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Farnell PDF
Atmel QTouch Library User Guide - Farnell Element 14
Atmel QTouch Library User Guide - 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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Rev. 8207L-AT42-05/12
Atmel QTouch Library
User Guide
Supports QTouch® and QMatrix® acquisition for Keys, Sliders
and Rotors 2 8207L-AT42-05/12
Rev. 8207L-AT42-05/12
Table of Contents
TABLE OF CONTENTS ..............................................................................................................................2
1 PREFACE..............................................................................................................................................8
2 INTRODUCTION .................................................................................................................................9
3 OVERVIEW ........................................................................................................................................10
4 ABBREVIATIONS AND DEFINITIONS.........................................................................................11
4.1 DEFINITIONS...................................................................................................................................11
5 GENERIC QTOUCH LIBRARIES...................................................................................................12
5.1 INTRODUCTION...............................................................................................................................12
5.2 ACQUISITION METHODS .................................................................................................................13
5.2.1 QTouch acquisition method...................................................................................................13
5.2.1.1 Sensor schematics for a QTouch acquisition method design............................................................ 14
5.2.2 QMatrix acquisition method ..................................................................................................14
5.2.3 Sensor schematics for a QMatrix acquisition method design................................................15
5.3 GLOBAL SETTINGS COMMON TO ALL SENSORS OF A SPECIFIC ACQUISITION METHOD......................15
5.3.1 Recalibration Threshold ........................................................................................................16
5.3.2 Detect Integration..................................................................................................................16
5.3.3 Drift Hold Time .....................................................................................................................16
5.3.4 Maximum ON Duration .........................................................................................................17
5.3.5 Positive / Negative Drift ........................................................................................................17
5.3.6 Positive Recalibration Delay .................................................................................................18
5.4 SENSOR SPECIFIC SETTINGS ............................................................................................................18
5.4.1 Detect threshold.....................................................................................................................18
5.4.2 Hysteresis...............................................................................................................................18
5.4.3 Position Resolution................................................................................................................19
5.4.4 Position Hysteresis ................................................................................................................19
5.4.5 Adjacent Key Suppression (AKS)...........................................................................................20
5.5 USING THE SENSORS.......................................................................................................................20
5.5.1 Avoiding Cross-talk ...............................................................................................................20
5.5.2 Multiple measurements..........................................................................................................20
5.5.3 Guard Channel ......................................................................................................................21
5.6 QTOUCH API AND USAGE..............................................................................................................22
5.6.1 QTouch Library API..............................................................................................................22
5.6.2 touch_api.h - public header file.............................................................................................22
5.6.3 Type Definitions and enumerations used in the library.........................................................22
5.6.3.1 Typedefs........................................................................................................................................... 22
5.6.3.2 Enumerations ................................................................................................................................... 22
5.6.3.2.1 sensor_type_t.............................................................................................................................. 22
5.6.3.2.2 aks_group_t................................................................................................................................ 23
5.6.3.2.3 channel_t.................................................................................................................................... 23
5.6.3.2.4 hysteresis_t................................................................................................................................. 23
5.6.3.2.5 resolution_t................................................................................................................................. 24
5.6.3.2.6 recal_threshold_t........................................................................................................................ 24
5.6.4 Data structures......................................................................................................................25
5.6.4.1 qt_touch_status_t.............................................................................................................................. 25
5.6.4.2 qt_touch_lib_config_data_t.............................................................................................................. 25
5.6.4.3 qt_touch_lib_measure_data_t........................................................................................................... 26
5.6.4.4 qt_burst_lengths............................................................................................................................... 26
5.6.4.5 tag_sensor_t ..................................................................................................................................... 27
5.6.4.6 qt_lib_siginfo_t ................................................................................................................................ 27
5.6.5 Public Functions....................................................................................................................283
5.6.5.1 qt_set_parameters............................................................................................................................. 28
5.6.5.2 qt_enable_key .................................................................................................................................. 29
5.6.5.3 qt_enable_rotor ................................................................................................................................ 29
5.6.5.4 qt_enable_slider ............................................................................................................................... 30
5.6.5.5 qt_init_sensing ................................................................................................................................. 30
5.6.5.6 qt_measure_sensors.......................................................................................................................... 31
5.6.5.7 qt_calibrate_sensing......................................................................................................................... 31
5.6.5.8 qt_reset_sensing ............................................................................................................................... 32
5.6.5.9 qt_get_sensor_delta.......................................................................................................................... 32
5.6.5.10 qt_get_library_sig ........................................................................................................................ 32
5.6.6 Sequence of Operations and Using the API...........................................................................33
5.6.6.1 Channel Numbering ......................................................................................................................... 33
5.6.6.1.1 Channel numbering when using QTouch acquisition method .................................................... 33
5.6.6.1.2 Channel numbering when using QMatrix acquisition method ................................................... 39
5.6.6.2 Sensor Numbering............................................................................................................................ 41
5.6.6.3 Filtering Signal Measurements......................................................................................................... 42
5.6.6.4 Allocating unused Port Pins for User Application............................................................................ 43
5.6.6.5 Disabling and Enabling of Pull-up for AVR devices........................................................................ 44
5.6.7 Constraints.............................................................................................................................44
5.6.7.1 QTouch acquisition method constraints........................................................................................... 44
5.6.7.2 QMatrix acquisition method constraints........................................................................................... 45
5.6.7.3 Design Guidelines for QMatrix acquisition method systems ........................................................... 46
5.6.8 Frequency of operation (Vs) Charge cycle/dwell cycle times: ..............................................46
5.6.9 Interrupts...............................................................................................................................47
5.6.10 Integrating QTouch libraries in your application .................................................................48
5.6.10.1 Directory structure of the library files.......................................................................................... 48
5.6.10.2 Integrating QTouch acquisition method libraries in your application.......................................... 50
5.6.10.2.1 Example for 8bit AVR ............................................................................................................. 52
5.6.10.2.2 Example for ATSAM ............................................................................................................... 54
5.6.10.2.3 Checklist of items for integrating QTouch acquisition method libraries.................................. 55
5.6.10.3 Integrating QMatrix acquisition method libraries in your application ......................................... 55
5.6.10.3.1 Example for 8bit AVR ............................................................................................................. 55
5.6.10.3.2 Example for 32bit AVR ........................................................................................................... 62
5.6.10.3.3 Checklist of items for integrating QMatrix Capacitive sensing libraries.................................. 66
5.6.10.4 Common checklist items.............................................................................................................. 66
5.6.10.4.1 Configuring the stack size for the application .......................................................................... 66
5.6.11 Example project files .............................................................................................................67
5.6.11.1 Using the Sample projects ........................................................................................................... 68
5.6.11.2 Example applications for QTouch acquisition method libraries.................................................. 68
5.6.11.2.1 Selecting the right configuration .............................................................................................. 68
5.6.11.2.2 Changing the settings to match your device ............................................................................. 69
5.6.11.2.3 Changing the library configuration parameters ........................................................................ 70
5.6.11.2.4 Using the example projects ...................................................................................................... 72
5.6.11.3 Example applications for QMatrix acquisition method libraries.................................................. 73
5.6.11.3.1 Selecting the right configuration .............................................................................................. 73
5.6.11.3.2 Changing the library configuration parameters ........................................................................ 74
5.6.11.3.3 Using the example projects ...................................................................................................... 75
5.6.11.4 Adjusting the Stack size when using IAR IDE ............................................................................ 76
5.6.11.5 Optimization levels...................................................................................................................... 76
5.6.11.6 Debug Support in Example applications...................................................................................... 77
5.6.11.6.1 Debug Support in the sample applications for EVK2080 and QT600 boards .......................... 77
5.6.11.6.2 How to turn on the debug option.............................................................................................. 77
5.6.11.6.3 Debug Interface if USB Bridge board is not available ............................................................. 78
5.7 LIBRARY VARIANTS .......................................................................................................................79
5.7.1 QTouch Acquisition method library variants.........................................................................79
5.7.1.1 Introduction...................................................................................................................................... 79
5.7.1.2 Support for different compiler tool chains........................................................................................ 79
5.7.1.3 QTouch Acquisition method library naming conventions................................................................ 79
5.7.1.3.1 Naming convention for libraries to be used with GCC tool chain.............................................. 79
5.7.1.3.2 Naming convention for libraries to be used with IAR Embedded Workbench........................... 80
5.7.1.4 QTouch acquisition method library variants .................................................................................... 804 8207L-AT42-05/12
5.7.1.5 Port combinations supported for SNS and SNSK pin configurations............................................... 81
5.7.1.5.1 Tips on pin assignments for the sensor design using one pair of SNS/SNSK ports ................... 81
5.7.1.5.2 Port combinations supported for two port pair SNS and SNSK pin configurations................... 83
5.7.1.6 Sample applications and Memory requirements for QTouch acquisition method libraries.............. 84
5.7.2 QMatrix acquisition method library variants........................................................................84
5.7.2.1 Introduction...................................................................................................................................... 84
5.7.2.2 Support for different compiler tool chains........................................................................................ 84
5.7.2.3 QMatrix Acquisition method library naming conventions............................................................... 84
5.7.2.4 QMatrix acquisition method library variants.................................................................................... 87
5.7.2.4.1 Devices supported for QMatrix Acquisition............................................................................... 87
5.8 PIN CONFIGURATION FOR QTOUCH LIBRARIES .............................................................................87
5.8.1 Pin Configuration for QTouch Acquisition Method ..............................................................87
5.8.1.1 Rules for configurable SNS-SNSK Mask Generation...................................................................... 88
5.8.1.1.1 Example for 8 channel interport mask Calculation with one port pair ....................................... 89
5.8.1.1.2 Example for 8 channel intraport mask Calculation with two port pairs...................................... 90
5.8.1.1.3 Example for 12 channel intraport-interport mask Calculation with two port pairs.................... 91
5.8.1.1.4 Example for 16 channel intreport-interport mask Calculation with two port pairs.................... 92
5.8.1.2 How to Use QTouch Studio For Pin Configurability ....................................................................... 93
5.8.2 Pin Configuration for QMatrix Acquisition Method............................................................101
5.8.2.1 Configuration Rules: ...................................................................................................................... 101
5.8.2.2 How to use QTouch Studio for Pin Configurability:...................................................................... 102
5.9 MISRA COMPLIANCE REPORT.....................................................................................................109
5.9.1 What is covered ...................................................................................................................110
5.9.2 Target Environment.............................................................................................................110
5.9.3 Deviations from MISRA C Standards..................................................................................110
5.9.3.1 QTouch acquisition method libraries ............................................................................................. 110
5.9.3.2 QMatrix acquisition method libraries............................................................................................. 111
5.10 KNOWN ISSUES.............................................................................................................................111
5.11 CHECKLIST...................................................................................................................................112
6 DEVICE SPECIFIC LIBRARIES ...................................................................................................113
6.1 INTRODUCTION.............................................................................................................................113
6.2 DEVICES SUPPORTED ....................................................................................................................113
6.3 QTOUCH LIBRARY FOR AT32UC3L DEVICES ..............................................................................113
6.3.1 Salient Features of QTouch Library for UC3L....................................................................113
6.3.1.1 QMatrix method sensor.................................................................................................................. 113
6.3.1.2 QTouch method sensor................................................................................................................... 113
6.3.1.3 Autonomous QTouch sensor.......................................................................................................... 114
6.3.1.4 Additional Features........................................................................................................................ 114
6.3.2 Device variants supported for UC3L...................................................................................114
6.3.3 Development tool support for UC3L ...................................................................................114
Table 8 Development tool support for UC3L QTouch Library ................................................................... 114
6.3.4 Overview of QTouch Library API for UC3L .......................................................................115
Figure 35 Overview diagram of QTouch Library for UC3L ....................................................................... 115
6.3.5 Acquisition method support for UC3L.................................................................................116
Table 9 Acquisition method specific API.................................................................................................... 116
6.3.6 API State machine for UC3L ...............................................................................................116
Figure 36 State Diagram of QTouch Library for UC3L .............................................................................. 117
6.3.7 QMatrix method sensor operation for UC3L.......................................................................117
6.3.7.1 QMatrix method pin selection for UC3L........................................................................................ 117
Table 10 QMatrix Resistive drive pin option .............................................................................................. 118
6.3.7.2 QMatrix method Schematic for UC3L........................................................................................... 118
6.3.7.2.1 Internal Discharge mode .......................................................................................................... 118
6.3.7.2.2 External Discharge mode ......................................................................................................... 119
6.3.7.2.3 SMP Discharge Mode .............................................................................................................. 119
6.3.7.2.4 VDIVEN Voltage Divider Enable option................................................................................. 119
6.3.7.2.5 SYNC pin option...................................................................................................................... 119
Figure 37 QMatrix method schematic ......................................................................................................... 120
6.3.7.3 QMatrix method hardware resource requirement for UC3L .......................................................... 121
6.3.7.4 QMatrix method Channel and Sensor numbering for UC3L.......................................................... 1215
Figure 38 QMatrix channel numbering for UC3L....................................................................................... 121
6.3.7.5 QMatrix method API Flow for UC3L............................................................................................ 121
Figure 39 QMatrix API Flow diagram for UC3L........................................................................................ 122
6.3.7.6 QMatrix method Disable and Re-enable Sensor for UC3L............................................................ 124
6.3.8 QTouch Group A/B method sensor operation for UC3L .....................................................124
6.3.8.1 QTouch Group A/B method pin selection for UC3L...................................................................... 124
Table 11 QTouch Resistive drive pin option ............................................................................................... 125
6.3.8.2 QTouch Group A/B method Schematic for UC3L ......................................................................... 125
6.3.8.2.1 Resistive Drive option.............................................................................................................. 125
6.3.8.2.2 SYNC pin option...................................................................................................................... 125
Figure 40 QTouch Group A/B and Autonomous QTouch schematic arrangement ..................................... 126
6.3.8.3 QTouch Group A/B method hardware resource requirement for UC3L ........................................ 126
6.3.8.4 QTouch Group A/B method Channel and Sensor numbering for UC3L........................................ 127
Figure 41 QTouch method Channel/Sensor numbering............................................................................... 127
Figure 42 QTouch method Channel/Sensor numbering when Group A and B are used together................ 127
6.3.8.5 QTouch Group A/B method API Flow for UC3L.......................................................................... 128
Figure 43 QTouch method API Flow diagram ............................................................................................ 129
6.3.8.6 QTouch Group A/B method Disable and Re-enable Sensor for UC3L.......................................... 130
6.3.9 Autonomous QTouch sensor operation for UC3L ...............................................................130
6.3.9.1 Autonomous QTouch Sensor pin selection for UC3L.................................................................... 130
6.3.9.2 Autonomous QTouch sensor Schematic for UC3L........................................................................ 130
6.3.9.3 Autonomous QTouch method hardware resource requirement for UC3L...................................... 130
Table 12 Sleep mode support for Autonomous QTouch ............................................................................. 130
6.3.9.4 Autonomous QTouch Sensor API Flow for UC3L ........................................................................ 131
Figure 44 Autonomous QTouch API Flow diagram.................................................................................... 131
6.3.9.5 Autonomous QTouch method Enable and Disable Sensor for UC3L ............................................ 131
6.3.10 Raw acquisition mode support for UC3L ............................................................................132
Figure 45 Raw acquisition mode API Flow diagram................................................................................... 132
6.3.11 Library Configuration parameters for UC3L ......................................................................133
Table 13 QTouch Library for UC3L Configuration parameters.................................................................. 133
6.3.12 Example projects for QTouch Library for UC3L.................................................................134
6.3.12.1 Example Project usage............................................................................................................... 134
Figure 46 GNU Example project usage with AVR32 Studio ...................................................................... 134
Figure 47 IAR Example project usage with IAR Embedded Workbench for AVR32................................. 134
6.3.12.2 QMatrix Example Project .......................................................................................................... 135
6.3.12.3 QTouch Group A Example Project............................................................................................ 135
6.3.12.4 Autonomous QTouch Example Project ..................................................................................... 135
6.3.13 Code and Data Memory requirements for UC3L ................................................................136
6.3.13.1 QMatrix method memory requirement ...................................................................................... 136
Table 14 Typical Code and Data memory for Standalone QMatrix operation ........................................... 136
6.3.13.2 QTouch Group A/B method memory requirement .................................................................... 136
Table 15 Typical Code and Data memory for Standalone QTouch Group A/B operation .......................... 137
6.3.13.3 Autonomous QTouch memory requirement .............................................................................. 137
Table 16 Minimum Code and Data for Standalone Autonomous QTouch sensor....................................... 137
6.3.14 Public header files of QTouch Library for UC3L................................................................137
6.3.15 Type Definitions and enumerations used in the library.......................................................137
6.3.15.1 Typedefs .................................................................................................................................... 137
6.3.15.1.1 touch_acq_status_t ................................................................................................................. 138
6.3.15.1.2 touch_qt_grp_t ....................................................................................................................... 138
6.3.15.2 Enumerations............................................................................................................................. 138
6.3.15.2.1 touch_ret_t.............................................................................................................................. 139
6.3.15.2.2 touch_lib_state_t .................................................................................................................... 139
6.3.15.2.3 touch_acq_mode_t ................................................................................................................. 140
6.3.15.2.4 sensor_type_t.......................................................................................................................... 140
6.3.15.2.5 aks_group_t............................................................................................................................ 140
6.3.15.2.6 hysteresis_t............................................................................................................................. 140
6.3.15.2.7 recal_threshold_t.................................................................................................................... 141
6.3.15.2.8 resolution_t............................................................................................................................. 141
6.3.15.2.9 at_status_change_t ................................................................................................................. 142
6.3.15.2.10 x_pin_options_t.................................................................................................................... 142
6.3.15.2.11 y_pin_options_t.................................................................................................................... 1426 8207L-AT42-05/12
6.3.15.2.12 qt_pin_options_t................................................................................................................... 142
6.3.15.2.13 general_pin_options_t .......................................................................................................... 142
6.3.16 Data structures....................................................................................................................143
6.3.16.1 sensor_t...................................................................................................................................... 143
6.3.16.2 touch_global_param_t ............................................................................................................... 143
6.3.16.3 touch_filter_data_t..................................................................................................................... 144
6.3.16.4 touch_measure_data_t ............................................................................................................... 144
6.3.16.5 touch_qm_param_t .................................................................................................................... 144
6.3.16.6 touch_at_param_t ...................................................................................................................... 145
6.3.16.7 touch_qt_param_t ...................................................................................................................... 146
6.3.16.8 touch_at_status .......................................................................................................................... 146
6.3.16.9 touch_qm_dma_t ....................................................................................................................... 146
6.3.16.10 touch_qm_pin_t......................................................................................................................... 146
6.3.16.11 touch_at_pin_t ........................................................................................................................... 147
6.3.16.12 touch_qt_pin_t........................................................................................................................... 147
6.3.16.13 touch_qm_reg_t ......................................................................................................................... 148
6.3.16.14 touch_at_reg_t ........................................................................................................................... 149
6.3.16.15 touch_qt_reg_t........................................................................................................................... 149
6.3.16.16 touch_qm_config_t.................................................................................................................... 149
6.3.16.17 touch_at_config_t ...................................................................................................................... 150
6.3.16.18 touch_qt_config_t...................................................................................................................... 151
6.3.16.19 touch_general_config_t.............................................................................................................. 151
6.3.16.20 touch_config_t ........................................................................................................................... 152
6.3.16.21 touch_info_t............................................................................................................................... 152
6.3.17 Public Functions of QTouch Library for UC3L...................................................................152
6.3.17.1 QMatrix API.............................................................................................................................. 152
6.3.17.1.1 touch_qm_sensors_init........................................................................................................... 152
6.3.17.1.2 touch_qm_sensor_config........................................................................................................ 153
6.3.17.1.3 touch_qm_sensor_update_config ........................................................................................... 154
6.3.17.1.4 touch_qm_sensor_get_config................................................................................................. 154
6.3.17.1.5 touch_qm_channel_udpate_burstlen ...................................................................................... 154
6.3.17.1.6 touch_qm_update_global_param............................................................................................ 155
6.3.17.1.7 touch_qm_get_global_param ................................................................................................. 155
6.3.17.1.8 touch_qm_sensors_calibrate................................................................................................... 155
6.3.17.1.9 touch_qm_sensors_start_acquisition...................................................................................... 156
6.3.17.1.10 touch_qm_get_libinfo .......................................................................................................... 156
6.3.17.1.11 touch_qm_sensor_get_delta ................................................................................................. 157
6.3.17.2 QTouch Group A and QTouch Group B API ............................................................................ 157
6.3.17.2.1 touch_qt_sensors_init............................................................................................................. 157
6.3.17.2.2 touch_qt_sensor_config.......................................................................................................... 158
6.3.17.2.3 touch_qt_sensor_update_config ............................................................................................. 158
6.3.17.2.4 touch_qt_sensor_get_config................................................................................................... 159
6.3.17.2.5 touch_qt_update_global_param.............................................................................................. 159
6.3.17.2.6 touch_qt_get_global_param ................................................................................................... 159
6.3.17.2.7 touch_qt_sensors_calibrate..................................................................................................... 160
6.3.17.2.8 touch_qt_sensors_start_acquisition ........................................................................................ 160
6.3.17.2.9 touch_qt _sensor_ disable....................................................................................................... 161
6.3.17.2.10 touch_qt _sensor_ reenable .................................................................................................. 161
6.3.17.2.11 touch_qt_get_libinfo ............................................................................................................ 162
6.3.17.2.12 touch_qt_sensor_get_delta ................................................................................................... 162
6.3.18 Autonomous touch API ........................................................................................................162
6.3.18.1.1 touch_at_sensor_init............................................................................................................... 162
6.3.18.1.2 touch_at_sensor_enable.......................................................................................................... 163
6.3.18.1.3 touch_at_sensor_disable......................................................................................................... 163
6.3.18.1.4 touch_at_sensor_update_config ............................................................................................. 163
6.3.18.1.5 touch_at_sensor_get_config ................................................................................................... 164
6.3.18.1.6 touch_at_get_libinfo............................................................................................................... 164
6.3.18.2 Common API............................................................................................................................. 164
6.3.18.2.1 touch_event_dispatcher.......................................................................................................... 164
6.3.18.2.2 touch_deinit............................................................................................................................ 164
6.3.19 Integrating QTouch libraries for AT32UC3L in your application ......................................165
6.3.20 MISRA Compliance Report of QTouch Library for UC3L ..................................................1657
6.3.21 What is covered ...................................................................................................................165
6.3.22 Target Environment.............................................................................................................165
6.3.23 Deviations from MISRA C Standards..................................................................................165
6.3.24 Known Issues with QTouch Library for UC3L ....................................................................166
6.4 QTOUCH LIBRARY FOR ATTINY20 DEVICE ..................................................................................167
6.4.1 Salient Features of QTouch Library for ATtiny20...............................................................167
6.4.1.1 QTouch method sensor................................................................................................................... 167
6.4.2 Compiler tool chain support for ATtiny20...........................................................................167
Table 17 Compiler tool chains support for ATtiny20 QTouch Library....................................................... 167
6.4.3 Overview of QTouch Library for ATtiny20..........................................................................167
Figure 48 Schematic overview of QTouch on Tiny20................................................................................. 168
6.4.4 API Flow diagram for ATtiny20 ..........................................................................................168
Figure 49 Linker configuration options for Tiny20 ..................................................................................... 168
Figure 50 QTouch method for Tiny20 API Flow diagram .......................................................................... 169
6.4.5 QTouch Library configuration parameters for ATtiny20 ....................................................169
Table 18 QTouch Library for ATtiny20 Configuration parameters............................................................. 170
6.4.6 QTouch Library ATtiny20 Example projects.......................................................................171
6.4.7 QTouch Library ATtiny20 code and data memory requirements ........................................171
Table 19 QTouch Library for ATtiny20 Memory requirements.................................................................. 171
6.5 QTOUCH LIBRARY FOR ATTINY40 DEVICE ..................................................................................172
6.5.1 Salient Features of QTouch Library for ATtiny40...............................................................172
6.5.1.1 QTouch method sensor................................................................................................................... 172
6.5.2 Compiler tool chain support for ATtiny40...........................................................................173
Table 20 Compiler tool chains support for ATtiny40 QTouch Library....................................................... 173
6.5.3 Overview of QTouch Library for ATtiny40..........................................................................173
Figure 51 Schematic overview of QTouch on Tiny40................................................................................. 173
6.5.4 API Flow diagram for ATtiny40 ..........................................................................................174
Figure 52 QTouch method for Tiny40 API Flow diagram .......................................................................... 175
6.5.5 QTouch Library configuration parameters for ATtiny40 ....................................................175
Table 21 QTouch Library for ATtiny40 Configuration parameters............................................................. 176
6.5.6 QTouch Library ATtiny40 Example projects.......................................................................177
6.5.7 QTouch Library ATtiny40 code and data memory requirements ........................................177
Table 22 QTouch Library for ATtiny40 Memory requirements.................................................................. 177
6.5.8 Interrupt Handling in QTouch ADC....................................................................................177
7 GENERIC QTOUCH LIBRARIES FOR 2K DEVICES...............................................................178
7.1 INTRODUCTION.............................................................................................................................178
7.2 DEVICES SUPPORTED ....................................................................................................................178
7.3 SALIENT FEATURES OF QTOUCH LIBRARY FOR 2K DEVICES........................................................178
7.4 LIBRARY VARIANTS .....................................................................................................................178
7.5 QTOUCH API FOR 2K DEVICES AND USAGE.................................................................................178
7.5.1 touch_api_2kdevice.h - public header file ...........................................................................178
7.5.2 Sequence of Operations and Using the API.........................................................................179
7.5.2.1 Channel Numbering ....................................................................................................................... 179
7.5.2.1.1 Channel numbering when routing SNS and SNSK pins to different ports............................... 179
7.5.2.1.2 Channel numbering when routing SNS and SNSK pins to the same port ................................ 180
7.5.2.2 Rules For Configuring SNS and SNSK masks for 2K Devices...................................................... 180
7.5.2.2.1 Configuring SNS and SNSK masks in case of Interport: ......................................................... 180
7.5.2.2.2 Configuring SNS and SNSK masks in case of Intraport: ......................................................... 181
7.5.3 Integrating QTouch libraries for 2K Devices in your application.......................................181
7.6 MISRA COMPLIANCE REPORT.....................................................................................................182
7.6.1 What is covered ...................................................................................................................182
7.6.2 Target Environment.............................................................................................................182
7.6.3 Deviations from MISRA C Standards..................................................................................182
7.6.3.1 QTouch acquisition method libraries for 2K devices..................................................................... 182
8 REVISION HISTORY......................................................................................................................183
DISCLAIMER ...........................................................................................................................................1858 8207L-AT42-05/12
1 Preface
This manual contains information that enables customers to implement capacitive touch solutions
on ATMEL AVR® microcontrollers and ARM®
-based AT91SAM microcontrollers using ATMEL
QTouch libraries. This guide is a functional description of the library software, its programming
interface and it also describes its use on the supported reference systems.
Use of this software is bound by the Software License Agreement included with the Library. This
user guide is applicable for Atmel QTouch® Library 5.0 .
Related documents from ATMEL
Documents related to QTouch capacitive sensing solutions from ATMEL are
• TS2080A/B data sheet.
• QT600 users guide
• Release Notes for ATMEL QTouch libraries.
• A library selection excel workbook that is used for the selection of the appropriate library
variant from the package available under in the install directory. The default location is
C:\Program Files\Atmel\Atmel_QTouch_Libraries_5.x\
• Capacitive touch sensor design guide
http://www.atmel.com/dyn/resources/prod_documents/doc10620.pdf .
If you need Assistance
For assistance with QTouch capacitive sensing software libraries and related issues, contact your
local ATMEL sales representative or send an email to touch@atmel.com for AVR libraries and
at91support@atmel.com for SAM libraries.9
2 Introduction
ATMEL QTouch Library is a royalty free software library (available for GCC and IAR compiler tool
chains) for developing touch applications on standard AVR and SAM microcontrollers. Customers
can link the library into their applications in order to provide touch sensing capability in their
projects. The Library can be used to develop single chip solutions for control applications which
have touch sensing capabilities, or to develop standalone touch sensing solutions which interface
with other host or control devices.
Features of ATMEL QTouch Library include
• Capacitive touch sensing using patented charge-transfer signal acquisition for robust
sensing.
• Support for a wide range of 8- and 32-bit AVRs.
• Support for 32-bit ARM microcontrollers.
• Support for 8-bit tiny AVRs having flash of 2K bytes.
• Support both QTouch and QMatrix acquisition methods and autonomous touch for UC3L.
• Support up to 64 touch sense channels for generic libraries and up to 136 channels for
UC3L libraries.
• Flexible choice of touch sensing functionality (keys, sliders, wheels) in a variety of
combinations.
• Includes Adjacent Key Suppression® (AKS®
) technology for the unambiguous detection of
key events.
• Support for both IAR and GCC compiler tool chains.
• A comparison of various features and parameters between QTouch Libraries for Generic
8-bit and 32-bit AVRs as well as Device Specific Libraries is provided in the table below.
Feature Comparison between Generic QTouch Libraries and Device Specific Libraries
Parameter/Func
tionality
Generic
Libraries,
Tiny_Meg
a_Xmega
Tiny 2K
Libraries
Tiny20
Libraries
Tiny40
Libraries
Generic
Libraries,
32 Bit
AVR
UC3L
Libraries
ATSAM
Libraries
Technology QTouch,
QMatrix
QTouch QTouchADC
QTouchADC
QTouch,
QMatrix
QTouch,
QMatrix
QTouch
Rotors/Sliders
Support
Yes No No No Yes Yes Yes
Filter Callback Yes Yes No Yes Yes Yes Yes
Library Status
Flags
Yes Yes No Yes(Only
Burst Again
Flag)
Yes Yes Yes
Library
Signature
Yes No No No Yes Yes Yes
Calibrate
Sensing
Yes Yes (Only
burst_again
flag)
No Yes Yes Yes Yes
Reset Sensing Yes Yes No Yes Yes Yes Yes
Sensor Deltas Yes Yes No Yes Yes Yes Yes
Maximum AKS
Groups
7 7 1 7 7 7 710 8207L-AT42-05/12
Maximum
Channels, QT
16 4 5 12 32 17 32
Maximum
Rotors/Sliders,
QT
4 0 0 0 8 8
Maximum
Channels, QM
64 0 0 0 64 64 0
Maximum
Rotors/Sliders,
QM
8 0 0 0 8 0
Autonomous
Touch
No No No No No Yes No
Sensor
Reconfiguratio
n
Yes Yes No No Yes Yes Yes
Frequency
Hopping SS
Enabled
Always If
_POWER_
OPTIMIZA
TION = 0
Never Never Always Programma
ble
Always
Delay Cycles
Parameter
QT_DELAY
_CLCYES
(QT
Values: 1 to
255
QM Values:
1,2,3,4,5,10
,25,50)
QT_DELAY
_CLCYES
(Value: 1 to
255)
DEF_CHA
RGE_SHA
RE_DELAY
(Value: 1 to
255)
DEF_QT_C
HARGE_S
HARE_DEL
AY
(Value: 1 to
255)
QT_DELAY
_CYCLES
(QT Values
: 1 to 255
QM Values:
1,2,3,4,5,10
,25,50)
xx_CHLEN,
xx_SELEN
(QT/QM
Value: 3 to
255)
QT_DELAY
_CLCYES
(Value: 3 to
255)
Debug Interface
Enable Macro
_DEBUG_I
NTERFAC
E_
None NDEBUG _DEBUG_
QTOUCH_
STUDIO_
_DEBUG_I
NTERFAC
E_
DEF_TOU
CH_QDEB
UG_ENAB
LE
_DEBUG_I
NTERFAC
E_
This user guide describes the content, design and use of the QTouch Libraries. This should be
read in conjunction with all of the applicable documents listed below
• Device datasheet for the selected ATMEL device used for touch sensing.
• Data sheet for the selected evaluation board.
• A library selection guide that is used for the selection of the appropriate library from the
released package. Default path:
C:\ Program Files\Atmel\Atmel_QTouch_Libaries_5.x\Library_Selection_Guide.xls
The intended readers of this document are engineers, who use the QTouch Library on ATMEL
microcontrollers to realize capacitive touch sensing solutions.
3 Overview
This chapter gives a brief introduction to each of the chapters that make up this document
1. Preface
2. Introduction: Provides an introduction to the scope and use of the QTouch Library.
3. Overview: This chapter
4. Abbreviations and Definitions: Provides a description of the abbreviations and
definitions used in this document
5. Generic QTouch Libraries: Provides an overview of the QTouch libraries and the
different acquisition methods for generic ATMEL devices.
6. Device Specific Libraries: Provides an overview of the QTouch libraries and the
different acquisition methods for ATMEL devices specific for touch sensing.
7. Revision History: Provides a revision history of this document11
4 Abbreviations and Definitions
4.1 Definitions
• AVR: refers to a device(s) in the tinyAVR®, megaAVR®, XMEGA™ and UC3
microcontroller family.
• ARM: refers to a device in the ATSAM ARM® basedmicrocontroller family.
• ATMEL QTouch Library: The combination of libraries for both touch sensing acquisition
methods (QTouch and QMatrix).
• QTouch Technology: A type of capacitive touch sensing technology using self
capacitance - each channel has only one electrode.
• QMatrix Technology: A type of capacitive touch sensing technology using mutual
capacitance – each channel has an drive electrode (X) and an receive electrode (Y).
• Sensor: A channel or group of channels used to form a touch sensor. Sensors are of 3
types (keys, rotors or sliders).
• KEY: a single channel forms a single KEY type sensor, also known as a BUTTON
• ROTOR, also known as a WHEEL, a group of channels forms a ROTOR sensor to detect
angular position of touch.
o A Rotor is composed of 3 channels for a QTouch acquisition method.
o A Rotor can be composed of 3 to 8 channels for QMatrix acquisition method.
• SLIDER, a group of channels forms a SLIDER sensor to detect the linear position of
touch.
o A Slider is composed of 3 channels for a QTouch acquisition method.
o A Slider can be composed of 3 to 8 channels for QMatrix acquisition method.
• AKS: Adjacent Key Suppression. See Section 5.4.5
• SNS PIN: Sense line for capacitive measurement using the QTouch Technology -
connected to Cs.
• SNSK PIN: Sense Key line for capacitive measurement using the QTouch Technology -
connected to channel electrode through Rs.
• X Line: The drive electrode (or drive line) used for QMatrix Technology.
• Y Line: The receive electrode (or receive line) used for QMatrix Technology.
• Port Pair: A combination of SNS port and SNSK port to which sensors are connected for
QTouch technology. The SNS and SNSK ports used in a port pair can be located in the
same AVR Port (8 pins for 4 sensors), or they may be in different 2 different AVR Ports
(8+8 pins for 8 sensors).
• Charge Cycle Period: It is the width of the charging pulse applied to the channel
capacitor.
• Dwell Cycle: In a QMatrix acquisition method, the duration in which charge coupled from
X to Y is captured.
• Acquisition: A single capacitive measurement process.
• Electrode: Electrodes are typically areas of copper on a printed circuit board but can also
be areas of clear conductive indium tin oxide (ITO) on a glass or plastic touch screen.12 8207L-AT42-05/12
• Intra-port: A configuration for QTouch acquisition method libraries, when the sensor SNS
and SNSK pins are available on the same port.
• Inter-port: A configuration for QTouch acquisition method libraries, when the sensor SNS
and SNSK pins are available on distinct ports.
5 Generic QTouch Libraries
5.1 Introduction
ATMEL QTouch provides a simple to use solution to realize touch sensing solutions on a range of
supported ATMEL AVR Microcontrollers. The QTouch libraries provide support for both QTouch
and QMatrix acquisition methods.
Touch sensing using QMatrix or QTouch acquisition methods can be added to an application by
linking the appropriate ATMEL QTouch Library for the AVR Microcontroller and using a simple set
of API to define the touch channels and sensors and then calling the touch sensing API’s
periodically (or based on application needs) to retrieve the channel information and determine
touch sensor states.
Figure 5-1 shows a typical configuration of channels when using an AVR and using the ATMEL
QTouch Library. The ATMEL QTouch Library has been added to a host application running on an
AVR microcontroller. The sample configuration illustrates using the library that supports eight
touch channels numbered 0 to 7. The sensors are configured in the following order,
• Sensor 0 on channels 0 to 2 have been configured as a rotor sensor.
• Sensor 1 on channels 3 to 5 have been configured as a slider sensor.
• Sensor 2 on channel 6 is configured as key sensor.
• Sensor 3 on channel 7 is configured as key sensor.
The host application uses the QTouch Library API’s to configure these channels and sensors,
and to initiate detection of a touch using capacitive measurements.
channel 0
channel 1
channel 2
channel 3
channel 4
channel 5
channel 6
channel 7
Atmel QTouch
Library
Host
Application
sensor0
sensor1
sensor2
sensor3
Figure 5-1 : Typical interface of the ATMEL QTouch library with the host application.
The QTouch libraries use minimal resources of the microcontroller. The sampling of the sensors
is controlled by the QTouch library, while the sampling period is controlled by the application
(possibly using timers, sleep periods, varying the CPU clock, external events like interrupts or
communications, etc).13
5.2 Acquisition Methods
There are two methods available for touch acquisition namely
1. QTouch acquisition method.
2. QMatrix acquisition method.
Libraries for AVR microcontrollers include both acquisition methods. Libraries for ATSAM
microcontrollers include only QTouch acquisition method.
5.2.1 QTouch acquisition method
The QTouch acquisition method charges an electrode of unknown capacitance to a known
potential. The resulting charge is transferred into a measurement capacitor (Cs). The cycle is
repeated until the voltage across Cs reaches a voltage Vih. The signal level is the number of
charge transfer cycles it took to reach that voltage. Placing a finger on the touch surface
introduces external capacitance that increases the amount of charge transferred each cycle,
reducing the total number of cycles required for Cs to reach the voltage. When the signal level
(number of cycles) goes below the present threshold, then the sensor is reported to be in
detected.
QTouch acquisition method sensors can drive single or multiple keys. Where multiple keys are
used, each key can be set for an individual sensitivity level. Keys of different sizes and shapes
can be used to meet both functional and aesthetic requirements.
NOTE: It is recommended to keep the size of the keys larger than 6mmx6mm to ensure reliable
and robust measurements, although actual key design requirements also depend on panel
thickness and material. Refer to the ATMEL Capacitive touch sensor design guide for details.
QTouch acquisition method can be used in two ways
• normal touch contact (i.e. when pressing buttons on a panel), and
• high sensitivity proximity mode (i.e. when a panel lights up before you actually contact it).
Figure 5-2 : QTouch Acquisition
QTouch circuits offers high signal-to-noise ratio, very good low power performance, and the
easiest sensor layout.14 8207L-AT42-05/12
5.2.1.1 Sensor schematics for a QTouch acquisition method design
Electrode
Microcontroller
Used for touch
application
PB1
PC1
SNSK
SNS
Sampling
capacitor
Rs
Cs
Rs- 1k
Cs- 22nF
----------------
Port requirements:
SNS: generic I/O pin
SNSK: generic I/O pin
Rs- Series resistor, Cs – Sample capacitor, PB1- PortB bit1, and PC1- PortC bit1
Typical
values:
Figure 5-3 : Schematics for a QTouch acquisition method design
5.2.2 QMatrix acquisition method
QMatrix devices detect touch using a scanned passive matrix of electrode sets. A single QMatrix
device can drive a large number of keys, enabling a very low cost-per-key to be achieved.
Figure 5-4 : QMatrix Acquisition method15
QMatrix uses a pair of sensing electrodes for each channel. One is an emitting electrode into
which a charge consisting of logic pulses is driven in burst mode. The other is a receive electrode
that couples to the emitter via the overlying panel dielectric. When a finger touches the panel the
field coupling is changed, and touch is detected. The drive electrode (or drive line) used for
QMatrix charge transfer is labeled as the X line. The receiver electrode (or receive line) used for
QMatrix charge transfer is labeled as the Y line.
QMatrix circuits offer good immunity to moisture films, extreme levels of temperature stability,
superb low power characteristics, and small IC package sizes for a given key count.
5.2.3 Sensor schematics for a QMatrix acquisition method design
Atmel MCU
X0
...
Xn
Y0A
...
YmA
...
Y0B
YmB
SMP
Vref
RX0
RXn
RY0
RYm
CS0 CSm
RYB0 RYBm
Sensor
0,0
Sensor
n,0
Sensor
n,m
Sensor
0,m
Sensors,
X,Y
Typical values:
RX: 1k
RY: 1k
CS: 4.7nF
RYB: 470k
----------------------------------
Port-pin count =
n + (2 * m) + 2
n – number of X lines
m – number of Y lines
----------------------------------
Port requirements:
X: Configurable I/O pin
YA:Configurable I/O pin (*)
YB: ADC port (*)
SMP: Configurable I/O pin
Vref: AIN0 (Comparator)
(*): The port I/O pin should
be in consecutive order
Figure 5-5 : Schematics for a QMatrix acquisition method design
5.3 Global settings common to all sensors of a specific
acquisition method
The touch sensing using QTouch library could be fine tuned by using a number of configurable
settings. This section explains the settings that are common to all sensors of a specific acquisition
method like QMatrix or QTouch.16 8207L-AT42-05/12
For example, if recalibration threshold (one of the global settings) of QMatrix acquisition method
is set as 1, all QMatrix sensors will have recalibration threshold of 1.
5.3.1 Recalibration Threshold
Recalibration threshold is the level above which automatic recalibration occurs. Recalibration
threshold is expressed as a percentage of the detection threshold setting. This setting is an
enumerated value and its settings are as follows:
• Setting of 0 = 100% of detect threshold (RECAL_100)
• Setting of 1 = 50% of detect threshold (RECAL_50)
• Setting of 2 = 25% of detect threshold (RECAL_25)
• Setting of 3 = 12.5% of detect threshold (RECAL_12_5)
• Setting of 4 = 6.25% of detect threshold (RECAL_6_25)
However, an absolute value of 4 is the hard limit for this setting. For example, if the detection
threshold is say, 40 and the Recalibration threshold value is set to 4. This implies an absolute
value of 2 (40 * 6.25% = 2.5), but this is hard limited to 4.
Setting Variable name Data
Type
Unit Min Max Typical
Recalibration threshold qt_recal_threshold uint8_t Enum 4 Detect
threshold
1
5.3.2 Detect Integration
The QTouch Library features a detect integration mechanism, which acts to confirm detection in a
robust fashion. The detect integrator (DI) acts as a simple signal filter to suppress false detections
caused by spurious events like electrical noise.
A counter is incremented each time the sensor delta has exceeded its threshold and stayed there
for a specific number of acquisitions, without going below the threshold levels. When this counter
reaches a preset limit (the DI value) the sensor is finally declared to be touched. If on any
acquisition the delta is not seen to exceed the threshold level, the counter is cleared and the
process has to start from the beginning. The DI process is applicable to a ‘release’ (going out of
detect) event as well.
For example, if the DI value is 10, then the device has to exceed its threshold and stay there for
10 acquisitions in succession without going below the threshold level, before the sensor is
declared to be touched.
Setting Variable
name
Data Type Unit Min Max Typical
D
I
qt_
di
uint8_
t
Cycle
s
0 25
5
4
5.3.3 Drift Hold Time
Drift Hold Time (DHT) is used to restrict drift on all sensors while one or more sensors are
activated. It defines the length of time the drift is halted after a key detection.17
This feature is useful in cases of high density keypads where touching a key or floating a finger
over the keypad would cause untouched keys to drift, and therefore create a sensitivity shift, and
ultimately inhibit any touch detection.
Setting Variable name Data Type Unit Min Max Typical
Drift hold time qt_drift_hold_time uint8_t 200 ms 1 255 20 (4s)
5.3.4 Maximum ON Duration
If an object unintentionally contacts a sensor resulting in a touch detection for a prolonged interval
it is usually desirable to recalibrate the sensor in order to restore its function, perhaps after a time
delay of some seconds.
The Maximum on Duration timer monitors such detections; if detection exceeds the timer’s
settings, the sensor is automatically recalibrated. After a recalibration has taken place, the
affected sensor once again functions normally even if it still in contact with the foreign object.
Max on duration can be disabled by setting it to zero (infinite timeout) in which case the channel
never recalibrates during a continuous detection (but the host could still command it).
Setting Variable name Data Type Unit Min Max Typical
Maximum ON Duration qt_max_on_duration uint8_t 200 ms 0 255 30 (6s)
5.3.5 Positive / Negative Drift
Drift in a general sense means adjusting reference level (of a sensor) to allow compensation for
temperature (or other factor) effect on physical sensor characteristics. Decreasing reference level
for such compensation is called Negative drift & increasing reference level is called Positive drift.
Specifically, the drift compensation should be set to compensate faster for increasing signals than
for decreasing signals.
Signals can drift because of changes in physical sensor characteristics over time and
temperature. It is crucial that such drift be compensated for; otherwise false detections and
sensitivity shifts can occur.
Drift compensation occurs only while there is no detection in effect. Once a finger is sensed, the
drift compensation mechanism ceases since the signal is legitimately detecting an object. Drift
compensation works only when the signal in question has not crossed the ‘Detect threshold’ level.
The drift compensation mechanism can be asymmetric; it can be made to occur in one direction
faster than it does in the other simply by changing the appropriate setup parameters.
Signal values of a sensor tend to decrease when an object (touch) is approaching it or a
characteristic change of sensor over time and temperature. Decreasing signals should not be
compensated for quickly, as an approaching finger could be compensated for partially or entirely
before even touching the channel (negative drift).
However, an object over the channel which does not cause detection, and for which the sensor
has already made full allowance (over some period of time), could suddenly be removed leaving
the sensor with an artificially suppressed reference level and thus become insensitive to touch. In
the latter case, the sensor should compensate for the object’s removal by raising the reference
level relatively quickly (positive drift).18 8207L-AT42-05/12
Setting Variable name Data Type Unit Min Max Typical
Negative Drift qt_neg_drift_rate uint8_t 200 ms 1 127 20 (4s)
Positive Drift qt_pos_drift_rate uint8_t 200 ms 1 127 5 (1s)
5.3.6 Positive Recalibration Delay
If any key is found to have a significant drop in signal delta, (on the negative side), it is deemed to
be an error condition. If this condition persists for more than the positive recalibration delay, i.e.,
qt_pos_recal_delay period, then an automatic recalibration is carried out.
A counter is incremented each time the sensor delta is equal to the positive recalibration
threshold and stayed there for a specific number of acquisitions. When this counter reaches a
preset limit (the PRD value) the sensor is finally recalibrated. If on any acquisition the delta is
seen to be greater than the positive recalibration threshold level, the counter is cleared and the
positive drifting is performed.
For example, if the PRD value is 10, then the delta has to drop below the recalibration threshold
and stay there for 10 acquisitions in succession without going below the threshold level, before
the sensor is declared to be recalibrated.
Setting Variable name Data Type Unit Min Max Typical
Positive
Recalibration
Delay
qt_pos_recal_delay uint8_t cycles 1 255 3
5.4 Sensor specific settings
Apart from global settings as mentioned in the section above, touch sensing using QTouch library
could also be fine tuned by more number of configurable settings.
This section explains the settings that are specific to each sensor. For example, sensor 0 can
have a detect threshold (one of the sensor specific setting) that is different from sensor 1.
5.4.1 Detect threshold
A sensor’s negative (detect) threshold defines how much its signal must drop below its reference
level to qualify as a potential touch detect. The final detection confirmation must however satisfy
the Detect Integrator (DI) limit. Larger threshold values desensitize sensors since the signal must
change more (i.e. requires larger touch) in order to exceed the threshold level. Conversely, lower
threshold levels make sensors more sensitive.
Threshold setting depends on the amount of signal swing that occurs when a sensor is touched.
Thicker front panels or smaller electrodes usually have smaller signal swing on touch, thus
require lower threshold levels.
Setting Variable name Data Type Unit Min Max Typical
Threshold threshold uint8_t counts 3 255 10 – 20
5.4.2 Hysteresis
This setting is sensor detection hysteresis value. It is expressed as a percentage of the sensor
detection threshold setting. Once a sensor goes into detect its threshold level is reduced (by the 19
hysteresis value) in order to avoid the sensor dither in and out of detect if the signal level is close
to original threshold level.
• Setting of 0 = 50% of detect threshold value (HYST_50)
• Setting of 1 = 25% of detect threshold value (HYST_25)
• Setting of 2 = 12.5% of detect threshold value (HYST_12_5)
• Setting of 3 = 6.25% of detect threshold value (HYST_6_25)
Setting Variable name Data Type Unit Min Max Typical
Hysteresis detect_hysteresis uint8_t (2 bits) Enum HYST_6_25 HYST_50 HYST_6_25
5.4.3 Position Resolution
The rotor or slider needs the position resolution (angle resolution in case of rotor and linear
resolution in case of slider) to be set. Resolution is the number of bits needed to report the
position of rotor or slider. It can have values from 2bits to 8 bits.
Setting Variable
name
Data
Type
Unit Min Reported
position
Max Reported
position
Typica
l
Position
Resoluti
on
position_
resolution
uint8_t
(3 bits)
- 2 bits 0 – 3 8 bits 0-255 8
5.4.4 Position Hysteresis
In case of QMatrix, the rotor or slider needs the position hysteresis (angle hysteresis in case of
rotor and linear hysteresis in case of slider) to be set. It is the number of positions the user has to
move back, before touch position is reported when the direction of scrolling is changed and
during the first scrolling after the touch down.
Hysteresis can range from 0 (1 position) to 7 ( 8 positions). The hysteresis is carried out at 8 bits
resolution internally and scaled to desired resolution; therefore at resolutions lower than 8 bits
there might be a difference of 1 reported position from the hysteresis setting, depending on where
the touch is detected.
At lower resolutions, where skipping of the reported positions is observed, hysteresis can be set
to 0 (1 position). At Higher resolutions (6 ..8bits) , it would be recommended to have a hysteresis
of at least 2 positions or more.
NOTE:
It is not valid to have a hysteresis value more than the available bit positions in the resolution.
Ex: do not have a hysteresis value of 5 positions with a resolution of 2 bits (4 positions).
Setting Variable name Data Type Unit Min Max Typical
Position
Hysteresis
position_hysteresis uint8_t (3 bits) - 0 7 3
NOTE:
Position hysteresis is not valid (unused) in case of QTouch acquisition method libraries.20 8207L-AT42-05/12
5.4.5 Adjacent Key Suppression (AKS)
In designs where the sensors are close together or set for high sensitivity, multiple sensors might
report detect simultaneously if touch is near them. To allow applications to determine the
intended single touch, the touch library provides the user the ability to configure a certain number
of sensors in an AKS group.
When a group of sensors are in the same AKS group, then only the first strongest sensor will
report detection. The sensor reporting detection will continue to report detection even if another
sensor’s delta becomes stronger. The sensor stays in detect until its delta falls below its detection
threshold, and then if any more sensors in the AKS group are still in detect then the strongest will
report detection. So at any given time only one sensor from each AKS group will be reported to
be in detect.
The library provides the ability to configure any sensor to be included in any one of the Adjacent
Key Suppression Groups (AKS Group).
Setting Variable name Data Type Unit Min Max Typical
AKS Group aks_group uint8_t (3 bits) Enum 0 (off) 7 0 (off)
5.5 Using the Sensors
5.5.1 Avoiding Cross-talk
In ATMEL QTouch library variants that use QTouch acquisition technology, adjacent sensors are
not measured at the same time. This prevents interference due to cross-talk between adjacent
channels, but at the same time some sensor configurations take longer to measure than others.
For example, if an 8-channel device is configured to support 8 keys, then the library will measure
the keys on channels 0, 2, 4, and 6 parallely, followed by keys on channels 1, 3, 5, and 7. If the
same device is configured, say, to support 4 keys, putting them either on all the odd channels or
on all the even channels means that they can all be measured simultaneously.
This means the library calls are faster, and the device can use less power. So, it is recommended
that the appropriate channel numbers are used when using less than the maximum number of
channels available for the device to ensure optimum performance. In a similar sense for faster
execution and reduced power consumption, it is also advisable to use intra-port sensor
configuration instead of inter-port sensor configuration while using 4 channels on the same port.
5.5.2 Multiple measurements
The library will not automatically perform multiple measurements on a sensor (Ex: To resolve for
instance Detect Integration or recalibration.). The user is given the option to perform the
measurement multiple times if certain conditions are met. This will enable the user to implement
the time critical code thereby making the qt_measure_sensors() a non-blocking API .The host
application has to perform multiple measurements, based on the need. The global flag
QTLIB_BURST_AGAIN indicating that multiple measurements are needed is passed to the user.
This is BIT8 of the return value from the qt_measure_sensors( ) API. The main_.c
has the example usage to perform multiple measurements.
If QTLIB_BURST_AGAIN = 1, multiple measurements are needed to
To compensate for drift
Resolve re-calibration
Resolve calibration.
Resolve detect integration.21
If QTLIB_BURST_AGAIN = 0, multiple measurements are not needed and the user can execute
the host application code. Apart from QTLIB_BURST_AGAIN, various flags are provided to the
user to perform the multiple measurements based on the need of the host application to act to
specific situation. Description of the these flags can be found in the section5.6.5.6
Note: To maintain robustness and timing of the touch sensing measurement, it is recommended
that the user calls the qt_measure_sensors() immediately if the flag QT_BURST_AGAIN=1.
However, the user is allowed to run time- critical section (not more than few instructions) of the
host application comprising on the touch sensing timing.
5.5.3 Guard Channel
Guard channel in Qtouch Acquisition Method allows one key to be configured as a guard channel
to help prevent false detection. Guard channel keys should be more sensitive than the other keys
(physically bigger or larger Cs).To enable key as guard channel, the designated key is connected
to a sensor pad which detects the presence of touch and overrides any output from the other
keys using the AKS feature.
The key can be configured to have a guard channel function by adjusting a number of
independent settings. The Guard channel is designed so that it is likely to be activated unless a
key is accurately touched.
The guard channel sensor must be set up so that it is slightly more sensitive than the keys that it
surrounds. The exact amount of increase depends on the application and is best determined by
experimentation.
There are three methods of increasing the sensor sensitivity that can be used in combination:
1. Increasing the size of the sensor.
2. Increasing the value of the Sample Capacitor (Cs).
3. Adjust the detection threshold for the sensor.
The sensor size and capacitor values should be altered to establish the base sensitivity for the
sensor. Once these values have been established, the detection threshold can be used to fine
tune the sensor.
MCU with
SNS and
SNSK
Pins 22 8207L-AT42-05/12
The Above figure illustrates how a Guard sensor/key is to be visualized.It has six keys and five
keys are surrounded by a Guard Channel.
Please refer QTAN0031 for further information on Guard Channel.
http://www.atmel.com/dyn/resources/prod_documents/QTAN0031(2).pdf
5.6 QTouch API and Usage
The Atmel QTouch library provides support for many devices. This chapter explains the touch
library for such devices without any hardware support.
5.6.1 QTouch Library API
This section describes the QTouch library Application Programming Interface (API) for touch
sensing using QTouch and QMatrix acquisition methods.
Using the API, Touch sensors and the associated channels can be defined. Once touch sensing
has been initiated by the user, the host application can use the API to make touch measurements
and determine the status of the sensors.
5.6.2 touch_api.h - public header file
The touch_api.h header file is the public header file which needs to be included in users
application and it has the type definitions and function prototypes of the API’s listed in sections
5.6.3 , 5.6.4 and 5.6.5
The touch_api.h header file is located in the library distribution in the following directory.
• ..\Atmel_QTouch_Libraries_5.x\Generic_QTouch_Libraries\include
5.6.3 Type Definitions and enumerations used in the library
5.6.3.1 Typedefs
This section lists the type definitions used in the library.
Typedef Notes
uint8_t unsigned 8-bit integer
int8_t signed 8-bit integer
uint16_t unsigned 16-bit integer
int16_t signed 16-bit integer
uint32_t unsigned 32-bit integer
threshold_t unsigned 8-bit integer
used for setting a sensor detection threshold
5.6.3.2 Enumerations
This section lists the enumerations used in the QTouch Library.
5.6.3.2.1 sensor_type_t
Enumeration sensor_type_t
Use Define the type of the sensor
Values Comment
SENSOR_TYPE_UNASSIGNED Channel is not assigned to any sensor
SENSOR_TYPE_KEY Sensor is of type KEY
SENSOR_TYPE_ROTOR Sensor is of type ROTOR23
SENSOR_TYPE_SLIDER Sensor is of type SLIDER
5.6.3.2.2 aks_group_t
Enumeration aks_group_t
Use Defines the Adjacent Key Suppression (AKS) groups each sensor may be
associated with ( see section 5.3.4 Maximum ON Duration)
AKS is selectable by the system designer
7 AKS groups are supported by the library
Values Comment
NO_AKS_GROUP NO AKS group selected for the sensor
AKS_GROUP_1 AKS Group number 1
AKS_GROUP_2 AKS Group number 2
AKS_GROUP_3 AKS Group number 3
AKS_GROUP_4 AKS Group number 4
AKS_GROUP_5 AKS Group number 5
AKS_GROUP_6 AKS Group number 6
AKS_GROUP_7 AKS Group number 7
5.6.3.2.3 channel_t
Enumeration channel_t
Use The channel numbers used in the library.
When using the QTouch acquisition method, the channel numbers have a one
to one mapping to the pin numbers of the port being used.
When using the QMatrix acquisition method, the channel numbers are ordered
in a matrix sequence
Values Comment
CHANNEL_0 Channel number : 0
CHANNEL_1 Channel number : 1
CHANNEL_2 Channel number : 2
CHANNEL_3 Channel number : 3
..... Channel number: ..
Upto CHANNEL ( N-1 ) Channel number N-1 : for an N Channel library
The maximum number of channels supported is dependent on the library variant. Possible values
of N are as listed below
Acquisition method Device type Possible values of N
( Maximum number of channels )
QTouch acquisition 8-bit 4,8,16
32-bit 8, 16, 32
QMatrix Acquisition 8-bit 8,16,32,64
5.6.3.2.4 hysteresis_t
Enumeration Hysteresis_t
Use Defines the sensor detection hysteresis value. This is expressed as a
percentage of the sensor detection threshold.
This is configurable per sensor.
HYST_x = hysteresis value is x percent of detection threshold value (rounded 24 8207L-AT42-05/12
down).
Note that a minimum value of 2 is used as a hard limit. Example: if detection
threshold = 20, then:
HYST_50 = 10 (50 percent of 20)
HYST_25 = 5 (25 percent of 20)
HYST_12_5 = 2 (12.5 percent of 20)
HYST_6_25 = 2 (6.25 percent of 20 = 1, but set to the hard limit of 2)
5.6.3.2.5 resolution_t
Enumeration resolution_t
Use For rotors and sliders, the resolution of the reported angle or position.
RES_x_BIT = rotor/slider reports x-bit values.
Example: if slider resolution is RES_7_BIT, then reported positions are in the
range 0…127.
Values Comment
RES_1_BIT 1 bit resolution : reported positions range 0 – 1
RES_2_BIT 2 bit resolution : reported positions range 0 – 3
RES_3_BIT 3 bit resolution : reported positions range 0 – 7
RES_4_BIT 4 bit resolution : reported positions range 0 – 15
RES_5_BIT 5 bit resolution : reported positions range 0 – 31
RES_6_BIT 6 bit resolution : reported positions range 0 – 63
RES_7_BIT 7 bit resolution : reported positions range 0 – 127
RES_8_BIT 8 bit resolution : reported positions range 0 – 255
5.6.3.2.6 recal_threshold_t
Enumeration recal_threshold_t
Use A sensor recalibration threshold. This is expressed as a percentage of the
sensor detection threshold.
This is for automatic recovery from false conditions, such as a calibration while
sensors were touched, or a significant step change in power supply voltage.
If the false condition persists the library will recalibrate according to the settings
of the recalibration threshold.
This setting is applicable to all the configured sensors.
Usage :
RECAL_x = recalibration threshold is x percent of detection threshold value
(rounded down).
Note: a minimum value of 4 is used.
Example: if detection threshold = 40, then:
RECAL_100 = 40 ( 100 percent of 40)
RECAL_50 = 20 ( 50 percent of 40)
RECAL_25 = 10 ( 25 percent of 40)
RECAL_12_5 = 5 ( 12.5 percent of 40)
RECAL_6_25 = 4 ( 6.25 percent of 40 = 2, but value is limited to 4)
Values Comment
Values Comment
HYST_50 50% Hysteresis
HYST_25 25% Hysteresis
HYST_12_5 12.5% Hysteresis
HYST_6_25 6.25% Hysteresis25
RECAL_100 100% recalibration threshold
RECAL_50 50% recalibration threshold
RECAL_25 25% recalibration threshold
RECAL_12_5 12.5% recalibration threshold
RECAL_6_25 6.25% recalibration threshold
5.6.4 Data structures
This section lists the data structures that hold sensor status, settings, and diagnostics information
5.6.4.1 qt_touch_status_t
Structure qt_touch_status_t
Input / Output Output from the Library
Use Holds the status ( On/ Off ) of the sensors and the linear and angular positions
of sliders and rotors respectively
Fields Comment
sensor_states[] For Sensor, the sensor_states. Bit “n” = state of nth sensor :
Bit Value 0 - indicates the sensor is not in detect
Bit Value 1 - indicates the sensor is in detect
rotor_slider_values[] Rotors angles or slider positions if rotors and sliders are used. These
values are valid when sensor states shows that the corresponding rotor or
slider is in detect
The macro that can get the sensor state when the sensor number is provided can be something
as below:
#define GET_SENSOR_STATE(SENSOR_NUMBER)
qt_measure_data.qt_touch_status.sensor_states[(SENSOR_NUMBER/8)] &
(1 << (SENSOR_NUMBER % 8))
The host application can use this macro to act accordingly, the following example shows how to
toggle a IO pin (PD2) based on the sensor0 state.( Set PD2 if sensor0 is in detect, and clear PD2
if sensor0 is not in detect)
Ex: /*Set pin PD2 direction as output*/
DDRD |= (1u << PORTD2);
if (GET_SENSOR_STATE(0) !=0)
{ PORTD |= (1u << PORTD2); /* Set PORTD2 */
}
else {
PORTD &= ~(1u << PORTD2); /* Clear PORTD2 */
}
5.6.4.2 qt_touch_lib_config_data_t
Structure qt_touch_lib_config_data_t
Input / Output Input to the library26 8207L-AT42-05/12
Use Global Configuration data settings for the library.
Fields Type Comment
qt_recal_threshold recal_threshold_t Sensor recalibration threshold. Default: RECAL_50 (recalibration
threshold = 50 percent of detection threshold. Refer to section
5.3.1 Recalibration Threshold more details
qt_di uint8_t Sensor detect integration (DI) limit. Default value: 4. Refer to
section 5.3.2 Detect Integration for more details
qt_drift_hold_time uint8_t Sensor drift hold time in units of 200 ms. Default value: 20 (20 x
200 ms = 4s), that is hold off drifting for 4 seconds after leaving
detect. Refer to section 5.3.3 Drift Hold Time for more details
qt_max_on_duration uint8_t Sensor maximum on duration in units of 200 ms. For example:
150 = recalibrate after 30s (150 x 200 ms). 0 = recalibration
disabled Default value: 0 (recalibration disabled). Refer to
section 5.3.4 Maximum ON Duration for more details.
qt_neg_drift_rate uint8_t Sensor negative drift rate in units of 200 ms. Default value: 20
(20 x 200 ms = 4s per LSB). Refer to section 5.3.5 Positive /
Negative Drift for more details
qt_pos_drift_rate uint8_t Sensor positive drift rate in units of 200 ms. Default value: 5 (5 x
200 ms = 1s per LSB). Refer to section 5.3.5 Positive / Negative
Drift for more details
qt_pos_recal_delay uint8_t Sensor positive recalibration delay. Default: 3. Refer to section
5.3.6 for more details.
The measurement limit for touch sensing using QTouch acquisition method is hard coded as
8192.
The QTouch library exports a variable of this type so that the user can specify the threshold
parameters for the library. The API qt_set_parameters() should be called to apply the parameters
specified.
extern qt_touch_lib_config_data_t qt_config_data;
5.6.4.3 qt_touch_lib_measure_data_t
Structure qt_touch_lib_measure_data_t
Input / Output Output from the library
Use Data structure which holds the sensor and channel states and values.
Fields Type Comment
channel_signals uint16_t The measured signal on each channel.
channel_references uint16_t The reference signal for each channel.
qt_touch_status qt_touch_status_t The state and position of the configured sensors
The QTouch library exports a variable of this type which can be accessed to retrieve the touch
status of all the sensors.
extern qt_touch_lib_measure_data_t qt_measure_data;
5.6.4.4 qt_burst_lengths
Structure qt_burst_lengths
Input / Output Input to the library
Use NOTE: Applicable only to the QMatrix acquisition method libraries
This data structure is used to specify the burst lengths for each of the QMatrix
channels27
Fields Type Comment
qt_burst_lengths[] uint8_t The burst length for each of the QMatrix channel in units of pulses. Default
value: 64 pulses.
These values can be configured for each channel individually.
The signal gain for each sensor is controlled by circuit parameters as well as the burst length.
The burst length is simply the number of times the charge-transfer (‘QT’) process is performed on
a given sensor. Each QT process is simply the pulsing of an X line once, with a corresponding Y
line enabled to capture the resulting charge passed through the sensor’s capacitance Cx.
The QMatrix acquisition method library exports a variable of this type which can be accessed to
set the burst length for each of the QMatrix channels
extern uint8_t qt_burst_lengths[QT_NUM_CHANNELS];
5.6.4.5 tag_sensor_t
Structure tag_sensor_t
Input / Output Output from the library
Use Data structure which holds the internal sensor state variables used by the
library.
Fields Type Comment
State uint8_t internal sensor state
general_counter uint8_t general purpose counter: used for calibration, drifting, etc
ndil_counter uint8_t drift Integration counter
Threshold uint8_t sensor detection threshold. Refer to section 5.4.1 Detect threshold for more
details
type_aks_pos_hyst uint8_t holds information for sensor type, AKS group, positive recalibration flag, and
hysteresis value
Bit fields Use
B1 : B0 Hysteresis. Refer to section 5.4.2 Hysteresis for more
details
B2 positive recalibration flag
B5:B3 AKS group. Refer to section 5.4.5 for more details
B7:B6 sensor type
from_channel uint8_t starting channel number for sensor
to_channel uint8_t ending channel number for sensor
Index uint8_t index for array of rotor/slider values
5.6.4.6 qt_lib_siginfo_t
Structure qt_lib_siginfo_t
Input / Output Output from the library
Use Data structure which holds the information about the library variant and its
version information.
qt_lib_siginfo_t structure definition for a QTouch acquisition method library variant
Fields Type Comment
library_version uint16_t Holds the library version information.
Bit fields Use
B3 : B0 Patch version of the library
B7 : B4 Minor version of the library
B15:B8 Major version of the library28 8207L-AT42-05/12
lib_sig_lword uint16_t Holds the general information about the library
Bit fields Use
B1 : B0 Library Type :
00 : QTouch acquisition method
01 : QMatrix acquisition method
B2 Compiler tool chain used
0 – GCC
1 – IAR
B9 : B3 Maximum number of channels
supported by the library
B10 0 – Library supports only keys
1 – Library supports keys and
rotors
B15 : B11 Maximum number of rotors and
sliders supported by the library
lib_sig_hword uint16_t Reserved
qt_lib_siginfo_t structure definitions for a QMatrix acquisition method library variant
Fields Type Comment
library_version uint16_t Holds the library version information.
Bit fields Use
B3 : B0 Patch version of the library
B7 : B4 Minor version of the library
B15:B8 Major version of the library
lib_sig_lword uint16_t Holds the general information about the library
Bit fields Use
B1 : B0 Library Type :
00 : QTouch acquisition method
01 : QMatrix acquisition method
B2 Compiler tool chain used
0 – GCC
1 – IAR
B9 : B3 Maximum number of channels
supported by the library
B10 0 – Library supports only keys
1 – Library supports keys and
rotors
B15 : B11 Maximum number of rotors and
sliders supported by the library
lib_sig_hword uint16_t Holds information about the X and Y lines for a QMatrix library variant
Bit fields Use
B4 : B0 Number of X Lines
B8 : B5 Number of Y Lines
B9 0
5.6.5 Public Functions
This section lists the public functions available in the QTouch libraries and its usage.
5.6.5.1 qt_set_parameters
This function is used to initialize the global configuration settings in the variable
qt_config_data of the QTouch and QMatrix acquisition method libraries.
void qt_set_parameters ( void )29
Arguments Type Comment
Void - This function will initialize the parameters required by the library to default values .But
the default values can be changed by the user by modifying the global threshold
values as defined in qt_touch_lib_config_data_t . See section 0 for details.
NOTE:
• This function can be called any time to apply the threshold parameters of the library as
specified by modifying the global data structure qt_config_data exported by the library.
5.6.5.2 qt_enable_key
This function is used to configure a channel as a key.
void qt_enable_key (
channel_t channel ,
aks_group_t aks_group ,
threshold_t detect_threshold ,
hysteresis_t detect_hysteresis
)
Arguments Type Comment
Channel channel_t Specifies the channel number to be configured for use as a “key”
aks_group aks_group Specifies the aks group associated with the sensor being configured as
“key”
detect_threshold threshold_t Specifies the detect threshold for the sensor
detect_hysteresis hysteresis_t Specifies the detection hysteresis for the sensor
5.6.5.3 qt_enable_rotor
This function is used to configure a set of channels as a rotor.
void qt_enable_rotor (
channel_t from_channel ,
channel_t to_channel ,
aks_group_t aks_group ,
threshold_t detect_threshold ,
hysterisis_t detect_hysterisis ,
resoulution_t angle_resolution ,
uint8_t angle_hysterisis
)
Arguments Type Comment
from_channel Channel_t Specifies the starting channel number to be configured for use as a “Rotor”
to_channel Channel_t Specifies the end channel number to be configured for use as a “Rotor”
aks_group aks_group Specifies the aks group associated with the sensor being configured as
“ROTOR”
detect_threshold threshold_t Specifies the detect threshold for the sensor
detect_hysterisis hysterisis_t Specifies the detection hysteresis for the sensor
angle_resolution resolution_t Specifies the resolution of the reported angle value
angle_hysterisis uint8_t Specifies the hysteresis of the reported angle value
NOTE:
• A “Rotor” sensor requires contiguous channel numbers.
• The rotor / slider number depends on the order in which the rotor or sliders are enabled.
The first rotor or slider enabled will use “rotor_slider_values[0]”, the second will use
“rotor_slider_values[1]”, and so on. The reported rotor value is valid when the rotor is
reported as being in detect.30 8207L-AT42-05/12
• In case of QMatrix acquisition method library, the from_channel and to_channel can be
between 3 to 8 channel numbers apart (i.e. it can support 3 to 8 channel rotors).
• In case of QTouch acquisition method library, the from_channel and to_channel can be 3
channels apart (i.e. can support only 3 channel rotors).
5.6.5.4 qt_enable_slider
This function is used to configure a set of channels as a rotor.
void qt_enable_slider (
channel_t from_channel ,
channel_t to_channel ,
aks_group_t aks_group ,
threshold_t detect_threshold ,
hysterisis_t detect_hysterisis ,
resolution_t position_resolution ,
uint8_t position_hysteresis
)
Arguments Type Comment
from_channel Channel_t Specifies the starting channel number to be configured for use as a
“Slider”
to_channel Channel_t Specifies the end channel number to be configured for use as a “Slider”
aks_group aks_group Specifies the aks group associated with the sensor being configured as
“Slider”
detect_threshold threshold_t Specifies the detect threshold for the sensor
detect_hysterisis hysterisis_t Specifies the detection hysteresis for the sensor
position_resolution resolution_t Specifies the resolution of the reported position value
position_hysterisis uint8_t Specifies the hysteresis of the reported position value
NOTE:
• A “Slider” sensor requires a contiguous numbers of channels.
• The rotor / slider number depends on the order in which the rotor or sliders are enabled.
The first rotor or slider enabled will use “rotor_slider_values[0]”, the second will use.
“rotor_slider_values[1]”, and so on. The reported rotor value is valid when the slider is
reported as being in detect.
• In case of QMatrix acquisition method library, the from_channel and to_channel can be
between 3 to 8 channels apart (i.e. it can support 3 to 8 channel sliders).
• In case of QTouch acquisition method library, the from_channel and to_channel can be 3
channels apart (i.e. can support only 3 channel sliders).
5.6.5.5 qt_init_sensing
This function is used to initialize the touch sensing for all enabled channels. All required sensors
should be configured before calling this function.
void qt_init_sensing ( void )
Arguments Type Comment
Void - -
NOTE:
• All sensors must be configured (using qt_enable_key, qt_enable_rotor or
qt_enable_slider ) before calling this function.
• This functions initializes all the configured sensors, performs calibration.31
5.6.5.6 qt_measure_sensors
This function performs a capacitive measurement on all enabled sensors. The measured signals
for each sensor are then processed to check for user touches, releases, changes in rotor angle
and changes in slider position.
unit16_t qt_measure_sensors( uint16_t current_time_ms )
Arguments Type Comment
current_time_ms uint16 The current time in milliseconds
Return
Value
Comment
uint16_t Returns the status of the Library as a combination of the following bit fields.
Return value Bit
definition
Comments
QTLIB_NO_ACTIVITY 0x0000 No activity detected on any of the
sensors
QTLIB_IN_DETECT 0x0001 At least one sensor is in detect
QTLIB_STATUS_CHANGE 0x0002 At least one sensor has changed
ON/OFF state since the last call to
qt_measure_sensor()
QTLIB_ROTOR_SLIDER_POS_CHANGE 0x0004 At least one rotor/slider has changed
position since the last call to
qt_measure_sensors()
QTLIB_CHANNEL_REF_CHANGE 0x0008 At least one reference value has
changed since last call to
qt_measure_sensors()
QTLIB_BURST_AGAIN 0x0100 Flag to indicate Multiple measurements
needed.
QTLIB_RESOLVE_CAL 0x0200 Multiple measurements needed to
resolve calibration. Call
qt_measure_sensors( ) once again.
QTLIB_RESOLVE_FILTERIN 0x0400 Multiple measurements needed to
resolve filtering. Call
qt_measure_sensors( ) once again.
QTLIB_RESOLVE_DI 0x0800 Multiple measurements needed to
resolve detect integration. Call
qt_measure_sensors( ) once again.
QTLIB_RESOLVE_POS_RECAL 0x1000 Multiple measurements needed to
resolve positive recalibration. Call
qt_measure_sensors( ) once again.
NOTE:
• All sensors must be configured (using qt_enable_key or qt_enable_rotor or
qt_enable_slider) and initialized by calling qt_init_sensing before calling this function.
5.6.5.7 qt_calibrate_sensing
This function forces a recalibration of all enabled sensors.
void qt_calibrate_sensing( void )
Arguments Type Comment
Void - -32 8207L-AT42-05/12
NOTE:
• Recalibration may be useful if, for example, it is desired to globally recalibrate all sensors
on a change in application operating mode.
• This function must be called only when the sensors have been configured and initialized.
5.6.5.8 qt_reset_sensing
This function disables all sensors and resets all configuration settings (for example, “qt_di”) to
their default values.
void qt_reset_sensing( void )
Arguments Type Comment
Void - -
NOTE:
• This may be useful if it is desired to dynamically reconfigure sensing. After calling this
function, any required sensors must be re-enabled, filter callback needs to be reinitialized,
and “qt_init_sensing()” must be called before “qt_measure_sensors()” is called
again.
• In case of QMatrix, the burst lengths for all channels are set to zero.
5.6.5.9 qt_get_sensor_delta
This function returns the delta value for a given channel.
int16_t qt_get_sensor_delta( uint8_t sensor_number )
Arguments Type Comment
sensor_number unit8_t sensor id for which the delta is required
Return type Comment
int16_t The delta value of the sensor specified
NOTE:
• All sensors must be configured (using qt_enable_key or qt_enable_rotor or
qt_enable_slider) and initialized by calling qt_init_sensing before calling this function.
5.6.5.10 qt_get_library_sig
This function is used to retrieve the library version and signature from the library.
void qt_get_library_sig( qt_lib_siginfo_t *lib_sig_ptr )
Arguments Type Comment
lib_sig_ptr qt_lib_siginfo_t * Pointer to the structure which needs to be
updated with the library signature
information
NOTE:
• The function qt_measure_sensors() should have been called at least once prior to calling
this function. 33
5.6.6 Sequence of Operations and Using the API
Figure 6 illustrates the sequence of operations required to be performed to add touch to an end
application. By using the simple API’s as illustrated in the sequence flowchart, the user can add
touch sensing in his design.
5.6.6.1 Channel Numbering
5.6.6.1.1 Channel numbering when using QTouch acquisition method
QTouch acquisition method libraries require 2 GPIO pins per channel. QTouch libraries can be
configured to use 1 to 16 channels requiring 2 to 32 pins respectively. There are two options
provided for connecting the SNS and SNSK pins.
1. The SNS and SNSK pins are connected to separate ports. ( i.e. Interport)
2. The SNS and SNSK pins are connected to the same port. ( i.e. Intraport)
The following list provides a look at various combinations supported by various 8bit AVR
libraries released for each device.
When pin configurability is not used:
• 4-channel library – supports up to 4 channels using 4 consecutive pins on different SNS
and SNSK ports (or) supports up to 4 channels using 8 consecutive pins on the same
port used for both SNS and SNSK lines. This library requires 1 or 2 ports.
• 8-channel library – supports up to 8 channels using 8 consecutive pins on different SNS
and SNSK ports (or) supports up to 8 channels using 16 pins spread over two ports (SNS
and SNSK are on alternate pins) with SNS1 and SNSK1 pins on the first port and SNS2
and SNSK2 pins on the second port. This library requires 2 ports.
• 12-channel library (available only for 8bit AVR devices) – supports up to 12 channels out
of which, 8 channels with 8 consecutive pins for SNS1 and SNSK1 are available on
different ports and the other 4 channels with 8 consecutive pins available on the same
port for both SNS and SNSK lines. This library requires a total of 3 ports.
• 16-channel library – supports up to 16 channels out of which, 8 channels with 8
consecutive pins for SNS1 and SNSK1 are available on different ports and the other 8
channels with 8 consecutive pins are available on a different pair of SNS2 and SNSK2
ports. This library requires a total of 4 ports.
When pin configurability is used:
• 4-channel library – supports up to 4 channels using any 4 pins on different SNS and
SNSK ports (or) supports up to 4 channels using pins on the same port used for both
SNS and SNSK lines. This library requires 1 or 2 ports.
• 8-channel library – supports up to 8 channels using 8 pins on different SNS and SNSK
ports (or) supports up to 8 channels using pins spread over two ports (SNS and SNSK
are on alternate pins) with SNS1 and SNSK1 pins on the first port and SNS2 and SNSK2
pins on the second port. This library requires 2 ports.
• 12-channel library (available only for 8bit AVR devices) – supports up to 12 channels out
of which, 8 channels with 8 pins for SNS1 and SNSK1 are available on different ports and
the other 4 channels with 8 pins available on the same port for both SNS and SNSK
lines. This library requires a total of 3 ports.
• 16-channel library – supports up to 16 channels out of which, 8 channels with 8 pins for
SNS1 and SNSK1 are available on different ports and the other 8 channels with 8 pins
are available on a different pair of SNS2 and SNSK2 ports. This library requires a total of
4 ports.34 8207L-AT42-05/12
Note:
When a library supports 4 channels using 8 consecutive pins on the same port, the SNS and
SNSK pins are allocated alternately. This is valid for all the libraries mentioned above.
Usage of intraport configuration requires more code memory than the interport configuration.
The values mentioned in the Library_selection_Guide.xls are for interport configurations. The
memory consumption for intra-port will be higher to the values mentioned in the
Library_selection_Guide.xls
The configurations on pin configurability should be used in conjunction with the rules for
assigning the pins that are described in section 5.8.2
For UC3 and ATSAM libraries, an n- channel library supports up to n channels using n
consecutive pins on different SNS and SNSK ports (or) supports up to n/2 channels using (n)
consecutive pins on the same port used for both SNS and SNSK lines. This library requires 1 or 2
UC3 or ATSAM ports. In addition to this, for the ATSAM libraries the pins can be configured on 3
ports based on the configuration selected.
NOTE:
Some of the devices in UC3 family has ports having more than 32 pins or less than 32
pins.In those devices, the mapping is given as below:
GPIO Port0 -> A
GPIO Port1 -> B
GPIO Port2 -> C
GPIO Port3 -> X
Example SNS=A and SNSK=X, So channel 0 will be (SNS0 = GPIO0_Pin0 and SNSK0 =
GPIO3_Pin0 ).
Similarly,Example SNS=X and SNSK=X, So channel 0 will be (SNS0 = GPIO3_Pin0 and SNSK0
= GPIO3_Pin1 ).35
qt_reset_sensing()
qt_enable_xxx()
qt_init_sensing()
qt_set_parameters()
init_timer_isr()
check qt_touch_status
The host application (optionally) calls “qt_reset_sensing( )”
to reset all channels and touch sensing parameters to their
default states. This step is only required if the host wants to
dynamically reconfigure the library at runtime
The host application calls “qt_enable_key( )”, “qt_enable_rotor( )”
and/or “qt_enable_slider()” as required to configure the touch
sensors
The host application qt_set_parameters() to initialize the threshold
parameters for the library. If the user needs to change the thresholds,
edit the global data structure qt_config_data prior to calling this API
The host application periodically calls
“qt_measure_sensors( )” to make capacitive measurements.
check the global status variable “qt_touch_status” to see if any
sensors are in detect, and the angle or position of any enabled
rotors or sliders
The host application initializes the timer module required for
capacitive measurement
The host application calls qt_init_sensing() to calibrate all the
configured channels and prepare the sensors for capacitive
measurement
qt_measure_sensors()
Is
QTLIB_BURST_A
GAIN=1
No
Yes
Time-critical host
application code
Check if multiple measurements are needed or not:
To resolve calibration
To resolve DI
To resolve positive recalibration
To compensate for drift
Non-Time critical host application code
Part of host application
which cannot wait till multiple
measurements are complete (should
be as minimal as possible)
Host application which can be executed after
the completion of multiple measurements
for all the channels
Figure 5-6: Sequence of operations to add Touch capability36 8207L-AT42-05/12
5.6.6.1.1.1 Channel numbering when routing SNS and SNSK pins to different ports
Figure 5-7 illustrates a sample QTouch capacitive sensing solution which uses four ports (two
port pairs ) on a device for routing the SNS and SNSK lines required.
When SNS and SNSK pins are available on different ports, the channel numbering follows the pin
numbering in the ports selected, when pin configurability is not used.
• The channel numbers follow the pin numbers starting with the LSB (pin 0 is channel 0
and pin 7 is channel 7).
• When a library on corresponding device is configured to use more than two ports for SNS
and SNSK pins, the channel numbers in the second set of SNS/SNSK port pair continue
from the preceding pair as illustrated in Figure 5-7(pin 0 of next port pair is channel 8 and
pin 7 of the next port pair is channel 15).
• Support for more than one pair of SNS and SNSK ports are not available for UC3™
devices.
• SNS pins within a single port and SNSK pins within another single port can only be used
as channels for slider/rotor. Slider/Rotor channels cannot share SNS/SNSK pins on
different ports.
• Since the channel numbers are fixed to the pins of the SNS and SNSK ports, if the
design calls for use of a subset of the pins available in the SNS and SNSK ports, the user
has to skip the channel numbers of the unused SNS and SNSK pins.
o For example, on a 8 channel configuration using a single pair of SNS and SNSK
ports, if pin 2 is not used for touch sensing ( on both SNS and SNSK ports),
channel number 2 is unavailable and care should be taken while configuring the
channels and sensors to avoid using this channel.37
channel 0
channel 1
channel 2
channel 3
channel 4
channel 5
channel 6
channel 7
sensor0
sensor1
sensor2
sensor3
Port A
All SNSK pins
terminated
on this port
Pin 0
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Port B
All SNS pins
terminated
on this port
Pin 0
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
channel 0
channel 1
channel 2
channel 3
channel 4
channel 5
channel 6
channel 7
channel 8
channel 9
channel 10
channel 11
channel 12
channel 13
channel 14
channel 15
sensor4
sensor5
sensor6
sensor7
Port C
All SNSK pins
terminated
on this port
Pin 0
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Port D
All SNS pins
terminated
on this port
Pin 0
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
channel 8
channel 9
channel 10
channel 11
channel 12
channel 13
channel 14
channel 15
SNS – SNSK
Port Pair one
SNS – SNSK
Port Pair two
Figure 5-7 : channel numbering for QTouch acquisition method when the SNS and SNSK
pins are connected to different ports.
5.6.6.1.1.2 Channel numbering when routing SNS and SNSK pins to different ports with
pin configurability
When SNS and SNSK pins are available on different ports, the channel numbering
follows the pin numbering in the ports selected based on SNS_array and SNSK_array
bits enabled.The pins which needs to be used for touch should be provided in the Pin
Configurator Wizard in QTouch Studio and the pin configurator Wizard tool will generate
the SNS_array and SNSK_array masks and channel numbering will be based on which
pins are enabled for touch in consecutive way.Below is an example to illustrate the same:
Example: 38 8207L-AT42-05/12
SNS and SNSK pins are configured with few rules keeping in mind as illustrated in
section
Pins A0 ,A1,A4 and A6 of PORT A are SNS pins and pins B2,B3,B5,B7 are SNSK pins of
PORT B.
Channel 0 will be forming a SNS-SNSK pair as A0B2.
Channel 1 will be forming a SNS-SNSK pair as A1B3
Channel 2 will be forming a SNS-SNSK pair as A4B5
Channel 3 will be forming a SNS-SNSK pair as A6B7.
The channel numbering is not dependent on the pin numbering.
5.6.6.1.1.3 Channel numbering when routing SNS and SNSK pins to the same port
When SNS and SNSK pins are connected to the same port, the even pin numbers will be used as
SNS pins and the odd pins will be used as the SNSK pins.
• The number of channels supported will be limited 4 channels for an 8-bit device and 16
channels for a 32-bit device (e.g. UC3).
• For e.g., for a 4 channel configuration where the SNS and SNSK pins are connected to
Port B, the port pins 0&1 are used for channel 0.
• The channel number is derived from the position of the pins used for SNS and SNSK
lines for any channel.
channel number = floor( [SNS(or SNSK) pin number] / 2 )
o For e.g., pins 4 and 5 are connected to a SNS/SNSK pair and the channel number
associated with the SNS/SNSK pin is 2.
channel 0
sensor1
sensor2
Port A
All
SNSK
and
SNS pins
terminated
on the same port
Pin 0
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
SNSK pin
SNS pin
SNSK pin
SNS pin
SNSK pin
SNS pin
SNSK pin
SNS pin
channel 1
channel 2
channel 3
Figure 5-8 : Channel numbering for QTouch acquisition method when the SNS and SNSK
pins are connected to the same port
5.6.6.1.1.4 Channel numbering when routing SNS and SNSK pins to the same port with
pin configurability
When SNS and SNSK pins are connected to the same port, different pins can be used as SNS
and SNSK pins.But SNS and SNSK pins are configured with few rules keeping in mind as
illustrated in section
Example:
Pins A0 ,A3 and A5 of PORT A are SNS pins and pins A2,A4,A7 are SNSK pins of PORT
A.
Channel 0 will be forming a SNS-SNSK pair as A0A2.39
Channel 1 will be forming a SNS-SNSK pair as A3A4
Channel 2 will be forming a SNS-SNSK pair as A5A7.
The channel numbering is not dependent on the pin numbering.
5.6.6.1.2 Channel numbering when using QMatrix acquisition method
Figure 5-9 illustrates a QMatrix capacitive sensing solution which uses 4 X lines and 4 Y lines
thereby providing a 16 channel solution.
Note:
1. All channels selected for a specific rotor or slider should be on a single Y line.
2. The choice of ports for X and Y lines is left to the user to based on the availability of the
pins available in the particular device selected. Please refer to the section 5.8.2 for more
details configuring of touch sensing pins for QMatrix.
The channel numbering for QMatrix configuration follows a matrix pattern with the channel
numbers starting from 0 for the matrix intersection (X0Y0 ) and increasing along the X lines for a
given Y line ( Channel 1 is X1Y0 ) and then moving on to the row number 0 for the next column.
Table 1 lists the possible channel numbers and the associated X/Y line associations for the
different configurations of QMatrix library variants.
A group of channels form a sensor and the sensor numbering is determined by the order in which
the user defines the association of channels and uses them as a sensor.
The channel numbering is fixed for a specific library variant based on the number of X and Y lines
used whereas the sensor numbering is determined at the time of usage based on the order in
which the user defines the association of the channels to create a sensor.
Ch 0
X0
X3
X2
X1
Y0 Y1 Y2 Y3
QMatrix Channels
QMatrix also supports such rotor/slider configuration.
The channels selected for a Rotor / Slider MUST be on a single YA/YB line.
KEY
ROTOR/SLIDER
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Ch 8
Ch 9
Ch 10
Ch 11
Ch 12
Ch 13
Ch 14
Ch 15
Figure 5-9: Channel Numbering for QMatrix acquisition method libraries40 8207L-AT42-05/12
Table 1 : Channel numbers for QMatrix configurations
Line label 4
channel
configur
ation
(4 x 1)
8
channel
configurat
ion
(4 x 2)
16
channel
Configura
tion
(8 x 2)
16
channel
Configura
tion
(4 x 4)
32
channel
configurat
ion
(8 x 4)
56
channel
configurat
ion
(8 x 7)
64
channel
configurat
ion
(8 x 8)
Channel 0 X0Y0 X0Y0 X0Y0 X0Y0 X0Y0 X0Y0 X0Y0
Channel 1 X1Y0 X1Y0 X1Y0 X1Y0 X1Y0 X1Y0 X1Y0
Channel 2 X2Y0 X2Y0 X2Y0 X2Y0 X2Y0 X2Y0 X2Y0
Channel 3 X3Y0 X3Y0 X3Y0 X3Y0 X3Y0 X3Y0 X3Y0
Channel 4 N/A X0Y1 X4Y0 X0Y1 X4Y0 X4Y0 X4Y0
Channel 5 N/A X1Y1 X5Y0 X1Y1 X5Y0 X5Y0 X5Y0
Channel 6 N/A X2Y1 X6Y0 X2Y1 X6Y0 X6Y0 X6Y0
Channel 7 N/A X3Y1 X7Y0 X3Y1 X7Y0 X7Y0 X7Y0
Channel 8 N/A N/A X0Y1 X0Y2 X0Y1 X0Y1 X0Y1
Channel 9 N/A N/A X1Y1 X1Y2 X1Y1 X1Y1 X1Y1
Channel 10 N/A N/A X2Y1 X2Y2 X2Y1 X2Y1 X2Y1
Channel 11 N/A N/A X3Y1 X3Y2 X3Y1 X3Y1 X3Y1
Channel 12 N/A N/A X4Y1 X0Y3 X4Y1 X4Y1 X4Y1
Channel 13 N/A N/A X5Y1 X1Y3 X5Y1 X5Y1 X5Y1
Channel 14 N/A N/A X6Y1 X2Y3 X6Y1 X6Y1 X6Y1
Channel 15 N/A N/A X7Y1 X3Y3 X7Y1 X7Y1 X7Y1
Channel 16 N/A N/A N/A N/A X0Y2 X0Y2 X0Y2
Channel 17 N/A N/A N/A N/A X1Y2 X1Y2 X1Y2
Channel 18 N/A N/A N/A N/A X2Y2 X2Y2 X2Y2
Channel 19 N/A N/A N/A N/A X3Y2 X3Y2 X3Y2
Channel 20 N/A N/A N/A N/A X4Y2 X4Y2 X4Y2
Channel 21 N/A N/A N/A N/A X5Y2 X5Y2 X5Y2
Channel 22 N/A N/A N/A N/A X6Y2 X6Y2 X6Y2
Channel 23 N/A N/A N/A N/A X7Y2 X7Y2 X7Y2
Channel 24 N/A N/A N/A N/A X0Y3 X0Y3 X0Y3
Channel 25 N/A N/A N/A N/A X1Y3 X1Y3 X1Y3
Channel 26 N/A N/A N/A N/A X2Y3 X2Y3 X2Y3
Channel 27 N/A N/A N/A N/A X3Y3 X3Y3 X3Y3
Channel 28 N/A N/A N/A N/A X4Y3 X4Y3 X4Y3
Channel 29 N/A N/A N/A N/A X5Y3 X5Y3 X5Y3
Channel 30 N/A N/A N/A N/A X6Y3 X6Y3 X6Y3
Channel 31 N/A N/A N/A N/A X7Y3 X7Y3 X7Y3
Channel 32 N/A N/A N/A N/A N/A X0Y4 X0Y4
Channel 33 N/A N/A N/A N/A N/A X1Y4 X1Y4
Channel 34 N/A N/A N/A N/A N/A X2Y4 X2Y4
Channel 35 N/A N/A N/A N/A N/A X3Y4 X3Y4
Channel 36 N/A N/A N/A N/A N/A X4Y4 X4Y4
Channel 37 N/A N/A N/A N/A N/A X5Y4 X5Y4
Channel 38 N/A N/A N/A N/A N/A X6Y4 X6Y4
Channel 39 N/A N/A N/A N/A N/A X7Y4 X7Y4
Channel 40 N/A N/A N/A N/A N/A X0Y5 X0Y5
Channel 41 N/A N/A N/A N/A N/A X1Y5 X1Y5
Channel 42 N/A N/A N/A N/A N/A X2Y5 X2Y5
Channel 43 N/A N/A N/A N/A N/A X3Y5 X3Y5
Channel 44 N/A N/A N/A N/A N/A X4Y5 X4Y5
Channel 45 N/A N/A N/A N/A N/A X5Y5 X5Y5
Channel 46 N/A N/A N/A N/A N/A X6Y5 X6Y5
Channel 47 N/A N/A N/A N/A N/A X7Y5 X7Y5
Channel 48 N/A N/A N/A N/A N/A X0Y6 X0Y6
Channel 49 N/A N/A N/A N/A N/A X1Y6 X1Y6
Channel 50 N/A N/A N/A N/A N/A X2Y6 X2Y6
Channel 51 N/A N/A N/A N/A N/A X3Y6 X3Y641
Channel 52 N/A N/A N/A N/A N/A X4Y6 X4Y6
Channel 53 N/A N/A N/A N/A N/A X5Y6 X5Y6
Channel 54 N/A N/A N/A N/A N/A X6Y6 X6Y6
Channel 55 N/A N/A N/A N/A N/A X7Y6 X7Y6
Channel 56 N/A N/A N/A N/A N/A N/A X0Y7
Channel 57 N/A N/A N/A N/A N/A N/A X1Y7
Channel 58 N/A N/A N/A N/A N/A N/A X2Y7
Channel 59 N/A N/A N/A N/A N/A N/A X3Y7
Channel 60 N/A N/A N/A N/A N/A N/A X4Y7
Channel 61 N/A N/A N/A N/A N/A N/A X5Y7
Channel 62 N/A N/A N/A N/A N/A N/A X6Y7
Channel 63 N/A N/A N/A N/A N/A N/A X7Y7
5.6.6.2 Sensor Numbering
The ordering and numbering of sensors is related to the order in which the sensors are enabled.
This is independent of the acquisition method (QMatrix or QTouch acquisition method libraries).
For example, consider this code snippet:
….
/* enable slider */
qt_enable_slider (CHANNEL_0, CHANNEL_2, AKS_GROUP_1, 16,
HYST_6_25, RES_8_BIT, 0);
/* enable rotor */
qt_enable_rotor (CHANNEL_3, CHANNEL_5, AKS_GROUP_1, 16, HYST_6_25,
RES_8_BIT, 0);
/* enable keys */
qt_enable_key (CHANNEL_6, AKS_GROUP_2, 10, HYST_6_25);
qt_enable_key (CHANNEL_7, AKS_GROUP_2, 10, HYST_6_25);
In the case above, the slider on channels 0 to 2 will be sensor 0, the rotor on channels 3-to-5 is
sensor 1 and the keys on channels 6 and 7 are sensor numbers 3 and 4 respectively.
When the touch status is reported or queried, the corresponding sensor positions and status
indicate the touch status. For example, the slider is in detect if “qt_measure_data.
qt_touch_status.sensor_states” bit position 0 is set. Similarly, the rotor on channels 3 to 5 is
sensor 1, and the keys on channels 6 and 7 are sensors 2 and 3 respectively.
However, the code could be re-arranged as follows to give a different sensor numbering.
/* enable rotor */
qt_enable_rotor (CHANNEL_3, CHANNEL_5, NO_AKS_GROUP, 16,
HYST_6_25, RES_8_BIT, 0);
/* enable keys */
qt_enable_key (CHANNEL_6, AKS_GROUP_2, 10, HYST_6_25);
qt_enable_key (CHANNEL_7, AKS_GROUP_2, 10, HYST_6_25);
/* enable slider */
qt_enable_slider (CHANNEL_0, CHANNEL_2, NO_AKS_GROUP, 16,
HYST_6_25, RES_8_BIT, 0);
Now, the rotor is sensor 0, the keys are sensors 1 and 2, and the slider is sensor 3.42 8207L-AT42-05/12
So, the order in which the user enables the sensors is the order in which the sensors are
numbered. Depending on the user requirements, the sensors can be configured in the preferred
order.
NOTE: In case of QMatrix, the channels on the Unused X lines (or) unused Y lines should be
ignored and not to be used as arguments in this API.
Ex: If the host application needs only 24 channels , there are two possible options.
1. In 32 (8x4 configuration), if X6 and X7 are unused, channel6, channel7,
channel14, channel15, channel 22, channel23, channel30, channel 31
cannot be used
2. In 32 (8x4 configuration), if Y3 is unused, channe24, channel25,
channel26, channel27, channel 28, channel29, channel30, channel 31
cannot be used
5.6.6.3 Filtering Signal Measurements
The ATMEL QTouch Library API provides a function pointer called “qt_filter_callback”. The user
can use this hook to apply filter functions to the measured signal values.
If the pointer is non-NULL, the library calls the function after library has made capacitive channel
measurements, but before the library has processed the channel information and determining the
sensor states.
channel 0
channel 1
channel 2
channel 3
channel 4
channel 5
channel 6
channel 7
QTouch/QMatrix Channel Acquisition Method
optional qt_filter_callback() function
channel_signals[]
modified channel_signals[]
post-processing
modified channel_signals[]
qt_touch_status.sensor_states[]
qt_touch_status_rotor_slider_values[]
Figure 5-10 : Block diagram to represent usage of filter callback function
Example: Averaging the Last Four Signal Values
1. Add a static variable in the main module: 43
/* filter for channel signals */
static uint16_t filter[QT_NUM_CHANNELS][4];
2. Add a filter function prototype to the main module:
/* example signal filtering function */
static void filter_data_mean_4( void );
3. When configuring the ATMEL QTouch library, set the callback function pointer:
/* set callback function */
qt_filter_callback = filter_data_mean_4;
4. Add the filter function:
void filter_data_mean_4( void )
{
uint8_t i;
/*
* Shift previously stored channel signal data.
* Store new channel signal data.
* Set library channel signal data = mean of last 4 values.
*/
for( i = 0u; i < QT_NUM_CHANNELS; i++ )
{
filter[i][0] = filter[i][1];
filter[i][1] = filter[i][2];
filter[i][2] = filter[i][3];
filter[i][3] = qt_measure_data.channel_signals[i];
qt_measure_data.channel_signals[i] = ( ( filter[i][0] +
filter[i][1] +
filter[i][2] +
filter[i][3] ) / 4u );
}
}
The signal values processed by the ATMEL QTouch Library are now the mean of the last four
actual signal values.
5.6.6.4 Allocating unused Port Pins for User Application
The GPIO pins within a port that are not used for QTouch or QMatrix acquisition methods can be
used for user application. The usage of pins for QTouch is based on the channels that are being
configured while enabling the sensors (keys/rotors/sliders).
The example below configuring 4 keys, a rotor and a slider shows how the pin configurability is
achieved by configuring the sensor channels. The code snippet configures a specific 10 channels
of a 16 channel library based on the GPIO port pins available for QTouch™.
Port Configuration:
#define SNSK1 C
#define SNS1 D
#define SNSK2 A
#define SNS2 B
Channel/Pin Configuration:
/* enable a key on channel 0 */
qt_enable_key( CHANNEL_0, AKS_GROUP_2, 10u, HYST_6_25 );44 8207L-AT42-05/12
/* enable a slider on channels 2 to 4 */
qt_enable_slider( CHANNEL_2, CHANNEL_4, AKS_GROUP_1, 16u, HYST_6_25,
RES_8_BIT, 0u );
/* enable a key on channel 6 */
qt_enable_key( CHANNEL_6, AKS_GROUP_2, 10u, HYST_6_25 );
/* enable a key on channel 7 */
qt_enable_key( CHANNEL_7, AKS_GROUP_2, 10u, HYST_6_25 );
/* enable a rotor on channels 12 to14 */
qt_enable_rotor( CHANNEL_12, CHANNEL_14, AKS_GROUP_1, 16u,
HYST_6_25, RES_8_BIT, 0u );
/* enable a key on channel 15 */
qt_enable_key( CHANNEL_15, AKS_GROUP_2, 10u, HYST_6_25 );
The channel numbers 0,2,3,4,6,7 are allocated to pins 0,2,3,4,6,7 of (D,C) port pair respectively.
Pins 1 and 5 of ports C and D can be used for user application. Similarly the channel numbers
12,13,14,15 are allocated to pins 4,5,6,7 of (B,A) port pair respectively. Pins 1, 2, 3 and 4 of ports
B and A are again unused by the QTouch library and can be used for user application.
5.6.6.5 Disabling and Enabling of Pull-up for AVR devices
The Pull-up circuit available (in AVR devices) for each GPIO pin has to be disabled before
QTouch acquisition is performed. For tinyAVR and megaAVR devices the Pull-up circuit for all
GPIO port pins are enabled and disabled together. When user needs to configure the pins that
are not used by QTouch library for his application, he may enable the Pull-up circuit after QTouch
measurements are performed and disable them before the touch acquisition starts once again (as
shown in the code snippet below).
/* Disable pull-ups for all pins */
MCUCR |= (1u << PUD); //MCUCR_PUD = 1u;
/* perform QTouch measurements */
qt_measure_sensors ( current_time_ms_touch );
/* Enable pull-ups for all pins */
MCUCR &= ~ (1u << PUD); //MCUCR_PUD = 0u;
For XMEGA devices the Pull-up circuit for each individual GPIO port pins can be configured
individually, by writing to the PINnCTRL register of the ports being used.
5.6.7 Constraints
5.6.7.1 QTouch acquisition method constraints
QTouch acquisition method libraries are available for different port combinations.
Some of the key constraints while configuring the sensors are
• Rotors/sliders have to be connected on three adjacent channels. (e.g. (1,2,3) or (3,4,5)
…) within the same port. Possible combinations are (0,1,2), (1,2,3) for a configuration
which supports 4 channels. Possible combinations (0,1,2), (1,2,3), (2,3,4), (3,4,5), (4,5,6),
(5,6,7) for a configuration which supports 8 channels. 45
• If two port pairs are used for the design, all the channels for a sensor have to be
connected on a single port pair. Combining channels from multiple ports is not possible
when designing sensors. e.g. It is not possible to have a rotor with channel numbers (
7,8,9 ) on a 16 channel library variant which uses two port-pairs.
Note: The above constraints are explained with respect to 8bit AVR. The same could be extended
to 32bit AVR and ATSAM for 32 channel libraries where each port has 32 pins.
5.6.7.2 QMatrix acquisition method constraints
QMatrix acquisition method libraries are available for a set of AVRs The library variants can be
configured to have port and pin assignments for X, Ya, Yb and SMP. Please refer to section 5.8.2
for port-pin configurability.
Some of the key constraints are
• The QMatrix acquisition method libraries internally use TIMER1 for the operation,
TIMER1 will not be available for critical sections of the code where the library is called.
But resources are available to the host application when the normal user’s application is
running.
• In case of XMEGA™ devices, the resources are used internal to the library and hence
cannot be used by the host application
o Timer/Counter 1 on PORTC (TCC1)
o Analog Comparator on PORTA (ACA)
o Event System Channel0 (EVSYS_CH0)
• The sensor channel number and the relation with X and Y lines strictly follows from the
table provided in the section Table 1.
• A rotor /slider sensor can be configured with 3 to 8 channels per rotor or slider depending
on the requirement of the application subject to the total number of channels available in
the library variant selected as listed below.
Number of
channels
X x Y Maximum Channels per ROTOR_SLIDER
4 4 x 1 4
8 4 x 2 4
16 4 x 4 4
16 8 x 2 8
32 8 x 4 8
56 8 x 7 8
64 8 x 8 8
• For example, 16 channel libraries with 4X and 4Y lines supports maximum of 4 channels
per Rotor/Slider. But, a 16 channel with 8X and 2Y lines supports maximum of 8
channels per Rotor/Slider.
• If the lines of the Drive and Receive electrode (X lines or the Y lines) share the same
lines with the JTAG, JTAG needs to be disabled. Please check the data sheet to ensure
that there are no conflicts between the X/Y lines and JTAG lines used for the device.
• YB line for a particular device cannot be changed and it has to be the configured to be
the ADC port of the selected device.
• The AIN0 pin of the device needs to be connected to the GND.
• In case of XMEGA devices, the reference pin for input to analog comparator is Pin7 of
PORTA with all the combinations of libraries supported. Hence, this needs to be
connected to GND
• Proper grounding should be taken care when the controller board and touch sensing
board are different.46 8207L-AT42-05/12
• The channels used for an individual rotor or slider should all be on the same Y line.
• The maximum number of Rotors / Sliders supported by the QMatrix acquisition method
depends on the configuration. Refer to the Library_Selection_Guide.xls for details.
• Vcc should be kept at 4.5V or lower for reliable operation
5.6.7.3 Design Guidelines for QMatrix acquisition method systems
AVR Microcontrollers can use a number of clock sources, ranging from high precision external
crystals to less accurate resonators down to simple external RC circuits. Most AVR devices also
come with integrated RC oscillators. This provides a system clock source without additional cost
or board space. When using internal RC oscillators some considerations need to be taken. The
accuracy i.e. frequency of CMOS RC oscillators will vary slightly from device to device due to
process variance.
QMatrix acquisition method uses an internal timer to measure the discharge time of a capacitor,
and any frequency variation or fluctuation in the RC Oscillator will thus show up as a variance in
the measurement data. The application should for this reason be designed and tuned to allow for
such variance in the internal RC oscillator frequency. For most AVR microcontrollers, the rated
accuracy of the internal RC oscillator is 2%, and to have some headroom and guarantee a robust
and stable system, the designer should aim to follow these design rules:
Reference Value should be in the 150-300 range
Typical delta when touched should be at least 10% of the Reference Value
Recommended threshold should be at least 5% of the reference value and at least 50%
of the typical delta (Higher value gives better robustness)
Hysteresis should be as high as possible in noisy systems (50%)
DI should be set to at least 4
If the design of the system does not comply with the rules above, special attention should be
taken when testing it to make sure that the design meets the desired performance. In systems
with big signal values and small deltas (i.e. less than 10%) it is recommended to either change
component values to conform to the 10% delta rule, or change to a higher precision clock source.
QTouch Studio is the preferred tool when checking and validating any QTouch Designs.
5.6.8 Frequency of operation (Vs) Charge cycle/dwell cycle times:
The library needs different charge / dwell cycles based on the operation and design. The
charge/dwell cycles are determined by the QT_DELAY_CYCLES parameter defined by the user.
The recommended range of charge/dwell cycle times that the user must select based on the
operating clock frequency of the Microcontroller is provided in the table below.
Fine tuning of the QT_DELAY_CYCLES to match the sensor design may be done by monitoring
the reference levels, and finding the charge/dwell time where the reference level has reached
>99% of maximum reference value seen. For QTouch acquisition method, the reference value will
decrease as the QT_DELAY_CYCLES is increased. For QMatrix acquisition method, the
reference value will increase with increase in QT_DELAY_CYCLES. If the cycle time is not
optimum, the design may experience temperature sensitivity.
Possible values:
The following table lists the possible values of QT_DELAY_CYCLES for both QTouch and
QMatrix acquisition method libraries.
Acquisition method Possible values47
QTouch Any value from 1- 255 for 8bit AVR
3,4,5,10,25,50 for UC3 and ATSAM
libraries
QMatrix 1,2,3,4,5,10,25,50
Example:
When operating at 4 MHz, 1~10 cycle charge times are recommended (0.125us to 1.25us).
Table 2 : Frequency of operation
Frequency of
Microcontroller
(MHz))
microcontroller Cycle time
(us)
Suitable Charge Cycle times (or)
Suitable Dwell Cycle times
(us)
1 1 1 to 2 cycles (1us to 2us)
2 0.5 1 to 5 cycles (0.5us to 2.5us)
4 0.25 1 to 10 cycles (0.25us to 2.5us)
8 0.125 1 to 10 cycles (0.125us to 1.25us)
10 0.1 2 to 25 cycles (0.2us to 2.5us)
16 0.0625 2 to 25 cycles (0.125us to 1.5625us)
20 0.05 3 to 50 cycles (0.15us to 2.5us)
48 0.02083 5~50 cycles (0.104us to 1.04us)
>48 <0.02083 5 to < 50 (up to 255 cycles for 8bit AVR)
Note:
• For UC3 and ATSAM devices, 1 & 2 charge cycle delay times are not supported.
If the microcontroller is only used for Touch detection then running at the lowest frequency
possible for the desired touch response may provide the best power and EMC performance. If it
is also used for other functions then running at a higher frequency may be necessary. In some
power critical applications it may be worth switching the frequency on the fly, such as lowering the
frequency during touch detect API instead of using long cycle times, and then switching to a
higher frequency for non-touch code. It is necessary to carefully design timer operation when
change frequencies.
5.6.9 Interrupts
This section illustrates the usage of interrupts during qt_measure_sensors call.
The library disables interrupts for time-critical periods during touch sensing. These periods are
generally only a few cycles long, and so host application interrupts should remain responsive
during touch sensing. However, any interrupt service routines (ISRs) during touch sensing should
be as short as possible to avoid affecting the touch measurements or the application
responsiveness.
Interrupts are disabled once for each signal count/burst pulse and this is typically 65 instruction
cycles when Delay cycles (QT_DELAY_CYCLE=1).
The number of times interrupts are disabled during one measurement will depend on signal count
of a channel as well as the number of channels and port configuration like interport (SNS and
SNSK on different port)/intraport (SNS and SNSK on same port).
Example:
4 channel intraport case:
Channel0 is formed by PA0 and PA1 pin with signal count 300.
Channel1 is formed by PA2 and PA3 pin with signal count 200.
Channel2 is formed by PA4 and PA5 pin with signal count 25048 8207L-AT42-05/12
Channel3 is formed by PA6 and PA7 pin with signal count 150
In the above case, the no of times interrupts disabled will be 300 (maximum signal count) as all
four channels burst together in case of intraport.
4 channel interport case:
Channel0 is formed by PA0 and PB0 pin with signal count 300.
Channel1 is formed by PA1 and PB1 pin with signal count 200.
Channel2 is formed by PA2 and PB2 pin with signal count 250
Channel3 is formed by PA3 and PB3 pin with signal count 150
In the above case, as bursting happens in odd and even pairs, so maximum signal counts in case
of both even and odd channels will be taken. Maximum signal count out of even channels
channel0 and channel2 is 300 and maximum signal count out of odd channels channel1 and
channel3 is 250.So total number of times interrupts disabled will be (300 + 250 = 550).
The recommended maximum ISR execution time is 1msec.If ISR time exceeds 1 ms then it may
result in charge leakage which will further lead to rise in signal value. Noise observed in the signal
value will increase. The 1msec ISR limit applies to the total time spent in an ISR during one
acquisition period, and applies only to QTouch and QMatrix. One acquisition period is the time to
complete one burst sequence. This will be the time required to do the 300 pulses situation in the
first example above. In the second example above the 1msec limitation applies to the 300 and
then the 250 pulses; 1msec of total ISR can occur during the 300 and another 1msec ISR can
occur during the 250. This is all about self discharge happening while doing a burst. In the
example below it would be perfectly OK to have a 1msec ISR happening every 5 msec.
If the ISR load is constant and synced with the acquisition (meaning the ISR takes a constant
amount of time and executes in the same amount of time during each burst sequence), the signal
will not suffer at all since the self discharge will be the same every time the acquisition is run. If
there is a strong variation in the total ISR execution time during acquisition this will appear as
noise in the signal due to the variable self discharge of the sample cap.
The time to execute one measurement will depend on various parameters like sampling
capacitor, operating voltage, and different software parameters like QT_DELAY_CYCLES, CPU
frequency.
For single button with below parameters
Sampling Capacitor = 10 nf
CPU Freq= 4 MHZ
VCC= 5V
QT_DELAY_CYCLES=1
Qtouch takes around 2.6 msec for one channel.
Please note that none of the API functions should be called from a user interrupt.
5.6.10 Integrating QTouch libraries in your application
This section illustrates the key steps required in integrating the QTouch library in your application.
5.6.10.1 Directory structure of the library files
The QTouch library directory structure is as listed below
What Where Comments
Root
installation
Default directory is
C:\Program
Files\Atmel\Atmel_QTouch_Libraries_5.x\Generic_QTouch_Libraries
This is the default
directory path but the user
can install the directory in
desired location.
Header file ..\include touch_api.h is located in
this 49
directory.touch_api_2kdev
ic.h for 2K devices support
is also added in this
directory
Configurati
on and
assembler
routines
for
acquisition
QTouch acquisition
method libraries
8-bit
devices
..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QTouch\co
mmon_files
qt_asm_avr.h
qt_asm_tiny_mega.S
qt_asm_xmega.S
qt_asm_avr_config_2kdev
ice.h
qt_asm_tiny_mega_2kdev
ice.S
UC3 Not needed for UC3 devices
ATSAM Not needed for ATSAM devices
QMatrix acquisition
method libraries
8-bit
devices
..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QMatrix\co
mmon_files
qm_asm_avr.h
qm_asm_tiny_mega.S
qm_asm_m8535_m16.S
qm_asm_xmega.S
qm_asm_tiny_mega_m64
_v3g4_avr51g1.S
UC3 ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries\32bit_AV
R\UC3\QMatrix\common_files
touch_config.h
touch_qm_config32_asse
mbler.h
qm_asm_uc3c_gcc.x
qm_asm_uc3c_iar.s82
Library
files
QTouch acquisition
method libraries
8-bit
devices ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QTouch\lib
rary_files
All libraries ( .r90 for IAR
and .a for GCC) for the
supported 8 bit devices
are in this location.
Also r82 libraries for AVR
32 bit devices are also
here
UC3 ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\32bit_AVR\UC3\QTouch\library_files
ATSAM ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AT91SAM\SAM3\QTouch\library_file
s
..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AT91SAM\SAM4\QTouch\library_file
s
QMatrix acquisition
method libraries
8-bit
devices ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QMatrix\lib
rary_files
UC3 ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries\32bit_AV
R\UC3\QMatrix\library_files
Example
Projects
QTouch acquisition
method libraries
8-bit
devices ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QTouch\ex
ample_projects
All example projects using
the libraries above (IAR
and GCC) for the
supported devices are in 50 8207L-AT42-05/12
UC3 ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\32bit_AVR\UC3\QTouch\example_pr
ojects
this location
ATSAM ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries\AT91SA
M\SAM3\QTouch\example_projects
..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries\AT91SA
M\SAM4\QTouch\example_projects\S
AM4S_XPLAINED_DEMO_APPLICA
TION1
QMatrix acquisition
method libraries
8-bit
devices ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QMatrix\ex
ample_projects
UC3 ..\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries\32bit_AV
R\UC3\QMatrix\example_projects
5.6.10.2 Integrating QTouch acquisition method libraries in your application
The following steps illustrate how to add QTouch acquisition method support in your application.
1) QTouch acquisition method library variants are offered for IAR and AVR Studio/GCC tool
chains. First step is to select the compiler tool chain to be used based on the code and
data memory requirements. The list of supported compiler tool chains can be found in
5.7.1.2.
Use the library selection guide (C:\ Program Files\Atmel\Atmel_QTouch_Libaries_5.x\
Library_Selection_Guide.xls) to select the QTouch acquisition method library variant
required for the device.
a. There are specific library variants distributed for each microcontroller. You would
need the following parameters to identify the right library variant to be used in
your application
i. The microcontroller to be used for the application.
ii. The acquisition method to be used for the application.
iii. The number of channels you need for the application.
iv. Whether Rotor and/or Slider support required in the application.
v. The number of rotors and/or slider needed for the application.
b. There are specific variants of the library which is pre-built with a specific
configuration set supported. Use the library selection guide (C:\ Program
Files\Atmel\ Atmel_QTouch_Libaries_5.x\Library_Selection_Guide.xls) to find the
sample project using the QTouch acquisition method library variant.
2) Define the constants and symbol names required
a. The next step is to define certain constants and symbols required in the host
application files where the touch API is going to be used.
b. The constant/symbol names are as listed in the table below.
c. The constant/symbol definitions can be placed in the touch_config.h file. The
user may modify these defined values based on the requirements.
Table 3 : Constant and symbol name definitions required to use the QTouch acquisition
method libraries
Symbol / Constant name Range of values Comments
_QTOUCH_ This macro has to be defined in
order to use QTouch libraries.51
SNS1 & SNSK1 Refer to library selection guide. To be used if only single
port pair is needed for the
design.
SNS1 – SNSK1
&
SNS2 – SNSK2
Refer to library selection guide. To be used if two port pairs
are needed for the design.
_SNS1_SNSK1_SAME_PORT_ Comment/uncomment define To be enabled if the same
port is used for SNSK1 and
SNS1 pins for QTouch. If
SNSK1 and SNS1 pins are
on different ports then this
definition is not required.
_SNS2_SNSK2_SAME_PORT_ Comment/uncomment define To be enabled if the same
port is used for SNSK2 and
SNS2 pins for QTouch. If
SNSK1 and SNS1 pins are
on different ports then this
definition is not required.
QT_NUM_CHANNELS 4, 8, 12, 16 for tinyAVR,
megaAVR and XMEGA device
libraries and 8, 16, 32 for UC3
device libraries.
_ROTOR_SLIDER_ Rotor / slider can be added to
the design, if this macro is
enabled.
A library with rotor / slider
functionality already
available needs to be
selected if this macro is to
be enabled.
QT_DELAY_CYCLES 1 to 255 Please refer to section
5.6.8.
_POWER_OPTIMIZATION_
(Required only for ATtiny and ATmega
libraries. ATxmega and UC3 libraries by
default optimized for power without any
limitations)
0 or 1 Used to reduce the power
consumed by the library.
When power optimization is
enabled the unused pins,
within a port used for
QTouch, may not be usable
for interrupt driven
applications. Spread
spectrum noise reduction is
also disabled when power
optimization is enabled.
_TOUCH_ARM_ To be defined when using
ATSAM libraries
For ATSAM libraries only.
QTOUCH_STUDIO_MASKS This macro needs to be defined
if QTouch Studio Pin
Configurator Wizard.is used to
generate the SNS and SNSK
masks.
Please refer to section 5.8.1
_STATIC_PORT_PIN_CONF_ This macro needs to be defined
only in case of 4 and 8 channel
libraries with interport
configuration and pin
configurability.
Please refer to section 5.8.1
4) Using QTouch API’s in your application to add touch functionality52 8207L-AT42-05/12
a. The clock, host application and other peripherals needed by the host application
needs to be initialized.
b. In your application, create, initialize and configure the sensors.
i. The APIs of interest are qt_enable_key/rotor/slider().see sections 5.6.5.2,
5.6.5.3 and 5.6.5.4.
c. The channel configuration parameters need to be set by calling the
qt_set_parameters() ( see section 5.6.5.1.
d. Once the sensors are configured, qt_init_sensing() has to be called to trigger the
initialization of the sensors with the configuration defined in steps above.
d. Provide timing for the QTouch libraries to operate. i,e the QTouch libraries do not
use any timer resources of the microcontroller. The Host application has to
provide the required timing and also call the API’s at the appropriate intervals to
perform touch sense detect operations.
NOTE: The ATSAM example applications provided with the libraries illustrate the
usage for the evaluation kits supported by the library. Please refer to the main.c files
for reference.
5) Adding the necessary source files
The following files are to be added along with the touch library and user application
before compilation:
• ATtiny, ATmega devices - touch_api.h, qt_asm_avr.h, touch_config.h and
qt_asm_tiny_mega.S
• ATxmega devices - touch_api.h, qt_asm_avr.h, touch_config.h and
qt_asm_xmega.S
• UC3 devices – touch_api.h
• ATSAM devices - touch_api.h and touch_qt_config.h
6) General application notes
• The clock, host application and other peripherals needed by the host application
needs to be initialized.
• Ensure that there are no conflicts between the resources used by the touch
library and the host application.
• Ensure that the stack size for your application is adjusted to factor in the stack
depth required for the operation of the touch libraries.
5.6.10.2.1 Example for 8bit AVR
The example below will explain in detail the steps to follow for library selection.
Criteria Selection Notes
Microcontroller ATMega1280
IDE and compiler tool chain
used AVR STUDIO® IDE
and GNU compiler
The GCC compiled variant of the libraries for the
device selected needs to be used.
Number of Keys required
for the application
3 Each key requires 1 QTouch acquisition channel
Rotors and sliders required Yes
Number of Rotors and
Sliders required
3 Each rotor / slider will require 3 channels.
Number of Channels
required for the application
( should be the sum of all
channels required for all the
keys ,rotors and sliders
used in the design )
12 3 Keys + ( 3 rotors x 3 channels per rotor/slider )
12 channels
Charge cycle time required
for the design
1 cycle Assuming the device is configured with a clock
frequency of 4Mhz
Number of ports needed 3 ports This is determined based on the number of
channels required and the routing required for the
channels SNS and SNSK pins to the ports
For this design, 24 pins are required and we need 53
3 ports to support the sensors.
Choice of ports available
for the design
SNS/
SNSK
Pair1
ports
SNS1 Port
: A
The choice of ports for the port pairs is limited and
can be found in the section 5.7.1.5
SNSK1 Port
: A
SNS/
SNSK
Pair 2
ports
SNS2 Port
: B
SNSK2 Port
: C
Is there a need for reduced
power consumption (and
reduced execution time)?
_POWER_
OPTIMIZATION_ = 1
Enabling _POWER_OPTIMIZATION_ will lead to
a 40% reduction in power consumed by the
library, but at the expense of reduced external
noise immunity. When power optimization is
enabled, the unused pins within a port used for
QTouch, may not be usable for interrupt driven
applications. This option is available only for
ATtiny and ATmega devices.
SNS1 and SNSK1 pins use
the same port.
_SNS1_SNSK1_SAME
_PORT_
The _SNS1_SNSK1_SAME_PORT_ symbol
needs to be defined as port A is used for both
SNS1 and SNSK1 pins.
Given the above requirements for the applications, the first step is to select the right library
variant required.
Step 1: Selecting the right library variant
Referring to the library selection guide, we see that there are a few variants of libraries supported
for ATmega1280. Since the application requires 12 channels and rotor slider support, one has to
select a library variant which supports at least 12 channels or more along with 3 Rotors/Sliders.
Hence we select the 12 channel library variant for GCC complier which supports the required
number of sensors/channels. This works out to be libavr51g1_12qt_k_3rs.a
Step 2: Defining the constants / symbols in the project space
In the host application file (say main.c), define the following constants and symbols
#define QTOUCH_
#define QT_NUM_CHANNELS 12
#define SNSK1 A
#define SNS1 A
#define SNSK2 B
#define SNS2 C
#define QT_DELAY_CYCLES 1
#define _POWER_OPTIMIZATION_ 1
#define _SNS1_SNSK1_SAME_PORT_
NOTE: The above definitions are available in touch_config.h file. Alternatively, you can
define these in your IDE’s project options or have them defined in a separate header file.
Step 3: Usage of library API’s
Now, you can use the touch API’s to create, initialize and perform touch sensing. Please refer to
the sample applications in section 5.6.11.2 for reference. These sample applications illustrate the
usage of the API’s and the sequence of operation.
Step 4: Adding necessary source files for compilation54 8207L-AT42-05/12
The source files needed for compiling your application along with the touch library are
touch_api.h, touch_config.h and qt_asm_tiny_mega.S.
5.6.10.2.2 Example for ATSAM
The example below will explain in detail the steps to follow for library selection.
Criteria Selection Notes
Microcontroller AT91SAM3S
IDE and compiler tool chain used IAR Workbench and GNU compiler The GCC compiled
variant of the libraries for
the device selected needs
to be used.
Number of Keys required for the
application
3 Each key requires 1
QTouch acquisition
channel
Rotors and sliders required Yes
Number of Rotors and Sliders required 3 Each rotor / slider will
require 3 channels.
Number of Channels required for the
application ( should be the sum of all
channels required for all the keys ,rotors
and sliders used in the design )
12 3 Keys + ( 3 rotors x 3
channels per rotor/slider )
12 channels
Charge cycle time required for the design 5 cycles Assuming the device is
configured with a clock
frequency of 48Mhz
Number of SNS/SNSK port pairs needed 2 pairs This is determined based
on the free PIO of the
board
Choice of ports available for the design SNS/SNSK
Pair1 port
SNS1 Port: A The choice of ports for
the port pairs is limited
and can be found in the
section 5.7.1.5 SNSK1 Port: A
SNS/SNSK
Pair 2 port
SNS2 Port: B
SNSK2 Port: B
Given the above requirements for the applications, the first step is to select the right library
variant required.
Step 1: Selecting the right library variant
Referring to the library selection guide, we see that there are a few variants of libraries supported
for AT91SAM3S. One library is for IAR and the other is for GNU. If we want to use IAR
Workbench, we use the library name: libsam3s-32qt-k-8rs-iar.a.
Step 2: Defining the constants / symbols in the project space
In IAR, change preprocessor options by adding the good defines:
_TOUCH_ARM_
_QTOUCH_
SNS1=B
SNSK1=B
SNS2=A
SNSK2=A
QT_NUM_CHANNELS=32
_ROTOR_SLIDER_
QT_DELAY_CYCLES=1055
_SNS1_SNSK1_SAME_PORT_
_SNS2_SNSK2_SAME_PORT_
Step3: Usage of library API’s
Now, you can use the touch API’s to create, initialize and perform touch sensing.
5.6.10.2.3 Checklist of items for integrating QTouch acquisition method libraries
The following is a checklist of items which needs to be ensured when integrating QTouch
acquisition method libraries
The clock prescaler register (e.g. CLKPR, XDIV) needs to be configured correctly based
on the device selected. Some devices have clock frequency selection based on fuses. It
has to be ensured the fuses are set correctly in such cases.
It is recommended to disable PULL-UP resistor on all port pins used for touch sensing on
the device selected (e.g. PUD bit in MCUCR, SFIOR for a few of the tinyAVR and
megaAVR devices Please refer to the Data sheet of the selected device).
The 16 bit timer in each device has been used for performing touch measurements
periodically. The datasheet for all the devices have to be checked to ensure that the
correct timer peripheral and its registers are used (file: main.c).
The interrupt vector macro may also change from device to device and this needs to be
verified in the datasheet for the device used.
Check if the timer is configured correctly to support the measurement period needed (e.g.
25msec or 50 msec).
The sample applications for the evaluation kits and supported devices illustrate the
proper initialization sequence and usage of the timer resources (file: main.c). Please use
this as a reference for your application design.
The host application must provide the current time to the library. This information is passed to the
library as an argument to the function qt_measure_sensors()”. This is used for time-based library
operations such as drift compensation.
5.6.10.3 Integrating QMatrix acquisition method libraries in your application
5.6.10.3.1 Example for 8bit AVR
Based on the application design needs, the user needs to select the right library variant and the
configuration to be used along with the variant. This section illustrates the steps required to select
the right QMatrix acquisition method library variant and configuration for your application. QMatrix
acquisition method library Variants are offered for IAR and AVR-GCC tool chains. First step is to
select the compiler tool chain for which the libraries are required. The list of supported compiler
tool chains can be found in section 5.7.2.2
There are specific library variants distributed for each microcontroller. For your design, you would
need the following information to select the correct library variant
a. Device to be used for the design
b. The number of touch sensing channels needed by the application – Then identify the
Maximum number of channels required for the design that are supported by the library.
c. Number of X lines to be used in the design
a. The ports on which your design permits to have the X lines
b. The X lines can be spread on a maximum of three ports, the more ports used the
more is the code memory requirement by the library.
d. Number of Y lines to be used in the design
a. The port-pins ports on which your design permits to have the Y lines56 8207L-AT42-05/12
e. Do you need support for Rotors and/or Sliders in your design
a. If yes, how many rotors/sliders would be needed?
b. Based on a) above, identify the maximum number of rotors sliders that the library
supports
f. Which compiler platform you intend to use to integrate the libraries – IAR or AVR -GCC
Follow the steps listed below to arrive at the right library variant
1) Select the device from the list of supported devices listed in 5.7.2.4.1
2) Select the right library variant for the device selected from the selection guide available
in
C:\ Program Files\Atmel\Atmel_QTouch_Libaries_5.x\Library_Selection_Guide.xls
Each variant supports
a. a specific number of channels,
b. Supports a specific configuration of X x Y matrix pins ( eg 4 x 2 for 4 - X pins & 2
- Y pins )
c. has support for Rotor / Slider ( either supported or not )
d. support is available for IAR and/or GCC compiler tool chain
e. support for specific number of rotors sliders.
3) Define the constants and symbol names required
a. The next step is to define certain constants and symbols required in the host
application files where the touch API is going to be used. These values are
derived from the parameters defined in step 2 for your application
b. The constant/symbol names are as listed in the table below
c. The constant/symbol definitions can be placed in any of the following
i. In the user’s ‘C’ file prior to include touch_api.h in the file
ii. Modifying the defines in a touch_config.h available in the project folder57
Table 4 :List of configurable parameters for touch library usage.
Symbol / Constant
name
Range of values Comments
_QMATRIX_ Symbol defined to indicate
QMatrix acquisition method is
required
Define this symbol to indicate QMatrix
acquisition method is required
QT_NUM_CHANNELS The number of channels the
library supports.( Possible
values:4,8,16,32,56,64).
Note: 56 channel for only
ATxmega Devices.
Value should be same as the number of
channels that the library supports
NUM_X_LINES The number of X lines the
library supports.( Possible
values:4,8)
Value should be same as the number of X
lines that the library supports. Refer to
library selection guide
NUM_Y_LINES The number of Y lines the
library supports.( Possible
values:1,2,4,7,8)
Note: 7 Y-lines for only
ATxmega Devices)
Value should be same as the number of Y
lines that the library supports. Refer to
library selection guide
_ROTOR_SLIDER_ Symbol defined if Rotor and/or
slider is required
Needs to be added in case user needs to
configure ROTOR/SLIDER
Needs to be removed for ALL KEYS
configuration
QT_MAX_NUM_ROTO
RS_SLIDERS
Maximum number of
rotors/sliders the library
supports( possible
values:0,2,4,8)
Subject to support for rotors/sliders in the
library selected.
QT_DELAY_CYCLES Possible values
:1,2,3,4,5,10,25,50
Please refer to section 5.6.8
NUM_X_PORTS Number of ports on which the
X lines needs to be spread.
(Possible values 1,2,3)
Maximum number of ports that the X lines
can spread is 3.
Note: Code memory required increases
with the increase in NUM_X_PORTS
PORT_X_1 First IO port for configuring the
X lines.Any IO port available
with the device.
Drive electrode for touch sensing using
QMatrix acquisition
Valid when NUM_X_PORTS =1,2,3
PORT_NUM_1 1 Please donot edit this macro
Valid when NUM_X_PORTS =1,2,3
PORT_X_2 Second IO port for configuring
the X lines. Any IO port
available with the device.
Drive electrode for touch sensing using
QMatrix acquisition
Valid when NUM_X_PORTS =2,3
PORT_NUM_2 2 Please donot edit this macro
Valid when NUM_X_PORTS =2,3
PORT_X_3 Third IO port for configuring
the X lines. Any IO port
available with the device.
Drive electrode for touch sensing using
QMatrix acquisition
Valid when NUM_X_PORTS =3
PORT_NUM_3 3 Please donot edit this macro
Valid when NUM_X_PORTS =3
PORT_YA Any IO port available with the
device.
Receive electrode for touch sensing using
QMatrix acquisition
PORT_YB ADC port available for the
device.
Receive electrode for touch sensing using
QMatrix acquisition
PORT_SMP Any IO port available with the
device.
Port of the Sampling pin for touch sensing
using QMatrix acquisition
SMP_PIN Any IO port available with the
device.
Sampling pin for touch sensing using
QMatrix acquisition
_ATXMEGA_ Symbol defined if an ATxmega
Device is used for QMatrix
sensing technology
Needs to be added if the device to be
supported is ATxmegaxxxx58 8207L-AT42-05/12
SHARED_YAYB Possible values:
0 or 1.
#define SHARED_YAYB 1 in case YA and
YB are on same port else 0.
Once you have selected the right library variant and configuration parameters for the application,
follow the steps outlined below to integrate the library variant in your application.
4) Fill in the arrays x_line_info_t x_line_info[NUM_X_LINES] y_line_info_t
ya_line_info[NUM_Y_LINES] and y_line_info_t yb_line_info[NUM_Y_LINES] using the
pin configuration wizard provided by the QTouch Studio.
5) Copy the library variant that was selected in step one to your project’s working directory
or update your project to point to the library selected.
Include the “touch_api.h” header file and assembler source file from the QTouch library in
your application. The touch_api.h can be found in the release package at C:\Program
Files\Atmel\Atmel_QTouch_Libraries_5.x\ Generic_QTouch_Libraries
\AVR_Tiny_Mega_XMega\QMatrix\common_files. The assembler files mentioned below
could be found at the location C:\Program Files\Atmel\Atmel_QTouch_Libraries_5.x\
Generic_QTouch_Libraries \AVR_Tiny_Mega_XMega\QMatrix\common_ files
a. qm_asm_tiny_mega.S in case of ATtiny and ATmega devices.
b. qm_asm_xmega.S in case of ATxmega devices.
c. qm_asm_m8535_m16.S in case of ATmega8535 and ATmega16 devices.
6) Initialize/create and use the touch api’s in your application
a. In your application, create, initialize and configure the sensors.
a. The APIs of interest are qt_enable_key/rotor/slider().see sections 5.6.5.2,
5.6.5.3 and 5.6.5.4
b. configure the global configuration parameters valid for all the sensors in the
library
c. Provide timing for the QTouch libraries to operate. i,e. the QTouch libraries do
not use any timer resources of the microcontroller. The Host application has to
provide the required timing and also call the API’s at the appropriate intervals to
perform touch sense detect operations
7) General application notes
a. The clock, host application and other peripherals needed by the host application
needs to be initialized.
b. The QMatrix acquisition method libraries internally use TIMER1 for their
operation.
c. Ensure that there are no conflicts between the resources used by the touch
library and the host application
d. Ensure that the stack size is adjusted to factor in the stack depth required for the
operation of the touch libraries.
5.6.10.3.1.1 Example
The example below will explain in detail the steps to follow for library selection.
Criteria Selection Notes
Microcontroller ATTiny88 List of supported devices can be
found at
Library_Selection_Guide.xls
Number of
channels required
for the application
6 number channels available for a
Tiny88 is listed in
Library_Selection_Guide.xls
Number of X lines Based on the number of channels, Since 3 X- lines (6 channels ) are 59
needed since 8 channels is needed, 4 X lines
are supported.
NUM_X_LINES is 4
used, Do not initialize 4th element
in x_line_info[NUM_X_LINES].
Hence channel6, channel7 need
not be used.
Number of Y lines
needed
Based on the number of channels,
since 8 channels is needed, 2 Y lines
are supported
NUM_Y_LINES is 2.
Rotors and sliders
required and
Number of
ROTOR/SLIDERS
Yes
2
Library variants supported for
ATTiny88 is listed in the
Library_Selection_Guide.xls
X_LINES on pins
as below(4-X lines)
X0- B0, X1- D2,X3
– B7, X4 – B5
FILL_OUT_X_LINE_INFO(1,0),
FILL_OUT_X_LINE_INFO(2,2),
FILL_OUT_X_LINE_INFO(1,7),
Main file has to be edited based
on the configuration. Refer to
section 5.8.2.1 . Refer channel
numbering from the
section5.6.6.1.2
Or
This can be filled from the output
of the pin configurator tool in
QTouch Studio. Please refer to
section 5.8.2
Y_LINES on pins
as below (2 YLines)
Y0A- D0, Y0B- C1,
Y1A-D5, Y1B-C4,
FILL_OUT_YA_LINE_INFO(0),
FILL_OUT_YA_LINE_INFO(5),
FILL_OUT_YB_LINE_INFO(1),
FILL_OUT_YB_LINE_INFO(4),
Main file has to be edited based
on the configuration. Refer to
section 5.8.2.1
Or
This can be filled from the output
of the pin configurator tool in
QTouch Studio. Please refer to
section 5.8.2
NUM_X_PORTS 2 Since X lines are spread on a
multiple(2) ports: PORTB, PORTD
Compiler tool chain IAR Supported compiler tool chains
listed in 5.7.2.2
Choice of ports
available for the
design
PORT_X_1 = B
PORT_X_2 = D
Any pins that are not conflicting
with the host application and
follow the configuration supported
by library can be used.
YA Line on PORTD
YB Line on PORTC60 8207L-AT42-05/12
SMP Pin on PORTD pin 7 Or
This can be filled from the output
of the pin configurator tool in
QTouch Studio. Please refer to
section 5.8.2
QT_DELAY_CYCLES of 4
Choice of Shared
Ya and Yb on same
port
SHARED_YAYB This should be defined as 0 if YA
and YB not shared on same port
else 1 if shared on same port.
Given the above requirements for the applications, the first step is to select the right library
variant required.
Step 1:
Select the Device that suits the requirements based on the touch sensing channels needed from
the library selection guide available at C:\ Program Files\Atmel\ Atmel_QTouch_Libaries_5.x\
Library_Selection_Guide.xls
Step 2:
From the Library_selection_Guide.xls list,, we see that there are a few variants of libraries
supported for AT Tiny device. Since the application requires 6 channels and rotor slider support,
one has to select a library variant which supports at least 6 channels or more. Hence we select
the 8 channel library which supports the required Port combination and the delay cycle preferred
which works out to be the variant
• libv1g1s1_8qm_4x_2y_krs_2rs.r90
Step 3:
Defining the constants / symbols in the project space or modifying in touch_config.h
In the host application file (say main.c), define the following constants and symbols
#define _QMATRIX_
#define QT_NUM_CHANNELS 8
#define NUM_X_LINES 4
#define NUM_Y_LINES 2
#define NUM_X_PORTS 2
#define PORT_X_1 B
#define PORT_NUM_1 1
#define PORT_X_2 D
#define PORT_NUM_2 2
#define PORT_YA D
#define PORT_YB C
#define PORT_SMP D
#define SMP_PIN 7
#define QT_DELAY_CYCLES 4
#define ROTOR_SLIDER_
#define QT_MAX_NUM_ROTORS_SLIDERS 2
#define SHARED_YAYB 0
NOTE: The above definitions are available in touch_config.h file. Alternatively, you can
define these in your IDE’s project options or have them defined in a separate header file.
Note:
1. Some of these macro’s can be taken from the output of the Pin configurator tool from
QTouch Studio. Refer to section 5.8.261
2. These can also be modified in the touch_config.h, after defining the _QMATRIX_ in the
project space.
3. In case XMEGA device is used for QMatrix the symbol __ATXMEGA_ has to be included
in the Project space along with the symbols mentioned above.
Step 4:
Filling Arrays in the main.c file
According to the pin availability for the touch sensing, initialize the arrays in the main.c file as
below:
x_line_info_t x_line_info[NUM_X_LINES]= {
FILL_OUT_X_LINE_INFO( 1,0u ),
FILL_OUT_X_LINE_INFO( 2,2u ),
FILL_OUT_X_LINE_INFO( 1,7u ),
};
y_line_info_t ya_line_info[NUM_Y_LINES]= {
FILL_OUT_YA_LINE_INFO( 0u ),
FILL_OUT_YA_LINE_INFO( 5u ),
};
y_line_info_t yb_line_info[NUM_Y_LINES]= {
FILL_OUT_YB_LINE_INFO( 0u ),
FILL_OUT_YB_LINE_INFO( 5u ),
};
Note:
1. This part of the snippet can be taken from the output of the Pin configurator tool from
QTouch Studio.
Step 5:
Usage of libraries
Now, you can use the touch API’s to create, initialize and perform touch sensing. Please refer to
the sample applications in section 5.6.11.3 for reference. These sample applications illustrate the
usage of the API’s and the sequence of operation
5.6.10.3.1.2 Resources used by QMatrix acquisition method libraries
The following additional resources are used by the QMatrix acquisition method libraries.
• One Analog Comparator
• One internal Timer ( Usually Timer1 depending on the availability on particular
microcontroller)
• One ADC Multiplexer( The critical section of the touch sensing library disables the use of
ADC as conversion unit and enables the same ADC as a multiplexer, but the user can
use the ADC for conversion in rest of his application code )
• The ADCMUX is used by the library during the touch sensing acquisition, however it is
restored with the value from host application before exiting the qt_measure_sensors().
Such that the ADC is available to the host application for conversion.
In case of XMega devices, the resources are used internal to the library and hence cannot be
used by the host application62 8207L-AT42-05/12
o Analog Comparator0 on PORTA (AC0 on PORTA)
o Timer/Counter1 on PORTC (TCC1)
o Event System Channel0 (EVSYS_CH0)
5.6.10.3.2 Example for 32bit AVR
Based on the application design, the user needs to select the right library variant and the
configuration to be used along with the variant. This section illustrates the steps required to select
the right QMatrix acquisition method library variant and configuration for your application.
For your design, you would need the following information to select the correct library variant
a. Device to be used for the design(only AT32UC3C0512 supported)
b. The number of touch sensing channels needed by the application – Then identify the
Maximum number of channels required for the design that are supported by the library.
c. Number of X lines to be used in the design
a. The port on which your design permits to have the X lines
b. The X lines can be spread on a single port.
d. Number of Y lines to be used in the design
c. The port-pins ports on which your design permits to have the Y lines
e. Do you need support for Rotors and/or Sliders in your design
d. If yes, how many rotors/sliders would be needed?
e. Based on a) above, identify the maximum number of rotors sliders that the library
supports
f. Which compiler platform you intend to use to integrate the libraries – IAR or AVR -GCC
After selecting the right library variant, following steps are to be performed
1) Define the constants and symbol names required
a. The next step is to define certain constants and symbols required in the host
application files where the touch API is going to be used. These values are
derived from the parameters defined in step 2 for your application
b. The constant/symbol names are as listed in the table below
c. The constant/symbol definitions can be placed in any of the following
iii. In the user’s ‘C’ file prior to include touch_api.h in the file
iv. Defined user’s project options.
v. Modify the defines in a touch_config.h
Symbol / Constant
name
Range of values Comments
_QMATRIX_ Symbol defined to indicate
QMatrix acquisition method
is required
Define this symbol to indicate QMatrix
acquisition method is required
QT_NUM_CHANNEL
S
The number of channels
the library supports.(
Possible
values:4,8,16,24,32,64).
Value should be same as the number
of channels that the library supports
NUM_X_LINES The number of X lines the
library supports.( Possible
values:4,8)
Value should be same as the number
of X lines that the library supports.
Refer to library selection guide
NUM_Y_LINES The number of Y lines the
library supports.( Possible
values:1,2,3,4,8)
Value should be same as the number
of Y lines that the library supports.
Refer to library selection guide
_ROTOR_SLIDER_ Symbol defined if Rotor Needs to be added in case user 63
and/or slider is required needs to configure ROTOR/SLIDER
Needs to be removed for ALL KEYS
configuration
QT_MAX_NUM_ROT
ORS_SLIDERS
Maximum number of
rotors/sliders the library
supports( possible
values:0,2,3,4,8)
Subject to support for rotors/sliders in
the library selected.
QT_DELAY_CYCLES Possible values
:1,2,3,4,5,10,25,50
Please refer to section 5.6.8
PORT_X_1 First IO port for configuring
the X lines.Any IO port
available with the device.
Drive electrode for touch sensing
using QMatrix acquisition
PORT_YA Any IO port available with
the device.
Receive electrode for touch sensing
using QMatrix acquisition
PORT_YB Analog Comparator port
available for the device.
Receive electrode for touch sensing
using QMatrix acquisition
PORT_SMP Any IO port available with
the device.
Port of the Sampling pin for touch
sensing using QMatrix acquisition
SMP_PIN Any IO port available with
the device.
Sampling pin for touch sensing using
QMatrix acquisition
Once you have selected the right library variant and configuration parameters for the application,
follow the steps outlined below to integrate the library variant in your application.
1) Fill in the arrays x_line_info_t x_line_info[NUM_X_LINES] y_line_info_t
ya_line_info[NUM_Y_LINES] and y_line_info_t yb_line_info[NUM_Y_LINES] as given in
main.c file.
Filling Arrays in the main.c file
According to the pin availability for the touch sensing, initialize the arrays in the main.c
file as below:
x_line_info_t x_line_info[NUM_X_LINES]= {
FILL_OUT_X_LINE_INFO( 1,0u ),
FILL_OUT_X_LINE_INFO( 1,2u ),
FILL_OUT_X_LINE_INFO( 1,7u ),
FILL_OUT_X_LINE_INFO( 1,15u ),
};
First argument of FILL_OUT_X_LINE_INFO should always be 1 as X port is only on one
port.Second arguments denotes the pins on that particular port.
y_line_info_t ya_line_info[NUM_Y_LINES]= {
FILL_OUT_YA_LINE_INFO( 0u ),
FILL_OUT_YA_LINE_INFO( 5u ),
};
y_line_info_t yb_line_info[NUM_Y_LINES]= {
FILL_OUT_YB_LINE_INFO( 7u ),
FILL_OUT_YB_LINE_INFO( 22u ),
};
Yb lines are one of the inputs of the Analog Comparators. 64 8207L-AT42-05/12
2) Copy the library variant that was selected in step 1 to your project’s working directory or
update your project to point to the library selected.
Include the “touch_api.h” header file and assembler source file from the QTouch library in
your application. The touch_api.h can be found in the release package at C:\Program
Files\Atmel\Atmel_QTouch_Libraries_5.x\Generic_QTouch_Libraries\include. The
assembler files mentioned below could be found at the location C:\Program
Files\Atmel\Atmel_QTouch_Libraries_5.x\Generic_QTouch_Libraries\32bit_AVR\UC3\Q
Matrix\common_files
e. qm_asm_uc3c_gcc.x in case of GCC compiler
f. qm_asm_uc3c_iar.s82 in case of IAR compiler.
3) Initialize/create and use the touch api’s in your application
d. In your application, create, initialize and configure the sensors.
a. The APIs of interest are qt_enable_key/rotor/slider().see sections 5.6.5.2,
5.6.5.3 and 5.6.5.4
e. configure the global configuration parameters valid for all the sensors in the
library
f. Provide timing for the QTouch libraries to operate. i,e. the QTouch libraries do
not use any timer resources of the microcontroller. The Host application has to
provide the required timing and also call the API’s at the appropriate intervals to
perform touch sense detect operations
4) General application notes
g. The clock, host application and other peripherals needed by the host application
needs to be initialized.
h. The QMatrix acquisition method libraries for 32 Bit devices internally use TIMER0
with channel0 for their operation.
i. Ensure that there are no conflicts between the resources used by the touch
library and the host application
5.6.10.3.2.1 Resources used by QMatrix acquisition method libraries for 32 Bit device
Devices supported by 32 Bit Qmatrix Acquisition libraries are:
1. AT32UC3C0512
The following additional resources are used by the QMatrix acquisition method libraries.
• Four Analog Comparator
• One internal Timer ( Timer0 with channel0 )
• Two Analog Comparator Interface ACIFA0/1.
• Event System Channel 16 is used.
The device has two Analog comparator interfaces ACIFA0 and ACIFA1 .Each interface
provides the flexibility to configure two analog comparators ACA and ACB comparators..UC3C
has Four Comparators (AC0A , AC1A , AC0B , AC1B), So there are 10 Possible Yb lines as
given in table below.
User has flexibility to configure maximum 8 Yb lines for maximum 64 channel libraries.Below
table states the Yblines which can be configured
Yb LInes of the Four Port A 65
Analog Comparators Pins
AC0AN0(AC0A Comparator) PA22
AC0AN1(AC0A Comparator) PA27
AC0BP0(AC0A Comparator) PA23
AC1AN0(AC1A Comparator) PA13
AC1AN1(AC1A Comparator) PA07
AC1BP0(AC1A Comparator) PA14
AC0BN0(AC0B Comparator) PA21
AC0BN1(AC0B Comparator) PA29
AC1BN0(AC1B Comparator) PA15
AC1BN1(AC1B Comparator) PA09
These Yb lines are the negative input pins of the analog comparator.To use the library, the below
table shows the lines which are externally grounded for Proper Qmatrix operation
Positive Input Pins of the Four
Analog Comparators
Port A
Pins
AC0AP0(AC0A Comparator) PA20
AC0BP1(AC0B Comparator) PA28
AC1AP0(AC1A Comparator) PA12
AC1BP1(AC1B Comparator) PA08
If only one comparator is used , then the corresponding pin of that comparator is properly
externally grounded.Above table shows the Analog comparator usage and the corresponding
lines which needs to be grounded.
The Port pin configurability is provided in the library to select any port for Ya or X lines.The
Port for Yb lines is fixed which is PORTA as these lines are inputs of the Analog comparators
which are fixed pins of PORTA.
X,YA,YB,SMP
Configurations
Ports on UC3C
PORTA PORTB PORTC PORTD
X Yes Yes Yes Yes
YA Yes Yes Yes Yes
YB Yes(only few
pins of PortA
can be
configured as
Yb Lines)
No No No
SMP Yes Yes Yes Yes66 8207L-AT42-05/12
The configurability is provided to select X,SMP and YA lines on Same Port ,X,SMP and
YB lines on same port.
Number of X ports should be 1 means the X lines should be connected to a single port.
Note: YA and YB cannot be on the same port.
SMP Pin should be less than equal to 19th pin of any Port.
5.6.10.3.3 Checklist of items for integrating QMatrix Capacitive sensing libraries
When integrating QMatrix acquisition method libraries, ensure the following
Check that the CLKPR register is available for the selected device. If not remove the
CLKPR statements.
Ensure that the configuration for the QMatrix is done in touch_config.h and the arrays of
the x_line_info and y_line info are filled as indicated section 5.8.2
MCUCR register is available and if so disable pullups
Check if the timer registers and bit fields used are correct and change them if necessary.
The above settings can be modified by the user by changing the API’s that are available
to the user. The API’s include
o qt_set_parameters ( )
The host application must provide the current time.
This information is passed to the library as an argument to the function
qt_measure_sensors()”. This is used for time-based library operations such as drift
compensation.
The GPIO internal pull-ups must be disabled for all port pins used for touch sensing when
calling the library.
For 8-bit AVR devices, this can be done by
b. Setting the “PUD” bit in the “MCUCR” register or
c. Setting the “PUD” bit in the “SFIOR” register.
• Setting the JTD bit in the “MCUCR” register to disable JTAG Interface in MCU ( if
available ). This can be done only when the JTAG lines are in conflict with the desired
touch sensing lines.
• The library must be called often enough to provide a reasonable response time to user
touches. The typical time to call the library is from 25 ms to 50 ms.
• Care should be taken while using the ADC conversion logic and QMatrix library such that
the host application waits for approximately 1msec before actually calling the
qt_measure_sensors() API depending upon the ADC clock.
5.6.10.4 Common checklist items
5.6.10.4.1 Configuring the stack size for the application
The stack requirements for the QTouch library should be accounted for and the stack size
adjusted in the user’s project for proper operation of the software when using the IAR IDE. This
section lists the stack usage for the different variants of the QTouch and QMatrix acquisition
method libraries applicable to the IAR compiler tool chain.
Note: When using the IAR IDE / compiler tool chain, the map file generated for the application will
list total CSTACK & RSTACK requirements. Please adjust the total CSTACK and RSTACK
values in the IAR project options to be greater than the values listed in the map file. Refer to
section 5.6.11.4 which illustrates how to change the settings in IAR IDE.
Table 5 : Stack requirements of the QTouch capacitive sensing libraries when using IAR IDE
projects67
QTouch Acquisition method Libraries : Stack usage for IAR compiler tool chain
Configuration CSTACK size RSTACK size
Single port pair - only keys ( 4 / 8 channels ) 0x30 0x28
Single port pair – keys/ rotors/ sliders (4/8 channel) 0x40 0x2C
Two port pairs - only keys keys (16 channel) 0x50 0x28
Two port pairs – keys/ rotors/ sliders (16 channel) 0x60 0x2C
Table 6 : Stack requirements of the QMatrix capacitive sensing libraries when using IAR IDE
projects
QMatrix Acquisition method Libraries : Stack usage for IAR compiler tool chain
Number of
channels
Configuration CSTACK size RSTACK size
4 ONLY KEYS 0x20 0x20
4 KEYS/ROTOR/SLIDER 0x30 0x20
8 ONLY KEYS 0x25 0x20
8 KEYS/ROTOR/SLIDER 0x35 0x20
16 ONLY KEYS 0x30 0x20
16 KEYS/ROTOR/SLIDER 0x40 0x20
32 ONLY KEYS 0x35 0x25
32 KEYS/ROTOR/SLIDER 0x45 0x25
56 ONLY KEYS 0x45 0x25
56 KEYS/ROTOR/SLIDER 0x55 0x25
64 ONLY KEYS 0x45 0x25
64 KEYS/ROTOR/SLIDER 0x55 0x25
5.6.11 Example project files
The QTouch library is shipped with various example projects to illustrate the usage of the touch
API’s to add touch sensing to an application across various devices
Sample applications are also provided for the following kits
1 TS2080A, QT600_ATtiny88_QT8, QT600_ATxmega128a1_QT16 : QTouch Technology
evaluation Kits
2 TS2080B, QT600_ATmega324_QM64 : QMatrix Technology evaluation Kits
Note: Example projects must be built in the installed folder, and if moved/copied elsewhere then
paths must be edited appropriately.68 8207L-AT42-05/12
5.6.11.1 Using the Sample projects
The sample applications are shipped with the complete set of files required to configure, build and
download the application for both IAR-workbench and AVR Studio IDE.
Since more than one device may use the same library (applicable for QTouch acquisition method
libraries), example project files and applications have been provided only for select devices which
use these libraries.
5.6.11.2 Example applications for QTouch acquisition method libraries
5.6.11.2.1 Selecting the right configuration
Each example project for a device can support multiple configurations (i.e a. keys only, b. with
rotors and sliders c.16 channel etc…). The configuration sets determine the configuration options
for using the library and also the right library variant to link with the project.
The configuration sets for IAR IDE are named according to the convention listed below
Configuration set for IAR IDE
Naming convention : g_qt_k_rs
Field
Name
Values Comments
vP v1, v3, xmega, uc3a,
uc3b, uc3c
VersionP of the core AVR device supported by this library variant
Q 1 to 6 GroupQ of the core AVR device supported by this library variant
CH 4, 8, 12, 16, 32 Total number of channels supported by each library.
RS 1, 2, 3, 4, 8 Total number of rotors / sliders supported for the respective channel
counts mentioned in previous row.
The configuration sets for AVR Studio IDE are named according to the convention listed below
Configuration set for AVR Studio IDE
g_qt_k_rs
Field
Name
Values Comments
avrP avr25, avr4, avr 51, avr5,
xmega, uc3a, uc3b, uc3c
VersionP of the core AVR device supported by this library
variant
Q 1 to 6 GroupQ of the core AVR device supported by this library
variant
CH 4, 8, 12, 16, 32 Total number of channels supported by each library.
RS 1, 2, 3, 4, 8 Total number of rotors / sliders supported for the respective
channel counts mentioned in previous row.
Depending on your need, you need to select the right configuration required and build the project.69
Figure 5-11: Selecting the right configuration in the QTouch acquisition method example
applications in IAR –IDE
Figure 5-12 : Selecting the right configuration in QTouch acquisition method example
applications in AVR-6 IDE
5.6.11.2.2 Changing the settings to match your device
5.6.11.2.2.1 Processor settings
Once you have selected the appropriate example project and the configuration, you need to
ensure that the settings in the project are configured to reflect the correct device. The settings
include
• Device type ( CPU type ) for the project70 8207L-AT42-05/12
Figure 5-13 : Changing the processor settings for the examples in IAR IDE
Figure 5-14 : Changing the processor settings for the examples in AVR-Studio 6
5.6.11.2.3 Changing the library configuration parameters
The configuration parameters required for the library are specified in the touch_config.h file of the
examples under the custom user configuration section. Please refer to the example projects
provided with the QTouch libraries release for more information. The mandatory constants to be
defined are as listed below.71
Symbol / Constant name Range of values Comments
_QTOUCH_ This macro has to be
defined in order to use
QTouch libraries.
SNS & SNSK Section 5.7.1.5 provides
details on the range of
values allowed.
To be used if only single port pair is
needed for the design
SNS1 – SNSK1 & SNS2 –
SNSK2
Section 5.7.1.5.2 has
details on the range of
values allowed
To be used if two port pairs are needed for
the design
QT_NUM_CHANNELS 4, 8, 12, 16 for tinyAVR,
megaAVR and XMEGA
device libraries and 8, 16,
32 for UC3 device libraries.
_ROTOR_SLIDER_ Rotor / slider can be added
to the design, if this symbol
is defined
A library with rotor / slider functionality
already available needs to be selected if
this macro is to be enabled
_DEBUG_INTERFACE_ The debug interface code in
the example application will
be enabled if this macro is
enabled.
This will enable the application to output
QTouch measurement values to GPIO
pins, which can be used by a USB bridge
to view the output on Hawkeye or QTouch
Studio. This feature is currently supported
by EVK/TS 2080A and QT600 boards.
QT_DELAY_CYCLES 1 to 255 Please refer to section
QTOUCH_STUDIO_MASKS This macro needs to be
defined if QTouch Studio
Pin Configurator Wizard.is
used to generate the SNS
and SNSK masks.
Please refer to section 5.8.1
_STATIC_PORT_PIN_CONF_ This macro needs to be
defined only in case of 4
and 8 channel libraries with
interport configuration and
pin configurability.
Please refer to section 5.8.172 8207L-AT42-05/12
Figure 5-15 : Specifying the QTouch acquisition method library configuration parameters
for QTouch example projects
5.6.11.2.4 Using the example projects
The sample applications are shipped with the complete set of files required to configure, build,
execute and test the application for both IAR-workbench and AVR Studio IDEs.
The sample applications are provided for the evaluation kits and a few configurations for select
devices. The user can use the sample applications as a reference or baseline to configure
different configurations. Please ensure to change the configuration settings in the project options
to match the device selected.
To change the configuration settings of the sample applications,
1. Select the configuration from the list of configurations available.
2. If the user wishes to have a new name for the configuration to be used, a new
configuration can be added to the project.
3. If a different variant of the library needs to be used, remove the existing library in that
particular configuration and add the library variant that you require. Please refer to
5.7.1.4 for details on the different library variants. Update the linker options to specify
the library to be linked.
4. Specify the tunable configuration parameters for the project as illustrated in sections
5.6.11.2.2 and 5.6.11.2.3.73
5.6.11.3 Example applications for QMatrix acquisition method libraries
The QMatrix acquisition method libraries include example projects for some of the supported
devices. Example projects for both IAR IDE and AVR Studio IDE along with example applications
are provided for select devices using the QMatrix acquisition libraries. These sample applications
demonstrate the usage of the touch API’s to add touch sensing to an application. Refer to the
library selection guide for details on the example projects and sample applications supported for
the release.
5.6.11.3.1 Selecting the right configuration
The sample applications are built to support a maximum channel support configuration available
for that particular device for both IAR & AVR IDEs.
Internally there are two configurations for each device.
• ALL KEYS configuration : Supports only keys
• KEYS/ROTORS/SLIDERS configuration : Supports keys or rotors or sliders
concurrently
These configurations enable a set of stored options and a specific library to be selected in order
to build application using the specific library.
Figure 5-16 : Selecting the right configuration in the QMatrix acquisition method example
applications in IAR –IDE74 8207L-AT42-05/12
Figure 5-17 : Selecting the right configuration in the QMatrix acquisition method example
applications in AVR Studio IDE
5.6.11.3.2 Changing the library configuration parameters
The configuration parameters required for the library are specified in the touch_config.h file of the
examples. Please refer to the example projects provided with the QTouch libraries release for
more information. 75
Figure 5-18 : Specifying QMatrix acquisition library parameters in touch_config.h for
QMatrix projects
5.6.11.3.3 Using the example projects
The sample applications are shipped with the complete set of files required to configure, build,
execute and test the application for both IAR-workbench and AVR Studio IDEs.
The sample applications are provided for the evaluation kits and a few configurations for select
devices.
The user can use the sample applications as a reference or baseline to configure different
configurations. Please ensure to change the configuration settings in the project options to match
the device selected
To change the configuration settings of the sample applications,
1) Select the configuration from the list of configurations available as shown in section
5.6.11.3.1
2) If the user wishes to have a new name for the configuration to be used, a new
configuration can be added to the project
3) If a different variant of the library needs to be used, remove the existing library in that
particular configuration and add the library variant that you require. Please refer to library 76 8207L-AT42-05/12
selection guide for details on the different library variants. Update the linker options to
specify the library to be linked
4) Specify the tunable configuration parameters for the project as illustrated in 5.6.11.3.2
5) For QMatrix on XMEGA devices, please check if the pre-processor symbol _ATXMEGA_
is added in the project space or not.
5.6.11.4 Adjusting the Stack size when using IAR IDE
The example projects for IAR IDE, the CSTACK and RSTACK values are configured to account
for the requirements of the QTouch libraries and the included main.c file which illustrates the
usage of the touch API.
• Adjust the CSTACK and RSTACK values appropriately based on additional software
integrated or added to the examples.
Figure 5-19 : Modifying the stack size in IAR IDE
5.6.11.5 Optimization levels
The default configuration settings in sample projects which ship with the library are set to the
highest level of optimization for IAR and GCC variants of the libraries. The user might be required
to change this setting for debugging purposes
• In case of IAR, The optimizations tab in project configuration options specifies High.
• In case of GCC, the libraries are compiled with the –Os which signifies that the
Optimization for generating the library is maximum.77
Figure 5-20 : Specifying the optimization level in IAR IDE
5.6.11.6 Debug Support in Example applications
The EVK2080 and QT600 applications provide output debug information on standard GPIO pins
through the USB Bridge IC to PC software for display by AVR QTouch Studio. Similarly for
ATMEL devices that are not supported through EVK or QT600 kits, the output measurement
values can be viewed through AVR QTouch Studio using the same QDebug protocol and QT600
USB bridge.
If a QT600 bridge is not available, please refer to section 5.6.11.6.3 for more information on
observing the output touch measurement data without the use of a USB bridge or AVR QTouch
Studio.
5.6.11.6.1 Debug Support in the sample applications for EVK2080 and QT600 boards
The sample applications provided for the EVK2080 boards, QT600 boards and the other example
projects output debug information which is captured by a USB bridge chip and then routed to the
QTouch Studio for display.
Note:
The port and pins assigned for the QDebug protocol with the example projects are arbitrary and
have to be changed based on the project configuration chosen and pin availability.
A separate App note is available on the Atmel website (in QTouch libraries webpage) explaining
the QT600 debug protocol.
5.6.11.6.2 How to turn on the debug option
In the project options, the symbol definition _DEBUG_INTERFACE_ is used to enable reporting
the debug data. You can enable the debug interface by enabling the debug macro in
touch_config.h file.78 8207L-AT42-05/12
Figure 5-21 : Enabling and configuring the Debug Support
5.6.11.6.3 Debug Interface if USB Bridge board is not available
For the sample applications using the devices that are not supported on EVK2080 and QT600 the
debug interface code is not provided. This is because a separate USB bridge board is required to
read the data and display it on QTouch studio. However in this case the output touch
measurement data can still be viewed using the IAR or AVR Studio IDE when running the code in
debug mode using debug wire or emulator.
extern qt_touch_lib_measure_data_t qt_measure_data;
The qt_measure_data global variable contains the output touch measurement data. Refer to
section 5.6.4.3 for more information on the data type.
For GCC generated libraries the output touch measurement data can be observed on the watch
window through the pointer pqt_measure_data.
qt_touch_lib_measure_data_t *pqt_measure_data = &qt_measure_data;79
5.7 Library Variants
5.7.1 QTouch Acquisition method library variants
5.7.1.1 Introduction
Variants of the ATMEL QTouch Library based on QTouch Technology are available for a range of
ATMEL Microcontrollers. This section lists the different variants available. By following a simple
series of steps, the user can identify the right library variant to use in his application.
5.7.1.2 Support for different compiler tool chains
The QTouch acquisition method libraries are supported for the following compiler tool chains.
Table 7 Compiler tool chains supported for QTouch acquisition method libraries
Tool Version
IAR Compiler for 8bit AVR 6.10.0
IAR Embedded Workbench for AVR 6.10
Atmel Studio 6.0.x
IAR Compiler 32bit AVR 4.10.1
GCC – GNU Toolchain for AVR 8bit 3.4.0.1028
GCC – GCC Toolchain AVR 32bit 3.4.0.1028
IAR Embedded Workbench for ARM 6.30
GCC for ARM Sourcery G++ Lite for ARM EABI
V 2011.3.0.42
5.7.1.3 QTouch Acquisition method library naming conventions
The libraries are named according the convention listed below
5.7.1.3.1 Naming convention for libraries to be used with GCC tool chain
libg1_qt_k_rs.a
Field
name
Possible
values
Comments
coreP avr25
avr 35
avr 4
avr 51
avr 5
avrxmega2
avrxmega3
avrxmega4
avrxmega5
avrxmega6
avrxmega7
uc3a
uc3b
uc3c
sam3s
sam3u
VersionP of the core for AVR/ATSAM devices supported by this library variant
for tinyAVR and megaAVR devices. 80 8207L-AT42-05/12
sam3n
sam4s
CH 4, 8, 12, 16,
32
Total number of channels supported by each library.
RS 1, 2, 3, 4, 8 Total number of rotors / sliders supported for the respective channel counts
mentioned in previous row.
For example, the library variant “libavr25g1_8qt_k_2rs.a” supports the following configuration
• Device : tinyAVR or megaAVR device belonging to core version avr25
• Belongs to a set of devices of group 1 supported by this library
• Support a maximum of 8 channels
• Supports a maximum of up to 2 rotors / sliders.
5.7.1.3.2 Naming convention for libraries to be used with IAR Embedded Workbench
The libraries are named according the naming convention listed below
libg_qt_k_rs.r90
Field
name
Possible
values
Comments
coreP v1
v3
v3xmsf
v3xm
v4xm
v5xm
v6xm
uc3a
uc3b
uc3c
sam3s
sam3u
sam3n
VersionP of the for AVR/ATSAM devices supported by this library variant
variant for tinyAVR and megaAVR devices.
Q 1 to 3 GroupQ of the core AVR device supported by this library variant
CH 4, 8, 12, 16,
32
Total number of channels supported by each library.
RS 1, 2, 3, 4, 8 Total number of rotors / sliders supported for the respective channel counts
mentioned in previous row.
For example, the library variant “libv3g2_4qt_k_1rs.r90” supports the following configuration
• Device : tinyAVR or megaAVR device belonging to core version v3
• Belongs to a set of devices of group 2 supported by this library
• Supports a maximum of 4 channels
• Supports 1 rotor/slider
5.7.1.4 QTouch acquisition method library variants
lists the different QTouch acquisition method library variants supported for AVRs. Use this table
to select the correct library variant to be used in your application. Each row in the table below
indicates
• the corresponding Ports available for SNS and SNSK pins
• Compilers used for generating the libraries
• The library names to be selected for the requirements
Note: The libraries that are supported as listed in the table are only supported provided the
device memory requirements are also satisfied.81
Naming convention of the library
Maximum channels supported by the library.
Device Range
tinyAVR, megaAVR, XMEGA 4,8,12,16
UC3 8,16,32
ATSAM 32
Maximum number of rotor / sliders supported
NOTE:
• For 8-bit devices, ports which have less than 8 pins cannot be used by the QTouch
acquisition method libraries. Check the data sheet to determine the number of pins
supported for each port
5.7.1.5 Port combinations supported for SNS and SNSK pin configurations
For the list of all ports supported for each device please refer to the library selection guide. There
are no limitations for AVR devices (8bit and 32 bit) on the combination of SNS and SNSK port to
be used from QTouch libraries 4.0 release onwards.
For ATSAM devices the one port pair combinations supported are given below in the table.
One port pair supported combinations for
ATSAM
AA, BB, CC, AB, BA, AC, CA, BC, CB
5.7.1.5.1 Tips on pin assignments for the sensor design using one pair of SNS/SNSK
ports
This section lists tips on selecting the pin assignments when using a single port pair for the SNS
and SNSK Pins.
Design choice for the sensor Example Port configuration with pin assignments
SNSK & SNS pins are on different
ports, number of channels = 4
• If the SNS1(C) and SNSK1(B) pins are on two different ports, the
user should mount the sensors onto the corresponding pins such
as (PC0,PB0), (PC1,PB1), (PC2,PB2) and (PC3,PB3), when pin
configurability is not used.
• In case of pin configurability, sensors should be mounted on the
pins as selected based on rules illustrated in section 5.8.1
SNSK & SNS pins are on different
ports, number of channels = 8
• If the SNS1(C) and SNSK1(B) pins are on two different ports, the
user should mount the sensors onto the corresponding pins such
as (PC0,PB0), (PC1,PB1), (PC2,PB2) and so on, When pin
configurability is not used.
• When using pin configurability, sensors should be mounted on the
pins as selected based on rules illustrated in section 5.8.1
• When pin configurability is not used, channel 0 will be on (PC0,
PB0) pins, channel 1 will be on (PC1, PB1) pins and so on up to
channel 7 will be on (PC7, PB7) pins.
• When using pin configurability, channel should be assigned as
given in section 5.6.6.1.1.282 8207L-AT42-05/12
•
SNSK & SNS pins are on different
ports, number of channels = 32
when using UC3 device
• If the SNS1(B) and SNSK1(A) pins are on two different ports, the
user should mount the sensors onto the corresponding pins such
as (PB0,PA0), (PB1,PA1), (PB2,PA2)..
• In this case channel 0 will be on (PB0, PA0) pins, channel 1 will be
on (PB1, PA1) pins and so on up to channel 31 will be on (PB31,
PA31) pins.
SNSK & SNS pins are on the
same port, number of channels =
2
• If the use of SNS1(A) and SNSK1(A) pins are on the same port,
the user should always have the configuration (PA0, PA1) & (PA2,
PA3). In this case channel 0 will be on (PA0, PA1) pins; channel 1
will be on (PA2, PA3) pins. The even pins of the port are used as
SNS1 pins and odd pins of the port are used as SNSK1 pins
• When pin configurability is used, sensors should be mounted on
the pins as selected as per the rules illustrated in section 5.8.1 and
channels should be assigned as given in section 5.6.6.1.1.4
SNSK & SNS pins are on the
same port, number of channels =
4
• If the use of SNS1(A) and SNSK1(A) pins are on the same port,
the user should always have the configuration (PA0, PA1), (PA2,
PA3), (PA4, PA5) & (PA6, PA7). In this case channel 0 will be on
(PA0, PA1) pins, channel 1 will be on (PA2, PA3) pins and so on
up to channel 4 will be on (PA6, PA7) pins. The even pins of the
port are used as SNS1 pins and odd pins of the port are used as
SNSK1 pins, when pin configurability is not being used.
• When using pin configurability, sensors should be mounted on the
pins as selected as per the rules illustrated in section 5.8.1 and
channels should be assigned as given in section 5.6.6.1.1.4
SNSK & SNS pins are on the
same port, number of channels =
16
( Available only for UC3 devices if
more than 4 channels are to be
used on a single port. For
tinyAVR, megaAVR, XMEGA
devices up to 8 channels with
SNS and SNSK on same ports
refer to section 5.7.1.5.2 )
• This configuration is available only for UC3 library variants.
• In the use of SNS(A) and SNSK(A) pins are on the same port, the
user should always have the configuration (PA0, PA1), (PA2,
PA3), (PA4, PA5) & so on. In this case channel 0 will be on (PA0,
PA1) pins, channel 1 will be on (PA2, PA3) pins and so on up to
channel 15 will be on (PA30, PA31) pins. The even pins of the port
are used as SNS pins and odd pins of the port are used as SNSK
pins
SNSK & SNS pins are on the
same port, number of channels =
16
( Available only for SAM devices)
• If the use of SNS(A) and SNSK(A) pins are on the same port, the
user should always have the configuration (PA0, PA1), (PA2,
PA3), (PA4, PA5), (PA6, PA7) and so on.
• In this case channel 0 will be on (PA0, PA1) pins, channel 1 will be
on (PA2, PA3) pins and so on up to channel 15 will be on (PA30,
PA31) pins.
• The even pins of the port are used as SNS pins and odd pins of
the port are used as SNSK pins83
5.7.1.5.2 Port combinations supported for two port pair SNS and SNSK pin
configurations
For the list of all ports supported for each device please refer to the library selection guide. There
are no limitations on the combination of SNS and SNSK port to be used from QTouch libraries 4.0
release onwards.
For ATSAM devices the total two port pairs supported combinations are given below in the table.
Two port pairs supported combinations for
ATSAM
AA_BB, BB_AA, AA_CC, CC_AA, BB_CC,
CC_BB, AA_BC, AA_CB, BB_AC, BB_CA,
CC_BA, CC_AB
5.7.1.5.2.1 Tips on pin assignments for the sensor design using two pairs of SNS / SNSK
ports
This section lists tips on selecting the pin assignments when using a single port pair for the SNS
and SNSK Pins.
Design choice for the sensor Example Port configuration with pin assignments
SNSK1-SNS1 & SNSK2-SNS2 pins
are all on different ports, number of
channels = 16
(Use the 16channel library in this
case. Ensure the port definitions for
SNS1,SNSK1,SNS2,SNSK2 are all in
place)
• E. g. SNS1(D), SNSK1(B) & SNS2(C), SNSK2(A)
• Recommended configuration: (PD0, PB0), (PD1, PB1),..(PD7,
PB7), (PC0,PA0).. to (PC7, PA7). In this case channel 0 will be
on (PD0, PB0) pins, channel 1 will be on (PD1, PB1) pins,
channel 8 will be on (PC0, PA0), channel 9 will be on (PC1,
PA1) and so on up to channel 15 will be on (PC7, PA7) pins.
• However, the user can mount the sensors on pins as selected
as per the rules illustrated in section 5.8.1 and channels
should be assigned as given in section 5.6.6.1.1.2
SNSK1-SNS1 are on same port &
SNSK2-SNS2 pins are on same port,
number of channels = 8
(Use the 8channel library in this case.
Ensure the port definitions for
SNS1,SNSK1,SNS2,SNSK2 are all in
place)
• E.g. SNS1(K), SNSK1(K) & SNS2(H), SNSK2(H) on same
ports,
• Recommended configuration: In case Pin configurability is not
used, (PK0, PK1), (PK2, PK3),..(PK6, PK7), (PH0,PH1).. to
(PH6, PH7).In this case channel 0 will be on (PK0, PK1) pins,
channel 1 will be on (PK2, PK3) pins, channel 4 will be on
(PH0, PH1), channel 5 will be on (PH2, PH3) and so on up to
channel 7 will be on (PH6, PH7) pins. The even pins of the port
are used as SNS pins and odd pins of the port are used as
SNSK pins.
• When pin configurability is used, sensors should be mounted
on the pins as selected as per the rules illustrated in section
5.8.1 and channels should be assigned as given in section
5.6.6.1.1.2
SNSK1-SNS1 are on different ports &
SNSK2-SNS2 pins are on same port,
number of channels = 12
(Use the 12channel library in this
case. Ensure the port definitions for
SNS1,SNSK1,SNS2,SNSK2 are all in
place)
• E.g. SNS1(H), SNSK1(F) on different ports & SNS2(E),
SNSK2(E) on same ports.
• Recommended configuration : In case Pin configurability is not
used, (PH0, PF0), (PH1, PF1),..(PH7, PF7), (PE0,PE1).. to
(PE6, PE7). In this case channel 0 will be on (PH0, PF0) pins,
channel 1 will be on (PH1, PF1) pins... channel 8 will be on
(PE0,PE1), channel 9 will be on (PE2,PE3) and so on up to
channel 11 will be on (PH6, PH7) pins. The even pins of the
port E are used as SNS pins and odd pins of the port E are
used as SNSK pins.
• When pin configurability is used, sensors should be mounted
on the pins as selected as per rules illustrated in section 5.8.1
and channels should be assigned as given in section 84 8207L-AT42-05/12
5.6.6.1.1.2 and section 5.6.6.1.1.4
SNSK1-SNS1 are on same port &
SNSK2-SNS2 pins are on different
ports, number of channels = 12
(Use the 12channel library in this
case. Ensure the port definitions for
SNS1,SNSK1,SNS2,SNSK2 are all in
place)
• E.g. SNS1(G), SNSK1(G) on different ports & SNS2(B),
SNSK2(D) on same ports
• Recommended configuration: In case Pin configurability is not
used, (PG0, PG1), (PG2, PG3),..(PG6, PG7), (PB0,PD0)... to
(PB7, PD7). In this case channel 0 will be on (PG0, PG1) pins,
channel 1 will be on (PG2, PG3) pins... channel 3 will be on
(PG6, PG7), channel 4 will be on (PB0,PD0) and so on up to
channel 11 will be on (PB7, PD7) pins. The even pins of the
port G are used as SNS pins and odd pins of the port G are
used as SNSK pins
• When pin configurability is used, sensors should be mounted
on the pins as selected as per rules illustrated in section 5.8.1
and channels should be assigned as given in section
5.6.6.1.1.2 and section 5.6.6.1.1.4
5.7.1.6 Sample applications and Memory requirements for QTouch acquisition method
libraries
Refer to the library selection guide for memory requirements for each of the libraries supported in
the release.
5.7.2 QMatrix acquisition method library variants
5.7.2.1 Introduction
Variants of the ATMEL QTouch Library based on Matrix™ acquisition technology are available for
a range of ATMEL Microcontrollers. Refer to the library selection guide (C:\ Program Files\Atmel\
Atmel_QTouch_Libaries_5.x\Library_Selection_Guide.xls) for the list of devices currently
supported for QMatrix.
5.7.2.2 Support for different compiler tool chains
The QMatrix acquisition method libraries are supported for the following compiler tool chains.
Tool Version
IAR Compiler 6.10
IAR Embedded Workbench 6.10
Atmel Studio 6 6.0.x
GCC – GNU Toolchain for AVR 3.4.0.1028
IAR Compiler 32bit AVR 4.10.1
GCC – GNU Toolchain for AVR32 3.4.0.1028
5.7.2.3 QMatrix Acquisition method library naming conventions
The libraries are named according the naming convention listed below
Tool Chain Naming convention
GCC Tool Chain lib_qm_x_y__rs.a
IAR –EWAR lib_qm_x_y__rs.r9085
Field
name
Possible values Comments
D Common for IAR & GCC:
ATtiny167,
ATmega128rfa1,
ATmega8535
Specific to IAR:
v1g1s0 (ATtiny44,
ATtiny84)
v1g1s1 (ATtiny48,
ATtiny88)
v1g1s2(ATtiny461,
ATtiny861)
ATmega16a
v1g2s1 (ATmega48PA,
ATmega88PA)
v3xmsf (ATxmega16A4,
ATxmega16D4,
ATxmega32A4,
ATxmega32D4)
v3xm (ATxmega64A3)
v4xm(ATxmega64A1)
v5xm(ATxmega128A3,
ATxmega192A3,
ATxmega256A3,
ATxmega256A3B)
v6xm(ATxmega128A1)
v3g3 (ATmega165P,
ATmega325P,
ATmega645,
ATmega164p,
ATmega324p,
ATmega324pa,
ATmega644p,
ATmega168p,
ATmega328p,
AT90CAN32,
AT90CAN64
)
v3g5 ( AT90CAN128,
AT90USB1286,
AT90USB1287,
ATmega1280,
ATmega1281
)
v3g6 ( AT90USB162
)
v3g7 ( AT90USB646,
Indicates the device / core group name in short form.
For XMEGA Devices, Core groups are taken which
follows
As below for both GCC and IAR
Supported XMEGA Devices
ATxmega16A4,
ATxmega16D4,
ATxmega32A4,
ATxmega32D4,
ATxmega64A1
ATxmega128A1
ATxmega64A3
ATxmega128A3,
ATxmega192A3,
ATxmega256A3,
ATxmega256A3B)86 8207L-AT42-05/12
AT90USB647
)
Specific to GCC:
avr25g1s0 (ATtiny44,
ATtiny84)
avr25g1s1 (ATtiny48,
ATtiny88)
avr25g1s2(ATtiny461,
ATtiny861)
ATmega16
avr4g1s1 (ATmega48P,
ATmega88P)
avr5g4 ( AT90USB646,
AT90USB647
)
avr5g6 ( AT90USB162
)
avrxmega2 (ATxmega16A4,
ATxmega16D4,
ATxmega32D4)
avrxmega3 (ATxmega32A4)
avrxmega4 (ATxmega64A3)
avrxmega5(ATxmega64A1)
avrxmega6(ATxmega128A3,
ATxmega192A3,
ATxmega256A3,
ATxmega256A3B)
avrxmega7(ATxmega128A1)
avr5g3 (ATmega165P,
ATmega325P,
ATmega645,
ATmega164p,
ATmega324p,
ATmega324p,
ATmega644p,
ATmega168p,
ATmega328p,
AT90CAN32,
AT90CAN64
)
avr51g2 ( AT90CAN128,
AT90USB1286,
AT90USB1287,
ATmega1280,
ATmega1281
)
AT32UC3C0512
NC 4,8,16,24,32,56,64 Indicates the maximum number of channels that the 87
library supports
56 (8 x 7) support only for ATXmega Devices.
24((8 x 3) support only for 32 Bit Devices.
NX 4,8 Indicates the number of X-Lines that the library needs
for supporting the listed number of channels.
The X lines on a PORT always start with Least
Significant Bit of the PORT.
Ex: #define PORT_X_1 B in case of a 4x2
QMatrix library means
X0,X1,X2,X3 are on PB0,PB1,PB2,PB3
NY 1,2,3,4,7,8 Indicates the number of Y-Lines that the library needs
for supporting the listed number of channels
NY=7 support only for ATXmega Devices
NY=3 support only for 32Bit Devices
CFG k
krs
k – library variant supports only keys
krs – library variant supports keys, Rotors and Sliders
NRS 0,1,2,3,4,8 Maximum number of rotor sliders that the library
supports.
NRS=3 support only for 32Bit Devices
The table below provides a few examples of the naming convention.
Example Library name Configuration supported
libavr51g2_8qm_4x_2y_krs_2rs.a • Compiler tool chain : GCC
• Device : ATMega164P
• 8 Channels
• 4 X lines
• 2 Y lines
• Supports Keys, Rotors and Sliders ( krs )
• 2 Rotors and Sliders
libavr25g1s1_16qm_8x_2y_k_0rs.r90 • Compiler tool chain : IAR
• Device : ATTiny88
• 16 Channels
• 8 X lines
• 2 Y lines
• Supports only keys ( k)
• 0 Rotors and Sliders
5.7.2.4 QMatrix acquisition method library variants
5.7.2.4.1 Devices supported for QMatrix Acquisition
Refer to the Library_selection_guide.xls for the list of devices supported for QMatrix for this
release.
5.8 PIN Configuration for QTouch Libraries
5.8.1 Pin Configuration for QTouch Acquisition Method
Pin configurability for QTouch acquisition method is provided for 8Bit AVR’s. QTouch
acquisition method libraries can be used to configure SNS and SNSK on any pins of the
port. But few rules should be followed while assigning the SNS and SNSK on particular
pins. These rules are internal to the library. But QTouch Studio –Pin Configuration Wizard 88 8207L-AT42-05/12
can be used to assign SNS and SNSK on the pins and rules are internally taken care in the
QTouch Studio Pin Configuration Wizard.
By default, for 4 and 8 channel QTouch acquisition libraries, the channel numbering follows
the pin number of the port.
To use the pin configurability, enable the macro _STATIC_PORT_PIN_CONF_ in the
project options or define the macro in the touch_config.h file.
To use the pin configurability feature, the SNS_array and SNSK_array masks are exported
for the user, which needs to be initialized. These SNS_array and SNSK_array masks can
be taken from the QTouch Studio Pin Configuration Wizard and can be copied at
appropriate place in the main.c file as explained in the example projects provided.
QTOUCH_STUDIO_MASKS macro is used for providing pin configurability feature for
QTouch Acquisition method libraries.
In case the macro QTOUCH_STUDIO_MASKS enabled in project space,
SNS_array and SNSK_array takes values that are supplied by the user in main.c files.
This will reduce the code memory foot print of the library.
In case the macro QTOUCH_STUDIO_MASKS is not enabled in project space,
SNS_array and SNSK_array are calculated internal to the library according to the
configured sensors.
Note:
1. Port pin configurability is enabled for the following configurations,
4- channel intraport configuration
8-channel intraport configuration
12-channel configuration
16- channel configuration
2. In case, the user wants to use the pin configurability for the other supported
configurations, (4- channel interport and 8-channel interport), the user has to enable the
macro _STATIC_PORT_PIN_CONF_ in his project space.
5.8.1.1 Rules for configurable SNS-SNSK Mask Generation
X X X
SNS1=PORTA
PORT PAIR 1 Ch2 Ch1 Ch0
X X X
SNSK1=PORTB89
X X X
SNS2=PORTC
PORT PAIR 2 Ch5 Ch4 Ch3
X X X
SNSK2=PORTD
1. The channel numbers are allocated based on enabled SNS pins starting from LSBit of
port 1(SNS1) and ending with MSBit of port 2(SNS2).
2. The number of SNS pins in a port pair should be equal to the SNSK pins in the same port
pair so it can form a pair.
3. The first SNS port pin should always be mapped to the first SNSK port pin in any port
pair. Similarly the second SNS port pin should always be mapped to second SNSK pin
and so on.
4. Even sensors with in a port pair should be placed in one mask and odd sensors with-in a
port pair should be placed in the second mask. In case of interport, first channel should
always start with odd masks and then even masks is filled .
5. All the three channels for ROTORS and SLIDERS should be placed within the same
mask. And should be in the same port pair.
6. Keys on adjacent channels should be placed on different masks.
7. For 8 channel case when 2 ports are enabled, the pins for the 8 channels can be spread
on the 2 ports. The pin configuration is done based on the rules mentioned above.
8. For 16 channel case when 2 ports are enabled, all the pins for the 16 channels are
allocated among the pins of the 2 ports.
5.8.1.1.1 Example for 8 channel interport mask Calculation with one port pair
X X X
SNS1=PORTA
Ch2 Ch1 Ch0
X X X
SNSK1=PORTB
This example is for interport 8 channel library with only one port pair used.
Channel0 is A0B2,Channel1 is A3B5 and Channel2 is A6B7 are enabled for the 8
channel library.
The SNS_array and SNSK_array masks are calculated by the Qtouch Studio with rules
mentioned above.
In this case, the SNS_array and SNSK_array values will be as mentioned below:90 8207L-AT42-05/12
SNS_array[0][0]=0x41; (SNS even mask for port pair 1)
SNS_array[0][1]=0x08; (SNS odd mask for port pair 1)
SNS_array[1][0]=0x00; (SNS even mask for port pair 2)
SNS_array[1][1]=0x00; (SNS odd mask for port pair 2)
SNSK_array[0][0]=0x84; (SNSK even mask for port pair 1)
SNSK_array[0][1]=0x20; (SNSK odd mask for port pair 1)
SNSK_array[1][0]=0x00; (SNSK even mask for port pair 2)
SNSK_array[1][1]=0x00; (SNSK odd mask for port pair 2)
As there is no second port pair used for this, so that’s why SNS_array[1][0],
SNS_array[1][1], SNSK_array[0][1] and SNSK_array[1][1] are having value zero.
5.8.1.1.2 Example for 8 channel intraport mask Calculation with two port pairs
X X X
SNS1=PORTA
Ch2 Ch1 Ch0
X X X
SNSK1=PORTA
X X X
SNS2=PORTB
Ch5 Ch4 Ch3
X X X
SNSK2=PORTB
This example is for intraport 8 channel library with two port pair used.
Channel0 is A1A3,Channel1 is A4A5 and Channel2 is A6A7 are enabled in the first port
pair. Channel3 is B1B2,Channel4 is B3B4 and Channel5 is B5B6 are enabled in the
second port pair.
The SNS_array and SNSK_array masks are calculated by the Qtouch Studio with rules
mentioned above.
In this case, the SNS_array and SNSK_array values will be as mentioned below:91
SNS_array[0][0]=0x52; (SNS even mask for port pair 1)
SNS_array[0][1]=0x00; (SNS odd mask for port pair 1)
SNS_array[1][0]=0x2a; (SNS even mask for port pair 2)
SNS_array[1][1]=0x00; (SNS odd mask for port pair 2)
SNSK_array[0][0]=0xa8; (SNSK even mask for port pair 1)
SNSK_array[0][1]=0x00; (SNSK odd mask for port pair 1)
SNSK_array[1][0]=0x54; (SNSK even mask for port pair 2)
SNSK_array[1][1]=0x00; (SNSK odd mask for port pair 2)
In case of Intraport, odd SNS_array and SNSK_array masks are always zero.So that’s
why SNS_array[0][1] ,SNS_array[1][1], SNSK_array[0][1] and SNSK_array[1][1] are zero
for both the port pairs.
5.8.1.1.3 Example for 12 channel intraport-interport mask Calculation with two port
pairs
X X X
SNS1=PORTA
Ch2 Ch1 Ch0
X X X
SNSK1=PORTA
X X X
SNS2=PORTB
Ch5 Ch4 Ch3
X X X
SNSK2=PORTD
This example is for intraport-interport 12 channel library with two port pair used.
Channel0 is A1A3,Channel1 is A4A5 and Channel2 is A6A7 are enabled in the first port
pair. Channel3 is B1D2,Channel4 is B3D4 and Channel5 is B5D6 are enabled in the
second port pair.
The SNS_array and SNSK_array masks are calculated by the Qtouch Studio with rules
mentioned above.
In this case, the SNS_array and SNSK_array values will be as mentioned below:92 8207L-AT42-05/12
SNS_array[0][0]=0x52; (SNS even mask for port pair 1)
SNS_array[0][1]=0x00; (SNS odd mask for port pair 1)
SNS_array[1][0]=0x22; (SNS even mask for port pair 2)
SNS_array[1][1]=0x08; (SNS odd mask for port pair 2)
SNSK_array[0][0]=0xa8; (SNSK even mask for port pair 1)
SNSK_array[0][1]=0x00; (SNSK odd mask for port pair 1)
SNSK_array[1][0]=0x44; (SNSK even mask for port pair 2)
SNSK_array[1][1]=0x10; (SNSK odd mask for port pair 2)
As the first port pair is intraport, so that’s why SNS_array[0][1] and SNSK_array[0][1] are
zero as odd masks are always zero in case of Intraport.
5.8.1.1.4 Example for 16 channel intreport-interport mask Calculation with two port
pairs
X X X
SNS1=PORTA
PORT PAIR 1 Ch2 Ch1 Ch0
X X X
SNSK1=PORTB
X X X
SNS2=PORTC
PORT PAIR 2 Ch5 Ch4 Ch3
X X X
SNSK2=PORTD
This example is for interport-interport 16 channel library with two port pair used.
Channel0 is A2B0,Channel1 is A4B3 and Channel2 is A5B6 are enabled in the first port
pair. Channel3 is C1D2,Channel4 is C3D3 and Channel5 is C5D4 are enabled in the
second port pair.
The SNS_array and SNSK_array masks are calculated by the Qtouch Studio with rules
mentioned above.93
In this case, the SNS_array and SNSK_array values will be as mentioned below:
SNS_array[0][0]=0x24; (SNS even mask for port pair 1)
SNS_array[0][1]=0x10; (SNS odd mask for port pair 1)
SNS_array[1][0]=0x22; (SNS even mask for port pair 2)
SNS_array[1][1]=0x08; (SNS odd mask for port pair 2)
SNSK_array[0][0]=0x41; (SNSK even mask for port pair 1)
SNSK_array[0][1]=0x08; (SNSK odd mask for port pair 1)
SNSK_array[1][0]=0x14; (SNSK even mask for port pair 2)
SNSK_array[1][1]=0x08; (SNSK odd mask for port pair 2)
5.8.1.2 How to Use QTouch Studio For Pin Configurability
Note: The Qtouch Composer is available for few select set of devices.But user can use Qtouch
Studio 4.4 for the devices which are not supported in Qtouch Composer.
The following steps describe the details on how to use pin configurability for QTouch
Acquisition method:
1. Open AVR QTouch Studio .Enable the Design Mode Radio button on the left hand side of
the screen.
Figure 5-22 Selecting the Design mode in the AVR QTouch Studio
1. Go to File Menu option and click New Design.94 8207L-AT42-05/12
Figure 5-23 Selecting the New Design in the AVR QTouch Studio
2. In the Create New Design Window, give the Project name and Kit Technology (QTouch in
this case) and and Number of sensors (Keys/Rotors/Sliders) and click Create Design.
Figure 5-24: Creating New Design in the AVR QTouch Studio
3. After Creating Design, the new screen pops up which shows all the sensors which have
been created.95
Figure 5-25: New Design Sensors in the AVR QTouch Studio virtual kit
4. Now Go to Tools->Pin Configuration Wizard.Pin configuration
Figure 5-26: Selecting the pin configuration wizard for theDesign
5. Pin configuration Window will pop up with the information on the usage of the tool.
Click Next to proceed to the configuration.96 8207L-AT42-05/12
Figure 5-27: : Start page of the wizard
6. Select the MCU and click Next as shown below.97
Figure 5-28: Selecting the MCU for the New Design
7. Select the SNS and SNSK ports needs for the design and click Next.
Figure 5-29: Selecting SNS and SNSK ports in the New Design98 8207L-AT42-05/12
8. Select the pins used for the design and click Next
If there is error in the selection of the pins (Ex: conflictin pins used), a red marker will be
appear and the user cannot proceed to next step in configuration until the user has done the
correct pin selection.
Now once the selection is done without errors, Click Next
Figure 5-30: Selecting the SNS and SNSK Port Pins in the new Design( With Error)99
Figure 5-31: Selecting the SNS and SNSK Port Pins in the new Design( Without Error)
Once the pins are selected, Pin Wizard will provide the summary report .Check whether details
are correct as specified.Click Next
Figure 5-32: Summary report100 8207L-AT42-05/12
Figure 5-33: Code Generation tab in Pin Configuration wizard
9. In the New Window Screen, the code is shown on the
screen.QTOUCH_STUDIO_MASKS needs to be enabled in the project option or in
touch_ config.h file. And in the main.c file, this code SNS_array and SNSK_array needs
to be copied from here and put under QTOUCH_STUDIO_MASKS macro as shown
below in the main.c file:
#ifdef QTOUCH_STUDIO_MASKS
SNS_array[0][0]=0x09;
SNS_array[0][1]=0x22;
SNS_array[1][0]=0x00;
SNS_array[1][1]=0x00;
SNSK_array[0][0]=0x14;
SNSK_array[0][1]=0x88;
SNSK_array[1][0]=0x00;
SNSK_array[1][1]=0x00;
#endif
Note:
1. To use 4 and 8 channel libraries(interport case) for pin configurability ,
_STATIC_PORT_PIN_CONF_ macro needs to be enabled in the touch_config.h file.101
2. QTOUCH_STUDIO_MASKS needs to be enabled if using pin configurability .If not enabled
then, static pin mapping will work same as in the earlier versions of the libraries
5.8.2 Pin Configuration for QMatrix Acquisition Method
The QMatrix acquisition method libraries needs to be used after configuring X and YA and
YB lines on IO pins of the port as described in the configuration rules described in the
section below. The QTouch Studio Pin Configurator Wizard can be used to assign X, YA,
YB, SMP lines on the pins and rules are internally taken care in the Qtouch Studio Pin
Configurator Wizard.
The snippets can be taken from the QTouch Studio Pin Configurator Wizard and copied to
appropriate places in the main.c and touch_ config.h files in the example projects provided.
5.8.2.1 Configuration Rules:
1. The X lines can be configured on different ports up to a maximum of 3 ports
Ex: NUM_X_PORTS = 3 (maximum value supported). However the possible values
are NUM_X_PORTS = 1 or NUM_X_PORTS = 2 or NUM_X_PORTS = 3
2. The X lines can be configured on the three different ports.
3. The X lines can be configured on any pins of the ports selected above
Ex: X0 on PB2, X1 on PD5, X2 on PE0, X3 on PD1( when NUM_X_LINES= 4),
Provided that these pins do not conflict with the other pins for touch sensing or with the
host application usage.
4. The Y lines can be configured on the any of the pins of the ports selected
Ex: Any pins on the PORT_YA and PORT_YB selected.
Suppose, PORT_YA is D, and PORT_YB is C
Since, pin 5 and pin 1 PORTD are already used for X lines(X1, X3), the user can select
any of the remaining pins for Y0A lines. Suppose that Y0 is on pin2 and Y1 is on pin6
Hence, Y0A – PD2, Y0B – PC2, Y1A – PD6, Y1B – PC6,
5. All the Qmatrix usage Pins X lines,YA lines, YB lines and SMP line can be on same
port.Both YA and YB lines can share the same port. And the YA and YB need not be on
same corresponding pins of the ports.The Macro SHARED_YAYB should be defined as 1
if YA and YB are on same port else should be defined as 0.
6. The PORT_YB is fixed for each device and should be same as the PORT on which the
ADC input pins are available.
7. The SMP pin can be configured on any of the IO PORT pins available.
Ex: PORT_SMP = D
SMP_PIN = 7 as this pin is not being used by touch sensing.
Note:
Please take care that the touch sensing pins do not conflict with other IO pins used by host
application 102 8207L-AT42-05/12
5.8.2.2 How to use QTouch Studio for Pin Configurability:
Note: The Qtouch Composer is available for few select set of devices.But user can use Qtouch
Studio 4.4 for the devices which are not supported in Qtouch Composer. Also YA,YB shared on
same port feature is available in Qtouch Composer and not available in Qtouch Studio
4.4.Please refer section 5.6.10.3
The following steps describe the details on how to use pin configurability for QMatix
Acquisition method:
1. Open AVR Qtouch Studio .Enable the Design Mode Radio button on the left hand
side of the screen..
Figure 5-34: Selecting the Design mode in the AVR QTouch Studio
2. Go to File Menu option and click New Design103
Figure 5-35: Selecting New Design
3. In the Create New Design Window, give the Project name and Kit Technology
(QMatrix in this case) and Number of sensors (Keys/Rotors/Sliders) and click Create
Design.
Figure 5-36 Creating New Design in the AVR QTouch Studio104 8207L-AT42-05/12
After Creating Design , the new design mode shows the virtual kit view with sensors that
have been created in some order.
Figure 5-37: New Design Sensors in the AVR QTouch Studio
4. Now Go to Tools->Pin Configuration Wizard as shown below.
Figure 5-38: Selecting the pin configuration wizard
5. Pin configuration Window will pop up with the information on the usage of the tool.
Click Next to proceed.105
Figure 5-39: Start window of the configuration wizard
6. .Select the MCU and click Next as shown below.
Figure 5-40: MCU selection window from the configuration wizard.
7. Select the Channels needed for the design from the list provided and click Next.106 8207L-AT42-05/12
If 6 channels are needed, the next immediate value that suits the design needs to be
selected. Ie., 8 channels (4 x 2 ) configuration.
Figure 5-41: Selecting channels and configuration in the New Design
8. Select the pins used for the design and click Next.
If there is error in the selection of the pins (Ex: conflictin pins used), a red marker will be
appear and the user cannot proceed to next step in configuration until the user has done the
correct pin selection.
Now once the selection is done without errors, Click Next.107
Figure 5-42: Selecting the X,YA,YB,SMP Pins in the new Design with errors.
Figure 5-43: Selecting the X,YA,YB,SMP Pins in the new Design without errors.
Once the pins are selected, Pin Wizard will provide the summary report .Check whether details
are correct as specified.Click Next.108 8207L-AT42-05/12
If there are some errors that are found in the summary report, the user can click “back” button
and modify the changes needed.
Figure 5-44: Summary report
Figure 5-45: Code Generation tab in Pin Configuration wizard
9. The code is shown in the New Window Screen.
Note: Use FILL_OUT_YA_LINE_INFO and FILL_OUT_YB_LINE_INFO code instead of 109
FILL_OUT_Y_LINE_INFO as now YA and YB can be shared on same port.
The code can be copied using the “copy code” and pasted in the main.c and touch_config
.h file,
a. In touch _config.h,
Copy the following header definitions as part of the preprocessor directives in
the project space or in the beginning of the file
#define NUM_X_PORTS 2
#define PORT_X_1 B
#define PORT_X_2 D
#define PORT_YA D
#define PORT_YB C
#define SMP_PORT D
#define SMP_PIN 7
#define SHARED_YAYB 0
b. In main.c ,
Copy the code as below
x_line_info_t x_line_info[NUM_X_LINES]= {
FILL_OUT_X_LINE_INFO(1,1);
FILL_OUT_X_LINE_INFO(2,2);
FILL_OUT_X_LINE_INFO(1,3);
FILL_OUT_X_LINE_INFO(2,0);
};
y_line_info_t ya_line_info[NUM_Y_LINES]= {
FILL_OUT_YA_LINE_INFO(1);
FILL_OUT_YA_LINE_INFO(3);
};
y_line_info_t yb_line_info[NUM_Y_LINES]= {
FILL_OUT_YB_LINE_INFO(1);
FILL_OUT_YB_LINE_INFO(3);
};
Note: If YA,YB shared on same port feature is needed , then apart from the above Macros
#define SHARED_YAYB needs to be enabled as 1.
5.9 MISRA Compliance Report
This section lists the compliance and deviations for MISRA standards of coding practice for the
QTouch and QMatrix acquisition method libraries.110 8207L-AT42-05/12
5.9.1 What is covered
The QTouch and QMatrix acquisition method libraries adhere to the MISRA standards. The
additional reference code provided in the form of sample applications is not guaranteed to be
MISRA compliant.
5.9.2 Target Environment
Development Environment IAR Embedded Workbench
MISRA Checking software The MISRA C Compliance has been performed for the library
using MISRA C 2004 Rules in IAR Workbench development
environment.
MISRA Rule set applied MISRAC 2004 Rule Set
5.9.3 Deviations from MISRA C Standards
5.9.3.1 QTouch acquisition method libraries
The QTouch acquisition method libraries were subject to the above mentioned MISRA
compliance rules. The following exceptions have not been fixed as they are required for the
implementation of the library.
Applicable
Release
QTouch libraries version
5.0
Rule No Rule Description Exception noted / How it is addressed
1.1 Rule states that all code
shall conform to ISO 9899
standard C, with no
extensions permitted.
This Rule is not supported as the library
implementation requires IAR extensions like
__interrupt. These intrinsic functions relate to
device hardware functionality, and cannot
practically be avoided.
10.1 Rule states that implicit
conversion from Underlying
long to unsigned long
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
10.6 This Rule says that a 'U'
suffix shall be applied to all
constants of 'unsigned' type
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
14.4 Rule states that go-to
statement should not be
used.
The library uses conditional jump instructions to
reduce the code footprint at a few locations and
this is localized to small snippets of code. Hence
this rule is not supported.
19.10
Rule states that In the
definition of a function-like
macro, each instance of a
parameter shall be enclosed
in parenthesis
There is one instance where the library breaks this
rule where two macro definitions are combined to
form a different symbol name. Usage of
parenthesis cannot be used in this scenario.
19.12 Rule states that there shall
be at most one occurrence
of the # or ## preprocessor
operator in a single macro
definition
There is one instance in the library where this rule
is violated where the library concatenates two
macro definitions to arrive at a different definition. 111
5.9.3.2 QMatrix acquisition method libraries
The QMatrix acquisition method software was subject to the above mentioned MISRA compliance
rules. The following exceptions have not been fixed as they are required for the implementation of
the library.
Applicable
release
QTouch libraries ver 5.0
Rule No Rule Description Exceptions Reason
1.1 Rule states that all code
shall conform to ISO 9899
standard C, with no
extensions permitted.
This Rule is not supported as the library
implementation requires IAR extensions like
__interrupt. These intrinsic functions relates to
device hardware functionality, and cannot
practically be avoided
10.1 Rule states that Illegal
implicit conversion from
Underlying long to unsigned
long
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
10.6 This Rule says that a 'U'
suffix shall be applied to all
constants of 'unsigned' type
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
19.10
Rule states that In the
definition of a function-like
macro, each instance of a
parameter shall be enclosed
in parenthesis
There is one instance where the library breaks this
rule where two macro definitions are combined to
form a different symbol name. Usage of
parenthesis cannot be used in this scenario.
19.12 Rule states that there shall
be at most one occurrence
of the # or ## preprocessor
operator in a single macro
definition
There is one instance in the library where this rule
is violated where the library concatenates two
macro definitions to arrive at a different definition.
5.10Known Issues
Issue Cause Remedy / workaround
Buiding QTouch Libraries Release 5.0 with
WinAVR Compiler results in Linker Error.
(Skipping Library libavrxxx.a, File not found).
QTouch Libraries
Release 5.0 are
build with Atmel
Studio6 Native
Toolchain Flavor.
Always use Native Toolchain Flavor
(Advanced Tab in Project properties)
setting in Atmel Studio6 for Building
QTouch Library Release.
The GCC example projects for QMatrix does not
compile the delay cycles
(QT_DELAY_CYCLES) above a value of 5
because of the preprocessor expansions.
Recommended to remove UL from
the preprocessor constants and in
the chain of macros used for
QT_DELAY_CYCLES. Valid for
QT_DELAY_CYCLES = 5,10,25,50.
Compiling QT600 project files throws These variables are available in 112 8207L-AT42-05/12
unused variable warning. the debug protocol for future use.
When using IAR workbench for ATSAM to
integrate the touch libraries, the linker
would generate a warning indicating:
Warning[Lp005]: placement includes a mix
of sections with content (example "ro data
section .data_init in xfiles.o(dl7M_tl_if.a)")
and sections without content (example "rw
data section .data in xfiles.o(dl7M_tl_if.a)")
Warning[Lp006]: placement includes a mix
of writable sections (example "rw data
section .data in xfiles.o(dl7M_tl_if.a)") and
non-writable sections (example "ro data
section .data_init in xfiles.o(dl7M_tl_if.a)")
This is because
we link the
library in RW
data section.
5.11Checklist
This section lists troubleshooting tips and common configuration tips.
Symptom Cause Action
Sensors do not go into detect or
have unknown results
Multiplexing pins
used by QTouch
libraries in your
design
Check the Pins used for QTouch or
QMatrix acquisition methods do not
overlap with the applications usage
of the ports
Signal values report arbitrary
values Stray capacitance
Check the sensor design and
minimize stray capacitance
interference in your design
Waveforms of charging /
discharging of channels do not
show up properly in oscilloscopes
JTAG ICE connected
to the board
Try disconnecting the JTAG ICE
completely from the kit
When using the example
applications, the debug values for
some of the channels does not
display appropriate values
JTAG Pins are
enabled in the target.
JTAG Pins are explicitly needs to
be disabled in the main.c file
/* disable JTAG pins */
MCUCR |= (1u << JTD);
MCUCR |= (1u << JTD)113
6 Device Specific Libraries
6.1 Introduction
This section provides an overview of the usage of Device specific QTouch Libraries. Device
Specific Libraries have been provided for special devices, which are not covered as part of
Generic Libraries.
6.2 Devices supported
The following devices are covered by the Device Specific QTouch Libraries.
1. AT32UC3L0, AT32UCL3U/L4U family devices.
2. ATtiny10, ATtiny20 and ATtiny40 devices.
6.3 QTouch Library for AT32UC3L devices
ATMEL QTouch Library for UC3L can be used for embedding capacitive touch buttons, sliders
and wheels functionality into UC3L application. The QTouch Library for UC3L uses the Capacitive
Touch Module (CAT) that senses touch on external capacitive touch sensors.
This Section describes the QTouch Library Application Programming Interface (API) for QMatrix
and QTouch method acquisition using the AT32UC3L devices.
6.3.1 Salient Features of QTouch Library for UC3L
6.3.1.1 QMatrix method sensor
• N Touch Channels formed by an X by Y matrix require (X+2Y+1) physical pins (when
using internal discharge mode), N=X*Y. Please refer Figure 37 for pin requirements in
different modes.
• 1 to 136 Touch Channels can be configured.
• Max X Lines = 17, Max Y Lines = 8.
• Button is formed using 1 Touch Channel.
• Slider is formed using 3 to 8 Touch Channels.
• Wheel is formed using 3 to 8 Touch Channels.
6.3.1.2 QTouch method sensor
• 2 Physical pins per Touch Channel.
• QTouch Sensors can be divided into two groups Group A and Group B.
• Each QTouch group can be configured with different properties.
• 1 to 17 Touch Channels can be configured.
• Button is formed using 1 Touch Channel.
• Slider is formed using 3 Touch Channels.114 8207L-AT42-05/12
• Wheel is formed using 3 Touch Channels.
6.3.1.3 Autonomous QTouch sensor
• A Single QTouch sensor that is capable of detecting touch or proximity without CPU
intervention.
• Allows proximity or activation detection in low-power sleep modes.
6.3.1.4 Additional Features
• Standalone QMatrix, QTouch Group A/B or Autonomous QTouch operation.
• Support for operation of two or more methods at the same time.
o Scenario 1: QMatrix and Autonomous QTouch method at the same time.
o Scenario 2: QTouch Group A, QTouch Group B & Autonomous QTouch at the
same time.
o Scenario 3: QMatrix, QTouch Group A/B and Autonomous QTouch at the same
time.
• Disable/Re-enable Sensors at any given time for reduced power consumption.
• Raw data acquisition mode without any post-processing of data.
• External synchronization to reduce 50 or 60 Hz mains interference.
• Spread spectrum sensor drive capability.
• QTouch Studio-Touch Analyzer support to fine tune touch implementation.
• IAR and GCC Tool chain support.
• MISRA Compliant, MISRAC 2004 Rule Set.
• Single Library for QMatrix, QTouch Group A/B and Autonomous QTouch methods.
6.3.2 Device variants supported for UC3L
Below is the list of different devices in AT32UC3L family that is supported by the QTouch library.
1. AT32UC3L016, AT32UC3L032, AT32UC3L064
2. ATUC64L3U, ATUC128L3U, ATUC256L3U (Studio 6 Support only.)
3. ATUC64L4U, ATUC128L4U, ATUC256L4U (Studio 6 Support only.)
For capacitive touch sensing module related information Refer to, “Capacitive touch module
(CAT)” of the datasheet.
6.3.3 Development tool support for UC3L
The QTouch libraries for AT32UC3L devices are supported for the following development tools.
Tool Version
IAR Embedded Workbench for Atmel AVR32.
IAR32 Compiler. 4.1
Atmel Studio 6. GCC Compiler 6.0
Table 8 Development tool support for UC3L QTouch Library115
6.3.4 Overview of QTouch Library API for UC3L
The diagram below captures the high level arrangement of the QTouch Library for UC3L API.
The QTouch Library for UC3L API can be used for Sensor configuration, Sensor Acquisition
parameter setting and Sensor Enable/Disable operations. Based on this input Sensor
configuration, the QTouch Library takes care of the initialization, configuration and acquisition
data capture operations using the CAT module. The UC3L CAT module interfaces with the
external capacitive touch sensors and is capable of performing QTouch and QMatrix method
acquisition. For an Overview of QMatrix and QTouch Capacitive Touch acquisition, refer Section
5.2.
The raw acquisition data from the CAT module is processed by the QTouch Library. The
Adjacent Key Suppression (AKS), Detect Integration mechanism, Drift compensation and
Automatic Recalibration components of the Touch Library aid in providing a robust Touch
performance. Once the raw acquisition data is processed, the individual Sensor Status and
Wheel/Slider position information is provided to the user by means of a measurement complete
callback operation.
Figure 35 Overview diagram of QTouch Library for UC3L116 8207L-AT42-05/12
6.3.5 Acquisition method support for UC3L
With the QTouch Library for UC3L, it is possible for a user to configure the following types of
Sensors.
• QMatrix method sensors.
• QTouch Group A method sensors.
• QTouch Group B method sensors.
• Autonomous QTouch sensor.
The QTouch Library for UC3L API has been arranged such that it is possible for the user
application either to use any of the above method Standalone or two or more methods combined
together. The Table below captures the different API available under each method. For normal
operation, it is only required to use the Regular API set for each method. By using only the
Regular API set, it is possible to achieve reduced code memory usage when using the QTouch
Library. The Helper API is provided for added flexibility to the user application.
Acquisition method Regular API Helper API
QMatrix method API
touch_qm_sensors_init
touch_qm_sensor_config
touch_qm_sensors_calibrate
touch_qm_sensors_start_acquisition
touch_event_dispatcher
touch_qm_sensor_update_config
touch_qm_sensor_get_config
touch_qm_channel_update_burstlen
touch_qm_update_global_param
touch_qm_get_global_param
touch_qm_get_libinfo
touch_qm_sensor_get_delta
touch_deinit
QTouch Group A/B
method API
(The first parameter to the
QTouch API, allows to
distinguish between QTouch
Group A and QTouch Group
B.)
touch_qt_sensors_init
touch_qt_sensor_config
touch_qt_sensors_calibrate
touch_qt_sensors_start_acquisition
touch_event_dispatcher
touch_qt_sensor_update_config
touch_qt_sensor_get_config
touch_qt_update_global_param
touch_qt_get_global_param
touch_qt_get_libinfo
touch_qt_sensor_get_delta
touch_qt _sensor_disable
touch_qt _sensor_reenable
touch_deinit
Autonomous QTouch API touch_at_sensor_init
touch_at_sensor_enable
touch_at_sensor_disable
touch_at_sensor_update_config
touch_at_sensor_get_config
touch_at_get_libinfo
touch_deinit
Table 9 Acquisition method specific API
6.3.6 API State machine for UC3L
The QTouch Library State machine diagram captures the different library States, Events that are
allowed in each State and Event transition from one State to the other. The QTouch Library
maintains the States of QMatrix, QTouch Group A and QTouch Group B methods independently.
This means that QMatrix can be in a state that is different from the state of QTouch Group A or B
and vice versa.
117
For the case of Autonomous QTouch, only the TOUCH_STATE_NULL and TOUCH_STATE_INIT
states apply in the State diagram.
• The touch_at_sensor_init event causes a transition from TOUCH_STATE_NULL to
TOUCH_STATE_INIT.
• The touch_deinit event causes a transition from TOUCH_STATE_INIT to
TOUCH_STATE_NULL.
Figure 36 State Diagram of QTouch Library for UC3L
6.3.7 QMatrix method sensor operation for UC3L
6.3.7.1 QMatrix method pin selection for UC3L
Please refer AT32UC3L datasheet Table 28-2 Pin Selection Guide and Table 3-1 GPIO
Controller Function multiplexing, for mapping between the QMatrix method pin name and the
GPIO pin. It is possible to configure a maximum of 17 X Lines and 8 Y-Yk pairs. The X Line X8
(PA16) cannot be used for the QMatrix method as it is required to use this pin for the ACREFN
function.
The CAT module provides an option to enable a nominal output resistance of 1kOhm on specific
CAT module pins during the burst phase. The Table below captures the different QMatrix method
pin wherein a Resistive Drive can be optionally enabled. The rows marked with Grey indicate
that Resistive Drive option is not available on that pin. By carefully choosing the QMatrix method
TOUCH_
STATE_INIT
TOUCH_
STATE_ NULL
TOUCH_
STATE_
READY
TOUCH_
STATE_BUSY
touch_xx_sensors_init
touch_xx_sensors_calibrate
touch_xx_sensor_config
touch_xx_sensor_get_config
touch_xx_get_global_param
touch_xx_get_libinfo
touch_xx_sensor_update_config
touch_xx_sensor_get_config
touch_xx_update_global_param
touch_xx_get_global_param
touch_xx_get_sensor_delta
touch_xx_get_libinfo
touch_xx_get_libinfo
QTouch Library for UC3L State Diagram
TOUCH_
STATE_
CALIBRATE
touch_deinit
touch_deinit
touch_deinit
touch_qm_channel_udpate_burstlen
touch_qt_sensor_disable
touch_qt_sensor_reenable
touch_qm_channel_udpate_burstlen
touch_qt_sensor_disable
touch_qt_sensor_reenable
touch_xx_sensor_update_config
touch_xx_sensor_get_config
touch_xx_update_global_param
touch_xx_get_global_param
touch_xx_get_libinfo
touch_xx_sensors_calibrate
touch_xx_sensors_start_acquisition
measure_complete_callback
(provide measured data and
touch status)
touch_deinit
xx = qm, qt
Sensor state machine for QMatrix
and QTouch GroupA/B118 8207L-AT42-05/12
X and Yk pins wherein Resistive Drive can be enabled, saving on external components is
possible.
Section 6.3.1.1 provides detail on the number of Pin and Touch channels required for different
QMatrix method sensor. The hardware arrangement for Wheel or Slider must be such that all
Touch channels corresponding to the Wheel or Slider belong to the same Yk Line.
Also, Section 6.3.11 indicates the various Pin Configuration options for the QTouch Library that
can be used to specify a user defined configuration.
CAT Module Pin Name QMatrix method Pin Name
CSA0 X0
CSB0 X1
CSA1 Y0
CSB1 YK0
CSA2 X2
CSB2 X3
CSA3 Y1
CSB3 YK1
CSA4 X4
CSB4 X5
CSA5 Y2
CSB5 YK2
CSA6 X6
CSB6 X7
CSA7 Y3
CSB7 YK3
CSA8 X8
CSB8 X9
CSA9 Y4
CSB9 YK4
CSA10 X10
CSB10 X11
CSA11 Y5
CSB11 YK5
CSA12 X12
CSB12 X13
CSA13 Y6
CSB13 YK6
CSA14 X14
CSB14 X15
CSA15 Y7
CSB15 YK7
CSA16 X16
CSB16 X17
Table 10 QMatrix Resistive drive pin option
(The rows marked with Grey indicate that Resistive Drive option is not available on that pin)
6.3.7.2 QMatrix method Schematic for UC3L
6.3.7.2.1 Internal Discharge mode
The CAT module provides an internal discharge arrangement for QMatrix method. When this
arrangement is used along with the Resistive drive capability, minimal external component is
required as shown in the case A of Figure 27. When the Resistive drive is option is not enabled,
it is recommended to use 1kOhm resistors on X and Yk Lines external to the UC3L device. This
hardware arrangement is shown in case B.119
6.3.7.2.2 External Discharge mode
When the External Discharge arrangement is used, a logic-level (DIS) pin is connected to an
external resistor (Rdis) that can be used to control the discharge of the Capacitors. A typical
value for Rdis is 100 kOhm. This value of Rdis will give a discharge current of approximately
1.1V/(100 kOhm) = 11 microAmp. The case C shows this arrangement. The Resistive drive
option on the X and Yk lines can be optionally enabled or disabled with this arrangement. When
the Resistive drive is option is not enabled, it is recommended to use 1kOhm resistors on X and
Yk Lines external to the UC3L device.
6.3.7.2.3 SMP Discharge Mode
When the SMP Discharge mode arrangement is used, a logic-level (SMP) pin is connected to the
capacitors through external high value resistors for the discharge of the capacitors. The case D
shows this arrangement. The Resistive drive option on the X and Yk lines can be optionally
enabled or disabled with this arrangement. When the Resistive drive is option is not enabled, it is
recommended to use 1kOhm resistors on X and Yk Lines external to the UC3L device.
6.3.7.2.4 VDIVEN Voltage Divider Enable option
The VDIV pin provides an option to make ACREFN a small positive voltage if required. The VDIV
pin is driven when the analog comparators are in use, and this signal can be used along with a
voltage divider arrangement to create a small positive offset on the ACREFN pin. The VDIVEN
option can be used optionally with any of the QMatrix modes discussed in the previous sections.
Typical values for Ra and Rb are Ra=8200 ohm and Rb = 50 ohm. Assuming a 3.3V I/O supply,
this will shift the comparator threshold by 3.3V*(Rb/(Ra+Rb)) which is 20 mV. The VDIVEN pin
option usage in the Internal Discharge mode scenario is shown in case E.
6.3.7.2.5 SYNC pin option
In order to prevent interference from the 50 or 60 Hz mains line the CAT can optionally trigger
QMatrix acquisition on the external SYNC input signal. The SYNC signal should be derived from
the mains line and the acquisition will trigger on a falling edge of this signal. The SYNC pin
option can be used with any of the QMatrix modes discussed in the previous sections. The
SYNC pin usage in the Internal Discharge mode scenario is shown in case F.
For QMatrix method SMP, DIS, VDIV and SYNC pin options discussed in this Section, Refer to
Section 6.3.15.2.13. 120 8207L-AT42-05/12
Figure 37 QMatrix method schematic
Atmel
AT32UC3L
Atmel
AT32UC3L
Atmel
AT32UC3L
Atmel
AT32UC3L
Atmel
AT32UC3L
Atmel
AT32UC3L
Sensors
X, Y
CAT CS0
Module
ACIFBACREFN
YmA
Y0A
Xn
X2
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
Typical Values:
CS:4.7nF
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
ACIFB-ACREFN: PA16 I/O pin
...
...
A. QMatrix Internal Discharge mode arrangement.
Resistive drive enabled on X and Yk Lines
Sensors
X, Y
CS0
CAT
Module
ACIFBACREFN
YmA
Y0A
Xn
RXn
X0
RX0
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
RXn
RX0
...
...
...
B. QMatrix Internal Discharge mode arrangement.
Resistive drive disabled on X and Yk Lines
Sensors
X, Y
CS0 CAT
Module
ACIFBACREFN
YmA
Y0A
Xn
X2
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
DIS
...
Rdis
C. QMatrix External Discharge mode arrangement.
Resistive drive enabled on X and Yk Lines
...
Sensors
X, Y
CS0
CAT
Module
ACIFBACREFN
YmA
Y0A
Xn
RXn
X0
RX0
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
RXn
RX0
RYB0 RYBm
SMP
...
...
...
D. QMatrix SMP Discharge mode arrangement.
Resistive drive disabled on X and Yk Lines
Sensors
X, Y
CS0
CAT
Module
ACIFBACREFN
YmA
Y0A
Xn
X2
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
...
...
VDIVEN
Ra
Rb
E. QMatrix Internal Discharge mode arrangement
with Volage Divider option enabled.
Resistive drive enabled on X and Yk Lines Sensors
X, Y
CS0
CAT
Module
ACIFBACREFN
YmA
Y0A
Xn
X2
Sensor
n, 0
Sensor
0, m
Sensor
n, m
Sensor
0, 0
CSm
YmB
Y0B
...
...
SYNC Synchronize
signal
F. QMatrix Internal Discharge mode arrangement
with External Sync option enabled.
Resistive drive enabled on X and Yk Lines
Typical Values:
CS:4.7nF
RX: 1kOhm
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
ACIFB-ACREFN: PA16 I/O pin
Typical Values:
CS:4.7nF
Rdis: 100kOhm
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
DIS: CAT-DIS IO pin
ACIFB-ACREFN: PA16 I/O pin
Typical Values:
CS:4.7nF
RX: 1kOhm
RYB: 1kOhm
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
SMP: CAT-SMP IO pin
ACIFB-ACREFN: PA16 I/O pin
Typical Values:
CS:4.7nF
Ra: 16500 Ohm
Rb: 50 Ohm
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
VDIVEN: CAT-VDIVEN IO pin
ACIFB-ACREFN: PA16 I/O pin
Typical Values:
CS:4.7nF
n - number of X Lines
m - number of Y Lines
I/O Pin requirements:
X: QMatrix method X Line
YA: QMatrix method Yk Line
YB: QMatrix method Y Line
SYNC: CAT-SYNC IO pin
ACIFB-ACREFN: PA16 I/O pin121
6.3.7.3 QMatrix method hardware resource requirement for UC3L
The clock for the CAT module, CLK_CAT, is generated by the Power Manager (PM). This clock is
turned on by default, and can be enabled and disabled in the PM. The user must ensure that
CLK_CAT is enabled before initializing the QTouch Library.
QMatrix operations also require the CAT generic clock, GCLK_CAT. This generic clock is
generated by the System Control Interface (SCIF), and is shared between the CAT and the
Analog Comparator Interface. The user must ensure that the GCLK_CAT is enabled in the SCIF
before using QMatrix functionality. For proper QMatrix operation, the frequency of GCLK_CAT
must be less than one fourth the frequency of CLK_CAT.
For QMatrix operation, the Analog comparators channels are used (using the ACIFB interface)
depending on the Y Lines enabled. See Note 4 in Section 6.3.7.4.
The QMatrix method acquisition using the CAT module requires two Peripheral DMA channels
that must be provided by the application.
6.3.7.4 QMatrix method Channel and Sensor numbering for UC3L
Sensor
4
Sensor
3
Sensor
2
Sensor
1
Ch 0
X0
X3
X2
X1
Yk0 Yk1 Yk2 Yk3
KEY
ROTOR/
SLIDER
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Ch 8
Ch 9
Ch 10
Ch 11
Ch 12
Ch 13
Ch 14
Ch 15
Sensor 0
Sensor 5
Sensor 6
Figure 38 QMatrix channel numbering for UC3L
The above figure represents a typical 4 X 4 matrix of QMatrix sensor arrangement along with the
channel numbers. The Channel numbering starts with Channel 0 (Ch0) and increase sequentially
from Ch0 to Ch15. Similarly the Sensor numbering starts with Sensor 0. The Channel number
signifies the order in which the QTouch Library stores the acquisition data in the memory.
Note: The touch_qm_sensor_config API must follow the above Channel and Sensor numbering
when configuring the Sensors.
6.3.7.5 QMatrix method API Flow for UC3L
For the QMatrix operation, the CAT_CLK and GCLK_CAT clocks must be setup appropriately as
a first step. The QMatrix and Common configuration parameters in the touch_config_at32uc3l.h
configuration must then be set up.122 8207L-AT42-05/12
Figure 39 QMatrix API Flow diagram for UC3L
touch_qm_sensors_init()
Configure multiple
QMatrix sensors
Using the init_clock() in main.c and clock.c files,
Set the CAT_CLK Clock to appropriate value.
Set the GCLK_CAT Clock to appropriate value.
touch_qm_sensors_config()
Using the touch_config_at32uc3l.h configuration file,
Set DEF_TOUCH_QMATRIX = 1.
Set all QM_xx and TOUCH_xx macros to appropriate values.
(This includes 2 peripheral DMA Channels required for QMatrix operation.)
In the main.c file,
Set appropriate qm_burst_length[] values corresponding to all Touch channels .
Set the desired measurement_period_ms for Touch measurement.
touch_qm_sensors_calibrate()
touch_event_dispatcher()
touch_qm_sensors_start_
acquisition(NORMAL_ACQ_MODE)
Call in loop
time_to_
measure_touch
filter_callback(), if enabled
measure_complete_callback(),
measured data and Touch Status
Host Application code123
The burst length values of each Touch channel must be specified using the qm_burst_length[]
array in the main.c file. The burst length must be specified in the same order of Touch Channel
numbering.
The touch_qm_sensors_init API initializes the QTouch Library as well as the CAT module and
does the QMatrix method specific pin, register and Global Sensor configuration. The
touch_qm_sensor_config API is used to configure individual sensor. The Sensor specific
configuration parameter can be provided as input to this API.
The touch_qm_sensors_calibrate API is used to calibrate all the configured sensors thereby
preparing the sensors for acquisition. The touch_qm_sensors_start_acquisition API initiates a
QMatrix method measurement on all the configured Sensors. This API takes the peripheral DMA
channels as an input. When a filter_callback function is enabled, the touch_event_dispatcher
function calls the filter_callback function as soon as the raw acquisition data from the Sensors is
available. The user can now optionally apply any filtering routine on the raw acquisition data
before the QTouch Library does any processing on this data. (For an overview of Filter callback
usage, refer Section 5.6.6.4 Example code). Once the QTouch Library has finished processing
the acquisition data from Sensors, the touch_event_dispatcher function calls the
measure_complete_callback function indicating the end of a single Touch measurement
operation. The measure_complete_callback provides the measured data and Touch status
information. The measured data is available in the same order of Touch Channel numbering.
Note 1: The Host Application code can execute once a QMatrix acquisition is initiated with the
touch_qm_sensors_start_acqusition API. Care must be taken in the Host Application such that
the touch_event_dispatcher function is called frequently in order to process the acquired data.
For a single Touch measurement operation (between a touch_qm_sensors_start_acquisition API
call and the measure_complete_callback function being called), the touch_event_dispatcher
function may execute multiple times in order to resolve the Touch status of Sensors. Failing to
call the touch_event_dispatcher frequently can adversely impact the Touch Sensitivity.
Note 2: Once the Touch Library has been initialized for QMatrix method using the
touch_qm_sensors_init API, a new qm_burst_length[x] value of a Touch channel must be
updated only using the touch_qm_channel_update_burstlen API. It is recommended to have
qm_burst_length array as global variable as the Touch Library updates this array when the
touch_qm_channel_update_burstlen API is called.
Note 3: QMatrix burst length setting recommendation.
For a given X Line, the burst length value of ALL enabled Y Lines MUST be the same or set to
0x01(disabled). For example, the burst length value corresponding to (X0,Y1),(X0,Y2)...(X0,Yn)
must be the same. In case of a scenario, wherein it is required to have a different a burst length,
then the following option can be tried out - Enable the 1k ohm drive resistors on all the enabled Y
lines by setting the corresponding bit in the CSARES register.
Note 4: For QMatrix operation, the Analog comparators channels are used (using the ACIFB
interface) depending on the Y Lines enabled. For example, when Y lines Y2 and Y7 are enabled
the Analog comparator channels 2 and 7 are used by the CAT module for QMatrix operation.
The user can uses the rest of the Analog comparator channels in the main application. The
QTouch Library enables the ACIFB using the Control register (if not already enabled by the main
application) when the touch_qm_sensors_init API is called.124 8207L-AT42-05/12
6.3.7.6 QMatrix method Disable and Re-enable Sensor for UC3L
The touch_qm_channel_update_burstlen API can be used for Disabling and Re-enabling of
QMatrix Sensors. In order to Disable a sensor, the QMatrix burst length value of all the Touch
Channels corresponding to the Sensor must be set to 1. For Example, when a Wheel or Slider is
composed of 4 Touch Channels, the touch_qm_channel_update_burstlen API should be used to
set the burst length of all the 4 Touch Channels to 1. For the case of a Button,
touch_qm_channel_update_burstlen API should be used to set burst length of the corresponding
single Touch Channel of the Button to 1. Similarly, when re-enabling a Sensor, appropriate burst
length must be set to all the Touch channels corresponding to the Sensor.
When a QMatrix Sensor is Disabled or re-enabled, it is mandatory to force Calibration on all
Sensors. The Calibration of all Sensors is done using the touch_qm_sensors_calibrate API.
Note: When disabling a Wheel or Slider, care must be taken to set the burst length of all the
Touch channels corresponding to the Wheel or Slider to 1. If any of the Touch channels are
missed out, it may result in undesired behavior of the Wheel or Slider. Similarly when re-enabling
a Wheel or Slider, burst length of all the Touch channels corresponding to the Wheel or Slider
must be set to an appropriate value. If any of the Touch Channels are left disabled with a burst
length value 1, it may result in undesired behavior of Wheel or Slider.
6.3.8 QTouch Group A/B method sensor operation for UC3L
6.3.8.1 QTouch Group A/B method pin selection for UC3L
Please refer AT32UC3L datasheet Table 28-2 Pin Selection Guide and Table 3-1 GPIO
Controller Function multiplexing, for mapping between the QTouch method pin name
(SNS/SNSK) and the GPIO pin. The CAT module provides an option to enable a nominal output
resistance of 1kOhm on specific CAT module pins during the burst phase. The Table below
captures the different QTouch method pin wherein a Resistive Drive can be optionally enabled.
The rows marked with Grey indicate that Resistive Drive option is not available on that pin. By
carefully choosing the QTouch method SNSK pins wherein Resistive Drive can be enabled,
saving on external components is possible. Section 6.3.1.2 provides detail on the number of Pin
and Touch channels required for different QTouch method sensor. Also, Section 6.3.11 indicates
the various Pin Configuration options for the QTouch Library that can be used to specify a user
defined configuration. 125
CAT Module Pin Name QTouch method Pin Name
CSA0 SNS0
CSB0 SNSK0
CSA1 SNS1
CSB1 SNSK1
CSA2 SNS2
CSB2 SNSK2
CSA3 SNS3
CSB3 SNSK3
CSA4 SNS4
CSB4 SNSK4
CSA5 SNS5
CSB5 SNSK5
CSA6 SNS6
CSB6 SNSK6
CSA7 SNS7
CSB7 SNSK7
CSA8 SNS8
CSB8 SNSK8
CSA9 SNS9
CSB9 SNSK9
CSA10 SNS10
CSB10 SNSK10
CSA11 SNS11
CSB11 SNSK11
CSA12 SNS12
CSB12 SNSK12
CSA13 SNS13
CSB13 SNSK13
CSA14 SNS14
CSB14 SNSK14
CSA15 SNS15
CSB15 SNSK15
CSA16 SNS16
CSB16 SNSK16
Table 11 QTouch Resistive drive pin option
(The rows marked with Grey indicate that Resistive Drive option is not available on that pin.)
6.3.8.2 QTouch Group A/B method Schematic for UC3L
6.3.8.2.1 Resistive Drive option
The cases A and B of the Figure provide the schematic arrangement of QTouch Group A/B and
Autonomous QTouch Sensors. In option A, Resistive drive is enabled on SNSK line. In case B,
Resistive drive is disabled on the SNSK line and in this case, it is recommended to use 1kOhm
resistors on SNSK Line external to the UC3L device.
6.3.8.2.2 SYNC pin option
In order to prevent interference from the 50 or 60 Hz mains line the CAT can optionally trigger
QTouch Group A/B and Autonomous QTouch acquisition on the external SYNC input signal. The
SYNC signal should be derived from the mains line and the acquisition will trigger on a falling
edge of this signal. The SYNC pin usage in the Internal Discharge mode scenario is shown in
case C. For QTouch method SYNC pin options Refer to Section 6.3.15.2.13.126 8207L-AT42-05/12
Figure 40 QTouch Group A/B and Autonomous QTouch schematic arrangement
6.3.8.3 QTouch Group A/B method hardware resource requirement for UC3L
The clock for the CAT module, CLK_CAT, is generated by the Power Manager (PM). This clock is
turned on by default, and can be enabled and disabled in the PM. The user must ensure that
CLK_CAT is enabled before initializing the QTouch Library.
The QTouch method acquisition using the CAT module requires one Peripheral DMA channel
that must be provided by the application.
Atmel
AT32UC3L
CAT
Module
A. QTouch Group A/B and Autonomous QTouch arrangement.
Resistive drive enabled on SNSK Line.
Sensor
Cs
Typical Values:
Cs: 22nF
Pin requirements:
SNS: CAT QTouch method I/O pin
SNSK: CAT QTouch method I/O pin
SNSK
SNS
Atmel
AT32UC3L
CAT
Module
Sensor
Cs
Typical Values:
Cs: 22nF
Pin requirements:
SNS: CAT QTouch method I/O pin
SNSK: CAT QTouch method I/O pin
SYNC: CAT-SYNC I/O pin
SNSK
SNS
C. QTouch Group A/B and Autonomous QTouch arrangement.
Resistive drive enabled on SNSK Line.
External Synchronization enabled.
Sync
signal
SYNC
Atmel
AT32UC3L
CAT
Module
Sensor
Cs
Typical Values:
Cs: 22nF, Rs:1kOhm
Pin requirements:
SNS: CAT QTouch method I/O pin
SNSK: CAT QTouch method I/O pin
SNSK
SNS
Rs
B. QTouch Group A/B and Autonomous QTouch arrangement.
Resistive drive disabled on SNSK Line.127
6.3.8.4 QTouch Group A/B method Channel and Sensor numbering for UC3L
Figure 41 QTouch method Channel/Sensor numbering
The above Figure represents an example 4 Channel QTouch sensor arrangement along with the
channel numbers. The Channel numbering starts with the lowest SNS-SNSK QTouch method
pair number (SNS2-SNSK2 being the least in this case) and increases as the SNS-SNSK pair
number increases. Similarly the Sensor numbering starts with Sensor 0. The Channel number
signifies the order in which the QTouch Library stores the acquisition data in the memory.
Figure 42 QTouch method Channel/Sensor numbering when Group A and B are used
together
When both QTouch Group A and QTouch Group B method are used at the same time, the SNSSNSK
pairs associated with the individual group alone must be taken into consideration when
determining the Channel number.
Note: The touch_qt_sensor_config API must follow the above Channel and Sensor numbering
when configuring the Sensors.
channel 0
Sensor 0
Sensor 1
ATMEL
AT32UC3L
SNSK2
SNS2
SNSK3
SNS3
SNSK5
SNS5
SNSK9
SNS9
channel 1
channel 2
channel 3
QTouch Grp A Channel 0
QTouch Grp A
Sensor 0
QTouch Grp B
Sensor 0
ATMEL
AT32UC3L
SNSK2
SNS2
SNSK3
SNS3
SNSK5
SNS5
SNSK6
SNS6
QTouch Grp A
Sensor 1
SNSK7
SNS7
SNSK9
SNS9
QTouch Grp B
Sensor 1
QTouch Grp A Channel 1
QTouch Grp A Channel 2
QTouch Grp B Channel 0
QTouch Grp A Channel 3
QTouch Grp B Channel 1 128 8207L-AT42-05/12
6.3.8.5 QTouch Group A/B method API Flow for UC3L
For the QTouch operation, the CAT_CLK must be setup appropriately as a first step. Depending
on QTouch Group that need to be used, the QTouch Group A, QTouch Group B and Common
configuration parameters in the touch_config_at32uc3l.h configuration must then be set up.
The first input argument to the QTouch API, TOUCH_QT_GRP_A or TOUCH_QT_GRP_B
indicates if the QTouch API must perform the necessary operation on Group A Sensors or Group
B Sensors. The touch_qt_sensors_init API initializes the QTouch Library as well as the CAT
module and does the QTouch method specific pin, register and Global Sensor configuration. The
touch_qt_sensor_config API is used to configure individual sensor. The Sensor specific
configuration parameter can be provided as input to this API.
The touch_qt_sensors_calibrate API is used to calibrate all the configured sensors thereby
preparing the sensors for acquisition. The touch_qt_sensors_start_acquisition API initiates a
QTouch method measurement on all the configured Sensors (corresponding to the input Touch
Group A or B). This API takes the peripheral DMA channels as an input. When a filter_callback
function is enabled, the touch_event_dispatcher function calls the filter_callback function as soon
as the raw acquisition data from the Sensors is available. The user can now optionally apply any
filtering routine on the raw acquisition data before the QTouch Library does any processing on
this data. (For an overview of Filter callback usage, refer Section 5.6.6.4 Example code). Once
the QTouch Library has finished processing the acquisition data from Sensors, the
touch_event_dispatcher function calls the measure_complete_callback function indicating the end
of a single Touch measurement operation. The measure_complete_callback provides the
measured data and Touch status information. The measured data is available in the same order
of Touch Channel numbering. Separate Filter and Measure complete callback functions must be
provided for Group A and Group B Sensors.
Note: The Host Application code can execute once a QTouch acquisition is initiated with the
touch_qt_sensors_start_acqusition API. Care must be taken in the Host Application such that the
touch_event_dispatcher function is called frequently in order to process the acquired data. For a
single Touch measurement operation (between a touch_qt_sensors_start_acquisition API call
and the measure_complete_callback function being called), the touch_event_dispatcher function
may execute multiple times in order to resolve the Touch status of Sensors. Failing to call the
touch_event_dispatcher frequently can adversely impact the Touch Sensitivity. 129
Figure 43 QTouch method API Flow diagram
touch_qt_sensors_init()
Configure multiple
QTouch sensors
Using the init_clock() in main.c and clock.c files,
Set the CAT_CLK Clock to appropriate value.
touch_qt_sensors_config()
Using the touch_config_at32uc3l.h configuration file,
Set DEF_TOUCH_QTOUCH_GRP_A = 1, if QTouch Group A is to be used.
Set DEF_TOUCH_QTOUCH_GRP_B = 1, if QTouch Group B is to be used.
Set all QTA_xx (if Group A is enabled) to appropriate values.
Set all QTB_xx (if Group B is enabled) to appropriate values.
Set all TOUCH_xx macros to appropriate values.
(This includes 1 peripheral DMA Channels required for QTouch operation.)
In the main.c file,
Set the desired measurement_period_ms for Touch measurement.
The API Sequence below must be repeated for Group A and Group B when both the
Groups are used at the same time. The first argument to the API
TOUCH_QT_GRP_A or TOUCH_QT_GRP_B distinguishes between Group A and
Group B operations. Separate Filter and Measurement complete callback functions
must be provided for Group A and Group B Sensors.
touch_qt_sensors_calibrate()
touch_event_dispatcher()
touch_qt_sensors_start_
acquisition(NORMAL_ACQ_MODE)
Call in loop
time_to_
measure_touch
filter_callback(), if enabled
measure_complete_callback(),
measured data and Touch Status
Host Application code130 8207L-AT42-05/12
6.3.8.6 QTouch Group A/B method Disable and Re-enable Sensor for UC3L
The touch_qt_sensor_disable and touch_qt_sensor_reenable API can be used for Disabling and
Re-enabling of QTouch Group A and Group B Sensors. In order to Disable or re-enable a
sensor, the API must be called with the corresponding sensor_id. Disabling a Sensor disables
the measurement process on all the Touch Channels corresponding to Sensor.
When a QTouch Sensor is Disabled or re-enabled, it is mandatory to force Calibration on all
Sensors. The Calibration of all Sensors is done using the touch_qt_sensors_calibrate API.
6.3.9 Autonomous QTouch sensor operation for UC3L
6.3.9.1 Autonomous QTouch Sensor pin selection for UC3L
The Autonomous QTouch Sensor pin selection is similar to selection of pin for QTouch Group A/B
as indicated in Section 6.3.8.1. Any one SNS-SNSK pair between SNS0-SNSK0 and SNS16-
SNSK16 can be chosen to function as an Autonomous QTouch sensor.
6.3.9.2 Autonomous QTouch sensor Schematic for UC3L
The Autonomous QTouch Sensor Sensor schematic is similar QTouch schematic as indicated in
Section 6.3.8.2.
6.3.9.3 Autonomous QTouch method hardware resource requirement for UC3L
The clock for the CAT module, CLK_CAT, is generated by the Power Manager (PM). This clock is
turned on by default, and can be enabled and disabled in the PM. The user must ensure that
CLK_CAT is enabled before initializing the QTouch Library for Autonomous QTouch.
For the Autonomous QTouch Sensor, the complete detection algorithm is implemented within the
CAT module. This allows detection of proximity or touch without CPU intervention. Since the
Autonomous QTouch Sensor operates without software interaction, this Sensor can be used to
wakeup from sleep modes when activated. The Autonomous QTouch Status change interrupt
can be used to wakeup from any of the Sleep modes shown in the Table. The ‘Static’ Sleep
mode being the deepest possible Sleep mode from which a wake up from Sleep is possible using
the Autonomous QTouch. Both an IN_TOUCH status change and OUT_OF_TOUCH status
change indication is available when using Autonomous QTouch.
The Autonomous QTouch method acquisition using the CAT module does not require any
Peripheral DMA channel for operation.
Sleep
Mode CPU HSB PBA,B
GCLK
Clock
sources Osc32 RCSYS BOD &
Bandgap
Voltage
Regulator
Idle Stop Run Run Run Run Run On Full power
Frozen Stop Stop Run Run Run Run On Full power
Standby Stop Stop Stop Run Run Run On Full power
Stop Stop Stop Stop Stop Run Run On Low power
DeepStop Stop Stop Stop Stop Run Run Off Low power
Static Stop Stop Stop Stop Run Stop Off Low power
Table 12 Sleep mode support for Autonomous QTouch131
6.3.9.4 Autonomous QTouch Sensor API Flow for UC3L
For the Autonomous QTouch operation, the CAT_CLK must be setup appropriately as a first step.
The Autonomous QTouch and Common configuration parameters in the touch_config_at32uc3l.h
configuration must then be set up.
The touch_at_sensors_init API initializes the QTouch Library as well as the CAT module for the
Autonomous QTouch sensor related pin, register and Global Sensor configuration. The
Autonomous QTouch Sensor can be enabled at any time by the Host Application. Once the
Autonomous QTouch Sensor is enabled, the CAT module performs measurements on this sensor
continuously to detect a Touch Status. When an IN_TOUCH or OUT_OF_TOUCH status is
detected, the QTouch Library calls the touch_at_status_change_interrupt_callback function to
indicate the status to the Host application. It is possible to enable and disable Autonomous
QTouch sensor multiple times in the Host application by using the touch_at_sensor_enable and
touch_at_sensor_disable API.
Figure 44 Autonomous QTouch API Flow diagram
6.3.9.5 Autonomous QTouch method Enable and Disable Sensor for UC3L
The touch_at_sensor_enable and touch_at_sensor_disable API can be used for Enabling and
Disabling and the Autonomous QTouch Sensor. Once the Autonomous QTouch sensor is
enabled, the CAT module performs continuous Touch Measurements on the Sensor in order to
detect the Touch Status.
touch_at_sensor_init()
Using the init_clock() in main.c and clock.c files,
Set the CAT_CLK Clock to appropriate value.
touch_at_sensor_enable()
Using the touch_config_at32uc3l.h configuration file,
Set DEF_TOUCH_AUTONOMOUS_QTOUCH = 1.
Set all AT_xx and TOUCH_xx macros to appropriate values.
touch_at_status_change_interrupt_callback(),
Autonomous QTouch Status
touch_at_sensor_disable()
Disable Autonomous
QTouch Sensor if required
The callback is called as long
as Autonomous QTouch
sensor is not disabled
Re-enable Autonomous
QTouch Sensor if required132 8207L-AT42-05/12
6.3.10 Raw acquisition mode support for UC3L
The QTouch Library Raw acquisition mode can be used with QMatrix, QTouch Group A and
QTouch Group B methods. When raw data acquisition mode is used, once the raw acquisition
data is available from the CAT module for all the sensors, the measure_complete_callback
function is immediately called with acquisition data (channel_signals). The channel_references,
sensor_states and rotor_slider_values data are not updated by the Touch Library in this mode.
Figure 45 Raw acquisition mode API Flow diagram
touch_xx_sensors_init()
Configure multiple
sensors
touch_xx_sensors_config()
touch_xx_sensors_calibrate()
touch_event_dispatcher()
touch_xx_sensors_start_
acquisition(RAW_ACQ_MODE)
Call in loop
time_to_
measure_touch
measure_complete_callback(),
Raw acquisition data.
Host Application code133
6.3.11 Library Configuration parameters for UC3L
The QTouch Library for UC3L provides a single configuration header file touch_config_at32uc3l.h
file for setting the various configuration parameters for each method. The different configuration
parameters corresponding to QMatrix, QTouch Group A/B and Autononmous QTouch sensors
are listed in the Table below.
Paramete
r
QMatrix QTouch Group A/B Autonomous
QTouch
Sensor
Configuration
QM_NUM_X_LINES
QM_NUM_Y_LINES
QM_NUM_SENSORS
QM_NUM_ROTORS_SLIDERS
QTx_NUM_SENSORS
QTx_NUM_ROTORS_SLIDERS None
Pin
Configuration QM_X_PINS_SELECTED
QM_Y_PAIRS_SELECTED
QM_SMP_DIS_PIN_OPTION
QM_VDIV_PIN_OPTION
QTx_SP_SELECTED AT_SP_SELECTED
Clock and
Register
Configuration
QM_GCLK_CAT_DIV
QM_CAT_CLK_DIV
QM_CHLEN
QM_SELEN
QM_CXDILEN
QM_DILEN
QM_DISHIFT
QM_MAX_ACQ_COUNT
QM_CONSEN
QM_INTREFSEL
QM_INTVREFSEL
QM_ENABLE_SPREAD_SPECTRU
M
QM_ENABLE_EXTERNAL_SYNC
QM_SYNC_TIM
QTx_CAT_CLK_DIV
QTx_CHLEN
QTx_SELEN
QTx_DILEN
QTx_DISHIFT
QTx_MAX_ACQ_COUNT
QTx_ENABLE_SPREAD_SPECTRU
M
QTx_ENABLE_EXTERNAL_SYNC
AT_CAT_CLK_DIV
AT_CHLEN
AT_SELEN
AT_DILEN
AT_DISHIFT
AT_MAX_ACQ_COUN
T
AT_ENABLE_SPREAD
_ SPECTRUM
AT_ENABLE_
EXTERNAL_SYNC
AT_FILTER
AT_OUTSENS
AT_SENSE
AT_PTHR
AT_PDRIFT
AT_NDRIFT
Peripheral
DMA
Channel
Configuration
QM_DMA_CHANNEL_0
QM_DMA_CHANNEL_1 QTx_DMA_CHANNEL_0 None
Global
acquisition
parameter
Configuration
QM_DI
QM_NEG_DRIFT_RATE
QM_POS_DRIFT_RATE
QM_MAX_ON_DURATION
QM_DRIFT_HOLD_TIME
QM_POS_ RECAL_DELAY
QM_RECAL_THRESHOLD
QTx_DI
QTx_NEG_DRIFT_RATE
QTx_POS_DRIFT_RATE
QTx_MAX_ON_DURATION
QTx_DRIFT_HOLD_TIME
QTx_ POS_RECAL_DELAY
QTx_RECAL_THRESHOLD
None
Callback
Function
Configuration
QM_FILTER_CALLBACK QTx_FILTER_CALLBACK None
Common
Configuration
Options
TOUCH_SYNC_PIN_OPTION, TOUCH_SPREAD_SPECTRUM_MAX_DEV,
TOUCH_CSARES, TOUCH_CSBRES
Table 13 QTouch Library for UC3L Configuration parameters134 8207L-AT42-05/12
For an overview of the Global acquisition configuration parameters and Sensor specific
parameters, refer Section 5.3 and Section 5.4. The detailed information on other parameters is
available in the configuration header file. For QMatrix method Design guidelines regarding
Sensor parameters refer Section 5.6.7.3.
6.3.12 Example projects for QTouch Library for UC3L
6.3.12.1 Example Project usage
The GNU Example projects can be used along with Atmel Studio 6.
Figure 46 GNU Example project usage with AVR32 Studio
The IAR Example Projects can be used with IAR Embedded Workbench for AVR32 v4.1
Figure 47 IAR Example project usage with IAR Embedded Workbench for AVR32135
6.3.12.2 QMatrix Example Project
The QMatrix method GNU and IAR Example projects can be found in the following path.
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\uc3l_gnu_qm_ek_example and
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\uc3l_iar_qm_ek_example
The QMatrix Example projects demonstrate the QMatrix operation on the UC3L Evaluation Kit
(Rev 2). QMatrix SMP discharge mode hardware arrangement is used for the UC3L Evaluation
Kit with 6 X Lines and 2 Y Lines. Using the 12 Touch Channels (6x2), 6 Touch Sensors are
formed that include a Rotor (that uses six Touch Channels) and 5 keys (each using one Touch
channel).
The Example projects demonstrate the QMatrix measured data and Touch Status usage using
the LED Demo application. The onboard LED0, LED1, LED2 and LED3 are set when the Touch
Position of the Rotor position varies from 0 to 255. By Touching the up key (^), left key (<),
play/pause key (>/||) and right key (>), the LED0, LED1, LED2 and LED3 can be individually
cleared. When the down key (v) is touched, it clears all LEDs.
Additionally QMatrix Example projects are also available for QT600 and STK600 boards.
6.3.12.3 QTouch Group A Example Project
The QTouch Group A method GNU and IAR Example projects can be found in the following path.
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\uc3l_gnu_qt_grp_a_example and
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\uc3l_iar_qt_grp_a_example
The QTouch Group A Example projects demonstrate the QTouch method API usage with a
Rotor, Slider and two keys Sensor configuration.
6.3.12.4 Autonomous QTouch Example Project
The Autonomous QTouch Sensor GNU and IAR Example projects can be found in the following
path.
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\
uc3l_gnu_autonomous_qt_example and
\Device_Specific_Libraries\32bit_AVR\UCxx\example_projects\
uc3l_iar_autonomous_qt_example
The Autonomous QTouch Example projects demonstrate the Autonomous QTouch Sensor API
usage. The Example projects also demonstrate wake up from Sleep mode using the
Asynchronous Timer peripheral event.
Note 1: The Example Projects also support relaying the Touch Sensor debug information to the
“QTouch Studio – Touch Analyzer” PC Software. The QTouch Studio can also be used for
setting the Sensor and Global configuration parameters of the QTouch Library at run-time.
The QTouch Studio can be downloaded from the following path.
The QDebug two-way debug protocol used by the Example project to communicate (transmit or
receive touch debug data) with the QTouch Studio can be found in the following installation path.
http://www.atmel.com/products/touchsoftware/qtouchsuite.asp?family_id=702
\Device_Specific_Libraries\32bit_AVR\UCxx\qdebug136 8207L-AT42-05/12
• For the UC3L Evaluation kit (uc3l_xx_qm_ek_example Example project) to connect with
the QTouch Studio using the USB interface, the UC3B MCU on the UC3L Evaluation kit
must be Flashed with ISP and Program binaries. The procedure to flash the binaries is
available in the readme note in the following path.
\Device_Specific_Libraries\32bit_AVR\UC3L\example_projects\uc3l_gnu_qm_ek_exampl
e\ uc3b\readme.txt or
\Device_Specific_Libraries\32bit_AVR\UC3L\example_projects\uc3l_iar_qm_ek_example
\ uc3b\readme.txt
• For the case of QTouch Group A and Autonomous QTouch Example projects, the
‘QT600-USB Bridge’ board can be use to capture the QDebug debug data in the QTouch
Studio.
Note 2: In order to flash the generated elf binary file for GNU and IAR, the following command
can be used from the Command Line.
avr32program --part UC3L064 program -finternal@0x80000000 -e --run -R -cint
uc3l_gnu_qm_ek_example.elf
6.3.13 Code and Data Memory requirements for UC3L
6.3.13.1 QMatrix method memory requirement
The Table below captures the Typical Code & Data Memory requirement for the QTouch Library
when QMatrix method is used standalone.
In addition to the Data memory captured in the Table, the QMatrix method requires additional
Data Memory that must be provided to the Touch Library for storing the Signals, References,
Sensor information and Touch status. This data memory is provided by the Host Application to
the QTouch Library as QMatrix data block. The size of this Data memory block depends on the
Number of Sensors and the Number of Wheel or Slider configured. The
PRIV_QM_DATA_BLK_SIZE macro in touch_api_at32uc3l.h calculates the size of this data
memory block. For example, for the UC3L Evaluation kit Rev2 that has 6 Sensors including 1
Wheel and 5 Buttons, the QMatrix data block memory size is 236 bytes.
Library Typical Code
with Keys Only
Typical Code when
one or more
Wheel/Sliders is
used
Typical
Data
Memory
libuc3l-qtouch-iar.r82 5882 7296 278
libuc3l-qtouch-gnu.a 6228 8080 278
Table 14 Typical Code and Data memory for Standalone QMatrix operation
Note: This Typical Code memory usage is achieved when only QMatrix Regular API is used in
the application. Usage of QMatrix Helper API would consume additional Code memory. Also,
the Code and Data memory indicated in the Table do not account for Example QMatrix
application.
6.3.13.2 QTouch Group A/B method memory requirement
The Table below captures the Typical Code & Data Memory requirement for the QTouch Library
when QTouch Group A or QTouch Group B Sensor is used standalone. (Additional Data memory
will be required when both Group A and Group B are used at the same time.)
In addition to the Data memory captured in the Table, the QTouch Group A/B method requires
additional Data Memory that must be provided to the Touch Library for storing the Signals, 137
References, Sensor information and Touch status. This data memory is provided by the Host
Application to the QTouch Library as QTouch data block. The size of this Data memory block
depends on the Number of Sensors and the Number of Wheel or Slider configured. Refer
PRIV_QTx_DATA_BLK_SIZE macro in touch_api_at32uc3l.h. For example, when 6 Sensors are
used that include 1 Wheel, 1 Slider and 2 Button, the QTouch GroupA/B data block memory size
is 184 bytes.
Library Typical Code
with Keys Only
Typical Code when
one or more
Wheel/Sliders is
used
Typical
Data
Memory
libuc3l-qtouch-iar.r82 5198 6450 358
libuc3l-qtouch-gnu.a 5290 6774 358
Table 15 Typical Code and Data memory for Standalone QTouch Group A/B operation
Note: This Typical Code memory usage is achieved when only the QTouch Group A/B Regular
API is used in the application. Usage of QTouch Group A/B Helper API would consume
additional Code memory. Also, the Code and Data memory indicated in the Table do not account
for Example QTouch application.
6.3.13.3 Autonomous QTouch memory requirement
The Table below captures the Typical Code & Data Memory requirement for the QTouch Library
when Autonomous Touch Sensor is used standalone.
Library Typical Code with
Keys Only
Typical Data
Memory
libuc3l-qtouch-iar.r82 1184 22
libuc3l-qtouch-gnu.a 966 16
Table 16 Minimum Code and Data for Standalone Autonomous QTouch sensor
Note: This Typical Code memory usage is achieved when only the Autonomous QTouch Regular
API is used in the application. Usage of Autonomous QTouch Helper API would consume
additional Code memory. Also, the Code and Data memory indicated in the Table do not account
for Example Autonomous QTouch application.
6.3.14 Public header files of QTouch Library for UC3L
Following are the public header files which need to be included in user’s application and these
have the type definitions and function prototypes of the APIs listed in the following sections
1. touch_api_at32uc3l.h - QTouch Library API and Data structures file.
2. touch_config_at32uc3l.h - QTouch Library configuration file.
6.3.15 Type Definitions and enumerations used in the library
6.3.15.1 Typedefs
This section lists the type definitions used in the library.
Typedef Notes
uint8_t unsigned 8-bit integer.
int8_t signed 8 bit integer.
uint16_t unsigned 16-bit integer.
int16_t signed 16-bit integer.138 8207L-AT42-05/12
uint32_t unsigned 32 bit integer.
int32_t signed 32 bit integer.
channel_t unsigned 8 bit integer that represents the channel number, starts from 0.
threshold_t unsigned 8 bit integer to set sensor detection threshold.
sensor_id_t unsigned 8 bit integer that represents the sensor ID, starts from 0.
touch_time_t unsigned 16 bit integer that represents current time maintained by the
library.
touch_bl_t unsigned 8 bit integer that represents the burst length of a QMatrix
channel.
touch_delta_t signed 16 bit integer that represents the delta value of a channel.
touch_acq_status_t unsigned 16 bit Status of Touch measurement.
touch_qt_grp_t unsigned 8 bit QTouch Group type.
touch_qt_dma_t unsigned 8 bit QTouch Group A/ Group B DMA channel type..
6.3.15.1.1 touch_acq_status_t
uint16_t touch_acq_status_t
Use Indicates the result of the last acquisition & processing for a specific touch
acquisition method.
Values Bitmask Comment
TOUCH_NO_ACTIVITY 0x0000u No Touch activity.
TOUCH_IN_DETECT 0x0001u At least one Touch channel is in detect.
TOUCH_STATUS_CHANGE 0x0002u Status change in at least one channel.
TOUCH_ROTOR_SLIDER_POS_CHANGE 0x0004u At least one rotor or slider has changed
position.
TOUCH_CHANNEL_REF_CHANGE 0x0008u Reference values of at least one of the
channel has changed.
TOUCH_BURST_AGAIN 0x0100u Indicates that reburst is required to
resolve Filtering or Calibration state.
TOUCH_RESOLVE_CAL 0x0200u Indicates that reburst is needed to
resolve Calibration.
TOUCH_RESOLVE_FILTERIN 0x0400u Indicates that reburst is needed to
resolve Filtering.
TOUCH_RESOLVE_DI 0x0800u Indicates that reburst is needed to
resolve Detect Integration.
TOUCH_RESOLVE_POS_RECAL 0x1000u Indicates that reburst is needed to
resolve Recalibration.
6.3.15.1.2 touch_qt_grp_t
uint8_t touch_qt_grp_t
Use QTouch Group type.
Values Value Comment
TOUCH_QT_GRP_A 0u QTouch Group A.
TOUCH_QT_GRP_B 1u QTouch Group B.
6.3.15.2 Enumerations
This section lists the enumerations used in the QTouch Library.139
6.3.15.2.1 touch_ret_t
Enumeration touch_ret_t
Use Indicates the Touch Library error code.
Values Comment
TOUCH_SUCCESS Successful completion of operation.
TOUCH_ACQ_INCOMPLETE Touch Library is busy with pending previous
Touch measurement.
TOUCH_INVALID_INPUT_PARAM Invalid input parameter.
TOUCH_INVALID_LIB_STATE Operation not allowed in the current Touch
Library state.
TOUCH_INVALID_QM_CONFIG_PARAM Invalid QMatrix config input parameter.
TOUCH_INVALID_AT_CONFIG_PARAM Invalid Autonomous Touch config input
parameter.
TOUCH_INVALID_QT_CONFIG_PARAM Invalid QTouch config input parameter.
TOUCH_INVALID_GENERAL_CONFIG_PARAM Invalid General config input parameter.
TOUCH_INVALID_QM_NUM_X_LINES Mismatch between number of X lines
specified as QM_NUM_X_LINES and
number of X lines enabled in QMatrix pin
configuration touch_qm_pin_t x_lines.
TOUCH_INVALID_QM_NUM_Y_LINES Mismatch between number of Y lines
specified as QM_NUM_Y_LINES and
number of Y lines enabled in QMatrix pin
configuration touch_qm_pin_t y_yk_lines.
TOUCH_INVALID_QM_NUM_SENSORS Number of Sensors specified is greater than
(Number of X Lines * Number of Y Lines).
TOUCH_INVALID_MAXDEV_VALUE Spread spectrum MAXDEV value should not
exceed (2*DIV + 1).
TOUCH_INVALID_RECAL_THRESHOLD Invalid Recalibration threshold input value.
TOUCH_INVALID_CHANNEL_NUM Channel number parameter exceeded total
number of channels configured.
TOUCH_INVALID_SENSOR_TYPE Invalid sensor type. Sensor type can NOT be
SENSOR_TYPE_UNASSIGNED.
TOUCH_INVALID_SENSOR_ID Invalid Sensor number parameter.
TOUCH_INVALID_DMA_PARAM DMA Channel numbers are out of range.
TOUCH_FAILURE_ANALOG_COMP Analog comparator configuration error.
TOUCH_INVALID_RS_NUM Number of Rotor/Sliders set as 0, when trying
to configure a rotor/slider.
6.3.15.2.2 touch_lib_state_t
Enumeration touch_lib_state_t
Use Indicates the current state of the library with respect to a specific acquisition
method
Values Comment
TOUCH_LIB_STATE_NULL Library is not yet initialized for the specific acquisition
method
TOUCH_LIB_STATE_INIT Library is initialized, sensor configuration and calibration is
not yet done.
TOUCH_LIB_STATE_READY Library is ready for a new acquisition in the specific method
TOUCH_LIB_STATE_CALIBRATE Library requires re-calibration before acquisition can be 140 8207L-AT42-05/12
done for the specific acquisition method
TOUCH_LIB_STATE_BUSY Library is busy with acquisition & processing for the specific
acquisition method
6.3.15.2.3 touch_acq_mode_t
Enumeration touch_acq_mode_t
Use Touch library acquisition mode type.
Values Comment
RAW_ACQ_MODE When Raw acquisition mode is used, the measure_complete_callback
function is called immediately once fresh values of Signals are
available. In this mode, the Touch Library does not do any processing
on the Signals. So, the references, Sensor states or Rotor/Slider
position values are not updated in this mode.
NORMAL_ACQ_MODE When Nomal acquisition mode is used, the
measure_complete_callback function is called only after the Touch
Library completes processing of the Signal values obtained. The
References, Sensor states and Rotor/Slider position values are
updated in this mode.
6.3.15.2.4 sensor_type_t
Enumeration sensor_type_t
Use Define the type of the sensor
Values Comment
SENSOR_TYPE_UNASSIGNED Channel is not assigned to any sensor
SENSOR_TYPE_KEY Sensor is a key
SENSOR_TYPE_ROTOR Sensor is a rotor
SENSOR_TYPE_SLIDER Sensor is a slider
6.3.15.2.5 aks_group_t
Enumeration aks_group_t
Use Defines the Adjacent Key Suppression (AKS) groups that each sensor may be
associated with
AKS™ is selectable by the system designer
7 AKS groups are supported by the library
Values Comment
NO_AKS_GROUP No AKS group is selected for the sensor
AKS_GROUP_1 AKS Group number 1
AKS_GROUP_2 AKS Group number 2
AKS_GROUP_3 AKS Group number 3
AKS_GROUP_4 AKS Group number 4
AKS_GROUP_5 AKS Group number 5
AKS_GROUP_6 AKS Group number 6
AKS_GROUP_7 AKS Group number 7
6.3.15.2.6 hysteresis_t
Enumeration Hysteresis_t
Use Defines the sensor detection hysteresis value. This is expressed as a
percentage of the sensor detection threshold.141
This is configurable per sensor.
HYST_x = hysteresis value is x percent of detection threshold value (rounded
down).
Note that a minimum value of 2 is used as a hard limit. Example: if detection
threshold = 20, then:
HYST_50 = 10 (50 percent of 20)
HYST_25 = 5 (25 percent of 20)
HYST_12_5 = 2 (12.5 percent of 20)
HYST_6_25 = 2 (6.25 percent of 20 = 1, but set to the hard limit of 2)
Values Comment
HYST_50 50% Hysteresis
HYST_25 25% Hysteresis
HYST_12_5 12.5% Hysteresis
HYST_6_25 6.25% Hysteresis
6.3.15.2.7 recal_threshold_t
Enumeration recal_threshold_t
Use A sensor recalibration threshold. This is expressed as a percentage of the
sensor detection threshold.
This is for automatic recovery from false conditions, such as a calibration while
sensors were touched, or a significant step change in power supply voltage.
If the false condition persists the library will recalibrate according to the settings
of the recalibration threshold.
This setting is applicable to all the configured sensors.
Usage :
RECAL_x = recalibration threshold is x percent of detection threshold value
(rounded down).
Note: a minimum value of 4 is used.
Example: if detection threshold = 40, then:
RECAL_100 = 40 ( 100 percent of 40)
RECAL_50 = 20 ( 50 percent of 40)
RECAL_25 = 10 ( 25 percent of 40)
RECAL_12_5 = 5 ( 12.5 percent of 40)
RECAL_6_25 = 4 ( 6.25 percent of 40 = 2, but value is limited to 4)
Values Comment
RECAL_100 100% recalibration threshold
RECAL_50 50% recalibration threshold
RECAL_25 25% recalibration threshold
RECAL_12_5 12.5% recalibration threshold
RECAL_6_25 6.25% recalibration threshold
6.3.15.2.8 resolution_t
Enumeration resolution_t
Use For rotors and sliders, the resolution of the reported angle or position.
RES_x_BIT = rotor/slider reports x-bit values.
Example: if slider resolution is RES_7_BIT, then reported positions are in the
range 0..127.142 8207L-AT42-05/12
Values Comment
RES_1_BIT 1 bit resolution : reported positions range 0 – 1
RES_2_BIT 2 bit resolution : reported positions range 0 – 3
RES_3_BIT 3 bit resolution : reported positions range 0 – 7
RES_4_BIT 4 bit resolution : reported positions range 0 – 15
RES_5_BIT 5 bit resolution : reported positions range 0 – 31
RES_6_BIT 6 bit resolution : reported positions range 0 – 63
RES_7_BIT 7 bit resolution : reported positions range 0 – 127
RES_8_BIT 8 bit resolution : reported positions range 0 – 255
6.3.15.2.9 at_status_change_t
Enumeration at_status_change_t
Use Indicates the current status of autonomous QTouch sensor
Values Comment
OUT_OF_TOUCH Currently the autonomous QTouch channel is out of touch
IN_TOUCH Currently the autonomous QTouch channel is in detect
6.3.15.2.10x_pin_options_t
Enumeration x_pin_options_t
Use Options for various pins to be assigned as X lines in QMatrix
Values Comment
Xn Use Pin Xn for QMatrix, n ranges from 0 to 17.
Note: X8 pin must NOT be used as X Line and it is recommended to be used as
ACREFN pin for QMatrix.
6.3.15.2.11y_pin_options_t
Enumeration y_pin_options_t
Use Options for various pins to be assigned as Y lines in QMatrix
Values Comment
Yn_YKn Use Pin Yn & YKn for QMatrix, n ranges from 0 to 7
6.3.15.2.12qt_pin_options_t
Enumeration qt_pin_options_t
Use Options for various pins to be assigned as Sense pair for Autonomous QTouch,
QTouch Group A and QTouch Group B acquisition methods.
Values Comment
SPn Use Sense Pair ‘n’ , n ranges from 0 to 16.
6.3.15.2.13general_pin_options_t
Enumeration general_pin_options_t
Use Options of various pins to be used for SMP, Discharge, SYNC & VDIV.
Values Comment
USE_NO_PIN No Pin is to be assigned for this purpose143
USE_PIN_PA12_AS_SMP Use Pin PA12 as SMP for QMatrix
USE_PIN_PA13_AS_SMP Use Pin PA13 as SMP for QMatrix
USE_PIN_PA14_AS_SMP Use Pin PA14 as SMP for QMatrix
USE_PIN_PA17_AS_SMP Use Pin PA17 as SMP for QMatrix
USE_PIN_PA21_AS_SMP Use Pin PA21 as SMP for QMatrix
USE_PIN_PA22_AS_SMP Use Pin PA22 as SMP for QMatrix
USE_PIN_PA17_AS_DIS Use Pin PA17 as Discharge current control for QMatrix
USE_PIN_PB11_AS_VDIV Use Pin PB11 as Voltage divider enable (VDIVEN) for QMatrix
USE_PIN_PA15_AS_SYNC Use Pin PA15 as external synchronization input signal (SYNC)
USE_PIN_PA18_AS_SYNC Use Pin PA18 as external synchronization input signal (SYNC)
USE_PIN_PA19_AS_SYNC Use Pin PA19 as external synchronization input signal (SYNC)
USE_PIN_PB08_AS_SYNC Use Pin PB08 as external synchronization input signal (SYNC)
USE_PIN_PB12_AS_SYNC Use Pin PB12 as external synchronization input signal (SYNC)
6.3.16 Data structures
This section lists the data structures that hold sensor status, settings, and diagnostics
information.
6.3.16.1 sensor_t
structure sensor_t
Input / Output Output from the library
Use Data structure which holds the sensor state variables used by the library.
Fields Type Comment
state uint8_t internal sensor state
general_counter uint8_t general purpose counter: used for calibration, drifting, etc
ndil_counter uint8_t drift Integration counter
threshold uint8_t sensor detection threshold
type_aks_pos_hyst uint8_t holds information for sensor type, AKS group, positive
recalibration flag, and hysteresis value
Bit fields Use
B1 : B0 Hysteresis
B2 positive recalibration flag
B5:B3 AKS group
B7:B6 sensor type
from_channel uint8_t starting channel number for sensor
to_channel uint8_t ending channel number for sensor
Index uint8_t index for array of rotor/slider values
6.3.16.2 touch_global_param_t
structure touch_global_param_t
Input / Output Input to the Library
Use Holds the sensor acquisition parameters for a specific acquisition method
Fields Type Comment
di uint8_t Sensor detect integration (DI) limit.144 8207L-AT42-05/12
neg_drift_rate uint8_t Sensor negative drift rate in units of 200 ms.
pos_drift_rate uint8_t Sensor positive drift rate in units of 200 ms.
max_on_duration uint8_t Sensor maximum on duration in units of 200ms.
drift_hold_time uint8_t Sensor drift hold time in units of 200 ms.
pos_recal_delay uint8_t Sensor Positive recalibration delay.
recal_threshold recal_threshold_t Sensor recalibration threshold.
Refer Section 5.3 for Overview of Global configuration parameters.
6.3.16.3 touch_filter_data_t
structure touch_filter_data_t
Input / Output Output from the Library
Use Touch Filter Callback data type.
Fields Type Comment
num_channel_signals uint8_t Length of the measured signal values list.
p_channel_signals uint16_t* Pointer to measured signal values for each channel.
6.3.16.4 touch_measure_data_t
structure touch_measure_data_t
Input / Output Output from the Library
Use This structure provides updated measure data values each time the measure
complete callback function is called.
Fields Type Comment
p_acq_status touch_acq_status_t Acquisition status for the specific acquisition
method.
num_channel_signals uint8_t Length of the measured signal values list
p_channel_signals uint16_t* Pointer to the sequential list of measured
signal values of all channels
num_channel_references uint8_t Length of the measured reference values list.
p_channel_references uint16_t* Pointer to the sequential list of reference
values of all channels
num_sensor_states uint8_t Number of sensor state bytes.
p_sensor_states uint8_t* Pointer to the sequential list of touch status of
all sensors
num_rotor_slider_values uint8_t Length of the Rotor and Slider position values list.
p_rotor_slider_values uint8_t* Pointer to the sequential list of position of all
rotors & sliders
num_sensors uint8_t Length of the sensors data list.
p_sensor sensor_t* Pointer to the sequential list of data of all
sensors.
6.3.16.5 touch_qm_param_t
structure touch_qm_param_t
Input / Output Passed as input to touch_qm_sensor_update_config API & got as output from
touch_qm_sensor_get_config API
Use Data structure which holds the configuration parameters for a specific QMatrix
sensor145
Fields Type Comment
aks_group aks_group_t AKS group to which the sensor belong.
detect_threshold threshold_t Detection threshold for the sensor
detect_hysteresis hysteresis_t Detect hysteresis for the sensor.
position_resolution resolution_t Resolution required for the sensor.
position_hysteresis uint8_t Position hysteresis for the sensor
6.3.16.6 touch_at_param_t
structure touch_at_param_t
Input / Output Passed as input to touch_at_sensor_update_config API & got as output from
touch_at_sensor_get_config API
Use Data structure which holds the configuration parameters for the autonomous
QTouch sensor
Structure field Type Corresponds to the device
register
Register Field
filter uint8 t ATCFG2 FILTER
outsens uint8 t ATCFG2 OUTSENS
sense uint8 t ATCFG2 SENSE
pthr uint8 t ATCFG3 PTHR
pdrift uint8 t ATCFG3 PDRIFT
ndrift uint8 t ATCFG3 NDRIFT
Refer Section 5.3 for an overview of FILTER (Detect Integration), PTHR (Positive Recalibration
threshold), PDRIFT (Positive Drift rate) and NDRIFT (Negative Drift rate).
OUTSENS - Autonomous Touch Out-of-Touch Sensitivity.
For the autonomous QTouch sensor, specifies how sensitive the out-of-touch detector should be.
When the sensor is not touched, the Autonomous Touch Current count register is same as the
Autonomous Touch Base count register. When the sensor is touched the Autonomous Touch
Current count register decreases. When using the Autonomous QTouch in proximity mode, the
Autonomous Touch Base count register decreases as we move towards proximity of the sensor.
The OUTSENS value can be arrived at by watching the CAT Autonomous Touch Base Count
Register(at memory location 0xFFFF686Cu) and Autonomous Touch Current Count Register(at
memory location 0xFFFF6870u) during a sensor touch/proximity and not in touch/proximity. A
smaller difference between the Autonomous Touch Base count and Autonomous Touch Current
count register can be chosen as the OUTSENS value. Range: 0u to 255u.
SENSE - Autonomous Touch Sensitivity.
For the autonomous QTouch sensor, specifies how sensitive the touch detector should be.
When the sensor is not touched, the Autonomous Touch Current count register is same as the
Autonomous Touch Base count register. When the sensor is touched the Autonomous Touch
Current count register decreases. When using the Autonomous QTouch in proximity mode, the
Autonomous Touch Base count register decreases as we move towards proximity of the sensor.
The SENSE value can be arrived at by watching the CAT Autonomous Touch Base Count
Register(at memory location 0xFFFF686Cu) and Autonomous Touch Current Count Register(at
memory location 0xFFFF6870u) during a sensor touch/proximity and not in touch/proximity. A
larger difference between the Autonomous Touch Base count and Autonomous Touch Current
count register can be chosen as the SENSE value. Range: 0u to 255u.146 8207L-AT42-05/12
6.3.16.7 touch_qt_param_t
structure touch_qt_param_t
Input / Output Passed as input to touch_qt_sensor_update_config API & got as output from
touch_qt_sensor_get_config API
Use Data structure which holds the status parameters for the QTouch Group A or
Group B sensor.
Fields Type Comment
aks_group aks_group_t AKS group to which the sensor belong.
detect_threshold threshold_t Detection threshold for the sensor
detect_hysteresis hysteresis_t Detect hysteresis for the sensor.
position_resolution resolution_t Resolution required for the sensor.
6.3.16.8 touch_at_status
structure touch_at_status
Input / Output Output structure received as part of the Autonomous QTouch Interrupt callback
function.
Use Data structure which holds the status parameters for the autonomous QTouch
sensor.
Structure
field
Type Comment
status change at status change t Autonomous QTouch Status change.
base_count uint16_t The base count currently stored by the autonomous touch
sensor. This is useful for autonomous touch debugging
purposes.
current_count uint16_t The current count acquired by the autonomous touch
sensor. This is useful for autonomous touch debugging
purposes.
6.3.16.9 touch_qm_dma_t
structure touch_qm_dma_t
Input / Output Input to the touch_qm_sensors_start_acquisition() API.
Use Data structure which holds the DMA channel information for touch acquisition
data transfer
Fields Type Comment
dma_ch1 uint8_t Indicates the DMA channel 1. Can take values from 0 – 11, but should not
be same as dma_ch2
dma_ch2 uint8_t Indicates the DMA channel 2. Can take values from 0 – 11, but should not
be same as dma_ch1
6.3.16.10 touch_qm_pin_t
structure touch_qm_pin_t
Input / Output Input to the library
Use Data structure which holds the Pin configuration information for QMatrix147
Fields Type Comment
x_lines uint32_t Bitmask that indicates the selected X pins for QMatrix. If bit n is set, Xn is
enabled for QMatrix; n can be 0 to 17. Any other bits set are ignored. Note:
For QMatrix operation, X8 is not available as it must be used for ACREFN
function.
Bit 18
-
31
17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2
X
Line
- X
17
X
16
X
15
X
14
X
13
X
12
X
11
X
10
X
9
X
8
X
7
X
6
X
5
X
4
X
3
X
2
y_yk_lin
es
uint8_t Bitmask that indicates the selected Y pins for QMatrix. If bit n is set, Yn &
Ykn is enabled for QMatrix; n can be 0 to 7.
Bit 7 6 5 4 3 2 1 0
Y
Line
Y7 &
YK7
Y6 &
YK6
Y5 &
YK5
Y4 &
YK4
Y3 &
YK3
Y2 &
YK2
Y1 &
YK1
Y0 &
YK0
smp_di
s_pin
general
_pin_op
tions_t
Specify one of the following
USE_NO_PIN
USE_PIN_PA12_AS_SMP
USE_PIN_PA13_AS_SMP
USE_PIN_PA14_AS_SMP
USE_PIN_PA17_AS_SMP
USE_PIN_PA21_AS_SMP
USE_PIN_PA22_AS_SMP
USE_PIN_PA17_AS_DIS
vdiv_pi
n
general
_pin_op
tions_t
Specify either USE_NO_PIN or USE_PIN_PB11_AS_VDIV
6.3.16.11 touch_at_pin_t
structure touch_at_pin_t
Input / Output Input to the library
Use Data structure which holds the Pin configuration for Autonomous QTouch
sensor
Fields Type Comment
atsp uint8_t Sense pair to be used for autonomous QTouch detection. Choose any one
sense pair from SP0 to SP16 using the qt_pin_options_t enum.
For example, if atsp is set as SP7, Sense pair 7 (CSA7, CSB7) will be assigned
for autonomous QTouch detection
6.3.16.12 touch_qt_pin_t
structure touch_at_pin_t
Input / Output Input to the library
Use Data structure which holds the Pin configuration for QTouch sensor.
Fiel
ds
Type Comment148 8207L-AT42-05/12
sp uint3
2_t
Bit n indicates Sense Pair SP[n] is selected. Choose sense pairs from SP0 to
SP16.
Bit 1
7-
3
1
16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
SP
n
- X1
6
X1
5
X1
4
X1
3
X1
2
X1
1
X1
0
X
9
X
8
X
7
X
6
X
5
X
4
X
3
X
2
X
1
X
0
6.3.16.13 touch_qm_reg_t
structure touch_qm_reg_t
Input / Output Input to the library
Use Data structure which holds the Register configuration information for QMatrix
This structure contains the data fields that correspond to specific fields in different registers. For a
more detailed explanation of the register fields, refer to the device datasheet.
For example, CHLEN field of MCCFG0 is 8 bits wide (bit 8-15 of MGCFG0 register). The user
needs to set values from 0 to 255 (0xFF) in the chlen field of this structure. The library will take
care of writing this to the appropriate bit position of MCCFG0 register.
Fields Type Corresponds to Register Register Field
div uint16 t MGCFG0 DIV
chlen uint8 t MGCFG0 CHLEN
selen uint8 t MGCFG0 SELEN
dishift uint8 t MGCFG1 DISHIFT
sync uint8 t MGCFG1 SYNC
spread uint8 t MGCFG1 SPREAD
dilen uint8 t MGCFG1 DILEN
max uint16 t MGCFG1 MAX
acctrl uint8 t MGCFG2 ACCTRL
consen uint8 t MGCFG2 CONSEN
cxdilen uint8 t MGCFG2 CXDILEN
synctim uint16 t MGCFG2 SYNCTIM
fsources uint8 t DICS FSOURCES
glen uint8 t DICS GLEN
intvrefsel uint8 t DICS INTVREFSEL
Intrefsel uint8 t DICS INTREFSEL
trim uint8 t DICS TRIM
sources uint8 t DICS SOURCES
shival0 uint16 t ACSHI0 SHIVAL
shival1 uint16 t ACSHI1 SHIVAL
shival2 uint16 t ACSHI2 SHIVAL
shival3 uint16 t ACSHI3 SHIVAL
shival4 uint16 t ACSHI4 SHIVAL
shival5 uint16 t ACSHI5 SHIVAL
shival6 uint16 t ACSHI6 SHIVAL
shival7 uint16 t ACSHI7 SHIVAL149
6.3.16.14 touch_at_reg_t
structure touch_at_reg_t
Input / Output Input to the library
Use Data structure which holds the Register configuration information for
Autonomous QTouch
This structure contains the data fields that correspond to specific fields in different registers. For a
more detailed explanation of the register fields, refer to the device datasheet.
For example, DISHIFT field of ATCFG1 is 2 bits wide (bit 28-29 of ATCFG1 register). The user
needs to set values from 0 to 3 in the dishift field of this structure. The library will take care of
writing this to the appropriate bit position of ATCFG1 register.
Fields Type Corresponds to Register Register Field
div uint16 t ATCFG0 DIV
chlen uint8 t ATCFG0 CHLEN
selen uint8 t ATCFG0 SELEN
dishift uint8 t ATCFG1 DISHIFT
sync uint8 t ATCFG1 SYNC
spread uint8 t ATCFG1 SPREAD
dilen uint8 t ATCFG1 DILEN
max uint16 t ATCFG1 MAX
at_param touch_at_param_t Autonomous Touch Sensor
parameters corresponding to
ATCFG2 and ATCFG3.
FILTER, OUTSENS,
SENSE, PTHR,
PDRIFT, NDRIFT
6.3.16.15 touch_qt_reg_t
structure touch_qt_reg_t
Input / Output Input to the library
Use Data structure which holds the Register configuration information for QTouch
Group A/B.
Fields Type Corresponds to Register Register Field
div uint16 t TGxCFG0 DIV
chlen uint8 t TGxCFG0 CHLEN
selen uint8 t TGxCFG0 SELEN
dishift uint8 t TGxCFG1 DISHIFT
sync uint8 t TGxCFG1 SYNC
spread uint8 t TGxCFG1 SPREAD
dilen uint8 t TGxCFG1 DILEN
max uint16 t TGxCFG1 MAX
6.3.16.16 touch_qm_config_t
structure touch_qm_config_t
Input / Output Input to the library
Use Data structure which holds all configuration information pertaining to QMatrix
Fields Type Comment
num_channels uint8_t Indicates the number of QMatrix channels
required by the user150 8207L-AT42-05/12
num_sensors uint8_t Indicates the number of QMatrix sensors
required by the user.
num_rotors_and_slider
s
uint8_t Indicates the number of QMatrix rotors /
sliders required by the user.
num_x_lines uint8_t Number of QMatrix X lines required by the
user.
num_y_lines uint8_t Number of QMatrix Y lines required by the
user.
num_x_sp uint8_t Number of X sense pairs used. This is a
private variable to the Touch library. The user
must provide
PRIV_QM_NUM_X_SENSE_PAIRS for this
input field.
bl_write_count uint8_t Burst length write count. This is a private
variable to the Touch library. The user must
provide the
PRIV_QM_BURST_LENGTH_WRITE_COUN
T macro for this input field.
pin touch_qm_pin_t Holds the QMatrix Pin configuration
information as filled by the user.
reg touch_qm_reg_t Holds the QMatrix register configuration
information as filled by the user.
global_param touch_global_param_
t
Holds the global parameters for QMatrix as
filled by the user.
p_data_blk uint8_t* Pointer to the data block allocated by the user
buffer_size uint16_t Size of the data block pointed to by
p_data_blk. The user must provide the
PRIV_QM_DATA_BLK_SIZE macro for this
input field.
p_burst_length uint8_t* Pointer to an array of 8-bit Burst lengths,
where each 8-bit value correspond to the burst
length of each channel starting from channel 0
to number of channels.
filter_callback Pointer to a function Pointer to callback function that will be called
before processing the signals
6.3.16.17 touch_at_config_t
structure touch_at_config_t
Input / Output Input to the library
Use Data structure which holds the configuration parameters & register values for
autonomous QTouch acquisition
Fields Type Comment
pin touch_at_pin_t Holds the autonomous QTouch
configuration information as filled by the
user.
reg touch_at_reg_t Holds the autonomous QTouch register
configuration information as filled by the
user.
touch_at_status_change_callback Pointer to a
function
Pointer to callback function that will be
called by the library whenever there is a
touch status change in the autonomous
QTouch sensor151
6.3.16.18 touch_qt_config_t
structure touch_qm_config_t
Input / Output Input to the library
Use Data structure which holds all configuration information pertaining to QMatrix
Fields Type Comment
num_channels uint8_t Indicates the number of QTouch Group A/B
channels required by the user
num_sensors uint8_t Indicates the number of QTouch Group A/B
sensors required by the user.
num_rotors_and_sliders uint8_t Indicates the number of QTouch Group A/B
rotors / sliders required by the user.
pin touch_qt_pin_t Holds the QTouch Group A/B Pin
configuration information as filled by the user.
reg touch_qt_reg_t Holds the QTouch Group A/B register
configuration information as filled by the user.
global_param touch_global_param_t Holds the global parameters for QTouch
Group A/B as filled by the user.
p_data_blk uint8_t* Pointer to the data block allocated by the user
buffer_size uint16_t Size of the data block pointed to by
p_data_blk. The user must provide the
PRIV_QTA_DATA_BLK_SIZE or
PRIV_QTB_DATA_BLK_SIZE macro for this
input field.
filter_callback Pointer to a function Pointer to callback function that will be called
before processing the signals
6.3.16.19 touch_general_config_t
structure touch_general_config_t
Input / Output Input to the library
Use Data structure which holds the configuration parameters & register values
common to all acquisition methods.
Fields Type Comment
sync_pin general_pin_options_t Specify one of the following values indicating the pin to be
assigned as SYNC pin. Refer to the device datasheet for
more details.
USE_NO_PIN
USE_PIN_PA15_AS_SYNC
USE_PIN_PA18_AS_SYNC
USE_PIN_PA19_AS_SYNC
USE_PIN_PB08_AS_SYNC
USE_PIN_PB12_AS_SYNC
maxdev uint8_t Corresponds to MAXDEV field of SSCFG register that
indicates the maximum deviation when spread spectrum is
enabled.
Ensure that maxdev is always less than or equal to (2*div +
1).
div represents div field in touch_qm_reg_t & touch_at_reg_t
structures.152 8207L-AT42-05/12
csares uint32_t Corresponds to RES field of CSARES register.
csbres uint32_t Corresponds to RES field of CSBRES register.
6.3.16.20 touch_config_t
structure touch_config_t
Input / Output Input to the library
Use Pointer to this structure is passed as input to touch_qm_sensors_init &
touch_at_sensor_init APIs
Fields Type Comment
p_qm_config touch_qm_config_t* Pointer to the QMatrix configuration structure.
p_at_config touch_at_config_t* Pointer to the autonomous QTouch configuration
structure.
p_qta_config touch_qt_config_t* Pointer to the QTouch Group A configuration
structure.
p_qtb_config touch_qt_config_t* Pointer to the QTouch Group B configuration
structure.
p_general_config touch_general_config_t* Pointer to the general configuration structure.
6.3.16.21 touch_info_t
structure touch_info_t
Input / Output Output from the library
Use Pointer to this structure is passed as input to touch_qm_get_libinfo &
touch_at_get_libinfo APIs
Fields Type Comment
num_channels_in_use uint8_t Number of channels in use
num_sensors_in_use uint8_t Number of sensors in use
num_rotors_sliders_in_use uint8_t Number of rotor/sliders in use
max_channels_per_rotor_slider uint8_t Maximum number of channels per rotor/slider
allowed by the library
hw_version uint32_t CAT module hardware revision as per VERSION
register in CAT module.
fw_version uint16_t QTouch Library version with MSB indicating the
major version & LSB indicating the minor version.
6.3.17 Public Functions of QTouch Library for UC3L
This section lists the public functions available in the QTouch™ libraries for AT32UC3L devices.
6.3.17.1 QMatrix API
This section lists the functions that are specific to QMatrix method of acquisition.
6.3.17.1.1 touch_qm_sensors_init
touch_ret_t touch_qm_sensors_init (touch_config_t *p_touch_config)
Arguments Type Comment
p_touch_config touch_config_t* Pointer to Touch Library input configuration structure. The
touch_qm_config_t and touch_general_config_t members of
the Structure should be non-NULL.153
• This API initializes the Touch library for QMatrix method acquisition. This API has to be
called before calling any other QMatrix API.
• Based on the input parameters, the CAT module is initialized with QMatrix method Pin
and Register configuration.
• The Analog comparators necessary for QMatrix operation are initialized by this API.
• Both p_qm_config & p_general_config members of the input configuration structure must
point to valid configuration data.
• The General configuration data provided by the p_general_config pointer is common to
both QMatrix, QTouch Group A, QTouch Group B and Autonomous Touch sensors.
6.3.17.1.2 touch_qm_sensor_config
touch_ret_t touch_qm_sensor_config(
sensor_type_t sensor_type,
channel_t from_channel,
channel_t to_channel,
aks_group_t aks_group,
threshold_t detect_threshold,
hysteresis_t detect_hysteresis,
resolution_t position_resolution,
uint8_t position_hysteresis,
sensor_id_t *p_sensor_id)
Arguments Type Comment
sensor_type sensor_type_t Specifies sensor type – SENSOR_TYPE_KEY or
SENSOR_TYPE_ROTOR or
SENSOR_TYPE_SLIDER.
The SENSOR_TYPE_UNASSIGNED enum is not a valid
input to this API.
from_channel channel_t Start channel of the Sensor (rotor, slider or key).
to_channel channel_t End channel of the Sensor (rotor, slider or key). For a key,
the start and end channels must be the same.
aks_group aks_group_t AKS group of this sensor.
detect_threshold threshold_t Touch Detect threshold level for Sensor.
detect_hysteresis hysteresis_t Value for detection hysteresis.
position_resolution resolution_t Position resolution when configuring rotor / slider
position_hysteresis uint8_t Position hysteresis when configuring rotor / slider
p_sensor_id sensor_id_t* The Sensor ID is updated by the Touch Library upon
successful sensor configuration. The Sensor ID starts with
0.
• This API configures a single QMatrix Key, Rotor or Slider.
• The user must provide all the sensor specific settings as input to this API.
• Rotor / Slider sensor will occupy contiguous channels from from_channel to to_channel.154 8207L-AT42-05/12
• For QMatrix acquisition method, 3 to 8 Touch channels per rotor / slider are supported.
Keys are always formed using 1 Touch channel.
6.3.17.1.3 touch_qm_sensor_update_config
touch_ret_t touch_qm_sensor_update_config(
sensor_id_t sensor_id,
touch_qm_param_t *p_touch_sensor_param)
Arguments Type Comment
sensor_id sensor_id_t Sensor ID for which the configuration
needs to be updated.
p_touch_sensor_param touch_qm_param_t* Pointer to the user sensor configuration
structure.
• This API updates the configuration of a QMatrix sensor with values different from the
ones initialized by the touch_qm_sensor_config API. If the sensor was not configured
already, the API will return error.
• The user must populate the structure pointed by p_touch_sensor_param with required
settings before calling this API.
6.3.17.1.4 touch_qm_sensor_get_config
touch_ret_t touch_qm_sensor_get_config(
sensor_id_t sensor_id,
touch_qm_param_t *p_touch_sensor_param)
Arguments Type Comment
sensor_id sensor_id_t Sensor ID for which the configuration
needs to be updated.
p_touch_sensor_param touch_sensor_param_t* Pointer to the user sensor configuration
structure.
• This API copies the current configuration of a QMatrix sensor into the user configuration
structure.
6.3.17.1.5 touch_qm_channel_udpate_burstlen
touch_ret_t touch_qm_channel_udpate _burstlen(
channel_t channel,
touch_bl_t qm_burst_length)
Arguments Type Comment
channel uint8_t Channel number for which the burst length is to be set.
qm_burst_length touch_bl_t QMatrix burst length. The burst length value can be 1 to
255. A value of 1 can be used to disable bursting on
a given channel.
• This API updates the burst length of the specified QMatrix channel
• This API can also be used to disable Touch measurement on a Sensor. 155
• In order to disable a Sensor, the burst length value of all the channels corresponding to
the Sensor must be set to 1. A Sensor can then be re-enabled by setting the appropriate
burst length for all channels using this API.
Note: When disabling a sensor care must be taken such that all channels of the Sensor
are set to 1. If any of the channels are missed out, it will result in undesired behavior of
the Sensor. Similarly when re-enabling a Sensor, if one or more channels are left
disabled with a burst length value of 1, it will result in undesired behavior of the Sensor.
• The touch_qm_sensors_calibrate API needs to be called whenever burst length is
updated for one or more channels before starting a new Touch measurement using the
touch_qm_sensors_start_acquisition API.
6.3.17.1.6 touch_qm_update_global_param
touch_ret_t touch_qm_update_global_param( touch_global_param_t *p_global_param )
Arguments Type Comment
p_global_param touch_global_param_t Pointer to user global parameters structure for
QMatrix.
• This API can be used to update the QMatrix global parameters, with values different from
the ones initialized using touch_qm_sensors_init API.
6.3.17.1.7 touch_qm_get_global_param
touch_ret_t touch_qm_get_global_param( touch_global_param_t *p_global_param )
Arguments Type Comment
p_global_param touch_global_param_t Pointer to user global parameters structure for
QMatrix.
• This API can be called to retrieve the QMatrix global parameters.
6.3.17.1.8 touch_qm_sensors_calibrate
touch_ret_t touch_qm_sensors_calibrate( void )
Arguments Type Comment
Void -
• This API can be used to calibrate all configured Sensors.
• Calibration of all Sensors must be performed when –
o All the Sensors have been configured using touch_sensor_config API after
initialization of the Touch Library.
o A sensor or a group of Sensors have been disabled or re-enabled. 156 8207L-AT42-05/12
6.3.17.1.9 touch_qm_sensors_start_acquisition
touch_ret_t touch_qm_sensors_start_acquisition(
touch_time_t current_time_ms,
touch_qm_dma_t *p_touch_dma,
touch_acq_mode_t qm_acq_mode,
void (*measure_complete_callback)( touch_measure_data_t *p_measure_data ))
Arguments Type Comment
current_time_ms touch_time_t Current time in ms
p_touch_dma touch_qm_dma_t* DMA channels to be
used for transfer to burst
length & acquisition
count
qm_acq_mode touch_acq_mode_t Specify whether Normal
acquisition mode or
Raw acquisition mode
should be done.
void
(*measure_complete_callback)(
void )
void
(*measure_complete_callback)(
touch_measure_data_t
*p_measure_data)
QMatrix Measure
complete callback
function pointer
• This API initiates a capacitive measurement on all enabled QMatrix sensors.
• When normal acquisition mode is used, once the Touch measurement is completed on all
the QMatrix sensors, before processing the raw acquisition data (channel_signals), a
filter_callback function is optionally called by the Touch Library.
• Once the filter_callback is completed, the signal values will be processed by the Touch
Library. The measure_complete_callback function is then called with touch data
(channel_signals, channel_references, sensor_states, sensors structure) as well as the
Touch Status (sensor_states) and Rotor/Slider position (rotor_slider_values).
• The touch_event_dispatcher API needs to be called as frequently as possible for the
Touch Library to process the raw acquisition data.
• When raw data acquisition mode is used, once the raw acquisition data is available from
the CAT module for all the sensors, the measure_complete_callback function is
immediately called with acquisition data (channel_signals). The channel_references,
sensor_states and rotor_slider_values data are not updated by the Touch Library in this
mode.
• This API will return error if a Touch measurement is already in progress.
• Two peripheral DMA channels must be provided using p_touch_dma for QMatrix
operation.
6.3.17.1.10 touch_qm_get_libinfo
touch_ret_t touch_qm_get_libinfo( touch_info_t *p_touch_info)
Arguments Type Comment
p_
touch_info
touch_info_t* User passes the memory address at which the library information
is to be stored by the library.157
• The touch_info_t structure is filled by the library with information like number of QMatrix
channels, number of QMatrix sensors, number of QMatrix rotors/slider, CAT hardware
version, and library version.
• The QMatrix number of channels, sensors and rotors/slider indicate the total number of
channels, sensors and rotor/slider in use irrespective of Touch measured being disabled
or enabled. (Disabling and Re-enabling of a Sensor using the
touch_qm_sensor_upate_burstlen API does not alter these values).
6.3.17.1.11touch_qm_sensor_get_delta
touch_ret_t touch_qm_sensor_get_delta(
sensor_id_t sensor_id,
touch_delta_t *p_delta)
Arguments Type Comment
sensor_id sensor_id_t Sensor ID for which the delta needs to be retrieved.
p_delta touch_delta_t* Pointer to Delta variable, that will be update by the Touch Library
• This API retrieves the delta information associated with a specific QMatrix sensor. Delta
is the difference between the current signal value and reference value.
• The user must provide the sensor ID whose delta is sought along with a valid pointer to a
Delta variable.
• The API updates the delta variable associated with the requested sensor.
6.3.17.2 QTouch Group A and QTouch Group B API
This section lists the functions that are specific to QTouch Group A/B method of acquisition.
6.3.17.2.1 touch_qt_sensors_init
touch_ret_t touch_qt_sensors_init (touch_qt_grp_t touch_qt_grp,
touch_config_t *p_touch_config)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A
Sensors or Group B Sensors.
p_touch_config touch_config_t* Pointer to Touch Library input configuration structure. The
p_qta_config/p_qtb_config (based on whether Group A is
used or Group B is used) and p_general_config members of
the Structure should be non-NULL.
• This API initializes the Touch library for QTouch Group A or QTouch Group B method
acquisition. This API has to be called before calling any other QTouch API.
• Based on the input parameters, the CAT module is initialized with QTouch method Pin
and Register configuration.
• The p_qta_config/p_qta_config (based on whether Group A is used or Group B is used)
and p_general_config members of the input configuration structure must point to valid
configuration data.158 8207L-AT42-05/12
• The General configuration data provided by the p_general_config pointer is common to
both QMatrix, QTouch Group A, QTouch Group B and Autonomous Touch sensors.
6.3.17.2.2 touch_qt_sensor_config
touch_ret_t touch_qt_sensor_config(touch_qt_grp_t touch_qt_grp,
sensor_type_t sensor_type,
channel_t from_channel,
channel_t to_channel,
aks_group_t aks_group,
threshold_t detect_threshold,
hysteresis_t detect_hysteresis,
resolution_t position_resolution
sensor_id_t *p_sensor_id)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A
Sensors or Group B Sensors.
sensor_type sensor_type_t Specifies sensor type – SENSOR_TYPE_KEY or
SENSOR_TYPE_ROTOR or
SENSOR_TYPE_SLIDER.
The SENSOR_TYPE_UNASSIGNED enum is not a valid
input to this API.
from_channel channel_t Start channel of the Sensor (rotor, slider or key).
to_channel channel_t End channel of the Sensor (rotor, slider or key). For a
key, the start and end channels must be the same.
aks_group aks_group_t AKS group of this sensor.
detect_threshold threshold_t Touch Detect threshold level for Sensor.
detect_hysteresis hysteresis_t Value for detection hysteresis.
position_resolution resolution_t Position resolution when configuring rotor / slider
p_sensor_id sensor_id_t* The Sensor ID is updated by the Touch Library upon
successful sensor configuration. The Sensor ID starts with
0.
• This API configures a single QTouch Key, Rotor or Slider.
• The user must provide all the sensor specific settings as input to this API.
• Rotor / Slider sensor will occupy contiguous channels from from_channel to to_channel.
• For QTouch acquisition method, 3 Touch channels per rotor / slider are supported. Keys
are always formed using 1 Touch channel.
6.3.17.2.3 touch_qt_sensor_update_config
touch_ret_t touch_qt_sensor_update_config(touch_qt_grp_t touch_qt_grp,
sensor_id_t sensor_id,
touch_qt_param_t *p_touch_sensor_param)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be
performed on Group A Sensors or
Group B Sensors.159
sensor_id sensor_id_t Sensor ID for which the configuration
needs to be updated.
p_touch_sensor_param touch_qt_param_t * Pointer to the user sensor configuration
structure.
• This API updates the configuration of a QTouch sensor with values different from the
ones initialized by the touch_qt_sensor_config API. If the sensor was not configured
already, the API will return error.
• The user must populate the structure pointed by p_touch_sensor_param with required
settings before calling this API.
6.3.17.2.4 touch_qt_sensor_get_config
touch_ret_t touch_qt_sensor_get_config(touch_qt_grp_t touch_qt_grp,
sensor_id_t sensor_id,
touch_qt_param_t *p_touch_sensor_param)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be
performed on Group A Sensors or
Group B Sensors.
sensor_id sensor_id_t Sensor ID for which the configuration
needs to be updated.
p_touch_sensor_param touch_qt_param_t* Pointer to the user sensor configuration
structure.
• This API copies the current configuration of a QTouch sensor into the user configuration
structure.
6.3.17.2.5 touch_qt_update_global_param
touch_ret_t touch_qt_update_global_param(touch_qt_grp_t touch_qt_grp,
touch_global_param_t *p_global_param )
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A
Sensors or Group B Sensors.
p_global_param touch_global_param_t Pointer to user global parameters structure for
QTouch Group A/B.
• This API can be used to update the QTouch A or QTouch B global parameters, with
values different from the ones initialized using touch_qt_sensors_init API.
6.3.17.2.6 touch_qt_get_global_param
touch_ret_t touch_qt_get_global_param(touch_qt_grp_t touch_qt_grp,
touch_global_param_t *p_global_param )
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A
Sensors or Group B Sensors.160 8207L-AT42-05/12
p_global_param touch_global_param_t Pointer to user global parameters structure for
QTouch Group A/B.
• This API can be called to retrieve the QTouch Group A or Group B global parameters.
6.3.17.2.7 touch_qt_sensors_calibrate
touch_ret_t touch_qt_sensors_calibrate(touch_qt_grp_t touch_qt_grp )
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be
performed on Group A Sensors or
Group B Sensors.
• This API can be used to calibrate all configured Sensors.
• Calibration of all Sensors must be performed when –
o All the Sensors have been configured using touch_sensor_config API after
initialization of the Touch Library.
o A sensor or a group of Sensors have been disabled or re-enabled.
6.3.17.2.8 touch_qt_sensors_start_acquisition
touch_ret_t touch_qt_sensors_start_acquisition(touch_qt_grp_t touch_qt_grp,
touch_time_t current_time_ms,
touch_qt_dma_t *p_touch_dma,
touch_acq_mode_t qt_acq_mode,
void (*measure_complete_callback)( touch_measure_data_t *p_measure_data ))
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation
is to be performed on
Group A Sensors or
Group B Sensors.
current_time_ms touch_time_t Current time in ms
p_touch_dma touch_qt_dma_t* DMA channels to be
used for transfer to burst
length & acquisition
count
qt_acq_mode touch_acq_mode_t Specify whether Normal
acquisition mode or
Raw acquisition mode
should be done.
void
(*measure_complete_callback)(
void )
void
(*measure_complete_callback)(
touch_measure_data_t
*p_measure_data)
QTouch Group A or
Group B Measure
complete callback
function pointer
• This API initiates a capacitive measurement on all enabled QTouch Group A or Group B
sensors depending on the touch_qt_grp specified.161
• When normal acquisition mode is used, once the Touch measurement is completed on all
the QTouch sensors, before processing the raw acquisition data (channel_signals), a
filter_callback function is optionally called by the Touch Library.
• Once the filter_callback is completed, the signal values will be processed by the Touch
Library. The measure_complete_callback function is then called with touch data
(channel_signals, channel_references, sensor_states, sensors structure) as well as the
Touch Status (sensor_states) and Rotor/Slider position (rotor_slider_values).
• The touch_event_dispatcher API needs to be called as frequently as possible for the
Touch Library to process the raw acquisition data.
• When raw data acquisition mode is used, once the raw acquisition data is available from
the CAT module for all the sensors, the measure_complete_callback function is
immediately called with acquisition data (channel_signals). The channel_references,
sensor_states and rotor_slider_values data are not updated by the Touch Library in this
mode.
• This API will return error if a Touch measurement is already in progress.
• One peripheral DMA channels must be provided using p_touch_dma for QTouch
operation.
6.3.17.2.9 touch_qt _sensor_ disable
touch_ret_t touch_qt_ sensor_disable(touch_qt_grp_t touch_qt_grp,
sensor_id_t sensor_id)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A Sensors
or Group B Sensors.
sensor_id sensor_id_t Sensor ID of the Sensor to be disabled.
• This API can be used to disable Touch measurement on a QTouch Sensor.
• The touch_qt_sensors_calibrate API needs to be called whenever one or more Sensors
are disabled before starting a new Touch measurement using the
touch_qt_sensors_start_acquisition API.
• Note: Care must be taken such that a valid Sensor ID corresponding to a QTouch Group
A sensor or QTouch Group B Sensor is provided.
6.3.17.2.10 touch_qt _sensor_ reenable
touch_ret_t touch_qt _sensor_reenable(touch_qt_grp_t touch_qt_grp,
sensor_id_t sensor_id)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A Sensors
or Group B Sensors.
sensor_id sensor_id_t Sensor ID of the Sensor to be disabled.
• This API can be used to reenable a disabled QTouch Sensor. 162 8207L-AT42-05/12
• The touch_qt_sensors_calibrate API needs to be called whenever one or more Sensors
are reenabled before starting a new Touch measurement using the
touch_qt_sensors_start_acquisition API.
• Note: Care must be taken such that a valid Sensor ID corresponding to a QTouch Group
A sensor or QTouch Group B Sensor is provided.
6.3.17.2.11 touch_qt_get_libinfo
touch_ret_t touch_qt_get_libinfo(touch_qt_grp_t touch_qt_grp,
touch_info_t *p_touch_info)
Arguments Type Comment
touch_qt_grp touch_qt_grp_t Specify if the operation is to be performed on Group A Sensors
or Group B Sensors.
p_
touch_info
touch_info_t* User passes the memory address at which the library
information is to be stored by the library.
• The touch_info_t structure is filled by the library with the Group specific (based on
touch_qt_grp input) information like number of QTouch channels, number of QTouch
sensors, number of QTouch rotors/slider, CAT hardware version, and library version.
• The QTouch number of channels, sensors and rotors/slider indicate the total number of
channels, sensors and rotor/slider in use irrespective of Touch measured being disabled
or enabled. (Disabling and Re-enabling of a Sensor using the touch_qt_sensor_disable
and touch_qt_sensor_reenable API does not alter these values).
6.3.17.2.12touch_qt_sensor_get_delta
touch_ret_t touch_qt_sensor_get_delta(touch_qt_grp_t touch_qt_grp,
sensor_id_t sensor_id,
touch_delta_t *p_delta)
Arguments Type Comment
sensor_id sensor_id_t Sensor ID for which the delta needs to be retrieved.
p_delta touch_delta_t* Pointer to Delta variable, that will be update by the Touch Library
• This API retrieves the delta information associated with a specific QTouch sensor. Delta
is the difference between the current signal value and reference value.
• The user must provide the sensor ID whose delta is sought along with a valid pointer to a
Delta variable.
• The API updates the delta variable associated with the requested sensor.
6.3.18 Autonomous touch API
This section lists the functions that are specific to Autonomous QTouch sensor.
6.3.18.1.1 touch_at_sensor_init
touch_ret_t touch_at_sensor_init( touch_config_t *p_touch_config )163
Arguments Type Comment
p_touch_config touch_config_t* Pointer to Touch Library input configuration structure. The
p_at_config and p_general_config members of the input
configuration structure must be non-NULL.
• This API initializes the touch library Autonomous touch sensor. This API has to be called
before calling any other Autonomous touch API function.
• Based on the input parameters, the CAT module is initialized with Autonomous Sensor
Pin and Register configuration.
• The General configuration data provided by the p_general_config pointer is common to
both QMatrix, QTouch Group A, QTouch Group B and Autonomous Touch sensors.
6.3.18.1.2 touch_at_sensor_enable
touch_ret_t touch_at_sensor_enable( void)
Arguments Type Comment
void
(*touch_at_status_change_interrupt_
callback) (touch_at_status
*p_at_status)
void
(*touch_at_status_change_interrupt
_callback) (touch_at_status
*p_at_status)
Autonomous
QTouch Callback
function.
• This API enables the autonomous touch sensor and initiates continuous Touch
measurement on the Autonomous QTouch sensor.
• When there is a change in the autonomous QTouch sensor status, the callback function
as specified in touch_at_status_change_interrupt_callback will be called. The callback
function lets the user know whether the autonomous QTouch sensor is currently in touch
or out of touch.
Note that this callback function will be called from an interrupt service routine. Hence it is
recommended to have as minimal code as possible in the callback function.
• This API should be called only after touch_at_sensor_init API is called.
6.3.18.1.3 touch_at_sensor_disable
touch_ret_t touch_at_sensor_disable( void)
Arguments Type Comment
void -
• This API disables the Touch measurement on the Autonomous QTouch sensor. The
status change callback function is not called when the Sensor is disabled.
6.3.18.1.4 touch_at_sensor_update_config
touch_ret_t touch_at_sensor_update_config( touch_at_param_t *p_at_param )
Arguments Type Comment164 8207L-AT42-05/12
p_at_param touch_at_param_t* Pointer to autonomous QTouch sensor configuration
structure.
• This API updates the configuration of autonomous QTouch sensor with a setting that is
different from the one configured by calling touch_at_sensor_init API.
• The user must populate the structure pointed by p_at_param with required settings
before calling this API.
6.3.18.1.5 touch_at_sensor_get_config
touch_ret_t touch_at_sensor_get_config( touch_at_param_t *p_at_param )
Arguments Type Comment
p_at_param touch_at_param_t* Pointer to autonomous QTouch sensor configuration
structure.
• This API retrieves the current configuration of the autonomous QTouch sensor.
6.3.18.1.6 touch_at_get_libinfo
touch_ret_t touch_at_get_libinfo( touch_info_t *p_touch_info)
Arguments Type Comment
p_touch_info touch_info_t* User passes the memory address at which the library information
is to be updated.
• The touch_info_t structure is filled by the library with information on the number of
autonomous QTouch channels (Fixed value of 1), number of autonomous QTouch
sensors (Fixed value of 1), number of autonomous QTouch rotors/slider (Fixed value of
0), CAT hardware version and library version.
6.3.18.2 Common API
This section lists the functions that are common to QMatrix, QTouch Group A/B and Autonomous
QTouch acquisition methods.
6.3.18.2.1 touch_event_dispatcher
void touch_event_dispatcher ( void )
Arguments Type Comment
Void -
• This API needs to be called by the user application to allow the library to process the raw
acquisition data from the sensors.
• Once touch_qm_sensors_start_acquisition is called, touch_event_dispatcher API needs
to be called as frequently as possible by the Host application.
• The signals_callback and measure_complete_callback functions are called from the
touch_event_dispatcher API context.
6.3.18.2.2 touch_deinit
void touch_deinit (void)165
Arguments Type Comment
void -
• This API can be used to de-initalize the Touch Library and disable the CAT module.
• Calling this API de-initializes the Touch Library for Sensors corresponding to all methods
of acquisition (QMatrix, QTouch Group A, QTouch Group B and Autonomous QTouch).
6.3.19 Integrating QTouch libraries for AT32UC3L in your application
This section illustrates the key steps required in integrating the QTouch™ library in your
application.
a. For your design, you would need the following information to select the correct library
variant
• Device to be used for the design – Current library supports AT32UC3L064,
AT32UC3L032, AT32UC3L016 device variants.
• Compiler platform you intend to use to integrate the libraries.
b. Copy the library variant that was selected in step one to your project’s working directory
or update your project to point to the library selected.
c. Include touch_api_at32uc3l.h & touch_config_at32uc3l.h header files of the QTouch™
library in your application. The header files can be found in the library installation folder.
d. Initialize/create and use the Touch APIs in your application
• Set the various configuration options using the touch_config_at32uc3l.h file.
• Initialize and configure the sensors in the Host application.
• The Host application also has to provide the required timing so as to perform
Touch measurement at regular intervals.
e. General application notes
• Ensure that there are no conflicts between the resources used by the Touch
library and the host application
• Ensure that the stack size is adjusted to factor in the stack depth required for the
operation of the touch libraries.
6.3.20 MISRA Compliance Report of QTouch Library for UC3L
This section lists the compliance and deviations for MISRA standards of coding practice for the
UC3L QTouch libraries.
6.3.21 What is covered
The MISRA compliance covers the QTouch library for AT32UC3L devices. The Example projects
and associated code provided is not guaranteed to be MISRA compliant.
6.3.22 Target Environment
Development Environment IAR Embedded Workbench for Atmel AVR32
MISRA Checking software The MISRA C Compliance has been performed for the library
using MISRA C 2004 Rules in IAR Workbench for Atmel AVR32
MISRA Rule set applied MISRAC 2004 Rule Set, All including advisory
6.3.23 Deviations from MISRA C Standards
The QTouch library was subjected to the above mentioned MISRA compliance rules. The
following table lists the exceptions in the AT32UC3L QTouch library source code and also
provides explanation for these exceptions.166 8207L-AT42-05/12
Apart from these, there were many exceptions in the standard header files supplied by the tool
chain and those are not captured here.
Rule Rule Description Advisory/
Required
Exception noted / How it is
addressed
1.1 All code shall conform to ISO 9899
standard C, with no extensions
permitted.
Required This Rule is not supported as the
library implementation requires IAR
extensions like __interrupt. These
intrinsic functions relate to device
hardware functionality, and cannot
practically be avoided.
5.4 A tag name shall be a unique
identifier
Required This is violated as for the reason that
enumerated types are mixed with
other types. This is caused by
integers being assigned to
enumerated types in some places to
save code space
6.3 The basic types of char, int, short,
long, float, and double should not
be used, but specific-length
equivalents should be typedef'd for
the specific compiler, and these
type names used in the code
Advisory The type bool supported by the
compiler violate this rule.
10.3 The value of a complex expression
of integer type shall only be cast to
a type that is not wider and of the
same signedness as the
underlying type of the expression
Required This is required in the code to do
align some pointers in the data block
memory. Cannot be avoided.
11.3 A cast should not be done
between a pointer type and an
integral type
Advisory This is required in the code to do
align some pointers in the data block
memory. Cannot be avoided.
17.4 Array indexing shall be the only
allowed form of pointer arithmetic
Required Pointer increment has been done in
some places for sequential access of
signals, references, etc.
19.13 The # and ## preprocessor
operators should not be used
Advisory This is required for implementation of
a macro for ease of use &
abstraction
6.3.24 Known Issues with QTouch Library for UC3L
• When the IAR Example Project is build, the IAR32 compiler reports the following Warning
- Warning[Pe047]: incompatible redefinition of macro "AVR32_PM_PPCR_MASK"
(declared at line 607 of "C:\Program Files\IAR Systems\Embedded C:\Program Files\IAR
Systems\Embedded Workbench 5.6\avr32\INC\avr32\pm_400.h 467 Workbench
5.6\avr32\INC\avr32/uc3l064.h").
In order to avoid this, this warning (Pe047) has been disabled using the Diagnostics
option in the IAR32 Project.167
6.4 QTouch Library for ATtiny20 device
ATMEL QTouch Library for ATtiny20 can be used for embedding capacitive touch buttons
functionality into ATtiny20 device application.
This Section describes the QTouch Library Application Programming API and Configuration
interface for QTouch method acquisition using the ATtiny20 devices.
6.4.1 Salient Features of QTouch Library for ATtiny20
6.4.1.1 QTouch method sensor
• 1 Physical pin per Touch Button.
• 1 to 5 Touch Buttons can be configured.
• Individual Sensor Threshold, Sensor Hysteresis and Sensor Global acquisition
parameters can be configured.
• Adjacent Key Supression (AKS) support.
• QTouch Studio support for Touch data analysis.
• ‘C’ Programming interface for easy inclusion of User application.
6.4.2 Compiler tool chain support for ATtiny20
The QTouch libraries for ATtiny20 devices are supported for the following compiler tool chains.
Tool Version
IAR Embedded Workbench for Atmel AVR.
IAR Compiler. 5.5
Table 17 Compiler tool chains support for ATtiny20 QTouch Library
6.4.3 Overview of QTouch Library for ATtiny20
For an overview of QTouch method based capacitive touch acquisition, refer Section 5.2.1
QTouch Acquistion method.
The QTouch Library for ATtiny20 device allows for Sensor configuration and Sensor Acquisition
parameter setting. Based on the input Sensor configuration, the QTouch Library takes care of the
capacitive touch acquisition data capture operations on the external capacitive touch sensors.
The captured Touch Data and Touch Button ON/OFF Status information is then available for user
application.
The diagram below indicates a Typical Sensor arrangement using the Tiny20 device. The
QTouch Library uses the ATtiny20 ADC Module to peform capacitive Touch measurements. The
ADC module must be enabled by the Host Application and configured in Free running mode for
QTouch Library to function correctly. The PA0 pin must be configured as Output pin and should
be in HIGH state before the qt_measure_sensors API is called. Port pins PA1 to PA7 can be
used to support upto 5 Touch Buttons. The Touch Buttons must be connected to sequential Port
pins. However, it is not necessary to start the first Touch Button on Port pin PA1. For Example,
when 3 Touch Buttons are required, they can by connected to pins PA5, PA6 and PA7.
The Sensor numbering is always in the increasing order of Port pin.168 8207L-AT42-05/12
Figure 48 Schematic overview of QTouch on Tiny20
6.4.4 API Flow diagram for ATtiny20
For the QTouch Libraries, the timing information is provided by the Host Application by updating
the ‘time_current_ms’ variable in the Timer ISR. The QTouch Library uses this variable to
calculate the necessary timing for Max ON Duration, Drift and Recalibration functionality. Before
using the QTouch Libraries, the Timer ISR must be configured appropriately. Also, the Timer
Interrupt is used to update the ‘time_to_measure_touch’ variable inorder to start a capacitive
touch measurement. It is recommended to call qt_measure_sensors within 100ms each time to
avoid error in QTouch Library timing.
The touch_config_tiny20.h configuration header file can be used to set the desired number of
Touch Sensors (Buttons) as well as individual sensor Threshold, Hysteresis and Recalibration
parameters. The Sensor Global Configuration parameters must be specified using the IAR Linker
define options.
Figure 49 Linker configuration options for Tiny20
ATtiny20
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
1Kohm
1Kohm
1Kohm
1Kohm
1Kohm
Touch Button 1
Touch Button 2
Touch Button 3
Touch Button 4
Touch Button 5
VCC
No Connection
GND169
Figure 50 QTouch method for Tiny20 API Flow diagram
6.4.5 QTouch Library configuration parameters for ATtiny20
The Table below describes the various configuration parameters corresponding to the ATtiny20.
qt_init_sensing()
Setup the desired device clock using the init_system() in main.c
Using the init_timer(), setup the Timer ISR such that the Timer Interrupt occurs every
20ms . Enable the ADC and configure in Free running mode.
Using the touch_config_tiny20.h configuration file,
1. Set the desired number of Sensors.
2. Set the Individual sensor Threshold, Hysteresis, Recalibration Threshold and Delay
cycle values.
3. Set the desired Sensor Global acquisition parameters using the
IAR Project->Linker options.
4. The DEF_QT_ADC_CHANNEL_START_INDEX Linker option can be used to set
the starting ADC Channel.
Add any Host Application
(a Sample LED application is available with the Tin20 EK IAR Example project).
qt_measure_sensors()
Call in loop
time_to_
measure_touch
Measured data and Touch Status
Host Application code170 8207L-AT42-05/12
Parameter Description
DEF_QT_QDEBUG_ENABLE Enable/Disable QDebug debug data communication to QTouch
Studio.
DEF_QT_NUM_SENSORS QTouch number of Sensors. Range: 1u to 5u.
DEF_QT_SENSOR_0_THRESHOLD,
DEF_QT_SENSOR_1_THRESHOLD,
DEF_QT_SENSOR_2_THRESHOLD,
DEF_QT_SENSOR_3_THRESHOLD,
DEF_QT_SENSOR_4_THRESHOLD
Sensor detection threshold value.
Range: 1u to 255u.
DEF_QT_SENSOR_0_HYSTERESIS,
DEF_QT_SENSOR_1_HYSTERESIS,
DEF_QT_SENSOR_2_HYSTERESIS,
DEF_QT_SENSOR_3_HYSTERESIS,
DEF_QT_SENSOR_4_HYSTERESIS
Sensor detection hysteresis value. Refer hysteresis_t in
touch_api_tiny20.h
HYST_50 = (50% of Sensor detection threshold value)
HYST_25 = (25% of Sensor detection threshold value)
HYST_12_5 = (12.5% of Sensor detection threshold value)
HYST_6_25 = (6.25%, but value is hardlimited to 2)
DEF_QT_SENSOR_0_RECAL_THRESHOLD,
DEF_QT_SENSOR_1_RECAL_THRESHOLD,
DEF_QT_SENSOR_2_RECAL_THRESHOLD,
DEF_QT_SENSOR_3_RECAL_THRESHOLD,
DEF_QT_SENSOR_4_RECAL_THRESHOLD
Sensor recalibration threshold value. Refer recal_threshold_t in
touch_api_tiny20.h
RECAL_100 = (100% of Sensor detection threshold value)
RECAL_50 = (50% of Sensor detection threshold value)
RECAL_25 = (25% of Sensor detection threshold value)
RECAL_12_5 = (12.5% of Sensor detection threshold value)
RECAL_6_25 = (6.25%, but value is hardlimited to 4)
DEF_QT_DELAY_CYCLES Delay cycles that determine the capacitance charge transfer time.
Range: 1, 2, 4, 8 or 10 internal System Clock cycles.
DEF_QT_ADC_CHANNEL_START_INDEX ADC Channel starting index. Range: 1u to 7u.
DEF_QT_AKS_ENABLE Enable/Disable Adjacent Key suppression (AKS) on all channels.
DEF_QT_DI Sensor detect integration (DI) limit.Range: 0u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_NEG_DRIFT_RATE*(See Note 1) Sensor negative drift rate. Units: 100ms, Range: 1u to 127u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_POS_DRIFT_RATE*(See Note 1) Sensor positive drift rate. Units: 100ms, Range: 1u to 127u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_MAX_ON_DURATION Sensor maximum on duration. Units: 100ms, Range: 0u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_DRIFT_HOLD_TIME Sensor drift hold time. Units: 100ms, Range: 1u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_POS_RECAL_DELAY Positive Recalibration delay. Range: 1u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_NUM_SENSORS_SYM QTouch number of Sensors Symbol for QTouch Library.
MUST be the same as DEF_QT_NUM_SENSORS.
DEF_QT_BURST_LENGTH
Specifies the no:of burst sequence required for a sensor. Multiple
burst for adjusting sensitivity by increasing the resolution of the Signal
measured.Use higher value for increasing sensitivity.
Values: 1u, 4u and 16u, 32u. With a setting of 32u, the Touch
Response time would be sluggish.
DEF_CHARGE_SHARE_DELAY
Defines the Charging Share Delay time as an additional Number of
CPU Cycles delay to be introduced during the Charge transfer.
Values:0 to 255.
Table 18 QTouch Library for ATtiny20 Configuration parameters171
Note1:
For the case of ATtiny20 devices, a ‘touch’ causes the Signal value measured on the Sensor to
increase above the Sensor Reference value (In the case of Generic Library devices, a ‘touch’
causes the Signal value to decrease below the Reference value).
However, the Negative drift rate and Positive drift rate functionality for the case of Tiny20 devices
shall be consistent with the Generic Library case.
So, it is recommended to have a ‘Slower’ Negative Drift rate (4 seconds is the default setting) and
a ‘Faster’ Positive Drift rate (1 second is the default setting) for the Tiny20 device.
6.4.6 QTouch Library ATtiny20 Example projects
The QTouch method IAR Example project for the Tiny20 Evaluation Kit can be found in the
following path.
\Device_Specific_Libraries\8bit_AVR\AVR_Tiny_Mega_XMega\ATtiny20\
tiny20_ek_iar_qt_example
The Example projects demonstrate the 5 button sensor configuration with a Sample LED
application. The Example projects also support QDebug data transfer to QTouch Studio – Touch
Analyzer PC Application.
It is possible to configure the number of Sensors in the Example project from 1 to 5 for testing on
the ATtiny20 Evaluation kit.
6.4.7 QTouch Library ATtiny20 code and data memory requirements
The code and data memory requirements for QTouch Library for ATtiny20 devices is captured in
the Table below. The Table indicates these values for the standalone library and not for the
entire Example Project application.
Library Number of
Sensors
Code Memory Data
memory
CStack/RStack
libtiny20-5qt-k-
0rs 5 1231 + 15 bytes
Const data 70
CStack= 0x1C bytes
RStack= 10
(16 bytes) is the
Recommended setting.
libtiny20-5qt-k-
0rs 4 1231 + 12 bytes
Const data 60
CStack= 0x1C bytes
RStack= 10
(16 bytes) is the
Recommended setting.
libtiny20-5qt-k-
0rs 3 1231 + 9 bytes
Const data 50
CStack= 0x1C bytes
RStack= 10
(16 bytes) is the
Recommended setting.
libtiny20-5qt-k-
0rs 2 1231+ 6 bytes
Const data 40
CStack= 0x1C bytes
RStack= 10
(16 bytes) is the
Recommended setting.
libtiny20-5qt-k-
0rs
1 1231 + 3 bytes
Const data 30
CStack= 0x1C bytes
RStack= 10
(16 bytes) is the
Recommended setting.
Table 19 QTouch Library for ATtiny20 Memory requirements172 8207L-AT42-05/12
Data memory for ATtiny20 QTouch Library include the following.
10. QTouch Library data memory – 19 bytes, allocated inside the Library.
11. channel_signals – 2 bytes per Sensor, allocated in main.c
12. channel_references – 2 bytes per Sensor, allocated in main.c
13. sensor_delta – 2 bytes per Sensor, allocated in main.c
14. sensor_general_counter – 2 bytes per Sensor, allocated in main.c
15. sensor_state – 1 byte per Sensor, allocated in main.c
16. sensor_ndil_counter – 1 byte per Sensor, allocated in main.c
17. sensor_states – 1 byte, allocated in main.c
Const Data memory for ATtiny20 QTouch Library include the following.
1. sensor_threshold, 1 byte per Sensor, allocated in main.c
2. sensor_hyst_threshold, 1 byte per Sensor, allocated in main.c
3. sensor_recal_threshold, 1 byte per Sensor, allocated in main.c
6.5 QTouch Library for ATtiny40 device
ATMEL QTouch Library for ATtiny40 can be used for embedding capacitive touch buttons
functionality into ATtiny40 device application.
This Section describes the QTouch Library Application Programming API and Configuration
interface for QTouch method acquisition using the ATtiny40 devices.
6.5.1 Salient Features of QTouch Library for ATtiny40
6.5.1.1 QTouch method sensor
• One Physical pin per Touch Button.
• 1 to 12 Touch Buttons can be configured.
• Individual Sensor Threshold, Sensor Hysteresis and Sensor Global acquisition
parameters can be configured.
• Signal resolution can be configured.
• Charge Share Delay can be configured.
• Adjacent Key Supression (AKS) support.
• QTouch Studio support for Touch data analysis.
• ‘C’ Programming interface for easy inclusion of User application.173
6.5.2 Compiler tool chain support for ATtiny40
The QTouch libraries for ATtiny40 devices are supported for the following compiler tool chains.
Tool Version
IAR Embedded Workbench for Atmel AVR.
IAR Compiler. 6.10
Table 20 Compiler tool chains support for ATtiny40 QTouch Library
6.5.3 Overview of QTouch Library for ATtiny40
For an overview of QTouch method based capacitive touch acquisition, refer Section 5.2.1
QTouch Acquistion method.
The QTouch Library for ATtiny40 device allows for Sensor configuration and Sensor Acquisition
parameter setting. Based on the input Sensor configuration, the QTouch Library takes care of the
capacitive touch acquisition data capture operations on the external capacitive touch sensors.
The captured Touch Data and Touch Button ON/OFF Status information is then available for user
application.
The diagram below indicates a Typical Sensor arrangement using the Tiny40 device. For one
channel configuration, two ADC pins are used for acquisition. For number of touch buttons
greater than one, no extra ADC pins are used. Port pins PA0 to PA7 and PB0 to PB3 can be
used to support upto 12 Touch Buttons. The Touch Buttons may be connected anywhere on the
said port pins.
The Sensor numbering is always in the increasing order of Port pin.
Figure 51 Schematic overview of QTouch on Tiny40
ATtiny40
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
1Kohm
Touch Button 1
VCC
GND
Touch Button 0
PB0
PB1
PB2
PB3
1Kohm
1Kohm
Touch Button 3
Touch Button 2
1Kohm
Touch Button 5
Touch Button 4
1Kohm
1Kohm
Touch Button 7
Touch Button 6
1Kohm
Touch Button 9
Touch Button 8
1Kohm
1Kohm
Touch Button 11
Touch Button 10
1Kohm
1Kohm
1Kohm174 8207L-AT42-05/12
6.5.4 API Flow diagram for ATtiny40
For the QTouch Libraries, the timing information is provided by the Host Application by updating
the ‘time_current_ms’ variable in the Timer ISR. The QTouch Library uses this variable to
calculate the necessary timing for Max ON Duration, Drift and Recalibration functionality. Before
using the QTouch Libraries, the Timer ISR must be configured appropriately. Also, the Timer
Interrupt is used to update the ‘time_to_measure_touch’ variable inorder to start a capacitive
touch measurement.
The touch_config_dp.h configuration header file must be used to set the number of channels
based on the library used. For example, if the library used is a 12 channel library then
QT_NUM_CHANNELS must be specified as 12 in the touch_config_dp.h. This information must
be provided irrespective of the number of channels actually used.
The desired number of touch buttons used can be enabled using the qt_enable_key() routine.
The channel numbers are sequential from Port A through Port B. Also, individual sensor
Threshold, Hysteresis, AKS group and Recalibration parameters can be set using this function
call. The Sensor Global Configuration parameters can also be set by the user by directly
accessing the global configuration data structure.
When developing a Host application for ATtiny40 device, ensure that the ADC prescalar is set in
such a way that it is in the range of 50 KHz to 250 KHz. For example, if the main clock is running
at 8MHz then set the ADC prescalar to 32 or more. This must be done to ensure proper touch
sensing acquisition.175
Figure 52 QTouch method for Tiny40 API Flow diagram
6.5.5 QTouch Library configuration parameters for ATtiny40
The Table below describes the various configuration parameters corresponding to the ATtiny40
QTouch Library.176 8207L-AT42-05/12
Parameter Description
DEF_QT_DI Sensor detect integration (DI) limit.Range: 0u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_NEG_DRIFT_RATE*(See Note 1) Sensor negative drift rate. Units: 100ms, Range: 1u to 127u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_POS_DRIFT_RATE*(See Note 1) Sensor positive drift rate. Units: 100ms, Range: 1u to 127u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_MAX_ON_DURATION Sensor maximum on duration. Units: 100ms, Range: 0u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_DRIFT_HOLD_TIME Sensor drift hold time. Units: 100ms, Range: 1u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_RECAL_THRESHOLD
• Setting of 0 = 100% of detect threshold
• Setting of 1 = 50% of detect threshold
• Setting of 2 = 25% of detect threshold
• Setting of 3 = 12.5% of detect threshold
• Setting of 4 = 6.25% of detect threshold
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_POS_RECAL_DELAY Positive Recalibration delay. Range: 1u to 255u.
Refer Section 5.3 and Section 5.4 for more info.
DEF_QT_PULSE_SCALE
Default value is 0x0 means 1 oversamples and scaling/averaging
factor 1.
Refer Note on using Pulse Scale Value:
DEF_QT_CHARGE_SHARE_DELAY
Charge Share Delay. Range: 1u – 255u. This value needs to be
increased if we use high value of series resistor on sensor pin to
ensure proper charge time.
Table 21 QTouch Library for ATtiny40 Configuration parameters
Note1:
For the case of ATtiny40 devices, a ‘touch’ causes the Signal value measured on the Sensor to
increase above the Sensor Reference value (In the case of Generic Library devices, a ‘touch’
causes the Signal value to decrease below the Reference value).
However, the Negative drift rate and Positive drift rate functionality for the case of Tiny40 devices
shall be consistent with the Generic Library case.
So, it is recommended to have a ‘Slower’ Negative Drift rate (4 seconds is the default setting) and
a ‘Faster’ Positive Drift rate (1 second is the default setting) for the Tiny40 device.
Note on using Pulse Scale Value:
This variable is used to increase the resolution of the signal. qt_pulse_scale variable is available
to change the oversampling and scaling factor.This is available for all the channels and now with
this one should increase the gain for each channel individually.
Function set_qt_pulse_scale is provided in main.c file for reference which will change the values
of pulse scale variable.
This variable is divided into higher(pulse/oversamples) and lower(scaling/averaging) nibble.The
higher nibble corresponds to number of oversamples and lower nibble corresponds to
scaling/averaging. The Pulse value is the power of 2 number of pulses which will accumulate their
results.The Scale value is the power of 2 number which will divide the accumulated result from
the pulse measurements.
The maximum value of higher nibble possible is 0xA and maximum value of lower nibble is 0xA.177
Consideration should be taken on the overall effect on timing when setting Pulse values.
A high gain setting will add considerably time taken to acquire all channels.
6.5.6 QTouch Library ATtiny40 Example projects
The QTouch method IAR Example project for the Tiny40 Evaluation Kit can be found in the
following path.
\Device_Specific_Libraries\8bit_AVR\AVR_Tiny_Mega_XMega\ATtiny40\tiny40_qt_example_iar
The Example projects demonstrate the 12 button sensor configuration. The Example projects
also support QDebug data transfer to QTouch Studio – Touch Analyzer PC Application.
It is possible to configure the number of Sensors in the Example project from 1 to 12 for testing
on the ATtiny40 Evaluation kit.
6.5.7 QTouch Library ATtiny40 code and data memory requirements
The code and data memory requirements for QTouch Library for ATtiny40 devices is captured in
the Table below. The Table indicates these values for the standalone library and not for the
entire Example Project application.
Library Number of
Sensors
Code Memory Data
memory
CStack/RStack
libtiny40_4qt_k_0rs 4 2400 149 CStack= 40 bytes
RStack= 24 bytes
libtiny40_8qt_k_0rs 8 2400 193 CStack= 40 bytes
RStack= 24 bytes
libtiny40_12qt_k_0rs 12 2500 235 CStack= 40 bytes
RStack= 24 bytes
Table 22 QTouch Library for ATtiny40 Memory requirements
6.5.8 Interrupt Handling in QTouch ADC
In case of ATtiny40, the Interrupts are disabled for each acquisition sample means once per
charge transfers cycle and typically this is 1184 Instruction cycles.
Depending on number of oversamples and channels, the total number of times the interrupts are
disabled will vary.
Total number of times interrupts disabled = No of oversamples * No of channels.
The Touch measurement will not be affected by longer ISR execution, only the response time will
get affected.
The acquisition time is a lot more predictable since a fixed amount of pulses/oversamples are
used. The time to execute one measurement will depend on various software parameters like no
of oversamples, Charge share delay and CPU Frequency.
For one button to execute with following below parameters, QTouch ADC takes around 0.7
msec.
CPU Freq=4 MHZ, Number of oversamples=1, Charge Share Delay =1.178 8207L-AT42-05/12
7 Generic QTouch Libraries for 2K Devices
7.1 Introduction
This section provides information about the QTouch library Acquisition Support for Tiny devices
with 2K Flash memory. These libraries have the same API’s as Generic libraries, except for a few
which are not supported.Information about the API’s are provided in touch_api_2kdevice.h file
which is placed at location mentioned in section 5.6.10.1
7.2 Devices supported
The list of different devices that are supported by the QTouch library for 2K devices is given
below:
1. ATtiny2313A
2. ATtiny261A
3. ATtiny24A
4. ATtiny25A
Complete information is available in Library_Selection_Guide.xls.
7.3 Salient Features of QTouch Library for 2K Devices
• 1 to 4 Touch Buttons can be configured. Supports maximum of 4 Buttons.
• Libraries in variants of 1, 2 and 4 channels are provided.
• 2K device libraries are supported only for IAR.
• Library API’s are same as Generic QTouch libraries.
• Support for more than one pair of SNS and SNSK ports are not available for 2K tiny
devices.
NOTE:
No AKS, no Power Optimization and no pin configurability support in case of 2K device
libraries.
The change information like library status flags which reflects if there is any change in
Reference values, rotor slider position change status flags etc are not part of the 2K device
libraries except burst again flag.
7.4 Library Variants
For Different library variants available for 2K Devices, please refer Library_Selection_Guide.xls
7.5 QTouch API for 2K Devices and Usage
This section describes the different API’s used during touch sensing. Using the API, Touch
sensors and the associated channels can be defined. Once touch sensing has been initiated by
the user, the host application can use the API to make touch measurements and determine the
status of the sensors.Refer section 5.6.6 and Figure 5.6 for API usage
7.5.1 touch_api_2kdevice.h - public header file179
The touch_api_2kdevice.h header file is the public header file which needs to be included in
user’s application. The type definitions and function prototypes of the API’s listed in sections 5.6.3
, 5.6.4 and 5.6.5
The touch_api_2kdevice.h header file is located in the library distribution in the following
directory.
• ..\Atmel_QTouch_Libraries_5.x\Generic_QTouch_Libraries\include
The constant/symbol definitions can be placed in any of the following.
Defined user’s project options. All the constants/symbols must be defined for both the
compiler and assembler preprocessing definitions.
As an alternative, it is also declared in the touch_qt_config_2kdevice.h file. The user
may modify these defined values based on the requirements.
Global settings common to all sensors and sensor specific settings are listed in sections 5.3 and
5.4 respectively
7.5.2 Sequence of Operations and Using the API
Figure 5-6 illustrates the sequence of operations required to be performed to add touch to an end
application. By using the simple API’s as illustrated in the sequence flowchart, the user can add
touch sensing in his design.
7.5.2.1 Channel Numbering
• 1-channel library – supports 1 channel using 1 consecutive pins on different SNS and
SNSK ports (or) supports 1 channel using 2 consecutive pins on the same port used for
both SNS and SNSK lines. This library requires 1 or 2 port.
• 2-channel library – supports up to 2 channels using 2 consecutive pins on different SNS
and SNSK ports (or) supports up to 2 channels using 4 consecutive pins on the same
port used for both SNS and SNSK lines. This library requires 1 or 2 ports.
• 4-channel library – supports up to 4 channels using 4 consecutive pins on different SNS
and SNSK ports (or) supports up to 4 channels using 8 consecutive pins on the same
port used for both SNS and SNSK lines. This library requires 1 or 2 ports.
7.5.2.1.1 Channel numbering when routing SNS and SNSK pins to different ports
When SNS and SNSK pins are available on different ports, the channel numbering follows the pin
numbering in the ports selected.
• The channel numbers follow the pin numbers starting with the LSB (pin 0 is channel 0
and pin 3 is channel 3).
• Since the channel numbers are fixed to the pins of the SNS and SNSK ports, if the
design calls for use of a subset of the pins available in the SNS and SNSK ports, the user
has to skip the channel numbers of the unused SNS and SNSK pins.
For example, on a 4 channel configuration using SNS and SNSK ports, if pin 2 is not
used for touch sensing ( on both SNS and SNSK ports), channel number 2 is
unavailable and care should be taken while configuring the channels and sensors to
avoid using this channel. Also, the SNS and SNSK masks are assigned properly as
explained in section 7.5.2.2180 8207L-AT42-05/12
7.5.2.1.2 Channel numbering when routing SNS and SNSK pins to the same port
When SNS and SNSK pins are connected to the same port, the even pin numbers will be used as
SNS pins and the odd pins will be used as the SNSK pins.
• The number of channels supported will be limited 4 channels
• For e.g., for a 4 channel configuration where the SNS and SNSK pins are connected to
Port B, the port pins 0&1 are used for channel 0.
• The channel number is derived from the position of the pins used for SNS and SNSK
lines for any channel.
channel number = floor( [SNS(or SNSK) pin number] / 2 )
o For e.g., pins 4 and 5 are connected to a SNS/SNSK pair and the channel number
associated with the SNS/SNSK pin is 2.
7.5.2.2 Rules For Configuring SNS and SNSK masks for 2K Devices
The libraries internally need SNS_array and SNSK_array masks. These masks need to be
defined under Macro QTOUCH_STUDIO_MASKS as per the following rules given below:
1. In case of Interport, SNS_array[0] and SNSK_array[0] mask is used for configuring the
Channel0 and Channel2.And SNS_array[1] and SNSK_array[1] mask is used for configuring the
Channel1 and Channel3.And In case of Intraport SNS_array[0] and SNSK-array[0] are used for
all the four channels configured based on enabled bits in SNS_array[0] and SNSK-array[0].
2. The channel numbers are allocated based on enabled SNS pins starting from LSBBit.
In case of Interport, Keys on adjacent channels should be placed on different masks. Channel0
and Channel1 should be on different SNS/SNSK masks ie channel0 on
SNS_array[0]/SNSK_array[0] and channel1 on SNS_array[1]/ SNSK_array[1].
But in case of Intraport, Keys on adjacent channels should be placed on same masks. Channel0
and Channel2 should be on same mask ie SNS_array[0]/SNSK_array[0] and Channel1 and
Channel3 on SNS_array[1]/ SNSK_array[1].
7.5.2.2.1 Configuring SNS and SNSK masks in case of Interport:
1. Enable the Bit0 in SNS_array[0] and Bit0 in SNSK_array[0] mask when enabling Channel0.
2. Enable the Bit1 in SNS_array[1] and Bit1 in SNSK_array[1] mask when enabling Channel1.
3. Enable the Bit2 in SNS_array[0] and Bit2 in SNSK_array[0] mask when enabling Channel2.
4. Enable the Bit3 in SNS_array[1] and Bit3 in SNSK_array[1] mask when enabling Channel3.
Example 1:
In a 4 channel library, two keys on channel 0 and 3 are enabled.SNS on Port A and SNSK on
Port B .Channel0 will A0B0 and Channel3 will be A3B3.
The SNS and SNSK masks will be
SNS_array[0]=0x01;
SNS_array[1]=0x08;
SNSK_array[0]=0x01;
SNSK_array[1]=0x08;181
7.5.2.2.2 Configuring SNS and SNSK masks in case of Intraport:
1. Enable the Bit0 in SNS_array[0] and Bit1 in SNSK_array[0] mask when enabling Channel0.
2. Enable the Bit2 in SNS_array[0] and Bit3 in SNSK_array[0] mask when enabling Channel1.
3. Enable the Bit4 in SNS_array[0] and Bit5 in SNSK_array[0] mask when enabling Channel2.
4. Enable the Bit6 in SNS_array[0] and Bit7 in SNSK_array[0] mask when enabling Channel3.
Example 1:
In a 4 channel library, two keys on channel 0 and 3 are enabled.SNS and SNSK on Port B
.Channel0 will B0B1 and Channel3 will be B6B7.
The SNS and SNSK masks will be
SNS_array[0]=0x41;
SNS_array[1]=0x00;
SNSK_array[0]=0x82;
SNSK_array[1]=0x00;
7.5.3 Integrating QTouch libraries for 2K Devices in your application
In order to Integrate QTouch libraries for 2K devices, the constants and symbol names listed in
Table 1 below need to be defined in the user application. These can be defined in either the
compiler/assembler preprocessing definitions or in the touch_t_config_2kdegice.h file. Example
projects are provided for all the four devices supported.Refer 5.6.10.1 for directory structure of all
the files.
Table 1: Constant and symbol name definitions required to use the QTouch
acquisition method libraries for 2K device libraries
Symbol / Constant name Range of values Comments
_QTOUCH_ This macro has to be defined in order to
use QTouch libraries.
SNS & SNSK Refer to library selection guide.
_SNS_SNSK_SAME_PORT_ Comment/uncomment define To be enabled if the
same port is used for
SNSK and SNS pins
for QTouch. If SNSK
and SNS pins are on
different ports then
this definition is not
required.
QT_NUM_CHANNELS 1, 2 and 4 for 2K device libraries.
QT_DELAY_CYCLES 1 to 255 Please refer to section
5.6.8.
QTOUCH_STUDIO_MASKS This macro has to be defined in order to
use QTouch libraries for 2K devices.
SNS_array and
SNSK_array masks
variablesare initialized
under this Macro in
main file.Refer section
7.5.2.2182 8207L-AT42-05/12
The following files are to be added along with the touch library and user application
before compilation:
• For ATtiny 2K devices - touch_api_2kdevice.h, touch_qt_config_2kdevice.h and
qt_asm_tiny_mega_2kdevice.S
7.6 MISRA Compliance Report
This section lists the compliance and deviations for MISRA standards of coding practice for the
QTouch acquisition method libraries for 2K devices
7.6.1 What is covered
The QTouch acquisition method libraries for 2K devices adhere to the MISRA standards. The
additional reference code provided in the form of sample applications is not guaranteed to be
MISRA compliant.
7.6.2 Target Environment
Development Environment IAR Embedded Workbench
MISRA Checking software The MISRA C Compliance has been performed for the library
using MISRA C 2004 Rules in IAR Workbench development
environment.
MISRA Rule set applied MISRAC 2004 Rule Set
7.6.3 Deviations from MISRA C Standards
7.6.3.1 QTouch acquisition method libraries for 2K devices
The QTouch acquisition method libraries were subject to the above mentioned MISRA
compliance rules. The following exceptions have not been fixed as they are required for the
implementation of the library.
Applicable
Release
QTouch libraries
Rule No Rule Description Exception noted / How it is addressed
1.1 Rule states that all code
shall conform to ISO 9899
standard C, with no
extensions permitted.
This Rule is not supported as the library
implementation requires IAR extensions like
__interrupt. These intrinsic functions relate to
device hardware functionality, and cannot
practically be avoided.
10.1 Rule states that implicit
conversion from Underlying
long to unsigned long
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
10.6 This Rule says that a 'U'
suffix shall be applied to all
constants of 'unsigned' type
The library uses macros to combine symbol
definitions to form a unique expanded symbol
name and in this, the usage of unsigned qualifiers
for numeric constants (e.g. 98u) causes name
mangling. This is the only occurrence of this error
in the library.
14.4 Rule states that go-to
statement should not be
The library uses conditional jump instructions to
reduce the code footprint at a few locations and 183
used. this is localized to small snippets of code. Hence
this rule is not supported.
19.10
Rule states that In the
definition of a function-like
macro, each instance of a
parameter shall be enclosed
in parenthesis
There is one instance where the library breaks this
rule where two macro definitions are combined to
form a different symbol name. Usage of
parenthesis cannot be used in this scenario.
19.12 Rule states that there shall
be at most one occurrence
of the # or ## preprocessor
operator in a single macro
definition
There is one instance in the library where this rule
is violated where the library concatenates two
macro definitions to arrive at a different definition.
8 Revision History
The table below lists the revision history for chapters in the user guide.
QTouch Library User guide Revision History
Date/Version Chapter Change notes
May 2009
Ver2.0
All 2nd release of QTouch library users guide
Sep 2009
Ver. 3.0
All Re-structured user guide with new and expanded sections
Nov 2009
Ver. 3.1
6.3, 6.9, 6.10,
7, 10
• Updated API changes
• Updated new libraries and device support information
• Updated debug interface information supported by the
QTouch libraries
• Updated known issues table
Dec 2009
Ver. 3.2
6.10.4, 7.1.2,
7.1.5, 7.1.6,
10,
7.2.4.2.2,
7.2.4.3.7,
7.2.4.3.2,
7.2.4.3.5,
7.2.4.3.7,
• Added section about configuring unused pins in user
application
• Added more information to some sections to clear
ambiguity
• Updated Memory footprint information for IAR and GCC
compiled QTouch libraries.
• Updated known issues table
• Added the device support, port combinations, memory
requirements
• QMatrix IAR and GCC libraries to support ATmega325P,
ATmega645, and ATtiny167.
• Modified port combinations for the 165P for QMatrix
libraries.
• Few Port combinations added in case of ATmega88
libraries.
Feb 2010
Ver 4.0
All chapters
changed
• A separate library selection guide is provided external to
the user guide. All sections included in the library selection
guide have been removed from the user guide.
• All sections have been updated to account for the improved
configurability of the libraries.
Apr 2010
Ver 4.1
• Added sections related to Positive Recalibration Delay,
Position Hysteresis, and Position Resolution. 184 8207L-AT42-05/12
• Device support extended for QMatrix for the release has
been added in section 5.7.2.4.1 and 5.7.2.3
• In case of QMatrix, 4 ( 4x1) channel has been added
wherever needed and in case of ATxmega devices 56
(8x7) channel has been added according to the changes
• QTouch Library for UC3L API Device Specific Libraries
Section has been added.
May 2010
Ver 4.2
• Qtouch acquisition libraries support will be available for
ATSAM3U and ATSAM3S devices.
• Qdebug protocol support will be extended for all example
projects.
• Analog comparator usage and burst length setting
recommendation Note added for UC3L QMatrix method.
• QMatrix device support added for AT90USB82 / 162 / 646 /
647 / 1286
July 2010
Ver 4.3
Section 5.8,
Section 5.7.2.4
• Device support added for Tiny44/84/461/861
• Added the details on Pin configuration support for both
QTouch and QMatrix libraries.
• Added section related to the usage of the pin configurator
tool on QTouch Studio.(section 5.8)
• Added sections for Tiny20 and Tiny40 Devices.
Jan 2011
Ver 4.3.1
Chapter 7,
Section
5.6.11.2.1,
Section
5.7.11.2.1
• Device support added for QTouch 2K devices
ATtiny2313A/261A/24A/25A.
• Added Chapter 7 on 2K Device libraries.
• QTouch Support added for UC3C family devices.
• QTouch Support added for ATtiny87 device
• Tiny20 code memory requirement section updated.
Aug 2011
Ver 4.4
Chapter 2
Section
5.6.10.3
Section 6.5
Section 5.5.3
• Added Feature Comparison Table
• Section 5.6.10 changed and updated for Support for
QMatrix AT32UC3C0512 Device
• Section 6.5 changed and updated for ATtiny40 libraries
• Section 5.5.3 added for Guard Channel
April 2012
Ver 5.0
Section 6.5.5
Section 6.5.8
• Section 6.5.5 changed and updated for ATtiny40 libraries
• Section 6.5.8 changed and updated for ATtiny40 libraries
• Section 5.6.10.3.1 changed and updated for 8-bit Qmatrix
libraries related to Shared YA/YB.
• Sections 5.6.10.1, 5.6.10.2, 5.7.1.2, 5.7.1.3.1 updated for
sam4s addition185
Disclaimer
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others.
2586Q–AVR–08/2013
Features
• High Performance, Low Power AVR® 8-Bit Microcontroller
• Advanced RISC Architecture
– 120 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
• Non-volatile Program and Data Memories
– 2/4/8K Bytes of In-System Programmable Program Memory Flash
• Endurance: 10,000 Write/Erase Cycles
– 128/256/512 Bytes In-System Programmable EEPROM
• Endurance: 100,000 Write/Erase Cycles
– 128/256/512 Bytes Internal SRAM
– Programming Lock for Self-Programming Flash Program and EEPROM Data Security
• Peripheral Features
– 8-bit Timer/Counter with Prescaler and Two PWM Channels
– 8-bit High Speed Timer/Counter with Separate Prescaler
• 2 High Frequency PWM Outputs with Separate Output Compare Registers
• Programmable Dead Time Generator
– USI – Universal Serial Interface with Start Condition Detector
– 10-bit ADC
• 4 Single Ended Channels
• 2 Differential ADC Channel Pairs with Programmable Gain (1x, 20x)
• Temperature Measurement
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
• Special Microcontroller Features
– debugWIRE On-chip Debug System
– In-System Programmable via SPI Port
– External and Internal Interrupt Sources
– Low Power Idle, ADC Noise Reduction, and Power-down Modes
– Enhanced Power-on Reset Circuit
– Programmable Brown-out Detection Circuit
– Internal Calibrated Oscillator
• I/O and Packages
– Six Programmable I/O Lines
– 8-pin PDIP, 8-pin SOIC, 20-pad QFN/MLF, and 8-pin TSSOP (only ATtiny45/V)
• Operating Voltage
– 1.8 - 5.5V for ATtiny25V/45V/85V
– 2.7 - 5.5V for ATtiny25/45/85
• Speed Grade
– ATtiny25V/45V/85V: 0 – 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V
– ATtiny25/45/85: 0 – 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V
• Industrial Temperature Range
• Low Power Consumption
– Active Mode:
• 1 MHz, 1.8V: 300 µA
– Power-down Mode:
• 0.1 µA at 1.8V
Atmel 8-bit AVR Microcontroller with 2/4/8K
Bytes In-System Programmable Flash
ATtiny25/V / ATtiny45/V / ATtiny85/V
Rev. 2586Q–AVR–08/2013ATtiny25/45/85 [DATASHEET] 2
2586Q–AVR–08/2013
1. Pin Configurations
Figure 1-1. Pinout ATtiny25/45/85
1.1 Pin Descriptions
1.1.1 VCC
Supply voltage.
1.1.2 GND
Ground.
1.1.3 Port B (PB5:PB0)
Port B is a 6-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port B output buffers
have symmetrical drive characteristics with both high sink and source capability. As inputs, Port B pins that are
externally pulled low will source current if the pull-up resistors are activated. The Port B pins are tri-stated when a
reset condition becomes active, even if the clock is not running.
1
2
3
4
8
7
6
5
(PCINT5/RESET/ADC0/dW) PB5
(PCINT3/XTAL1/CLKI/OC1B/ADC3) PB3
(PCINT4/XTAL2/CLKO/OC1B/ADC2) PB4
GND
VCC
PB2 (SCK/USCK/SCL/ADC1/T0/INT0/PCINT2)
PB1 (MISO/DO/AIN1/OC0B/OC1A/PCINT1)
PB0 (MOSI/DI/SDA/AIN0/OC0A/OC1A/AREF/PCINT0)
PDIP/SOIC/TSSOP
1
2
3
4
5
QFN/MLF
15
14
13
12
11
20
19
18
17
16
6
7
8
9
10
DNC
DNC
GND
DNC
DNC
DNC
DNC
DNC
DNC
DNC
NOTE: Bottom pad should be soldered to ground.
DNC: Do Not Connect
NOTE: TSSOP only for ATtiny45/V
(PCINT5/RESET/ADC0/dW) PB5
(PCINT3/XTAL1/CLKI/OC1B/ADC3) PB3
DNC
DNC
(PCINT4/XTAL2/CLKO/OC1B/ADC2) PB4
VCC
PB2 (SCK/USCK/SCL/ADC1/T0/INT0/PCINT2)
DNC
PB1 (MISO/DO/AIN1/OC0B/OC1A/PCINT1)
PB0 (MOSI/DI/SDA/AIN0/OC0A/OC1A/AREF/PCINT0)ATtiny25/45/85 [DATASHEET] 3
2586Q–AVR–08/2013
Port B also serves the functions of various special features of the ATtiny25/45/85 as listed in “Alternate Functions
of Port B” on page 60.
On ATtiny25, the programmable I/O ports PB3 and PB4 (pins 2 and 3) are exchanged in ATtiny15 Compatibility
Mode for supporting the backward compatibility with ATtiny15.
1.1.4 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 21-4
on page 165. Shorter pulses are not guaranteed to generate a reset.
The reset pin can also be used as a (weak) I/O pin.ATtiny25/45/85 [DATASHEET] 4
2586Q–AVR–08/2013
2. Overview
The ATtiny25/45/85 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By
executing powerful instructions in a single clock cycle, the ATtiny25/45/85 achieves throughputs approaching 1
MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
2.1 Block Diagram
Figure 2-1. Block Diagram
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 one
single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving
throughputs up to ten times faster than conventional CISC microcontrollers.
PROGRAM
COUNTER
CALIBRATED
INTERNAL
OSCILLATOR
WATCHDOG
TIMER
STACK
POINTER
PROGRAM
FLASH SRAM
MCU CONTROL
REGISTER
GENERAL
PURPOSE
REGISTERS
INSTRUCTION
REGISTER
TIMER/
COUNTER0
SERIAL
UNIVERSAL
INTERFACE
TIMER/
COUNTER1
INSTRUCTION
DECODER
DATA DIR.
REG.PORT B
DATA REGISTER
PORT B
PROGRAMMING
LOGIC
TIMING AND
CONTROL
MCU STATUS
REGISTER
STATUS
REGISTER
ALU
PORT B DRIVERS
PB[0:5]
VCC
GND
CONTROL
LINES
8-BIT DATABUS
Z
ADC /
ANALOG COMPARATOR
INTERRUPT
UNIT
DATA
EEPROM OSCILLATORS
Y
X
RESETATtiny25/45/85 [DATASHEET] 5
2586Q–AVR–08/2013
The ATtiny25/45/85 provides the following features: 2/4/8K bytes of In-System Programmable Flash, 128/256/512
bytes EEPROM, 128/256/256 bytes SRAM, 6 general purpose I/O lines, 32 general purpose working registers, one
8-bit Timer/Counter with compare modes, one 8-bit high speed Timer/Counter, Universal Serial Interface, Internal
and External Interrupts, a 4-channel, 10-bit ADC, a programmable Watchdog Timer with internal Oscillator, and
three software selectable power saving modes. Idle mode stops the CPU while allowing the SRAM, Timer/Counter,
ADC, Analog Comparator, and Interrupt system to continue functioning. Power-down mode saves the register contents,
disabling all chip functions until the next Interrupt or Hardware Reset. ADC Noise Reduction mode stops the
CPU and all I/O modules except ADC, to minimize switching noise during ADC conversions.
The device is manufactured using Atmel’s high density non-volatile memory technology. The On-chip ISP Flash
allows the Program memory to be re-programmed In-System through an SPI serial interface, by a conventional
non-volatile memory programmer or by an On-chip boot code running on the AVR core.
The ATtiny25/45/85 AVR is supported with a full suite of program and system development tools including: C Compilers,
Macro Assemblers, Program Debugger/Simulators and Evaluation kits.ATtiny25/45/85 [DATASHEET] 6
2586Q–AVR–08/2013
3. About
3.1 Resources
A comprehensive set of development tools, application notes and datasheets are available for download on
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.ATtiny25/45/85 [DATASHEET] 7
2586Q–AVR–08/2013
4. AVR CPU Core
4.1 Introduction
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.
4.2 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 operFlash
Program
Memory
Instruction
Register
Instruction
Decoder
Program
Counter
Control Lines
32 x 8
General
Purpose
Registrers
ALU
Status
and Control
I/O Lines
EEPROM
Data Bus 8-bit
Data
SRAM
Direct Addressing
Indirect Addressing
Interrupt
Unit
Watchdog
Timer
Analog
Comparator
I/O Module 2
I/O Module1
I/O Module nATtiny25/45/85 [DATASHEET] 8
2586Q–AVR–08/2013
ands 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, able to directly address the
whole address space. Most AVR instructions have a single 16-bit word format, but there are also 32-bit
instructions.
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.
4.3 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 the “Instruction Set” section for a detailed description.
4.4 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, as specified in the Instruction Set Reference. This will in many cases
remove the need for using the dedicated compare instructions, resulting in faster and more compact code.
The Status Register is not automatically stored when entering an interrupt routine and restored when returning
from an interrupt. This must be handled by software.ATtiny25/45/85 [DATASHEET] 9
2586Q–AVR–08/2013
4.4.1 SREG – AVR Status Register
The AVR Status Register – SREG – is defined as:
• Bit 7 – I: Global Interrupt Enable
The Global Interrupt Enable bit must be set for the interrupts to be enabled. The individual interrupt enable control
is then performed in separate control registers. If the Global Interrupt Enable Register is cleared, none of the interrupts
are enabled independent of the individual interrupt enable settings. The I-bit is cleared by hardware after an
interrupt has occurred, and is set by the RETI instruction to enable subsequent interrupts. The I-bit can also be set
and cleared by the application with the SEI and CLI instructions, as described in the instruction set reference.
• Bit 6 – T: Bit Copy Storage
The Bit Copy instructions BLD (Bit LoaD) and BST (Bit STore) use the T-bit as source or destination for the operated
bit. A bit from a register in the Register File can be copied into T by the BST instruction, and a bit in T can be
copied into a bit in a register in the Register File by the BLD instruction.
• Bit 5 – H: Half Carry Flag
The Half Carry Flag H indicates a Half Carry in some arithmetic operations. Half Carry is useful in BCD arithmetic.
See the “Instruction Set Description” for detailed information.
• Bit 4 – S: Sign Bit, S = N V
The S-bit is always an exclusive or between the Negative Flag N and the Two’s Complement Overflow Flag V. See
the “Instruction Set Description” for detailed information.
• Bit 3 – V: Two’s Complement Overflow Flag
The Two’s Complement Overflow Flag V supports two’s complement arithmetics. See the “Instruction Set Description”
for detailed information.
• Bit 2 – N: Negative Flag
The Negative Flag N indicates a negative result in an arithmetic or logic operation. See the “Instruction Set
Description” for detailed information.
• Bit 1 – Z: Zero Flag
The Zero Flag Z indicates a zero result in an arithmetic or logic operation. See the “Instruction Set Description” for
detailed information.
• Bit 0 – C: Carry Flag
The Carry Flag C indicates a carry in an arithmetic or logic operation. See the “Instruction Set Description” for
detailed information.
Bit 7 6 5 4 3 2 1 0
0x3F I T H S V N Z C SREG
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 10
2586Q–AVR–08/2013
4.5 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 shows the structure of the 32 general purpose working registers in the CPU.
Figure 4-2. AVR CPU 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.
4.5.1 The X-register, Y-register, and Z-register
The registers R26..R31 have some 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.
7 0 Addr.
R0 0x00
R1 0x01
R2 0x02
…
R13 0x0D
General R14 0x0E
Purpose R15 0x0F
Working R16 0x10
Registers 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 ByteATtiny25/45/85 [DATASHEET] 11
2586Q–AVR–08/2013
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).
4.6 Stack Pointer
The Stack is mainly used for storing temporary data, for storing local variables and for storing return addresses
after interrupts and subroutine calls. The Stack Pointer Register always points to the top of the Stack. Note that the
Stack is implemented as growing from higher memory locations to lower memory locations. This implies that a
Stack PUSH command decreases the Stack Pointer.
The Stack Pointer points to the data SRAM Stack area where the Subroutine and Interrupt Stacks are located. This
Stack space in the data SRAM must be defined by the program before any subroutine calls are executed or interrupts
are enabled. The Stack Pointer must be set to point above 0x60. The Stack Pointer is decremented by one
when data is pushed onto the Stack with the PUSH instruction, and it is decremented by two when the return
address is pushed onto the Stack with subroutine call or interrupt. The Stack Pointer is incremented by one when
data is popped from the Stack with the POP instruction, and it is incremented by two when data is popped from the
Stack with return from subroutine RET or return from interrupt RETI.
The AVR Stack Pointer is implemented as two 8-bit registers in the I/O space. The number of bits actually used is
implementation dependent. Note that the data space in some implementations of the AVR architecture is so small
that only SPL is needed. In this case, the SPH Register will not be present.
4.6.1 SPH and SPL — Stack Pointer Register
4.7 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 XH XL 0
X-register 7 0 7 0
R27 (0x1B) R26 (0x1A)
15 YH YL 0
Y-register 7 0 7 0
R29 (0x1D) R28 (0x1C)
15 ZH ZL 0
Z-register 7 0 7 0
R31 (0x1F) R30 (0x1E)
Bit 15 14 13 12 11 10 9 8
0x3E SP15 SP14 SP13 SP12 SP11 SP10 SP9 SP8 SPH
0x3D SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 SPL
76543210
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value RAMEND RAMEND RAMEND RAMEND RAMEND RAMEND RAMEND RAMEND
Initial Value RAMEND RAMEND RAMEND RAMEND RAMEND RAMEND RAMEND RAMENDATtiny25/45/85 [DATASHEET] 12
2586Q–AVR–08/2013
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
4.8 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 48. 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
clkCPUATtiny25/45/85 [DATASHEET] 13
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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.
When using the SEI instruction to enable interrupts, the instruction following SEI will be executed before any pending
interrupts, as shown in this example.
4.8.1 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
period, the Program Counter is pushed onto the Stack. The vector is normally a jump to the interrupt routine, and
this jump takes three clock cycles. If an interrupt occurs during execution of a multi-cycle instruction, this instruction
is completed before the interrupt is served. If an interrupt occurs when the MCU is in sleep mode, the interrupt execution
response time is increased by four clock cycles. This increase comes in addition to the start-up time from the
selected sleep mode.
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< ; Address 0x000F
...ATtiny25/45/85 [DATASHEET] 50
2586Q–AVR–08/2013
the Start-up Time, the MCU will still wake up, but no interrupt will be generated. The start-up time is defined by the
SUT and CKSEL Fuses as described in “System Clock and Clock Options” on page 23.
If the low level on the interrupt pin is removed before the device has woken up then program execution will not be
diverted to the interrupt service routine but continue from the instruction following the SLEEP command.
9.2.2 Pin Change Interrupt Timing
An example of timing of a pin change interrupt is shown in Figure 9-1.
Figure 9-1. Timing of pin change interrupts
clk
PCINT(0)
pin_lat
pin_sync
pcint_in_(0)
pcint_syn
pcint_setflag
PCIF
PCINT(0)
pin_sync
pcint_syn pin_lat D Q
LE
pcint_setflag
PCIF
clk
clk PCINT(0) in PCMSK(x)
pcint_in_(0) 0
xATtiny25/45/85 [DATASHEET] 51
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9.3 Register Description
9.3.1 MCUCR – MCU Control Register
The External Interrupt Control Register A contains control bits for interrupt sense control.
• Bits 1:0 – ISC0[1:0]: Interrupt Sense Control 0 Bit 1 and Bit 0
The External Interrupt 0 is activated by the external pin INT0 if the SREG I-flag and the corresponding interrupt
mask are set. The level and edges on the external INT0 pin that activate the interrupt are defined in Table 9-2. The
value on the INT0 pin is sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last longer
than one clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If
low level interrupt is selected, the low level must be held until the completion of the currently executing instruction
to generate an interrupt.
9.3.2 GIMSK – General Interrupt Mask Register
• Bits 7, 4:0 – Res: Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and will always read as zero.
• Bit 6 – INT0: External Interrupt Request 0 Enable
When the INT0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the external pin interrupt is
enabled. The Interrupt Sense Control0 bits 1/0 (ISC01 and ISC00) in the MCU Control Register (MCUCR) define
whether the external interrupt is activated on rising and/or falling edge of the INT0 pin or level sensed. Activity on
the pin will cause an interrupt request even if INT0 is configured as an output. The corresponding interrupt of External
Interrupt Request 0 is executed from the INT0 Interrupt Vector.
• Bit 5 – PCIE: Pin Change Interrupt Enable
When the PCIE bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin change interrupt is
enabled. Any change on any enabled PCINT[5:0] pin will cause an interrupt. The corresponding interrupt of Pin
Change Interrupt Request is executed from the PCI Interrupt Vector. PCINT[5:0] pins are enabled individually by
the PCMSK0 Register.
Bit 7 6 5 4 3 2 1 0
0x35 BODS PUD SE SM1 SM0 BODSE ISC01 ISC00 MCUCR
Read/Write R R/W R/W R/W R/W R R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 9-2. Interrupt 0 Sense Control
ISC01 ISC00 Description
0 0 The low level of INT0 generates an interrupt request.
0 1 Any logical change on INT0 generates an interrupt request.
1 0 The falling edge of INT0 generates an interrupt request.
1 1 The rising edge of INT0 generates an interrupt request.
Bit 7 6 5 4 3 2 1 0
0x3B – INT0 PCIE – – – – – GIMSK
Read/Write R R/W R/W R R R R R
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 52
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9.3.3 GIFR – General Interrupt Flag Register
• Bits 7, 4:0 – Res: Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and will always read as zero.
• Bit 6 – INTF0: External Interrupt Flag 0
When an edge or logic change on the INT0 pin triggers an interrupt request, INTF0 becomes set (one). If the I-bit in
SREG and the INT0 bit in GIMSK are set (one), the MCU will jump to the corresponding Interrupt Vector. The flag
is cleared when the interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.
This flag is always cleared when INT0 is configured as a level interrupt.
• Bit 5 – PCIF: Pin Change Interrupt Flag
When a logic change on any PCINT[5:0] pin triggers an interrupt request, PCIF becomes set (one). If the I-bit in
SREG and the PCIE bit in GIMSK are set (one), the MCU will jump to the corresponding Interrupt Vector. The flag
is cleared when the interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.
9.3.4 PCMSK – Pin Change Mask Register
• Bits 7:6 – Res: Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and will always read as zero.
• Bits 5:0 – PCINT[5:0]: Pin Change Enable Mask 5:0
Each PCINT[5:0] bit selects whether pin change interrupt is enabled on the corresponding I/O pin. If PCINT[5:0] is
set and the PCIE bit in GIMSK is set, pin change interrupt is enabled on the corresponding I/O pin. If PCINT[5:0] is
cleared, pin change interrupt on the corresponding I/O pin is disabled.
Bit 7 6 5 4 3 2 1 0
0x3A – INTF0 PCIF – – – – – GIFR
Read/Write R R/W R/W R R R R R
Initial Value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x15 – – PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 PCMSK
Read/Write R R R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 53
2586Q–AVR–08/2013
10. I/O Ports
10.1 Introduction
All AVR ports have true Read-Modify-Write functionality when used as general digital I/O ports. This means that
the direction of one port pin can be changed without unintentionally changing the direction of any other pin with the
SBI and CBI instructions. The same applies when changing drive value (if configured as output) or enabling/disabling
of pull-up resistors (if configured as input). Each output buffer has symmetrical drive characteristics with
both high sink and source capability. The pin driver is strong enough to drive LED displays directly. All port pins
have individually selectable pull-up resistors with a supply-voltage invariant resistance. All I/O pins have protection
diodes to both VCC and Ground as indicated in Figure 10-1. Refer to “Electrical Characteristics” on page 161 for a
complete list of parameters.
Figure 10-1. I/O Pin Equivalent Schematic
All registers and bit references in this section are written in general form. A lower case “x” represents the numbering
letter for the port, and a lower case “n” represents the bit number. However, when using the register or bit
defines in a program, the precise form must be used. For example, PORTB3 for bit no. 3 in Port B, here documented
generally as PORTxn. The physical I/O Registers and bit locations are listed in “Register Description” on
page 64.
Three I/O memory address locations are allocated for each port, one each for the Data Register – PORTx, Data
Direction Register – DDRx, and the Port Input Pins – PINx. The Port Input Pins I/O location is read only, while the
Data Register and the Data Direction Register are read/write. However, writing a logic one to a bit in the PINx Register,
will result in a toggle in the corresponding bit in the Data Register. In addition, the Pull-up Disable – PUD bit
in MCUCR disables the pull-up function for all pins in all ports when set.
Using the I/O port as General Digital I/O is described in “Ports as General Digital I/O” on page 53. Most port pins
are multiplexed with alternate functions for the peripheral features on the device. How each alternate function interferes
with the port pin is described in “Alternate Port Functions” on page 57. Refer to the individual module sections
for a full description of the alternate functions.
Note that enabling the alternate function of some of the port pins does not affect the use of the other pins in the port
as general digital I/O.
10.2 Ports as General Digital I/O
The ports are bi-directional I/O ports with optional internal pull-ups. Figure 10-2 shows a functional description of
one I/O-port pin, here generically called Pxn.
Logic
Rpu
See Figure
"General Digital I/O" for
Details
PxnATtiny25/45/85 [DATASHEET] 54
2586Q–AVR–08/2013
Figure 10-2. General Digital I/O(1)
Note: 1. WRx, WPx, WDx, RRx, RPx, and RDx are common to all pins within the same port. clkI/O, SLEEP, and PUD are
common to all ports.
10.2.1 Configuring the Pin
Each port pin consists of three register bits: DDxn, PORTxn, and PINxn. As shown in “Register Description” on
page 64, the DDxn bits are accessed at the DDRx I/O address, the PORTxn bits at the PORTx I/O address, and
the PINxn bits at the PINx I/O address.
The DDxn bit in the DDRx Register selects the direction of this pin. If DDxn is written logic one, Pxn is configured
as an output pin. If DDxn is written logic zero, Pxn is configured as an input pin.
If PORTxn is written logic one when the pin is configured as an input pin, the pull-up resistor is activated. To switch
the pull-up resistor off, PORTxn has to be written logic zero or the pin has to be configured as an output pin. The
port pins are tri-stated when reset condition becomes active, even if no clocks are running.
If PORTxn is written logic one when the pin is configured as an output pin, the port pin is driven high (one). If
PORTxn is written logic zero when the pin is configured as an output pin, the port pin is driven low (zero).
10.2.2 Toggling the Pin
Writing a logic one to PINxn toggles the value of PORTxn, independent on the value of DDRxn. Note that the SBI
instruction can be used to toggle one single bit in a port.
10.2.3 Switching Between Input and Output
When switching between tri-state ({DDxn, PORTxn} = 0b00) and output high ({DDxn, PORTxn} = 0b11), an intermediate
state with either pull-up enabled {DDxn, PORTxn} = 0b01) or output low ({DDxn, PORTxn} = 0b10) must
occur. Normally, the pull-up enabled state is fully acceptable, as a high-impedant environment will not notice the
clk
RPx
RRx
RDx
WDx
PUD
SYNCHRONIZER
WDx: WRITE DDRx
WRx: WRITE PORTx
RRx: READ PORTx REGISTER
RPx: READ PORTx PIN
PUD: PULLUP DISABLE
clkI/O: I/O CLOCK
RDx: READ DDRx
D
L
Q
Q
RESET
RESET
Q
D Q
Q
Q D
CLR
PORTxn
Q
Q D
CLR
DDxn
PINxn
DATA BUS
SLEEP
SLEEP: SLEEP CONTROL
Pxn
I/O
WPx
0
1
WRx
WPx: WRITE PINx REGISTERATtiny25/45/85 [DATASHEET] 55
2586Q–AVR–08/2013
difference between a strong high driver and a pull-up. If this is not the case, the PUD bit in the MCUCR Register
can be set to disable all pull-ups in all ports.
Switching between input with pull-up and output low generates the same problem. The user must use either the tristate
({DDxn, PORTxn} = 0b00) or the output high state ({DDxn, PORTxn} = 0b10) as an intermediate step.
Table 10-1 summarizes the control signals for the pin value.
10.2.4 Reading the Pin Value
Independent of the setting of Data Direction bit DDxn, the port pin can be read through the PINxn Register bit. As
shown in Figure 10-2, the PINxn Register bit and the preceding latch constitute a synchronizer. This is needed to
avoid metastability if the physical pin changes value near the edge of the internal clock, but it also introduces a
delay. Figure 10-3 shows a timing diagram of the synchronization when reading an externally applied pin value.
The maximum and minimum propagation delays are denoted tpd,max and tpd,min respectively.
Figure 10-3. Synchronization when Reading an Externally Applied Pin value
Consider the clock period starting shortly after the first falling edge of the system clock. The latch is closed when
the clock is low, and goes transparent when the clock is high, as indicated by the shaded region of the “SYNC
LATCH” signal. The signal value is latched when the system clock goes low. It is clocked into the PINxn Register at
the succeeding positive clock edge. As indicated by the two arrows tpd,max and tpd,min, a single signal transition
on the pin will be delayed between ½ and 1½ system clock period depending upon the time of assertion.
When reading back a software assigned pin value, a nop instruction must be inserted as indicated in Figure 10-4.
The out instruction sets the “SYNC LATCH” signal at the positive edge of the clock. In this case, the delay tpd
through the synchronizer is one system clock period.
Table 10-1. Port Pin Configurations
DDxn PORTxn
PUD
(in MCUCR) I/O Pull-up Comment
0 0 X Input No Tri-state (Hi-Z)
0 1 0 Input Yes Pxn will source current if ext. pulled low.
0 1 1 Input No Tri-state (Hi-Z)
1 0 X Output No Output Low (Sink)
1 1 X Output No Output High (Source)
XXX in r17, PINx
0x00 0xFF
INSTRUCTIONS
SYNC LATCH
PINxn
r17
XXX
SYSTEM CLK
tpd, max
tpd, minATtiny25/45/85 [DATASHEET] 56
2586Q–AVR–08/2013
Figure 10-4. Synchronization when Reading a Software Assigned Pin Value
The following code example shows how to set port B pins 0 and 1 high, 2 and 3 low, and define the port pins from
4 to 5 as input with a pull-up assigned to port pin 4. The resulting pin values are read back again, but as previously
discussed, a nop instruction is included to be able to read back the value recently assigned to some of the pins.
Note: 1. For the assembly program, two temporary registers are used to minimize the time from pull-ups are set on pins 0, 1
and 4, until the direction bits are correctly set, defining bit 2 and 3 as low and redefining bits 0 and 1 as strong high
drivers.
Assembly Code Example(1)
...
; Define pull-ups and set outputs high
; Define directions for port pins
ldi r16,(1< CS0[2:0] > 1). The number of system clock cycles from when the timer is
enabled to the first count occurs can be from 1 to N+1 system clock cycles, where N equals the prescaler divisor
(8, 64, 256, or 1024).
It is possible to use the Prescaler Reset for synchronizing the Timer/Counter to program execution.
Table 11-1. Definitions
Constant Description
BOTTOM The counter reaches BOTTOM when it becomes 0x00
MAX The counter reaches its MAXimum when it becomes 0xFF (decimal 255)
TOP
The counter reaches the TOP when it becomes equal to the highest value in the count
sequence. The TOP value can be assigned to be the fixed value 0xFF (MAX) or the
value stored in the OCR0A Register. The assignment depends on the mode of operationATtiny25/45/85 [DATASHEET] 67
2586Q–AVR–08/2013
11.3.3 External Clock Source
An external clock source applied to the T0 pin can be used as timer/counter clock (clkT0). The T0 pin is sampled
once every system clock cycle by the pin synchronization logic. The synchronized (sampled) signal is then passed
through the edge detector. Figure 11-2 shows a functional equivalent block diagram of the T0 synchronization and
edge detector logic. The registers are clocked at the positive edge of the internal system clock (clkI/O). The latch is
transparent in the high period of the internal system clock.
The edge detector generates one clkT0 pulse for each positive (CS0[2:0] = 7) or negative (CS0[2:0] = 6) edge it
detects.
Figure 11-2. T0 Pin Sampling
The synchronization and edge detector logic introduces a delay of 2.5 to 3.5 system clock cycles from an edge has
been applied to the T0 pin to the counter is updated.
Enabling and disabling of the clock input must be done when T0 has been stable for at least one system clock
cycle, otherwise it is a risk that a false timer/counter clock pulse is generated.
Each half period of the external clock applied must be longer than one system clock cycle to ensure correct sampling.
The external clock must be guaranteed to have less than half the system clock frequency (fExtClk < fclk_I/O/2)
given a 50/50% duty cycle. Since the edge detector uses sampling, the maximum frequency of an external clock it
can detect is half the sampling frequency (following the Nyquist sampling theorem). However, due to variation of
the system clock frequency and duty cycle caused by oscillator source (crystal, resonator, and capacitors) tolerances,
it is recommended that maximum frequency of an external clock source is less than fclk_I/O/2.5.
An external clock source can not be prescaled.
Tn_sync
(To Clock
Select Logic)
Synchronization Edge Detector
D Q D Q
LE
Tn D Q
clkI/OATtiny25/45/85 [DATASHEET] 68
2586Q–AVR–08/2013
Figure 11-3. Timer/Counter0 Prescaler
The synchronization logic on the input pins (T0) in Figure 11-3 is shown in Figure 11-2 on page 67.
11.4 Counter Unit
The main part of the 8-bit Timer/Counter is the programmable bi-directional counter unit. Figure 11-4 shows a
block diagram of the counter and its surroundings.
Figure 11-4. Counter Unit Block Diagram
Signal description (internal signals):
count Increment or decrement TCNT0 by 1.
direction Select between increment and decrement.
clear Clear TCNT0 (set all bits to zero).
clkTn Timer/Counter clock, referred to as clkT0 in the following.
top Signalize that TCNT0 has reached maximum value.
bottom Signalize that TCNT0 has reached minimum value (zero).
Depending of the mode of operation used, the counter is cleared, incremented, or decremented at each timer clock
(clkT0). clkT0 can be generated from an external or internal clock source, selected by the Clock Select bits
(CS0[2:0]). When no clock source is selected (CS0[2:0] = 0) the timer is stopped. However, the TCNT0 value can
PSR10
Clear
clkT0
T0
clkI/O
Synchronization
DATA BUS
TCNTn Control Logic
count
TOVn
(Int.Req.)
Clock Select
top
Tn Edge
Detector
( From Prescaler )
clkTn
bottom
direction
clearATtiny25/45/85 [DATASHEET] 69
2586Q–AVR–08/2013
be accessed by the CPU, regardless of whether clkT0 is present or not. A CPU write overrides (has priority over) all
counter clear or count operations.
The counting sequence is determined by the setting of the WGM01 and WGM00 bits located in the Timer/Counter
Control Register (TCCR0A) and the WGM02 bit located in the Timer/Counter Control Register B (TCCR0B). There
are close connections between how the counter behaves (counts) and how waveforms are generated on the Output
Compare output OC0A. For more details about advanced counting sequences and waveform generation, see
“Modes of Operation” on page 71.
The Timer/Counter Overflow Flag (TOV0) is set according to the mode of operation selected by the WGM0[1:0]
bits. TOV0 can be used for generating a CPU interrupt.
11.5 Output Compare Unit
The 8-bit comparator continuously compares TCNT0 with the Output Compare Registers (OCR0A and OCR0B).
Whenever TCNT0 equals OCR0A or OCR0B, the comparator signals a match. A match will set the Output Compare
Flag (OCF0A or OCF0B) at the next timer clock cycle. If the corresponding interrupt is enabled, the Output
Compare Flag generates an Output Compare interrupt. The Output Compare Flag is automatically cleared when
the interrupt is executed. Alternatively, the flag can be cleared by software by writing a logical one to its I/O bit location.
The Waveform Generator uses the match signal to generate an output according to operating mode set by the
WGM0[2:0] bits and Compare Output mode (COM0x[1:0]) bits. The max and bottom signals are used by the Waveform
Generator for handling the special cases of the extreme values in some modes of operation (See “Modes of
Operation” on page 71.).
Figure 11-5 shows a block diagram of the Output Compare unit.
Figure 11-5. Output Compare Unit, Block Diagram
The OCR0x Registers are double buffered when using any of the Pulse Width Modulation (PWM) modes. For the
normal and Clear Timer on Compare (CTC) modes of operation, the double buffering is disabled. The double buffering
synchronizes the update of the OCR0x Compare Registers to either top or bottom of the counting sequence.
The synchronization prevents the occurrence of odd-length, non-symmetrical PWM pulses, thereby making the
output glitch-free.
OCFnx (Int.Req.)
= (8-bit Comparator )
OCRnx
OCnx
DATA BUS
TCNTn
WGMn[1:0]
Waveform Generator
top
FOCn
COMnX[1:0]
bottomATtiny25/45/85 [DATASHEET] 70
2586Q–AVR–08/2013
The OCR0x Register access may seem complex, but this is not case. When the double buffering is enabled, the
CPU has access to the OCR0x Buffer Register, and if double buffering is disabled the CPU will access the OCR0x
directly.
11.5.1 Force Output Compare
In non-PWM waveform generation modes, the match output of the comparator can be forced by writing a one to
the Force Output Compare (FOC0x) bit. Forcing Compare Match will not set the OCF0x Flag or reload/clear the
timer, but the OC0x pin will be updated as if a real Compare Match had occurred (the COM0x[1:0] bits settings
define whether the OC0x pin is set, cleared or toggled).
11.5.2 Compare Match Blocking by TCNT0 Write
All CPU write operations to the TCNT0 Register will block any Compare Match that occur in the next timer clock
cycle, even when the timer is stopped. This feature allows OCR0x to be initialized to the same value as TCNT0
without triggering an interrupt when the Timer/Counter clock is enabled.
11.5.3 Using the Output Compare Unit
Since writing TCNT0 in any mode of operation will block all Compare Matches for one timer clock cycle, there are
risks involved when changing TCNT0 when using the Output Compare Unit, independently of whether the
Timer/Counter is running or not. If the value written to TCNT0 equals the OCR0x value, the Compare Match will be
missed, resulting in incorrect waveform generation. Similarly, do not write the TCNT0 value equal to BOTTOM
when the counter is down-counting.
The setup of the OC0x should be performed before setting the Data Direction Register for the port pin to output.
The easiest way of setting the OC0x value is to use the Force Output Compare (FOC0x) strobe bits in Normal
mode. The OC0x Registers keep their values even when changing between Waveform Generation modes.
Be aware that the COM0x[1:0] bits are not double buffered together with the compare value. Changing the
COM0x[1:0] bits will take effect immediately.
11.6 Compare Match Output Unit
The Compare Output mode (COM0x[1:0]) bits have two functions. The Waveform Generator uses the COM0x[1:0]
bits for defining the Output Compare (OC0x) state at the next Compare Match. Also, the COM0x[1:0] bits control
the OC0x pin output source. Figure 11-6 shows a simplified schematic of the logic affected by the COM0x[1:0] bit
setting. The I/O Registers, I/O bits, and I/O pins in the figure are shown in bold. Only the parts of the general I/O
Port Control Registers (DDR and PORT) that are affected by the COM0x[1:0] bits are shown. When referring to the
OC0x state, the reference is for the internal OC0x Register, not the OC0x pin. If a system reset occur, the OC0x
Register is reset to “0”.ATtiny25/45/85 [DATASHEET] 71
2586Q–AVR–08/2013
Figure 11-6. Compare Match Output Unit, Schematic
The general I/O port function is overridden by the Output Compare (OC0x) from the Waveform Generator if either
of the COM0x[1:0] bits are set. However, the OC0x pin direction (input or output) is still controlled by the Data
Direction Register (DDR) for the port pin. The Data Direction Register bit for the OC0x pin (DDR_OC0x) must be
set as output before the OC0x value is visible on the pin. The port override function is independent of the Waveform
Generation mode.
The design of the Output Compare pin logic allows initialization of the OC0x state before the output is enabled.
Note that some COM0x[1:0] bit settings are reserved for certain modes of operation. See “Register Description” on
page 77.
11.6.1 Compare Output Mode and Waveform Generation
The Waveform Generator uses the COM0x[1:0] bits differently in Normal, CTC, and PWM modes. For all modes,
setting the COM0x[1:0] = 0 tells the Waveform Generator that no action on the OC0x Register is to be performed
on the next Compare Match. For compare output actions in the non-PWM modes refer to Table 11-2 on page 78.
For fast PWM mode, refer to Table 11-3 on page 78, and for phase correct PWM refer to Table 11-4 on page 78.
A change of the COM0x[1:0] bits state will have effect at the first Compare Match after the bits are written. For nonPWM
modes, the action can be forced to have immediate effect by using the FOC0x strobe bits.
11.7 Modes of Operation
The mode of operation, i.e., the behavior of the Timer/Counter and the Output Compare pins, is defined by the
combination of the Waveform Generation mode (WGM0[2:0]) and Compare Output mode (COM0x[1:0]) bits. The
Compare Output mode bits do not affect the counting sequence, while the Waveform Generation mode bits do.
The COM0x[1:0] bits control whether the PWM output generated should be inverted or not (inverted or noninverted
PWM). For non-PWM modes the COM0x[1:0] bits control whether the output should be set, cleared, or
toggled at a Compare Match (See “Compare Match Output Unit” on page 70.).
PORT
DDR
D Q
D Q
OCn
OCnx Pin
D Q Waveform
Generator
COMnx1
COMnx0
0
1
DATA BU
S
FOCn
clkI/OATtiny25/45/85 [DATASHEET] 72
2586Q–AVR–08/2013
For detailed timing information refer to Figure 11-10, Figure 11-11, Figure 11-12 and Figure 11-13 in “Timer/Counter
Timing Diagrams” on page 76.
11.7.1 Normal Mode
The simplest mode of operation is the Normal mode (WGM0[2:0] = 0). In this mode the counting direction is always
up (incrementing), and no counter clear is performed. The counter simply overruns when it passes its maximum 8-
bit value (TOP = 0xFF) and then restarts from the bottom (0x00). In normal operation the Timer/Counter Overflow
Flag (TOV0) will be set in the same timer clock cycle as the TCNT0 becomes zero. The TOV0 Flag in this case
behaves like a ninth bit, except that it is only set, not cleared. However, combined with the timer overflow interrupt
that automatically clears the TOV0 Flag, the timer resolution can be increased by software. There are no special
cases to consider in the Normal mode, a new counter value can be written anytime.
The Output Compare Unit can be used to generate interrupts at some given time. Using the Output Compare to
generate waveforms in Normal mode is not recommended, since this will occupy too much of the CPU time.
11.7.2 Clear Timer on Compare Match (CTC) Mode
In Clear Timer on Compare or CTC mode (WGM0[2:0] = 2), the OCR0A Register is used to manipulate the counter
resolution. In CTC mode the counter is cleared to zero when the counter value (TCNT0) matches the OCR0A. The
OCR0A defines the top value for the counter, hence also its resolution. This mode allows greater control of the
Compare Match output frequency. It also simplifies the operation of counting external events.
The timing diagram for the CTC mode is shown in Figure 11-7. The counter value (TCNT0) increases until a Compare
Match occurs between TCNT0 and OCR0A, and then counter (TCNT0) is cleared.
Figure 11-7. CTC Mode, Timing Diagram
An interrupt can be generated each time the counter value reaches the TOP value by using the OCF0A Flag. If the
interrupt is enabled, the interrupt handler routine can be used for updating the TOP value. However, changing TOP
to a value close to BOTTOM when the counter is running with none or a low prescaler value must be done with
care since the CTC mode does not have the double buffering feature. If the new value written to OCR0A is lower
than the current value of TCNT0, the counter will miss the Compare Match. The counter will then have to count to
its maximum value (0xFF) and wrap around starting at 0x00 before the Compare Match can occur.
For generating a waveform output in CTC mode, the OC0A output can be set to toggle its logical level on each
Compare Match by setting the Compare Output mode bits to toggle mode (COM0A[1:0] = 1). The OC0A value will
not be visible on the port pin unless the data direction for the pin is set to output. The waveform generated will have
a maximum frequency of fOC0 = fclk_I/O/2 when OCR0A is set to zero (0x00). The waveform frequency is defined by
the following equation:
TCNTn
OCn
(Toggle)
OCnx Interrupt Flag Set
Period 1 2 3 4
(COMnx[1:0] = 1)
f
OCnx
f
clk_I/O
2 N 1 OCRnx + = --------------------------------------------------ATtiny25/45/85 [DATASHEET] 73
2586Q–AVR–08/2013
The N variable represents the prescale factor (1, 8, 64, 256, or 1024).
As for the Normal mode of operation, the TOV0 Flag is set in the same timer clock cycle that the counter counts
from MAX to 0x00.
11.7.3 Fast PWM Mode
The fast Pulse Width Modulation or fast PWM mode (WGM0[2:0] = 3 or 7) provides a high frequency PWM waveform
generation option. The fast PWM differs from the other PWM option by its single-slope operation. The counter
counts from BOTTOM to TOP then restarts from BOTTOM. TOP is defined as 0xFF when WGM0[2:0] = 3, and
OCR0A when WGM0[2:0] = 7.
In non-inverting Compare Output mode, the Output Compare (OC0x) is cleared on the Compare Match between
TCNT0 and OCR0x, and set at BOTTOM. In inverting Compare Output mode, the output is set on Compare Match
and cleared at BOTTOM.
Due to the single-slope operation, the operating frequency of the fast PWM mode can be twice as high as the
phase correct PWM mode that use dual-slope operation. This high frequency makes the fast PWM mode well
suited for power regulation, rectification, and DAC applications. High frequency allows physically small sized external
components (coils, capacitors), and therefore reduces total system cost.
In fast PWM mode, the counter is incremented until the counter value matches the TOP value. The counter is then
cleared at the following timer clock cycle. The timing diagram for the fast PWM mode is shown in Figure 11-8. The
TCNT0 value is in the timing diagram shown as a histogram for illustrating the single-slope operation. The diagram
includes non-inverted and inverted PWM outputs. The small horizontal line marks on the TCNT0 slopes represent
Compare Matches between OCR0x and TCNT0.
Figure 11-8. Fast PWM Mode, Timing Diagram
The Timer/Counter Overflow Flag (TOV0) is set each time the counter reaches TOP. If the interrupt is enabled, the
interrupt handler routine can be used for updating the compare value.
In fast PWM mode, the compare unit allows generation of PWM waveforms on the OC0x pins. Setting the
COM0x[1:0] bits to two will produce a non-inverted PWM and an inverted PWM output can be generated by setting
the COM0x[1:0] to three: Setting the COM0A[1:0] bits to one allowes the AC0A pin to toggle on Compare Matches
if the WGM02 bit is set. This option is not available for the OC0B pin (See Table 11-3 on page 78). The actual
OC0x value will only be visible on the port pin if the data direction for the port pin is set as output. The PWM waveTCNTn
OCRnx Update and
TOVn Interrupt Flag Set
Period 1 2 3
OCn
OCn
(COMnx[1:0] = 2)
(COMnx[1:0] = 3)
OCRnx Interrupt Flag Set
4 5 6 7ATtiny25/45/85 [DATASHEET] 74
2586Q–AVR–08/2013
form is generated by setting (or clearing) the OC0x Register at the Compare Match between OCR0x and TCNT0,
and clearing (or setting) the OC0x Register at the timer clock cycle the counter is cleared (changes from TOP to
BOTTOM).
The PWM frequency for the output can be calculated by the following equation:
The N variable represents the prescale factor (1, 8, 64, 256, or 1024).
The extreme values for the OCR0A Register represents special cases when generating a PWM waveform output in
the fast PWM mode. If the OCR0A is set equal to BOTTOM, the output will be a narrow spike for each MAX+1
timer clock cycle. Setting the OCR0A equal to MAX will result in a constantly high or low output (depending on the
polarity of the output set by the COM0A[1:0] bits.)
A frequency (with 50% duty cycle) waveform output in fast PWM mode can be achieved by setting OC0x to toggle
its logical level on each Compare Match (COM0x[1:0] = 1). The waveform generated will have a maximum frequency
of fOC0 = fclk_I/O/2 when OCR0A is set to zero. This feature is similar to the OC0A toggle in CTC mode,
except the double buffer feature of the Output Compare unit is enabled in the fast PWM mode.
11.7.4 Phase Correct PWM Mode
The phase correct PWM mode (WGM0[2:0] = 1 or 5) provides a high resolution phase correct PWM waveform generation
option. The phase correct PWM mode is based on a dual-slope operation. The counter counts repeatedly
from BOTTOM to TOP and then from TOP to BOTTOM. TOP is defined as 0xFF when WGM0[2:0] = 1, and
OCR0A when WGM0[2:0] = 5. In non-inverting Compare Output mode, the Output Compare (OC0x) is cleared on
the Compare Match between TCNT0 and OCR0x while upcounting, and set on the Compare Match while downcounting.
In inverting Output Compare mode, the operation is inverted. The dual-slope operation has lower maximum
operation frequency than single slope operation. However, due to the symmetric feature of the dual-slope
PWM modes, these modes are preferred for motor control applications.
In phase correct PWM mode the counter is incremented until the counter value matches TOP. When the counter
reaches TOP, it changes the count direction. The TCNT0 value will be equal to TOP for one timer clock cycle. The
timing diagram for the phase correct PWM mode is shown on Figure 11-9. The TCNT0 value is in the timing diagram
shown as a histogram for illustrating the dual-slope operation. The diagram includes non-inverted and
inverted PWM outputs. The small horizontal line marks on the TCNT0 slopes represent Compare Matches
between OCR0x and TCNT0.
f
OCnxPWM
f
clk_I/O
N 256 = ------------------ATtiny25/45/85 [DATASHEET] 75
2586Q–AVR–08/2013
Figure 11-9. Phase Correct PWM Mode, Timing Diagram
The Timer/Counter Overflow Flag (TOV0) is set each time the counter reaches BOTTOM. The Interrupt Flag can
be used to generate an interrupt each time the counter reaches the BOTTOM value.
In phase correct PWM mode, the compare unit allows generation of PWM waveforms on the OC0x pins. Setting
the COM0x[1:0] bits to two will produce a non-inverted PWM. An inverted PWM output can be generated by setting
the COM0x[1:0] to three: Setting the COM0A0 bits to one allows the OC0A pin to toggle on Compare Matches if
the WGM02 bit is set. This option is not available for the OC0B pin (See Table 11-4 on page 78). The actual OC0x
value will only be visible on the port pin if the data direction for the port pin is set as output. The PWM waveform is
generated by clearing (or setting) the OC0x Register at the Compare Match between OCR0x and TCNT0 when the
counter increments, and setting (or clearing) the OC0x Register at Compare Match between OCR0x and TCNT0
when the counter decrements. The PWM frequency for the output when using phase correct PWM can be calculated
by the following equation:
The N variable represents the prescale factor (1, 8, 64, 256, or 1024).
The extreme values for the OCR0A Register represent special cases when generating a PWM waveform output in
the phase correct PWM mode. If the OCR0A is set equal to BOTTOM, the output will be continuously low and if set
equal to MAX the output will be continuously high for non-inverted PWM mode. For inverted PWM the output will
have the opposite logic values.
At the very start of period 2 in Figure 11-9 OCn has a transition from high to low even though there is no Compare
Match. The point of this transition is to guaratee symmetry around BOTTOM. There are two cases that give a transition
without Compare Match, as follows:
• OCR0A changes its value from MAX, like in Figure 11-9. When the OCR0A value is MAX the OCn pin value is
the same as the result of a down-counting Compare Match. To ensure symmetry around BOTTOM the OCn
value at MAX must correspond to the result of an up-counting Compare Match.
TOVn Interrupt Flag Set
OCnx Interrupt Flag Set
1 2 3
TCNTn
Period
OCn
OCn
(COMnx[1:0] = 2)
(COMnx[1:0] = 3)
OCRnx Update
f
OCnxPCPWM
f
clk_I/O
N 510 = ------------------ATtiny25/45/85 [DATASHEET] 76
2586Q–AVR–08/2013
• The timer starts counting from a value higher than the one in OCR0A, and for that reason misses the Compare
Match and hence the OCn change that would have happened on the way up.
11.8 Timer/Counter Timing Diagrams
The Timer/Counter is a synchronous design and the timer clock (clkT0) is therefore shown as a clock enable signal
in the following figures. The figures include information on when Interrupt Flags are set. Figure 11-10 contains timing
data for basic Timer/Counter operation. The figure shows the count sequence close to the MAX value in all
modes other than phase correct PWM mode.
Figure 11-10. Timer/Counter Timing Diagram, no Prescaling
Figure 11-11 shows the same timing data, but with the prescaler enabled.
Figure 11-11. Timer/Counter Timing Diagram, with Prescaler (fclk_I/O/8)
Figure 11-12 shows the setting of OCF0B in all modes and OCF0A in all modes except CTC mode and PWM
mode, where OCR0A is TOP.
Figure 11-12. Timer/Counter Timing Diagram, Setting of OCF0x, with Prescaler (fclk_I/O/8)
clkTn
(clkI/O/1)
TOVn
clkI/O
TCNTn MAX - 1 MAX BOTTOM BOTTOM + 1
TOVn
TCNTn MAX - 1 MAX BOTTOM BOTTOM + 1
clkI/O
clkTn
(clkI/O/8)
OCFnx
OCRnx
TCNTn
OCRnx Value
OCRnx - 1 OCRnx OCRnx + 1 OCRnx + 2
clkI/O
clkTn
(clkI/O/8)ATtiny25/45/85 [DATASHEET] 77
2586Q–AVR–08/2013
Figure 11-13 shows the setting of OCF0A and the clearing of TCNT0 in CTC mode and fast PWM mode where
OCR0A is TOP.
Figure 11-13. Timer/Counter Timing Diagram, Clear Timer on Compare Match mode, with Prescaler (fclk_I/O/8)
11.9 Register Description
11.9.1 GTCCR – General Timer/Counter Control Register
• Bit 7 – TSM: Timer/Counter Synchronization Mode
Writing the TSM bit to one activates the Timer/Counter Synchronization Mode. In this mode, the value written to
PSR0 is kept, hence keeping the Prescaler Reset signal asserted. This ensures that the timer/counter is halted and
can be configured without the risk of advancing during configuration. When the TSM bit is written to zero, the PSR0
bit is cleared by hardware, and the timer/counter start counting.
• Bit 0 – PSR0: Prescaler Reset Timer/Counter0
When this bit is one, the Timer/Counter0 prescaler will be Reset. This bit is normally cleared immediately by hardware,
except if the TSM bit is set.
11.9.2 TCCR0A – Timer/Counter Control Register A
• Bits 7:6 – COM0A[1:0]: Compare Match Output A Mode
• Bits 5:4 – COM0B[1:0]: Compare Match Output B Mode
The COM0A[1:0] and COM0B[1:0] bits control the behaviour of Output Compare pins OC0A and OC0B, respectively.
If any of the COM0A[1:0] bits are set, the OC0A output overrides the normal port functionality of the I/O pin it
is connected to. Similarly, if any of the COM0B[1:0] bits are set, the OC0B output overrides the normal port functionality
of the I/O pin it is connected to. However, note that the Data Direction Register (DDR) bit corresponding to
the OC0A and OC0B pins must be set in order to enable the output driver.
OCFnx
OCRnx
TCNTn
(CTC)
TOP
TOP - 1 TOP BOTTOM BOTTOM + 1
clkI/O
clkTn
(clkI/O/8)
Bit 7 6 5 4 3 2 1 0
0x2C TSM PWM1B COM1B1 COM1B0 FOC1B FOC1A PSR1 PSR0 GTCCR
Read/Write R/W R R R R R R R/W
Initial Value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x2A COM0A1 COM0A0 COM0B1 COM0B0 – – WGM01 WGM00 TCCR0A
Read/Write R/W R/W R/W R/W R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 78
2586Q–AVR–08/2013
When OC0A/OC0B is connected to the I/O pin, the function of the COM0A[1:0]/COM0B[1:0] bits depend on the
WGM0[2:0] bit setting. Table 11-2 shows the COM0x[1:0] bit functionality when the WGM0[2:0] bits are set to a
normal or CTC mode (non-PWM).
Table 11-3 shows the COM0x[1:0] bit functionality when the WGM0[2:0] bits are set to fast PWM mode.
Note: 1. A special case occurs when OCR0A or OCR0B equals TOP and COM0A1/COM0B1 is set. In this case, the compare
match is ignored, but the set or clear is done at BOTTOM. See “Fast PWM Mode” on page 73 for more details.
Table 11-4 shows the COM0x[1:0] bit functionality when the WGM0[2:0] bits are set to phase correct PWM mode.
Note: 1. A special case occurs when OCR0A or OCR0B equals TOP and COM0A1/COM0B1 is set. In this case, the Compare
Match is ignored, but the set or clear is done at TOP. See “Phase Correct PWM Mode” on page 74 for more
details.
• Bits 3:2 – Res: Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and will always read as zero.
Table 11-2. Compare Output Mode, non-PWM Mode
COM0A1
COM0B1
COM0A0
COM0B0 Description
0 0 Normal port operation, OC0A/OC0B disconnected.
0 1 Toggle OC0A/OC0B on Compare Match
1 0 Clear OC0A/OC0B on Compare Match
1 1 Set OC0A/OC0B on Compare Match
Table 11-3. Compare Output Mode, Fast PWM Mode(1)
COM0A1
COM0B1
COM0A0
COM0B0 Description
0 0 Normal port operation, OC0A/OC0B disconnected.
0 1 Reserved
1 0 Clear OC0A/OC0B on Compare Match, set OC0A/OC0B at BOTTOM
(non-inverting mode)
1 1 Set OC0A/OC0B on Compare Match, clear OC0A/OC0B at BOTTOM
(inverting mode)
Table 11-4. Compare Output Mode, Phase Correct PWM Mode(1)
COM0A1
COM0B1
COM0A0
COM0B0 Description
0 0 Normal port operation, OC0A/OC0B disconnected.
0 1 Reserved
1 0 Clear OC0A/OC0B on Compare Match when up-counting.
Set OC0A/OC0B on Compare Match when down-counting.
1 1 Set OC0A/OC0B on Compare Match when up-counting.
Clear OC0A/OC0B on Compare Match when down-counting.ATtiny25/45/85 [DATASHEET] 79
2586Q–AVR–08/2013
• Bits 1:0 – WGM0[1:0]: Waveform Generation Mode
Combined with the WGM02 bit found in the TCCR0B Register, these bits control the counting sequence of the
counter, the source for maximum (TOP) counter value, and what type of waveform generation to be used, see
Table 11-5. Modes of operation supported by the Timer/Counter unit are: Normal mode (counter), Clear Timer on
Compare Match (CTC) mode, and two types of Pulse Width Modulation (PWM) modes (see “Modes of Operation”
on page 71).
Notes: 1. MAX = 0xFF
2. BOTTOM = 0x00
11.9.3 TCCR0B – Timer/Counter Control Register B
• Bit 7 – FOC0A: Force Output Compare A
The FOC0A bit is only active when the WGM bits specify a non-PWM mode.
However, for ensuring compatibility with future devices, this bit must be set to zero when TCCR0B is written when
operating in PWM mode. When writing a logical one to the FOC0A bit, an immediate Compare Match is forced on
the Waveform Generation unit. The OC0A output is changed according to its COM0A[1:0] bits setting. Note that
the FOC0A bit is implemented as a strobe. Therefore it is the value present in the COM0A[1:0] bits that determines
the effect of the forced compare.
A FOC0A strobe will not generate any interrupt, nor will it clear the timer in CTC mode using OCR0A as TOP.
The FOC0A bit is always read as zero.
• Bit 6 – FOC0B: Force Output Compare B
The FOC0B bit is only active when the WGM bits specify a non-PWM mode.
However, for ensuring compatibility with future devices, this bit must be set to zero when TCCR0B is written when
operating in PWM mode. When writing a logical one to the FOC0B bit, an immediate Compare Match is forced on
the Waveform Generation unit. The OC0B output is changed according to its COM0B[1:0] bits setting. Note that
the FOC0B bit is implemented as a strobe. Therefore it is the value present in the COM0B[1:0] bits that determines
the effect of the forced compare.
A FOC0B strobe will not generate any interrupt, nor will it clear the timer in CTC mode using OCR0B as TOP.
Table 11-5. Waveform Generation Mode Bit Description
Mode
WGM
02
WGM
01
WGM
00
Timer/Counter Mode
of Operation TOP
Update of
OCRx at
TOV Flag
Set on
0 0 0 0 Normal 0xFF Immediate MAX(1)
1 0 0 1 PWM, Phase Correct 0xFF TOP BOTTOM(2)
2 0 1 0 CTC OCRA Immediate MAX(1)
3 0 1 1 Fast PWM 0xFF BOTTOM(2) MAX(1)
4 1 0 0 Reserved – – –
5 1 0 1 PWM, Phase Correct OCRA TOP BOTTOM(2)
6 1 1 0 Reserved – – –
7 1 1 1 Fast PWM OCRA BOTTOM(2) TOP
Bit 7 6 5 4 3 2 1 0
0x33 FOC0A FOC0B – – WGM02 CS02 CS01 CS00 TCCR0B
Read/Write W W R R R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 80
2586Q–AVR–08/2013
The FOC0B bit is always read as zero.
• Bits 5:4 – Res: Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and will always read as zero.
• Bit 3 – WGM02: Waveform Generation Mode
See the description in the “TCCR0A – Timer/Counter Control Register A” on page 77.
• Bits 2:0 – CS0[2:0]: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter.
If external pin modes are used for the Timer/Counter0, transitions on the T0 pin will clock the counter even if the
pin is configured as an output. This feature allows software control of the counting.
11.9.4 TCNT0 – Timer/Counter Register
The Timer/Counter Register gives direct access, both for read and write operations, to the Timer/Counter unit 8-bit
counter. Writing to the TCNT0 Register blocks (removes) the Compare Match on the following timer clock. Modifying
the counter (TCNT0) while the counter is running, introduces a risk of missing a Compare Match between
TCNT0 and the OCR0x Registers.
11.9.5 OCR0A – Output Compare Register A
The Output Compare Register A contains an 8-bit value that is continuously compared with the counter value
(TCNT0). A match can be used to generate an Output Compare interrupt, or to generate a waveform output on the
OC0A pin.
Table 11-6. Clock Select Bit Description
CS02 CS01 CS00 Description
0 0 0 No clock source (Timer/Counter stopped)
0 0 1 clkI/O/(No prescaling)
0 1 0 clkI/O/8 (From prescaler)
0 1 1 clkI/O/64 (From prescaler)
1 0 0 clkI/O/256 (From prescaler)
1 0 1 clkI/O/1024 (From prescaler)
1 1 0 External clock source on T0 pin. Clock on falling edge.
1 1 1 External clock source on T0 pin. Clock on rising edge.
Bit 7 6 5 4 3 2 1 0
0x32 TCNT0[7:0] TCNT0
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x29 OCR0A[7:0] OCR0A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 81
2586Q–AVR–08/2013
11.9.6 OCR0B – Output Compare Register B
The Output Compare Register B contains an 8-bit value that is continuously compared with the counter value
(TCNT0). A match can be used to generate an Output Compare interrupt, or to generate a waveform output on the
OC0B pin.
11.9.7 TIMSK – Timer/Counter Interrupt Mask Register
• Bits 7, 0 – Res: Reserved Bits
These bits are reserved bits and will always read as zero.
• Bit 4 – OCIE0A: Timer/Counter0 Output Compare Match A Interrupt Enable
When the OCIE0A bit is written to one, and the I-bit in the Status Register is set, the Timer/Counter0 Compare
Match A interrupt is enabled. The corresponding interrupt is executed if a Compare Match in Timer/Counter0
occurs, i.e., when the OCF0A bit is set in the Timer/Counter 0 Interrupt Flag Register – TIFR0.
• Bit 3 – OCIE0B: Timer/Counter Output Compare Match B Interrupt Enable
When the OCIE0B bit is written to one, and the I-bit in the Status Register is set, the Timer/Counter Compare
Match B interrupt is enabled. The corresponding interrupt is executed if a Compare Match in Timer/Counter occurs,
i.e., when the OCF0B bit is set in the Timer/Counter Interrupt Flag Register – TIFR0.
• Bit 1 – TOIE0: Timer/Counter0 Overflow Interrupt Enable
When the TOIE0 bit is written to one, and the I-bit in the Status Register is set, the Timer/Counter0 Overflow interrupt
is enabled. The corresponding interrupt is executed if an overflow in Timer/Counter0 occurs, i.e., when the
TOV0 bit is set in the Timer/Counter 0 Interrupt Flag Register – TIFR0.
11.9.8 TIFR – Timer/Counter Interrupt Flag Register
• Bits 7, 0 – Res: Reserved Bits
These bits are reserved bits and will always read as zero.
• Bit 4 – OCF0A: Output Compare Flag 0 A
The OCF0A bit is set when a Compare Match occurs between the Timer/Counter0 and the data in OCR0A – Output
Compare Register0. OCF0A is cleared by hardware when executing the corresponding interrupt handling
vector. Alternatively, OCF0A is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE0A
(Timer/Counter0 Compare Match Interrupt Enable), and OCF0A are set, the Timer/Counter0 Compare Match Interrupt
is executed.
Bit 7 6 5 4 3 2 1 0
0x28 OCR0B[7:0] OCR0B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x39 – OCIE1A OCIE1B OCIE0A OCIE0B TOIE1 TOIE0 – TIMSK
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial Value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x38 – OCF1A OCF1B OCF0A OCF0B TOV1 TOV0 – TIFR
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial Value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 82
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• Bit 3 – OCF0B: Output Compare Flag 0 B
The OCF0B bit is set when a Compare Match occurs between the Timer/Counter and the data in OCR0B – Output
Compare Register0 B. OCF0B is cleared by hardware when executing the corresponding interrupt handling vector.
Alternatively, OCF0B is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE0B (Timer/Counter
Compare B Match Interrupt Enable), and OCF0B are set, the Timer/Counter Compare Match Interrupt is executed.
• Bit 1 – TOV0: Timer/Counter0 Overflow Flag
The bit TOV0 is set when an overflow occurs in Timer/Counter0. TOV0 is cleared by hardware when executing the
corresponding interrupt handling vector. Alternatively, TOV0 is cleared by writing a logic one to the flag. When the
SREG I-bit, TOIE0 (Timer/Counter0 Overflow Interrupt Enable), and TOV0 are set, the Timer/Counter0 Overflow
interrupt is executed.
The setting of this flag is dependent of the WGM0[2:0] bit setting. Refer to Table 11-5, “Waveform Generation
Mode Bit Description” on page 79.ATtiny25/45/85 [DATASHEET] 83
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12. 8-bit Timer/Counter1
The Timer/Counter1 is a general purpose 8-bit Timer/Counter module that has a separate prescaling selection
from the separate prescaler.
12.1 Timer/Counter1 Prescaler
Figure 12-1 shows the Timer/Counter1 prescaler that supports two clocking modes, a synchronous clocking mode
and an asynchronous clocking mode. The synchronous clocking mode uses the system clock (CK) as the clock
timebase and asynchronous mode uses the fast peripheral clock (PCK) as the clock time base. The PCKE bit from
the PLLCSR register enables the asynchronous mode when it is set (‘1’).
Figure 12-1. Timer/Counter1 Prescaler
In the asynchronous clocking mode the clock selections are from PCK to PCK/16384 and stop, and in the synchronous
clocking mode the clock selections are from CK to CK/16384 and stop. The clock options are described in
Table 12-5 on page 89 and the Timer/Counter1 Control Register, TCCR1. Setting the PSR1 bit in GTCCR register
resets the prescaler. The PCKE bit in the PLLCSR register enables the asynchronous mode. The frequency of the
fast peripheral clock is 64 MHz (or 32 MHz in Low Speed Mode).
12.2 Counter and Compare Units
The Timer/Counter1 general operation is described in the asynchronous mode and the operation in the synchronous
mode is mentioned only if there are differences between these two modes. Figure 12-2 shows Timer/Counter
1 synchronization register block diagram and synchronization delays in between registers. Note that all clock gating
details are not shown in the figure. The Timer/Counter1 register values go through the internal synchronization
registers, which cause the input synchronization delay, before affecting the counter operation. The registers
TCCR1, GTCCR, OCR1A, OCR1B, and OCR1C can be read back right after writing the register. The read back
values are delayed for the Timer/Counter1 (TCNT1) register and flags (OCF1A, OCF1B, and TOV1), because of
the input and output synchronization.
The Timer/Counter1 features a high resolution and a high accuracy usage with the lower prescaling opportunities.
It can also support two accurate, high speed, 8-bit Pulse Width Modulators using clock speeds up to 64 MHz (or 32
MHz in Low Speed Mode). In this mode, Timer/Counter1 and the output compare registers serve as dual standalone
PWMs with non-overlapping non-inverted and inverted outputs. Refer to page 86 for a detailed description
on this function. Similarly, the high prescaling opportunities make this unit useful for lower speed functions or exact
timing functions with infrequent actions.
TIMER/COUNTER1 COUNT ENABLE
PSR1
CS10
CS11
CS12
PCK 64/32 MHz
0
CS13
14-BIT
T/C PRESCALER
T1CK
T1CK/2
T1CK/4
T1CK/8
T1CK/16
T1CK/32
T1CK/64
T1CK/128
T1CK/256
T1CK/512
T1CK/1024
T1CK/2048
T1CK/4096
T1CK/8192
T1CK/16384
CK
PCKE
T1CKATtiny25/45/85 [DATASHEET] 84
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Figure 12-2. Timer/Counter 1 Synchronization Register Block Diagram.
Timer/Counter1 and the prescaler allow running the CPU from any clock source while the prescaler is operating on
the fast 64 MHz (or 32 MHz in Low Speed Mode) PCK clock in the asynchronous mode.
Note that the system clock frequency must be lower than one third of the PCK frequency. The synchronization
mechanism of the asynchronous Timer/Counter1 needs at least two edges of the PCK when the system clock is
high. If the frequency of the system clock is too high, it is a risk that data or control values are lost.
The following Figure 12-3 shows the block diagram for Timer/Counter1.
8-BIT DATABUS
OCR1A OCR1A_SI
OCR1B OCR1B_SI TCNT_SO
OCR1C OCR1C_SI
TCCR1 TCCR1_SI
GTCCR GTCCR_SI
TCNT1 TCNT1_SI
OCF1A OCF1A_SI
OCF1B OCF1B_SI
TOV1 TOV1_SI TOV1_SO
OCF1B_SO
OCF1A_SO
TCNT1
S
A
S
A
PCKE
CK
PCK
IO-registers Input synchronization
registers
Timer/Counter1 Output synchronization
registers
SYNC
MODE
ASYNC
MODE
1 CK Delay
1 PCK Delay No Delay ~1 CK Delay
TCNT1
OCF1A
OCF1B
TOV1
1/2 CK Delay 1 CK Delay 1/2 CK Delay
1..2 PCK DelayATtiny25/45/85 [DATASHEET] 85
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Figure 12-3. Timer/Counter1 Block Diagram
Three status flags (overflow and compare matches) are found in the Timer/Counter Interrupt Flag Register - TIFR.
Control signals are found in the Timer/Counter Control Registers TCCR1 and GTCCR. The interrupt enable/disable
settings are found in the Timer/Counter Interrupt Mask Register - TIMSK.
The Timer/Counter1 contains three Output Compare Registers, OCR1A, OCR1B, and OCR1C as the data source
to be compared with the Timer/Counter1 contents. In normal mode the Output Compare functions are operational
with all three output compare registers. OCR1A determines action on the OC1A pin (PB1), and it can generate
Timer1 OC1A interrupt in normal mode and in PWM mode. Likewise, OCR1B determines action on the OC1B pin
(PB4) and it can generate Timer1 OC1B interrupt in normal mode and in PWM mode. OCR1C holds the
Timer/Counter maximum value, i.e. the clear on compare match value. In the normal mode an overflow interrupt
(TOV1) is generated when Timer/Counter1 counts from $FF to $00, while in the PWM mode the overflow interrupt
is generated when Timer/Counter1 counts either from $FF to $00 or from OCR1C to $00. The inverted PWM outputs
OC1A and OC1B are not connected in normal mode.
In PWM mode, OCR1A and OCR1B provide the data values against which the Timer Counter value is compared.
Upon compare match the PWM outputs (OC1A, OC1A, OC1B, OC1B) are generated. In PWM mode, the Timer
Counter counts up to the value specified in the output compare register OCR1C and starts again from $00. This
feature allows limiting the counter “full” value to a specified value, lower than $FF. Together with the many prescaler
options, flexible PWM frequency selection is provided. Table 12-3 on page 88 lists clock selection and
OCR1C values to obtain PWM frequencies from 20 kHz to 250 kHz in 10 kHz steps and from 250 kHz to 500 kHz
in 50 kHz steps. Higher PWM frequencies can be obtained at the expense of resolution.
8-BIT DATABUS
TIMER INT. FLAG
REGISTER (TIFR)
TIMER/COUNTER1
8-BIT COMPARATOR
T/C1 OUTPUT
COMPARE REGISTER
TIMER INT. MASK
REGISTER (TIMSK)
TIMER/COUNTER1
(TCNT1) T/C CLEAR T/C1 CONTROL
LOGIC
TOV1
OCF1B
OCIE1A
OCIE1B
TOIE1
TOIE0
OCF1A
OCF1B
TOV1
OCF1A
CK
PCK
T/C1 OVERFLOW
IRQ
T/C1 COMPARE
MATCH B IRQ
OC1A
(PB1)
T/C1 COMPARE
MATCH A IRQ
T/C CONTROL
REGISTER 1 (TCCR1) PWM1A
COM1B1
PWM1B
COM1B0
FOC1B
FOC1A
(OCR1A) (OCR1B) (OCR1C)
8-BIT COMPARATOR
T/C1 OUTPUT
COMPARE REGISTER TOV0
COM1A1
COM1A0
8-BIT COMPARATOR
T/C1 OUTPUT
COMPARE REGISTER
GLOBAL T/C CONTROL
REGISTER (GTCCR)
CS12
CS11
CS10
PSR1
CTC1
CS13
OC1A
(PB0)
OC1B
(PB4)
OC1B
(PB3)
DEAD TIME GENERATOR DEAD TIME GENERATORATtiny25/45/85 [DATASHEET] 86
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12.2.1 Timer/Counter1 Initialization for Asynchronous Mode
To set Timer/Counter1 in asynchronous mode first enable PLL and then wait 100 µs for PLL to stabilize. Next, poll
the PLOCK bit until it is set and then set the PCKE bit.
12.2.2 Timer/Counter1 in PWM Mode
When the PWM mode is selected, Timer/Counter1 and the Output Compare Register C - OCR1C form a dual 8-bit,
free-running and glitch-free PWM generator with outputs on the PB1(OC1A) and PB4(OC1B) pins and inverted
outputs on pins PB0(OC1A) and PB3(OC1B). As default non-overlapping times for complementary output pairs are
zero, but they can be inserted using a Dead Time Generator (see description on page 100).
Figure 12-4. The PWM Output Pair
When the counter value match the contents of OCR1A or OCR1B, the OC1A and OC1B outputs are set or cleared
according to the COM1A1/COM1A0 or COM1B1/COM1B0 bits in the Timer/Counter1 Control Register A - TCCR1,
as shown in Table 12-1.
Timer/Counter1 acts as an up-counter, counting from $00 up to the value specified in the output compare register
OCR1C, and starting from $00 up again. A compare match with OC1C will set an overflow interrupt flag (TOV1)
after a synchronization delay following the compare event.
Note that in PWM mode, writing to the Output Compare Registers OCR1A or OCR1B, the data value is first transferred
to a temporary location. The value is latched into OCR1A or OCR1B when the Timer/Counter reaches
OCR1C. This prevents the occurrence of odd-length PWM pulses (glitches) in the event of an unsynchronized
OCR1A or OCR1B. See Figure 12-5 for an example.
Table 12-1. Compare Mode Select in PWM Mode
COM1x1 COM1x0 Effect on Output Compare Pins
0 0 OC1x not connected.
OC1x not connected.
0 1 OC1x cleared on compare match. Set whenTCNT1 = $00.
OC1x set on compare match. Cleared when TCNT1 = $00.
1 0 OC1x cleared on compare match. Set when TCNT1 = $00.
OC1x not connected.
1 1 OC1x Set on compare match. Cleared when TCNT1= $00.
OC1x not connected.
PWM1x
PWM1x
t non-overlap=0 t non-overlap=0 x = A or BATtiny25/45/85 [DATASHEET] 87
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Figure 12-5. Effects of Unsynchronized OCR Latching
During the time between the write and the latch operation, a read from OCR1A or OCR1B will read the contents of
the temporary location. This means that the most recently written value always will read out of OCR1A or OCR1B.
When OCR1A or OCR1B contain $00 or the top value, as specified in OCR1C register, the output PB1(OC1A) or
PB4(OC1B) is held low or high according to the settings of COM1A1/COM1A0. This is shown in Table 12-2.
In PWM mode, the Timer Overflow Flag - TOV1 is set when the TCNT1 counts to the OCR1C value and the
TCNT1 is reset to $00. The Timer Overflow Interrupt1 is executed when TOV1 is set provided that Timer Overflow
Interrupt and global interrupts are enabled. This also applies to the Timer Output Compare flags and interrupts.
The frequency of the PWM will be Timer Clock 1 Frequency divided by (OCR1C value + 1). See the following
equation:
Resolution shows how many bits are required to express the value in the OCR1C register and can be calculated
using the following equation:
Table 12-2. PWM Outputs OCR1x = $00 or OCR1C, x = A or B
COM1x1 COM1x0 OCR1x Output OC1x Output OC1x
0 1 $00 L H
0 1 OCR1C H L
1 0 $00 L Not connected.
1 0 OCR1C H Not connected.
1 1 $00 H Not connected.
1 1 OCR1C L Not connected.
PWM Output OC1x
PWM Output OC1x
Unsynchronized OC1x Latch
Synchronized OC1x Latch
Counter Value
Compare Value
Counter Value
Compare Value
Compare Value changes
Glitch
Compare Value changes
f
PWM
f
TCK1
OCR1C + 1 = ------------------------------------
R = log2 OCR1C 1 ( ) +ATtiny25/45/85 [DATASHEET] 88
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Table 12-3. Timer/Counter1 Clock Prescale Select in the Asynchronous Mode
PWM Frequency Clock Selection CS1[3:0] OCR1C RESOLUTION
20 kHz PCK/16 0101 199 7.6
30 kHz PCK/16 0101 132 7.1
40 kHz PCK/8 0100 199 7.6
50 kHz PCK/8 0100 159 7.3
60 kHz PCK/8 0100 132 7.1
70 kHz PCK/4 0011 228 7.8
80 kHz PCK/4 0011 199 7.6
90 kHz PCK/4 0011 177 7.5
100 kHz PCK/4 0011 159 7.3
110 kHz PCK/4 0011 144 7.2
120 kHz PCK/4 0011 132 7.1
130 kHz PCK/2 0010 245 7.9
140 kHz PCK/2 0010 228 7.8
150 kHz PCK/2 0010 212 7.7
160 kHz PCK/2 0010 199 7.6
170 kHz PCK/2 0010 187 7.6
180 kHz PCK/2 0010 177 7.5
190 kHz PCK/2 0010 167 7.4
200 kHz PCK/2 0010 159 7.3
250 kHz PCK 0001 255 8.0
300 kHz PCK 0001 212 7.7
350 kHz PCK 0001 182 7.5
400 kHz PCK 0001 159 7.3
450 kHz PCK 0001 141 7.1
500 kHz PCK 0001 127 7.0ATtiny25/45/85 [DATASHEET] 89
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12.3 Register Description
12.3.1 TCCR1 – Timer/Counter1 Control Register
• Bit 7 – CTC1 : Clear Timer/Counter on Compare Match
When the CTC1 control bit is set (one), Timer/Counter1 is reset to $00 in the CPU clock cycle after a compare
match with OCR1C register value. If the control bit is cleared, Timer/Counter1 continues counting and is unaffected
by a compare match.
• Bit 6 – PWM1A: Pulse Width Modulator A Enable
When set (one) this bit enables PWM mode based on comparator OCR1A in Timer/Counter1 and the counter
value is reset to $00 in the CPU clock cycle after a compare match with OCR1C register value.
• Bits 5:4 – COM1A[1:0]: Comparator A Output Mode, Bits 1 and 0
The COM1A1 and COM1A0 control bits determine any output pin action following a compare match with compare
register A in Timer/Counter1. Since the output pin action is an alternative function to an I/O port, the corresponding
direction control bit must be set (one) in order to control an output pin.
In Normal mode, the COM1A1 and COM1A0 control bits determine the output pin actions that affect pin PB1
(OC1A) as described in Table 12-4. Note that OC1A is not connected in normal mode.
In PWM mode, these bits have different functions. Refer to Table 12-1 on page 86 for a detailed description.
• Bits 3:0 - CS1[3:0]: Clock Select Bits 3, 2, 1, and 0
The Clock Select bits 3, 2, 1, and 0 define the prescaling source of Timer/Counter1.
Bit 7 6 5 4 3 2 1 0
0x30 CTC1 PWM1A COM1A1 COM1A0 CS13 CS12 CS11 CS10 TCCR1
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Table 12-4. Comparator A Mode Select in Normal Mode
COM1A1 COM1A0 Description
0 0 Timer/Counter Comparator A disconnected from output pin OC1A.
0 1 Toggle the OC1A output line.
1 0 Clear the OC1A output line.
1 1 Set the OC1A output line
Table 12-5. Timer/Counter1 Prescale Select
CS13 CS12 CS11 CS10
Asynchronous
Clocking Mode
Synchronous
Clocking Mode
0 0 0 0 T/C1 stopped T/C1 stopped
0 0 0 1 PCK CK
0 0 1 0 PCK/2 CK/2
0 0 1 1 PCK/4 CK/4
0 1 0 0 PCK/8 CK/8
0 1 0 1 PCK/16 CK/16
0 1 1 0 PCK/32 CK/32ATtiny25/45/85 [DATASHEET] 90
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The Stop condition provides a Timer Enable/Disable function.
12.3.2 GTCCR – General Timer/Counter1 Control Register
• Bit 6 – PWM1B: Pulse Width Modulator B Enable
When set (one) this bit enables PWM mode based on comparator OCR1B in Timer/Counter1 and the counter
value is reset to $00 in the CPU clock cycle after a compare match with OCR1C register value.
• Bits 5:4 – COM1B[1:0]: Comparator B Output Mode, Bits 1 and 0
The COM1B1 and COM1B0 control bits determine any output pin action following a compare match with compare
register B in Timer/Counter1. Since the output pin action is an alternative function to an I/O port, the corresponding
direction control bit must be set (one) in order to control an output pin.
In Normal mode, the COM1B1 and COM1B0 control bits determine the output pin actions that affect pin PB4
(OC1B) as described in Table 12-6. Note that OC1B is not connected in normal mode.
In PWM mode, these bits have different functions. Refer to Table 12-1 on page 86 for a detailed description.
• Bit 3 – FOC1B: Force Output Compare Match 1B
Writing a logical one to this bit forces a change in the compare match output pin PB4 (OC1B) according to the values
already set in COM1B1 and COM1B0. If COM1B1 and COM1B0 written in the same cycle as FOC1B, the new
settings will be used. The Force Output Compare bit can be used to change the output pin value regardless of the
timer value. The automatic action programmed in COM1B1 and COM1B0 takes place as if a compare match had
0 1 1 1 PCK/64 CK/64
1 0 0 0 PCK/128 CK/128
1 0 0 1 PCK/256 CK/256
1 0 1 0 PCK/512 CK/512
1 0 1 1 PCK/1024 CK/1024
1 1 0 0 PCK/2048 CK/2048
1 1 0 1 PCK/4096 CK/4096
1 1 1 0 PCK/8192 CK/8192
1 1 1 1 PCK/16384 CK/16384
Table 12-5. Timer/Counter1 Prescale Select (Continued)
CS13 CS12 CS11 CS10
Asynchronous
Clocking Mode
Synchronous
Clocking Mode
Bit 7 6 5 4 3 2 1 0
0x2C TSM PWM1B COM1B1 COM1B0 FOC1B FOC1A PSR1 PSR0 GTCCR
Read/Write R/W R/W R/W R/W W W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Table 12-6. Comparator B Mode Select in Normal Mode
COM1B1 COM1B0 Description
0 0 Timer/Counter Comparator B disconnected from output pin OC1B.
0 1 Toggle the OC1B output line.
1 0 Clear the OC1B output line.
1 1 Set the OC1B output lineATtiny25/45/85 [DATASHEET] 91
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occurred, but no interrupt is generated. The FOC1B bit always reads as zero. FOC1B is not in use if PWM1B bit is
set.
• Bit 2 – FOC1A: Force Output Compare Match 1A
Writing a logical one to this bit forces a change in the compare match output pin PB1 (OC1A) according to the values
already set in COM1A1 and COM1A0. If COM1A1 and COM1A0 written in the same cycle as FOC1A, the new
settings will be used. The Force Output Compare bit can be used to change the output pin value regardless of the
timer value. The automatic action programmed in COM1A1 and COM1A0 takes place as if a compare match had
occurred, but no interrupt is generated. The FOC1A bit always reads as zero. FOC1A is not in use if PWM1A bit is
set.
• Bit 1 – PSR1 : Prescaler Reset Timer/Counter1
When this bit is set (one), the Timer/Counter prescaler (TCNT1 is unaffected) will be reset. The bit will be cleared
by hardware after the operation is performed. Writing a zero to this bit will have no effect. This bit will always read
as zero.
12.3.3 TCNT1 – Timer/Counter1
This 8-bit register contains the value of Timer/Counter1.
Timer/Counter1 is realized as an up counter with read and write access. Due to synchronization of the CPU,
Timer/Counter1 data written into Timer/Counter1 is delayed by one and half CPU clock cycles in synchronous
mode and at most one CPU clock cycles for asynchronous mode.
12.3.4 OCR1A –Timer/Counter1 Output Compare RegisterA
The output compare register A is an 8-bit read/write register.
The Timer/Counter Output Compare Register A contains data to be continuously compared with Timer/Counter1.
Actions on compare matches are specified in TCCR1. A compare match does only occur if Timer/Counter1 counts
to the OCR1A value. A software write that sets TCNT1 and OCR1A to the same value does not generate a compare
match.
A compare match will set the compare interrupt flag OCF1A after a synchronization delay following the compare
event.
12.3.5 OCR1B – Timer/Counter1 Output Compare RegisterB
The output compare register B is an 8-bit read/write register.
The Timer/Counter Output Compare Register B contains data to be continuously compared with Timer/Counter1.
Actions on compare matches are specified in TCCR1. A compare match does only occur if Timer/Counter1 counts
Bit 7 6 5 4 3 2 1 0
0x2F MSB LSB TCNT1
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x2E MSB LSB OCR1A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x2B MSB LSB OCR1B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 92
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to the OCR1B value. A software write that sets TCNT1 and OCR1B to the same value does not generate a compare
match.
A compare match will set the compare interrupt flag OCF1B after a synchronization delay following the compare
event.
12.3.6 OCR1C – Timer/Counter1 Output Compare RegisterC
The output compare register C is an 8-bit read/write register.
The Timer/Counter Output Compare Register C contains data to be continuously compared with Timer/Counter1.
A compare match does only occur if Timer/Counter1 counts to the OCR1C value. A software write that sets TCNT1
and OCR1C to the same value does not generate a compare match. If the CTC1 bit in TCCR1 is set, a compare
match will clear TCNT1.
This register has the same function in normal mode and PWM mode.
12.3.7 TIMSK – Timer/Counter Interrupt Mask Register
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
• Bit 6 – OCIE1A: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Compare
MatchA, interrupt is enabled. The corresponding interrupt at vector $003 is executed if a compare matchA occurs.
The Compare Flag in Timer/Counter1 is set (one) in the Timer/Counter Interrupt Flag Register.
• Bit 5 – OCIE1B: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Compare
MatchB, interrupt is enabled. The corresponding interrupt at vector $009 is executed if a compare matchB occurs.
The Compare Flag in Timer/Counter1 is set (one) in the Timer/Counter Interrupt Flag Register.
• Bit 2 – TOIE1: Timer/Counter1 Overflow Interrupt Enable
When the TOIE1 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Overflow interrupt
is enabled. The corresponding interrupt (at vector $004) is executed if an overflow in Timer/Counter1 occurs.
The Overflow Flag (Timer1) is set (one) in the Timer/Counter Interrupt Flag Register - TIFR.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
Bit 7 6 5 4 3 2 1 0
0x2D MSB LSB OCR1C
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 1 1 1 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
0x39 – OCIE1A OCIE1B OCIE0A OCIE0B TOIE1 TOIE0 – TIMSK
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 93
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12.3.8 TIFR – Timer/Counter Interrupt Flag Register
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
• Bit 6 – OCF1A: Output Compare Flag 1A
The OCF1A bit is set (one) when compare match occurs between Timer/Counter1 and the data value in OCR1A -
Output Compare Register 1A. OCF1A is cleared by hardware when executing the corresponding interrupt handling
vector. Alternatively, OCF1A is cleared, after synchronization clock cycle, by writing a logic one to the flag. When
the I-bit in SREG, OCIE1A, and OCF1A are set (one), the Timer/Counter1 A compare match interrupt is executed.
• Bit 5 – OCF1B: Output Compare Flag 1B
The OCF1B bit is set (one) when compare match occurs between Timer/Counter1 and the data value in OCR1B -
Output Compare Register 1A. OCF1B is cleared by hardware when executing the corresponding interrupt handling
vector. Alternatively, OCF1B is cleared, after synchronization clock cycle, by writing a logic one to the flag. When
the I-bit in SREG, OCIE1B, and OCF1B are set (one), the Timer/Counter1 B compare match interrupt is executed.
• Bit 2 – TOV1: Timer/Counter1 Overflow Flag
In normal mode (PWM1A=0 and PWM1B=0) the bit TOV1 is set (one) when an overflow occurs in Timer/Counter1.
The bit TOV1 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively,
TOV1 is cleared, after synchronization clock cycle, by writing a logical one to the flag.
In PWM mode (either PWM1A=1 or PWM1B=1) the bit TOV1 is set (one) when compare match occurs between
Timer/Counter1 and data value in OCR1C - Output Compare Register 1C.
When the SREG I-bit, and TOIE1 (Timer/Counter1 Overflow Interrupt Enable), and TOV1 are set (one), the
Timer/Counter1 Overflow interrupt is executed.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
Bit 7 6 5 4 3 2 1 0
0x38 – OCF1A OCF1B OCF0A OCF0B TOV1 TOV0 – TIFR
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 94
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12.3.9 PLLCSR – PLL Control and Status Register
• Bit 7 – LSM: Low Speed Mode
The high speed mode is enabled as default and the fast peripheral clock is 64 MHz, but the low speed mode can
be set by writing the LSM bit to one. Then the fast peripheral clock is scaled down to 32 MHz. The low speed mode
must be set, if the supply voltage is below 2.7 volts, because the Timer/Counter1 is not running fast enough on low
voltage levels. It is highly recommended that Timer/Counter1 is stopped whenever the LSM bit is changed.
Note, that LSM can not be set if PLLCLK is used as system clock.
• Bit 6:3 – Res : Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and always read as zero.
• Bit 2 – PCKE: PCK Enable
The PCKE bit change the Timer/Counter1 clock source. When it is set, the asynchronous clock mode is enabled
and fast 64 MHz (or 32 MHz in Low Speed Mode) PCK clock is used as Timer/Counter1 clock source. If this bit is
cleared, the synchronous clock mode is enabled, and system clock CK is used as Timer/Counter1 clock source.
This bit can be set only if PLLE bit is set. It is safe to set this bit only when the PLL is locked i.e the PLOCK bit is 1.
The bit PCKE can only be set, if the PLL has been enabled earlier.
• Bit 1 – PLLE: PLL Enable
When the PLLE is set, the PLL is started and if needed internal RC-oscillator is started as a PLL reference clock. If
PLL is selected as a system clock source the value for this bit is always 1.
• Bit 0 – PLOCK: PLL Lock Detector
When the PLOCK bit is set, the PLL is locked to the reference clock. The PLOCK bit should be ignored during initial
PLL lock-in sequence when PLL frequency overshoots and undershoots, before reaching steady state. The
steady state is obtained within 100 µs. After PLL lock-in it is recommended to check the PLOCK bit before enabling
PCK for Timer/Counter1.
Bit 7 6 5 4 3 2 1 0
0x27 LSM - - - - PCKE PLLE PLOCK PLLCSR
Read/Write R/W R R R R R/W R/W R
Initial value 0 0 0 0 0 0 0/1 0ATtiny25/45/85 [DATASHEET] 95
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13. 8-bit Timer/Counter1 in ATtiny15 Mode
The ATtiny15 compatibility mode is selected by writing the code “0011” to the CKSEL fuses (if any other code is
written, the Timer/Counter1 is working in normal mode). When selected the ATtiny15 compatibility mode provides
an ATtiny15 backward compatible prescaler and Timer/Counter. Furthermore, the clocking system has same clock
frequencies as in ATtiny15.
13.1 Timer/Counter1 Prescaler
Figure 13-1 shows an ATtiny15 compatible prescaler. It has two prescaler units, a 10-bit prescaler for the system
clock (CK) and a 3-bit prescaler for the fast peripheral clock (PCK). The clocking system of the Timer/Counter1 is
always synchronous in the ATtiny15 compatibility mode, because the same RC Oscillator is used as a PLL clock
source (generates the input clock for the prescaler) and the AVR core.
Figure 13-1. Timer/Counter1 Prescaler
The same clock selections as in ATtiny15 can be chosen for Timer/Counter1 from the output multiplexer, because
the frequency of the fast peripheral clock is 25.6 MHz and the prescaler is similar in the ATtiny15 compatibility
mode. The clock selections are PCK, PCK/2, PCK/4, PCK/8, CK, CK/2, CK/4, CK/8, CK/16, CK/32, CK/64,
CK/128, CK/256, CK/512, CK/1024 and stop.
13.2 Counter and Compare Units
Figure 13-2 shows Timer/Counter 1 synchronization register block diagram and synchronization delays in between
registers. Note that all clock gating details are not shown in the figure. The Timer/Counter1 register values go
through the internal synchronization registers, which cause the input synchronization delay, before affecting the
counter operation. The registers TCCR1, GTCCR, OCR1A and OCR1C can be read back right after writing the
register. The read back values are delayed for the Timer/Counter1 (TCNT1) register and flags (OCF1A and TOV1),
because of the input and output synchronization.
The Timer/Counter1 features a high resolution and a high accuracy usage with the lower prescaling opportunities.
It can also support an accurate, high speed, 8-bit Pulse Width Modulator (PWM) using clock speeds up to 25.6
MHz. In this mode, Timer/Counter1 and the Output Compare Registers serve as a stand-alone PWM. Refer to
“Timer/Counter1 in PWM Mode” on page 97 for a detailed description on this function. Similarly, the high prescaling
opportunities make this unit useful for lower speed functions or exact timing functions with infrequent actions.
TIMER/COUNTER1 COUNT ENABLE
PSR1
CS10
CS11
CS12
PCK (25.6 MHz)
0
CS13
3-BIT T/C PRESCALER PCK PCK/2 PCK/4 PCK/8
CK/2
CK/4
CK/8
CK/16
CK/32
CK/64
CK/128
CK/256
CK/512
CK/1024
10-BIT T/C PRESCALER
CK (1.6 MHz)
CK
CLEAR CLEARATtiny25/45/85 [DATASHEET] 96
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Figure 13-2. Timer/Counter 1 Synchronization Register Block Diagram.
Timer/Counter1 and the prescaler allow running the CPU from any clock source while the prescaler is operating on
the fast 25.6 MHz PCK clock in the asynchronous mode.
The following Figure 13-3 shows the block diagram for Timer/Counter1.
8-BIT DATABUS
OCR1A OCR1A_SI
OCR1C OCR1C_SI TCNT_SO
TCCR1 TCCR1_SI
GTCCR GTCCR_SI
TCNT1 TCNT1_SI
OCF1A OCF1A_SI
TOV1 TOV1_SI TOV1_SO
OCF1A_SO
TCNT1
S
A
S
A
PCKE
CK
PCK
IO-registers Input synchronization
registers
Timer/Counter1 Output synchronization
registers
SYNC
MODE
ASYNC
MODE
1 PCK Delay No Delay ~1 CK Delay
1PCK Delay No Delay
TCNT1
OCF1A
TOV1
1..2 PCK Delay
1..2 PCK Delay ~1 CK DelayATtiny25/45/85 [DATASHEET] 97
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Figure 13-3. Timer/Counter1 Block Diagram
Two status flags (overflow and compare match) are found in the Timer/Counter Interrupt Flag Register - TIFR.
Control signals are found in the Timer/Counter Control Registers TCCR1 and GTCCR. The interrupt enable/disable
settings are found in the Timer/Counter Interrupt Mask Register - TIMSK.
The Timer/Counter1 contains two Output Compare Registers, OCR1A and OCR1C as the data source to be compared
with the Timer/Counter1 contents. In normal mode the Output Compare functions are operational with
OCR1A only. OCR1A determines action on the OC1A pin (PB1), and it can generate Timer1 OC1A interrupt in normal
mode and in PWM mode. OCR1C holds the Timer/Counter maximum value, i.e. the clear on compare match
value. In the normal mode an overflow interrupt (TOV1) is generated when Timer/Counter1 counts from $FF to
$00, while in the PWM mode the overflow interrupt is generated when the Timer/Counter1 counts either from $FF
to $00 or from OCR1C to $00.
In PWM mode, OCR1A provides the data values against which the Timer Counter value is compared. Upon compare
match the PWM outputs (OC1A) is generated. In PWM mode, the Timer Counter counts up to the value
specified in the output compare register OCR1C and starts again from $00. This feature allows limiting the counter
“full” value to a specified value, lower than $FF. Together with the many prescaler options, flexible PWM frequency
selection is provided. Table 12-3 on page 88 lists clock selection and OCR1C values to obtain PWM frequencies
from 20 kHz to 250 kHz in 10 kHz steps and from 250 kHz to 500 kHz in 50 kHz steps. Higher PWM frequencies
can be obtained at the expense of resolution.
13.2.1 Timer/Counter1 in PWM Mode
When the PWM mode is selected, Timer/Counter1 and the Output Compare Register A - OCR1A form an 8-bit,
free-running and glitch-free PWM generator with output on the PB1(OC1A).
8-BIT DATABUS
TIMER INT. FLAG
REGISTER (TIFR)
TIMER/COUNTER1
8-BIT COMPARATOR
T/C1 OUTPUT
COMPARE REGISTER
TIMER INT. MASK
REGISTER (TIMSK)
TIMER/COUNTER1
(TCNT1) T/C CLEAR T/C1 CONTROL
LOGIC
TOV1
OCIE1A
TOIE1
TOIE0
OCF1A
TOV1
OCF1A
CK
PCK
T/C1 OVERFLOW
IRQ
OC1A
(PB1)
T/C1 COMPARE
MATCH A IRQ
GLOBAL T/C CONTROL
REGISTER 2 (GTCCR)
PWM1A
FOC1A
(OCR1A) (OCR1C)
8-BIT COMPARATOR
T/C1 OUTPUT
COMPARE REGISTER TOV0
COM1A1
COM1A0
T/C CONTROL
REGISTER 1 (TCCR1)
CTC1
CS13
CS12
CS11
CS10
PSR1ATtiny25/45/85 [DATASHEET] 98
2586Q–AVR–08/2013
When the counter value match the content of OCR1A, the OC1A and output is set or cleared according to the
COM1A1/COM1A0 bits in the Timer/Counter1 Control Register A - TCCR1, as shown in Table 13-1.
Timer/Counter1 acts as an up-counter, counting from $00 up to the value specified in the output compare register
OCR1C, and starting from $00 up again. A compare match with OCR1C will set an overflow interrupt flag (TOV1)
after a synchronization delay following the compare event.
Note that in PWM mode, writing to the Output Compare Register OCR1A, the data value is first transferred to a
temporary location. The value is latched into OCR1A when the Timer/Counter reaches OCR1C. This prevents the
occurrence of odd-length PWM pulses (glitches) in the event of an unsynchronized OCR1A. See Figure 13-4 for an
e xample.
Figure 13-4. Effects of Unsynchronized OCR Latching
During the time between the write and the latch operation, a read from OCR1A will read the contents of the temporary
location. This means that the most recently written value always will read out of OCR1A.
When OCR1A contains $00 or the top value, as specified in OCR1C register, the output PB1(OC1A) is held low or
high according to the settings of COM1A1/COM1A0. This is shown in Table 13-2.
Table 13-1. Compare Mode Select in PWM Mode
COM1A1 COM1A0 Effect on Output Compare Pin
0 0 OC1A not connected.
0 1 OC1A not connected.
1 0 OC1A cleared on compare match. Set when TCNT1 = $00.
1 1 OC1A set on compare match. Cleared when TCNT1 = $00.
Table 13-2. PWM Outputs OCR1A = $00 or OCR1C
COM1A1 COM1A0 OCR1A Output OC1A
0 1 $00 L
0 1 OCR1C H
1 0 $00 L
PWM Output OC1A
PWM Output OC1A
Unsynchronized OC1A Latch
Synchronized OC1A Latch
Counter Value
Compare Value
Counter Value
Compare Value
Compare Value changes
Glitch
Compare Value changesATtiny25/45/85 [DATASHEET] 99
2586Q–AVR–08/2013
In PWM mode, the Timer Overflow Flag - TOV1 is set when the TCNT1 counts to the OCR1C value and the
TCNT1 is reset to $00. The Timer Overflow Interrupt1 is executed when TOV1 is set provided that Timer Overflow
Interrupt and global interrupts are enabled. This also applies to the Timer Output Compare flags and interrupts.
The PWM frequency can be derived from the timer/counter clock frequency using the following equation:
The duty cycle of the PWM waveform can be calculated using the following equation:
...where TPCK is the period of the fast peripheral clock (1/25.6 MHz = 39.1 ns).
Resolution indicates how many bits are required to express the value in the OCR1C register. It can be calculated
using the following equation:
1 0 OCR1C H
1 1 $00 H
1 1 OCR1C L
Table 13-3. Timer/Counter1 Clock Prescale Select in the Asynchronous Mode
PWM Frequency Clock Selection CS1[3:0] OCR1C RESOLUTION
20 kHz PCK/16 0101 199 7.6
30 kHz PCK/16 0101 132 7.1
40 kHz PCK/8 0100 199 7.6
50 kHz PCK/8 0100 159 7.3
60 kHz PCK/8 0100 132 7.1
70 kHz PCK/4 0011 228 7.8
80 kHz PCK/4 0011 199 7.6
90 kHz PCK/4 0011 177 7.5
100 kHz PCK/4 0011 159 7.3
110 kHz PCK/4 0011 144 7.2
120 kHz PCK/4 0011 132 7.1
130 kHz PCK/2 0010 245 7.9
140 kHz PCK/2 0010 228 7.8
150 kHz PCK/2 0010 212 7.7
Table 13-2. PWM Outputs OCR1A = $00 or OCR1C
COM1A1 COM1A0 OCR1A Output OC1A
f f
TCK1
OCR1C + 1 = -----------------------------------
D OCR1A 1 + TTCK1 TPCK –
OCR1C 1 + TTCK1 = ----------------------------------------------------------------------------
R = log2 OCR1C 1 ( ) +ATtiny25/45/85 [DATASHEET] 100
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13.3 Register Description
13.3.1 TCCR1 – Timer/Counter1 Control Register
• Bit 7 – CTC1 : Clear Timer/Counter on Compare Match
When the CTC1 control bit is set (one), Timer/Counter1 is reset to $00 in the CPU clock cycle after a compare
match with OCR1A register. If the control bit is cleared, Timer/Counter1 continues counting and is unaffected by a
compare match.
• Bit 6 – PWM1A: Pulse Width Modulator A Enable
When set (one) this bit enables PWM mode based on comparator OCR1A in Timer/Counter1 and the counter
value is reset to $00 in the CPU clock cycle after a compare match with OCR1C register value.
• Bits 5:4 – COM1A[1:0]: Comparator A Output Mode, Bits 1 and 0
The COM1A1 and COM1A0 control bits determine any output pin action following a compare match with compare
register A in Timer/Counter1. Output pin actions affect pin PB1 (OC1A). Since this is an alternative function to an
I/O port, the corresponding direction control bit must be set (one) in order to control an output pin.
In PWM mode, these bits have different functions. Refer to Table 13-1 on page 98 for a detailed description.
160 kHz PCK/2 0010 199 7.6
170 kHz PCK/2 0010 187 7.6
180 kHz PCK/2 0010 177 7.5
190 kHz PCK/2 0010 167 7.4
200 kHz PCK/2 0010 159 7.3
250 kHz PCK 0001 255 8.0
300 kHz PCK 0001 212 7.7
350 kHz PCK 0001 182 7.5
400 kHz PCK 0001 159 7.3
450 kHz PCK 0001 141 7.1
500 kHz PCK 0001 127 7.0
Table 13-3. Timer/Counter1 Clock Prescale Select in the Asynchronous Mode (Continued)
PWM Frequency Clock Selection CS1[3:0] OCR1C RESOLUTION
Bit 7 6 5 4 3 2 1 0
0x30 CTC1 PWM1A COM1A1 COM1A0 CS13 CS12 CS11 CS10 TCCR1A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Table 13-4. Comparator A Mode Select
COM1A1 COM1A0 Description
0 0 Timer/Counter Comparator A disconnected from output pin OC1A.
0 1 Toggle the OC1A output line.
1 0 Clear the OC1A output line.
1 1 Set the OC1A output lineATtiny25/45/85 [DATASHEET] 101
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• Bits 3:0 – CS1[3:0]: Clock Select Bits 3, 2, 1, and 0
The Clock Select bits 3, 2, 1, and 0 define the prescaling source of Timer/Counter1.
The Stop condition provides a Timer Enable/Disable function.
13.3.2 GTCCR – General Timer/Counter1 Control Register
• Bit 2 – FOC1A: Force Output Compare Match 1A
Writing a logical one to this bit forces a change in the compare match output pin PB1 (OC1A) according to the values
already set in COM1A1 and COM1A0. If COM1A1 and COM1A0 written in the same cycle as FOC1A, the new
settings will be used. The Force Output Compare bit can be used to change the output pin value regardless of the
timer value. The automatic action programmed in COM1A1 and COM1A0 takes place as if a compare match had
occurred, but no interrupt is generated. The FOC1A bit always reads as zero. FOC1A is not in use if PWM1A bit is
set.
• Bit 1 – PSR1 : Prescaler Reset Timer/Counter1
When this bit is set (one), the Timer/Counter prescaler (TCNT1 is unaffected) will be reset. The bit will be cleared
by hardware after the operation is performed. Writing a zero to this bit will have no effect. This bit will always read
as zero.
Table 13-5. Timer/Counter1 Prescale Select
CS13 CS12 CS11 CS10 T/C1 Clock
0 0 0 0 T/C1 stopped
0 0 0 1 PCK
0 0 1 0 PCK/2
0 0 1 1 PCK/4
0 1 0 0 PCK/8
0 1 0 1 CK
0 1 1 0 CK/2
0 1 1 1 CK/4
1 0 0 0 CK/8
1 0 0 1 CK/16
1 0 1 0 CK/32
1 0 1 1 CK/64
1 1 0 0 CK/128
1 1 0 1 CK/256
1 1 1 0 CK/512
1 1 1 1 CK/1024
Bit 7 6 5 4 3 2 1 0
0x2C TSM PWM1B COM1B1 COM1B0 FOC1B FOC1A PSR1 PSR0 GTCCR
Read/Write R/W R/W R/W R/W W W R/W R/W
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 102
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13.3.3 TCNT1 – Timer/Counter1
This 8-bit register contains the value of Timer/Counter1.
Timer/Counter1 is realized as an up counter with read and write access. Due to synchronization of the CPU,
Timer/Counter1 data written into Timer/Counter1 is delayed by one CPU clock cycle in synchronous mode and at
most two CPU clock cycles for asynchronous mode.
13.3.4 OCR1A – Timer/Counter1 Output Compare RegisterA
The output compare register A is an 8-bit read/write register.
The Timer/Counter Output Compare Register A contains data to be continuously compared with Timer/Counter1.
Actions on compare matches are specified in TCCR1. A compare match does only occur if Timer/Counter1 counts
to the OCR1A value. A software write that sets TCNT1 and OCR1A to the same value does not generate a compare
match.
A compare match will set the compare interrupt flag OCF1A after a synchronization delay following the compare
event.
13.3.5 OCR1C – Timer/Counter1 Output Compare Register C
The Output Compare Register B - OCR1B from ATtiny15 is replaced with the output compare register C - OCR1C
that is an 8-bit read/write register. This register has the same function as the Output Compare Register B in
ATtiny15.
The Timer/Counter Output Compare Register C contains data to be continuously compared with Timer/Counter1.
A compare match does only occur if Timer/Counter1 counts to the OCR1C value. A software write that sets TCNT1
and OCR1C to the same value does not generate a compare match. If the CTC1 bit in TCCR1 is set, a compare
match will clear TCNT1.
13.3.6 TIMSK – Timer/Counter Interrupt Mask Register
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
Bit 7 6 5 4 3 2 1 0
0x2F MSB LSB TCNT1
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x2E MSB LSB OCR1A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x2D MSB LSB OCR1C
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 1 1 1 1 1 1 1 1
Bit 7 6 5 4 3 2 1 0
0x39 – OCIE1A OCIE1B OCIE0A OCIE0B TOIE1 TOIE0 – TIMSK
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 103
2586Q–AVR–08/2013
• Bit 6 – OCIE1A: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Compare
MatchA, interrupt is enabled. The corresponding interrupt at vector $003 is executed if a compare matchA occurs.
The Compare Flag in Timer/Counter1 is set (one) in the Timer/Counter Interrupt Flag Register.
• Bit 2 – TOIE1: Timer/Counter1 Overflow Interrupt Enable
When the TOIE1 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Overflow interrupt
is enabled. The corresponding interrupt (at vector $004) is executed if an overflow in Timer/Counter1 occurs.
The Overflow Flag (Timer1) is set (one) in the Timer/Counter Interrupt Flag Register - TIFR.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
13.3.7 TIFR – Timer/Counter Interrupt Flag Register
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
• Bit 6 – OCF1A: Output Compare Flag 1A
The OCF1A bit is set (one) when compare match occurs between Timer/Counter1 and the data value in OCR1A -
Output Compare Register 1A. OCF1A is cleared by hardware when executing the corresponding interrupt handling
vector. Alternatively, OCF1A is cleared, after synchronization clock cycle, by writing a logic one to the flag. When
the I-bit in SREG, OCIE1A, and OCF1A are set (one), the Timer/Counter1 A compare match interrupt is executed.
• Bit 2 – TOV1: Timer/Counter1 Overflow Flag
The bit TOV1 is set (one) when an overflow occurs in Timer/Counter1. TOV1 is cleared by hardware when executing
the corresponding interrupt handling vector. Alternatively, TOV1 is cleared, after synchronization clock cycle,
by writing a logical one to the flag. When the SREG I-bit, and TOIE1 (Timer/Counter1 Overflow Interrupt Enable),
and TOV1 are set (one), the Timer/Counter1 Overflow interrupt is executed.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
13.3.8 PLLCSR – PLL Control and Status Register
• Bits 6:3 – Res : Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and always read as zero.
• Bit 2 – PCKE: PCK Enable
The bit PCKE is always set in the ATtiny15 compatibility mode.
• Bit 1 – PLLE: PLL Enable
The PLL is always enabled in the ATtiny15 compatibility mode.
Bit 7 6 5 4 3 2 1 0
0x38 – OCF1A OCF1B OCF0A OCF0B TOV1 TOV0 – TIFR
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x27 LSM – – – – PCKE PLLE PLOCK PLLCSR
Read/Write R/W R R R R R/W R/W R
Initial value 0 0 0 0 0 0 0/1 0ATtiny25/45/85 [DATASHEET] 104
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• Bit 0 – PLOCK: PLL Lock Detector
When the PLOCK bit is set, the PLL is locked to the reference clock. The PLOCK bit should be ignored during initial
PLL lock-in sequence when PLL frequency overshoots and undershoots, before reaching steady state. The
steady state is obtained within 100 µs. After PLL lock-in it is recommended to check the PLOCK bit before enabling
PCK for Timer/Counter1.ATtiny25/45/85 [DATASHEET] 105
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14. Dead Time Generator
The Dead Time Generator is provided for the Timer/Counter1 PWM output pairs to allow driving external power
control switches safely. The Dead Time Generator is a separate block that can be connected to Timer/Counter1
and it is used to insert dead times (non-overlapping times) for the Timer/Counter1 complementary output pairs
(OC1A-OC1A and OC1B-OC1B). The sharing of tasks is as follows: the timer/counter generates the PWM output
and the Dead Time Generator generates the non-overlapping PWM output pair from the timer/counter PWM signal.
Two Dead Time Generators are provided, one for each PWM output. The non-overlap time is adjustable and the
PWM output and it’s complementary output are adjusted separately, and independently for both PWM outputs.
Figure 14-1. Timer/Counter1 & Dead Time Generators
The dead time generation is based on the 4-bit down counters that count the dead time, as shown in Figure 46.
There is a dedicated prescaler in front of the Dead Time Generator that can divide the Timer/Counter1 clock (PCK
or CK) by 1, 2, 4 or 8. This provides for large range of dead times that can be generated. The prescaler is controlled
by two control bits DTPS1[1:0] from the I/O register at address 0x23. The block has also a rising and falling
edge detector that is used to start the dead time counting period. Depending on the edge, one of the transitions on
the rising edges, OC1x or OC1x is delayed until the counter has counted to zero. The comparator is used to compare
the counter with zero and stop the dead time insertion when zero has been reached. The counter is loaded
with a 4-bit DT1xH or DT1xL value from DT1x I/O register, depending on the edge of the PWM generator output
when the dead time insertion is started.
Figure 14-2. Dead Time Generator
The length of the counting period is user adjustable by selecting the dead time prescaler setting in 0x23 register,
and selecting then the dead time value in I/O register DT1x. The DT1x register consists of two 4-bit fields, DT1xH
and DT1xL that control the dead time periods of the PWM output and its’ complementary output separately. Thus
TIMER/COUNTER1
OC1A OC1A OC1B OC1B
DEAD TIME GENERATOR
PWM GENERATOR
PCKE
T15M
PCK
CK
DT1AH DT1BH
DEAD TIME GENERATOR
PWM1A PWM1B
DT1AL DT1BL
CLOCK CONTROL
OC1x
OC1x
T/C1 CLOCK
PWM1x
4-BIT COUNTER
COMPARATOR
DT1xH
DT1xL
DT1x
I/O REGISTER
DEAD TIME
PRESCALER
DTPS1[1:0]ATtiny25/45/85 [DATASHEET] 106
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the rising edge of OC1x and OC1x can have different dead time periods. The dead time is adjusted as the number
of prescaled dead time generator clock cycles.
Figure 14-3. The Complementary Output Pair
14.1 Register Description
14.1.1 DTPS1 – Timer/Counter1 Dead Time Prescaler Register 1
The dead time prescaler register, DTPS1 is a 2-bit read/write register.
• Bits 1:0 – DTPS1[1:0]: Dead Time Prescaler
The dedicated Dead Time prescaler in front of the Dead Time Generator can divide the Timer/Counter1 clock (PCK
or CK) by 1, 2, 4 or 8 providing a large range of dead times that can be generated. The Dead Time prescaler is
controlled by two bits DTPS1[1:0] from the Dead Time Prescaler register. These bits define the division factor of
the Dead Time prescaler. The division factors are given in table 46.
OC1x
x = A or B
t non-overlap / rising edge t non-overlap / falling edge
OC1x
PWM1x
Bit 7 6 5 4 3 2 1 0
0x23 DTPS11 DTPS10 DTPS1
Read/Write R R R R R R R/W R/W
Initial value 0 0 0 0 0 0 0 0
Table 14-1. Division factors of the Dead Time prescaler
DTPS11 DTPS10 Prescaler divides the T/C1 clock by
0 0 1x (no division)
0 1 2x
1 0 4x
1 1 8xATtiny25/45/85 [DATASHEET] 107
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14.1.2 DT1A – Timer/Counter1 Dead Time A
The dead time value register A is an 8-bit read/write register.
The dead time delay of is adjusted by the dead time value register, DT1A. The register consists of two fields,
DT1AH[3:0] and DT1AL[3:0], one for each complementary output. Therefore a different dead time delay can be
adjusted for the rising edge of OC1A and the rising edge of OC1A.
• Bits 7:4 – DT1AH[3:0]: Dead Time Value for OC1A Output
The dead time value for the OC1A output. The dead time delay is set as a number of the prescaled timer/counter
clocks. The minimum dead time is zero and the maximum dead time is the prescaled time/counter clock period
multiplied by 15.
• Bits 3:0 – DT1AL[3:0]: Dead Time Value for OC1A Output
The dead time value for the OC1A output. The dead time delay is set as a number of the prescaled timer/counter
clocks. The minimum dead time is zero and the maximum dead time is the prescaled time/counter clock period
multiplied by 15.
14.1.3 DT1B – Timer/Counter1 Dead Time B
The dead time value register Bis an 8-bit read/write register.
The dead time delay of is adjusted by the dead time value register, DT1B. The register consists of two fields,
DT1BH[3:0] and DT1BL[3:0], one for each complementary output. Therefore a different dead time delay can be
adjusted for the rising edge of OC1A and the rising edge of OC1A.
• Bits 7:4 – DT1BH[3:0]: Dead Time Value for OC1B Output
The dead time value for the OC1B output. The dead time delay is set as a number of the prescaled timer/counter
clocks. The minimum dead time is zero and the maximum dead time is the prescaled time/counter clock period
multiplied by 15.
• Bits 3:0 – DT1BL[3:0]: Dead Time Value for OC1B Output
The dead time value for the OC1B output. The dead time delay is set as a number of the prescaled timer/counter
clocks. The minimum dead time is zero and the maximum dead time is the prescaled time/counter clock period
multiplied by 15.
Bit 7 6 5 4 3 2 1 0
0x25 DT1AH3 DT1AH2 DT1AH1 DT1AH0 DT1AL3 DT1AL2 DT1AL1 DT1AL0 DT1A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
0x24 DT1BH3 DT1BH2 DT1BH1 DT1BH0 DT1BL3 DT1BL2 DT1BL1 DT1BL0 DT1B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0ATtiny25/45/85 [DATASHEET] 108
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15. USI – Universal Serial Interface
15.1 Features
• Two-wire Synchronous Data Transfer (Master or Slave)
• Three-wire Synchronous Data Transfer (Master or Slave)
• Data Received Interrupt
• Wakeup from Idle Mode
• Wake-up from All Sleep Modes In Two-wire Mode
• Two-wire Start Condition Detector with Interrupt Capability
15.2 Overview
The Universal Serial Interface (USI), provides the basic hardware resources needed for serial communication.
Combined with a minimum of control software, the USI allows significantly higher transfer rates and uses less code
space than solutions based on software only. Interrupts are included to minimize the processor load.
A simplified block diagram of the USI is shown in Figure 15-1 For actual placement of I/O pins refer to “Pinout
ATtiny25/45/85” on page 2. Device-specific I/O Register and bit locations are listed in the “Register Descriptions”
on page 115.
Figure 15-1. Universal Serial Interface, Block Diagram
The 8-bit USI Data Register (USIDR) contains the incoming and outgoing data. It is directly accessible via the data
bus but a copy of the contents is also placed in the USI Buffer Register (USIBR) where it can be retrieved later. If
reading the USI Data Register directly, the register must be read as quickly as possible to ensure that no data is
lost.
The most significant bit of the USI Data Register is connected to one of two output pins (depending on the mode
configuration, see “USICR – USI Control Register” on page 116). There is a transparent latch between the output
of the USI Data Register and the output pin, which delays the change of data output to the opposite clock edge of
the data input sampling. The serial input is always sampled from the Data Input (DI) pin independent of the
configuration. DATA BUS
USIPF
USICS1
USICS0
USICLK
USITC
USIOIF USIOIE
USISIF
USIDC
USISIE Bit7
USIWM1
USIWM0
Two-wire
Clock
Control Unit
DO (Output only)
DI/SDA (Input/Open Drain)
USCK/SCL (Input/Open Drain)
4-bit Counter
USIDR
USISR
D Q
LE
USICR
CLOCK
HOLD
TIM0 COMP
Bit0
[1]
3
0
1
2
3
0
1
2
0
1
2
USIBRATtiny25/45/85 [DATASHEET] 109
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The 4-bit counter can be both read and written via the data bus, and it can generate an overflow interrupt. Both the
USI Data Register and the counter are clocked simultaneously by the same clock source. This allows the counter
to count the number of bits received or transmitted and generate an interrupt when the transfer is complete. Note
that when an external clock source is selected the counter counts both clock edges. This means the counter registers
the number of clock edges and not the number of data bits. The clock can be selected from three different
sources: The USCK pin, Timer/Counter0 Compare Match or from software.
The two-wire clock control unit can be configured to generate an interrupt when a start condition has been detected
on the two-wire bus. It can also be set to generate wait states by holding the clock pin low after a start condition is
detected, or after the counter overflows.
15.3 Functional Descriptions
15.3.1 Three-wire Mode
The USI three-wire mode is compliant to the Serial Peripheral Interface (SPI) mode 0 and 1, but does not have the
slave select (SS) pin functionality. However, this feature can be implemented in software, if required. Pin names
used in this mode are DI, DO, and USCK.
Figure 15-2. Three-wire Mode Operation, Simplified Diagram
Figure 15-2 shows two USI units operating in three-wire mode, one as Master and one as Slave. The two USI Data
Registers are interconnected in such way that after eight USCK clocks, the data in each register has been interchanged.
The same clock also increments the USI’s 4-bit counter. The Counter Overflow (interrupt) Flag, or
USIOIF, can therefore be used to determine when a transfer is completed. The clock is generated by the Master
device software by toggling the USCK pin via the PORTB register or by writing a one to bit USITC bit in USICR.
SLAVE
MASTER
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
DO
DI
USCK
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
DO
DI
USCK
PORTxnATtiny25/45/85 [DATASHEET] 110
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Figure 15-3. Three-Wire Mode, Timing Diagram
The three-wire mode timing is shown in Figure 15-3 At the top of the figure is a USCK cycle reference. One bit is
shifted into the USI Data Register (USIDR) for each of these cycles. The USCK timing is shown for both external
clock modes. In external clock mode 0 (USICS0 = 0), DI is sampled at positive edges, and DO is changed (USI
Data Register is shifted by one) at negative edges. In external clock mode 1 (USICS0 = 1) the opposite edges with
respect to mode 0 are used. In other words, data is sampled at negative and changes the output at positive edges.
The USI clock modes corresponds to the SPI data mode 0 and 1.
Referring to the timing diagram (Figure 15-3), a bus transfer involves the following steps:
1. The slave and master devices set up their data outputs and, depending on the protocol used, enable their
output drivers (mark A and B). The output is set up by writing the data to be transmitted to the USI Data
Register. The output is enabled by setting the corresponding bit in the Data Direction Register of Port B.
Note that there is not a preferred order of points A and B in the figure, but both must be at least one half
USCK cycle before point C, where the data is sampled. This is in order to ensure that the data setup
requirement is satisfied. The 4-bit counter is reset to zero.
2. The master software generates a clock pulse by toggling the USCK line twice (C and D). The bit values on
the data input (DI) pins are sampled by the USI on the first edge (C), and the data output is changed on
the opposite edge (D). The 4-bit counter will count both edges.
3. Step 2. is repeated eight times for a complete register (byte) transfer.
4. After eight clock pulses (i.e., 16 clock edges) the counter will overflow and indicate that the transfer has
been completed. If USI Buffer Registers are not used the data bytes that have been transferred must now
be processed before a new transfer can be initiated. The overflow interrupt will wake up the processor if it
is set to Idle mode. Depending of the protocol used the slave device can now set its output to high
impedance.
15.3.2 SPI Master Operation Example
The following code demonstrates how to use the USI as an SPI Master:
SPITransfer:
out USIDR,r16
ldi r16,(1< 2 CPU clock cycles for fck < 12 MHz, 3 CPU clock cycles for fck >= 12 MHz
High: > 2 CPU clock cycles for fck < 12 MHz, 3 CPU clock cycles for fck >= 12 MHz
20.5.1 Serial Programming Algorithm
When writing serial data to the ATtiny25/45/85, data is clocked on the rising edge of SCK.
When reading data from the ATtiny25/45/85, data is clocked on the falling edge of SCK. See Figure 21-4 and Figure
21-5 for timing details.
Table 20-10. Pin Mapping Serial Programming
Symbol Pins I/O Description
MOSI PB0 I Serial Data in
MISO PB1 O Serial Data out
SCK PB2 I Serial Clock
VCC
GND
SCK
MISO
MOSI
RESET
+1.8 - 5.5VATtiny25/45/85 [DATASHEET] 152
2586Q–AVR–08/2013
To program and verify the ATtiny25/45/85 in the Serial Programming mode, the following sequence is recommended
(see four byte instruction formats in Table 20-12):
1. Power-up sequence: apply power between VCC and GND while RESET and SCK are set to “0”
– In some systems, the programmer can not guarantee that SCK is held low during power-up. In this
case, RESET must be given a positive pulse after SCK has been set to '0'. The duration of the pulse
must be at least tRST plus two CPU clock cycles. See Table 21-4 on page 165 for minimum pulse width
on RESET pin, tRST
2. Wait for at least 20 ms and enable serial programming by sending the Programming Enable serial instruction
to pin MOSI.
3. The serial programming instructions will not work if the communication is out of synchronization. When in
sync. the second byte (0x53), will echo back when issuing the third byte of the Programming Enable
instruction. Whether the echo is correct or not, all four bytes of the instruction must be transmitted. If the
0x53 did not echo back, give RESET a positive pulse and issue a new Programming Enable command.
4. The Flash is programmed one page at a time. The memory page is loaded one byte at a time by supplying
the 5 LSB of the address and data together with the Load Program memory Page instruction. To ensure
correct loading of the page, the data low byte must be loaded before data high byte is applied for a given
address. The Program memory Page is stored by loading the Write Program memory Page instruction
with the 6 MSB of the address. If polling (RDY/BSY) is not used, the user must wait at least tWD_FLASH
before issuing the next page. (See Table 20-11.) Accessing the serial programming interface before the
Flash write operation completes can result in incorrect programming.
5. A: The EEPROM array is programmed one byte at a time by supplying the address and data together with
the appropriate Write instruction. An EEPROM memory location is first automatically erased before new
data is written. If polling (RDY/BSY) is not used, the user must wait at least tWD_EEPROM before issuing the
next byte. (See Table 20-11.) In a chip erased device, no 0xFFs in the data file(s) need to be programmed.
B: The EEPROM array is programmed one page at a time. The Memory page is loaded one byte at a time
by supplying the 2 LSB of the address and data together with the Load EEPROM Memory Page instruction.
The EEPROM Memory Page is stored by loading the Write EEPROM Memory Page Instruction with
the 6 MSB of the address. When using EEPROM page access only byte locations loaded with the Load
EEPROM Memory Page instruction is altered. The remaining locations remain unchanged. If polling
(RDY/BSY) is not used, the used must wait at least tWD_EEPROM before issuing the next page (See Table
20-9). In a chip erased device, no 0xFF in the data file(s) need to be programmed.
6. Any memory location can be verified by using the Read instruction which returns the content at the
selected address at serial output MISO.
7. At the end of the programming session, RESET can be set high to commence normal operation.
8. Power-off sequence (if needed):
Set RESET to “1”.
Turn VCC power off.ATtiny25/45/85 [DATASHEET] 153
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20.5.2 Serial Programming Instruction set
Table 20-12 on page 153 and Figure 20-2 on page 154 describes the Instruction set.
Notes: 1. Not all instructions are applicable for all parts.
Table 20-11. Minimum Wait Delay Before Writing the Next Flash or EEPROM Location
Symbol Minimum Wait Delay
tWD_FLASH 4.5 ms
tWD_EEPROM 4.0 ms
tWD_ERASE 9.0 ms
tWD_FUSE 4.5 ms
Table 20-12. Serial Programming Instruction Set
Instruction/Operation
Instruction Format
Byte 1 Byte 2 Byte 3 Byte4
Programming Enable $AC $53 $00 $00
Chip Erase (Program Memory/EEPROM) $AC $80 $00 $00
Poll RDY/BSY $F0 $00 $00 data byte out
Load Instructions
Load Extended Address byte(1) $4D $00 Extended adr $00
Load Program Memory Page, High byte $48 adr MSB adr LSB high data byte in
Load Program Memory Page, Low byte $40 adr MSB adr LSB low data byte in
Load EEPROM Memory Page (page access) $C1 $00 0000 000aa data byte in
Read Instructions
Read Program Memory, High byte $28 adr MSB adr LSB high data byte out
Read Program Memory, Low byte $20 adr MSB adr LSB low data byte out
Read EEPROM Memory $A0 $00 00aa aaaa data byte out
Read Lock bits $58 $00 $00 data byte out
Read Signature Byte $30 $00 0000 000aa data byte out
Read Fuse bits $50 $00 $00 data byte out
Read Fuse High bits $58 $08 $00 data byte out
Read Extended Fuse Bits $50 $08 $00 data byte out
Read Calibration Byte $38 $00 $00 data byte out
Write Instructions(6)
Write Program Memory Page $4C adr MSB adr LSB $00
Write EEPROM Memory $C0 $00 00aa aaaa data byte in
Write EEPROM Memory Page (page access) $C2 $00 00aa aa00 $00
Write Lock bits $AC $E0 $00 data byte in
Write Fuse bits $AC $A0 $00 data byte in
Write Fuse High bits $AC $A8 $00 data byte in
Write Extended Fuse Bits $AC $A4 $00 data byte inATtiny25/45/85 [DATASHEET] 154
2586Q–AVR–08/2013
2. a = address
3. Bits are programmed ‘0’, unprogrammed ‘1’.
4. To ensure future compatibility, unused Fuses and Lock bits should be unprogrammed (‘1’) .
5. Refer to the correspondig section for Fuse and Lock bits, Calibration and Signature bytes and Page size.
6. Instructions accessing program memory use a word address. This address may be random within the page range.
7. See htt://www.atmel.com/avr for Application Notes regarding programming and programmers.
If the LSB in RDY/BSY data byte out is ‘1’, a programming operation is still pending. Wait until this bit returns ‘0’
before the next instruction is carried out.
Within the same page, the low data byte must be loaded prior to the high data byte.
After data is loaded to the page buffer, program the EEPROM page, see Figure 20-2 on page 154.
Figure 20-2. Serial Programming Instruction example
Byte 1 Byte 2 Byte 3 Byte 4
Adr MSB Adr LSB
Bit 15 B 0
Serial Programming Instruction
Program Memory/
EEPROM Memory
Page 0
Page 1
Page 2
Page N-1
Page Buffer
Write Program Memory Page/
Write EEPROM Memory Page
Load Program Memory Page (High/Low Byte)/
Load EEPROM Memory Page (page access)
Byte 1 Byte 2 Byte 3 Byte 4
Bit 15 B 0
Adr MSB Adr LSB
Page Offset
Page Number
Adr MSB Adr LSBATtiny25/45/85 [DATASHEET] 155
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20.6 High-voltage Serial Programming
This section describes how to program and verify Flash Program memory, EEPROM Data memory, Lock bits and
Fuse bits in the ATtiny25/45/85.
Figure 20-3. High-voltage Serial Programming
The minimum period for the Serial Clock Input (SCI) during High-voltage Serial Programming is 220 ns.
20.7 High-voltage Serial Programming Algorithm
To program and verify the ATtiny25/45/85 in the High-voltage Serial Programming mode, the following sequence is
recommended (See instruction formats in Table 20-16):
Table 20-13. Pin Name Mapping
Signal Name in High-voltage
Serial Programming Mode Pin Name I/O Function
SDI PB0 I Serial Data Input
SII PB1 I Serial Instruction Input
SDO PB2 O Serial Data Output
SCI PB3 I Serial Clock Input (min. 220ns period)
Table 20-14. Pin Values Used to Enter Programming Mode
Pin Symbol Value
SDI Prog_enable[0] 0
SII Prog_enable[1] 0
SDO Prog_enable[2] 0
VCC
GND
SDO
SII
SDI
(RESET)
+4.5 - 5.5V
PB0
PB1
PB2
PB5
+11.5 - 12.5V
SCI PB3ATtiny25/45/85 [DATASHEET] 156
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20.7.1 Enter High-voltage Serial Programming Mode
The following algorithm puts the device in High-voltage Serial Programming mode:
1. Set Prog_enable pins listed in Table 20-14 to “000”, RESET pin and VCC to 0V.
2. Apply 4.5 - 5.5V between VCC and GND. Ensure that VCC reaches at least 1.8V within the next 20 µs.
3. Wait 20 - 60 µs, and apply 11.5 - 12.5V to RESET.
4. Keep the Prog_enable pins unchanged for at least 10 µs after the High-voltage has been applied to
ensure the Prog_enable Signature has been latched.
5. Release the Prog_enable[2] pin to avoid drive contention on the Prog_enable[2]/SDO pin.
6. Wait at least 300 µs before giving any serial instructions on SDI/SII.
7. Exit Programming mode by power the device down or by bringing RESET pin to 0V.
If the rise time of the VCC is unable to fulfill the requirements listed above, the following alternative algorithm can be
used:
1. Set Prog_enable pins listed in Table 20-14 to “000”, RESET pin and VCC to 0V.
2. Apply 4.5 - 5.5V between VCC and GND.
3. Monitor VCC, and as soon as VCC reaches 0.9 - 1.1V, apply 11.5 - 12.5V to RESET.
4. Keep the Prog_enable pins unchanged for at least 10 µs after the High-voltage has been applied to
ensure the Prog_enable Signature has been latched.
5. Release the Prog_enable[2] pin to avoid drive contention on the Prog_enable[2]/SDO pin.
6. Wait until VCC actually reaches 4.5 - 5.5V before giving any serial instructions on SDI/SII.
7. Exit Programming mode by power the device down or by bringing RESET pin to 0V.
20.7.2 Considerations for Efficient Programming
The loaded command and address are retained in the device during programming. For efficient programming, the
following should be considered.
• The command needs only be loaded once when writing or reading multiple memory locations.
• Skip writing the data value 0xFF that is the contents of the entire EEPROM (unless the EESAVE Fuse is
programmed) and Flash after a Chip Erase.
• Address High byte needs only be loaded before programming or reading a new 256 word window in Flash or
256 byte EEPROM. This consideration also applies to Signature bytes reading.
20.7.3 Chip Erase
The Chip Erase will erase the Flash and EEPROM(1) memories plus Lock bits. The Lock bits are not reset until the
Program memory has been completely erased. The Fuse bits are not changed. A Chip Erase must be performed
before the Flash and/or EEPROM are re-programmed.
Note: 1. The EEPROM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
Table 20-15. High-voltage Reset Characteristics
Supply Voltage RESET Pin High-voltage Threshold
Minimum High-voltage Period for
Latching Prog_enable
VCC VHVRST tHVRST
4.5V 11.5V 100 ns
5.5V 11.5V 100 nsATtiny25/45/85 [DATASHEET] 157
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1. Load command “Chip Erase” (see Table 20-16).
2. Wait after Instr. 3 until SDO goes high for the “Chip Erase” cycle to finish.
3. Load Command “No Operation”.
20.7.4 Programming the Flash
The Flash is organized in pages, see Table 20-12 on page 153. When programming the Flash, the program data is
latched into a page buffer. This allows one page of program data to be programmed simultaneously. The following
procedure describes how to program the entire Flash memory:
1. Load Command “Write Flash” (see Table 20-16).
2. Load Flash Page Buffer.
3. Load Flash High Address and Program Page. Wait after Instr. 3 until SDO goes high for the “Page Programming”
cycle to finish.
4. Repeat 2 through 3 until the entire Flash is programmed or until all data has been programmed.
5. End Page Programming by Loading Command “No Operation”.
When writing or reading serial data to the ATtiny25/45/85, data is clocked on the rising edge of the serial clock, see
Figure 20-5, Figure 21-6 and Table 21-12 for details.
Figure 20-4. Addressing the Flash which is Organized in Pages
Figure 20-5. High-voltage Serial Programming Waveforms
PROGRAM MEMORY
WORD ADDRESS
WITHIN A PAGE
PAGE ADDRESS
WITHIN THE FLASH
INSTRUCTION WORD
PAGE PCWORD[PAGEMSB:0]:
00
01
02
PAGEEND
PAGE
PCPAGE PCWORD
PCMSB PAGEMSB
PROGRAM
COUNTER
MSB
MSB
MSB LSB
LSB
LSB
0 1 2 3 4 5 6 7 8 9 10
SDI
PB0
SII
PB1
SDO
PB2
SCI
PB3ATtiny25/45/85 [DATASHEET] 158
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20.7.5 Programming the EEPROM
The EEPROM is organized in pages, see Table 21-11 on page 170. When programming the EEPROM, the data is
latched into a page buffer. This allows one page of data to be programmed simultaneously. The programming algorithm
for the EEPROM Data memory is as follows (refer to Table 20-16):
1. Load Command “Write EEPROM”.
2. Load EEPROM Page Buffer.
3. Program EEPROM Page. Wait after Instr. 2 until SDO goes high for the “Page Programming” cycle to
finish.
4. Repeat 2 through 3 until the entire EEPROM is programmed or until all data has been programmed.
5. End Page Programming by Loading Command “No Operation”.
20.7.6 Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to Table 20-16):
1. Load Command "Read Flash".
2. Read Flash Low and High Bytes. The contents at the selected address are available at serial output SDO.
20.7.7 Reading the EEPROM
The algorithm for reading the EEPROM memory is as follows (refer to Table 20-16):
1. Load Command “Read EEPROM”.
2. Read EEPROM Byte. The contents at the selected address are available at serial output SDO.
20.7.8 Programming and Reading the Fuse and Lock Bits
The algorithms for programming and reading the Fuse Low/High bits and Lock bits are shown in Table 20-16.
20.7.9 Reading the Signature Bytes and Calibration Byte
The algorithms for reading the Signature bytes and Calibration byte are shown in Table 20-16.
20.7.10 Power-off sequence
Set SCI to “0”. Set RESET to “1”. Turn VCC power off.
Table 20-16. High-voltage Serial Programming Instruction Set for ATtiny25/45/85
Instruction
Instruction Format
Instr.1/5 Instr.2/6 Instr.3 Instr.4 Operation Remarks
Chip Erase
SDI
SII
SDO
0_1000_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Wait after Instr.3 until SDO
goes high for the Chip Erase
cycle to finish.
Load “Write
Flash”
Command
SDI
SII
SDO
0_0001_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
Enter Flash Programming
code.
Load Flash
Page Buffer
SDI
SII
SDO
0_bbbb_bbbb _00
0_0000_1100_00
x_xxxx_xxxx_xx
0_eeee_eeee_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_dddd_dddd_00
0_0011_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1101_00
x_xxxx_xxxx_xx
Repeat after Instr. 1 - 5 until
the entire page buffer is filled
or until all data within the
page is filled.(2)
SDI
SII
SDO
0_0000_0000_00
0_0111_1100_00
x_xxxx_xxxx_xx
Instr 5.ATtiny25/45/85 [DATASHEET] 159
2586Q–AVR–08/2013
Load Flash
High Address
and Program
Page
SDI
SII
SDO
0_0000_000a_00
0_0001_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Wait after Instr 3 until SDO
goes high. Repeat Instr. 2 - 3
for each loaded Flash Page
until the entire Flash or all
data is programmed. Repeat
Instr. 1 for a new 256 byte
page.(2)
Load “Read
Flash”
Command
SDI
SII
SDO
0_0000_0010_00
0_0100_1100_00
x_xxxx_xxxx_xx
Enter Flash Read mode.
Read Flash
Low and High
Bytes
SDI
SII
SDO
0_bbbb_bbbb_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_0000_000a_00
0_0001_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
q_qqqq_qqqx_xx
Repeat Instr. 1, 3 - 6 for each
new address. Repeat Instr. 2
for a new 256 byte page.
SDI
SII
SDO
0_0000_0000_00
0_0111_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1100_00
p_pppp_pppx_xx
Instr 5 - 6.
Load “Write
EEPROM”
Command
SDI
SII
SDO
0_0001_0001_00
0_0100_1100_00
x_xxxx_xxxx_xx
Enter EEPROM Programming
mode.
Load
EEPROM
Page Buffer
SDI
SII
SDO
0_00bb_bbbb_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_aaaa_aaaa_00
0_0001_1100_00
x_xxxx_xxxx_xx
0_eeee_eeee_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1101_00
x_xxxx_xxxx_xx
Repeat Instr. 1 - 5 until the
entire page buffer is filled or
until all data within the page is
filled.(3)
SDI
SII
SDO
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Instr. 5
Program
EEPROM
Page
SDI
SII
SDO
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Wait after Instr. 2 until SDO
goes high. Repeat Instr. 1 - 2
for each loaded EEPROM
page until the entire
EEPROM or all data is
programmed.
Write
EEPROM
Byte
SDI
SII
SDO
0_bbbb_bbbb_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_aaaa_aaaa_00
0_0001_1100_00
x_xxxx_xxxx_xx
0_eeee_eeee_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1101_00
x_xxxx_xxxx_xx
Repeat Instr. 1 - 6 for each
new address. Wait after Instr.
6 until SDO goes high.(4)
SDI
SII
SDO
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Instr. 6
Load “Read
EEPROM”
Command
SDI
SII
SDO
0_0000_0011_00
0_0100_1100_00
x_xxxx_xxxx_xx
Enter EEPROM Read mode.
Read
EEPROM
Byte
SDI
SII
SDO
0_bbbb_bbbb_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_aaaa_aaaa_00
0_0001_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
q_qqqq_qqq0_00
Repeat Instr. 1, 3 - 4 for each
new address. Repeat Instr. 2
for a new 256 byte page.
Write Fuse
Low Bits
SDI
SII
SDO
0_0100_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_A987_6543_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Wait after Instr. 4 until SDO
goes high. Write A - 3 = “0” to
program the Fuse bit.
Table 20-16. High-voltage Serial Programming Instruction Set for ATtiny25/45/85 (Continued)
Instruction
Instruction Format
Instr.1/5 Instr.2/6 Instr.3 Instr.4 Operation RemarksATtiny25/45/85 [DATASHEET] 160
2586Q–AVR–08/2013
Notes: 1. a = address high bits, b = address low bits, d = data in high bits, e = data in low bits, p = data out high bits, q = data out low
bits, x = don’t care, 1 = Lock Bit1, 2 = Lock Bit2, 3 = CKSEL0 Fuse, 4 = CKSEL1 Fuse, 5 = CKSEL2 Fuse, 6 = CKSEL3
Fuse, 7 = SUT0 Fuse, 8 = SUT1 Fuse, 9 = CKOUT Fuse, A = CKDIV8 Fuse, B = BODLEVEL0 Fuse, C = BODLEVEL1
Fuse, D = BODLEVEL2 Fuse, E = EESAVE Fuse, F = WDTON Fuse, G = SPIEN Fuse, H = DWEN Fuse, I = RSTDISBL
Fuse, J = SELFPRGEN Fuse
2. For page sizes less than 256 words, parts of the address (bbbb_bbbb) will be parts of the page address.
3. For page sizes less than 256 bytes, parts of the address (bbbb_bbbb) will be parts of the page address.
4. The EEPROM is written page-wise. But only the bytes that are loaded into the page are actually written to the EEPROM.
Page-wise EEPROM access is more efficient when multiple bytes are to be written to the same page. Note that auto-erase
of EEPROM is not available in High-voltage Serial Programming, only in SPI Programming.
Write Fuse
High Bits
SDI
SII
SDO
0_0100_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_IHGF_EDCB_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1100_00
x_xxxx_xxxx_xx
Wait after Instr. 4 until SDO
goes high. Write I - B = “0” to
program the Fuse bit.
Write Fuse
Extended Bits
SDI
SII
SDO
0_0100_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_000J_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_0110_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1110_00
x_xxxx_xxxx_xx
Wait after Instr. 4 until SDO
goes high. Write J = “0” to
program the Fuse bit.
Write Lock
Bits
SDI
SII
SDO
0_0010_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0021_00
0_0010_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_0100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
x_xxxx_xxxx_xx
Wait after Instr. 4 until SDO
goes high. Write 2 - 1 = “0” to
program the Lock bit.
Read Fuse
Low Bits
SDI
SII
SDO
0_0000_0100_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
A_9876_543x_xx
Reading A - 3 = “0” means
the Fuse bit is programmed.
Read Fuse
High Bits
SDI
SII
SDO
0_0000_0100_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1010_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1110_00
I_HGFE_DCBx_xx
Reading I - B = “0” means the
Fuse bit is programmed.
Read Fuse
Extended Bits
SDI
SII
SDO
0_0000_0100_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1010_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1110_00
x_xxxx_xxJx_xx
Reading J = “0” means the
Fuse bit is programmed.
Read Lock
Bits
SDI
SII
SDO
0_0000_0100_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1100_00
x_xxxx_x21x_xx
Reading 2, 1 = “0” means the
Lock bit is programmed.
Read
Signature
Bytes
SDI
SII
SDO
0_0000_1000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_00bb_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0110_1100_00
q_qqqq_qqqx_xx
Repeats Instr 2 4 for each
signature byte address.
Read
Calibration
Byte
SDI
SII
SDO
0_0000_1000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0000_1100_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1000_00
x_xxxx_xxxx_xx
0_0000_0000_00
0_0111_1100_00
p_pppp_pppx_xx
Load “No
Operation”
Command
SDI
SII
SDO
0_0000_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
Table 20-16. High-voltage Serial Programming Instruction Set for ATtiny25/45/85 (Continued)
Instruction
Instruction Format
Instr.1/5 Instr.2/6 Instr.3 Instr.4 Operation RemarksATtiny25/45/85 [DATASHEET] 161
2586Q–AVR–08/2013
21. Electrical Characteristics
21.1 Absolute Maximum Ratings*
21.2 DC Characteristics
Operating Temperature.................................. -55C to +125C *NOTICE: Stresses beyond 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 these or
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect
device reliability.
Storage Temperature ..................................... -65°C to +150°C
Voltage on any Pin except RESET
with respect to Ground ................................-0.5V to VCC+0.5V
Voltage on RESET with respect to Ground......-0.5V to +13.0V
Maximum Operating Voltage ............................................ 6.0V
DC Current per I/O Pin ............................................... 40.0 mA
DC Current VCC and GND Pins................................ 200.0 mA
Table 21-1. DC Characteristics. TA = -40C to +85C
Symbol Parameter Condition Min. Typ.(1) Max. Units
VIL
Input Low-voltage, except
XTAL1 and RESET pin
VCC = 1.8V - 2.4V
VCC = 2.4V - 5.5V
-0.5
-0.5
0.2VCC(3)
0.3VCC(3)
V
V
VIH
Input High-voltage, except
XTAL1 and RESET pin
VCC = 1.8V - 2.4V
VCC = 2.4V - 5.5V
0.7VCC(2)
0.6VCC(2)
VCC +0.5
VCC +0.5
V
V
VIL1
Input Low-voltage, XTAL1 pin,
External Clock Selected VCC = 1.8V - 5.5V -0.5 0.1VCC(3) V
VIH1
Input High-voltage, XTAL1 pin,
External Clock Selected
VCC = 1.8V - 2.4V
VCC = 2.4V - 5.5V
0.8VCC(2)
0.7VCC(2)
VCC +0.5
VCC +0.5
V
V
VIL2
Input Low-voltage,
RESET pin VCC = 1.8V - 5.5V -0.5 0.2VCC(3) V
V
VIH2
Input High-voltage,
RESET pin VCC = 1.8V - 5.5V 0.9VCC(2) VCC +0.5 V
VIL3
Input Low-voltage,
RESET pin as I/O
VCC = 1.8V - 2.4V
VCC = 2.4V - 5.5V
-0.5
-0.5
0.2VCC(3)
0.3VCC(3)
V
V
VIH3
Input High-voltage,
RESET pin as I/O
VCC = 1.8V - 2.4V
VCC = 2.4V - 5.5V
0.7VCC(2)
0.6VCC(2)
VCC +0.5
VCC +0.5
V
V
VOL
Output Low-voltage,(4)
Port B (except RESET) (6)
IOL = 10 mA, VCC = 5V
IOL = 5 mA, VCC = 3V
0.6
0.5
V
V
VOH
Output High-voltage, (5)
Port B (except RESET) (6)
IOH = -10 mA, VCC = 5V
IOH = -5 mA, VCC = 3V
4.3
2.5
V
V
IIL
Input Leakage
Current I/O Pin
VCC = 5.5V, pin low
(absolute value) < 0.05 1 µA
IIH
Input Leakage
Current I/O Pin
VCC = 5.5V, pin high
(absolute value) < 0.05 1 µA
RRST Reset Pull-up Resistor VCC = 5.5V, input low 30 60 kATtiny25/45/85 [DATASHEET] 162
2586Q–AVR–08/2013
Notes: 1. Typical values at 25C.
2. “Min” means the lowest value where the pin is guaranteed to be read as high.
3. “Max” means the highest value where the pin is guaranteed to be read as low.
4. Although each I/O port can sink more than the test conditions (10 mA at VCC = 5V, 5 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOL, for all ports, should not exceed 60 mA.
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test condition.
5. Although each I/O port can source more than the test conditions (10 mA at VCC = 5V, 5 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOH, for all ports, should not exceed 60 mA.
If IOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current
greater than the listed test condition.
6. The RESET pin must tolerate high voltages when entering and operating in programming modes and, as a consequence,
has a weak drive strength as compared to regular I/O pins. See Figure 22-23, Figure 22-24, Figure 22-25, and Figure 22-26
(starting on page 184).
7. Values are with external clock using methods described in “Minimizing Power Consumption” on page 36. Power Reduction
is enabled (PRR = 0xFF) and there is no I/O drive.
8. Brown-Out Detection (BOD) disabled.
Rpu I/O Pin Pull-up Resistor VCC = 5.5V, input low 20 50 k
ICC
Power Supply Current (7)
Active 1 MHz, VCC = 2V 0.3 0.55 mA
Active 4 MHz, VCC = 3V 1.5 2.5 mA
Active 8 MHz, VCC = 5V 5 8 mA
Idle 1 MHz, VCC = 2V 0.1 0.2 mA
Idle 4 MHz, VCC = 3V 0.35 0.6 mA
Idle 8 MHz, VCC = 5V 1.2 2 mA
Power-down mode (8) WDT enabled, VCC = 3V 10 µA
WDT disabled, VCC = 3V 2 µA
Table 21-1. DC Characteristics. TA = -40C to +85C (Continued)
Symbol Parameter Condition Min. Typ.(1) Max. UnitsATtiny25/45/85 [DATASHEET] 163
2586Q–AVR–08/2013
21.3 Speed
Figure 21-1. Maximum Frequency vs. VCC
Figure 21-2. Maximum Frequency vs. VCC
10 MHz
4 MHz
1.8V 2.7V 5.5V
Safe Operating Area
20 MHz
10 MHz
2.7V 4.5V 5.5V
Safe Operating AreaATtiny25/45/85 [DATASHEET] 164
2586Q–AVR–08/2013
21.4 Clock Characteristics
21.4.1 Calibrated Internal RC Oscillator Accuracy
It is possible to manually calibrate the internal oscillator to be more accurate than default factory calibration. Please
note that the oscillator frequency depends on temperature and voltage. Voltage and temperature characteristics
can be found in Figure 22-40 on page 193 and Figure 22-41 on page 193.
Notes: 1. Accuracy of oscillator frequency at calibration point (fixed temperature and fixed voltage).
2. ATtiny25/V, only: 6.4 MHz in ATtiny15 Compatibility Mode.
3. Voltage range for ATtiny25V/45V/85V.
4. Voltage range for ATtiny25/45/85.
21.4.2 External Clock Drive
Figure 21-3. External Clock Drive Waveforms
Table 21-2. Calibration Accuracy of Internal RC Oscillator
Calibration
Method Target Frequency VCC Temperature
Accuracy at given Voltage
& Temperature (1)
Factory
Calibration 8.0 MHz (2) 3V 25C ±10%
User
Calibration
Fixed frequency within:
6 – 8 MHz
Fixed voltage within:
1.8V - 5.5V (3)
2.7V - 5.5V (4)
Fixed temperature
within:
-40C to +85C
±1%
VIL1
VIH1
Table 21-3. External Clock Drive Characteristics
Symbol Parameter
VCC = 1.8 - 5.5V VCC = 2.7 - 5.5V VCC = 4.5 - 5.5V
Min. Max. Min. Max. Min. Max. Units
1/tCLCL Clock Frequency 0 4 0 10 0 20 MHz
tCLCL Clock Period 250 100 50 ns
tCHCX High Time 100 40 20 ns
tCLCX Low Time 100 40 20 ns
tCLCH Rise Time 2.0 1.6 0.5 µs
tCHCL Fall Time 2.0 1.6 0.5 µs
t
CLCL Change in period from one clock cycle to the next 2 2 2 %ATtiny25/45/85 [DATASHEET] 165
2586Q–AVR–08/2013
21.5 System and Reset Characteristics
Note: 1. Values are guidelines only.
Two versions of power-on reset have been implemented, as follows.
21.5.1 Standard Power-On Reset
This implementation of power-on reset existed in early versions of ATtiny25/45/85. The table below describes the
characteristics of this power-on reset and it is valid for the following devices, only:
• ATtiny25, revision D, and older
• ATtiny45, revision F, and older
• ATtiny85, revision B, and newer
Note: Revisions are marked on the package (packages 8P3 and 8S2: bottom, package 20M1: top)
Note: 1. Values are guidelines, only
2. Threshold where device is released from reset when voltage is rising
3. The power-on reset will not work unless the supply voltage has been below VPOA
21.5.2 Enhanced Power-On Reset
This implementation of power-on reset exists in newer versions of ATtiny25/45/85. The table below describes the
characteristics of this power-on reset and it is valid for the following devices, only:
• ATtiny25, revision E, and newer
Table 21-4. Reset, Brown-out and Internal Voltage Characteristics
Symbol Parameter Condition Min(1) Typ(1) Max(1) Units
VRST RESET Pin Threshold Voltage VCC = 3V 0.2 VCC 0.9 VCC V
tRST
Minimum pulse width on
RESET Pin VCC = 3V 2.5 µs
VHYST Brown-out Detector Hysteresis 50 mV
tBOD
Min Pulse Width on
Brown-out Reset 2 µs
VBG
Bandgap reference
voltage
VCC = 5.5V
TA = 25°C 1.0 1.1 1.2 V
tBG
Bandgap reference
start-up time
VCC = 2.7V
TA = 25°C 40 70 µs
IBG
Bandgap reference
current consumption
VCC = 2.7V
TA = 25°C 15 µA
Table 21-5. Characteristics of Standard Power-On Reset. TA = -40 to +85C
Symbol Parameter Min(1) Typ(1) Max(1) Units
VPOR Release threshold of power-on reset (2) 0.7 1.0 1.4 V
VPOA Activation threshold of power-on reset (3) 0.05 0.9 1.3 V
SRON Power-on slope rate 0.01 4.5 V/msATtiny25/45/85 [DATASHEET] 166
2586Q–AVR–08/2013
• ATtiny45, revision G, and newer
• ATtiny85, revision C, and newer
Note: 1. Values are guidelines, only
2. Threshold where device is released from reset when voltage is rising
3. The Power-on Reset will not work unless the supply voltage has been below VPOT (falling)
21.6 Brown-Out Detection
Note: 1. VBOT may be below nominal minimum operating voltage for some devices. For devices where this is the case, the
device is tested down to VCC = VBOT during the production test. This guarantees that a Brown-out Reset will occur
before VCC drops to a voltage where correct operation of the microcontroller is no longer guaranteed.
Table 21-6. Characteristics of Enhanced Power-On Reset. TA = -40C to +85C
Symbol Parameter Min(1) Typ(1) Max(1) Units
VPOR Release threshold of power-on reset (2) 1.1 1.4 1.6 V
VPOA Activation threshold of power-on reset (3) 0.6 1.3 1.6 V
SRON Power-On Slope Rate 0.01 V/ms
Table 21-7. BODLEVEL Fuse Coding. TA = -40C to +85C
BODLEVEL[2:0] Fuses Min(1) Typ(1) Max(1) Units
111 BOD Disabled
110 1.7 1.8 2.0
101 2.5 2.7 2.9 V
100 4.1 4.3 4.5
0XX ReservedATtiny25/45/85 [DATASHEET] 167
2586Q–AVR–08/2013
21.7 ADC Characteristics
Note: 1. Values are guidelines only.
Table 21-8. ADC Characteristics, Single Ended Channels. TA = -40C to +85C
Symbol Parameter Condition Min Typ Max Units
Resolution 10 Bits
Absolute accuracy
(Including INL, DNL, and
Quantization, Gain and
Offset errors)
VREF = 4V, VCC = 4V,
ADC clock = 200 kHz 2 LSB
VREF = 4V, VCC = 4V,
ADC clock = 1 MHz 3 LSB
VREF = 4V, VCC = 4V,
ADC clock = 200 kHz
Noise Reduction Mode
1.5 LSB
VREF = 4V, VCC = 4V,
ADC clock = 1 MHz
Noise Reduction Mode
2.5 LSB
Integral Non-linearity (INL)
(Accuracy after offset and gain
calibration)
VREF = 4V, VCC = 4V,
ADC clock = 200 kHz 1 LSB
Differential Non-linearity (DNL) VREF = 4V, VCC = 4V,
ADC clock = 200 kHz 0.5 LSB
Gain Error VREF = 4V, VCC = 4V,
ADC clock = 200 kHz 2.5 LSB
Offset Error VREF = 4V, VCC = 4V,
ADC clock = 200 kHz 1.5 LSB
Conversion Time Free Running Conversion 14 280 µs
Clock Frequency 50 1000 kHz
VIN Input Voltage GND VREF V
Input Bandwidth 38.4 kHz
AREF External Reference Voltage 2.0 VCC V
VINT
Internal Voltage Reference 1.0 1.1 1.2 V
Internal 2.56V Reference (1) VCC > 3.0V 2.3 2.56 2.8 V
RREF 32 k
RAIN Analog Input Resistance 100 M
ADC Output 0 1023 LSBATtiny25/45/85 [DATASHEET] 168
2586Q–AVR–08/2013
Note: 1. Values are guidelines only.
Table 21-9. ADC Characteristics, Differential Channels (Unipolar Mode). TA = -40C to +85C
Symbol Parameter Condition Min Typ Max Units
Resolution
Gain = 1x 10 Bits
Gain = 20x 10 Bits
Absolute accuracy
(Including INL, DNL, and
Quantization, Gain and Offset
Errors)
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
10.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
20.0 LSB
Integral Non-Linearity (INL)
(Accuracy after Offset and
Gain Calibration)
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
4.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
10.0 LSB
Gain Error
Gain = 1x 10.0 LSB
Gain = 20x 15.0 LSB
Offset Error
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
3.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
4.0 LSB
Conversion Time Free Running Conversion 70 280 µs
Clock Frequency 50 200 kHz
VIN Input Voltage GND VCC V
VDIFF Input Differential Voltage VREF/Gain V
Input Bandwidth 4 kHz
AREF External Reference Voltage 2.0 VCC - 1.0 V
VINT
Internal Voltage Reference 1.0 1.1 1.2 V
Internal 2.56V Reference (1) VCC > 3.0V 2.3 2.56 2.8 V
RREF Reference Input Resistance 32 k
RAIN Analog Input Resistance 100 M
ADC Conversion Output 0 1023 LSBATtiny25/45/85 [DATASHEET] 169
2586Q–AVR–08/2013
Note: 1. Values are guidelines only.
Table 21-10. ADC Characteristics, Differential Channels (Bipolar Mode). TA = -40C to +85C
Symbol Parameter Condition Min Typ Max Units
Resolution
Gain = 1x 10 Bits
Gain = 20x 10 Bits
Absolute accuracy
(Including INL, DNL, and
Quantization, Gain and Offset
Errors)
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
8.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
8.0 LSB
Integral Non-Linearity (INL)
(Accuracy after Offset and
Gain Calibration)
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
4.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
5.0 LSB
Gain Error
Gain = 1x 4.0 LSB
Gain = 20x 5.0 LSB
Offset Error
Gain = 1x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
3.0 LSB
Gain = 20x
VREF = 4V, VCC = 5V
ADC clock = 50 - 200 kHz
4.0 LSB
Conversion Time Free Running Conversion 70 280 µs
Clock Frequency 50 200 kHz
VIN Input Voltage GND VCC V
VDIFF Input Differential Voltage VREF/Gain V
Input Bandwidth 4 kHz
AREF External Reference Voltage 2.0 VCC - 1.0 V
VINT
Internal Voltage Reference 1.0 1.1 1.2 V
Internal 2.56V Reference (1) VCC > 3.0V 2.3 2.56 2.8 V
RREF Reference Input Resistance 32 k
RAIN Analog Input Resistance 100 M
ADC Conversion Output -512 511 LSBATtiny25/45/85 [DATASHEET] 170
2586Q–AVR–08/2013
21.8 Serial Programming Characteristics
Figure 21-4. Serial Programming Waveforms
Figure 21-5. Serial Programming Timing
Note: 1. 2 tCLCL for fck < 12 MHz, 3 tCLCL for fck >= 12 MHz
Table 21-11. Serial Programming Characteristics, TA = -40C to +85C, VCC = 1.8 - 5.5V (Unless Otherwise
Noted)
Symbol Parameter Min Typ Max Units
1/tCLCL Oscillator Frequency (VCC = 1.8 - 5.5V) 0 4 MHz
tCLCL Oscillator Period (VCC = 1.8 - 5.5V) 250 ns
1/tCLCL Oscillator Frequency (VCC = 2.7 - 5.5V) 0 10 MHz
t
CLCL Oscillator Period (VCC = 2.7 - 5.5V) 100 ns
1/tCLCL Oscillator Frequency (VCC = 4.5V - 5.5V) 0 20 MHz
t
CLCL Oscillator Period (VCC = 4.5V - 5.5V) 50 ns
t
SHSL SCK Pulse Width High 2 tCLCL* ns
t
SLSH SCK Pulse Width Low 2 tCLCL* ns
t
OVSH MOSI Setup to SCK High tCLCL ns
t
SHOX MOSI Hold after SCK High 2 tCLCL ns
tSLIV SCK Low to MISO Valid 100 ns
MSB
MSB
LSB
LSB
SERIAL CLOCK INPUT
(SCK)
SERIAL DATA INPUT
(MOSI)
(MISO)
SAMPLE
SERIAL DATA OUTPUT
MOSI
MISO
SCK
t
OVSH
t
SHSL
t t
SHOX SLSH
t
SLIVATtiny25/45/85 [DATASHEET] 171
2586Q–AVR–08/2013
21.9 High-voltage Serial Programming Characteristics
Figure 21-6. High-voltage Serial Programming Timing
Table 21-12. High-voltage Serial Programming Characteristics TA = 25C ± 10%, VCC = 5.0V ± 10% (Unless otherwise
noted)
Symbol Parameter Min Typ Max Units
tSHSL SCI (PB3) Pulse Width High 125 ns
tSLSH SCI (PB3) Pulse Width Low 125 ns
tIVSH SDI (PB0), SII (PB1) Valid to SCI (PB3) High 50 ns
t
SHIX SDI (PB0), SII (PB1) Hold after SCI (PB3) High 50 ns
t
SHOV SCI (PB3) High to SDO (PB2) Valid 16 ns
tWLWH_PFB Wait after Instr. 3 for Write Fuse Bits 2.5 ms
SDI (PB0), SII (PB1)
SDO (PB2)
SCI (PB3)
t
IVSH
t
SHSL
t t
SHIX SLSH
t
SHOVATtiny25/45/85 [DATASHEET] 172
2586Q–AVR–08/2013
22. Typical Characteristics
The data contained in this section is largely based on simulations and characterization of similar devices in the
same process and design methods. Thus, the data should be treated as indications of how the part will behave.
The following charts show typical behavior. These figures are not tested during manufacturing. All current consumption
measurements are performed with all I/O pins configured as inputs and with internal pull-ups enabled. A
sine wave generator with rail-to-rail output is used as clock source.
The power consumption in Power-down mode is independent of clock selection.
The current consumption is a function of several factors such as: operating voltage, operating frequency, loading of
I/O pins, switching rate of I/O pins, code executed and ambient temperature. The dominating factors are operating
voltage and frequency.
The current drawn from capacitive loaded pins may be estimated (for one pin) as CL*VCC*f where CL = load capacitance,
VCC = operating voltage and f = average switching frequency of I/O pin.
The parts are characterized at frequencies higher than test limits. Parts are not guaranteed to function properly at
frequencies higher than the ordering code indicates.
The difference between current consumption in Power-down mode with Watchdog Timer enabled and Power-down
mode with Watchdog Timer disabled represents the differential current drawn by the Watchdog Timer.
22.1 Active Supply Current
Figure 22-1. Active Supply Current vs. Low frequency (0.1 - 1.0 MHz)
ACTIVE SUPPLY CURRENT vs. LOW FREQUENCY
0.1 -1.0 MHz
5.5 V
5.0 V
4.5 V
4.0 V
3.3 V
2.7 V
1.8 V
0
0,2
0,4
0,6
0,8
1
1,2
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Frequency (MHz)
ICC (mA)ATtiny25/45/85 [DATASHEET] 173
2586Q–AVR–08/2013
Figure 22-2. Active Supply Current vs. Frequency (1 - 20 MHz)
Figure 22-3. Active Supply Current vs. VCC (Internal RC oscillator, 8 MHz)
ACTIVE SUPPLY CURRENT vs. FREQUENCY
1 - 20 MHz
5.5 V
5.0 V
4.5 V
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16 18 20
Frequency (MHz)
ICC (mA)
1.8V
2.7V
3.3V
4.0V
ACTIVE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 8 MHz
85 ˚C
25 ˚C
-40 ˚C
0
1
2
3
4
5
6
7
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)ATtiny25/45/85 [DATASHEET] 174
2586Q–AVR–08/2013
Figure 22-4. Active Supply Current vs. VCC (Internal RC Oscillator, 1 MHz)
Figure 22-5. Active Supply Current vs. VCC (Internal RC Oscillator, 128 kHz)
ACTIVE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 1 MHz
85 ˚C
25 ˚C
-40 ˚C
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)
ACTIVE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 128 KHz
85 ˚C
25 ˚C
-40 ˚C
0
0,05
0,1
0,15
0,2
0,25
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)ATtiny25/45/85 [DATASHEET] 175
2586Q–AVR–08/2013
22.2 Idle Supply Current
Figure 22-6. Idle Supply Current vs. low Frequency (0.1 - 1.0 MHz)
Figure 22-7. Idle Supply Current vs. Frequency (1 - 20 MHz)
IDLE SUPPLY CURRENT vs. LOW FREQUENCY
0.1 - 1.0 MHz
5.5 V
5.0 V
4.5 V
4.0 V
3.3 V
2.7 V
1.8 V
0
0,05
0,1
0,15
0,2
0,25
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Frequency (MHz)
ICC (mA)
IDLE SUPPLY CURRENT vs. FREQUENCY
1 - 20 MHz
5.5 V
5.0 V
4.5 V
0
0,5
1
1,5
2
2,5
3
3,5
4
0 2 4 6 8 10 12 14 16 18 20
Frequency (MHz)
ICC (mA)
1.8V
2.7V
3.3V
4.0VATtiny25/45/85 [DATASHEET] 176
2586Q–AVR–08/2013
Figure 22-8. Idle Supply Current vs. VCC (Internal RC Oscillator, 8 MHz)I
Figure 22-9. Idle Supply Current vs. VCC (Internal RC Oscilllator, 1 MHz)
IDLE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 8 MHz
85 ˚C
25 ˚C
-40 ˚C
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)
IDLE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 1 MHz
85 ˚C
25 ˚C
-40 ˚C
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
0,5
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)ATtiny25/45/85 [DATASHEET] 177
2586Q–AVR–08/2013
Figure 22-10. Idle Supply Current vs. VCC (Internal RC Oscillator, 128 kHz)
22.3 Supply Current of I/O modules
The tables and formulas below can be used to calculate the additional current consumption for the different I/O
modules in Active and Idle mode. The enabling or disabling of the I/O modules are controlled by the Power Reduction
Register. See “PRR – Power Reduction Register” on page 38 for details.
It is possible to calculate the typical current consumption based on the numbers from Table 22-2 for other VCC and
frequency settings that listed in Table 22-1.
IDLE SUPPLY CURRENT vs. VCC
INTERNAL RC OSCILLATOR, 128 kHz
85 ˚C
25 ˚C
-40 ˚C
0
0,01
0,02
0,03
0,04
0,05
0,06
0,07
0,08
0,09
0,1
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)
Table 22-1. Additional Current Consumption for the different I/O modules (absolute values)
PRR bit Typical numbers
VCC = 2V, f = 1 MHz VCC = 3V, f = 4 MHz VCC = 5V, f = 8 MHz
PRTIM1 45 uA 300 uA 1100 uA
PRTIM0 5 uA 30 uA 110 uA
PRUSI 5 uA 25 uA 100 uA
PRADC 15 uA 85 uA 340 uA
Table 22-2. Additional Current Consumption (percentage) in Active and Idle mode
PRR bit
Additional Current consumption
compared to Active with external clock
(see Figure 22-1 and Figure 22-2)
Additional Current consumption
compared to Idle with external clock
(see Figure 22-6 and Figure 22-7)
PRTIM1 20 % 80 %
PRTIM0 2 % 10 %
PRUSI 2 % 10 %
PRADC 5 % 25 %ATtiny25/45/85 [DATASHEET] 178
2586Q–AVR–08/2013
22.3.1 Example
Calculate the expected current consumption in idle mode with USI, TIMER0, and ADC enabled at VCC = 2.0V and f
= 1 MHz. From Table 22-2 on page 177, third column, we see that we need to add 10% for the USI, 25% for the
ADC, and 10% for the TIMER0 module. Reading from Figure 22-9, we find that the idle current consumption is
~0,18 mA at VCC = 2.0V and f = 1 MHz. The total current consumption in idle mode with USI, TIMER0, and ADC
enabled, gives:
22.4 Power-down Supply Current
Figure 22-11. Power-down Supply Current vs. VCC (Watchdog Timer Disabled)
ICC = 0 18 , mA 1 01 ++ + , 0 25 , 0 1, 0 261 , mA
POWER-DOWN SUPPLY CURRENT vs. VCC
WATCHDOG TIMER DISABLED
85 ˚C
25 ˚C
-40 ˚C
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.5 2 2.5 3 3.5 4 4.5 5 5.5
VCC (V)
ICC (uA)ATtiny25/45/85 [DATASHEET] 179
2586Q–AVR–08/2013
Figure 22-12. Power-down Supply Current vs. VCC (Watchdog Timer Enabled)
22.5 Pin Pull-up
Figure 22-13. I/O Pin Pull-up Resistor Current vs. Input Voltage (VCC = 1.8V)
POWER-DOWN SUPPLY CURRENT vs. VCC
WATCHDOG TIMER ENABLED
85 ˚C
25 ˚C
-40 ˚C
0
2
4
6
8
10
12
14
1.5 2 2.5 3 3.5 4 4.5 5 5.5
VCC (V)
ICC (uA)
I/O PIN PULL-UP RESISTOR CURRENT vs. INPUT VOLTAGE
VCC = 1.8V
85 ˚C
25 ˚C
0 -40 ˚C
10
20
30
40
50
60
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2
VOP (V)
IOP (uA)ATtiny25/45/85 [DATASHEET] 180
2586Q–AVR–08/2013
Figure 22-14. I/O Pin Pull-up Resistor Current vs. Input Voltage (VCC = 2.7V)
Figure 22-15. I/O Pin Pull-up Resistor Current vs. Input Voltage (VCC = 5V)
I/O PIN PULL-UP RESISTOR CURRENT vs. INPUT VOLTAGE
VCC = 2.7V
85 ˚C
25 ˚C
-40 ˚C
0
10
20
30
40
50
60
70
80
0 0,5 1 1,5 2 2,5 3
VOP (V)
IOP (uA)
I/O PIN PULL-UP RESISTOR CURRENT vs. INPUT VOLTAGE
VCC = 5V
85 ˚C
25 ˚C
-40 ˚C
0
20
40
60
80
100
120
140
160
0123456
VOP (V)
IOP (uA)ATtiny25/45/85 [DATASHEET] 181
2586Q–AVR–08/2013
Figure 22-16. Reset Pull-up Resistor Current vs. Reset Pin Voltage (VCC = 1.8V)
Figure 22-17. Reset Pull-up Resistor Current vs. Reset Pin Voltage (VCC = 2.7V)
RESET PULL-UP RESISTOR CURRENT vs. RESET PIN VOLTAGE
VCC = 1.8V
85 ˚C
25 ˚C
-40 ˚C
0
5
10
15
20
25
30
35
40
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2
VRESET (V)
IRESET (uA)
RESET PULL-UP RESISTOR CURRENT vs. RESET PIN VOLTAGE
VCC =2.7V
85 ˚C
25 ˚C
-40 ˚C
0
10
20
30
40
50
60
0 0,5 1 1,5 2 2,5 3
VRESET (V)
IRESET (uA)ATtiny25/45/85 [DATASHEET] 182
2586Q–AVR–08/2013
Figure 22-18. Reset Pull-up Resistor Current vs. Reset Pin Voltage (VCC = 5V)
22.6 Pin Driver Strength
Figure 22-19. I/O Pin Output Voltage vs. Sink Current (VCC = 3V)
RESET PULL-UP RESISTOR CURRENT vs. RESET PIN VOLTAGE
VCC = 5V
85 ˚C
25 ˚C
-40 ˚C
0
20
40
60
80
100
120
0123456
VRESET (V)
IRESET (uA)
I/O PIN OUTPUT VOLTAGE vs. SINK CURRENT
VCC = 3V
85
25
-40
0
0,2
0,4
0,6
0,8
1
1,2
0 5 10 15 20 25
IOL (mA)
VOL (V)ATtiny25/45/85 [DATASHEET] 183
2586Q–AVR–08/2013
Figure 22-20. I/O Pin Output Voltage vs. Sink Current (VCC = 5V)
Figure 22-21. I/O Pin Output Voltage vs. Source Current (VCC = 3V)
I/O PIN OUTPUT VOLTAGE vs. SINK CURRENT
VCC = 5V
85
25
-40
0
0,1
0,2
0,3
0,4
0,5
0,6
0 5 10 15 20 25
IOL (mA)
VOL (V)
I/O PIN OUTPUT VOLTAGE vs. SOURCE CURRENT
VCC = 3V
85
25
-40
0
0,5
1
1,5
2
2,5
3
3,5
0 5 10 15 20 25
IOH (mA)
VOH (V)ATtiny25/45/85 [DATASHEET] 184
2586Q–AVR–08/2013
Figure 22-22. I/O Pin Output Voltage vs. Source Current (VCC = 5V)
Figure 22-23. Reset Pin Output Voltage vs. Sink Current (VCC = 3V)
I/O PIN OUTPUT VOLTAGE vs. SOURCE CURRENT
VCC = 5V
85
25
-40
4,4
4,5
4,6
4,7
4,8
4,9
5
5,1
0 5 10 15 20 25
IOH (mA)
VOH (V)
RESET AS I/O PIN OUTPUT VOLTAGE vs. SINK CURRENT
VCC = 3V
-45 °C
0 °C
85 °C
0
0.5
1
1.5
0 0.5 1 1.5 2 2.5 3
IOL (mA)
VOL (V)ATtiny25/45/85 [DATASHEET] 185
2586Q–AVR–08/2013
Figure 22-24. Reset Pin Output Voltage vs. Sink Current (VCC = 5V)
Figure 22-25. Reset Pin Output Voltage vs. Source Current (VCC = 3V)
RESET AS I/O PIN OUTPUT VOLTAGE vs. SINK CURRENT
VCC = 5V
-45 °C
0 °C
85 °C
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2 2.5 3
IOL (mA)
VOL (V)
RESET AS I/O PIN OUTPUT VOLTAGE vs. SOURCE CURRENT
VCC = 3V
-45 °C
25 °C
85 °C
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2
IOH (mA)
VOH (V)ATtiny25/45/85 [DATASHEET] 186
2586Q–AVR–08/2013
Figure 22-26. Reset Pin Output Voltage vs. Source Current (VCC = 5V)
22.7 Pin Threshold and Hysteresis
Figure 22-27. I/O Pin Input Threshold Voltage vs. VCC (VIH, IO Pin Read as ‘1’)
RESET AS I/O PIN OUTPUT VOLTAGE vs. SOURCE CURRENT
VCC = 5V
-45 °C
25 °C
2.5 85 °C
3
3.5
4
4.5
5
0 0.5 1 1.5 2
IOH (mA)
VOH (V)
I/O PIN INPUT THRESHOLD VOLTAGE vs. VCC
VIH, IO PIN READ AS '1'
85 ˚C
25 ˚C
-40 ˚C
0
0,5
1
1,5
2
2,5
3
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Threshold (V)ATtiny25/45/85 [DATASHEET] 187
2586Q–AVR–08/2013
Figure 22-28. I/O Pin Input Threshold Voltage vs. VCC (VIL, IO Pin Read as ‘0’)
Figure 22-29. I/O Pin Input Hysteresis vs. VCC
I/O PIN INPUT THRESHOLD VOLTAGE vs. VCC
VIL, IO PIN READ AS '0'
85 ˚C
25 ˚C
-40 ˚C
0
0,5
1
1,5
2
2,5
3
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Threshold (V)
85 °C
25 °C
-40 °C
0
0,1
0,2
0,3
0,4
0,5
0,6
1,5 2 2,5 3 3,5 4 4,5 5 5,5
Input Hysteresis (V)
V CC (V)
I/O PIN INPUT HYSTERESIS vs. VCCATtiny25/45/85 [DATASHEET] 188
2586Q–AVR–08/2013
Figure 22-30. Reset Input Threshold Voltage vs. VCC (VIH, IO Pin Read as ‘1’)
Figure 22-31. Reset Input Threshold Voltage vs. VCC (VIL, IO Pin Read as ‘0’)
RESET INPUT THRESHOLD VOLTAGE vs. VCC
VIH, IO PIN READ AS '1'
85 °C
25 °C
-40 °C
0
0,5
1
1,5
2
2,5
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Threshold (V)
RESET INPUT THRESHOLD VOLTAGE vs. VCC
VIL, IO PIN READ AS '0'
85 °C
25 °C
-40 °C
0
0,5
1
1,5
2
2,5
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Threshold (V)ATtiny25/45/85 [DATASHEET] 189
2586Q–AVR–08/2013
Figure 22-32. Reset Pin Input Hysteresis vs. VCC
22.8 BOD Threshold
Figure 22-33. BOD Threshold vs. Temperature (BOD Level is 4.3V)
RESET PIN INPUT HYSTERESIS vs. VCC
85 °C
25 °C
-40 °C
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
0,5
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Input Hysteresis (V)
BOD THRESHOLDS vs. TEMPERATURE
Rising VCC
Falling VCC
4,26
4,28
4,3
4,32
4,34
4,36
4,38
4,4
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature (C)
Threshold (V)ATtiny25/45/85 [DATASHEET] 190
2586Q–AVR–08/2013
Figure 22-34. BOD Threshold vs. Temperature (BOD Level is 2.7V)
Figure 22-35. BOD Threshold vs. Temperature (BOD Level is 1.8V)
BOD THRESHOLDS vs. TEMPERATURE
Rising VCC
Falling VCC
2,68
2,7
2,72
2,74
2,76
2,78
2,8
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature (C)
Threshold (V)
BOD THRESHOLDS vs. TEMPERATURE
Rising VCC
Falling VCC
1,795
1,8
1,805
1,81
1,815
1,82
1,825
1,83
1,835
1,84
1,845
1,85
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature (C)
Threshold (V)ATtiny25/45/85 [DATASHEET] 191
2586Q–AVR–08/2013
Figure 22-36. Bandgap Voltage vs. Supply Voltage
Figure 22-37. Bandgap Voltage vs. Temperature
BANDGAP VOLTAGE vs. VCC
85 °C
25 °C
-40 °C
1
1,02
1,04
1,06
1,08
1,1
1,12
1,14
1,16
1,18
1,2
1,5 2 2,5 3 3,5 4 4,5 5 5,5
Vcc (V)
Bandgap Voltage (V)
BANDGAP VOLTAGE vs. Temperature
5 V
3 V
1.8 V
1
1,02
1,04
1,06
1,08
1,1
1,12
1,14
1,16
1,18
1,2
-40 -20 0 20 40 60 80 100
Temperature
Bandgap Voltage (V)ATtiny25/45/85 [DATASHEET] 192
2586Q–AVR–08/2013
22.9 Internal Oscillator Speed
Figure 22-38. Watchdog Oscillator Frequency vs. VCC
Figure 22-39. Watchdog Oscillator Frequency vs. Temperature
WATCHDOG OSCILLATOR FREQUENCY vs. VCC
85 ˚C
25 ˚C
-40 ˚C
0,112
0,114
0,116
0,118
0,12
0,122
0,124
0,126
0,128
2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
FRC (MHz)
WATCHDOG OSCILLATOR FREQUENCY vs. TEMPERATURE
5.5 V
4.0 V
3.3 V
2.7 V
1.8 V
0,108
0,11
0,112
0,114
0,116
0,118
0,12
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature
FRC (MHz)ATtiny25/45/85 [DATASHEET] 193
2586Q–AVR–08/2013
Figure 22-40. Calibrated 8 MHz RC Oscillator Frequency vs. VCC
Figure 22-41. Calibrated 8 MHz RC Oscillator Frequency vs. Temperature
CALIBRATED 8 MHz RC OSCILLATOR FREQUENCY vs. VCC
85 ˚C
25 ˚C
-40 ˚C
7,5
7,6
7,7
7,8
7,9
8
8,1
8,2
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
FRC (MHz)
CALIBRATED 8 MHz RC OSCILLATOR FREQUENCY vs. TEMPERATURE
5.0 V
3.0 V
7,7
7,75
7,8
7,85
7,9
7,95
8
8,05
8,1
8,15
-60 -40 -20 0 20 40 60 80 100
Temperature
FRC (MHz)ATtiny25/45/85 [DATASHEET] 194
2586Q–AVR–08/2013
Figure 22-42. Calibrated 8 MHz RC Oscillator Frequency vs. OSCCAL Value
Figure 22-43. Calibrated 1.6 MHz RC Oscillator Frequency vs. VCC
CALIBRATED 8 MHz RC OSCILLATOR FREQUENCY vs. OSCCAL VALUE
85 ˚C
25 ˚C
-40 ˚C
0
2
4
6
8
10
12
14
16
18
0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240
OSCCAL (X1)
FRC (MHz)
CALIBRATED 1.6 MHz RC OSCILLATOR FREQUENCY vs. VCC
85 ˚C
25 ˚C
-40 ˚C
1,4
1,45
1,5
1,55
1,6
1,65
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
FRC (MHz)ATtiny25/45/85 [DATASHEET] 195
2586Q–AVR–08/2013
Figure 22-44. Calibrated 1.6 MHz RC Oscillator Frequency vs. Temperature
Figure 22-45. Calibrated 1.6 MHz RC Oscillator Frequency vs. OSCCAL Value
CALIBRATED 1.6MHz RC OSCILLATOR FREQUENCY vs. TEMPERATURE
5.0 V
3.0 V
1,5
1,52
1,54
1,56
1,58
1,6
1,62
1,64
-60 -40 -20 0 20 40 60 80 100
Temperature
FRC (MHz)
CALIBRATED 1.6 MHz RC OSCILLATOR FREQUENCY vs. OSCCAL VALUE
85 ˚C
25 ˚C
-40 ˚C
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240
OSCCAL (X1)
FRC (MHz)ATtiny25/45/85 [DATASHEET] 196
2586Q–AVR–08/2013
22.10 Current Consumption of Peripheral Units
Figure 22-46. Brownout Detector Current vs. VCC
Figure 22-47. ADC Current vs. VCC (AREF = AVCC)
BROWNOUT DETECTOR CURRENT vs. VCC
85 °C
25 °C
-40 °C
0
5
10
15
20
25
30
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (uA)
ADC CURRENT vs. VCC
AREF = AVCC
85 °C
25 °C
-40 °C
0
50
100
150
200
250
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (uA)ATtiny25/45/85 [DATASHEET] 197
2586Q–AVR–08/2013
Figure 22-48. Analog Comparator Current vs. VCC
Figure 22-49. Programming Current vs. VCC
ANALOG COMPARATOR CURRENT vs. VCC
85 °C
25 °C
-40 °C
0
5
10
15
20
25
30
35
40
45
50
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (uA)
PROGRAMMING CURRENT vs. Vcc
Ext Clk
85 °C
25 °C
-40 °C
0
2
4
6
8
10
12
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
ICC (mA)ATtiny25/45/85 [DATASHEET] 198
2586Q–AVR–08/2013
22.11 Current Consumption in Reset and Reset Pulsewidth
Figure 22-50. Reset Supply Current vs. VCC (0.1 - 1.0 MHz, Excluding Current Through The Reset Pull-up)
Figure 22-51. Reset Supply Current vs. VCC (1 - 20 MHz, Excluding Current Through The Reset Pull-up)
RESET SUPPLY CURRENT vs. VCC
0.1 - 1.0 MHz, EXCLUDING CURRENT THROUGH THE RESET PULLUP
5.5 V
5.0 V
4.5 V
4.0 V
3.3 V
2.7 V
1.8 V
0
0,02
0,04
0,06
0,08
0,1
0,12
0,14
0,16
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Frequency (MHz)
ICC (mA)
RESET SUPPLY CURRENT vs. VCC
1 - 20 MHz, EXCLUDING CURRENT THROUGH THE RESET PULLUP
5.5 V
5.0 V
4.5 V
0
0,5
1
1,5
2
2,5
0 2 4 6 8 10 12 14 16 18 20
Frequency (MHz)
ICC (mA)
1.8V
2.7V
3.3V
4.0VATtiny25/45/85 [DATASHEET] 199
2586Q–AVR–08/2013
Figure 22-52. Minimum Reset Pulse Width vs. VCC
MINIMUM RESET PULSE WIDTH vs. VCC
85 ˚C
25 ˚C
-40 ˚C
0
500
1000
1500
2000
2500
1,5 2 2,5 3 3,5 4 4,5 5 5,5
VCC (V)
Pulsewidth (ns)ATtiny25/45/85 [DATASHEET] 200
2586Q–AVR–08/2013
23. Register Summary
Note: 1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
0x3F SREG I T H S V N Z C page 8
0x3E SPH – – – – – – SP9 SP8 page 11
0x3D SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 page 11
0x3C Reserved –
0x3B GIMSK – INT0 PCIE – – – – – page 51
0x3A GIFR – INTF0 PCIF – – – – – page 52
0x39 TIMSK – OCIE1A OCIE1B OCIE0A OCIE0B TOIE1 TOIE0 – pages 81, 102
0x38 TIFR – OCF1A OCF1B OCF0A OCF0B TOV1 TOV0 – page 81
0x37 SPMCSR – – RSIG CTPB RFLB PGWRT PGERS SPMEN page 145
0x36 Reserved –
0x35 MCUCR BODS PUD SE SM1 SM0 BODSE ISC01 ISC00 pages 37, 51, 64
0x34 MCUSR – – – – WDRF BORF EXTRF PORF page 44,
0x33 TCCR0B FOC0A FOC0B – – WGM02 CS02 CS01 CS00 page 79
0x32 TCNT0 Timer/Counter0 page 80
0x31 OSCCAL Oscillator Calibration Register page 31
0x30 TCCR1 CTC1 PWM1A COM1A1 COM1A0 CS13 CS12 CS11 CS10 pages 89, 100
0x2F TCNT1 Timer/Counter1 pages 91, 102
0x2E OCR1A Timer/Counter1 Output Compare Register A pages 91, 102
0x2D OCR1C Timer/Counter1 Output Compare Register C pages 91, 102
0x2C GTCCR TSM PWM1B COM1B1 COM1B0 FOC1B FOC1A PSR1 PSR0 pages 77, 90, 101
0x2B OCR1B Timer/Counter1 Output Compare Register B page 92
0x2A TCCR0A COM0A1 COM0A0 COM0B1 COM0B0 – WGM01 WGM00 page 77
0x29 OCR0A Timer/Counter0 – Output Compare Register A page 80
0x28 OCR0B Timer/Counter0 – Output Compare Register B page 81
0x27 PLLCSR LSM – – – – PCKE PLLE PLOCK pages 94, 103
0x26 CLKPR CLKPCE – – – CLKPS3 CLKPS2 CLKPS1 CLKPS0 page 32
0x25 DT1A DT1AH3 DT1AH2 DT1AH1 DT1AH0 DT1AL3 DT1AL2 DT1AL1 DT1AL0 page 107
0x24 DT1B DT1BH3 DT1BH2 DT1BH1 DT1BH0 DT1BL3 DT1BL2 DT1BL1 DT1BL0 page 107
0x23 DTPS1 - - - - - - DTPS11 DTPS10 page 106
0x22 DWDR DWDR[7:0] page 140
0x21 WDTCR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0 page 45
0x20 PRR – PRTIM1 PRTIM0 PRUSI PRADC page 36
0x1F EEARH EEAR8 page 20
0x1E EEARL EEAR7 EEAR6 EEAR5 EEAR4 EEAR3 EEAR2 EEAR1 EEAR0 page 21
0x1D EEDR EEPROM Data Register page 21
0x1C EECR – – EEPM1 EEPM0 EERIE EEMPE EEPE EERE page 21
0x1B Reserved –
0x1A Reserved –
0x19 Reserved –
0x18 PORTB – – PORTB5 PORTB4 PORTB3 PORTB2 PORTB1 PORTB0 page 64
0x17 DDRB – – DDB5 DDB4 DDB3 DDB2 DDB1 DDB0 page 64
0x16 PINB – – PINB5 PINB4 PINB3 PINB2 PINB1 PINB0 page 64
0x15 PCMSK – – PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 page 52
0x14 DIDR0 – – ADC0D ADC2D ADC3D ADC1D AIN1D AIN0D pages 121, 138
0x13 GPIOR2 General Purpose I/O Register 2 page 10
0x12 GPIOR1 General Purpose I/O Register 1 page 10
0x11 GPIOR0 General Purpose I/O Register 0 page 10
0x10 USIBR USI Buffer Register page 115
0x0F USIDR USI Data Register page 115
0x0E USISR USISIF USIOIF USIPF USIDC USICNT3 USICNT2 USICNT1 USICNT0 page 115
0x0D USICR USISIE USIOIE USIWM1 USIWM0 USICS1 USICS0 USICLK USITC page 116
0x0C Reserved –
0x0B Reserved –
0x0A Reserved –
0x09 Reserved –
0x08 ACSR ACD ACBG ACO ACI ACIE – ACIS1 ACIS0 page 120
0x07 ADMUX REFS1 REFS0 ADLAR REFS2 MUX3 MUX2 MUX1 MUX0 page 134
0x06 ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 page 136
0x05 ADCH ADC Data Register High Byte page 137
0x04 ADCL ADC Data Register Low Byte page 137
0x03 ADCSRB BIN ACME IPR – – ADTS2 ADTS1 ADTS0 pages 120, 137
0x02 Reserved –
0x01 Reserved –
0x00 Reserved –ATtiny25/45/85 [DATASHEET] 201
2586Q–AVR–08/2013
should never be written.
2. I/O Registers within the address range 0x00 - 0x1F are directly bit-accessible using the SBI and CBI instructions. In these
registers, the value of single bits can be checked by using the SBIS and SBIC instructions.
3. Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most other AVRs, the CBI and SBI
instructions will only operation the specified bit, and can therefore be used on registers containing such Status Flags. The
CBI and SBI instructions work with registers 0x00 to 0x1F only.ATtiny25/45/85 [DATASHEET] 202
2586Q–AVR–08/2013
24. Instruction Set Summary
Mnemonics Operands Description Operation Flags #Clocks
ARITHMETIC AND LOGIC INSTRUCTIONS
ADD Rd, Rr Add two Registers Rd Rd + Rr Z,C,N,V,H 1
ADC Rd, Rr Add with Carry two Registers Rd Rd + Rr + C Z,C,N,V,H 1
ADIW Rdl,K Add Immediate to Word Rdh:Rdl Rdh:Rdl + K Z,C,N,V,S 2
SUB Rd, Rr Subtract two Registers Rd Rd - Rr Z,C,N,V,H 1
SUBI Rd, K Subtract Constant from Register Rd Rd - K Z,C,N,V,H 1
SBC Rd, Rr Subtract with Carry two Registers Rd Rd - Rr - C Z,C,N,V,H 1
SBCI Rd, K Subtract with Carry Constant from Reg. Rd Rd - K - C Z,C,N,V,H 1
SBIW Rdl,K Subtract Immediate from Word Rdh:Rdl Rdh:Rdl - K Z,C,N,V,S 2
AND Rd, Rr Logical AND Registers Rd Rd Rr Z,N,V 1
ANDI Rd, K Logical AND Register and Constant Rd Rd K Z,N,V 1
OR Rd, Rr Logical OR Registers Rd Rd v Rr Z,N,V 1
ORI Rd, K Logical OR Register and Constant Rd Rd v K Z,N,V 1
EOR Rd, Rr Exclusive OR Registers Rd Rd Rr Z,N,V 1
COM Rd One’s Complement Rd 0xFF Rd Z,C,N,V 1
NEG Rd Two’s Complement Rd 0x00 Rd Z,C,N,V,H 1
SBR Rd,K Set Bit(s) in Register Rd Rd v K Z,N,V 1
CBR Rd,K Clear Bit(s) in Register Rd Rd (0xFF - K) Z,N,V 1
INC Rd Increment Rd Rd + 1 Z,N,V 1
DEC Rd Decrement Rd Rd 1 Z,N,V 1
TST Rd Test for Zero or Minus Rd Rd Rd Z,N,V 1
CLR Rd Clear Register Rd Rd Rd Z,N,V 1
SER Rd Set Register Rd 0xFF None 1
BRANCH INSTRUCTIONS
RJMP k Relative Jump PC PC + k + 1 None 2
IJMP Indirect Jump to (Z) PC Z None 2
RCALL k Relative Subroutine Call PC PC + k + 1 None 3
ICALL Indirect Call to (Z) PC Z None 3
RET Subroutine Return PC STACK None 4
RETI Interrupt Return PC STACK I 4
CPSE Rd,Rr Compare, Skip if Equal if (Rd = Rr) PC PC + 2 or 3 None 1/2/3
CP Rd,Rr Compare Rd Rr Z, N,V,C,H 1
CPC Rd,Rr Compare with Carry Rd Rr C Z, N,V,C,H 1
CPI Rd,K Compare Register with Immediate Rd K Z, N,V,C,H 1
SBRC Rr, b Skip if Bit in Register Cleared if (Rr(b)=0) PC PC + 2 or 3 None 1/2/3
SBRS Rr, b Skip if Bit in Register is Set if (Rr(b)=1) PC PC + 2 or 3 None 1/2/3
SBIC P, b Skip if Bit in I/O Register Cleared if (P(b)=0) PC PC + 2 or 3 None 1/2/3
SBIS P, b Skip if Bit in I/O Register is Set if (P(b)=1) PC PC + 2 or 3 None 1/2/3
BRBS s, k Branch if Status Flag Set if (SREG(s) = 1) then PCPC+k + 1 None 1/2
BRBC s, k Branch if Status Flag Cleared if (SREG(s) = 0) then PCPC+k + 1 None 1/2
BREQ k Branch if Equal if (Z = 1) then PC PC + k + 1 None 1/2
BRNE k Branch if Not Equal if (Z = 0) then PC PC + k + 1 None 1/2
BRCS k Branch if Carry Set if (C = 1) then PC PC + k + 1 None 1/2
BRCC k Branch if Carry Cleared if (C = 0) then PC PC + k + 1 None 1/2
BRSH k Branch if Same or Higher if (C = 0) then PC PC + k + 1 None 1/2
BRLO k Branch if Lower if (C = 1) then PC PC + k + 1 None 1/2
BRMI k Branch if Minus if (N = 1) then PC PC + k + 1 None 1/2
BRPL k Branch if Plus if (N = 0) then PC PC + k + 1 None 1/2
BRGE k Branch if Greater or Equal, Signed if (N V= 0) then PC PC + k + 1 None 1/2
BRLT k Branch if Less Than Zero, Signed if (N V= 1) then PC PC + k + 1 None 1/2
BRHS k Branch if Half Carry Flag Set if (H = 1) then PC PC + k + 1 None 1/2
BRHC k Branch if Half Carry Flag Cleared if (H = 0) then PC PC + k + 1 None 1/2
BRTS k Branch if T Flag Set if (T = 1) then PC PC + k + 1 None 1/2
BRTC k Branch if T Flag Cleared if (T = 0) then PC PC + k + 1 None 1/2
BRVS k Branch if Overflow Flag is Set if (V = 1) then PC PC + k + 1 None 1/2
BRVC k Branch if Overflow Flag is Cleared if (V = 0) then PC PC + k + 1 None 1/2
BRIE k Branch if Interrupt Enabled if ( I = 1) then PC PC + k + 1 None 1/2
BRID k Branch if Interrupt Disabled if ( I = 0) then PC PC + k + 1 None 1/2
BIT AND BIT-TEST INSTRUCTIONS
SBI P,b Set Bit in I/O Register I/O(P,b) 1 None 2
CBI P,b Clear Bit in I/O Register I/O(P,b) 0 None 2
LSL Rd Logical Shift Left Rd(n+1) Rd(n), Rd(0) 0 Z,C,N,V 1
LSR Rd Logical Shift Right Rd(n) Rd(n+1), Rd(7) 0 Z,C,N,V 1
ROL Rd Rotate Left Through Carry Rd(0)C,Rd(n+1) Rd(n),CRd(7) Z,C,N,V 1
ROR Rd Rotate Right Through Carry Rd(7)C,Rd(n) Rd(n+1),CRd(0) Z,C,N,V 1
ASR Rd Arithmetic Shift Right Rd(n) Rd(n+1), n=0..6 Z,C,N,V 1ATtiny25/45/85 [DATASHEET] 203
2586Q–AVR–08/2013
SWAP Rd Swap Nibbles Rd(3..0)Rd(7..4),Rd(7..4)Rd(3..0) None 1
BSET s Flag Set SREG(s) 1 SREG(s) 1
BCLR s Flag Clear SREG(s) 0 SREG(s) 1
BST Rr, b Bit Store from Register to T T Rr(b) T 1
BLD Rd, b Bit load from T to Register Rd(b) T None 1
SEC Set Carry C 1 C1
CLC Clear Carry C 0 C 1
SEN Set Negative Flag N 1 N1
CLN Clear Negative Flag N 0 N 1
SEZ Set Zero Flag Z 1 Z1
CLZ Clear Zero Flag Z 0 Z 1
SEI Global Interrupt Enable I 1 I1
CLI Global Interrupt Disable I 0 I 1
SES Set Signed Test Flag S 1 S1
CLS Clear Signed Test Flag S 0 S 1
SEV Set Twos Complement Overflow. V 1 V1
CLV Clear Twos Complement Overflow V 0 V 1
SET Set T in SREG T 1 T1
CLT Clear T in SREG T 0 T 1
SEH Set Half Carry Flag in SREG H 1 H1
CLH Clear Half Carry Flag in SREG H 0 H 1
DATA TRANSFER INSTRUCTIONS
MOV Rd, Rr Move Between Registers Rd Rr None 1
MOVW Rd, Rr Copy Register Word Rd+1:Rd Rr+1:Rr None 1
LDI Rd, K Load Immediate Rd K None 1
LD Rd, X Load Indirect Rd (X) None 2
LD Rd, X+ Load Indirect and Post-Inc. Rd (X), X X + 1 None 2
LD Rd, - X Load Indirect and Pre-Dec. X X - 1, Rd (X) None 2
LD Rd, Y Load Indirect Rd (Y) None 2
LD Rd, Y+ Load Indirect and Post-Inc. Rd (Y), Y Y + 1 None 2
LD Rd, - Y Load Indirect and Pre-Dec. Y Y - 1, Rd (Y) None 2
LDD Rd,Y+q Load Indirect with Displacement Rd (Y + q) None 2
LD Rd, Z Load Indirect Rd (Z) None 2
LD Rd, Z+ Load Indirect and Post-Inc. Rd (Z), Z Z+1 None 2
LD Rd, -Z Load Indirect and Pre-Dec. Z Z - 1, Rd (Z) None 2
LDD Rd, Z+q Load Indirect with Displacement Rd (Z + q) None 2
LDS Rd, k Load Direct from SRAM Rd (k) None 2
ST X, Rr Store Indirect (X) Rr None 2
ST X+, Rr Store Indirect and Post-Inc. (X) Rr, X X + 1 None 2
ST - X, Rr Store Indirect and Pre-Dec. X X - 1, (X) Rr None 2
ST Y, Rr Store Indirect (Y) Rr None 2
ST Y+, Rr Store Indirect and Post-Inc. (Y) Rr, Y Y + 1 None 2
ST - Y, Rr Store Indirect and Pre-Dec. Y Y - 1, (Y) Rr None 2
STD Y+q,Rr Store Indirect with Displacement (Y + q) Rr None 2
ST Z, Rr Store Indirect (Z) Rr None 2
ST Z+, Rr Store Indirect and Post-Inc. (Z) Rr, Z Z + 1 None 2
ST -Z, Rr Store Indirect and Pre-Dec. Z Z - 1, (Z) Rr None 2
STD Z+q,Rr Store Indirect with Displacement (Z + q) Rr None 2
STS k, Rr Store Direct to SRAM (k) Rr None 2
LPM Load Program Memory R0 (Z) None 3
LPM Rd, Z Load Program Memory Rd (Z) None 3
LPM Rd, Z+ Load Program Memory and Post-Inc Rd (Z), Z Z+1 None 3
SPM Store Program Memory (z) R1:R0 None
IN Rd, P In Port Rd P None 1
OUT P, Rr Out Port P Rr None 1
PUSH Rr Push Register on Stack STACK Rr None 2
POP Rd Pop Register from Stack Rd STACK None 2
MCU CONTROL INSTRUCTIONS
NOP No Operation None 1
SLEEP Sleep (see specific descr. for Sleep function) None 1
WDR Watchdog Reset (see specific descr. for WDR/Timer) None 1
BREAK Break For On-chip Debug Only None N/A
Mnemonics Operands Description Operation Flags #ClocksATtiny25/45/85 [DATASHEET] 204
2586Q–AVR–08/2013
25. Ordering Information
Notes: 1. For speed vs. supply voltage, see section 21.3 “Speed” on page 163.
2. All Pb-free, halide-free, fully green, and comply with European directive for Restriction of Hazardous Substances (RoHS).
3. Code indicators: H = NiPdAu lead finish, U/N = matte tin, R = tape & reel.
4. Can also be supplied in wafer form. Contact your local Atmel sales office for ordering information and minimum quantities.
5. For characteristics, see “Appendix A – Specification at 105C”.
6. For characteristics, see “Appendix B – Specification at 125C”.
25.1 ATtiny25
Speed (MHz) (1) Supply Voltage (V) Temperature Range Package (2) Ordering Code (3)
10 1.8 – 5.5
Industrial
(-40C to +85C) (4)
8P3 ATtiny25V-10PU
8S2
ATtiny25V-10SU
ATtiny25V-10SUR
ATtiny25V-10SH
ATtiny25V-10SHR
S8S1
ATtiny25V-10SSU
ATtiny25V-10SSUR
ATtiny25V-10SSH
ATtiny25V-10SSHR
20M1 ATtiny25V-10MU
ATtiny25V-10MUR
Industrial
(-40C to +105C) (5)
8S2 ATtiny25V-10SN
ATtiny25V-10SNR
S8S1 ATtiny25V-10SSN
ATtiny25V-10SSNR
Industrial (-40C to +125C) (6) 20M1 ATtiny25V-10MF
ATtiny25V-10MFR
20 2.7 – 5.5
Industrial
(-40C to +85C) (4)
8P3 ATtiny25-20PU
8S2
ATtiny25-20SU
ATtiny25-20SUR
ATtiny25-20SH
ATtiny25-20SHR
S8S1
ATtiny25-20SSU
ATtiny25-20SSUR
ATtiny25-20SSH
ATtiny25-20SSHR
20M1 ATtiny25-20MU
ATtiny25-20MUR
Industrial
(-40C to +105C) (5)
8S2 ATtiny25-20SN
ATtiny25-20SNR
S8S1 ATtiny25-20SSN
ATtiny25-20SSNR
Industrial (-40C to +125C) (6) 20M1 ATtiny25-20MF
ATtiny25-20MFR
Package Types
8P3 8-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
8S2 8-lead, 0.208" Wide, Plastic Gull-Wing Small Outline (EIAJ SOIC)
S8S1 8-lead, 0.150" Wide, Plastic Gull-Wing Small Outline (JEDEC SOIC)
20M1 20-pad, 4 x 4 x 0.8 mm Body, Quad Flat No-Lead/Micro Lead Frame Package (QFN/MLF)ATtiny25/45/85 [DATASHEET] 205
2586Q–AVR–08/2013
Notes: 1. For speed vs. supply voltage, see section 21.3 “Speed” on page 163.
2. All packages are Pb-free, halide-free and fully green and they comply with the European directive for Restriction of Hazardous
Substances (RoHS).
3. Code indicators:
– H: NiPdAu lead finish
– U: matte tin
– R: tape & reel
4. These devices can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information
and minimum quantities.
25.2 ATtiny45
Speed (MHz) (1) Supply Voltage (V) Temperature Range Package (2) Ordering Code (3)
10 1.8 – 5.5 Industrial
(-40C to +85C) (4)
8P3 ATtiny45V-10PU
8S2
ATtiny45V-10SU
ATtiny45V-10SUR
ATtiny45V-10SH
ATtiny45V-10SHR
8X ATtiny45V-10XU
ATtiny45V-10XUR
20M1 ATtiny45V-10MU
ATtiny45V-10MUR
20 2.7 – 5.5 Industrial
(-40C to +85C) (4)
8P3 ATtiny45-20PU
8S2
ATtiny45-20SU
ATtiny45-20SUR
ATtiny45-20SH
ATtiny45-20SHR
8X ATtiny45-20XU
ATtiny45-20XUR
20M1 ATtiny45-20MU
ATtiny45-20MUR
Package Types
8P3 8-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
8S2 8-lead, 0.208" Wide, Plastic Gull-Wing Small Outline (EIAJ SOIC)
8X 8-lead, 4.4 mm Wide, Plastic Thin Shrink Small Outline Package (TSSOP)
20M1 20-pad, 4 x 4 x 0.8 mm Body, Quad Flat No-Lead/Micro Lead Frame Package (QFN/MLF)ATtiny25/45/85 [DATASHEET] 206
2586Q–AVR–08/2013
Notes: 1. For speed vs. supply voltage, see section 21.3 “Speed” on page 163.
2. All packages are Pb-free, halide-free and fully green and they comply with the European directive for Restriction of Hazardous
Substances (RoHS).
3. Code indicators:
– H: NiPdAu lead finish
– U: matte tin
– R: tape & reel
4. These devices can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information
and minimum quantities.
25.3 ATtiny85
Speed (MHz) (1) Supply Voltage (V) Temperature Range Package (2) Ordering Code (3)
10 1.8 – 5.5 Industrial
(-40C to +85C) (4)
8P3 ATtiny85V-10PU
8S2
ATtiny85V-10SU
ATtiny85V-10SUR
ATtiny85V-10SH
ATtiny85V-10SHR
20M1 ATtiny85V-10MU
ATtiny85V-10MUR
20 2.7 – 5.5 Industrial
(-40C to +85C) (4)
8P3 ATtiny85-20PU
8S2
ATtiny85-20SU
ATtiny85-20SUR
ATtiny85-20SH
ATtiny85-20SHR
20M1 ATtiny85-20MU
ATtiny85-20MUR
Package Types
8P3 8-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
8S2 8-lead, 0.208" Wide, Plastic Gull-Wing Small Outline (EIAJ SOIC)
20M1 20-pad, 4 x 4 x 0.8 mm Body, Quad Flat No-Lead/Micro Lead Frame Package (QFN/MLF)ATtiny25/45/85 [DATASHEET] 207
2586Q–AVR–08/2013
26. Packaging Information
26.1 8P3
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
8P3, 8-lead, 0.300" Wide Body, Plastic Dual
In-line Package (PDIP)
01/09/02
8P3 B
D
D1
E
E1
e
b2 L
b
A2 A
1
N
eA
c
b3
4 PLCS
Top View
Side View
End View
COMMON DIMENSIONS
(Unit of Measure = inches)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This drawing is for general information only; refer to JEDEC Drawing MS-001, Variation BA for additional information.
2. Dimensions A and L are measured with the package seated in JEDEC seating plane Gauge GS-3.
3. D, D1 and E1 dimensions do not include mold Flash or protrusions. Mold Flash or protrusions shall not exceed 0.010 inch.
4. E and eA measured with the leads constrained to be perpendicular to datum.
5. Pointed or rounded lead tips are preferred to ease insertion.
6. b2 and b3 maximum dimensions do not include Dambar protrusions. Dambar protrusions shall not exceed 0.010 (0.25 mm).
A 0.210 2
A2 0.115 0.130 0.195
b 0.014 0.018 0.022 5
b2 0.045 0.060 0.070 6
b3 0.030 0.039 0.045 6
c 0.008 0.010 0.014
D 0.355 0.365 0.400 3
D1 0.005 3
E 0.300 0.310 0.325 4
E1 0.240 0.250 0.280 3
e 0.100 BSC
eA 0.300 BSC 4
L 0.115 0.130 0.150 2ATtiny25/45/85 [DATASHEET] 208
2586Q–AVR–08/2013
26.2 8S2
TITLE GPC DRAWING NO. REV.
Package Drawing Contact:
packagedrawings@atmel.com STN F 8S2
8S2, 8-lead, 0.208” Body, Plastic Small
Outline Package (EIAJ)
4/15/08
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This drawing is for general information only; refer to EIAJ Drawing EDR-7320 for additional information.
2. Mismatch of the upper and lower dies and resin burrs aren't included.
3. Determines the true geometric position.
4. Values b,C apply to plated terminal. The standard thickness of the plating layer shall measure between 0.007 to .021 mm.
A 1.70 2.16
A1 0.05 0.25
b 0.35 0.48 4
C 0.15 0.35 4
D 5.13 5.35
E1 5.18 5.40 2
E 7.70 8.26
L 0.51 0.85
θ 0° 8°
e 1.27 BSC 3
θ
1
N
E
TOP VIEW TOP VIEW
C
E1
END VIEW END VIEW
A
b
L
A1
e
D
SIDE VIEW SIDE VIEWATtiny25/45/85 [DATASHEET] 209
2586Q–AVR–08/2013
26.3 S8S1
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
S8S1, 8-lead, 0.150" Wide Body, Plastic Gull Wing Small
Outline (JEDEC SOIC)
7/28/03
S8S1 A
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This drawing is for general information only; refer to JEDEC Drawing MS-012 for proper dimensions, tolerances, datums,etc.
E 5.79 6.20
E1 3.81 3.99
A 1.35 1.75
A1 0.1 0.25
D 4.80 4.98
C 0.17 0.25
b 0.31 0.51
L 0.4 1.27
e 1.27 BSC
0o
8o
Top View
Side View
End View
1
N
C
A
A1
b
L
e
D
E1 EATtiny25/45/85 [DATASHEET] 210
2586Q–AVR–08/2013
26.4 8X
TITLE DRAWING NO.
R
REV.
Note: These drawings are for general information only. Refer to JEDEC Drawing MO-153AC.
2325 Orchard Parkway
San Jose, CA 95131
4/14/05
8X, 8-lead, 4.4 mm Body Width, Plastic Thin Shrink
Small Outline Package (TSSOP) 8X A
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A 1.05 1.10 1.20
A1 0.05 0.10 0.15
b 0.25 – 0.30
C – 0.127 –
D 2.90 3.05 3.10
E1 4.30 4.40 4.50
E 6.20 6.40 6.60
e 0.65 TYP
L 0.50 0.60 0.70
Ø 0o – 8o
C
A
b
L
A1
D
Side View
Top View
End View
E
1
E1
e
ØATtiny25/45/85 [DATASHEET] 211
2586Q–AVR–08/2013
26.5 20M1
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
20M1, 20-pad, 4 x 4 x 0.8 mm Body, Lead Pitch 0.50 mm, 20M1 B
10/27/04
2.6 mm Exposed Pad, Micro Lead Frame Package (MLF)
A 0.70 0.75 0.80
A1 – 0.01 0.05
A2 0.20 REF
b 0.18 0.23 0.30
D 4.00 BSC
D2 2.45 2.60 2.75
E 4.00 BSC
E2 2.45 2.60 2.75
e 0.50 BSC
L 0.35 0.40 0.55
SIDE VIEW
Pin 1 ID
Pin #1
Notch
(0.20 R)
BOTTOM VIEW
TOP VIEW
Note: Reference JEDEC Standard MO-220, Fig. 1 (SAW Singulation) WGGD-5.
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
D
E
e
A2
A1
A
D2
E2
0.08 C
L
1
2
3
b
1
2
3ATtiny25/45/85 [DATASHEET] 212
2586Q–AVR–08/2013
27. Errata
27.1 Errata ATtiny25
The revision letter in this section refers to the revision of the ATtiny25 device.
27.1.1 Rev D – F
No known errata.
27.1.2 Rev B – C
• EEPROM read may fail at low supply voltage / low clock frequency
1. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below 2V. If operating frequency
can not be raised above 1MHz then supply voltage should be more than 2V. Similarly, if supply voltage
can not be raised above 2V then operating frequency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterised. Guidelines are given for
room temperature, only.
27.1.3 Rev A
Not sampled.
27.2 Errata ATtiny45
The revision letter in this section refers to the revision of the ATtiny45 device.
27.2.1 Rev F – G
No known errata
27.2.2 Rev D – E
• EEPROM read may fail at low supply voltage / low clock frequency
1. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below 2V. If operating frequency
can not be raised above 1MHz then supply voltage should be more than 2V. Similarly, if supply voltage
can not be raised above 2V then operating frequency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterised. Guidelines are given for
room temperature, only.ATtiny25/45/85 [DATASHEET] 213
2586Q–AVR–08/2013
27.2.3 Rev B – C
• PLL not locking
• EEPROM read from application code does not work in Lock Bit Mode 3
• EEPROM read may fail at low supply voltage / low clock frequency
• Timer Counter 1 PWM output generation on OC1B- XOC1B does not work correctly
1. PLL not locking
When at frequencies below 6.0 MHz, the PLL will not lock
Problem fix / Workaround
When using the PLL, run at 6.0 MHz or higher.
2. EEPROM read from application code does not work in Lock Bit Mode 3
When the Memory Lock Bits LB2 and LB1 are programmed to mode 3, EEPROM read does not work from the
application code.
Problem Fix/Work around
Do not set Lock Bit Protection Mode 3 when the application code needs to read from EEPROM.
3. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below 2V. If operating frequency
can not be raised above 1MHz then supply voltage should be more than 2V. Similarly, if supply voltage
can not be raised above 2V then operating frequency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterised. Guidelines are given for
room temperature, only.
4. Timer Counter 1 PWM output generation on OC1B – XOC1B does not work correctly
Timer Counter1 PWM output OC1B-XOC1B does not work correctly. Only in the case when the control bits,
COM1B1 and COM1B0 are in the same mode as COM1A1 and COM1A0, respectively, the OC1B-XOC1B output
works correctly.
Problem Fix/Work around
The only workaround is to use same control setting on COM1A[1:0] and COM1B[1:0] control bits, see table 14-
4 in the data sheet. The problem has been fixed for Tiny45 rev D.
27.2.4 Rev A
• Too high power down power consumption
• DebugWIRE looses communication when single stepping into interrupts
• PLL not locking
• EEPROM read from application code does not work in Lock Bit Mode 3
• EEPROM read may fail at low supply voltage / low clock frequency
1. Too high power down power consumption
Three situations will lead to a too high power down power consumption. These are:
– An external clock is selected by fuses, but the I/O PORT is still enabled as an output.
– The EEPROM is read before entering power down.
– VCC is 4.5 volts or higher.
Problem fix / WorkaroundATtiny25/45/85 [DATASHEET] 214
2586Q–AVR–08/2013
– When using external clock, avoid setting the clock pin as Output.
– Do not read the EEPROM if power down power consumption is important.
– Use VCC lower than 4.5 Volts.
2. DebugWIRE looses communication when single stepping into interrupts
When receiving an interrupt during single stepping, debugwire will loose
communication.
Problem fix / Workaround
– When singlestepping, disable interrupts.
– When debugging interrupts, use breakpoints within the interrupt routine, and run into the interrupt.
3. PLL not locking
When at frequencies below 6.0 MHz, the PLL will not lock
Problem fix / Workaround
When using the PLL, run at 6.0 MHz or higher.
4. EEPROM read from application code does not work in Lock Bit Mode 3
When the Memory Lock Bits LB2 and LB1 are programmed to mode 3, EEPROM read does not work from the
application code.
Problem Fix/Work around
Do not set Lock Bit Protection Mode 3 when the application code needs to read from EEPROM.
5. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below 2V. If operating frequency
can not be raised above 1MHz then supply voltage should be more than 2V. Similarly, if supply voltage
can not be raised above 2V then operating frequency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterized. Guidelines are given for
room temperature, only.ATtiny25/45/85 [DATASHEET] 215
2586Q–AVR–08/2013
27.3 Errata ATtiny85
The revision letter in this section refers to the revision of the ATtiny85 device.
27.3.1 Rev B – C
No known errata.
27.3.2 Rev A
• EEPROM read may fail at low supply voltage / low clock frequency
1. EEPROM read may fail at low supply voltage / low clock frequency
Trying to read EEPROM at low clock frequencies and/or low supply voltage may result in invalid data.
Problem Fix/Workaround
Do not use the EEPROM when clock frequency is below 1MHz and supply voltage is below 2V. If operating frequency
can not be raised above 1MHz then supply voltage should be more than 2V. Similarly, if supply voltage
can not be raised above 2V then operating frequency should be more than 1MHz.
This feature is known to be temperature dependent but it has not been characterised. Guidelines are given for
room temperature, only.ATtiny25/45/85 [DATASHEET] 216
2586Q–AVR–08/2013
28. Datasheet Revision History
28.1 Rev. 2586Q-08/13
28.2 Rev. 2586P-06/13
28.3 Rev. 2586O-02/13
Updated ordering codes on page 204, page 205, and page 206.
28.4 Rev. 2586N-04/11
1. Added:
– Section “Capacitive Touch Sensing” on page 6.
2. Updated:
– Document template.
– Removed “Preliminary” on front page. All devices now final and in production.
– Section “Limitations” on page 36.
– Program example on page 49.
– Section “Overview” on page 122.
– Table 17-4 on page 135.
– Section “Limitations of debugWIRE” on page 140.
– Section “Serial Programming Algorithm” on page 151.
– Table 21-7 on page 166.
– EEPROM errata on pages 212, 212, 213, 214, and 215
– Ordering information on pages 204, 205, and 206.
28.5 Rev. 2586M-07/10
1. Clarified Section 6.4 “Clock Output Buffer” on page 31.
2. Added Ordering Codes -SN and -SNR for ATtiny25 extended temperature.
28.6 Rev. 2586L-06/10
1. Added:
– TSSOP for ATtiny45 in “Features” on page 1, Pinout Figure 1-1 on page 2, Ordering Information in
Section 25.2 “ATtiny45” on page 205, and Packaging Information in Section 26.4 “8X” on page 210
– Table 6-11, “Capacitance of Low-Frequency Crystal Oscillator,” on page 29
– Figure 22-36 on page 191 and Figure 22-37 on page 191, Typical Characteristics plots for Bandgap
Voltage vs. VCC and Temperature
– Extended temperature in Section 25.1 “ATtiny25” on page 204, Ordering Information
– Tape & reel part numbers in Ordering Information, in Section 25.1 “ATtiny25” on page 204 and Section
25.2 “ATtiny45” on page 205
1. “Bit 3 – FOC1B: Force Output Compare Match 1B” description in “GTCCR – General Timer/Counter1 Control
Register” on page 90 updated: PB3 in “compare match output pin PB3 (OC1B)” corrected to PB4.
1. Updated description of “EEARH – EEPROM Address Register” and “EEARL – EEPROM Address Register” on page
20.ATtiny25/45/85 [DATASHEET] 217
2586Q–AVR–08/2013
2. Updated:
– “Features” on page 1, removed Preliminary from ATtiny25
– Section 8.4.2 “Code Example” on page 44
– “PCMSK – Pin Change Mask Register” on page 52, Bit Descriptions
– “TCCR1 – Timer/Counter1 Control Register” on page 89 and “GTCCR – General Timer/Counter1
Control Register” on page 90, COM bit descriptions clarified
– Section 20.3.2 “Calibration Bytes” on page 150, frequencies (8 MHz, 6.4 MHz)
– Table 20-11, “Minimum Wait Delay Before Writing the Next Flash or EEPROM Location,” on page 153,
value for tWD_ERASE
– Table 20-16, “High-voltage Serial Programming Instruction Set for ATtiny25/45/85,” on page 158
– Table 21-1, “DC Characteristics. TA = -40°C to +85°C,” on page 161, notes adjusted
– Table 21-11, “Serial Programming Characteristics, TA = -40°C to +85°C, VCC = 1.8 - 5.5V (Unless
Otherwise Noted),” on page 170, added tSLIV
– Bit syntax throughout the datasheet, e.g. from CS02:0 to CS0[2:0].
28.7 Rev. 2586K-01/08
1. Updated Document Template.
2. Added Sections:
– “Data Retention” on page 6
– “Low Level Interrupt” on page 49
– “Device Signature Imprint Table” on page 149
3. Updated Sections:
– “Internal PLL for Fast Peripheral Clock Generation - clkPCK” on page 24
– “System Clock and Clock Options” on page 23
– “Internal PLL in ATtiny15 Compatibility Mode” on page 24
– “Sleep Modes” on page 34
– “Software BOD Disable” on page 35
– “External Interrupts” on page 49
– “Timer/Counter1 in PWM Mode” on page 97
– “USI – Universal Serial Interface” on page 108
– “Temperature Measurement” on page 133
– “Reading Lock, Fuse and Signature Data from Software” on page 143
– “Program And Data Memory Lock Bits” on page 147
– “Fuse Bytes” on page 148
– “Signature Bytes” on page 150
– “Calibration Bytes” on page 150
– “System and Reset Characteristics” on page 165
4. Added Figures:
– “Reset Pin Output Voltage vs. Sink Current (VCC = 3V)” on page 184
– “Reset Pin Output Voltage vs. Sink Current (VCC = 5V)” on page 185
– “Reset Pin Output Voltage vs. Source Current (VCC = 3V)” on page 185
– “Reset Pin Output Voltage vs. Source Current (VCC = 5V)” on page 186ATtiny25/45/85 [DATASHEET] 218
2586Q–AVR–08/2013
5. Updated Figure:
– “Reset Logic” on page 39
6. Updated Tables:
– “Start-up Times for Internal Calibrated RC Oscillator Clock” on page 28
– “Start-up Times for Internal Calibrated RC Oscillator Clock (in ATtiny15 Mode)” on page 28
– “Start-up Times for the 128 kHz Internal Oscillator” on page 28
– “Compare Mode Select in PWM Mode” on page 86
– “Compare Mode Select in PWM Mode” on page 98
– “DC Characteristics. TA = -40°C to +85°C” on page 161
– “Calibration Accuracy of Internal RC Oscillator” on page 164
– “ADC Characteristics” on page 167
7. Updated Code Example in Section:
– “Write” on page 17
8. Updated Bit Descriptions in:
– “MCUCR – MCU Control Register” on page 37
– “Bits 7:6 – COM0A[1:0]: Compare Match Output A Mode” on page 77
– “Bits 5:4 – COM0B[1:0]: Compare Match Output B Mode” on page 77
– “Bits 2:0 – ADTS[2:0]: ADC Auto Trigger Source” on page 138
– “SPMCSR – Store Program Memory Control and Status Register” on page 145.
9. Updated description of feature “EEPROM read may fail at low supply voltage / low clock frequency” in
Sections:
– “Errata ATtiny25” on page 212
– “Errata ATtiny45” on page 212
– “Errata ATtiny85” on page 215
10. Updated Package Description in Sections:
– “ATtiny25” on page 204
– “ATtiny45” on page 205
– “ATtiny85” on page 206
11. Updated Package Drawing:
– “S8S1” on page 209
12. Updated Order Codes for:
– “ATtiny25” on page 204
28.8 Rev. 2586J-12/06
1. Updated “Low Power Consumption” on page 1.
2. Updated description of instruction length in “Architectural Overview” .
3. Updated Flash size in “In-System Re-programmable Flash Program Memory” on
page 15.
4. Updated cross-references in sections “Atomic Byte Programming” , “Erase” and
“Write” , starting on page 17.
5. Updated “Atomic Byte Programming” on page 17.
6. Updated “Internal PLL for Fast Peripheral Clock Generation - clkPCK” on page 24.
7. Replaced single clocking system figure with two: Figure 6-2 and Figure 6-3.ATtiny25/45/85 [DATASHEET] 219
2586Q–AVR–08/2013
8. Updated Table 6-1 on page 25, Table 6-13 on page 30 and Table 6-6 on page 27.
9. Updated “Calibrated Internal Oscillator” on page 27.
10. Updated Table 6-5 on page 26.
11. Updated “OSCCAL – Oscillator Calibration Register” on page 31.
12. Updated “CLKPR – Clock Prescale Register” on page 32.
13. Updated “Power-down Mode” on page 35.
14. Updated “Bit 0” in “PRR – Power Reduction Register” on page 38.
15. Added footnote to Table 8-3 on page 46.
16. Updated Table 10-5 on page 63.
17. Deleted “Bits 7, 2” in “MCUCR – MCU Control Register” on page 64.
18. Updated and moved section “Timer/Counter0 Prescaler and Clock Sources”, now
located on page 66.
19. Updated “Timer/Counter1 Initialization for Asynchronous Mode” on page 86.
20. Updated bit description in “PLLCSR – PLL Control and Status Register” on page 94
and “PLLCSR – PLL Control and Status Register” on page 103.
21. Added recommended maximum frequency in“Prescaling and Conversion Timing” on
page 125.
22. Updated Figure 17-8 on page 129 .
23. Updated “Temperature Measurement” on page 133.
24. Updated Table 17-3 on page 134.
25. Updated bit R/W descriptions in:
“TIMSK – Timer/Counter Interrupt Mask Register” on page 81,
“TIFR – Timer/Counter Interrupt Flag Register” on page 81,
“TIMSK – Timer/Counter Interrupt Mask Register” on page 92,
“TIFR – Timer/Counter Interrupt Flag Register” on page 93,
“PLLCSR – PLL Control and Status Register” on page 94,
“TIMSK – Timer/Counter Interrupt Mask Register” on page 102,
“TIFR – Timer/Counter Interrupt Flag Register” on page 103,
“PLLCSR – PLL Control and Status Register” on page 103 and
“DIDR0 – Digital Input Disable Register 0” on page 138.
26. Added limitation to “Limitations of debugWIRE” on page 140.
27. Updated “DC Characteristics” on page 161.
28. Updated Table 21-7 on page 166.
29. Updated Figure 21-6 on page 171.
30. Updated Table 21-12 on page 171.
31. Updated Table 22-1 on page 177.
32. Updated Table 22-2 on page 177.
33. Updated Table 22-30, Table 22-31 and Table 22-32, starting on page 188.
34. Updated Table 22-33, Table 22-34 and Table 22-35, starting on page 189.
35. Updated Table 22-39 on page 192.
36. Updated Table 22-46, Table 22-47, Table 22-48 and Table 22-49.ATtiny25/45/85 [DATASHEET] 220
2586Q–AVR–08/2013
28.9 Rev. 2586I-09/06
28.10 Rev. 2586H-06/06
28.11 Rev. 2586G-05/06
28.12 Rev. 2586F-04/06
1. All Characterization data moved to “Electrical Characteristics” on page 161.
2. All Register Descriptions are gathered up in seperate sections in the end of each
chapter.
3. Updated Table 11-3 on page 78, Table 11-5 on page 79, Table 11-6 on page 80 and
Table 20-4 on page 148.
4. Updated “Calibrated Internal Oscillator” on page 27.
5. Updated Note in Table 7-1 on page 34.
6. Updated “System Control and Reset” on page 39.
7. Updated Register Description in “I/O Ports” on page 53.
8. Updated Features in “USI – Universal Serial Interface” on page 108.
9. Updated Code Example in “SPI Master Operation Example” on page 110 and “SPI
Slave Operation Example” on page 111.
10. Updated “Analog Comparator Multiplexed Input” on page 119.
11. Updated Figure 17-1 on page 123.
12. Updated “Signature Bytes” on page 150.
13. Updated “Electrical Characteristics” on page 161.
1. Updated “Calibrated Internal Oscillator” on page 27.
2. Updated Table 6.5.1 on page 31.
3. Added Table 21-2 on page 164.
1. Updated “Internal PLL for Fast Peripheral Clock Generation - clkPCK” on page 24.
2. Updated “Default Clock Source” on page 30.
3. Updated “Low-Frequency Crystal Oscillator” on page 29.
4. Updated “Calibrated Internal Oscillator” on page 27.
5. Updated “Clock Output Buffer” on page 31.
6. Updated “Power Management and Sleep Modes” on page 34.
7. Added “Software BOD Disable” on page 35.
8. Updated Figure 16-1 on page 119.
9. Updated “Bit 6 – ACBG: Analog Comparator Bandgap Select” on page 120.
10. Added note for Table 17-2 on page 125.
11. Updated “Register Summary” on page 200.
1. Updated “Digital Input Enable and Sleep Modes” on page 57.
2. Updated Table 20-16 on page 158.
3. Updated “Ordering Information” on page 204.ATtiny25/45/85 [DATASHEET] 221
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28.13 Rev. 2586E-03/06
28.14 Rev. 2586D-02/06
28.15 Rev. 2586C-06/05
28.16 Rev. 2586B-05/05
28.17 Rev. 2586A-02/05
Initial revision.
1. Updated Features in “Analog to Digital Converter” on page 122.
2. Updated Operation in “Analog to Digital Converter” on page 122.
3. Updated Table 17-2 on page 133.
4. Updated Table