (LP MODE)
FIGURE 23-8: MAXIMUM IDD vs. FOSC OVER VDD (LP MODE)
0
10
20
30
40
50
60
70
80
90
100
20 30 40 50 60 70 80 90 100
FOSC (kHz)
IDD (uA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
20
40
60
80
100
120
140
20 30 40 50 60 70 80 90 100
FOSC (kHz)
IDD (uA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)© 2006 Microchip Technology Inc. DS39564C-page 293
PIC18FXX2
FIGURE 23-9: TYPICAL IDD vs. FOSC OVER VDD (EC MODE)
FIGURE 23-10: MAXIMUM IDD vs. FOSC OVER VDD (EC MODE)
0
2
4
6
8
10
12
14
16
4 8 12 16 20 24 28 32 36 40
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
4.2V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
2
4
6
8
10
12
14
16
4 8 12 16 20 24 28 32 36 40
FOSC (MHz)
IDD (mA)
5.5V
5.0V
4.5V
4.0V
3.5V
3.0V
2.5V
2.0V
4.2V
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)PIC18FXX2
DS39564C-page 294 © 2006 Microchip Technology Inc.
FIGURE 23-11: TYPICAL AND MAXIMUM IDD vs. VDD
(TIMER1 AS MAIN OSCILLATOR, 32.768 kHz, C1 AND C2 = 47 pF)
FIGURE 23-12: AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R
(RC MODE, C = 20 pF, +25°C)
0
20
40
60
80
100
120
140
160
180
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IPD (uA)
Typ (25C)
Max (70C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-10°C to 70°C)
Minimum: mean – 3σ (-10°C to 70°C)
IDD (μA)
Max (+70°C)
Typ (+25°C)
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
Freq (kHz)
3.3kΩ
5.1kΩ
10kΩ
100kΩ
Operation above 4 MHz is not recommended.© 2006 Microchip Technology Inc. DS39564C-page 295
PIC18FXX2
FIGURE 23-13: AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R
(RC MODE, C = 100 pF, +25°C)
FIGURE 23-14: AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R
(RC MODE, C = 300 pF, +25°C)
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
Freq (kHz)
3.3kΩ
5.1kΩ
10kΩ
100kΩ
0
100
200
300
400
500
600
700
800
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
Freq (MHz)
3.3kΩ
5.1kΩ
10kΩ
100kΩPIC18FXX2
DS39564C-page 296 © 2006 Microchip Technology Inc.
FIGURE 23-15: IPD vs. VDD, -40°C TO +125°C (SLEEP MODE, ALL PERIPHERALS DISABLED)
FIGURE 23-16: ΔIBOR vs. VDD OVER TEMPERATURE (BOR ENABLED, VBOR = 2.00 - 2.16V)
0.01
0.1
1
10
100
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IPD (uA)
Typ (+25°C)
Max
(+85°C)
Max
(-40°C to +125°C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
10
20
30
40
50
60
70
80
90
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IDD (μA)
Max (125C)
Max (85C)
Typ (25C)
Device
Held in
Reset
Device
in
Sleep
Max (+125°C)
Max (+85°C)
Typ (+25°C)
Device
Held in
RESET
Device
in
SLEEP© 2006 Microchip Technology Inc. DS39564C-page 297
PIC18FXX2
FIGURE 23-17: TYPICAL AND MAXIMUM ΔITMR1 vs. VDD OVER TEMPERATURE (-10°C TO +70°C,
TIMER1 WITH OSCILLATOR, XTAL = 32 kHz, C1 AND C2 = 47 pF)
FIGURE 23-18: TYPICAL AND MAXIMUM ΔIWDT vs. VDD OVER TEMPERATURE (WDT ENABLED)
0
2
4
6
8
10
12
14
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IPD (uA)
Typ (25C)
Max (70C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-10°C to 70°C)
Minimum: mean – 3σ (-10°C to 70°C)
IPD (μA)
Max (+70°C)
Typ (+25°C)
0
10
20
30
40
50
60
70
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IPD (μA)
Max (125C)
Max (85C)
Typ (25C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Max (+125°C)
Max (+85°C)
Typ (+25°C)PIC18FXX2
DS39564C-page 298 © 2006 Microchip Technology Inc.
FIGURE 23-19: TYPICAL, MINIMUM AND MAXIMUM WDT PERIOD vs. VDD (-40°C TO +125°C)
FIGURE 23-20: ΔILVD vs. VDD OVER TEMPERATURE (LVD ENABLED, VLVD = 4.5 - 4.78V)
0
5
10
15
20
25
30
35
40
45
50
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
WDT Period (ms)
Max
(125C)
MAX
(85C)
Typ
(25C)
Min
(-40C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Max
(+125°C)
Max
(+85°C)
Typ
(+25°C)
Min
(-40°C)
0
10
20
30
40
50
60
70
80
90
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
IDD (μA)
Max (125C)
Typ (25C)
Max (125C)
Typ (25C)
LVDIF is set
by hardware
LVDIF can be
cleared by
firmware
LVDIF state
is unknown
Max (+125°C)
Max (+125°C)
Typ (+25°C)
Typ (+25°C)© 2006 Microchip Technology Inc. DS39564C-page 299
PIC18FXX2
FIGURE 23-21: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 5V, -40°C TO +125°C)
FIGURE 23-22: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 3V, -40°C TO +125°C)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0 5 10 15 20 25
IOH (-mA)
VOH (V)
Typ (25C)
Max
Min
Max
Typ (+25°C)
Min
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 5 10 15 20 25
IOH (-mA)
VOH (V)
Typ (25C)
Max
Min
Typ (+25°C)
Min
MaxPIC18FXX2
DS39564C-page 300 © 2006 Microchip Technology Inc.
FIGURE 23-23: TYPICAL AND MAXIMUM VOL vs. IOL (VDD = 5V, -40°C TO +125°C)
FIGURE 23-24: TYPICAL AND MAXIMUM VOL vs. IOL (VDD = 3V, -40°C TO +125°C)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0 5 10 15 20 25
IOL (-mA)
VOL (V)
Max
Typ (25C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Typ (+25°C)
Max
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15 20 25
IOL (-mA)
VOL (V)
Max
Typ (25C)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
Typ (+25°C)
Max© 2006 Microchip Technology Inc. DS39564C-page 301
PIC18FXX2
FIGURE 23-25: MINIMUM AND MAXIMUM VIN vs. VDD (ST INPUT, -40°C TO +125°C)
FIGURE 23-26: MINIMUM AND MAXIMUM VIN vs. VDD (TTL INPUT, -40°C TO +125°C)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
VIN (V)
VIH Max
VIH Min
VIL Max
VIL Min
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
VIN (V)
VTH (Max)
VTH (Min)
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)PIC18FXX2
DS39564C-page 302 © 2006 Microchip Technology Inc.
FIGURE 23-27: MINIMUM AND MAXIMUM VIN vs. VDD (I2C INPUT, -40°C TO +125°C)
FIGURE 23-28: A/D NON-LINEARITY vs. VREFH (VDD = VREFH, -40°C TO +125°C)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VDD (V)
VIN (V)
VIH Max
VIH Min
VILMax
VIL Min
Typical: statistical mean @ 25°C
Maximum: mean + 3σ (-40°C to 125°C)
Minimum: mean – 3σ (-40°C to 125°C)
0
0.5
1
1.5
2
2.5
3
3.5
4
2 2.5 3 3.5 4 4.5 5 5.5
VDD and VREFH (V)
Differential or Integral Nonlinearity (LSB)
-40C
25C
85C
125C
-40°C
+25°C
+85°C
+125°C© 2006 Microchip Technology Inc. DS39564C-page 303
PIC18FXX2
FIGURE 23-29: A/D NON-LINEARITY vs. VREFH (VDD = 5V, -40°C TO +125°C)
0
0.5
1
1.5
2
2.5
3
2 2.5 3 3.5 4 4.5 5 5.5
VREFH (V)
Differential or Integral Nonlinearilty (LSB)
Max (-40C to 125C)
Typ (+25°C) Typ (25C)
Max (-40°C to +125°C)PIC18FXX2
DS39564C-page 304 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 305
PIC18FXX2
24.0 PACKAGING INFORMATION
24.1 Package Marking Information
28-Lead SPDIP
XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN
Example
PIC18F242-I/SP
0610017
28-Lead SOIC
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXX
YYWWNNN
Example
PIC18F242-E/SO
0610017
40-Lead PDIP
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
YYWWNNN
Example
PIC18F442-I/P
0610017
Legend: XX...X Customer-specific information
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
* This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
e3
e3
e3
e3
e3PIC18FXX2
DS39564C-page 306 © 2006 Microchip Technology Inc.
Package Marking Information (Cont’d)
44-Lead TQFP
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
Example
PIC18F452
-E/PT
0610017
44-Lead PLCC
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
Example
PIC18F442
-I/L
0610017
e3
e3© 2006 Microchip Technology Inc. DS39564C-page 307
PIC18FXX2
24.2 Package Details
The following sections give the technical details of the packages.
28-Lead Skinny Plastic Dual In-line (SP) – 300 mil Body (PDIP)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Mold Draft Angle Bottom β 5 10 15 5 10 15
Mold Draft Angle Top α 5 10 15 5 10 15
Overall Row Spacing § eB .320 .350 .430 8.13 8.89 10.92
Lower Lead Width B .016 .019 .022 0.41 0.48 0.56
Upper Lead Width B1 .040 .053 .065 1.02 1.33 1.65
Lead Thickness c .008 .012 .015 0.20 0.29 0.38
Tip to Seating Plane L .125 .130 .135 3.18 3.30 3.43
Overall Length D 1.345 1.365 1.385 34.16 34.67 35.18
Molded Package Width E1 .275 .285 .295 6.99 7.24 7.49
Shoulder to Shoulder Width E .300 .310 .325 7.62 7.87 8.26
Base to Seating Plane A1 .015 0.38
Molded Package Thickness A2 .125 .130 .135 3.18 3.30 3.43
Top to Seating Plane A .140 .150 .160 3.56 3.81 4.06
Pitch p .100 2.54
Number of Pins n 28 28
Dimension Limits MIN NOM MAX MIN NOM MAX
Units INCHES* MILLIMETERS
2
1
D
n
E1
c
eB
β
E
α
p
L
A2
B
B1
A
A1
Notes:
JEDEC Equivalent: MO-095
Drawing No. C04-070
* Controlling Parameter
Dimension D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side.
§ Significant CharacteristicPIC18FXX2
DS39564C-page 308 © 2006 Microchip Technology Inc.
28-Lead Plastic Small Outline (SO) – Wide, 300 mil Body (SOIC)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Foot Angle Top φ 048048
Mold Draft Angle Bottom β 0 12 15 0 12 15
Mold Draft Angle Top α 0 12 15 0 12 15
Lead Width B .014 .017 .020 0.36 0.42 0.51
Lead Thickness c .009 .011 .013 0.23 0.28 0.33
Foot Length L .016 .033 .050 0.41 0.84 1.27
Chamfer Distance h .010 .020 .029 0.25 0.50 0.74
Overall Length D .695 .704 .712 17.65 17.87 18.08
Molded Package Width E1 .288 .295 .299 7.32 7.49 7.59
Overall Width E .394 .407 .420 10.01 10.34 10.67
Standoff § A1 .004 .008 .012 0.10 0.20 0.30
Molded Package Thickness A2 .088 .091 .094 2.24 2.31 2.39
Overall Height A .093 .099 .104 2.36 2.50 2.64
Pitch p .050 1.27
Number of Pins n 28 28
Dimension Limits MIN NOM MAX MIN NOM MAX
Units INCHES* MILLIMETERS
2
1
D
p
n
B
E
E1
L
c
β
45°
h
φ
A2
α
A
A1
* Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side.
JEDEC Equivalent: MS-013
Drawing No. C04-052
§ Significant Characteristic© 2006 Microchip Technology Inc. DS39564C-page 309
PIC18FXX2
40-Lead Plastic Dual In-line (P) – 600 mil Body (PDIP)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Mold Draft Angle Bottom β 5 10 15 5 10 15
Mold Draft Angle Top α 5 10 15 5 10 15
Overall Row Spacing § eB .620 .650 .680 15.75 16.51 17.27
Lower Lead Width B .014 .018 .022 0.36 0.46 0.56
Upper Lead Width B1 .030 .050 .070 0.76 1.27 1.78
Lead Thickness c .008 .012 .015 0.20 0.29 0.38
Tip to Seating Plane L .120 .130 .135 3.05 3.30 3.43
Overall Length D 2.045 2.058 2.065 51.94 52.26 52.45
Molded Package Width E1 .530 .545 .560 13.46 13.84 14.22
Shoulder to Shoulder Width E .595 .600 .625 15.11 15.24 15.88
Base to Seating Plane A1 .015 0.38
Molded Package Thickness A2 .140 .150 .160 3.56 3.81 4.06
Top to Seating Plane A .160 .175 .190 4.06 4.45 4.83
Pitch p .100 2.54
Number of Pins n 40 40
Dimension Limits MIN NOM MAX MIN NOM MAX
Units INCHES* MILLIMETERS
A2
1
2
D
n
E1
c
β
eB
E
α
p
L
B
B1
A
A1
* Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side.
JEDEC Equivalent: MO-011
Drawing No. C04-016
§ Significant CharacteristicPIC18FXX2
DS39564C-page 310 © 2006 Microchip Technology Inc.
44-Lead Plastic Thin Quad Flatpack (PT) 10x10x1 mm Body, 1.0/0.10 mm Lead Form (TQFP)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
F
A
A1 A2
α
E
E1
#leads=n1
p
B
D1 D
n
1
2
φ
c
β
L
CH x 45°
Pin 1 Corner Chamfer CH .025 .035 .045 0.64 0.89 1.14
Footprint (Reference) F .039 REF. 1.00 REF.
Units INCHES MILLIMETERS*
Dimension Limits MIN NOM MAX MIN NOM MAX
Number of Pins n 44 44
Pitch p .031 0.80
Overall Height A .039 .043 .047 1.00 1.10 1.20
Molded Package Thickness A2 .037 .039 .041 0.95 1.00 1.05
Standoff A1 .002 .004 .006 0.05 0.10 0.15
Foot Length L .018 .024 .030 0.45 0.60 0.75
Foot Angle φ 0 3.5 7 0 3.5 7
Overall Width E .463 .472 .482 11.75 12.00 12.25
Overall Length D .463 .472 .482 11.75 12.00 12.25
Molded Package Width E1 .390 .394 .398 9.90 10.00 10.10
Molded Package Length D1 .390 .394 .398 9.90 10.00 10.10
Pins per Side n1 11 11
Lead Thickness c .004 .006 .008 0.09 0.15 0.20
Lead Width B .012 .015 .017 0.30 0.38 0.44
Mold Draft Angle Top α 5 10 15 5 10 15
Mold Draft Angle Bottom β 5 10 15 5 10 15
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side.
Notes:
JEDEC Equivalent: MS-026
Revised 07-22-05
* Controlling Parameter
REF: Reference Dimension, usually without tolerance, for information purposes only.
See ASME Y14.5M
Drawing No. C04-076© 2006 Microchip Technology Inc. DS39564C-page 311
PIC18FXX2
44-Lead Plastic Leaded Chip Carrier (L) – Square (PLCC)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
CH2 x 45° CH1 x 45°
Mold Draft Angle Bottom β 0 5 10 0 5 10
Mold Draft Angle Top α 0 5 10 0 5 10
B .013 .020 .021 0.33 0.51 0.53
Upper Lead Width B1 .026 .029 .032 0.66 0.74 0.81
Lead Thickness c .008 .011 .013 0.20 0.27 0.33
Pins per Side n1 11 11
Footprint Length D2 .590 .620 .630 14.99 15.75 16.00
Footprint Width E2 .590 .620 .630 14.99 15.75 16.00
Molded Package Length D1 .650 .653 .656 16.51 16.59 16.66
Molded Package Width E1 .650 .653 .656 16.51 16.59 16.66
Overall Length D .685 .690 .695 17.40 17.53 17.65
Overall Width E .685 .690 .695 17.40 17.53 17.65
Corner Chamfer (others) CH2 .000 .005 .010 0.00 0.13 0.25
Corner Chamfer 1 CH1 .040 .045 .050 1.02 1.14 1.27
Side 1 Chamfer Height A3 .024 .029 .034 0.61 0.74 0.86
Standoff § A1 .020 0.51
Molded Package Thickness A2
Overall Height A .165 .173 .180 4.19 4.39 4.57
Pitch p .050 1.27
Number of Pins n 44 44
Dimension Limits MIN NOM MAX MIN NOM MAX
Units INCHES* MILLIMETERS
β
A2
c
E2
2
D1 D
n
#leads=n1
E
E1
1
α
p
A3
A 35°
B1
B
D2
A1
.145 .153 .160 3.68 3.87 4.06
.028 .035 0.71 0.89
Lower Lead Width
* Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side.
JEDEC Equivalent: MO-047
Drawing No. C04-048
§ Significant CharacteristicPIC18FXX2
DS39564C-page 312 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 313
PIC18FXX2
APPENDIX A: REVISION HISTORY
Revision A (June 2001)
Original data sheet for the PIC18FXX2 family.
Revision B (August 2002)
This revision includes the DC and AC Characteristics
Graphs and Tables. The Electrical Specifications in
Section 22.0 have been updated and there have been
minor corrections to the data sheet text.
Revision C (October 2006)
Packaging diagrams updated.
APPENDIX B: DEVICE
DIFFERENCES
The differences between the devices listed in this data
sheet are shown in Table B-1.
TABLE B-1: DEVICE DIFFERENCES
Feature PIC18F242 PIC18F252 PIC18F442 PIC18F452
Program Memory (Kbytes) 16 32 16 32
Data Memory (Bytes) 768 1536 768 1536
A/D Channels 5 5 8 8
Parallel Slave Port (PSP) No No Yes Yes
Package Types 28-pin DIP
28-pin SOIC
28-pin DIP
28-pin SOIC
40-pin DIP
44-pin PLCC
44-pin TQFP
40-pin DIP
44-pin PLCC
44-pin TQFPPIC18FXX2
DS39564C-page 314 © 2006 Microchip Technology Inc.
APPENDIX C: CONVERSION
CONSIDERATIONS
This appendix discusses the considerations for converting
from previous versions of a device to the ones
listed in this data sheet. Typically, these changes are
due to the differences in the process technology used.
An example of this type of conversion is from a
PIC16C74A to a PIC16C74B.
Not Applicable
APPENDIX D: MIGRATION FROM
BASELINE TO
ENHANCED DEVICES
This section discusses how to migrate from a Baseline
device (i.e., PIC16C5X) to an Enhanced MCU device
(i.e., PIC18FXXX).
The following are the list of modifications over the
PIC16C5X microcontroller family:
Not Currently Available© 2006 Microchip Technology Inc. DS39564C-page 315
PIC18FXX2
APPENDIX E: MIGRATION FROM
MID-RANGE TO
ENHANCED DEVICES
A detailed discussion of the differences between the
mid-range MCU devices (i.e., PIC16CXXX) and the
enhanced devices (i.e., PIC18FXXX) is provided in
AN716, “Migrating Designs from PIC16C74A/74B to
PIC18F442”. The changes discussed, while device
specific, are generally applicable to all mid-range to
enhanced device migrations.
This Application Note is available as Literature Number
DS00716.
APPENDIX F: MIGRATION FROM
HIGH-END TO
ENHANCED DEVICES
A detailed discussion of the migration pathway and differences
between the high-end MCU devices (i.e.,
PIC17CXXX) and the enhanced devices (i.e.,
PIC18FXXX) is provided in AN726, “PIC17CXXX to
PIC18FXXX Migration”. This Application Note is
available as Literature Number DS00726.PIC18FXX2
DS39564C-page 316 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 317
PIC18FXX2
INDEX
A
A/D ................................................................................... 181
A/D Converter Flag (ADIF Bit) ................................. 183
A/D Converter Interrupt, Configuring ....................... 184
Acquisition Requirements ........................................ 184
ADCON0 Register .................................................... 181
ADCON1 Register .................................................... 181
ADRESH Register .................................................... 181
ADRESH/ADRESL Registers .................................. 183
ADRESL Register .................................................... 181
Analog Port Pins ................................................ 99, 100
Analog Port Pins, Configuring .................................. 186
Associated Registers ............................................... 188
Configuring the Module ............................................ 184
Conversion Clock (TAD) ........................................... 186
Conversion Status (GO/DONE Bit) .......................... 183
Conversions ............................................................. 187
Converter Characteristics ........................................ 287
Equations
Acquisition Time ............................................... 185
Minimum Charging Time .................................. 185
Examples
Calculating the Minimum Required
Acquisition Time ...................................... 185
Result Registers ....................................................... 187
Special Event Trigger (CCP) ............................ 120, 188
TAD vs. Device Operating Frequencies .................... 186
Use of the CCP2 Trigger .......................................... 188
Absolute Maximum Ratings ............................................. 259
AC (Timing) Characteristics ............................................. 269
Load Conditions for Device Timing
Specifications ................................................... 270
Parameter Symbology ............................................. 269
Temperature and Voltage Specifications - AC ......... 270
Timing Conditions .................................................... 270
ACKSTAT Status Flag ..................................................... 155
ADCON0 Register ............................................................ 181
GO/DONE Bit ........................................................... 183
ADCON1 Register ............................................................ 181
ADDLW ............................................................................ 217
ADDWF ............................................................................ 217
ADDWFC ......................................................................... 218
ADRESH Register ............................................................ 181
ADRESH/ADRESL Registers ........................................... 183
ADRESL Register ............................................................ 181
Analog-to-Digital Converter. See A/D
ANDLW ............................................................................ 218
ANDWF ............................................................................ 219
Assembler
MPASM Assembler .................................................. 253
B
Baud Rate Generator ....................................................... 151
BC .................................................................................... 219
BCF .................................................................................. 220
BF Status Flag ................................................................. 155
Block Diagrams
A/D Converter .......................................................... 183
Analog Input Model .................................................. 184
Baud Rate Generator .............................................. 151
Capture Mode Operation ......................................... 119
Compare Mode Operation ....................................... 120
Low Voltage Detect
External Reference Source ............................. 190
Internal Reference Source ............................... 190
MSSP
I
2C Mode ......................................................... 134
MSSP (SPI Mode) ................................................... 125
On-Chip Reset Circuit ................................................ 25
Parallel Slave Port (PORTD and PORTE) ............... 100
PIC18F2X2 .................................................................. 8
PIC18F4X2 .................................................................. 9
PLL ............................................................................ 19
PORTC (Peripheral Output Override) ........................ 93
PORTD (I/O Mode) .................................................... 95
PORTE (I/O Mode) .................................................... 97
PWM Operation (Simplified) .................................... 122
RA3:RA0 and RA5 Port Pins ..................................... 87
RA4/T0CKI Pin .......................................................... 88
RA6 Pin ..................................................................... 88
RB2:RB0 Port Pins .................................................... 91
RB3 Pin ..................................................................... 91
RB7:RB4 Port Pins .................................................... 90
Table Read Operation ............................................... 55
Table Write Operation ................................................ 56
Table Writes to FLASH Program Memory ................. 61
Timer0 in 16-bit Mode .............................................. 104
Timer0 in 8-bit Mode ................................................ 104
Timer1 ..................................................................... 108
Timer1 (16-bit R/W Mode) ....................................... 108
Timer2 ..................................................................... 112
Timer3 ..................................................................... 114
Timer3 (16-bit R/W Mode) ....................................... 114
USART
Asynchronous Receive .................................... 174
Asynchronous Transmit ................................... 172
Watchdog Timer ...................................................... 204
BN .................................................................................... 220
BNC ................................................................................. 221
BNN ................................................................................. 221
BNOV ............................................................................... 222
BNZ .................................................................................. 222
BOR. See Brown-out Reset
BOV ................................................................................. 225
BRA ................................................................................. 223
BRG. See Baud Rate Generator
Brown-out Reset (BOR) ..................................................... 26
BSF .................................................................................. 223
BTFSC ............................................................................. 224
BTFSS ............................................................................. 224
BTG ................................................................................. 225
Bus Collision During a STOP Condition .......................... 163
BZ .................................................................................... 226PIC18FXX2
DS39564C-page 318 © 2006 Microchip Technology Inc.
C
CALL ................................................................................ 226
Capture (CCP Module) ..................................................... 119
Associated Registers ...............................................121
CCP Pin Configuration ............................................. 119
CCPR1H:CCPR1L Registers ................................... 119
Software Interrupt ..................................................... 119
Timer1/Timer3 Mode Selection ................................ 119
Capture/Compare/PWM (CCP) ........................................ 117
Capture Mode. See Capture
CCP1 ........................................................................118
CCPR1H Register ............................................ 118
CCPR1L Register ............................................ 118
CCP2 ........................................................................118
CCPR2H Register ............................................ 118
CCPR2L Register ............................................ 118
Compare Mode. See Compare
Interaction of Two CCP Modules ............................. 118
PWM Mode. See PWM
Timer Resources ...................................................... 118
Clocking Scheme/Instruction Cycle .................................... 39
CLRF ................................................................................ 227
CLRWDT .......................................................................... 227
Code Examples
16 x 16 Signed Multiply Routine ................................. 72
16 x 16 Unsigned Multiply Routine ............................. 72
8 x 8 Signed Multiply Routine ..................................... 71
8 x 8 Unsigned Multiply Routine ................................. 71
Changing Between Capture Prescalers ................... 119
Data EEPROM Read .................................................67
Data EEPROM Refresh Routine ................................68
Data EEPROM Write .................................................. 67
Erasing a FLASH Program Memory Row .................. 60
Fast Register Stack .................................................... 39
How to Clear RAM (Bank1) Using
Indirect Addressing ............................................ 50
Initializing PORTA ...................................................... 87
Initializing PORTB ...................................................... 90
Initializing PORTC ...................................................... 93
Initializing PORTD ...................................................... 95
Initializing PORTE ...................................................... 97
Loading the SSPBUF (SSPSR) Register ................. 128
Reading a FLASH Program Memory Word ................ 59
Saving STATUS, WREG and BSR
Registers in RAM ............................................... 85
Writing to FLASH Program Memory ..................... 62–63
Code Protection ............................................................... 195
COMF ............................................................................... 228
Compare (CCP Module) ...................................................120
Associated Registers ...............................................121
CCP Pin Configuration ............................................. 120
CCPR1 Register ....................................................... 120
Software Interrupt ..................................................... 120
Special Event Trigger ........................109, 115, 120, 188
Timer1/Timer3 Mode Selection ................................ 120
Configuration Bits ............................................................. 195
Context Saving During Interrupts ....................................... 85
Conversion Considerations .............................................. 314
CPFSEQ .......................................................................... 228
CPFSGT ........................................................................... 229
CPFSLT ........................................................................... 229
D
Data EEPROM Memory
Associated Registers ................................................. 69
EEADR Register ........................................................ 65
EECON1 Register ...................................................... 65
EECON2 Register ...................................................... 65
Operation During Code Protect ................................. 68
Protection Against Spurious Write ............................. 68
Reading ..................................................................... 67
Using .......................................................................... 68
Write Verify ................................................................ 68
Writing ........................................................................ 67
Data Memory ..................................................................... 42
General Purpose Registers ....................................... 42
Map for PIC18F242/442 ............................................ 43
Map for PIC18F252/452 ............................................ 44
Special Function Registers ........................................ 42
DAW ................................................................................ 230
DC and AC Characteristics
Graphs and Tables .................................................. 289
DC Characteristics ....................................................261, 265
DCFSNZ .......................................................................... 231
DECF ............................................................................... 230
DECFSZ .......................................................................... 231
Development Support ...................................................... 253
Device Differences ........................................................... 313
Device Overview .................................................................. 7
Features ....................................................................... 7
Direct Addressing ............................................................... 51
Example ..................................................................... 49
E
Electrical Characteristics .................................................. 259
Errata ................................................................................... 5
F
Firmware Instructions ....................................................... 211
FLASH Program Memory ................................................... 55
Associated Registers ................................................. 63
Control Registers ....................................................... 56
Erase Sequence ........................................................ 60
Erasing ....................................................................... 60
Operation During Code Protect ................................. 63
Reading ..................................................................... 59
TABLAT Register ....................................................... 58
Table Pointer ............................................................. 58
Boundaries Based on Operation ........................ 58
Table Pointer Boundaries .......................................... 58
Table Reads and Table Writes .................................. 55
Block Diagrams
Reads from FLASH Program Memory ....... 59
Writing to .................................................................... 61
Protection Against Spurious Writes ................... 63
Unexpected Termination .................................... 63
Write Verify ........................................................ 63
G
General Call Address Support ......................................... 148
GOTO .............................................................................. 232© 2006 Microchip Technology Inc. DS39564C-page 319
PIC18FXX2
I
I/O Ports ............................................................................. 87
I
2C (MSSP Module)
ACK Pulse ................................................................ 139
Read/Write Bit Information (R/W Bit) ....................... 139
I
2C (SSP Module)
ACK Pulse ................................................................ 138
I
2C Master Mode Reception ............................................. 155
I
2C Mode
Clock Stretching ....................................................... 144
I
2C Mode (MSSP Module) ................................................ 134
Registers .................................................................. 134
I
2C Module
ACK Pulse ........................................................ 138, 139
Acknowledge Sequence Timing ............................... 158
Baud Rate Generator ............................................... 151
Bus Collision
Repeated START Condition ............................ 162
START Condition ............................................. 160
Clock Arbitration ....................................................... 152
Effect of a RESET .................................................... 159
General Call Address Support ................................. 148
Master Mode ............................................................ 149
Operation ......................................................... 150
Repeated START Condition Timing ................. 154
Master Mode START Condition ............................... 153
Master Mode Transmission ...................................... 155
Multi-Master Communication, Bus Collision
and Arbitration .................................................. 159
Multi-Master Mode ................................................... 159
Operation ................................................................. 138
Read/Write Bit Information (R/W Bit) ............... 138, 139
Serial Clock (RC3/SCK/SCL) ................................... 139
Slave Mode .............................................................. 138
Addressing ....................................................... 138
Reception ......................................................... 139
Transmission .................................................... 139
Slave Mode Timing (10-bit Reception,
SEN = 0) .......................................................... 142
Slave Mode Timing (10-bit Reception,
SEN = 1) .......................................................... 147
Slave Mode Timing (10-bit Transmission) ................ 143
Slave Mode Timing (7-bit Reception,
SEN = 0) .......................................................... 140
Slave Mode Timing (7-bit Reception,
SEN = 1) .......................................................... 146
Slave Mode Timing (7-bit Transmission) .................. 141
SLEEP Operation ..................................................... 159
STOP Condition Timing ........................................... 158
ICEPIC In-Circuit Emulator .............................................. 254
ID Locations ............................................................. 195, 210
INCF ................................................................................. 232
INCFSZ ............................................................................ 233
In-Circuit Debugger .......................................................... 210
In-Circuit Serial Programming (ICSP) ...................... 195, 210
Indirect Addressing ............................................................ 51
INDF and FSR Registers ........................................... 50
Indirect Addressing Operation ............................................ 51
Indirect File Operand .......................................................... 42
INFSNZ ............................................................................ 233
Instruction Cycle ................................................................. 39
Instruction Flow/Pipelining ................................................. 40
Instruction Format ............................................................ 213
Instruction Set .................................................................. 211
ADDLW .................................................................... 217
ADDWF .................................................................... 217
ADDWFC ................................................................. 218
ANDLW .................................................................... 218
ANDWF .................................................................... 219
BC ............................................................................ 219
BCF ......................................................................... 220
BN ............................................................................ 220
BNC ......................................................................... 221
BNN ......................................................................... 221
BNOV ...................................................................... 222
BNZ ......................................................................... 222
BOV ......................................................................... 225
BRA ......................................................................... 223
BSF .......................................................................... 223
BTFSC ..................................................................... 224
BTFSS ..................................................................... 224
BTG ......................................................................... 225
BZ ............................................................................ 226
CALL ........................................................................ 226
CLRF ....................................................................... 227
CLRWDT ................................................................. 227
COMF ...................................................................... 228
CPFSEQ .................................................................. 228
CPFSGT .................................................................. 229
CPFSLT ................................................................... 229
DAW ........................................................................ 230
DCFSNZ .................................................................. 231
DECF ....................................................................... 230
DECFSZ .................................................................. 231
GOTO ...................................................................... 232
INCF ........................................................................ 232
INCFSZ .................................................................... 233
INFSNZ .................................................................... 233
IORLW ..................................................................... 234
IORWF ..................................................................... 234
LFSR ....................................................................... 235
MOVF ...................................................................... 235
MOVFF .................................................................... 236
MOVLB .................................................................... 236
MOVLW ................................................................... 237
MOVWF ................................................................... 237
MULLW .................................................................... 238
MULWF .................................................................... 238
NEGF ....................................................................... 239
NOP ......................................................................... 239
POP ......................................................................... 240
PUSH ....................................................................... 240
RCALL ..................................................................... 241
RESET ..................................................................... 241
RETFIE .................................................................... 242
RETLW .................................................................... 242
RETURN .................................................................. 243
RLCF ....................................................................... 243
RLNCF ..................................................................... 244
RRCF ....................................................................... 244
RRNCF .................................................................... 245
SETF ....................................................................... 245
SLEEP ..................................................................... 246
SUBFWB ................................................................. 246
SUBLW .................................................................... 247
SUBWF .................................................................... 247
SUBWFB ................................................................. 248
SWAPF .................................................................... 248PIC18FXX2
DS39564C-page 320 © 2006 Microchip Technology Inc.
TBLRD ..................................................................... 249
TBLWT ..................................................................... 250
TSTFSZ ....................................................................251
XORLW ....................................................................251
XORWF ....................................................................252
Summary Table ........................................................ 214
Instructions in Program Memory ........................................ 40
Two-Word Instructions ............................................... 41
INT Interrupt (RB0/INT). See Interrupt Sources
INTCON Register
RBIF Bit ......................................................................90
INTCON Registers ....................................................... 75–77
Inter-Integrated Circuit. See I2C
Interrupt Sources .............................................................. 195
A/D Conversion Complete ........................................ 184
Capture Complete (CCP) ......................................... 119
Compare Complete (CCP) ....................................... 120
INT0 ........................................................................... 85
Interrupt-on-Change (RB7:RB4 ) ............................... 90
PORTB, Interrupt-on-Change .................................... 85
RB0/INT Pin, External ................................................ 85
TMR0 ......................................................................... 85
TMR0 Overflow ........................................................ 105
TMR1 Overflow ................................................ 107, 109
TMR2 to PR2 Match .................................................112
TMR2 to PR2 Match (PWM) ............................ 111, 122
TMR3 Overflow ................................................ 113, 115
USART Receive/Transmit Complete ........................ 165
Interrupts ............................................................................ 73
Logic ........................................................................... 74
Interrupts, Enable Bits
CCP1 Enable (CCP1IE Bit) ...................................... 119
Interrupts, Flag Bits
A/D Converter Flag (ADIF Bit) .................................. 183
CCP1 Flag (CCP1IF Bit) .......................................... 119
CCP1IF Flag (CCP1IF Bit) ....................................... 120
Interrupt-on-Change (RB7:RB4) Flag
(RBIF Bit) ........................................................... 90
IORLW ............................................................................. 234
IORWF ............................................................................. 234
IPR Registers ............................................................... 82–83
K
KEELOQ Evaluation and Programming Tools ................... 256
L
LFSR ................................................................................ 235
Lookup Tables
Computed GOTO ....................................................... 41
Table Reads, Table Writes ......................................... 41
Low Voltage Detect .......................................................... 189
Converter Characteristics ......................................... 267
Effects of a RESET .................................................. 193
Operation ................................................................. 192
Current Consumption ....................................... 193
During SLEEP .................................................. 193
Reference Voltage Set Point ............................193
Typical Application ...................................................189
LVD. See Low Voltage Detect. ......................................... 189
M
Master SSP (MSSP) Module Overview ........................... 125
Master Synchronous Serial Port (MSSP). See MSSP.
Master Synchronous Serial Port. See MSSP
Memory Organization
Data Memory ............................................................. 42
Program Memory ....................................................... 35
Memory Programming Requirements .............................. 268
Migration from Baseline to Enhanced Devices ................ 314
Migration from High-End to Enhanced Devices ............... 315
Migration from Mid-Range to Enhanced Devices ............ 315
MOVF .............................................................................. 235
MOVFF ............................................................................ 236
MOVLB ............................................................................ 236
MOVLW ........................................................................... 237
MOVWF ........................................................................... 237
MPLAB C17 and MPLAB C18 C Compilers ..................... 253
MPLAB ICD In-Circuit Debugger ..................................... 255
MPLAB ICE High Performance Universal In-Circuit
Emulator with MPLAB IDE ....................................... 254
MPLAB Integrated Development
Environment Software ............................................. 253
MPLINK Object Linker/MPLIB Object Librarian ............... 254
MSSP ............................................................................... 125
Control Registers (general) ...................................... 125
Enabling SPI I/O ...................................................... 129
Operation ................................................................. 128
Typical Connection .................................................. 129
MSSP Module
SPI Master Mode ..................................................... 130
SPI Master./Slave Connection ................................. 129
SPI Slave Mode ....................................................... 131
MULLW ............................................................................ 238
MULWF ............................................................................ 238
N
NEGF ............................................................................... 239
NOP ................................................................................. 239
O
Opcode Field Descriptions ............................................... 212
OPTION_REG Register
PSA Bit .................................................................... 105
T0CS Bit .................................................................. 105
T0PS2:T0PS0 Bits ................................................... 105
T0SE Bit ................................................................... 105
Oscillator Configuration ...................................................... 17
EC .............................................................................. 17
ECIO .......................................................................... 17
HS .............................................................................. 17
HS + PLL ................................................................... 17
LP .............................................................................. 17
RC .............................................................................. 17
RCIO .......................................................................... 17
XT .............................................................................. 17
Oscillator Selection .......................................................... 195
Oscillator, Timer1 ..............................................107, 109, 115
Oscillator, Timer3 ............................................................. 113
Oscillator, WDT ................................................................ 203© 2006 Microchip Technology Inc. DS39564C-page 321
PIC18FXX2
P
Packaging ........................................................................ 305
Details ...................................................................... 307
Marking Information ................................................. 305
Parallel Slave Port
PORTD .................................................................... 100
Parallel Slave Port (PSP) ........................................... 95, 100
Associated Registers ............................................... 101
RE0/RD/AN5 Pin ................................................ 99, 100
RE1/WR/AN6 Pin ............................................... 99, 100
RE2/CS/AN7 Pin ................................................ 99, 100
Select (PSPMODE Bit) ...................................... 95, 100
PIC18F2X2 Pin Functions
MCLR/VPP .................................................................. 10
OSC1/CLKI ................................................................ 10
OSC2/CLKO/RA6 ...................................................... 10
RA0/AN0 .................................................................... 10
RA1/AN1 .................................................................... 10
RA2/AN2/VREF- .......................................................... 10
RA3/AN3/VREF+ ......................................................... 10
RA4/T0CKI ................................................................. 10
RA5/AN4/SS/LVDIN ................................................... 10
RB0/INT0 ................................................................... 11
RB1/INT1 ................................................................... 11
RB2/INT2 ................................................................... 11
RB3/CCP2 ................................................................. 11
RB4 ............................................................................ 11
RB5/PGM ................................................................... 11
RB6/PGC ................................................................... 11
RB7/PGD ................................................................... 11
RC0/T1OSO/T1CKI ................................................... 12
RC1/T1OSI/CCP2 ...................................................... 12
RC2/CCP1 ................................................................. 12
RC3/SCK/SCL ........................................................... 12
RC4/SDI/SDA ............................................................ 12
RC5/SDO ................................................................... 12
RC6/TX/CK ................................................................ 12
RC7/RX/DT ................................................................ 12
VDD ............................................................................. 12
VSS ............................................................................. 12
PIC18F4X2 Pin Functions
MCLR/VPP .................................................................. 13
OSC1/CLKI ................................................................ 13
OSC2/CLKO .............................................................. 13
RA0/AN0 .................................................................... 13
RA1/AN1 .................................................................... 13
RA2/AN2/VREF- .......................................................... 13
RA3/AN3/VREF+ ......................................................... 13
RA4/T0CKI ................................................................. 13
RA5/AN4/SS/LVDIN ................................................... 13
RB0/INT ..................................................................... 14
RB1 ............................................................................ 14
RB2 ............................................................................ 14
RB3 ............................................................................ 14
RB4 ............................................................................ 14
RB5/PGM ................................................................... 14
RB6/PGC ................................................................... 14
RB7/PGD ................................................................... 14
RC0/T1OSO/T1CKI ................................................... 15
RC1/T1OSI/CCP2 ...................................................... 15
RC2/CCP1 ................................................................. 15
RC3/SCK/SCL ........................................................... 15
RC4/SDI/SDA ............................................................ 15
RC5/SDO ................................................................... 15
RC6/TX/CK ................................................................ 15
RC7/RX/DT ................................................................ 15
RD0/PSP0 ................................................................. 16
RD1/PSP1 ................................................................. 16
RD2/PSP2 ................................................................. 16
RD3/PSP3 ................................................................. 16
RD4/PSP4 ................................................................. 16
RD5/PSP5 ................................................................. 16
RD6/PSP6 ................................................................. 16
RD7/PSP7 ................................................................. 16
RE0/RD/AN5 .............................................................. 16
RE1/WR/AN6 ............................................................. 16
RE2/CS/AN7 .............................................................. 16
VDD ............................................................................ 16
VSS ............................................................................ 16
PIC18FXX2 Voltage-Frequency Graph
(Industrial) ................................................................ 260
PIC18LFXX2 Voltage-Frequency Graph
(Industrial) ................................................................ 260
PICDEM 1 Low Cost PICmicro
Demonstration Board ............................................... 255
PICDEM 17 Demonstration Board ................................... 256
PICDEM 2 Low Cost PIC16CXX
Demonstration Board ............................................... 255
PICDEM 3 Low Cost PIC16CXXX
Demonstration Board ............................................... 256
PICSTART Plus Entry Level Development
Programmer ............................................................. 255
PIE Registers ................................................................80–81
Pinout I/O Descriptions
PIC18F2X2 ................................................................ 10
PIR Registers ................................................................78–79
PLL Lock Time-out ............................................................. 26
Pointer, FSR ...................................................................... 50
POP ................................................................................. 240
POR. See Power-on Reset
PORTA
Associated Registers ................................................. 89
LATA Register ........................................................... 87
PORTA Register ........................................................ 87
TRISA Register .......................................................... 87
PORTB
Associated Registers ................................................. 92
LATB Register ........................................................... 90
PORTB Register ........................................................ 90
RB0/INT Pin, External ................................................ 85
RB7:RB4 Interrupt-on-Change Flag (RBIF Bit) .......... 90
TRISB Register .......................................................... 90
PORTC
Associated Registers ................................................. 94
LATC Register ........................................................... 93
PORTC Register ........................................................ 93
RC3/SCK/SCL Pin ................................................... 139
RC7/RX/DT Pin ........................................................ 168
TRISC Register ...................................................93, 165
PORTD
Associated Registers ................................................. 96
LATD Register ........................................................... 95
Parallel Slave Port (PSP) Function ............................ 95
PORTD Register ........................................................ 95
TRISD Register .......................................................... 95PIC18FXX2
DS39564C-page 322 © 2006 Microchip Technology Inc.
PORTE
Analog Port Pins ................................................ 99, 100
Associated Registers .................................................99
LATE Register ............................................................ 97
PORTE Register ........................................................ 97
PSP Mode Select (PSPMODE Bit) .................... 95, 100
RE0/RD/AN5 Pin ................................................ 99, 100
RE1/WR/AN6 Pin ............................................... 99, 100
RE2/CS/AN7 Pin ................................................ 99, 100
TRISE Register .......................................................... 97
Postscaler, WDT
Assignment (PSA Bit) ...............................................105
Rate Select (T0PS2:T0PS0 Bits) ............................. 105
Switching Between Timer0 and WDT ...................... 105
Power-down Mode. See SLEEP
Power-on Reset (POR) ...................................................... 26
Oscillator Start-up Timer (OST) ................................. 26
Power-up Timer (PWRT) ............................................ 26
Prescaler, Capture ........................................................... 119
Prescaler, Timer0 ............................................................. 105
Assignment (PSA Bit) ...............................................105
Rate Select (T0PS2:T0PS0 Bits) ............................. 105
Switching Between Timer0 and WDT ...................... 105
Prescaler, Timer2 ............................................................. 122
PRO MATE II Universal Device Programmer ................... 255
Product Identification System ........................................... 327
Program Counter
PCL Register .............................................................. 39
PCLATH Register ....................................................... 39
PCLATU Register ....................................................... 39
Program Memory
Interrupt Vector .......................................................... 35
Map and Stack for PIC18F442/242 ............................36
Map and Stack for PIC18F452/252 ............................36
RESET Vector ............................................................ 35
Program Verification and Code Protection ....................... 207
Associated Registers ...............................................207
Programming, Device Instructions ................................... 211
PSP.See Parallel Slave Port.
Pulse Width Modulation. See PWM (CCP Module).
PUSH ............................................................................... 240
PWM (CCP Module) ......................................................... 122
Associated Registers ...............................................123
CCPR1H:CCPR1L Registers ................................... 122
Duty Cycle ................................................................ 122
Example Frequencies/Resolutions ........................... 123
Period ....................................................................... 122
Setup for PWM Operation ........................................ 123
TMR2 to PR2 Match ......................................... 111, 122
Q
Q Clock ............................................................................ 122
R
RAM. See Data Memory
RC Oscillator ......................................................................18
RCALL .............................................................................. 241
RCSTA Register
SPEN Bit .................................................................. 165
Register File ....................................................................... 42
Registers
ADCON0 (A/D Control 0) ......................................... 181
ADCON1 (A/D Control 1) ......................................... 182
CCP1CON and CCP2CON
(Capture/Compare/PWM Control) ................... 117
CONFIG1H (Configuration 1 High) .......................... 196
CONFIG2H (Configuration 2 High) .......................... 197
CONFIG2L (Configuration 2 Low) ........................... 197
CONFIG3H (Configuration 3 High) .......................... 198
CONFIG4L (Configuration 4 Low) ........................... 198
CONFIG5H (Configuration 5 High) .......................... 199
CONFIG5L (Configuration 5 Low) ........................... 199
CONFIG6H (Configuration 6 High) .......................... 200
CONFIG6L (Configuration 6 Low) ........................... 200
CONFIG7H (Configuration 7 High) .......................... 201
CONFIG7L (Configuration 7 Low) ........................... 201
DEVID1 (Device ID Register 1) ............................... 202
DEVID2 (Device ID Register 2) ............................... 202
EECON1 (Data EEPROM Control 1) ....................57, 66
File Summary ........................................................46–48
INTCON (Interrupt Control) ........................................ 75
INTCON2 (Interrupt Control 2) ................................... 76
INTCON3 (Interrupt Control 3) ................................... 77
IPR1 (Peripheral Interrupt Priority 1) ......................... 82
IPR2 (Peripheral Interrupt Priority 2) ......................... 83
LVDCON (LVD Control) ........................................... 191
OSCCON (Oscillator Control) .................................... 21
PIE1 (Peripheral Interrupt Enable 1) .......................... 80
PIE2 (Peripheral Interrupt Enable 2) .......................... 81
PIR1 (Peripheral Interrupt Request 1) ....................... 78
PIR2 (Peripheral Interrupt Request 2) ....................... 79
RCON (Register Control) ........................................... 84
RCON (RESET Control) ............................................ 53
RCSTA (Receive Status and Control) ..................... 167
SSPCON1 (MSSP Control 1)
I
2C Mode ......................................................... 136
SPI Mode ......................................................... 127
SSPCON2 (MSSP Control 2)
I
2C Mode ......................................................... 137
SSPSTAT (MSSP Status)
I
2C Mode ......................................................... 135
SPI Mode ......................................................... 126
STATUS ..................................................................... 52
STKPTR (Stack Pointer) ............................................ 38
T0CON (Timer0 Control) ......................................... 103
T1CON (Timer 1 Control) ........................................ 107
T2CON (Timer 2 Control) ........................................ 111
T3CON (Timer3 Control) ......................................... 113
TRISE ........................................................................ 98
TXSTA (Transmit Status and Control) ..................... 166
WDTCON (Watchdog Timer Control) ...................... 203
RESET ................................................................25, 195, 241
Brown-out Reset (BOR) ........................................... 195
MCLR Reset (During SLEEP) .................................... 25
MCLR Reset (Normal Operation) .............................. 25
Oscillator Start-up Timer (OST) ............................... 195
Power-on Reset (POR) .......................................25, 195
Power-up Timer (PWRT) ......................................... 195
Programmable Brown-out Reset (BOR) .................... 25
RESET Instruction ..................................................... 25
Stack Full Reset ......................................................... 25
Stack Underflow Reset .............................................. 25
Watchdog Timer (WDT) Reset .................................. 25© 2006 Microchip Technology Inc. DS39564C-page 323
PIC18FXX2
RETFIE ............................................................................ 242
RETLW ............................................................................. 242
RETURN .......................................................................... 243
Revision History ............................................................... 313
RLCF ................................................................................ 243
RLNCF ............................................................................. 244
RRCF ............................................................................... 244
RRNCF ............................................................................. 245
S
SCI. See USART
SCK .................................................................................. 125
SDI ................................................................................... 125
SDO ................................................................................. 125
Serial Clock, SCK ............................................................. 125
Serial Communication Interface. See USART
Serial Data In, SDI ........................................................... 125
Serial Data Out, SDO ....................................................... 125
Serial Peripheral Interface. See SPI
SETF ................................................................................ 245
Slave Select Synchronization ........................................... 131
Slave Select, SS .............................................................. 125
SLEEP ...............................................................195, 205, 246
Software Simulator (MPLAB SIM) .................................... 254
Special Event Trigger. See Compare
Special Features of the CPU ............................................ 195
Configuration Registers ................................... 196–201
Special Function Registers ................................................ 42
Map ............................................................................ 45
SPI
Master Mode ............................................................ 130
Serial Clock .............................................................. 125
Serial Data In ........................................................... 125
Serial Data Out ........................................................ 125
Slave Select ............................................................. 125
SPI Clock ................................................................. 130
SPI Mode ................................................................. 125
SPI Master/Slave Connection .......................................... 129
SPI Module
Associated Registers ............................................... 133
Bus Mode Compatibility ........................................... 133
Effects of a RESET .................................................. 133
Master/Slave Connection ......................................... 129
Slave Mode .............................................................. 131
Slave Select Synchronization .................................. 131
Slave Synch Timing ................................................. 131
SLEEP Operation ..................................................... 133
SS .................................................................................... 125
SSP
I
2C Mode. See I2C
SPI Mode ................................................................. 125
SPI Mode. See SPI
SSPBUF Register .................................................... 130
SSPSR Register ...................................................... 130
TMR2 Output for Clock Shift ............................ 111, 112
SSPOV Status Flag .......................................................... 155
SSPSTAT Register
R/W Bit ............................................................. 138, 139
Status Bits
Significance and the Initialization Condition
for RCON Register ............................................. 27
SUBFWB .......................................................................... 246
SUBLW ............................................................................ 247
SUBWF ............................................................................ 247
SUBWFB .......................................................................... 248
SWAPF ............................................................................ 248
T
TABLAT Register ............................................................... 58
Table Pointer Operations (table) ........................................ 58
TBLPTR Register ............................................................... 58
TBLRD ............................................................................. 249
TBLWT ............................................................................. 250
Time-out Sequence ........................................................... 26
Time-out in Various Situations ................................... 27
Timer0 .............................................................................. 103
16-bit Mode Timer Reads and Writes ...................... 105
Associated Registers ............................................... 105
Clock Source Edge Select (T0SE Bit) ..................... 105
Clock Source Select (T0CS Bit) ............................... 105
Operation ................................................................. 105
Overflow Interrupt .................................................... 105
Prescaler. See Prescaler, Timer0
Timer1 .............................................................................. 107
16-bit Read/Write Mode ........................................... 109
Associated Registers ............................................... 110
Operation ................................................................. 108
Oscillator ...........................................................107, 109
Overflow Interrupt .............................................107, 109
Special Event Trigger (CCP) ............................109, 120
TMR1H Register ...................................................... 107
TMR1L Register ....................................................... 107
Timer2 .............................................................................. 111
Associated Registers ............................................... 112
Operation ................................................................. 111
Postscaler. See Postscaler, Timer2
PR2 Register ....................................................111, 122
Prescaler. See Prescaler, Timer2
SSP Clock Shift ................................................111, 112
TMR2 Register ......................................................... 111
TMR2 to PR2 Match Interrupt ...................111, 112, 122
Timer3 .............................................................................. 113
Associated Registers ............................................... 115
Operation ................................................................. 114
Oscillator ...........................................................113, 115
Overflow Interrupt .............................................113, 115
Special Event Trigger (CCP) ................................... 115
TMR3H Register ...................................................... 113
TMR3L Register ....................................................... 113
Timing Diagrams
Bus Collision
Transmit and Acknowledge ..................... 159
A/D Conversion ........................................................ 287
Acknowledge Sequence .......................................... 158
Baud Rate Generator with Clock Arbitration ............ 152
BRG Reset Due to SDA Arbitration During
START Condition ............................................. 161
Brown-out Reset (BOR) ........................................... 274
Bus Collision
Start Condition (SDA Only) .............................. 160
Bus Collision During a Repeated
START Condition (Case 1) .............................. 162
Bus Collision During a Repeated
START Condition (Case 2) .............................. 162
Bus Collision During a START Condition
(SCL = 0) ......................................................... 161
Bus Collision During a STOP Condition
(Case 1) ........................................................... 163
Bus Collision During a STOP Condition
(Case 2) ........................................................... 163
Capture/Compare/PWM (CCP1 and CCP2) ............ 276
CLKO and I/O .......................................................... 272
Clock Synchronization ............................................. 145PIC18FXX2
DS39564C-page 324 © 2006 Microchip Technology Inc.
Example SPI Master Mode (CKE = 0) ..................... 278
Example SPI Master Mode (CKE = 1) ..................... 279
Example SPI Slave Mode (CKE = 0) ....................... 280
Example SPI Slave Mode (CKE = 1) ....................... 281
External Clock (All Modes except PLL) .................... 271
First START Bit Timing ............................................ 153
I
2C Bus Data ............................................................ 282
I
2C Bus START/STOP Bits ...................................... 282
I
2C Master Mode (Reception, 7-bit Address) ........... 157
I
2C Master Mode (Transmission,
7 or 10-bit Address) ......................................... 156
I
2C Slave Mode Timing (10-bit Reception,
SEN = 0) .......................................................... 142
I
2C Slave Mode Timing (10-bit Transmission) .........143
I
2C Slave Mode Timing (7-bit Reception,
SEN = 0) .......................................................... 140
I
2C Slave Mode Timing (7-bit Reception,
SEN = 1) .................................................. 146, 147
I
2C Slave Mode Timing (7-bit Transmission) ........... 141
Low Voltage Detect .................................................. 192
Master SSP I2C Bus Data ........................................ 284
Master SSP I2C Bus START/STOP Bits .................. 284
Parallel Slave Port (PIC18F4X2) ..............................277
Parallel Slave Port (Read) ........................................ 101
Parallel Slave Port (Write) ........................................ 100
PWM Output ............................................................. 122
Repeat START Condition ......................................... 154
RESET, Watchdog Timer (WDT),
Oscillator Start-up Timer (OST) and
Power-up Timer (PWRT) ................................. 273
Slave Synchronization .............................................. 131
Slaver Mode General Call Address Sequence
(7 or 10-bit Address Mode) ..............................148
Slow Rise Time (MCLR Tied to VDD) ......................... 33
SPI Mode (Master Mode) ......................................... 130
SPI Mode (Slave Mode with CKE = 0) ..................... 132
SPI Mode (Slave Mode with CKE = 1) ..................... 132
Stop Condition Receive or Transmit Mode .............. 158
Time-out Sequence on POR w/PLL Enabled
(MCLR Tied to VDD) ........................................... 33
Time-out Sequence on Power-up
(MCLR Not Tied to VDD)
Case 1 ................................................................ 32
Case 2 ................................................................ 32
Time-out Sequence on Power-up
(MCLR Tied to VDD) ........................................... 32
Timer0 and Timer1 External Clock ........................... 275
Timing for Transition Between Timer1 and
OSC1 (HS with PLL) .......................................... 23
Transition Between Timer1 and OSC1
(HS, XT, LP) ....................................................... 22
Transition Between Timer1 and OSC1
(RC, EC) ............................................................ 23
Transition from OSC1 to Timer1 Oscillator ................ 22
USART Asynchronous Master Transmission ........... 173
USART Asynchronous Master Transmission
(Back to Back) .................................................. 173
USART Asynchronous Reception ............................175
USART Synchronous Receive (Master/Slave) .........286
USART Synchronous Reception
(Master Mode, SREN) ...................................... 178
USART Synchronous Transmission ......................... 177
USART Synchronous Transmission
(Master/Slave) .................................................. 286
USART Synchronous Transmission
(Through TXEN) .............................................. 177
Wake-up from SLEEP via Interrupt .......................... 206
Timing Diagrams Requirements
Master SSP I2C Bus START/STOP Bits .................. 284
Timing Requirements
A/D Conversion ........................................................ 288
Capture/Compare/PWM (CCP1 and CCP2) ............ 276
CLKO and I/O .......................................................... 273
Example SPI Mode (Master Mode, CKE = 0) .......... 278
Example SPI Mode (Master Mode, CKE = 1) .......... 279
Example SPI Mode (Slave Mode, CKE = 0) ............ 280
Example SPI Slave Mode (CKE = 1) ....................... 281
External Clock .......................................................... 271
I
2C Bus Data (Slave Mode) ..................................... 283
Master SSP I2C Bus Data ........................................ 285
Parallel Slave Port (PIC18F4X2) ............................. 277
RESET, Watchdog Timer, Oscillator Start-up
Timer, Power-up Timer and
Brown-out Reset Requirements ....................... 274
Timer0 and Timer1 External Clock .......................... 275
USART Synchronous Receive ................................. 286
USART Synchronous Transmission ........................ 286
Timing Specifications
PLL Clock ................................................................ 272
TRISE Register
PSPMODE Bit .....................................................95, 100
TSTFSZ ........................................................................... 251
Two-Word Instructions
Example Cases .......................................................... 41
TXSTA Register
BRGH Bit ................................................................. 168
U
Universal Synchronous Asynchronous
Receiver Transmitter. See USART
USART ............................................................................. 165
Asynchronous Mode ................................................ 172
Associated Registers, Receive ........................ 175
Associated Registers, Transmit ....................... 173
Receiver .......................................................... 174
Transmitter ....................................................... 172
Baud Rate Generator (BRG) ................................... 168
Associated Registers ....................................... 168
Baud Rate Error, Calculating ........................... 168
Baud Rate Formula .......................................... 168
Baud Rates for Asynchronous Mode
(BRGH = 0) .............................................. 170
Baud Rates for Asynchronous Mode
(BRGH = 1) .............................................. 171
Baud Rates for Synchronous Mode ................. 169
High Baud Rate Select (BRGH Bit) ................. 168
Sampling .......................................................... 168
Serial Port Enable (SPEN Bit) ................................. 165
Synchronous Master Mode ...................................... 176
Associated Registers, Reception ..................... 178
Associated Registers, Transmit ....................... 176
Reception ........................................................ 178
Transmission ................................................... 176
Synchronous Slave Mode ........................................ 179
Associated Registers, Receive ........................ 180
Associated Registers, Transmit ....................... 179
Reception ........................................................ 180
Transmission ................................................... 179© 2006 Microchip Technology Inc. DS39564C-page 325
PIC18FXX2
W
Wake-up from SLEEP .............................................. 195, 205
Using Interrupts ........................................................ 205
Watchdog Timer (WDT) ........................................... 195, 203
Associated Registers ............................................... 204
Control Register ....................................................... 203
Postscaler ........................................................ 203, 204
Programming Considerations .................................. 203
RC Oscillator ............................................................ 203
Time-out Period ....................................................... 203
WCOL .............................................................................. 153
WCOL Status Flag ............................................153, 155, 158
WWW, On-Line Support ....................................................... 5
X
XORLW ............................................................................ 251
XORWF ........................................................................... 252PIC18FXX2
DS39564C-page 326 © 2006 Microchip Technology Inc.
NOTES:© 2006 Microchip Technology Inc. DS39564C-page 327
PIC18FXX2
THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at
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Customers should contact their distributor,
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support. Local sales offices are also available to help
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included in the back of this document.
Technical support is available through the web site
at: http://support.microchip.comPIC18FXX2
DS39564C-page 328 Advance Information © 2006 Microchip Technology Inc.
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product.
If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
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PIC18FXX2 DS39564C
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?© 2006 Microchip Technology Inc. DS39564C-page 329
PIC18FXX2
PIC18FXX2 PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. − X /XX XXX
Temperature Package Pattern
Range
Device
Device PIC18FXX2(1), PIC18FXX2T(2);
VDD range 4.2V to 5.5V
PIC18LFXX2(1), PIC18LFXX2T(2);
VDD range 2.5V to 5.5V
Temperature
Range
I = -40°C to +85°C (Industrial)
E = -40°C to +125°C (Extended)
Package PT = TQFP (Thin Quad Flatpack)
SO = SOIC
SP = Skinny Plastic DIP
P = PDIP
L = PLCC
Pattern QTP, SQTP, Code or Special Requirements
(blank otherwise)
Examples:
a) PIC18LF452 - I/P 301 = Industrial temp.,
PDIP package, Extended VDD limits,
QTP pattern #301.
b) PIC18LF242 - I/SO = Industrial temp.,
SOIC package, Extended VDD limits.
c) PIC18F442 - E/P = Extended temp.,
PDIP package, normal VDD limits.
Note 1: F = Standard Voltage range
LF = Wide Voltage Range
2: T = in tape and reel - SOIC,
PLCC, and TQFP
packages only.DS39564C-page 330 © 2006 Microchip Technology Inc.
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WORLDWIDE SALES AND SERVICE
08/29/06
9596C–AT42–05/2013
Features
Configurations:
Comms mode
Standalone mode
Number of Keys:
Comms mode: 1 – 7 keys (or 1 – 6 keys plus a Guard Channel)
Standalone mode: 1 – 4 keys plus a fixed Guard Channel on key 0
Number of I/O Lines:
Standalone mode: 5 outputs
Technology:
Patented spread-spectrum charge-transfer
Key Outline Sizes:
6 mm x 6 mm or larger (panel thickness dependent); widely different sizes and
shapes possible
Layers Required:
One
Electrode Materials:
Etched copper; Silver; Carbon; Indium Tin Oxide (ITO)
Panel Materials:
Plastic; Glass; Composites; Painted surfaces (low particle density metallic
paints possible
Panel Thickness:
Up to 10 mm glass; Up to 5 mm plastic (electrode size dependent)
Key Sensitivity:
Comms mode: individually settable via simple commands over I2
C-compatible
interface
Standalone mode: settings are fixed
Interface:
I
2
C-compatible slave mode (400 kHz). Discrete detection outputs
Signal Processing:
Self-calibration
Auto drift compensation
Noise filtering
Adjacent Key Suppression® (AKS®) – up to three groups possible
Power:
1.8 V – 5.5 V
Package:
14-pin SOIC RoHS compliant IC
20-pin VQFN RoHS compliant IC
Atmel AT42QT1070
Seven-channel QTouch® Touch Sensor IC
DATASHEETAT42QT1070 [DATASHEET] 2
9596C–AT42–05/2013
1. Pinouts and Schematics
1.1 Pinout Configuration – Comms Mode (14-pin SOIC)
1.2 Pinout Configuration – Standalone Mode (14-pin SOIC)
VDD
MODE (Vss)
RESET
SDA
CHANGE
KEY2
KEY1
KEY0
1
2
3
4
5
6
7 8
9
10
11
12
13
14
QT1070
SCL
KEY6
KEY3
VSS
KEY5
KEY4
VDD
MODE (Vdd)
RESET
OUT0
OUT4
KEY2
KEY1
KEY0
1
2
3
4
5
6
7 8
9
10
11
12
13
14
QT1070
OUT3
OUT2
KEY3
VSS
OUT1
KEY4AT42QT1070 [DATASHEET] 3 9596C–AT42–05/2013
1.3 Pinout Configuration – Comms Mode (20-pin VQFN)
1.4 Pinout Configuration – Standalone Mode (20-pin VQFN) NCNC VSS VDDNC
KEY4
KEY3
KEY2
KEY1
KEY0 MODE (Vss)
SDA
1
2
3
4
5 11
12
13
14
15
20 19 18 17 16
6 7 8 9 10
QT1070 RESET
CHANGE
SCL
NC
NC
NC
KEY5
KEY6
NC
NC
VSS
VDD
NC
KEY4
KEY3
KEY2
KEY1
KEY0 MODE (Vdd)
OUT0
1
2
3
4
5 11
12
13
14
15
20 19 18 17 16
6 7 8 9 10
QT1070 RESET
OUT4
OUT3
NC
NC
NC
OUT1
OUT2AT42QT1070 [DATASHEET] 4
9596C–AT42–05/2013
1.5 Pin Descriptions
I Input only O Output only, push-pull
OD Open drain output P Ground or power
Table 1-1. Pin Listings (14-pin SOIC)
Pin
Name
(Comms
Mode)
Name
(Standalone
Mode) Type Description
If Unused,
Connect
To...
1 VDD VDD P Power –
2 MODE MODE I
Mode selection pin
Comms Mode – connect to Vss
Standalone Mode – connect to Vdd
–
3 SDA OUT0 OD
Comms Mode – I2
C data line
Standalone Mode – open drain output for guard
channel
Open
4 RESET RESET I RESET – has internal pull-up 60 k resistor Open
5 CHANGE OUT4 OD
CHANGE line for controlling the communications
flow
Comms Mode – connect to CHANGE line
Standalone Mode – connect to output
Open
6 SCL OUT3 OD
Comms Mode – connect to I
2
C clock
Standalone Mode – connect to output Open
7 KEY6 OUT2 O/OD
Comms Mode – connect to Key 6
Standalone Mode – connect to output Open
8 KEY5 OUT1 O/OD
Comms Mode – connect to Key 5
Standalone Mode – connect to output Open
9 KEY4 KEY4 O Key 4 Open
10 KEY3 KEY3 O Key 3 Open
11 KEY2 KEY2 O Key 2 Open
12 KEY1 KEY1 O Key 1 Open
13 KEY0 KEY0 O Key 0 Open
14 VSS VSS P Ground –AT42QT1070 [DATASHEET] 5 9596C–AT42–05/2013
I Input only O Output only, push-pull
OD Open drain output P Ground or power
Table 1-2. Pin Listings (20-pin VQFN)
Pin
Name
(Comms
Mode)
Name
(Standalone
Mode) Type Description
If Unused,
Connect
To...
1 KEY4 KEY4 O Key 4 Open
2 KEY3 KEY3 O Key 3 Open
3 KEY2 KEY2 O Key 2 Open
4 KEY1 KEY1 O Key 1 Open
5 KEY0 KEY0 O Key 0 Open
6 NC NC – Not connected –
7 NC NC – Not connected –
8 VSS VSS P Ground –
9 VDD VDD P Power –
10 NC NC – Not connected –
11 MODE MODE I
Mode selection pin
Comms Mode – connect to Vss
Standalone Mode – connect to Vdd
–
12 SDA OUT0 OD
Comms Mode – I2
C data line
Standalone Mode – open drain output for
guard channel
Open
13 RESET RESET I RESET – has internal pull-up 60 k resistor Open
14 CHANGE OUT4 OD
CHANGE line for controlling the communications
flow
Comms Mode – connect to CHANGE line
Standalone Mode – connects to output
Open
15 SCL OUT3 OD
Comms Mode – connect to I
2
C clock
Standalone Mode – connect to output Open
16 KEY6 OUT2 O/OD
Comms Mode – connect to Key 6
Standalone Mode – connect to output Open
17 KEY5 OUT1 O/OD
Comms Mode – connect to Key 5
Standalone Mode – connect to output Open
18 NC NC – Not connected –
19 NC NC – Not connected –
20 NC NC – Not connected –AT42QT1070 [DATASHEET] 6
9596C–AT42–05/2013
1.6 Schematics
Figure 1-1. Typical Circuit – Comms (14-pin SOIC)
Figure 1-2. Typical Circuit – Standalone (14-pin SOIC)
Rs6
C1
K4
RSCL
Rs5
Rs4
Rs3
Rs2
Rs1
K3
K2
K1
1
QT1070
MODE (Vss)
2
SDA 3
RESET 4
CHANGE 5
SCL 6
KEY6 7
KEY5 8
KEY4 9
KEY3 10
KEY2 11
KEY1 12
KEY0 13
14
Vss
Rs0 K0
Vss
Vdd
CHANGE
SDA
RESET
K5
K6
Vdd
SCL
Vdd
Vss
RSDA
Vdd
RCHG RRST
ROUT2
C1
K4
ROUT3
ROUT1
Rs4
Rs3
Rs2
Rs1
K3
K2
K1
1
OUT0 3
RESET 4
OUT4 5
OUT3 6
OUT2 7
OUT1 8
KEY4 9
KEY3 10
KEY2 11
KEY1 12
KEY0 13
Vss
Rs0 K0
Vss
ROUT4
Vdd
RESET
COUT1
COUT2
COUT3
Vss
COUT4
COUT0
14
Vss
QT1070
Vdd
Vss
OUTPUTS
OUTPUTS
ROUT0
MODE (Vdd)
2
COUT1, 2 3 and are optional
COUT0 4 and are optional
R1
VddAT42QT1070 [DATASHEET] 7 9596C–AT42–05/2013
Figure 1-3. Typical Circuit – Comms (20-pin VQFN)
Figure 1-4. Typical Circuit – Standalone (20-pin VQFN)
For component values in Figure 1-1, 1-2, 1-3, and 1-4, check the following sections:
Section 3.1 on page 12: Series resistors (Rs0 – Rs6 for comms mode and Rs0 – Rs4 for standalone mode)
Section 3.2 on page 12: LED traces
Section 3.4 on page 12: Power Supply (voltage levels)
Section 4.4 on page 14: SDA, SCL pull-up resistors
Rs6
C1
K4
Rs5
Rs4
Rs3
Rs2
Rs1
K3
K2
K1
9
QT1070
SCL 15
SDA 12
RESET 13
CHANGE 14 KEY6 16
KEY5 17
KEY4 1
KEY3 2
KEY2 3
KEY1 4
KEY0 5
8
Vss
Rs0 K0
Vss
Vdd
K5
K6
RSCL
Vdd Vdd
Vss
11
MODE (Vss)
N/C
N/C 18
N/C 19
N/C 20
N/C 7
N/C 6
10
CHANGE
SDA
RESET
RSDA
Vdd
RCHG RRST
RsOUT2
K4
RsOUT3
RLOUT1
Rs4
Rs3
Rs2
Rs1
K3
K2
K1
OUT0 12
RESET 13
OUT4 14
OUT3 15
OUT2 16
OUT1 17
KEY4 1
KEY3 2
KEY2 3
KEY1
KEY0 5
Vss
Rs0 K0
ROUT4
RESET
COUT1
COUT2
COUT3
Vss
COUT4
COUT0
8
QT1070
Vss
OUTPUTS
OUTPUTS
N/C
N/C 18
N/C 19
N/C 20
N/C 7
N/C 6
10
4
ROUT0
Vss
C1
9 Vss
Vdd
MODE (Vdd) Vdd
11
COUT1, 2 3 and are optional
COUT0 4 and are optional
R1
VddAT42QT1070 [DATASHEET] 8
9596C–AT42–05/2013
2. Overview
2.1 Introduction
The AT42QT1070 (QT1070) is a digital burst mode charge-transfer (QT™) capacitive sensor driver. The device can
sense from one to seven keys, dependent on mode.
The QT1070 includes all signal processing functions necessary to provide stable sensing under a wide variety of
changing conditions, and the outputs are fully debounced. Only a few external parts are required for operation and
no external Cs capacitors are required.
The QT1070 modulates its bursts in a spread-spectrum fashion in order to heavily suppress the effects of external
noise, and to suppress RF emissions. The QT1070 uses a dual-pulse method of acquisition. This provides greater
noise immunity and eliminates the need for external sampling capacitors, allowing touch sensing using a single pin.
2.2 Modes
2.2.1 Comms Mode
The QT1070 can operate in comms mode where a host can communicate with the device via an I2
C bus. This allows
the user to configure settings for Threshold, Adjacent Key Suppression (AKS), Detect Integrator, Low Power (LP)
Mode, Guard Channel and Max Time On for keys.
2.2.2 Standalone Mode
The QT1070 can operate in a standalone mode where an I2
C interface is not required. To enter standalone mode,
connect the Mode pin to Vdd before powering up the QT1070.
In standalone mode, the start-up values are hard coded in firmware and cannot be changed. The default start-up
values are used. This means that key detection is reported via their respective IOs. The Guard channel feature is
automatically implemented on key 0 in standalone mode. This means that this channel gets priority over all other
keys going into touch.
2.3 Keys
Dependent on mode, the QT1070 can have a minimum of one key and a maximum of seven keys. These can be
constructed in different shapes and sizes. See “Features” on page 1 for the recommended dimensions.
Comms mode – 1 to 7 keys (or 1 to 6 keys plus Guard Channel)
Standalone mode – 1 to 4 keys plus a Guard Channel
Unused keys should be disabled by setting the averaging factor to zero (see Section 5.9 on page 18).
The status register can be read to determine the touch status of the corresponding key. It is recommended using the
open-drain CHANGE line to detect when a change of status has occurred.
2.4 Input/Output (IO) Lines
There are no IO lines in comms mode.
In Standalone mode pins OUT0 – OUT4 can be used as open drain outputs for driving LEDs.
2.5 Acquisition/Low Power Mode (LP)
There are 255 different acquisition times possible. These are controlled via the LP mode byte (see Section 5.11 on
page 19) which can be written to via I2
C communication.
LP mode controls the intervals between acquisition measurements. Longer intervals consume lower power but have
an increased response time. During calibration, touch and during the detect integrator (DI) period, the LP mode is
temporarily set to LP mode 1 for a faster response.AT42QT1070 [DATASHEET] 9 9596C–AT42–05/2013
The QT1070 operation is based on a fixed cycle time of approximately 8 ms. The LP mode setting indicates how
many of these periods exist per measurement cycle. For example, If LP mode = 1, there is an acquisition every cycle
(8 ms). If LP mode = 3, there is an acquisition every 3 cycles (24 ms). If a high Averaging Factor (see Section 5.9 on
page 18) setting is selected then the acquisition time may exceed 8 ms.
LP settings above mode 32 (256 ms) result in slower thermal drift compensation and should be avoided in
applications where fast thermal transients occur.
2.6 Adjacent Key Suppression (AKS) Technology
The device includes the Atmel-patented Adjacent Key Suppression (AKS) technology, to allow the use of tightly
spaced keys on a keypad with no loss of selectability by the user.
There can be up to three AKS groups, implemented so that only one key in the group may be reported as being
touched at any one time. Once a key in a particular AKS group is in detect no other key in that group can go into
detect. Only when the key in detect goes out of detection can another key go into detect state.
The keys which are members of the AKS groups can be set (see Section 5.9 on page 18). Keys outside the group
may be in detect simultaneously.
2.7 CHANGE Line (Comms Mode Only)
The CHANGE line is active low and signals when there is a change of state in the Detection or Input key status
bytes. It is cleared (allowed to float high) when the host reads the status bytes.
If the status bytes change back to their original state before the host has read the status bytes (for example, a touch
followed by a release), the CHANGE line will be held low. In this case, a read to any memory location will clear the
CHANGE line.
The CHANGE line is open-drain and should be connected via a 47 k resistor to Vdd. It is necessary for minimum
power operation as it ensures that the QT1070 can sleep for as long as possible. Communications wake up the
QT1070 from sleep causing a higher power consumption if the part is randomly polled.
Note: The CHANGE line is pulled low 100 ms after power-up or reset.
2.8 Types of Reset
2.8.1 External Reset
An external reset logic line can be used if desired, fed into the RESET pin. However, under most conditions it is
acceptable to tie RESET to Vdd.
2.8.2 Soft Reset
The host can cause a device reset by writing a nonzero value to the RESET byte. This soft reset triggers the internal
watchdog timer on a 125 ms interval. After 125 ms the device resets and wakes again.
The device NACKs any attempts to communicate with it during the first 30 ms of its initialization period.
2.9 Calibration
Writing a non-zero value to the calibration byte can force a recalibration at any time. This can be useful to clear out a
stuck key condition after a prolonged period of uninterrupted detection.
Note: A calibrate command clears all key status bits and the overflow bit (until it is checked on the next cycle).AT42QT1070 [DATASHEET] 10
9596C–AT42–05/2013
2.10 Guard Channel
A guard channel to help prevent false detection is available in both modes. This is fixed on key 0 for standalone
mode and programmable for comms mode.
Guard channel keys should be more sensitive than the other keys (physically bigger). Because the guard channel
key is physically bigger it becomes more susceptible to noise so it has a higher Averaging Factor (see Section 5.9 on
page 18) and a lower Threshold (see Section 5.8 on page 18) than the other keys. In standalone mode it has an
Averaging Factor of 16 and a Threshold of 10 counts.
A channel set as the guard channel (there can only be one) is prioritised when the filtering of keys going into detect
is taking place. So if a normal key is filtering into touch (touch present but DI has not been reached) and the key set
as the guard key begins filtering in, then the normal key’s filter is reset and the guard key filters in first.
The guard channel is connected to a sensor pad which detects the presence of touch and overrides any output from
the other keys.
Figure 2-1. Guard Channel Example
2.11 Signal Processing
2.11.1 Detect Threshold
The device detects a touch when the signal has crossed a threshold level and remained there for a specified number
of counts (see Section 5.10 on page 19). This can be altered on a key-by-key basis using the key threshold I2C
commands.
In standalone mode the detect threshold is set to a fixed value of 10 counts of change with respect to the internal
reference level for the guard channel and 20 counts for the other four keys. The reference level has the ability to
adjust itself slowly in accordance with the drift compensation mechanism.
The drift mechanism will drift toward touch at a rate of 160 ms × 18 = 2.88 seconds and away from touch at a rate of
160 ms × 6 = 0.96 seconds. The 160 ms is based on 20 × 8 ms cycles. If the cycle time exceeds 8 ms then the
overall times will be extended to match.
2.11.2 Detect Integrator
The device features a fast detection integrator counter (DI filter), which acts to filter out noise at the small expense of
a slower response time. The DI filter requires a programmable number of consecutive samples confirmed in
detection before the key is declared to be touched. The minimum number for the DI filter is 2. Settings of 0 and 1 for
the DI also default to 2.
The DI is also implemented when a touch is removed. This uses the Fast Out DI option. When bit 5 of Address 53 is
set the a key filters out with an integrator of 4.
Guard channelAT42QT1070 [DATASHEET] 11 9596C–AT42–05/2013
2.11.3 Cx Limitations
The recommended range for key capacitance Cx is 1 pF – 30 pF. Larger values of Cx will give reduced sensitivity.
2.11.4 Max On Duration
If an object or material obstructs the sense pad the signal may rise enough to create a detection, preventing further
operation. To prevent this, the sensor includes a timer which monitors detections. If a detection exceeds the timer
setting the sensor performs a key recalibration. This is known as the Max On duration feature and is set to
approximately 30 s in standalone mode.
In comms mode this feature can be changed by setting a value in the range 1 – 255
(160 ms – 40,800 ms) in steps of 160 ms. A setting of 0 disables the Max On Duration recalibration feature.
Note: If bit 4 of address 53 is clear then a recalibration of all keys occurs on Max On Duration, otherwise individual
key recalibration occurs.
2.11.5 Positive Recalibration
If a keys signal jumps in the negative direction (with respect to its reference) by more than the Positive Recalibration
setting (4 counts), then a recalibration of that key takes place.
2.11.6 Drift Hold Time
Drift Hold Time (DHT) is used to restrict drift on all keys while one or more keys are activated. DHT restricts the
drifting on all keys until approximately four seconds after all touches have been removed.
This feature is particularly useful in cases of high-density keypads where touching a key or hovering a finger over the
keypad would cause untouched keys to drift, and therefore create a sensitivity shift, and ultimately inhibit touch
detection.
2.11.7 Hysteresis
Hysteresis is fixed at 12.5% of the Detect Threshold. When a key enters a detect state once the DI count has been
reached, the NTHR value is changed by a small amount (12.5% of NTHR) in the direction away from touch. This is
done to affect hysteresis and so makes it less likely a key will dither in and out of detect. NTHR is restored once the
key drops out of detect.+AT42QT1070 [DATASHEET] 12
9596C–AT42–05/2013
3. Wiring and Parts
3.1 Rs Resistors
Series resistors Rs (Rs0 – Rs6 for comms mode and Rs0 – Rs4 for standalone mode) are in line with the electrode
connections and should be used to limit electrostatic discharge (ESD) currents and to suppress radio frequency
interference (RFI). Series resistors are recommended for noise reduction. They should be approximately 4.7 k to
20 k each.
3.2 LED Traces and Other Switching Signals
Digital switching signals near the sense lines induce transients into the acquired signals, deteriorating the signal-tonoise
(SNR) performance of the device. Such signals should be routed away from the sensing traces and electrodes,
or the design should be such that these lines are not switched during the course of signal acquisition (bursts).
LED terminals which are multiplexed or switched into a floating state, and which are within, or physically very near, a
key (even if on another nearby PCB) should be bypassed to either Vss or Vdd with at least a 10 nF capacitor. This is
to suppress capacitive coupling effects which can induce false signal shifts. The bypass capacitor does not need to
be next to the LED, in fact it can be quite distant. The bypass capacitor is noncritical and can be of any type.
LED terminals which are constantly connected to Vss or Vdd do not need further bypassing.
3.3 PCB Cleanliness
Modern no-clean flux is generally compatible with capacitive sensing circuits.
If a PCB is reworked in any way, clean it thoroughly to remove all traces of the flux residue around the capacitive
sensor components. Dry it thoroughly before any further testing is conducted.
3.4 Power Supply
See Section 6.2 on page 22 for the power supply range. If the power supply fluctuates slowly with temperature, the
device tracks and compensates for these changes automatically with only minor changes in sensitivity. If the supply
voltage drifts or shifts quickly, the drift compensation mechanism is not able to keep up, causing sensitivity
anomalies or false detections.
The usual power supply considerations with QT parts apply to the device. The power should be clean and come from
a separate regulator if possible. However, this device is designed to minimize the effects of unstable power, and
except in extreme conditions should not require a separate Low Dropout (LDO) regulator.
It is assumed that a larger bypass capacitor (such as1 µF) is somewhere else in the power circuit; for example, near
the regulator.
CAUTION: If a PCB is reworked in any way, it is highly likely that the behavior of the
no-clean flux will change. This can mean that the flux changes from an inert material
to one that can absorb moisture and dramatically affect capacitive measurements
due to additional leakage currents. If so, the circuit can become erratic and exhibit
poor environmental stability.
CAUTION: A regulator IC shared with other logic can result in erratic operation and is
not advised.
A single ceramic 0.1 µF bypass capacitor, with short traces, should be placed very
close to the power pins of the IC. Failure to do so can result in device oscillation, high
current consumption and erratic operation.AT42QT1070 [DATASHEET] 13 9596C–AT42–05/2013
4. I2
C Communications (Comms Mode Only)
4.1 I2
C Protocol
4.1.1 Protocol
The I2C protocol is based around access to an address table (see Table 5-1 on page 15) and supports multibyte
reads and writes. The maximum clock rate is 400 kHz.
See Section A. on page 29 for an overview of I2
C bus operation.
4.1.2 Signals
The I2
C interface requires two signals to operate:
SDA - Serial Data
SCL - Serial Clock
A third line, CHANGE, is used to signal when the device has seen a change in the status byte:
CHANGE: Open-drain, active low when any capacitive key has changed state since the last I2
C read. After reading
the two status bytes, this pin floats (high) again if it is pulled up with an external resistor. If the status bytes change
back to their original state before the host has read the status bytes (for example, a touch followed by a release), the
CHANGE line is held low. In this case, a read to any memory location clears the CHANGE line.
4.2 I2
C Address
There is one preset I2
C address of 0x1B. This is not changeable.
4.3 Data Read/Write
4.3.1 Writing Data to the Device
The sequence of events required to write data to the device is shown next.
1. The host initiates the transfer by sending the START condition
2. The host follows this by sending the slave address of the device together with the WRITE bit.
3. The device sends an ACK.
Table 4-1. Description of Write Data Bits
Key Description
S START condition
SLA+W Slave address plus write bit
A Acknowledge bit
MemAddress Target memory address within device
Data Data to be written
P Stop condition
S SLA+W A A MemAddress Data A P
Host to Device Device Tx to HostAT42QT1070 [DATASHEET] 14
9596C–AT42–05/2013
4. The host then sends the memory address within the device it wishes to write to.
5. The device sends an ACK if the write address is in the range 0x00 – 0x7F, otherwise it sends a NACK.
6. The host transmits one or more data bytes; each is acknowledged by the device (unless trying to write to an
invalid address).
7. If the host sends more than one data byte, they are written to consecutive memory addresses.
8. The device automatically increments the target memory address after writing each data byte.
9. After writing the last data byte, the host should send the STOP condition.
Note: the host should not try to write to addresses outside the range 0x20 to 0x39 because this is the limit of the
device internal memory address.
4.3.2 Reading Data From the Device
The sequence of events required to read data from the device is shown next.
1. The host initiates the transfer by sending the START condition
2. The host follows this by sending the slave address of the device together with the WRITE bit.
3. The device sends an ACK.
4. The host then sends the memory address within the device it wishes to read from.
5. The device sends an ACK if the address to be read from is less than 0x80 otherwise it sends a NACK).
6. The host must then send a STOP and a START condition followed by the slave address again but this time
accompanied by the READ bit.
Note: Alternatively, instead of step 6 a repeated START can be sent so the host does not need to
relinquish control of the bus.
7. The device returns an ACK, followed by a data byte.
8. The host must return either an ACK or NACK.
1. If the host returns an ACK, the device subsequently transmits the data byte from the next address. Each
time a data byte is transmitted, the device automatically increments the internal address. The device
continues to return data bytes until the host responds with a NACK.
2. If the host returns a NACK, it should then terminate the transfer by issuing the STOP condition.
9. The device resets the internal address to the location indicated by the memory address sent to it previously.
Therefore, there is no need to send the memory address again when reading from the same location.
Note: Reading the 16-bit reference and signal values is not an automatic operation; reading the first byte of a 16-
bit value does not lock the other byte. As a result glitches in the reported value may be seen as values
increase from 255 to 256, or decrease from 256 to 255.
4.4 SDA, SCL
The I2
C bus transmits data and clock with SDA and SCL respectively. They are open-drain; that is I2
C master and
slave devices can only drive these lines low or leave them open. The termination resistors pull the line up to Vdd if no
I
2
C device is pulling it down.
The termination resistors commonly range from 1 k to 10 k and should be chosen so that the rise times on SDA
and SCL meet the I2
C specifications (1 µs maximum).
Standalone mode: if I2
C communications are not required, then standalone mode can be enabled by connecting the
MODE pin to Vdd. See Section 2.4 on page 8 for more information.
S SLA+W A A MemAddress S SLA+R A
A P
Host to Device Device Tx to Host
P
Data 1 Data 2 A Data n AAT42QT1070 [DATASHEET] 15 9596C–AT42–05/2013
5. Setups
5.1 Introduction
The device calibrates and processes signals using a number of algorithms specifically designed to provide for high
survivability in the face of adverse environmental challenges. User-defined Setups are employed to alter these
algorithms to suit each application. These Setups are loaded into the device over the I2C serial interfaces. In
standalone mode these settings are fixed to predetermined values.
Table 5-1. Internal Register Address Allocation
Address Use Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 R/W
0 Chip ID Major ID (= 2) Minor ID (= E) R
1 Firmware Version Firmware version number R
2 Detection status CALIBRATE OVERFLOW – – – – – TOUCH R
3 Key status Reserved Key 6 Key 5 Key 4 Key 3 Key 2 Key 1 Key 0 R
4 – 5 Key signal 0 Key signal 0 (MSByte) – Key signal 0 (LSByte) R
6 – 7 Key signal 1 Key signal 1 (MSByte) – Key signal 1 (LSByte) R
8 – 9 Key signal 2 Key signal 2 (MSByte) – Key signal 2 (LSByte) R
10 – 11 Key signal 3 Key signal 3 (MSByte) – Key signal 3 (LSByte) R
12 – 13 Key signal 4 Key signal 4 (MSByte) – Key signal 4 (LSByte) R
14 – 15 Key signal 5 Key signal 5 (MSByte) – Key signal 5 (LSByte) R
16 – 17 Key signal 6 Key signal 6 (MSByte) – Key signal 6 (LSByte) R
18 – 19 Reference data 0 Reference data 0 (MSByte) – Reference data 0 (LSByte) R
20 – 21 Reference data 1 Reference data 1 (MSByte) – Reference data 1 (LSByte) R
22 – 23 Reference data 2 Reference data 2 (MSByte) – Reference data 2 (LSByte) R
24 – 25 Reference data 3 Reference data 3 (MSByte) – Reference data 3 (LSByte) R
26 – 27 Reference data 4 Reference data 4 (MSByte) – Reference data 4 (LSByte) R
28 – 29 Reference data 5 Reference data 5 (MSByte) – Reference data 5 (LSByte) R
30 – 31 Reference data 6 Reference data 6 (MSByte) – Reference data 6 (LSByte) R
32 NTHR key 0 Negative Threshold level for key 0 R/W
33 NTHR key 1 Negative Threshold level for key 1 R/W
34 NTHR key 2 Negative Threshold level for key 2 R/W
35 NTHR key 3 Negative Threshold level for key 3 R/W
36 NTHR key 4 Negative Threshold level for key 4 R/W
37 NTHR key 5 Negative Threshold level for key 5 R/W
38 NTHR key 6 Negative Threshold level for key 6 R/W
39 AVE/AKS key 0 Adjacent key suppression level for key 0 R/W
40 AVE/AKS key 1 Adjacent key suppression level for key 1 R/WAT42QT1070 [DATASHEET] 16
9596C–AT42–05/2013
5.2 Address 0: Chip ID
MAJOR ID: Reads back as 2
MINOR ID: Reads back as E
5.3 Address 1: Firmware Version
FIRMWARE VERSION: this shows the 8-bit firmware version 1.5 (0x15).
41 AVE/AKS key 2 Adjacent key suppression level for key 2 R/W
42 AVE/AKS key 3 Adjacent key suppression level for key 3 R/W
43 AVE/AKS key 4 Adjacent key suppression level for key 4 R/W
44 AVE/AKS key 5 Adjacent key suppression level for key 5 R/W
45 AVE/AKS key 6 Adjacent key suppression level for key 6 R/W
46 DI key 0 Detection integrator counter for key 0 R/W
47 DI key 1 Detection integrator counter for key 1 R/W
48 DI key 2 Detection integrator counter for key 2 R/W
49 DI key 3 Detection integrator counter for key 3 R/W
50 DI key 4 Detection integrator counter for key 4 R/W
51 DI key 5 Detection integrator counter for key 5 R/W
52 DI key 6 Detection integrator counter for key 6 R/W
53 FO/MO/Guard No FastOutDI/ Max Cal/Guard Channel R/W
54 LP Low Power (LP) Mode R/W
55 Max On Duration Maximum On Duration R/W
56 Calibrate Calibrate R/W
57 RESET RESET R/W
Table 5-1. Internal Register Address Allocation (Continued)
Address Use Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 R/W
Table 5-2. Chip ID
Address b7 b6 b5 b4 b3 b2 b1 b0
0 MAJOR ID MINOR ID
Table 5-3. Firmware Version
Address b7 b6 b5 b4 b3 b2 b1 b0
1 FIRMWARE VERSION AT42QT1070 [DATASHEET] 17 9596C–AT42–05/2013
5.4 Address 2: Detection Status
CALIBRATE: This bit is set during a calibration sequence.
OVERFLOW: This bit is set if the time to acquire all key signals exceeds 8 ms.
TOUCH: This bit is set if any keys are in detect.
5.5 Address 3: Key Status
KEY0 – 6: bits 0 to 6 indicate which keys are in detection, if any. Touched keys report as 1, untouched or disabled
keys report as 0.
5.6 Address 4 – 17: Key Signal
KEY SIGNAL: addresses 4 – 17 allow key signals to be read for each key, starting with key 0. There are two bytes of
data for each key. These are the key’s 16-bit key signals which are accessed as two 8-bit bytes, stored MSByte first.
These addresses are read-only.
Table 5-4. Detection Status
Address b7 b6 b5 b4 b3 b2 b1 b0
2 CALIBRATE OVERFLO
W – – – – – TOUCH
Table 5-5. Key Status
Address b7 b6 b5 b4 b3 b2 b1 b0
3 Reserved KEY6 KEY5 KEY4 KEY3 KEY2 KEY1 KEY0
Table 5-6. Key Signal
Address b7 b6 b5 b4 b3 b2 b1 b0
4 MSByte OF KEY SIGNAL FOR KEY 0
5 LSByte OF KEY SIGNAL FOR KEY 0
6 – 17 MSByte/LSByte OF KEY SIGNAL FOR KEYS 1 – 6AT42QT1070 [DATASHEET] 18
9596C–AT42–05/2013
5.7 Address 18 – 31: Reference Data
REFERENCE DATA: addresses 18 – 31 allow reference data to be read for each key, starting with key 0. There are
two bytes of data for each key. These are the key’s 16-bit reference data which is accessed as two 8-bit bytes, stored
MSByte first. These addresses are read-only.
5.8 Address 32 – 38: Negative Threshold (NTHR)
NTHR Keys 0 – 6: these 8-bit values set the threshold value for each key to register a detection.
Default: 20 counts
Note: Do not use a setting of 0 as this causes a key to go into detection when its signal is equal to its reference.
5.9 Address 39 – 45: Averaging Factor/Adjacent Key Suppression (AVE/AKS)
AVE 0 – 5: The Averaging Factor (AVE) is the number of pulses which are added together and averaged to get the
final signal value for that channel.
For example, if AVE = 8 then 8 ADC samples are taken and added together. The result is divided by the original
number of pulses (8). If sixteen pulses are used then the result is divided by sixteen.
This provides a better signal-to-noise ratio but requires longer acquire times. Values for AVE are restricted internally
to 1, 2, 4, 8, 16 or 32.
Default: 8 (In standalone mode key 0 is 16)
AKS 0 – 1: these bits control which keys are included in an AKS group. There can be up to three groups, each
containing any number of keys (up to the maximum allowed for the mode).
Each key can have a value between 0 and 3, which assigns it to an AKS group of that number. A key may only go
into detect when it has the largest signal change of any key in its group. A value of 0 means the key is not in any AKS
group.
Default: 0x01
Table 5-7. Reference Data
Address b7 b6 b5 b4 b3 b2 b1 b0
18 MSByte OF REFERENCE DATA FOR KEY 0
19 LSByte OF REFERENCE DATA FOR KEY 0
20 – 31 MSByte/LSByte OF REFERENCE DATA FOR KEYS 1 – 6
Table 5-8. NTHR
Address b7 b6 b5 b4 b3 b2 b1 b0
32 – 38 NEGATIVE THRESHOLD FOR KEYS 0 – 6
Table 5-9. AVE/AKS
Address b7 b6 b5 b4 b3 b2 b1 b0
39 – 45 AVE5 AVE4 AVE3 AVE2 AVE1 AVE0 AKS1 AKS0AT42QT1070 [DATASHEET] 19 9596C–AT42–05/2013
5.10 Address 46 – 52: Detection Integrator (DI)
DETECTION INTEGRATOR: addresses 46 – 52 allow the DI level to be set for each key. This 8-bit value controls
the number of consecutive measurements that must be confirmed as having passed the key threshold before that
key is registered as being in detect. The minimum value for the DI filter is 2. Settings of 0 and 1 for the DI also default
to 2 because a minimum of two consecutive measurements must be confirmed.
Default: 4
5.11 Address 53: FastOutDI/Max Cal/Guard Channel
FO: Fast Out DI – when bit 5 is set then a key filters out with an integrator of 4. Could have a DI in of 100 but filter out
with DI of 4 (global setting for all keys).
MAX CAL: if this bit is clear then all keys recalibrate after a Max On Duration timeout, otherwise only the key with the
incorrect timing gets recalibrated.
GUARD CHANNEL: bits 0 – 3 are used to set a key as the guard channel (which gets priority filtering). Valid values
are 0 – 6, with any larger value disabling the guard key feature.
5.12 Address 54: Low Power (LP) Mode
Table 5-10. Detection Integrator
Address b7 b6 b5 b4 b3 b2 b1 b0
46 – 52 DETECTION INTEGRATOR
Table 5-11. Max Cal/Guard Channel
Address b7 b6 b5 b4 b3 b2 b1 b0
53 – FO MAX CAL GUARD CHANNEL
Table 5-12. LP Mode
Address b7 b6 b5 b4 b3 b2 b1 b0
54 LOW POWER MODEAT42QT1070 [DATASHEET] 20
9596C–AT42–05/2013
LP MODE: this 8-bit value determines the number of 8 ms intervals between key measurements. Longer intervals
between measurements yield a lower power consumption but at the expense of a slower response to touch.
Default: 2 (16 ms between key acquisitions)
5.13 Address 55: Max On Duration
MAX ON DURATION: this is a 8-bit value which determines how long any key can be in touch before it recalibrates
itself.
A value of 0 turns Max On Duration off.
Default: 180 (160 ms × 180 = 28.8s)
Setting Time
0 8 ms
1 8 ms
2 16 ms
3 24 ms
4 32 ms
254 2.032s
255 2.040s
Table 5-13. Max Time On
Address b7 b6 b5 b4 b3 b2 b1 b0
55 MAX ON DURATION
Setting Time
0 Off
1 160 ms
2 320 ms
3 480 ms
4 640 ms
255 40.8sAT42QT1070 [DATASHEET] 21 9596C–AT42–05/2013
5.14 Address 56: Calibrate
Writing any nonzero value into this address triggers the device to start a calibration cycle. The CALIBRATE flag in
the detection status register is set when the calibration begins and clears when the calibration has finished.
5.15 Address 57: RESET
Writing any nonzero value to this address triggers the device to reset.
Table 5-14. Calibrate
Address b7 b6 b5 b4 b3 b2 b1 b0
56 Writing a nonzero value forces a calibration
Table 5-15. RESET
Address b7 b6 b5 b4 b3 b2 b1 b0
57 Writing a nonzero value forces a resetAT42QT1070 [DATASHEET] 22
9596C–AT42–05/2013
6. Specifications
6.1 Absolute Maximum Specifications
6.2 Recommended Operating Conditions
6.3 DC Specifications
Vdd –0.5 to +6 V
Max continuous pin current, any control or drive pin ±10 mA
Short circuit duration to ground, any pin infinite
Short circuit duration to Vdd, any pin infinite
Voltage forced onto any pin –0.5 V to (Vdd + 0.5) V
CAUTION: Stresses beyond those listed under Absolute Maximum Specifications may cause permanent damage to
the device. This is a stress rating only and functional operation of the device at these or other conditions beyond
those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum
specification conditions for extended periods may affect device reliability.
Operating temperature –40o
C to +85o
C
Storage temperature –55o
C to +125o
C
Vdd +1.8 V to 5.5 V
Supply ripple+noise ±25 mV
Cx load capacitance per key 1 to 30 pF
Vdd = 3.3 V, Cs = 10 nF, load = 5 pF, 32 ms default sleep, Ta = recommended range, unless otherwise noted
Parameter Description Minimum Typical Maximum Units Notes
Vil Low input logic level – – 0.2 × Vdd V
Vih High input logic level 0.7 × Vdd – Vdd + 0.5 V
Vol Low output voltage – – 0.6 V
Voh High output voltage Vdd –
0.7V – – V
Iil Input leakage current – – ±1 µAAT42QT1070 [DATASHEET] 23 9596C–AT42–05/2013
6.4 Power Consumption Measurements
6.5 Timing Specifications
Cx = 5 pF, Rs = 4.7 k
LP Mode
Idd (µA) at Vdd =
5 V 3.3 V 1.8 V
0 (8 ms) 1744 906 442
1 (16 ms) 1375 615 305
2 (24 ms) 1263 525 261
4 (32 ms) 1168 486 234
5 (40 ms) 1119 445 221
6 (48 ms) 1089 434 211
Paramete
r Description Minimum
Typica
l Maximum Units Notes
TR Response time DI
setting × 8 ms – LP mode +
(DI setting × 8 ms) ms Under host control
FQT Sample frequency 162 180 198 kHz
Modulated
spread-spectrum
(chirp)
TD
Power-up delay to
operate/calibration
time
– <230 – ms Can be longer if burst
is very long.
FI2C I
2
C clock rate – – 400 kHz –
Fm Burst modulation,
percentage ±8 % –
RESET pulse width 5 – – µs –AT42QT1070 [DATASHEET] 24
9596C–AT42–05/2013
6.6 Mechanical Dimensions
6.7 AT42QT1070-SSU – 14-pin SOIC
42077B-MCU-10/2013
USER GUIDE
Atmel OLED1 Xplained Pro
Preface
Atmel® OLED1 Xplained Pro is an extension board to the Atmel Xplained
Pro evaluation platform. The board enables the user to experiment with user
interface applications with buttons, LEDs and a display.Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
2
Table of Contents
Preface .......................................................................................... 1
1. Introduction .............................................................................. 3
1.1. Features .............................................................................. 3
1.2. Kit overview ......................................................................... 3
2. Getting started ......................................................................... 4
2.1. 3 Steps to start exploring the Atmel Xplained Pro platform ............. 4
2.2. Connecting OLED1 Xplained Pro to the Xplained Pro MCU
board. ................................................................................. 4
2.3. Design documentation and related links ..................................... 4
3. Xplained Pro ............................................................................ 5
3.1. Hardware identification system ................................................. 5
3.2. Standard headers and connectors ............................................ 5
3.2.1. Xplained Pro Standard Extension Header ...................... 5
4. Hardware user guide .............................................................. 7
4.1. Headers and connectors ......................................................... 7
4.1.1. OLED1 Xplained Pro extension header ......................... 7
4.2. Peripherals ........................................................................... 7
4.2.1. LEDs ...................................................................... 7
4.2.2. Push buttons ............................................................ 7
4.2.3. OLED display ........................................................... 8
5. Hardware revision history and known issues .......................... 9
5.1. Identifying product ID and revision ............................................ 9
5.2. Revision 3 ........................................................................... 9
6. Document revision history ..................................................... 10
7. Evaluation board/kit important notice .................................... 11Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
3
1. Introduction
1.1 Features
● UG-2832HSWEG04 monochrome OLED display
● 128 x 32 Pixels
● Controlled by 4-wire SPI interface, up to 100MHz
● Three LEDs
● Three Mechanical push buttons
● Xplained Pro hardware identification system
1.2 Kit overview
OLED1 Xplained Pro is a basic extension board for the Xplained Pro platform with three LEDs, three push
buttons and an OLED display. The OLED display is controlled via a SPI interface up to 100MHz. OLED1
Xplained Pro connects to any Xplained Pro standard extension header on any Xplained Pro MCU board.
Figure 1-1. OLED1 Xplained Pro top overview.Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
4
2. Getting started
2.1 3 Steps to start exploring the Atmel Xplained Pro platform
1. Download and install Atmel Studio.
2. Launch Atmel Studio.
3. Connect OLED1 Xplained Pro to an Xplained Pro MCU board and connect a USB cable to DEBUG USB
port on the Xplained Pro MCU board.
2.2 Connecting OLED1 Xplained Pro to the Xplained Pro MCU board.
Atmel OLED1 Xplained Pro has been designed to be connected to the Xplained Pro header marked EXT3.
However it is compatible with all Xplained Pro EXT headers. Please refer to the pin-out of your Xplained Pro
evaluation kit to find out which Xplained Pro EXT headers that can be used.
Once the Xplained Pro MCU board is powered the green power LED will be lit and Atmel Studio will auto
detect which Xplained Pro MCU- and extension board(s) that is connected. You will be presented with
relevant information like datasheets and kit documentation. You also have the option to launch Atmel Software
Framework (ASF) example applications. The target device is programmed and debugged by the on-board
Embedded Debugger. No external programmer or debugger tool is needed.
2.3 Design documentation and related links
The following list contains links to the most relevant documents and software for OLED1 Xplained Pro.
1. Xplained Pro products 1
- Atmel Xplained Pro is a series of small-sized and easy-to-use evaluation kits
for 8- and 32-bit Atmel microcontrollers. It consists of a series of low cost MCU boards for evaluation and
demonstration of features and capabilities of different MCU families.
2. OLED1 Xplained Pro User Guide 2
- PDF version of this User Guide.
3. OLED1 Xplained Pro Design Documentation 3
- Package containing schematics, BOM, assembly
drawings, 3D plots, layer plots etc.
4. Atmel Studio 4
- Free Atmel IDE for development of C/C++ and assembler code for Atmel
microcontrollers.
1
http://www.atmel.com/XplainedPro
2
http://www.atmel.com/Images/Atmel-42077-OLED1-Xplained-Pro_User-Guide.pdf
3
http://www.atmel.com/Images/Atmel-42077-OLED1-Xplained-Pro_User-Guide.zip
4
http://www.atmel.com/atmelstudioAtmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
5
3. Xplained Pro
Xplained Pro is an evaluation platform that provides the full Atmel microcontroller experience. The platform
consists of a series of Microcontroller (MCU) boards and extension boards that are integrated with Atmel
Studio, have Atmel Software Framework (ASF) drivers and demo code, support data streaming and more.
Xplained Pro MCU boards support a wide range of Xplained Pro extension boards that are connected through
a set of standardized headers and connectors. Each extension board has an identification (ID) chip to uniquely
identify which boards are mounted on a Xplained Pro MCU board. This information is used to present relevant
user guides, application notes, datasheets and example code through Atmel Studio. Available Xplained Pro
MCU and extension boards can be purchased in the Atmel Web Store
1
.
3.1 Hardware identification system
All Xplained Pro compatible extension boards have an Atmel ATSHA204 CryptoAuthentication™ chip mounted.
This chip contains information that identifies the extension with its name and some extra data. When an
Xplained Pro extension board is connected to an Xplained Pro MCU board the information is read and sent
to Atmel Studio. The Atmel Kits extension, installed with Atmel Studio, will give relevant information, code
examples and links to relevant documents. Table 3-1, “Xplained Pro ID Chip Content” on page 5 shows the
data fields stored in the ID chip with example content.
Table 3-1. Xplained Pro ID Chip Content
Data Field Data Type Example Content
Manufacturer ASCII string Atmel’\0’
Product Name ASCII string Segment LCD1 Xplained Pro’\0’
Product Revision ASCII string 02’\0’
Product Serial Number ASCII string 1774020200000010’\0’
Minimum Voltage [mV] uint16_t 3000
Maximum Voltage [mV] uint16_t 3600
Maximum Current [mA] uint16_t 30
3.2 Standard headers and connectors
3.2.1 Xplained Pro Standard Extension Header
All Xplained Pro kits have one or more dual row, 20 pin, 100mil extension headers. Xplained Pro MCU boards
have male headers while Xplained Pro extensions have their female counterparts. Note that all pins are not
always connected. However, all the connected pins follow the defined pin-out described in Table 3-2, “Xplained
Pro Extension Header” on page 5. The extension headers can be used to connect a wide variety of
Xplained Pro extensions to Xplained Pro MCU boards and to access the pins of the target MCU on Xplained
Pro MCU board directly.
Table 3-2. Xplained Pro Extension Header
Pin number Name Description
1 ID Communication line to the ID chip on extension board.
2 GND Ground.
3 ADC(+) Analog to digital converter , alternatively positive part of
differential ADC.
4 ADC(-) Analog to digital converter , alternatively negative part of
differential ADC.
5 GPIO1 General purpose I/O.
6 GPIO2 General purpose I/O.
7 PWM(+) Pulse width modulation , alternatively positive part of
differential PWM.
8 PWM(-) Pulse width modulation , alternatively positive part of
differential PWM.
1
http://store.atmel.com/Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
6
Pin number Name Description
9 IRQ/GPIO Interrupt request line and/or general purpose I/O.
10 SPI_SS_B/GPIO Slave select for SPI and/or general purpose I/O.
11 TWI_SDA Data line for two wire interface. Always implemented, bus
type.
12 TWI_SCL Clock line for two wire interface. Always implemented, bus
type.
13 USART_RX Receiver line of Universal Synchronous and Asynchronous
serial Receiver and Transmitter.
14 USART_TX Transmitter line of Universal Synchronous and
Asynchronous serial Receiver and Transmitter.
15 SPI_SS_A Slave select for SPI. Should be unique if possible.
16 SPI_MOSI Master out slave in line of Serial peripheral interface. Always
implemented, bus type.
17 SPI_MISO Master in slave out line of Serial peripheral interface. Always
implemented, bus type.
18 SPI_SCK Clock for Serial peripheral interface. Always implemented,
bus type.
19 GND Ground.
20 VCC Power for extension board.Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
7
4. Hardware user guide
4.1 Headers and connectors
4.1.1 OLED1 Xplained Pro extension header
OLED1 Xplained Pro implements one Xplained Pro Standard Extension Header on page 5 marked with
EXT in silkscreen. This header makes it possible to connect the board to any Xplained Pro MCU board.
The pin-out definition for the extension header can be seen in Table 4-1, “OLED1 Xplained Pro extension
header” on page 7.
Table 4-1. OLED1 Xplained Pro extension header
Pin Number Function Description
1 ID Communication line to ID chip
2 GND Ground
3 BUTTON2 Push button 2, active low
4 BUTTON3 Push button 3, active low
5 DATA_CMD_SEL Data / command select for OLED display. High = data, low =
command.
6 LED3 LED3, active low
7 LED1 LED1, active low
8 LED2 LED2, active low
9 BUTTON1 Push button 1, active low
10 DISPLAY_RESET Reset line for OLED display, active low
11 NC
12 NC
13 NC
14 NC
15 DISPLAY_SS OLED display slave select, active low
16 SPI MOSI MOSI signal SPI connected to OLED display
17 NC
18 SPI SCK Clock signal for SPI connected to OLED display
19 GND Ground
20 VCC Target supply voltage
4.2 Peripherals
4.2.1 LEDs
There are three yellow LEDs available on OLED1 Xplained Pro. The LEDs can be activated by driving the
connected I/O line low.
Table 4-2. LED connections
Pin on EXT connector Silk screen marking
7 LED1
8 LED2
6 LED3
4.2.2 Push buttons
There are three push buttons available on OLED1 Xplained Pro. When a button is pushed the corresponding
IO pin is connected to ground. There are no external pull-up resistors on OLED1 Xplained Pro, so internal pullup
resistors have to be enabled in the target microcontroller.Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
8
Note Remember to enable internal pull-up resistors in the target device to get a defined electrical level
on the IO lines connected to the buttons.
Table 4-3. Push button connections
Pin on EXT connector Silk screen marking
9 BUTTON1
3 BUTTON2
4 BUTTON3
4.2.3 OLED display
OLED1 Xplained Pro features a 128 x 32 pixel white monochrome OLED display, UG-2832HSWEG041
from
WiseChip Semiconductor Inc. The display has a SSD1306 display controller by Solomon Systech built in
and is controlled via a 4-wire SPI interface + reset with the signals described in Table 4-4, “OLED display
connections” on page 8. The datasheets for the display module or the display controller is not publicly
available and has to be acquired from the respective manufacturers.
Note Note that the OLED display does not have a SPI MISO signal. That means that data can only be
written to the display, not read.
Table 4-4. OLED display connections
Pin on EXT connector Signal Name Description
16 SPI_MOSI SPI master out, slave in signal.
Used to write data to the display
18 SPI_SCK SPI clock signal, generated by
the master.
5 DATA_CMD_SEL Data/command select.
Used to choose whether the
communication is data to the
display memory or a command to
the LCD controller.
15 DISPLAY_SS SPI slave select signal,
must be held low during SPI
communication.
10 DISPLAY_RESET Reset signal to the OLED
display, active low. Used during
initialization of the display.
1
http://www.wisechip.com.tw/english/Products_02-04.aspAtmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
9
5. Hardware revision history and known issues
5.1 Identifying product ID and revision
The revision and product identifier of Xplained Pro boards can be found in two ways, through Atmel Studio or
by looking at the sticker on the bottom side of the PCB.
By connecting a Xplained Pro MCU board to a computer with Atmel Studio running, an information window will
pop up. The first 6 digits of the serial number, which is listed under kit details, contain the product identifier and
revision. Information about connected Xplained Pro extension boards will also appear in the Atmel Kits window.
The same information can be found on the sticker on the bottom side of the PCB. Most kits will print the
identifier and revision in plain text as A09-nnnn\rr where nnnn is the identifier and rr is the revision. Boards with
limited space have a sticker with only a QR-code which contains a serial number string.
The serial number string has the following format:
"nnnnrrssssssssss"
n = product identifier
r = revision
s = serial number
The kit identifier for OLED1 Xplained Pro is 1769.
5.2 Revision 3
Revision 3 of OLED1 Xplained Pro is the initial released version.
OLED1 Xplained Pro boards with a serial number that ends with a number lower than 11148 may have a wrong
revision programmed into the Xplained Pro ID chip. This will only affect the information displayed by the Atmel
Kits extension in Atmel Studio. It will not affect the operation of the board.Atmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
10
6. Document revision history
Document
revision
Date Comment
42077B 09/2013 Added errata about revision 3 of the board.
42077A 25/02/2013 First releaseAtmel OLED1 Xplained Pro [USER GUIDE]
42077B-MCU-10/2013
11
7. Evaluation board/kit important notice
This evaluation board/kit is intended for use for FURTHER ENGINEERING, DEVELOPMENT,
DEMONSTRATION, OR EVALUATION PURPOSES ONLY. It is not a finished product and may not (yet)
comply with some or any technical or legal requirements that are applicable to finished products, including,
without limitation, directives regarding electromagnetic compatibility, recycling (WEEE), FCC, CE or UL
(except as may be otherwise noted on the board/kit). Atmel supplied this board/kit "AS IS," without any
warranties, with all faults, at the buyer's and further users' sole risk. The user assumes all responsibility
and liability for proper and safe handling of the goods. Further, the user indemnifies Atmel from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user's
responsibility to take any and all appropriate precautions with regard to electrostatic discharge and any other
technical or legal concerns.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER USER NOR
ATMEL SHALL BE LIABLE TO EACH OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES.
No license is granted under any patent right or other intellectual property right of Atmel covering or relating
to any machine, process, or combination in which such Atmel products or services might be or are used.Atmel Corporation 1600 Technology Drive, San Jose, CA 95110 USA T: (+1)(408) 441.0311 F: (+1)(408) 436.4200 | www.atmel.com
© 2013 Atmel Corporation. All rights reserved. / Rev.: 42077B-MCU-10/2013
Atmel®, Atmel logo and combinations thereof, Enabling Unlimited Possibilities®, and others are registered trademarks or trademarks of Atmel
Corporation or its subsidiaries. Other terms and product names may be trademarks of others.
Disclaimer: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted
by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN THE ATMEL TERMS AND CONDITIONS OF SALES LOCATED ON THE ATMEL WEBSITE,
ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY RELATING TO ITS PRODUCTS INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT SHALL ATMEL BE LIABLE FOR
ANY DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE, SPECIAL OR INCIDENTAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS AND PROFITS, BUSINESS
INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT, EVEN IF ATMEL HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES. Atmel makes no representations or warranties with respect to the accuracy or completeness of the contents of this document and reserves the right to make changes to
specifications and products descriptions at any time without notice. Atmel does not make any commitment to update the information contained herein. Unless specifically provided otherwise,
Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel products are not intended, authorized, or warranted for use as components in applications intended
to support or sustain life.
Atmel-8303H-AVR-ATtiny1634-Datasheet–02/2014
Features
• High Performance, Low Power AVR® 8-bit Microcontroller
• Advanced RISC Architecture
– 125 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
• High Endurance, Non-volatile Memory Segments
– 16K Bytes of In-System, Self-Programmable Flash Program Memory
• Endurance: 10,000 Write/Erase Cycles
– 256 Bytes of In-System Programmable EEPROM
• Endurance: 100,000 Write/Erase Cycles
– 1K Byte of Internal SRAM
– Data retention: 20 years at 85C / 100 years at 25C
– Programming Lock for Self-Programming Flash & EEPROM Data Security
• Peripheral Features
– Dedicated Hardware and QTouch® Library Support for Capacitive Touch Sensing
– One 8-bit and One 16-bit Timer/Counter with Two PWM Channels, Each
– 12-channel, 10-bit ADC
– Programmable Ultra Low Power Watchdog Timer
– On-chip Analog Comparator
– Two Full Duplex USARTs with Start Frame Detection
– Universal Serial Interface
– Slave I2
C Serial Interface
• Special Microcontroller Features
– debugWIRE On-chip Debug System
– In-System Programmable via SPI Port
– Internal and External Interrupt Sources
• Pin Change Interrupt on 18 Pins
– Low Power Idle, ADC Noise Reduction, Standby and Power-down Modes
– Enhanced Power-on Reset Circuit
– Programmable Brown-out Detection Circuit with Supply Voltage Sampling
– Calibrated 8MHz Oscillator with Temperature Calibration Option
– Calibrated 32kHz Ultra Low Power Oscillator
– On-chip Temperature Sensor
• I/O and Packages
– 18 Programmable I/O Lines
– 20-pad QFN/MLF, and 20-pin SOIC
• Operating Voltage:
– 1.8 – 5.5V
• Speed Grade:
– 0 – 2MHz @ 1.8 – 5.5V
– 0 – 8MHz @ 2.7 – 5.5V
– 0 – 12MHz @ 4.5 – 5.5V
• Temperature Range: -40C to +105C
• Low Power Consumption
– Active Mode: 0.2mA at 1.8V and 1MHz
– Idle Mode: 30µA at 1.8V and 1MHz
– Power-Down Mode (WDT Enabled): 1µA at 1.8V
– Power-Down Mode (WDT Disabled): 100nA at 1.8V
8-bit Atmel tinyAVR Microcontroller with
16K Bytes In-System Programmable Flash
ATtiny1634ATtiny1634 [DATASHEET] 2
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
1. Pin Configurations
Figure 1-1. Pinout of ATtiny1634
1
2
3
4
5
QFN/MLF
15
14
13
12
11
20
19
18
17
16
6
7
8
9
10
NOTE
Bottom pad should be
soldered to ground.
(PCINT1/AIN0) PA1
(PCINT0/AREF) PA0
GND
VCC
PC5 (XTAL1/CLKI/PCINT17)
PC0 (ADC9/OC0A/XCK0/PCINT12)
PC1 (ADC10/ICP1/SCL/USCK/XCK1/PCINT13)
PC2 (ADC11/CLKO/INT0/PCINT14)
PC3 (RESET/dW/PCINT15)
PC4 (XTAL2/PCINT16)
PA7 (PCINT7/RXD0/ADC4)
PB0 (PCINT8/TXD0/ADC5)
PB1 (ADC6/DI/SDA/RXD1/PCINT9)
PB2 (ADC7/DO/TXD1/PCINT10)
PB3 (ADC8/OC1A/PCINT11)
(PCINT6/OC1B/ADC3) PA6
(PCINT5/OC0B/ADC2) PA5
(PCINT4/T0/ADC1) PA4
(PCINT3/T1/SNS/ADC0) PA3
(PCINT2/AIN1) PA2
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
(PCINT8/TXD0/ADC5) PB0
(PCINT7/RXD0/ADC4) PA7
(PCINT6/OC1B/ADC3) PA6
(PCINT5/OC0B/ADC2) PA5
(PCINT4/T0/ADC1) PA4
(PCINT3/T1/SNS/ADC0) PA3
(PCINT2/AIN1) PA2
(PCINT1/AIN0) PA1
(PCINT0/AREF) PA0
GND
PB1 (ADC6/DI/SDA/RXD1/PCINT9)
PB2 (ADC7/DO/TXD1/PCINT10)
PB3 (ADC8/OC1A/PCINT11)
PC0 (ADC9/OC0A/XCK0/PCINT12)
PC1 (ADC10/ICP1/SCL/USCK/XCK1/PCINT13)
PC2 (ADC11/CLKO/INT0/PCINT14)
PC3 (RESET/dW/PCINT15)
PC4 (XTAL2/PCINT16)
PC5 (XTAL1/CLKI/PCINT17)
VCC
SOICATtiny1634 [DATASHEET] 3
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
1.1 Pin Descriptions
1.1.1 VCC
Supply voltage.
1.1.2 GND
Ground.
1.1.3 XTAL1
Input to the inverting amplifier of the oscillator and the internal clock circuit. This is an alternative pin configuration
of PC5.
1.1.4 XTAL2
Output from the inverting amplifier of the oscillator. Alternative pin configuration of PC4.
1.1.5 RESET
Reset input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if the clock
is not running and provided the reset pin has not been disabled. The minimum pulse length is given in Table 24-5
on page 231. Shorter pulses are not guaranteed to generate a reset.
The reset pin can also be used as a (weak) I/O pin.
1.1.6 Port A (PA7:PA0)
This is an 8-bit, bi-directional I/O port with internal pull-up resistors (selected for each bit). Output buffers have the
following drive characteristics:
• PA7, PA4:PA0: Symmetrical, with standard sink and source capability
• PA6, PA5: Asymmetrical, with high sink and standard source capability
As inputs, port pins that are externally pulled low will source current provided that pull-up resistors are activated.
Port pins are tri-stated when a reset condition becomes active, even if the clock is not running.
This port has alternate pin functions to serve special features of the device. See “Alternate Functions of Port A” on
page 62.
1.1.7 Port B (PB3:PB0)
This is a 4-bit, bi-directional I/O port with internal pull-up resistors (selected for each bit).Output buffers have the
following drive characteristics:
• PB3: Asymmetrical, with high sink and standard source capability
• PB2:PB0: Symmetrical, with standard sink and source capability
As inputs, port pins that are externally pulled low will source current provided that pull-up resistors are activated.
Port pins are tri-stated when a reset condition becomes active, even if the clock is not running.
This port has alternate pin functions to serve special features of the device. See “Alternate Functions of Port B” on
page 65.
1.1.8 Port C (PC5:PC0)
This is a 6-bit, bi-directional I/O port with internal pull-up resistors (selected for each bit). Output buffers have the
following drive characteristics:ATtiny1634 [DATASHEET] 4
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
• PC5:PC1: Symmetrical, with standard sink and source capability
• PC0: Asymmetrical, with high sink and standard source capability
As inputs, port pins that are externally pulled low will source current provided that pull-up resistors are activated.
Port pins are tri-stated when a reset condition becomes active, even if the clock is not running.
This port has alternate pin functions to serve special features of the device. See “Alternate Functions of Port C” on
page 67.
2. Overview
ATtiny1634 is a low-power CMOS 8-bit microcontrollers based on the AVR enhanced RISC architecture. By executing
powerful instructions in a single clock cycle, the ATtiny1634 achieves throughputs approaching 1 MIPS per
MHz allowing the system designer to optimize power consumption versus processing speed.
Figure 2-1. Block Diagram
DEBUG
INTERFACE
CALIBRATED ULP
OSCILLATOR
WATCHDOG
TIMER
CALIBRATED
OSCILLATOR
TIMING AND
CONTROL
VCC RESET GND
8-BIT DATA BUS
CPU CORE
PROGRAM
MEMORY
(FLASH)
DATA
MEMORY
(SRAM)
POWER
SUPERVISION:
POR
BOD
RESET
ISP
INTERFACE
PORT A PORT B PORT C
VOLTAGE
REFERENCE
MULTIPLEXER ANALOG
COMPARATOR
ADC
TEMPERATURE
SENSOR
TWO-WIRE
INTERFACE
USART0
TOUCH
SENSING
EEPROM
ON-CHIP
DEBUGGER
PA[7:0] PB[3:0] PC[5:0]
8-BIT
TIMER/COUNTER
16-BIT
TIMER/COUNTER
USI
USART1ATtiny1634 [DATASHEET] 5
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
The AVR core combines a rich instruction set with 32 general purpose working registers. All 32 registers are
directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in a single
instruction, executed in one clock cycle. The resulting architecture is compact and code efficient while achieving
throughputs up to ten times faster than conventional CISC microcontrollers.
ATtiny1634 provides the following features:
• 16K bytes of in-system programmable Flash
• 1K bytes of SRAM data memory
• 256 bytes of EEPROM data memory
• 18 general purpose I/O lines
• 32 general purpose working registers
• An 8-bit timer/counter with two PWM channels
• A16-bit timer/counter with two PWM channels
• Internal and external interrupts
• A 10-bit ADC with 5 internal and 12 external channels
• An ultra-low power, programmable watchdog timer with internal oscillator
• Two programmable USART’s with start frame detection
• A slave Two-Wire Interface (TWI)
• A Universal Serial Interface (USI) with start condition detector
• A calibrated 8MHz oscillator
• A calibrated 32kHz, ultra low power oscillator
• Four software selectable power saving modes.
The device includes the following modes for saving power:
• Idle mode: stops the CPU while allowing the timer/counter, ADC, analog comparator, SPI, TWI, and interrupt
system to continue functioning
• ADC Noise Reduction mode: minimizes switching noise during ADC conversions by stopping the CPU and all
I/O modules except the ADC
• Power-down mode: registers keep their contents and all chip functions are disabled until the next interrupt or
hardware reset
• Standby mode: the oscillator is running while the rest of the device is sleeping, allowing very fast start-up
combined with low power consumption.
The device is manufactured using Atmel’s high density non-volatile memory technology. The Flash program memory
can be re-programmed in-system through a serial interface, by a conventional non-volatile memory
programmer or by an on-chip boot code, running on the AVR core.
The ATtiny1634 AVR is supported by a full suite of program and system development tools including: C compilers,
macro assemblers, program debugger/simulators and evaluation kits.ATtiny1634 [DATASHEET] 6
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
3. General Information
3.1 Resources
A comprehensive set of drivers, application notes, data sheets and descriptions on development tools are available
for download at http://www.atmel.com/avr.
3.2 Code Examples
This documentation contains simple code examples that briefly show how to use various parts of the device. These
code examples assume that the part specific header file is included before compilation. Be aware that not all C
compiler vendors include bit definitions in the header files and interrupt handling in C is compiler dependent.
Please confirm with the C compiler documentation for more details.
For I/O Registers located in the extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”, and “SBI” instructions must
be replaced with instructions that allow access to extended I/O. Typically, this means “LDS” and “STS” combined
with “SBRS”, “SBRC”, “SBR”, and “CBR”. Note that not all AVR devices include an extended I/O map.
3.3 Capacitive Touch Sensing
Atmel QTouch Library provides a simple to use solution for touch sensitive interfaces on Atmel AVR microcontrollers.
The QTouch Library includes support for QTouch® and QMatrix® acquisition methods.
Touch sensing is easily added to any application by linking the QTouch Library and using the Application Programming
Interface (API) of the library to define the touch channels and sensors. The application then calls the API to
retrieve channel information and determine the state of the touch sensor.
The QTouch Library is free and can be downloaded from the Atmel website. For more information and details of
implementation, refer to the QTouch Library User Guide – also available from the Atmel website.
3.4 Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less than 1 PPM over 20
years at 85°C or 100 years at 25°C.
4. CPU Core
This section discusses the AVR core architecture in general. The main function of the CPU core is to ensure correct
program execution. The CPU must therefore be able to access memories, perform calculations, control
peripherals, and handle interrupts.ATtiny1634 [DATASHEET] 7
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
4.1 Architectural Overview
Figure 4-1. Block Diagram of the AVR Architecture
In order to maximize performance and parallelism, the AVR uses a Harvard architecture – with separate memories
and buses for program and data. Instructions in the Program memory are executed with a single level pipelining.
While one instruction is being executed, the next instruction is pre-fetched from the Program memory. This concept
enables instructions to be executed in every clock cycle. The Program memory is In-System Reprogrammable
Flash memory.
The fast-access Register File contains 32 x 8-bit general purpose working registers with a single clock cycle
access time. This allows single-cycle Arithmetic Logic Unit (ALU) operation. In a typical ALU operation, two operands
are output from the Register File, the operation is executed, and the result is stored back in the Register File
– in one clock cycle.
Six of the 32 registers can be used as three 16-bit indirect address register pointers for Data Space addressing –
enabling efficient address calculations. One of the these address pointers can also be used as an address pointer
for look up tables in Flash Program memory. These added function registers are the 16-bit X-, Y-, and Z-register,
described later in this section.
The ALU supports arithmetic and logic operations between registers or between a constant and a register. Single
register operations can also be executed in the ALU. After an arithmetic operation, the Status Register is updated
to reflect information about the result of the operation.
Program flow is provided by conditional and unconditional jump and call instructions, capable of directly addressing
the whole address space. Most AVR instructions have a single 16-bit word format but 32-bit wide instructions also
exist. The actual instruction set varies, as some devices only implement a part of the instruction set.
INTERRUPT
UNIT
STATUS AND
CONTROL
PROGRAM
MEMORY
(FLASH)
DATA
MEMORY
(SRAM)
PROGRAM
COUNTER
INSTRUCTION
REGISTER
INSTRUCTION
DECODER
CONTROL
LINES
GENERAL
PURPOSE
REGISTERS
X
Y
Z
ALU
DIRECT ADDRESSING
INDIRECT ADDRESSING
8-BIT DATA BUSATtiny1634 [DATASHEET] 8
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
During interrupts and subroutine calls, the return address Program Counter (PC) is stored on the Stack. The Stack
is effectively allocated in the general data SRAM, and consequently the Stack size is only limited by the total
SRAM size and the usage of the SRAM. All user programs must initialize the SP in the Reset routine (before subroutines
or interrupts are executed). The Stack Pointer (SP) is read/write accessible in the I/O space. The data
SRAM can easily be accessed through the five different addressing modes supported in the AVR architecture.
The memory spaces in the AVR architecture are all linear and regular memory maps.
A flexible interrupt module has its control registers in the I/O space with an additional Global Interrupt Enable bit in
the Status Register. All interrupts have a separate Interrupt Vector in the Interrupt Vector table. The interrupts have
priority in accordance with their Interrupt Vector position. The lower the Interrupt Vector address, the higher the
priority.
The I/O memory space contains 64 addresses for CPU peripheral functions as Control Registers, SPI, and other
I/O functions. The I/O memory can be accessed directly, or as the Data Space locations following those of the Register
File, 0x20 - 0x5F. In addition, the ATtiny1634 has Extended I/O Space from 0x60 - 0xFF in SRAM where only
the ST/STS/STD and LD/LDS/LDD instructions can be used.
4.2 ALU – Arithmetic Logic Unit
The high-performance AVR ALU operates in direct connection with all the 32 general purpose working registers.
Within a single clock cycle, arithmetic operations between general purpose registers or between a register and an
immediate are executed. The ALU operations are divided into three main categories – arithmetic, logical, and bitfunctions.
Some implementations of the architecture also provide a powerful multiplier supporting both
signed/unsigned multiplication and fractional format. See external document “AVR Instruction Set” and “Instruction
Set Summary” on page 278 section for more information.
4.3 Status Register
The Status Register contains information about the result of the most recently executed arithmetic instruction. This
information can be used for altering program flow in order to perform conditional operations. Note that the Status
Register is updated after all ALU operations. This will in many cases remove the need for using the dedicated compare
instructions, resulting in faster and more compact code. See external document “AVR Instruction Set” and
“Instruction Set Summary” on page 278 section for more information.
The Status Register is neither automatically stored when entering an interrupt routine, nor restored when returning
from an interrupt. This must be handled by software.
4.4 General Purpose Register File
The Register File is optimized for the AVR Enhanced RISC instruction set. In order to achieve the required performance
and flexibility, the following input/output schemes are supported by the Register File:
• One 8-bit output operand and one 8-bit result input
• Two 8-bit output operands and one 8-bit result input
• Two 8-bit output operands and one 16-bit result input
• One 16-bit output operand and one 16-bit result input
Figure 4-2 below shows the structure of the 32 general purpose working registers in the CPU.ATtiny1634 [DATASHEET] 9
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Figure 4-2. General Purpose Working Registers
Most of the instructions operating on the Register File have direct access to all registers, and most of them are single
cycle instructions.
As shown in Figure 4-2, each register is also assigned a Data memory address, mapping them directly into the first
32 locations of the user Data Space. Although not being physically implemented as SRAM locations, this memory
organization provides great flexibility in access of the registers, as the X-, Y- and Z-pointer registers can be set to
index any register in the file.
4.4.1 The X-register, Y-register, and Z-register
The registers R26..R31 have added functions to their general purpose usage. These registers are 16-bit address
pointers for indirect addressing of the data space. The three indirect address registers X, Y, and Z are defined as
described in Figure 4-3 below.
7 0 Addr. Special Function
R0 0x00
R1 0x01
R2 0x02
R3 0x03
… ...
R12 0x0C
R13 0x0D
R14 0x0E
R15 0x0F
R16 0x10
R17 0x11
… ...
R26 0x1A X-register Low Byte
R27 0x1B X-register High Byte
R28 0x1C Y-register Low Byte
R29 0x1D Y-register High Byte
R30 0x1E Z-register Low Byte
R31 0x1F Z-register High ByteATtiny1634 [DATASHEET] 10
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Figure 4-3. The X-, Y-, and Z-registers
In the different addressing modes these address registers have functions as fixed displacement, automatic increment,
and automatic decrement (see the instruction set reference for details).
4.5 Stack Pointer
The stack is mainly used for storing temporary data, local variables and return addresses after interrupts and subroutine
calls. The Stack Pointer registers (SPH and SPL) always point to the top of the stack. Note that the stack
grows from higher memory locations to lower memory locations. This means that the PUSH instructions decreases
and the POP instruction increases the stack pointer value.
The stack pointer points to the area of data memory where subroutine and interrupt stacks are located. This stack
space must be defined by the program before any subroutine calls are executed or interrupts are enabled.
The pointer is decremented by one when data is put on the stack with the PUSH instruction, and incremented by
one when data is fetched with the POP instruction. It is decremented by two when the return address is put on the
stack by a subroutine call or a jump to an interrupt service routine, and incremented by two when data is fetched by
a return from subroutine (the RET instruction) or a return from interrupt service routine (the RETI instruction).
The AVR stack pointer is typically implemented as two 8-bit registers in the I/O register file. The width of the stack
pointer and the number of bits implemented is device dependent. In some AVR devices all data memory can be
addressed using SPL, only. In this case, the SPH register is not implemented.
The stack pointer must be set to point above the I/O register areas, the minimum value being the lowest address of
SRAM. See Table 5-2 on page 16.
4.6 Instruction Execution Timing
This section describes the general access timing concepts for instruction execution. The AVR CPU is driven by the
CPU clock clkCPU, directly generated from the selected clock source for the chip. No internal clock division is used.
Figure 4-4 shows the parallel instruction fetches and instruction executions enabled by the Harvard architecture
and the fast access Register File concept. This is the basic pipelining concept to obtain up to 1 MIPS per MHz with
the corresponding unique results for functions per cost, functions per clocks, and functions per power-unit.
15 0
X-register 7 XH 0 7 XL 0
R27 R26
15 0
Y-register 7 YH 0 7 YL 0
R29 R28
15 0
Z-register 7 ZH 0 7 ZL 0
R31 R30ATtiny1634 [DATASHEET] 11
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Figure 4-4. The Parallel Instruction Fetches and Instruction Executions
Figure 4-5 shows the internal timing concept for the Register File. In a single clock cycle an ALU operation using
two register operands is executed, and the result is stored back to the destination register.
Figure 4-5. Single Cycle ALU Operation
4.7 Reset and Interrupt Handling
The AVR provides several different interrupt sources. These interrupts and the separate Reset Vector each have a
separate Program Vector in the Program memory space. All interrupts are assigned individual enable bits which
must be written logic one together with the Global Interrupt Enable bit in the Status Register in order to enable the
interrupt.
The lowest addresses in the Program memory space are by default defined as the Reset and Interrupt Vectors.
The complete list of vectors is shown in “Interrupts” on page 47. The list also determines the priority levels of the
different interrupts. The lower the address the higher is the priority level. RESET has the highest priority, and next
is INT0 – the External Interrupt Request 0.
When an interrupt occurs, the Global Interrupt Enable I-bit is cleared and all interrupts are disabled. The user software
can write logic one to the I-bit to enable nested interrupts. All enabled interrupts can then interrupt the current
interrupt routine. The I-bit is automatically set when a Return from Interrupt instruction – RETI – is executed.
There are basically two types of interrupts. The first type is triggered by an event that sets the Interrupt Flag. For
these interrupts, the Program Counter is vectored to the actual Interrupt Vector in order to execute the interrupt
handling routine, and hardware clears the corresponding Interrupt Flag. Interrupt Flags can also be cleared by writing
a logic one to the flag bit position(s) to be cleared. If an interrupt condition occurs while the corresponding
interrupt enable bit is cleared, the Interrupt Flag will be set and remembered until the interrupt is enabled, or the
flag is cleared by software. Similarly, if one or more interrupt conditions occur while the Global Interrupt Enable bit
is cleared, the corresponding Interrupt Flag(s) will be set and remembered until the Global Interrupt Enable bit is
set, and will then be executed by order of priority.
clk
1st Instruction Fetch
1st Instruction Execute
2nd Instruction Fetch
2nd Instruction Execute
3rd Instruction Fetch
3rd Instruction Execute
4th Instruction Fetch
T1 T2 T3 T4
CPU
Total Execution Time
Register Operands Fetch
ALU Operation Execute
Result Write Back
T1 T2 T3 T4
clkCPUATtiny1634 [DATASHEET] 12
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
The second type of interrupts will trigger as long as the interrupt condition is present. These interrupts do not necessarily
have Interrupt Flags. If the interrupt condition disappears before the interrupt is enabled, the interrupt will
not be triggered.
When the AVR exits from an interrupt, it will always return to the main program and execute one more instruction
before any pending interrupt is served.
Note that the Status Register is not automatically stored when entering an interrupt routine, nor restored when
returning from an interrupt routine. This must be handled by software.
When using the CLI instruction to disable interrupts, the interrupts will be immediately disabled. No interrupt will be
executed after the CLI instruction, even if it occurs simultaneously with the CLI instruction. The following example
shows how this can be used to avoid interrupts during the timed EEPROM write sequence.
Note: See “Code Examples” on page 6.
When using the SEI instruction to enable interrupts, the instruction following SEI will be executed before any pending
interrupts, as shown in the following example.
Note: See “Code Examples” on page 6.
4.7.1 Interrupt Response Time
The interrupt execution response for all the enabled AVR interrupts is four clock cycles minimum. After four clock
cycles the Program Vector address for the actual interrupt handling routine is executed. During this four clock cycle
Assembly Code Example
in r16, SREG ; store SREG value
cli ; disable interrupts during timed sequence
sbi EECR, EEMPE ; start EEPROM write
sbi EECR, EEPE
out SREG, r16 ; restore SREG value (I-bit)
C Code Example
char cSREG;
cSREG = SREG; /* store SREG value */
/* disable interrupts during timed sequence */
_CLI();
EECR |= (1< 1MHz 12 – 22 pF
XTAL2
XTAL1
GND
C2
C1ATtiny1634 [DATASHEET] 29
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
The ripple counter that implements the prescaler runs at the frequency of the undivided clock, which may be faster
than the CPU's clock frequency. Hence, it is not possible to determine the state of the prescaler - even if it were
readable, and the exact time it takes to switch from one clock division to another cannot be exactly predicted.
From the time the CLKPS values are written, it takes between T1 + T2 and T1 + 2*T2 before the new clock frequency
is active. In this interval, 2 active clock edges are produced. Here, T1 is the previous clock period, and T2
is the period corresponding to the new prescaler setting.
6.4 Clock Output Buffer
The device can output the system clock on the CLKO pin. To enable the output, the CKOUT_IO bit has to be programmed.
The CKOUT fuse determines the initial value of the CKOUT_IO bit that is loaded to the CLKSR register
when the device is powered up or has been reset. The clock output can be switched at run-time by setting the
CKOUT_IO bit in CLKSR as described in chapter “CLKSR – Clock Setting Register” on page 29.
This mode is suitable when the chip clock is used to drive other circuits on the system. Note that the clock will not
be output during reset and that the normal operation of the I/O pin will be overridden when the fuse is programmed.
Any clock source, including the internal oscillators, can be selected when the clock is output on CLKO. If the System
Clock Prescaler is used, it is the divided system clock that is output.
6.5 Register Description
6.5.1 CLKSR – Clock Setting Register
• Bit 7 – OSCRDY: Oscillator Ready
This bit is set when oscillator time-out is complete. When OSCRDY is set the oscillator is stable and the clock
source can be changed safely.
• Bit 6 – CSTR: Clock Select Trigger
This bit triggers the clock selection. It can be used to enable the oscillator in advance and select the clock source,
before the oscillator is stable.
If CSTR is set at the same time as the CKSEL bits are written, the contents are directly copied to the CKSEL register
and the system clock is immediately switched.
If CKSEL bits are written without setting CSTR, the oscillator selected by the CKSEL bits is enabled, but the system
clock is not switched yet.
• Bit 5 – CKOUT_IO: Clock Output
This bit enables the clock output buffer. The CKOUT fuse determines the initial value of the CKOUT_IO bit that is
loaded to the CLKSR register when the device is powered up or has been reset
• Bit 4 – SUT: Start-Up Time
The SUT and CKSEL bits define the start-up time of the device, as shown in Table 6-2, below. The initial value of
the SUT bit is determined by the SUT fuse. The SUT fuse is loaded to the SUT bit when the device is powered up
or has been reset.
Bit 7 6 5 4 3 2 1 0
0x32 (0x52) OSCRDY CSTR CKOUT_IO SUT CKSEL3 CKSEL2 CKSEL1 CKSEL0 CLKSR
Read/Write R W R R R/W R/W R/W R/W
Initial Value 0 0 0 See Bit DescriptionATtiny1634 [DATASHEET] 30
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Note: 1. Device start-up time from power-down sleep mode.
2. When BOD has been disabled by software, the wake-up time from sleep mode will be approximately 60µs to
ensure the BOD is working correctly before MCU continues executing code.
3. Device start-up time after reset.
4. The device is shipped with this option selected.
5. This option is not suitable for use with crystals.
6. This option should not be used when operating close to the maximum frequency of the device, and only if frequency
stability at start-up is not important for the application.
7. This option is intended for use with ceramic resonators and will ensure frequency stability at start-up. It can also be
used with crystals when not operating close to the maximum frequency of the device, and if frequency stability at
start-up is not important for the application.
• Bits 3:0 – CKSEL[3:0]: Clock Select Bits
These bits select the clock source of the system clock and can be written at run-time. The clock system ensures
glitch free switching of the clock source. CKSEL fuses determine the initial value of the CKSEL bits when the
device is powered up or reset.
The clock alternatives are shown in Table 6-3 below.
Table 6-2. Device Start-up Times
SUT CKSEL Clock From Power-Down (1)(2) From Reset (3)
0 (4)
0000 External 6 CK 22 CK + 16ms
0010 (4) Internal 8MHz 6 CK 20 CK + 16ms
0100 Internal 32kHz 6 CK 22 CK + 16ms
0001
0011
0101 ... 0111
Reserved
1XX0 Ceramic resonator (5) 258 CK (6) 274 CK + 16ms
1XX1 Crystal oscillator 16K CK 16K CK + 16 ms
1
0000 ... 0111
1XX1 Reserved
1XX0 Ceramic resonator 1K CK (7) 1K CK +16ms
Table 6-3. Device Clocking Options
CKSEL[3:0] (1) Frequency Device Clocking Option
0000 Any External Clock (see page 26)
0010 8MHz Calibrated Internal 8MHz Oscillator (see page 27) (2)
0100 32kHz Internal 32kHz Ultra Low Power (ULP) Oscillator (see page 27)
00X1
0101 ... 0111 — Reserved
100X 0.4...0.9MHz
Crystal Oscillator / Ceramic Resonator (see page 27)
101X 0.9...3MHz
110X 3...8MHz
111X > 8MHzATtiny1634 [DATASHEET] 31
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Note: 1. For all fuses “1” means unprogrammed and “0” means programmed.
2. This is the default setting. The device is shipped with this fuse combination.
To avoid unintentional switching of clock source, a protected change sequence must be followed to change the
CKSEL bits, as follows:
1. Write the signature for change enable of protected I/O register to register CCP.
2. Within four instruction cycles, write the CKSEL bits with the desired value.
6.5.2 CLKPR – Clock Prescale Register
• Bits 7:4 – Res: Reserved Bits
These bits are reserved and will always read zero.
• Bits 3:0 – CLKPS[3:0]: Clock Prescaler Select Bits 3 - 0
These bits define the division factor between the selected clock source and the internal system clock. These bits
can be written run-time to vary the clock frequency to suit the application requirements. As the divider divides the
master clock input to the MCU, the speed of all synchronous peripherals is reduced when a division factor is used.
The division factors are given in Table 6-4 on page 31.
To avoid unintentional changes of clock frequency, a protected change sequence must be followed to change the
CLKPS bits:
1. Write the signature for change enable of protected I/O register to register CCP.
2. Within four instruction cycles, write the desired value to CLKPS bits.
Interrupts must be disabled when changing prescaler setting to make sure the write procedure is not interrupted.
Bit 7 6 5 4 3 2 1 0
0x33 (0x53) – – – – CLKPS3 CLKPS2 CLKPS1 CLKPS0 CLKPR
Read/Write R R R R R/W R/W R/W R/W
Initial Value 0 0 0 0 See Bit Description
Table 6-4. Clock Prescaler Select
CLKPS3 CLKPS2 CLKPS1 CLKPS0 Clock Division Factor
0 0 0 0 1 (1)
0001 2
0010 4
0 0 1 1 8 (2)
0 1 0 0 16
0 1 0 1 32
0 1 1 0 64
0 1 1 1 128
1 0 0 0 256ATtiny1634 [DATASHEET] 32
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Note: 1. This is the initial value when CKDIV8 fuse has been unprogrammed.
2. This is the initial value when CKDIV8 fuse has been programmed. The device is shipped with the CKDIV8 Fuse
programmed.
The initial value of clock prescaler bits is determined by the CKDIV8 fuse (see Table 22-5 on page 210). When
CKDIV8 is unprogrammed, the system clock prescaler is set to one and, when programmed, to eight. Any value
can be written to the CLKPS bits regardless of the CKDIV8 fuse bit setting.
When CKDIV8 is programmed the initial value of CLKPS bits give a clock division factor of eight at start up. This is
useful when the selected clock source has a higher frequency than allowed under present operating conditions.
See “Speed” on page 229.
6.5.3 OSCCAL0 – Oscillator Calibration Register
Although temperature slope and frequency are in part controlled by registers OSCTCAL0A and OSCTCAL0B it is
possible to replace factory calibration by simply writing to this register alone. Optimal accuracy is achieved when
OSCCAL0, OSCTAL0A and OSCTCAL0B are calibrated together.
• Bits 7:0 – CAL0[7:0]: Oscillator Calibration Value
The oscillator calibration register is used to trim the internal 8MHz oscillator and to remove process variations from
the oscillator frequency. A pre-programmed calibration value is automatically written to this register during chip
reset, giving the factory calibrated frequency specified in Table 24-2 on page 230.
The application software can write this register to change the oscillator frequency. The oscillator can be calibrated
to frequencies specified in Table 24-2 on page 230. Calibration outside that range is not guaranteed.
The lowest oscillator frequency is reached by programming these bits to zero. Increasing the register value
increases the oscillator frequency. A typical frequency response curve is shown in “Calibrated Oscillator Frequency
(Nominal = 8MHz) vs. OSCCAL Value” on page 273.
Note that this oscillator is used to time EEPROM and Flash write accesses, and write times will be affected accordingly.
Do not calibrate to more than 8.8MHz if EEPROM or Flash is to be written. Otherwise, the EEPROM or Flash
write may fail.
To ensure stable operation of the MCU the calibration value should be changed in small steps. A step change in
frequency of more than 2% from one cycle to the next can lead to unpredictable behavior. Also, the difference
between two consecutive register values should not exceed 0x20. If these limits are exceeded the MCU must be
kept in reset during changes to clock frequency.
1001
Reserved
1010
1011
1100
1101
1110
1111
Table 6-4. Clock Prescaler Select (Continued)
CLKPS3 CLKPS2 CLKPS1 CLKPS0 Clock Division Factor
Bit 7 6 5 4 3 2 1 0
(0x63) CAL07 CAL06 CAL05 CAL04 CAL03 CAL02 CAL01 CAL00 OSCCAL0
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value Device Specific Calibration ValueATtiny1634 [DATASHEET] 33
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
6.5.4 OSCTCAL0A – Oscillator Temperature Calibration Register A
This register is used for changing the temperature slope and frequency of the internal 8MHz oscillator. A pre-programmed
calibration value is automatically written to this register during chip reset, giving the factory calibrated
frequency specified in Table 24-2 on page 230.
This register need not be updated if factory defaults in OSCCAL0 are overwritten although optimal accuracy is
achieved when OSCCAL0, OSCTAL0A and OSCTCAL0B are calibrated together.
• Bit 7 – Sign of Oscillator Temperature Calibration Value
This is the sign bit of the calibration data.
• Bits 6:0 – Oscillator Temperature Calibration Value
These bits contain the numerical value of the calibration data.
6.5.5 OSCTCAL0B – Oscillator Temperature Calibration Register B
A pre-programmed calibration value is automatically written to this register during chip reset, giving the factory calibrated
frequency specified in Table 24-2 on page 230.
This register need not be updated if factory defaults in OSCCAL0 are overwritten although optimal accuracy is
achieved when OSCCAL0, OSCTAL0A and OSCTCAL0B are calibrated together.
• Bit 7 – Temperature Compensation Enable
When this bit is set the contents of registers OSCTCAL0A and OSCTCAL0B are used for calibration. When this bit
is cleared the temperature compensation hardware is disabled and registers OSCTCAL0A and OSCTCAL0B have
no effect on the frequency of the internal 8MHz oscillator.
Note that temperature compensation has a large effect on oscillator frequency and, hence, when enabled or disabled
the OSCCAL0 register must also be adjusted to compensate for this effect.
• Bits 6:0 – Temperature Compensation Step Adjust
These bits control the step size of the calibration data in OSCTCAL0A. The largest step size is achieved for 0x00
and smallest step size for 0x7F.
6.5.6 OSCCAL1 – Oscillator Calibration Register
• Bits 7:2 – Res: Reserved Bits
These bits are reserved and will always read zero.
Bit 7 6 5 4 3 2 1 0
(0x64) Oscillator Temperature Calibration Data OSCTCAL0A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value Device Specific Calibration Value
Bit 7 6 5 4 3 2 1 0
(0x65) Oscillator Temperature Calibration Data OSCTCAL0B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value Device Specific Calibration Value
Bit 7 6 5 4 3 2 1 0
(0x66) – – – – – – CAL11 CAL10 OSCCAL1
Read/Write R R R R R R R/W R/W
Initial Value Device Specific Calibration ValueATtiny1634 [DATASHEET] 34
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
• Bits 1:0 – CAL1[1:0]: Oscillator Calibration Value
The oscillator calibration register is used to trim the internal 32kHz oscillator and to remove process variations from
the oscillator frequency. A pre-programmed calibration value is automatically written to this register during chip
reset, giving the factory calibrated frequency as specified in Table 24-3 on page 231.
The application software can write this register to change the oscillator frequency. The oscillator can be calibrated
to frequencies as specified in Table 24-3 on page 231. Calibration outside that range is not guaranteed.
The lowest oscillator frequency is reached by programming these bits to zero. Increasing the register value
increases the oscillator frequency.
7. Power Management and Sleep Modes
The high performance and industry leading code efficiency makes the AVR microcontrollers an ideal choise for low
power applications. In addition, sleep modes enable the application to shut down unused modules in the MCU,
thereby saving power. The AVR provides various sleep modes allowing the user to tailor the power consumption to
the application’s requirements.
7.1 Sleep Modes
Figure 6-1 on page 25 presents the different clock systems and their distribution in ATtiny1634. The figure is helpful
in selecting an appropriate sleep mode. Table 7-1 shows the different sleep modes and the sources that may be
used for wake up.
Note: 1. Start frame detection, only.
2. Start condition, only.
3. Address match interrupt, only.
4. For INT0 level interrupt, only.
To enter a sleep mode, the SE bit in MCUCR must be set and a SLEEP instruction must be executed. The SMn
bits in MCUCR select which sleep mode will be activated by the SLEEP instruction. See Table 7-2 on page 37 for
a summary.
If an enabled interrupt occurs while the MCU is in a sleep mode, the MCU wakes up. The MCU is then halted for
four cycles in addition to the start-up time, executes the interrupt routine, and resumes execution from the instruction
following SLEEP. The contents of the Register File and SRAM are unaltered when the device wakes up from
sleep. If a reset occurs during sleep mode, the MCU wakes up and executes from the Reset Vector.
Table 7-1. Active Clock Domains and Wake-up Sources in Different Sleep Modes
Sleep Mode
Oscillators Active Clock Domains Wake-up Sources Main Clock Source Enabled clkCPU clkFLASH clkIO clkADC Watchdog Interrupt INT0 and Pin Change SPM/EEPROM Ready Interrupt ADC Interrupt USART USI
TWI Slave
Other I/O
Idle X X X X X X X X X X X
ADC Noise
Reduction X X X X (4) X X X (1) X (2) X (3)
Standby X X X (4) X (1) X (2) X (3)
Power-down X X (4) X (1) X (2) X (3)ATtiny1634 [DATASHEET] 35
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Note that if a level triggered interrupt is used for wake-up the changed level must be held for some time to wake up
the MCU (and for the MCU to enter the interrupt service routine). See “External Interrupts” on page 48 for details.
7.1.1 Idle Mode
This sleep mode basically halts clkCPU and clkFLASH, while allowing other clocks to run. In Idle Mode, the CPU is
stopped but the following peripherals continue to operate:
• Watchdog and interrupt system
• Analog comparator, and ADC
• USART, TWI, and timer/counters
Idle mode allows the MCU to wake up from external triggered interrupts as well as internal ones, such as Timer
Overflow. If wake-up from the analog comparator interrupt is not required, the analog comparator can be powered
down by setting the ACD bit in ACSRA. See “ACSRA – Analog Comparator Control and Status Register” on page
182. This will reduce power consumption in Idle mode.
If the ADC is enabled, a conversion starts automatically when this mode is entered.
7.1.2 ADC Noise Reduction Mode
This sleep mode halts clkI/O, clkCPU, and clkFLASH, while allowing other clocks to run. In ADC Noise Reduction
mode, the CPU is stopped but the following peripherals continue to operate:
• Watchdog (if enabled), and external interrupts
• ADC
• USART start frame detector, and TWI
This improves the noise environment for the ADC, enabling higher resolution measurements. If the ADC is
enabled, a conversion starts automatically when this mode is entered.
The following events can wake up the MCU:
• Watchdog reset, external reset, and brown-out reset
• External level interrupt on INT0, and pin change interrupt
• ADC conversion complete interrupt, and SPM/EEPROM ready interrupt
• USI start condition, USART start frame detection, and TWI address match
7.1.3 Power-Down Mode
This sleep mode halts all generated clocks, allowing operation of asynchronous modules, only. In Power-down
Mode the oscillator is stopped, while the following peripherals continue to operate:
• Watchdog (if enabled), external interrupts
The following events can wake up the MCU:
• Watchdog reset, external reset, and brown-out reset
• External level interrupt on INT0, and pin change interrupt
• USI start condition, USART start frame detection, and TWI address matchATtiny1634 [DATASHEET] 36
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
7.1.4 Standby Mode
Standby Mode is identical to power-down, with the exception that the oscillator is kept running. From Standby
mode, the device wakes up in six clock cycles.
7.2 Power Reduction Register
The Power Reduction Register (PRR), see “PRR – Power Reduction Register” on page 38, provides a method to
reduce power consumption by stopping the clock to individual peripherals. When the clock for a peripheral is
stopped then:
• The current state of the peripheral is frozen.
• The associated registers can not be read or written.
• Resources used by the peripheral will remain occupied.
The peripheral should in most cases be disabled before stopping the clock. Clearing the PRR bit wakes up the
peripheral and puts it in the same state as before shutdown.
Peripheral shutdown can be used in Idle mode and Active mode to significantly reduce the overall power consumption.
In all other sleep modes, the clock is already stopped.
7.3 Minimizing Power Consumption
There are several issues to consider when trying to minimize the power consumption in an AVR controlled system.
In general, sleep modes should be used as much as possible, and the sleep mode should be selected so that as
few as possible of the device’s functions are operating. All functions not needed should be disabled. In particular,
the following modules may need special consideration when trying to achieve the lowest possible power
consumption.
7.3.1 Analog to Digital Converter
If enabled, the ADC will be enabled in all sleep modes. To save power, the ADC should be disabled before entering
any sleep mode. When the ADC is turned off and on again, the next conversion will be an extended conversion.
See “Analog to Digital Converter” on page 185 for details on ADC operation.
7.3.2 Analog Comparator
When entering Idle mode, the Analog Comparator should be disabled if not used. When entering ADC Noise
Reduction mode, the Analog Comparator should be disabled. In the other sleep modes, the Analog Comparator is
automatically disabled. However, if the Analog Comparator is set up to use the Internal Voltage Reference as
input, the Analog Comparator should be disabled in all sleep modes. Otherwise, the Internal Voltage Reference will
be enabled, independent of sleep mode. See “Analog Comparator” on page 181 for details on how to configure the
Analog Comparator.
7.3.3 Brown-out Detector
If the Brown-out Detector is not needed in the application, this module should be turned off. If the Brown-out Detector
is enabled by the BODPD Fuses, it will be enabled in all sleep modes, and hence, always consume power. In
the deeper sleep modes, this will contribute significantly to the total current consumption. If the Brown-out Detector
is needed in the application, this module can also be set to Sampled BOD mode to save power. See “Brown-Out
Detection” on page 41 for details on how to configure the Brown-out Detector.
7.3.4 Internal Voltage Reference
The Internal Voltage Reference will be enabled when needed by the Brown-out Detection, the Analog Comparator
or the ADC. If these modules are disabled as described in the sections above, the internal voltage reference will be
disabled and it will not be consuming power. When turned on again, the user must allow the reference to start upATtiny1634 [DATASHEET] 37
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
before the output is used. If the reference is kept on in sleep mode, the output can be used immediately. See Internal
Bandgap Reference in Table 24-5 on page 231 for details on the start-up time.
7.3.5 Watchdog Timer
If the Watchdog Timer is not needed in the application, this module should be turned off. If the Watchdog Timer is
enabled, it will be enabled in all sleep modes, and hence, always consume power. In the deeper sleep modes, this
will contribute to the total current consumption. See “Watchdog Timer” on page 43 for details on how to configure
the Watchdog Timer.
7.3.6 Port Pins
When entering a sleep mode, all port pins should be configured to use minimum power. The most important thing
is then to ensure that no pins drive resistive loads. In sleep modes where both the I/O clock (clkI/O) and the ADC
clock (clkADC) are stopped, the input buffers of the device will be disabled. This ensures that no power is consumed
by the input logic when not needed. In some cases, the input logic is needed for detecting wake-up conditions, and
it will then be enabled. See the section “Digital Input Enable and Sleep Modes” on page 58 for details on which pins
are enabled. If the input buffer is enabled and the input signal is left floating or has an analog signal level close to
VCC/2, the input buffer will use excessive power.
For analog input pins, the digital input buffer should be disabled at all times. An analog signal level close to VCC/2
on an input pin can cause significant current even in active mode. Digital input buffers can be disabled by writing to
the Digital Input Disable Register (DIDR0). See “DIDR0 – Digital Input Disable Register 0” on page 200 for details.
7.3.7 On-chip Debug System
If the On-chip debug system is enabled by the DWEN Fuse and the chip enters sleep mode, the main clock source
is enabled and hence always consumes power. In the deeper sleep modes, this will contribute significantly to the
total current consumption.
7.4 Register Description
7.4.1 MCUCR – MCU Control Register
The MCU Control Register contains control bits for power management.
• Bits 7, 3:2 – Res: Reserved Bits
These bits are reserved and will always read zero.
• Bits 6:5 – SM[1:0]: Sleep Mode Select Bits 1 and 0
These bits select between available sleep modes, as shown in Table 7-2.
Bit 7 6 5 4 3 2 1 0
0x36 (0x56) – SM1 SM0 SE – – ISC01 ISC00 MCUCR
Read/Write R R/W R/W R/W R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 7-2. Sleep Mode Select
SM1 SM0 Sleep Mode
0 0 Idle
0 1 ADC Noise Reduction
1 0 Power-down
1 1 Standby(1)ATtiny1634 [DATASHEET] 38
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Note: 1. Only recommended with external crystal or resonator selected as clock source
• Bit 4 – SE: Sleep Enable
The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP instruction is executed.
To avoid the MCU entering the sleep mode unless it is the programmer’s purpose, it is recommended to
write the Sleep Enable (SE) bit to one just before the execution of the SLEEP instruction and to clear it immediately
after waking up.
7.4.2 PRR – Power Reduction Register
The Power Reduction Register provides a method to reduce power consumption by allowing peripheral clock signals
to be disabled.
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit and will always read zero.
• Bit 6 – PRTWI: Power Reduction Two-Wire Interface
Writing a logic one to this bit shuts down the Two-Wire Interface module.
• Bit 5 – PRTIM1: Power Reduction Timer/Counter1
Writing a logic one to this bit shuts down the Timer/Counter1 module. When the Timer/Counter1 is enabled, operation
will continue like before the shutdown.
• Bit 4 – PRTIM0: Power Reduction Timer/Counter0
Writing a logic one to this bit shuts down the Timer/Counter0 module. When the Timer/Counter0 is enabled, operation
will continue like before the shutdown.
• Bit 3 – PRUSI: Power Reduction USI
Writing a logic one to this bit shuts down the USI by stopping the clock to the module. When waking up the USI
again, the USI should be re initialized to ensure proper operation.
• Bit 2 – PRUSART1: Power Reduction USART1
Writing a logic one to this bit shuts down the USART1 module. When the USART1 is enabled, operation will continue
like before the shutdown.
• Bit 1 – PRUSART0: Power Reduction USART0
Writing a logic one to this bit shuts down the USART0 module. When the USART0 is enabled, operation will continue
like before the shutdown.
• Bit 0 – PRADC: Power Reduction ADC
Writing a logic one to this bit shuts down the ADC. The ADC must be disabled before shut down. The analog comparator
cannot be used when the ADC is shut down.
Bit 7 6 5 4 3 2 1 0
0x34 (0x54) – PRTWI PRTIM1 PRTIM0 PRUSI PRUSART1 PRUSART0 PRADC PRR
Read/Write R R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny1634 [DATASHEET] 39
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
8. System Control and Reset
8.1 Resetting the AVR
During reset, all I/O registers are set to their initial values, and the program starts execution from the Reset Vector.
The instruction placed at the Reset Vector should be a JMP (two-word, direct jump) instruction to the reset handling
routine, although other one- or two-word jump instructions can be used. If the program never enables an
interrupt source, the interrupt vectors are not used, and regular program code can be placed at these locations.
The circuit diagram in Figure 8-1 shows the reset logic. Electrical parameters of the reset circuitry are defined in
section “System and Reset” on page 231.
Figure 8-1. Reset Logic
The I/O ports of the AVR are immediately reset to their initial state when a reset source goes active. This does not
require any clock source to be running.
After all reset sources have gone inactive, a delay counter is invoked, stretching the internal reset. This allows the
power to reach a stable level before normal operation starts.
8.2 Reset Sources
The ATtiny1634 has four sources of reset:
• Power-on Reset. The MCU is reset when the supply voltage is below the Power-on Reset threshold (VPOT)
• External Reset. The MCU is reset when a low level is present on the RESET pin for longer than the minimum
pulse length when RESET function is enabled
• Watchdog Reset. The MCU is reset when the Watchdog Timer period expires and the Watchdog is enabled
• Brown-out Reset. The MCU is reset when the supply voltage VCC is below the Brown-out Reset threshold (VBOT)
and the Brown-out Detector is enabled
8.2.1 Power-on Reset
A Power-on Reset (POR) pulse is generated by an on-chip detection circuit. The detection level is defined in “System
and Reset” on page 231. The POR is activated whenever VCC is below the detection level. The POR circuit can
be used to trigger the Start-up Reset, as well as to detect a failure in supply voltage.
A Power-on Reset (POR) circuit ensures that the device is reset from Power-on. Reaching the Power-on Reset
threshold voltage invokes the delay counter, which determines how long the device is kept in reset after VCC rise.
The reset signal is activated again, without any delay, when VCC decreases below the detection level.
DATA BUS
RESET FLAG REGISTER RESET FLAG REGISTER
(RSTFLR) (RSTFLR)
POWER-ON POWER-ON RESET CIRCUIT RESET CIRCUIT
PULL-UP PULL-UP
RESISTOR RESISTOR
BODLEVEL2...0 BODLEVEL2...0
VCC
SPIKE
FILTER RESET
EXTERNAL EXTERNAL
RESET CIRCUIT RESET CIRCUIT
BROWN OUT BROWN OUT RESET CIRCUIT RESET CIRCUIT
RSTDISBL RSTDISBL
WATCHDOG WATCHDOG
TIMER
DELAY
COUNTERS COUNTERS
S
R
Q
WATCHDOG WATCHDOG OSCILLATOR OSCILLATOR
CLOCK GENERATOR GENERATOR
BORF
PORF
EXTRF
WDRF
INTERNAL INTERNAL
RESET
CK
TIMEOUT TIMEOUT
COUNTER RESET COUNTER RESETATtiny1634 [DATASHEET] 40
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
Figure 8-2. MCU Start-up, RESET Tied to VCC
Figure 8-3. MCU Start-up, RESET Extended Externally
8.2.2 External Reset
An External Reset is generated by a low level on the RESET pin if enabled. Reset pulses longer than the minimum
pulse width (see section “System and Reset” on page 231) will generate a reset, even if the clock is not running.
Shorter pulses are not guaranteed to generate a reset. When the applied signal reaches the Reset Threshold Voltage
– VRST – on its positive edge, the delay counter starts the MCU after the time-out period – tTOUT – has expired.
External reset is ignored during Power-on start-up count. After Power-on reset the internal reset is extended only if
RESET pin is low when the initial Power-on delay count is complete. See Figure 8-2 and Figure 8-3.
Figure 8-4. External Reset During Operation
V
TIME-OUT
RESET
RESET
TOUT
INTERNAL
t
VPOT
VRST
CC
V
TIME-OUT
TOUT
TOUT
INTERNAL
CC
t
VPOT
VRST
> t
RESET
RESET
CCATtiny1634 [DATASHEET] 41
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
8.2.3 Watchdog Reset
When the Watchdog times out, it will generate a short reset pulse. On the falling edge of this pulse, the delay timer
starts counting the time-out period tTOUT. See page 43 for details on operation of the Watchdog Timer and Table
24-5 on page 231 for details on reset time-out.
Figure 8-5. Watchdog Reset During Operation
8.2.4 Brown-Out Detection
The Brown-Out Detection (BOD) circuit monitors that the VCC level is kept above a configurable trigger level, VBOT.
When the BOD is enabled, a BOD reset will be given when VCC falls and remains below the trigger level for the
length of the detection time, tBOD. The reset is kept active until VCC again rises above the trigger level.
Figure 8-6. Brown-out Detection reset.
The BOD circuit will not detect a drop in VCC unless the voltage stays below the trigger level for the detection time,
tBOD (see “System and Reset” on page 231).
The BOD circuit has three modes of operation:
• Disabled: In this mode of operation VCC is not monitored and, hence, it is recommended only for applications
where the power supply remains stable.
CK
CC
VCC
TIME-OUT
INTERNAL
RESET
VBOTVBOT+
t
TOUT
t
BODATtiny1634 [DATASHEET] 42
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
• Enabled: In this mode the VCC level is continuously monitored. If VCC drops below VBOT for at least tBOD a
brown-out reset will be generated.
• Sampled: In this mode the VCC level is sampled on each negative edge of a 1kHz clock that has been derived
from the 32kHz ULP oscillator. Between each sample the BOD is turned off. Compared to the mode where BOD
is constantly enabled this mode of operation reduces power consumption but fails to detect drops in VCC
between two positive edges of the 1kHz clock. When a brown-out is detected in this mode, the BOD circuit is set
to enabled mode to ensure that the device is kept in reset until VCC has risen above VBOT . The BOD will return
to sampled mode after reset has been released and the fuses have been read in.
The BOD mode of operation is selected using BODACT and BODPD fuse bits. The BODACT fuse bits determine
how the BOD operates in active and idle mode, as shown in Table 8-1.
The BODPD fuse bits determine the mode of operation in all sleep modes except idle mode, as shown in Table 8-
2.
See “Fuse Bits” on page 209.
8.3 Internal Voltage Reference
ATtiny1634 features an internal bandgap reference. This reference is used for Brown-out Detection, and it can be
used as an input to the Analog Comparator or the ADC. The bandgap voltage varies with supply voltage and
temperature.
8.3.1 Voltage Reference Enable Signals and Start-up Time
The voltage reference has a start-up time that may influence the way it should be used. The start-up time is given
in “System and Reset” on page 231. To save power, the reference is not always turned on. The reference is on
during the following situations:
1. When the BOD is enabled (see “Brown-Out Detection” on page 41).
2. When the internal reference is connected to the Analog Comparator (by setting the ACBG bit in ACSRA).
3. When the ADC is enabled.
Thus, when the BOD is not enabled, after setting the ACBG bit or enabling the ADC, the user must always allow
the reference to start up before the output from the Analog Comparator or ADC is used. To reduce power conTable
8-1. Setting BOD Mode of Operation in Active and Idle Modes
BODACT1 BODACT0 Mode of Operation
0 0 Reserved
0 1 Sampled
1 0 Enabled
1 1 Disabled
Table 8-2. Setting BOD Mode of Operation in Sleep Modes Other Than Idle
BODPD1 BODPD0 Mode of Operation
0 0 Reserved
0 1 Sampled
1 0 Enabled
1 1 DisabledATtiny1634 [DATASHEET] 43
Atmel-8303H-AVR-ATtiny1634-Datasheet_02/2014
sumption in Power-down mode, the user can avoid the three conditions above to ensure that the reference is
turned off before entering Power-down mode.
8.4 Watchdog Timer
The Watchdog Timer is clocked from the internal 32kHz ultra low power oscillator (see page 27). By controlling the
Watchdog Timer prescaler, the Watchdog Reset interval can be adjusted as shown in Table 8-5 on page 46. The
WDR – Watchdog Reset – instruction resets the Watchdog Timer. The Watchdog Timer is also reset when it is disabled
and when a Chip Reset occurs. Ten different clock cycle periods can be selected to determine the reset
period. If the reset period expires without another Watchdog Reset, the ATtiny1634 resets and executes from the
Reset Vector. For timing details on the Watchdog Reset, refer to Table 8-5 on page 46.
The Wathdog Timer can also be configured to generate an interrupt instead of a reset. This can be very helpful
when using the Watchdog to wake-up from Power-down.
To prevent unintentional disabling of the Watchdog or unintentional change of time-out period, two different safety
levels are selected by the fuse WDTON as shown in Table 8-3 See “Timed Sequences for Changing the Configuration
of the Watchdog Timer” on page 43 for details.
Figure 8-7. Watchdog Timer
8.4.1 Timed Sequences for Changing the Configuration of the Watchdog Timer
The sequence for changing configuration differs slightly between the two safety levels. Separate procedures are
described for each level.