APPLICATION NOTE AT09280: ASF Manual (SAM D10) ASF PROGRAMMERS MANUAL Preface The Atmel# Software Framework (ASF) is a collection of free embedded software for Atmel microcontroller devices. It simplifies the usage of Atmel products, providing an abstraction to the hardware and high-value middleware. ASF is designed to be used for evaluation, prototyping, design and production phases. ASF is integrated in the Atmel Studio IDE with a graphical user interface or available as a standalone package for several commercial and open source compilers. This document describes the API interfaces to the low level ASF module drivers of the device. For more information on ASF refer to the online documentation at www.atmel.com/ asf. 42359A-SAMD10-01/2015 Table of Contents Preface ................................................................................................ 1 Software License .............................................................................. 12 1. SAM Analog Comparator Driver (AC) ........................................ 13 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 1.7. 1.8. Prerequisites ............................................................................ Module Overview ...................................................................... 1.2.1. Driver Feature Macro Definition ....................................... 1.2.2. Window Comparators and Comparator Pairs ...................... 1.2.3. Positive and Negative Input MUXs ................................... 1.2.4. Output Filtering ............................................................. 1.2.5. Input Hysteresis ............................................................ 1.2.6. Single Shot and Continuous Sampling Modes ..................... 1.2.7. Events ........................................................................ 1.2.8. Physical Connection ...................................................... Special Considerations ............................................................... Extra Information ....................................................................... Examples ................................................................................. API Overview ........................................................................... 1.6.1. Variable and Type Definitions .......................................... 1.6.2. Structure Definitions ...................................................... 1.6.3. Macro Definitions .......................................................... 1.6.4. Function Definitions ....................................................... 1.6.5. Enumeration Definitions .................................................. Extra Information for AC Driver .................................................... 1.7.1. Acronyms .................................................................... 1.7.2. Dependencies .............................................................. 1.7.3. Errata ......................................................................... 1.7.4. Module History ............................................................. Examples for AC Driver .............................................................. 13 13 13 14 14 14 14 14 14 15 15 15 16 16 16 16 18 19 29 32 32 32 32 32 32 2. SAM Analog to Digital Converter Driver (ADC) .......................... 33 2.1. 2.2. 2.3. 2.4. 2.5. 2.6. 2.7. 2.8. Prerequisites ............................................................................ Module Overview ...................................................................... 2.2.1. Sample Clock Prescaler ................................................. 2.2.2. ADC Resolution ............................................................ 2.2.3. Conversion Modes ........................................................ 2.2.4. Differential and Single-Ended Conversion .......................... 2.2.5. Sample Time ................................................................ 2.2.6. Averaging .................................................................... 2.2.7. Offset and Gain Correction ............................................. 2.2.8. Pin Scan ..................................................................... 2.2.9. Window Monitor ............................................................ 2.2.10. Events ........................................................................ Special Considerations ............................................................... Extra Information ....................................................................... Examples ................................................................................. API Overview ........................................................................... 2.6.1. Structure Definitions ...................................................... 2.6.2. Macro Definitions .......................................................... 2.6.3. Function Definitions ....................................................... 2.6.4. Enumeration Definitions .................................................. Extra Information for ADC Driver .................................................. 2.7.1. Acronyms .................................................................... 2.7.2. Dependencies .............................................................. 2.7.3. Errata ......................................................................... 2.7.4. Module History ............................................................. Examples for ADC Driver ............................................................ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 2 33 33 34 34 34 34 34 35 35 36 36 36 36 36 37 37 37 39 40 51 56 56 56 56 56 57 3. SAM Brown Out Detector Driver (BOD) ..................................... 58 3.1. 3.2. 3.3. 3.4. 3.5. 3.6. 3.7. 3.8. Prerequisites ............................................................................ Module Overview ...................................................................... Special Considerations ............................................................... Extra Information ....................................................................... Examples ................................................................................. API Overview ........................................................................... 3.6.1. Structure Definitions ...................................................... 3.6.2. Function Definitions ....................................................... 3.6.3. Enumeration Definitions .................................................. Extra Information for BOD Driver .................................................. 3.7.1. Acronyms .................................................................... 3.7.2. Dependencies .............................................................. 3.7.3. Errata ......................................................................... 3.7.4. Module History ............................................................. Examples for BOD Driver ........................................................... 3.8.1. Application Use Case for BOD - Application ....................... 58 58 58 58 59 59 59 59 62 63 63 63 63 63 63 64 4. SAM Digital-to-Analog Driver (DAC) .......................................... 65 4.1. 4.2. 4.3. 4.4. 4.5. 4.6. 4.7. 4.8. Prerequisites ............................................................................ Module Overview ...................................................................... 4.2.1. Conversion Range ........................................................ 4.2.2. Conversion .................................................................. 4.2.3. Analog Output .............................................................. 4.2.4. Events ........................................................................ 4.2.5. Left and Right Adjusted Values ........................................ 4.2.6. Clock Sources .............................................................. Special Considerations ............................................................... 4.3.1. Output Driver ............................................................... 4.3.2. Conversion Time ........................................................... Extra Information ....................................................................... Examples ................................................................................. API Overview ........................................................................... 4.6.1. Variable and Type Definitions .......................................... 4.6.2. Structure Definitions ...................................................... 4.6.3. Macro Definitions .......................................................... 4.6.4. Function Definitions ....................................................... 4.6.5. Enumeration Definitions .................................................. Extra Information for DAC Driver .................................................. 4.7.1. Acronyms .................................................................... 4.7.2. Dependencies .............................................................. 4.7.3. Errata ......................................................................... 4.7.4. Module History ............................................................. Examples for DAC Driver ............................................................ 4.8.1. Quick Start Guide for DAC - Basic ................................... 4.8.2. Quick Start Guide for DAC - Callback ............................... 4.8.3. Quick Start Guide for Using DMA with ADC/DAC ................. 65 65 66 66 66 67 67 67 67 67 68 68 68 68 68 68 69 69 82 83 83 83 83 83 84 84 86 93 5. SAM Direct Memory Access Controller Driver (DMAC) .............. 94 5.1. 5.2. 5.3. 5.4. 5.5. Prerequisites ............................................................................ Module Overview ...................................................................... 5.2.1. Driver Feature Macro Definition ....................................... 5.2.2. Terminology Used in DMAC Transfers ............................... 5.2.3. DMA Channels ............................................................. 5.2.4. DMA Triggers ............................................................... 5.2.5. DMA Transfer Descriptor ................................................ 5.2.6. DMA Interrupts/Events ................................................... Special Considerations ............................................................... Extra Information ....................................................................... Examples ................................................................................. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 3 94 94 95 95 96 96 96 96 96 97 97 5.6. 5.7. 5.8. API Overview ........................................................................... 97 5.6.1. Variable and Type Definitions .......................................... 97 5.6.2. Structure Definitions ...................................................... 97 5.6.3. Macro Definitions .......................................................... 99 5.6.4. Function Definitions ....................................................... 99 5.6.5. Enumeration Definitions ................................................ 106 Extra Information for DMAC Driver .............................................. 109 5.7.1. Acronyms ................................................................... 109 5.7.2. Dependencies ............................................................. 109 5.7.3. Errata ........................................................................ 109 5.7.4. Module History ............................................................ 109 Examples for DMAC Driver ....................................................... 109 5.8.1. Quick Start Guide for Memory to Memory Data Transfer Using DMAC .............................................................. 109 6. SAM EEPROM Emulator Service (EEPROM) .......................... 114 6.1. 6.2. 6.3. 6.4. 6.5. 6.6. 6.7. 6.8. Prerequisites ........................................................................... Module Overview ..................................................................... 6.2.1. Implementation Details ................................................. 6.2.2. Memory Layout ........................................................... Special Considerations ............................................................. 6.3.1. NVM Controller Configuration ........................................ 6.3.2. Logical EEPROM Page Size .......................................... 6.3.3. Committing of the Write Cache ...................................... Extra Information ..................................................................... Examples ............................................................................... API Overview .......................................................................... 6.6.1. Structure Definitions ..................................................... 6.6.2. Macro Definitions ........................................................ 6.6.3. Function Definitions ..................................................... Extra Information ..................................................................... 6.7.1. Acronyms ................................................................... 6.7.2. Dependencies ............................................................. 6.7.3. Errata ........................................................................ 6.7.4. Module History ............................................................ Examples for Emulated EEPROM Service .................................... 6.8.1. Quick Start Guide for the Emulated EEPROM Module Basic Use Case .......................................................... 114 114 115 116 118 118 118 118 118 118 118 118 119 120 124 124 124 124 124 124 124 7. SAM Event System Driver (EVENTS) ...................................... 127 7.1. 7.2. 7.3. 7.4. 7.5. 7.6. 7.7. Prerequisites ........................................................................... Module Overview ..................................................................... 7.2.1. Event Channels .......................................................... 7.2.2. Event Users ............................................................... 7.2.3. Edge Detection ........................................................... 7.2.4. Path Selection ............................................................ 7.2.5. Physical Connection ..................................................... 7.2.6. Configuring Events ...................................................... Special Considerations ............................................................. Extra Information ..................................................................... Examples ............................................................................... API Overview .......................................................................... 7.6.1. Variable and Type Definitions ......................................... 7.6.2. Structure Definitions ..................................................... 7.6.3. Macro Definitions ........................................................ 7.6.4. Function Definitions ..................................................... 7.6.5. Enumeration Definitions ................................................ Extra Information for EVENTS Driver ........................................... 7.7.1. Acronyms ................................................................... 7.7.2. Dependencies ............................................................. 7.7.3. Errata ........................................................................ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 4 127 127 128 128 128 128 129 130 130 130 130 130 130 131 131 131 140 141 141 141 141 7.8. 7.7.4. Module History ............................................................ 141 Examples for EVENTS Driver .................................................... 141 8. SAM External Interrupt Driver (EXTINT) .................................. 142 8.1. 8.2. 8.3. 8.4. 8.5. 8.6. 8.7. 8.8. Prerequisites ........................................................................... Module Overview ..................................................................... 8.2.1. Logical Channels ......................................................... 8.2.2. NMI Channels ............................................................. 8.2.3. Input Filtering and Detection .......................................... 8.2.4. Events and Interrupts ................................................... 8.2.5. Physical Connection ..................................................... Special Considerations ............................................................. Extra Information ..................................................................... Examples ............................................................................... API Overview .......................................................................... 8.6.1. Variable and Type Definitions ......................................... 8.6.2. Structure Definitions ..................................................... 8.6.3. Macro Definitions ........................................................ 8.6.4. Function Definitions ..................................................... 8.6.5. Enumeration Definitions ................................................ Extra Information for EXTINT Driver ............................................ 8.7.1. Acronyms ................................................................... 8.7.2. Dependencies ............................................................. 8.7.3. Errata ........................................................................ 8.7.4. Module History ............................................................ Examples for EXTINT Driver ...................................................... 8.8.1. Quick Start Guide for EXTINT - Basic .............................. 8.8.2. Quick Start Guide for EXTINT - Callback .......................... 142 142 142 143 143 143 143 144 144 144 144 144 144 145 146 153 154 154 154 154 154 155 155 157 9. SAM I2C Driver (SERCOM I2C) .............................................. 160 9.1. 9.2. 9.3. 9.4. 9.5. 9.6. 9.7. 9.8. Prerequisites ........................................................................... 160 Module Overview ..................................................................... 160 9.2.1. Driver Feature Macro Definition ...................................... 161 9.2.2. Functional Description .................................................. 161 9.2.3. Bus Topology .............................................................. 161 9.2.4. Transactions ............................................................... 161 9.2.5. Multi Master ............................................................... 163 9.2.6. Bus States ................................................................. 163 9.2.7. Bus Timing ................................................................. 164 9.2.8. Operation in Sleep Modes ............................................. 164 Special Considerations ............................................................. 165 9.3.1. Interrupt-driven Operation ............................................. 165 Extra Information ..................................................................... 165 Examples ............................................................................... 165 API Overview .......................................................................... 165 9.6.1. Structure Definitions ..................................................... 165 9.6.2. Macro Definitions ........................................................ 167 9.6.3. Function Definitions ..................................................... 169 9.6.4. Enumeration Definitions ................................................ 192 Extra Information for SERCOM I2C Driver .................................... 195 9.7.1. Acronyms ................................................................... 195 9.7.2. Dependencies ............................................................. 195 9.7.3. Errata ........................................................................ 195 9.7.4. Module History ............................................................ 195 Examples for SERCOM I2C Driver .............................................. 196 9.8.1. Quick Start Guide for SERCOM I2C Master - Basic ............ 196 9.8.2. Quick Start Guide for SERCOM I2C Master - Callback ........ 199 9.8.3. Quick Start Guide for Using DMA with SERCOM I2C Master ....................................................................... 203 9.8.4. Quick Start Guide for SERCOM I2C Slave - Basic .............. 207 9.8.5. Quick Start Guide for SERCOM I2C Slave - Callback .......... 210 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 5 9.8.6. Quick Start Guide for Using DMA with SERCOM I2C Slave .. 213 10. SAM Non-Volatile Memory Driver (NVM) ................................. 218 10.1. Prerequisites ........................................................................... 10.2. Module Overview ..................................................................... 10.2.1. Driver Feature Macro Definition ...................................... 10.2.2. Memory Regions ......................................................... 10.2.3. Region Lock Bits ......................................................... 10.2.4. Read/Write ................................................................. 10.3. Special Considerations ............................................................. 10.3.1. Page Erasure ............................................................. 10.3.2. Clocks ....................................................................... 10.3.3. Security Bit ................................................................ 10.4. Extra Information ..................................................................... 10.5. Examples ............................................................................... 10.6. API Overview .......................................................................... 10.6.1. Structure Definitions ..................................................... 10.6.2. Function Definitions ..................................................... 10.6.3. Enumeration Definitions ................................................ 10.7. Extra Information for NVM Driver ................................................ 10.7.1. Acronyms ................................................................... 10.7.2. Dependencies ............................................................. 10.7.3. Errata ........................................................................ 10.7.4. Module History ............................................................ 10.8. Examples for NVM Driver .......................................................... 10.8.1. Quick Start Guide for NVM - Basic ................................. 218 218 218 218 219 220 220 220 220 220 220 220 221 221 222 229 232 232 232 233 233 233 233 11. SAM Peripheral Access Controller Driver (PAC) ...................... 237 11.1. Prerequisites ........................................................................... 11.2. Module Overview ..................................................................... 11.2.1. Locking Scheme ......................................................... 11.2.2. Recommended Implementation ...................................... 11.2.3. Why Disable Interrupts ................................................. 11.2.4. Run-away Code .......................................................... 11.2.5. Faulty Module Pointer .................................................. 11.2.6. Use of __no_inline ....................................................... 11.2.7. Physical Connection ..................................................... 11.3. Special Considerations ............................................................. 11.3.1. Non-Writable Registers ................................................. 11.3.2. Reading Lock State ..................................................... 11.4. Extra Information ..................................................................... 11.5. Examples ............................................................................... 11.6. API Overview .......................................................................... 11.6.1. Macro Definitions ........................................................ 11.6.2. Function Definitions ..................................................... 11.7. List of Non-Write Protected Registers .......................................... 11.8. Extra Information for PAC Driver ................................................. 11.8.1. Acronyms ................................................................... 11.8.2. Dependencies ............................................................. 11.8.3. Errata ........................................................................ 11.8.4. Module History ............................................................ 11.9. Examples for PAC Driver .......................................................... 237 237 237 238 238 239 241 242 242 242 242 242 243 243 243 243 244 245 246 246 247 247 247 247 12. SAM Port Driver (PORT) .......................................................... 248 12.1. Prerequisites ........................................................................... 12.2. Module Overview ..................................................................... 12.2.1. Driver Feature Macro Definition ...................................... 12.2.2. Physical and Logical GPIO Pins ..................................... 12.2.3. Physical Connection ..................................................... 12.3. Special Considerations ............................................................. 12.4. Extra Information ..................................................................... AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 6 248 248 248 248 249 249 249 12.5. Examples ............................................................................... 12.6. API Overview .......................................................................... 12.6.1. Structure Definitions ..................................................... 12.6.2. Macro Definitions ........................................................ 12.6.3. Function Definitions ..................................................... 12.6.4. Enumeration Definitions ................................................ 12.7. Extra Information for PORT Driver .............................................. 12.7.1. Acronyms ................................................................... 12.7.2. Dependencies ............................................................. 12.7.3. Errata ........................................................................ 12.7.4. Module History ............................................................ 12.8. Examples for PORT Driver ........................................................ 12.8.1. Quick Start Guide for PORT - Basic ................................ 249 249 249 250 250 255 255 255 256 256 256 256 256 13. SAM RTC Calendar Driver (RTC CAL) .................................... 259 13.1. Prerequisites ........................................................................... 13.2. Module Overview ..................................................................... 13.2.1. Driver Feature Macro Definition ...................................... 13.2.2. Alarms and Overflow .................................................... 13.2.3. Periodic Events ........................................................... 13.2.4. Digital Frequency Correction .......................................... 13.3. Special Considerations ............................................................. 13.3.1. Year Limit .................................................................. 13.3.2. Clock Setup ............................................................... 13.4. Extra Information ..................................................................... 13.5. Examples ............................................................................... 13.6. API Overview .......................................................................... 13.6.1. Structure Definitions ..................................................... 13.6.2. Macro Definitions ........................................................ 13.6.3. Function Definitions ..................................................... 13.6.4. Enumeration Definitions ................................................ 13.7. Extra Information for RTC (CAL) Driver ........................................ 13.7.1. Acronyms ................................................................... 13.7.2. Dependencies ............................................................. 13.7.3. Errata ........................................................................ 13.7.4. Module History ............................................................ 13.8. Examples for RTC CAL Driver ................................................... 13.8.1. Quick Start Guide for RTC (CAL) - Basic .......................... 13.8.2. Quick Start Guide for RTC (CAL) - Callback ...................... 259 259 260 260 260 261 261 261 261 262 262 262 262 264 264 274 275 275 275 275 276 276 276 279 14. SAM RTC Count Driver (RTC COUNT) ................................... 284 14.1. Prerequisites ........................................................................... 14.2. Module Overview ..................................................................... 14.2.1. Driver Feature Macro Definition ...................................... 14.3. Compare and Overflow ............................................................. 14.3.1. Periodic Events ........................................................... 14.3.2. Digital Frequency Correction .......................................... 14.4. Special Considerations ............................................................. 14.4.1. Clock Setup ............................................................... 14.5. Extra Information ..................................................................... 14.6. Examples ............................................................................... 14.7. API Overview .......................................................................... 14.7.1. Structure Definitions ..................................................... 14.7.2. Macro Definitions ........................................................ 14.7.3. Function Definitions ..................................................... 14.7.4. Enumeration Definitions ................................................ 14.8. Extra Information for RTC COUNT Driver ..................................... 14.8.1. Acronyms ................................................................... 14.8.2. Dependencies ............................................................. 14.8.3. Errata ........................................................................ 14.8.4. Module History ............................................................ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 7 284 284 285 285 285 286 286 286 287 287 287 287 288 288 299 300 300 300 300 300 14.9. Examples for RTC (COUNT) Driver ............................................. 301 15. SAM Serial Peripheral Interface Driver (SERCOM SPI) ........... 302 15.1. Prerequisites ........................................................................... 302 15.2. Module Overview ..................................................................... 302 15.2.1. Driver Feature Macro Definition ...................................... 302 15.2.2. SPI Bus Connection ..................................................... 303 15.2.3. SPI Character Size ...................................................... 303 15.2.4. Master Mode .............................................................. 304 15.2.5. Slave Mode ................................................................ 304 15.2.6. Data Modes ............................................................... 304 15.2.7. SERCOM Pads ........................................................... 304 15.2.8. Operation in Sleep Modes ............................................. 305 15.2.9. Clock Generation ........................................................ 305 15.3. Special Considerations ............................................................. 305 15.3.1. pinmux Settings .......................................................... 305 15.4. Extra Information ..................................................................... 305 15.5. Examples ............................................................................... 305 15.6. API Overview .......................................................................... 305 15.6.1. Variable and Type Definitions ......................................... 305 15.6.2. Structure Definitions ..................................................... 306 15.6.3. Macro Definitions ........................................................ 307 15.6.4. Function Definitions ..................................................... 309 15.6.5. Enumeration Definitions ................................................ 325 15.7. MUX Settings ......................................................................... 328 15.7.1. Master Mode Settings .................................................. 328 15.7.2. Slave Mode Settings .................................................... 329 15.8. Extra Information for SERCOM SPI Driver .................................... 329 15.8.1. Acronyms ................................................................... 329 15.8.2. Dependencies ............................................................. 330 15.8.3. Workarounds Implemented by Driver ............................... 330 15.8.4. Module History ............................................................ 330 15.9. Examples for SERCOM SPI Driver ............................................. 330 15.9.1. Quick Start Guide for SERCOM SPI Master - Polled ........... 330 15.9.2. Quick Start Guide for SERCOM SPI Slave - Polled ............. 334 15.9.3. Quick Start Guide for SERCOM SPI Master - Callback ........ 337 15.9.4. Quick Start Guide for SERCOM SPI Slave - Callback .......... 341 15.9.5. Quick Start Guide for Using DMA with SERCOM SPI .......... 345 16. SAM Serial USART Driver (SERCOM USART) ....................... 355 16.1. Prerequisites ........................................................................... 16.2. Module Overview ..................................................................... 16.2.1. Driver Feature Macro Definition ...................................... 16.2.2. Frame Format ............................................................. 16.2.3. Synchronous Mode ...................................................... 16.2.4. Asynchronous Mode .................................................... 16.2.5. Parity ........................................................................ 16.2.6. GPIO Configuration ...................................................... 16.3. Special Considerations ............................................................. 16.4. Extra Information ..................................................................... 16.5. Examples ............................................................................... 16.6. API Overview .......................................................................... 16.6.1. Variable and Type Definitions ......................................... 16.6.2. Structure Definitions ..................................................... 16.6.3. Macro Definitions ........................................................ 16.6.4. Function Definitions ..................................................... 16.6.5. Enumeration Definitions ................................................ 16.7. SERCOM USART MUX Settings ................................................ 16.8. Extra Information for SERCOM USART Driver ............................... 16.8.1. Acronyms ................................................................... 16.8.2. Dependencies ............................................................. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 8 355 355 355 356 356 356 357 357 357 357 357 357 357 358 359 359 371 373 374 374 374 16.8.3. Errata ........................................................................ 16.8.4. Module History ............................................................ 16.9. Examples for SERCOM USART Driver ........................................ 16.9.1. Quick Start Guide for SERCOM USART - Basic ................. 16.9.2. Quick Start Guide for SERCOM USART - Callback ............. 16.9.3. Quick Start Guide for Using DMA with SERCOM USART ..... 374 374 375 375 378 381 17. SAM System Clock Management Driver (SYSTEM CLOCK) ... 388 17.1. Prerequisites ........................................................................... 388 17.2. Module Overview ..................................................................... 388 17.2.1. Driver Feature Macro Definition ...................................... 388 17.2.2. Clock Sources ............................................................ 389 17.2.3. CPU / Bus Clocks ........................................................ 389 17.2.4. Clock Masking ............................................................ 389 17.2.5. Generic Clocks ........................................................... 389 17.3. Special Considerations ............................................................. 391 17.4. Extra Information ..................................................................... 391 17.5. Examples ............................................................................... 391 17.6. API Overview .......................................................................... 391 17.6.1. Structure Definitions ..................................................... 391 17.6.2. Function Definitions ..................................................... 394 17.6.3. Enumeration Definitions ................................................ 408 17.7. Extra Information for SYSTEM CLOCK Driver ............................... 414 17.7.1. Acronyms ................................................................... 414 17.7.2. Dependencies ............................................................. 414 17.7.3. Errata ........................................................................ 414 17.7.4. Module History ............................................................ 414 17.8. Examples for System Clock Driver .............................................. 415 18. SAM System Driver (SYSTEM) ................................................ 416 18.1. Prerequisites ........................................................................... 18.2. Module Overview ..................................................................... 18.2.1. Voltage References ...................................................... 18.2.2. System Reset Cause ................................................... 18.2.3. Sleep Modes .............................................................. 18.3. Special Considerations ............................................................. 18.4. Extra Information ..................................................................... 18.5. Examples ............................................................................... 18.6. API Overview .......................................................................... 18.6.1. Function Definitions ..................................................... 18.6.2. Enumeration Definitions ................................................ 18.7. Extra Information for SYSTEM Driver .......................................... 18.7.1. Acronyms ................................................................... 18.7.2. Dependencies ............................................................. 18.7.3. Errata ........................................................................ 18.7.4. Module History ............................................................ 416 416 416 417 417 417 417 417 417 417 420 421 421 421 421 421 19. SAM System Interrupt Driver (SYSTEM INTERRUPT) ............ 422 19.1. Prerequisites ........................................................................... 19.2. Module Overview ..................................................................... 19.2.1. Critical Sections .......................................................... 19.2.2. Software Interrupts ...................................................... 19.3. Special Considerations ............................................................. 19.4. Extra Information ..................................................................... 19.5. Examples ............................................................................... 19.6. API Overview .......................................................................... 19.6.1. Function Definitions ..................................................... 19.6.2. Enumeration Definitions ................................................ 19.7. Extra Information for SYSTEM INTERRUPT Driver ......................... 19.7.1. Acronyms ................................................................... 19.7.2. Dependencies ............................................................. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 9 422 422 422 422 423 423 423 423 423 428 429 429 429 19.7.3. Errata ........................................................................ 430 19.7.4. Module History ............................................................ 430 19.8. Examples for SYSTEM INTERRUPT Driver .................................. 430 20. SAM System Pin Multiplexer Driver (SYSTEM PINMUX) ......... 431 20.1. Prerequisites ........................................................................... 431 20.2. Module Overview ..................................................................... 431 20.2.1. Driver Feature Macro Definition ...................................... 431 20.2.2. Physical and Logical GPIO Pins ..................................... 431 20.2.3. Peripheral Multiplexing ................................................. 432 20.2.4. Special Pad Characteristics ........................................... 432 20.2.5. Physical Connection ..................................................... 432 20.3. Special Considerations ............................................................. 432 20.4. Extra Information ..................................................................... 433 20.5. Examples ............................................................................... 433 20.6. API Overview .......................................................................... 433 20.6.1. Structure Definitions ..................................................... 433 20.6.2. Macro Definitions ........................................................ 433 20.6.3. Function Definitions ..................................................... 433 20.6.4. Enumeration Definitions ................................................ 436 20.7. Extra Information for SYSTEM PINMUX Driver .............................. 437 20.7.1. Acronyms ................................................................... 437 20.7.2. Dependencies ............................................................. 437 20.7.3. Errata ........................................................................ 437 20.7.4. Module History ............................................................ 437 20.8. Examples for SYSTEM PINMUX Driver ....................................... 438 20.8.1. Quick Start Guide for SYSTEM PINMUX - Basic ................ 438 21. SAM Timer Counter for Control Applications Driver (TCC) ....... 440 21.1. Prerequisites ........................................................................... 440 21.2. Module Overview ..................................................................... 440 21.2.1. Functional Description .................................................. 441 21.2.2. Base Timer/Counter ..................................................... 442 21.2.3. Capture Operations ...................................................... 443 21.2.4. Compare Match Operation ............................................ 444 21.2.5. Waveform Extended Controls ........................................ 445 21.2.6. Double and Circular Buffering ........................................ 446 21.2.7. Sleep Mode ................................................................ 447 21.3. Special Considerations ............................................................. 447 21.3.1. Module Features ......................................................... 447 21.3.2. Channels vs. Pin outs .................................................. 447 21.4. Extra Information ..................................................................... 447 21.5. Examples ............................................................................... 448 21.6. API Overview .......................................................................... 448 21.6.1. Variable and Type Definitions ......................................... 448 21.6.2. Structure Definitions ..................................................... 448 21.6.3. Macro Definitions ........................................................ 453 21.6.4. Function Definitions ..................................................... 456 21.6.5. Enumeration Definitions ................................................ 471 21.7. Extra Information for TCC Driver ................................................ 479 21.7.1. Acronyms ................................................................... 479 21.7.2. Dependencies ............................................................. 480 21.7.3. Errata ........................................................................ 480 21.7.4. Module History ............................................................ 480 21.8. Examples for TCC Driver .......................................................... 480 21.8.1. Quick Start Guide for TCC - Basic .................................. 480 21.8.2. Quick Start Guide for TCC - Double Buffering and Circular ... 483 21.8.3. Quick Start Guide for TCC - Timer .................................. 487 21.8.4. Quick Start Guide for TCC - Callback .............................. 490 21.8.5. Quick Start Guide for TCC - Non-Recoverable Fault ........... 494 21.8.6. Quick Start Guide for TCC - Recoverable Fault ................. 502 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 10 21.8.7. Quick Start Guide for Using DMA with TCC ...................... 510 22. SAM Timer/Counter Driver (TC) ............................................... 521 22.1. Prerequisites ........................................................................... 22.2. Module Overview ..................................................................... 22.2.1. Driver Feature Macro Definition ...................................... 22.2.2. Functional Description .................................................. 22.2.3. Timer/Counter Size ...................................................... 22.2.4. Clock Settings ............................................................ 22.2.5. Compare Match Operations ........................................... 22.2.6. One-shot Mode ........................................................... 22.3. Special Considerations ............................................................. 22.4. Extra Information ..................................................................... 22.5. Examples ............................................................................... 22.6. API Overview .......................................................................... 22.6.1. Variable and Type Definitions ......................................... 22.6.2. Structure Definitions ..................................................... 22.6.3. Macro Definitions ........................................................ 22.6.4. Function Definitions ..................................................... 22.6.5. Enumeration Definitions ................................................ 22.7. Extra Information for TC Driver .................................................. 22.7.1. Acronyms ................................................................... 22.7.2. Dependencies ............................................................. 22.7.3. Errata ........................................................................ 22.7.4. Module History ............................................................ 22.8. Examples for TC Driver ............................................................ 521 521 522 522 523 523 524 526 526 526 526 526 526 526 529 532 541 544 544 544 544 544 544 23. SAM Watchdog Driver (WDT) .................................................. 546 23.1. Prerequisites ........................................................................... 23.2. Module Overview ..................................................................... 23.2.1. Locked Mode .............................................................. 23.2.2. Window Mode ............................................................. 23.2.3. Early Warning ............................................................. 23.2.4. Physical Connection ..................................................... 23.3. Special Considerations ............................................................. 23.4. Extra Information ..................................................................... 23.5. Examples ............................................................................... 23.6. API Overview .......................................................................... 23.6.1. Variable and Type Definitions ......................................... 23.6.2. Structure Definitions ..................................................... 23.6.3. Function Definitions ..................................................... 23.6.4. Enumeration Definitions ................................................ 23.7. Extra Information for WDT Driver ................................................ 23.7.1. Acronyms ................................................................... 23.7.2. Dependencies ............................................................. 23.7.3. Errata ........................................................................ 23.7.4. Module History ............................................................ 23.8. Examples for WDT Driver ......................................................... 23.8.1. Quick Start Guide for WDT - Basic ................................. 23.8.2. Quick Start Guide for WDT - Callback ............................. 546 546 547 547 547 547 547 547 548 548 548 548 548 553 554 554 554 554 554 554 555 557 24. Examples for Power Driver ...................................................... 560 Index ............................................................................................... 561 Document Revision History ............................................................ 569 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 11 Software License Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of Atmel may not be used to endorse or promote products derived from this software without specific prior written permission. 4. This software may only be redistributed and used in connection with an Atmel microcontroller product. THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 12 1. SAM Analog Comparator Driver (AC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Analog Comparator functionality, for the comparison of analog voltages against a known reference voltage to determine its relative level. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● AC (Analog Comparator) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 1.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 1.2 Module Overview The Analog Comparator module provides an interface for the comparison of one or more analog voltage inputs (sourced from external or internal inputs) against a known reference voltage, to determine if the unknown voltage is higher or lower than the reference. Additionally, window functions are provided so that two comparators can be connected together to determine if an input is below, inside, above, or outside the two reference points of the window. Each comparator requires two analog input voltages, a positive and negative channel input. The result of the comparison is a binary true if the comparator's positive channel input is higher than the comparator's negative input channel, and false if otherwise. 1.2.1 Driver Feature Macro Definition 1 Driver Feature Macro Supported devices FEATURE_AC_HYSTERESIS_LEVEL SAML21 FEATURE_AC_SYNCBUSY_SCHEME_VERSION_2 SAML21 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 13 Driver Feature Macro Supported devices FEATURE_AC_RUN_IN_STANDY_EACH_COMPARATOR SAML21 FEATURE_AC_RUN_IN_STANDY_PAIR_COMPARATORSAMD20/D21/D10/D11/R21 Note 1.2.2 The specific features are only available in the driver when the selected device supports those features. Window Comparators and Comparator Pairs Each comparator module contains one or more comparator pairs, a set of two distinct comparators which can be used independently or linked together for Window Comparator mode. In this latter mode, the two comparator units in a comparator pair are linked together to allow the module to detect if an input voltage is below, inside, above, or outside a window set by the upper and lower threshold voltages set by the two comparators. If not required, window comparison mode can be turned off and the two comparator units can be configured and used separately. 1.2.3 Positive and Negative Input MUXs Each comparator unit requires two input voltages, a positive and a negative channel (note that these names refer to the logical operation that the unit performs, and both voltages should be above GND), which are then compared with one another. Both the positive and the negative channel inputs are connected to a pair of MUXs, which allows one of several possible inputs to be selected for each comparator channel. The exact channels available for each comparator differ for the positive and the negative inputs, but the same MUX choices are available for all comparator units (i.e. all positive MUXes are identical, all negative MUXes are identical). This allows the user application to select which voltages are compared to one another. When used in window mode, both comparators in the window pair should have their positive channel input MUXs configured to the same input channel, with the negative channel input MUXs used to set the lower and upper window bounds. 1.2.4 Output Filtering The output of each comparator unit can either be used directly with no filtering (giving a lower latency signal, with potentially more noise around the comparison threshold) or be passed through a multiple stage digital majority filter. Several filter lengths are available, with the longer stages producing a more stable result, at the expense of a higher latency. When output filtering is used in single shot mode, a single trigger of the comparator will automatically perform the required number of samples to produce a correctly filtered result. 1.2.5 Input Hysteresis To prevent unwanted noise around the threshold where the comparator unit's positive and negative input channels are close in voltage to one another, an optional hysteresis can be used to widen the point at which the output result flips. This mode will prevent a change in the comparison output unless the inputs cross one another beyond the hysteresis gap introduces by this mode. 1.2.6 Single Shot and Continuous Sampling Modes Comparators can be configured to run in either Single Shot or Continuous sampling modes; when in Single Shot mode, the comparator will only perform a comparison (and any resulting filtering, see Output Filtering) when triggered via a software or event trigger. This mode improves the power efficiency of the system by only performing comparisons when actually required by the application. For systems requiring a lower latency or more frequent comparisons, continuous mode will place the comparator into continuous sampling mode, which increases the module's power consumption, but decreases the latency between each comparison result by automatically performing a comparison on every cycle of the module's clock. 1.2.7 Events Each comparator unit is capable of being triggered by both software and hardware triggers. Hardware input events allow for other peripherals to automatically trigger a comparison on demand - for example, a timer output event could be used to trigger comparisons at a desired regular interval. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 14 The module's output events can similarly be used to trigger other hardware modules each time a new comparison result is available. This scheme allows for reduced levels of CPU usage in an application and lowers the overall system response latency by directly triggering hardware peripherals from one another without requiring software intervention. Note 1.2.8 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Physical Connection Physically, the modules are interconnected within the device as shown in Figure 1-1: Physical Connection on page 15. Figure 1-1. Physical Connection GP IO P in s + GP IO P in s AC 1 In t e r n a l DAC Co m p a r a t o r 1 Re s u lt - In t e r n a l Re fs Win d o w Lo g ic GP IO P in s In t e r n a l DAC Win d o w Re s u lt AC 2 Co m p a r a t o r 2 Re s u lt In t e r n a l Re fs + GP IO P in s 1.3 Special Considerations The number of comparator pairs (and, thus, window comparators) within a single hardware instance of the Analog Comparator module is device-specific. Some devices will contain a single comparator pair, while others may have two pairs; refer to your device specific datasheet for details. 1.4 Extra Information For extra information, see Extra Information for AC Driver. This includes: ● Acronyms ● Dependencies ● Errata ● Module History AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 15 1.5 Examples For a list of examples related to this driver, see Examples for AC Driver. 1.6 API Overview 1.6.1 Variable and Type Definitions 1.6.1.1 Type ac_callback_t typedef void(* ac_callback_t )(struct ac_module *const module_inst) Type definition for a AC module callback function. 1.6.2 Structure Definitions 1.6.2.1 Struct ac_chan_config Configuration structure for a Comparator channel, to configure the input and output settings of the comparator. Table 1-1. Members Type Name Description bool enable_hysteresis When true, hysteresis mode is enabled on the comparator inputs. enum ac_chan_filter filter Filtering mode for the comparator output, when the comparator is used in a supported mode. enum ac_chan_interrupt_selection interrupt_selection Interrupt criteria for the comparator channel, to select the condition that will trigger a callback. enum ac_chan_neg_mux negative_input Input multiplexer selection for the comparator's negative input pin. Any internal reference source, such as a bandgap reference voltage or the DAC, must be configured and enabled prior to its use as a comparator input. enum ac_chan_output output_mode Output mode of the comparator, whether it should be available for internal use, or asynchronously/ synchronously linked to a GPIO pin. enum ac_chan_pos_mux positive_input Input multiplexer selection for the comparator's positive input pin. enum ac_chan_sample_mode sample_mode Sampling mode of the comparator channel. uint8_t vcc_scale_factor Scaled VCC voltage division factor for the channel, when a comparator pin is connected to the VCC voltage scalar input. The formular is: Vscale = Vdd * vcc_scale_factor / 64. If the VCC voltage scalar is not selected as a AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 16 Type 1.6.2.2 Name Description comparator channel pin's input, this value will be ignored. Struct ac_config Configuration structure for a Comparator channel, to configure the input and output settings of the comparator. Table 1-2. Members 1.6.2.3 Type Name Description bool run_in_standby[] If true, the comparator pairs will continue to sample during sleep mode when triggered. enum gclk_generator source_generator Source generator for AC GCLK. Struct ac_events Event flags for the Analog Comparator module. This is used to enable and disable events via ac_enable_events() and ac_disable_events(). Table 1-3. Members 1.6.2.4 Type Name Description bool generate_event_on_state[] If true, an event will be generated when a comparator state changes. bool generate_event_on_window[] If true, an event will be generated when a comparator window state changes. bool on_event_sample[] If true, a comparator will be sampled each time an event is received. Struct ac_module AC software instance structure, used to retain software state information of an associated hardware module instance. Note 1.6.2.5 The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. Struct ac_win_config Table 1-4. Members Type Name Description enum ac_win_interrupt_selection interrupt_selection Interrupt criteria for the comparator window channel, to select the condition that will trigger a callback. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 17 1.6.3 Macro Definitions 1.6.3.1 Driver Feature Definition Define AC driver feature set according to different device family. Macro FEATURE_AC_RUN_IN_STANDY_PAIR_COMPARATOR #define FEATURE_AC_RUN_IN_STANDY_PAIR_COMPARATOR Run in standby feature for comparator pair 1.6.3.2 AC Window Channel Status Flags AC window channel status flags, returned by ac_win_get_status(). Macro AC_WIN_STATUS_UNKNOWN #define AC_WIN_STATUS_UNKNOWN (1UL << 0) Unknown output state; the comparator window channel was not ready. Macro AC_WIN_STATUS_ABOVE #define AC_WIN_STATUS_ABOVE (1UL << 1) Window Comparator's input voltage is above the window. Macro AC_WIN_STATUS_INSIDE #define AC_WIN_STATUS_INSIDE (1UL << 2) Window Comparator's input voltage is inside the window. Macro AC_WIN_STATUS_BELOW #define AC_WIN_STATUS_BELOW (1UL << 3) Window Comparator's input voltage is below the window. Macro AC_WIN_STATUS_INTERRUPT_SET #define AC_WIN_STATUS_INTERRUPT_SET (1UL << 4) This state reflects the window interrupt flag. When the interrupt flag should be set is configured in ac_win_set_config(). This state needs to be cleared by the of ac_win_clear_status(). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 18 1.6.3.3 AC Channel Status Flags AC channel status flags, returned by ac_chan_get_status(). Macro AC_CHAN_STATUS_UNKNOWN #define AC_CHAN_STATUS_UNKNOWN (1UL << 0) Unknown output state; the comparator channel was not ready. Macro AC_CHAN_STATUS_NEG_ABOVE_POS #define AC_CHAN_STATUS_NEG_ABOVE_POS (1UL << 1) Comparator's negative input pin is higher in voltage than the positive input pin. Macro AC_CHAN_STATUS_POS_ABOVE_NEG #define AC_CHAN_STATUS_POS_ABOVE_NEG (1UL << 2) Comparator's positive input pin is higher in voltage than the negative input pin. Macro AC_CHAN_STATUS_INTERRUPT_SET #define AC_CHAN_STATUS_INTERRUPT_SET (1UL << 3) This state reflects the channel interrupt flag. When the interrupt flag should be set is configured in ac_chan_set_config(). This state needs to be cleared by the of ac_chan_clear_status(). 1.6.4 Function Definitions 1.6.4.1 Configuration and Initialization Function ac_reset() Resets and disables the Analog Comparator driver. enum status_code ac_reset( struct ac_module *const module_inst) Resets and disables the Analog Comparator driver, resets the internal states and registers of the hardware module to their power-on defaults. Table 1-5. Parameters Data direction Parameter name Description [out] module_inst Pointer to the AC software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 19 Function ac_init() Initializes and configures the Analog Comparator driver. enum status_code ac_init( struct ac_module *const module_inst, Ac *const hw, struct ac_config *const config) Initializes the Analog Comparator driver, configuring it to the user supplied configuration parameters, ready for use. This function should be called before enabling the Analog Comparator. Note Once called the Analog Comparator will not be running; to start the Analog Comparator call ac_enable() after configuring the module. Table 1-6. Parameters Data direction Parameter name Description [out] module_inst Pointer to the AC software instance struct [in] hw Pointer to the AC module instance [in] config Pointer to the config struct, created by the user application Function ac_is_syncing() Determines if the hardware module(s) are currently synchronizing to the bus. bool ac_is_syncing( struct ac_module *const module_inst) Checks to see if the underlying hardware peripheral module(s) are currently synchronizing across multiple clock domains to the hardware bus. This function can be used to delay further operations on a module until such time that it is ready, to prevent blocking delays for synchronization in the user application. Table 1-7. Parameters Data direction Parameter name Description [in] module_inst Pointer to the AC software instance struct Returns Synchronization status of the underlying hardware module(s). Table 1-8. Return Values Return value Description false If the module has completed synchronization ture If the module synchronization is ongoing Function ac_get_config_defaults() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 20 Initializes all members of an Analog Comparator configuration structure to safe defaults. void ac_get_config_defaults( struct ac_config *const config) Initializes all members of a given Analog Comparator configuration structure to safe known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● All comparator pairs disabled during sleep mode (if has this feature) ● Generator 0 is the default GCLK generator Table 1-9. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function ac_enable() Enables an Analog Comparator that was previously configured. void ac_enable( struct ac_module *const module_inst) Enables an Analog Comparator that was previously configured via a call to ac_init(). Table 1-10. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral Function ac_disable() Disables an Analog Comparator that was previously enabled. void ac_disable( struct ac_module *const module_inst) Disables an Analog Comparator that was previously started via a call to ac_enable(). Table 1-11. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral Function ac_enable_events() Enables an Analog Comparator event input or output. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 21 void ac_enable_events( struct ac_module *const module_inst, struct ac_events *const events) Enables one or more input or output events to or from the Analog Comparator module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 1-12. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] events Struct containing flags of events to enable Function ac_disable_events() Disables an Analog Comparator event input or output. void ac_disable_events( struct ac_module *const module_inst, struct ac_events *const events) Disables one or more input or output events to or from the Analog Comparator module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 1-13. Parameters 1.6.4.2 Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] events Struct containing flags of events to disable Channel Configuration and Initialization Function ac_chan_get_config_defaults() Initializes all members of an Analog Comparator channel configuration structure to safe defaults. void ac_chan_get_config_defaults( struct ac_chan_config *const config) Initializes all members of an Analog Comparator channel configuration structure to safe defaults. This function should be called on all new instances of these configuration structures before being modified by the user application. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 22 The default configuration is as follows: ● Continuous sampling mode ● Majority of five sample output filter ● Comparator disabled during sleep mode (if has this feature) ● Hysteresis enabled on the input pins ● Hysteresis level of 50mV if having this feature. ● Internal comparator output mode ● Comparator pin multiplexer 0 selected as the positive input ● Scaled VCC voltage selected as the negative input ● VCC voltage scaler set for a division factor of two ● Channel interrupt set to occur when the compare threshold is passed Table 1-14. Parameters Data direction Parameter name Description [out] config Channel configuration structure to initialize to default values Function ac_chan_set_config() Writes an Analog Comparator channel configuration to the hardware module. enum status_code ac_chan_set_config( struct ac_module *const module_inst, const enum ac_chan_channel channel, struct ac_chan_config *const config) Writes a given Analog Comparator channel configuration to the hardware module. Table 1-15. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Analog Comparator channel to configure [in] config Pointer to the channel configuration struct Function ac_chan_enable() Enables an Analog Comparator channel that was previously configured. void ac_chan_enable( struct ac_module *const module_inst, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 23 const enum ac_chan_channel channel) Enables an Analog Comparator channel that was previously configured via a call to ac_chan_set_config(). Table 1-16. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Comparator channel to enable Function ac_chan_disable() Disables an Analog Comparator channel that was previously enabled. void ac_chan_disable( struct ac_module *const module_inst, const enum ac_chan_channel channel) Stops an Analog Comparator channel that was previously started via a call to ac_chan_enable(). Table 1-17. Parameters 1.6.4.3 Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Comparator channel to disable Channel Control Function ac_chan_trigger_single_shot() Triggers a comparison on a comparator that is configured in single shot mode. void ac_chan_trigger_single_shot( struct ac_module *const module_inst, const enum ac_chan_channel channel) Triggers a single conversion on a comparator configured to compare on demand (single shot mode) rather than continuously. Table 1-18. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Comparator channel to trigger Function ac_chan_is_ready() Determines if a given comparator channel is ready for comparisons. bool ac_chan_is_ready( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 24 struct ac_module *const module_inst, const enum ac_chan_channel channel) Checks a comparator channel to see if the comparator is currently ready to begin comparisons. Table 1-19. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Comparator channel to test Returns Comparator channel readiness state. Function ac_chan_get_status() Determines the output state of a comparator channel. uint8_t ac_chan_get_status( struct ac_module *const module_inst, const enum ac_chan_channel channel) Retrieves the last comparison value (after filtering) of a given comparator. If the comparator was not ready at the time of the check, the comparison result will be indicated as being unknown. Table 1-20. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] channel Comparator channel to test Returns Bit mask of comparator channel status flags. Function ac_chan_clear_status() Clears an interrupt status flag. void ac_chan_clear_status( struct ac_module *const module_inst, const enum ac_chan_channel channel) This function is used to clear the AC_CHAN_STATUS_INTERRUPT_SET flag it will clear the flag for the channel indicated by the channel argument. Table 1-21. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 25 1.6.4.4 Data direction Parameter name Description [in] channel Comparator channel to clear Window Mode Configuration and Initialization Function ac_win_get_config_defaults() Initializes an Analog Comparator window configuration structure to defaults. void ac_win_get_config_defaults( struct ac_win_config *const config) Initializes a given Analog Comparator channel configuration structure to a set of known default values. This function should be called if window interrupts are needed and before ac_win_set_config(). The default configuration is as follows: ● Channel interrupt set to occur when the measurement is above the window Table 1-22. Parameters Data direction Parameter name Description [out] config Window configuration structure to initialize to default values Function ac_win_set_config() Function used to setup interrupt selection of a window. enum status_code ac_win_set_config( struct ac_module *const module_inst, enum ac_win_channel const win_channel, struct ac_win_config *const config) This function is used to setup when an interrupt should occur for a given window. Note This must be done before enabling the channel. Table 1-23. Parameters Data direction Parameter name Description [in] module_inst Pointer to software instance struct [in] win_channel Window channel to setup [in] config Configuration for the given window channel Table 1-24. Return Values Return value Description STATUS_OK Function exited successful STATUS_ERR_INVALID_ARG win_channel argument incorrect AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 26 Function ac_win_enable() Enables an Analog Comparator window channel that was previously configured. enum status_code ac_win_enable( struct ac_module *const module_inst, const enum ac_win_channel win_channel) Enables and starts an Analog Comparator window channel. Note The comparator channels used by the window channel must be configured and enabled before calling this function. The two comparator channels forming each window comparator pair must have identical configurations other than the negative pin multiplexer setting. Table 1-25. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] win_channel Comparator window channel to enable Returns Status of the window enable procedure. Table 1-26. Return Values Return value Description STATUS_OK The window comparator was enabled STATUS_ERR_IO One or both comparators in the window comparator pair is disabled STATUS_ERR_BAD_FORMAT The comparator channels in the window pair were not configured correctly Function ac_win_disable() Disables an Analog Comparator window channel that was previously enabled. void ac_win_disable( struct ac_module *const module_inst, const enum ac_win_channel win_channel) Stops an Analog Comparator window channel that was previously started via a call to ac_win_enable(). Table 1-27. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] win_channel Comparator window channel to disable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 27 1.6.4.5 Window Mode Control Function ac_win_is_ready() Determines if a given Window Comparator is ready for comparisons. bool ac_win_is_ready( struct ac_module *const module_inst, const enum ac_win_channel win_channel) Checks a Window Comparator to see if the both comparators used for window detection is currently ready to begin comparisons. Table 1-28. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] win_channel Window Comparator channel to test Returns Window Comparator channel readiness state. Function ac_win_get_status() Determines the state of a specified Window Comparator. uint8_t ac_win_get_status( struct ac_module *const module_inst, const enum ac_win_channel win_channel) Retrieves the current window detection state, indicating what the input signal is currently comparing to relative to the window boundaries. Table 1-29. Parameters Returns Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] win_channel Comparator Window channel to test Bit mask of Analog Comparator window channel status flags. Function ac_win_clear_status() Clears an interrupt status flag. void ac_win_clear_status( struct ac_module *const module_inst, const enum ac_win_channel win_channel) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 28 This function is used to clear the AC_WIN_STATUS_INTERRUPT_SET flag it will clear the flag for the channel indicated by the win_channel argument. Table 1-30. Parameters Data direction Parameter name Description [in] module_inst Software instance for the Analog Comparator peripheral [in] win_channel Window channel to clear 1.6.5 Enumeration Definitions 1.6.5.1 Enum ac_callback Enum for possible callback types for the AC module. Table 1-31. Members 1.6.5.2 Enum value Description AC_CALLBACK_COMPARATOR_0 Callback for comparator 0. AC_CALLBACK_COMPARATOR_1 Callback for comparator 1. AC_CALLBACK_WINDOW_0 Callback for window 0. Enum ac_chan_channel Enum for the possible comparator channels. Table 1-32. Members 1.6.5.3 Enum value Description AC_CHAN_CHANNEL_0 Comparator channel 0 (Pair 0, Comparator 0). AC_CHAN_CHANNEL_1 Comparator channel 1 (Pair 0, Comparator 1). AC_CHAN_CHANNEL_2 Comparator channel 2 (Pair 1, Comparator 0). AC_CHAN_CHANNEL_3 Comparator channel 3 (Pair 1, Comparator 1). Enum ac_chan_filter Enum for the possible channel output filtering configurations of an Analog Comparator channel. Table 1-33. Members 1.6.5.4 Enum value Description AC_CHAN_FILTER_NONE No output filtering is performed on the comparator channel. AC_CHAN_FILTER_MAJORITY_3 Comparator channel output is passed through a Majority-of-Three filter. AC_CHAN_FILTER_MAJORITY_5 Comparator channel output is passed through a Majority-of-Five filter. Enum ac_chan_interrupt_selection This enum is used to select when a channel interrupt should occur. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 29 Table 1-34. Members Enum value Description AC_CHAN_INTERRUPT_SELECTION_TOGGLE An interrupt will be generated when the comparator level is passed. AC_CHAN_INTERRUPT_SELECTION_RISING An interrupt will be generated when the measurement goes above the compare level. AC_CHAN_INTERRUPT_SELECTION_FALLING An interrupt will be generated when the measurement goes below the compare level. AC_CHAN_INTERRUPT_SELECTION_END_OF_COMPARE An interrupt will be generated when a new measurement is complete. Interrupts will only be generated in single shot mode. This state needs to be cleared by the use of ac_chan_cleare_status(). 1.6.5.5 Enum ac_chan_neg_mux Enum for the possible channel negative pin input of an Analog Comparator channel. Table 1-35. Members 1.6.5.6 Enum value Description AC_CHAN_NEG_MUX_PIN0 Negative comparator input is connected to physical AC input pin 0. AC_CHAN_NEG_MUX_PIN1 Negative comparator input is connected to physical AC input pin 1. AC_CHAN_NEG_MUX_PIN2 Negative comparator input is connected to physical AC input pin 2. AC_CHAN_NEG_MUX_PIN3 Negative comparator input is connected to physical AC input pin 3. AC_CHAN_NEG_MUX_GND Negative comparator input is connected to the internal ground plane. AC_CHAN_NEG_MUX_SCALED_VCC Negative comparator input is connected to the channel's internal VCC plane voltage scalar. AC_CHAN_NEG_MUX_BANDGAP Negative comparator input is connected to the internal band gap voltage reference. AC_CHAN_NEG_MUX_DAC0 For SAMD20/D21/D10/D11/R21: Negative comparator input is connected to the channel's internal DAC channel 0 output. For SAML21: Negative comparator input is connected to the channel's internal DAC channel 0 output for Comparator 0 or OPAMP output for Comparator 1. Enum ac_chan_output Enum for the possible channel GPIO output routing configurations of an Analog Comparator channel. Table 1-36. Members Enum value Description AC_CHAN_OUTPUT_INTERNAL Comparator channel output is not routed to a physical GPIO pin, and is used internally only. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 30 1.6.5.7 Enum value Description AC_CHAN_OUTPUT_ASYNCRONOUS Comparator channel output is routed to its matching physical GPIO pin, via an asynchronous path. AC_CHAN_OUTPUT_SYNCHRONOUS Comparator channel output is routed to its matching physical GPIO pin, via a synchronous path. Enum ac_chan_pos_mux Enum for the possible channel positive pin input of an Analog Comparator channel. Table 1-37. Members 1.6.5.8 Enum value Description AC_CHAN_POS_MUX_PIN0 Positive comparator input is connected to physical AC input pin 0. AC_CHAN_POS_MUX_PIN1 Positive comparator input is connected to physical AC input pin 1. AC_CHAN_POS_MUX_PIN2 Positive comparator input is connected to physical AC input pin 2. AC_CHAN_POS_MUX_PIN3 Positive comparator input is connected to physical AC input pin 3. Enum ac_chan_sample_mode Enum for the possible channel sampling modes of an Analog Comparator channel. Table 1-38. Members 1.6.5.9 Enum value Description AC_CHAN_MODE_CONTINUOUS Continuous sampling mode; when the channel is enabled the comparator output is available for reading at any time. AC_CHAN_MODE_SINGLE_SHOT Single shot mode; when used the comparator channel must be triggered to perform a comparison before reading the result. Enum ac_win_channel Enum for the possible window comparator channels. Table 1-39. Members Enum value Description AC_WIN_CHANNEL_0 Window channel 0 (Pair 0, Comparators 0 and 1). AC_WIN_CHANNEL_1 Window channel 1 (Pair 1, Comparators 2 and 3). 1.6.5.10 Enum ac_win_interrupt_selection AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 31 This enum is used to select when a window interrupt should occur. Table 1-40. Members Enum value Description AC_WIN_INTERRUPT_SELECTION_ABOVE Interrupt is generated when the compare value goes above the window. AC_WIN_INTERRUPT_SELECTION_INSIDE Interrupt is generated when the compare value goes inside the window. AC_WIN_INTERRUPT_SELECTION_BELOW Interrupt is generated when the compare value goes below the window. AC_WIN_INTERRUPT_SELECTION_OUTSIDE Interrupt is generated when the compare value goes outside the window. 1.7 Extra Information for AC Driver 1.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 1.7.2 Acronym Description AC Analog Comparator DAC Digital-to-Analog Converter MUX Multiplexer Dependencies This driver has the following dependencies: ● 1.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 1.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAMD21 Initial Release 1.8 Examples for AC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Analog Comparator Driver (AC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_ac_basic_use_case ● asfdoc_sam0_ac_callback_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 32 2. SAM Analog to Digital Converter Driver (ADC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Analog to Digital Converter functionality, for the conversion of analog voltages into a corresponding digital form. The following driver API modes are covered by this manual: ● Polled APIs The following peripherals are used by this module: ● ADC (Analog to Digital Converter) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 The outline of this documentation is as follows: 2.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 2.2 Module Overview This driver provides an interface for the Analog-to-Digital conversion functions on the device, to convert analog voltages to a corresponding digital value. The ADC has up to 12-bit resolution, and is capable of converting up to 500K samples per second (Ksps). The ADC has a compare function for accurate monitoring of user defined thresholds with minimum software intervention required. The ADC may be configured for 8-, 10-, or 12-bit result, reducing the conversion time. ADC conversion results are provided left or right adjusted which eases calculation when the result is represented as a signed integer. The input selection is flexible, and both single-ended and differential measurements can be made. For differential measurements, an optional gain stage is available to increase the dynamic range. In addition, several internal signal inputs are available. The ADC can provide both signed and unsigned results. The ADC measurements can either be started by application software or an incoming event from another peripheral in the device, and both internal and external reference voltages can be selected. Note Internal references will be enabled by the driver, but not disabled. Any reference not used by the application should be disabled by the application. A simplified block diagram of the ADC can be seen in Figure 2-1: Module Overview on page 34. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 33 Figure 2-1. Module Overview P RE S CALE R P o s it ive in p u t N e g a t ive in p u t ADC P o s t p r o c e s s in g RE S U LT Re fe r e n c e 2.2.1 Sample Clock Prescaler The ADC features a prescaler, which enables conversion at lower clock rates than the input Generic Clock to the ADC module. This feature can be used to lower the synchronization time of the digital interface to the ADC module via a high speed Generic Clock frequency, while still allowing the ADC sampling rate to be reduced. 2.2.2 ADC Resolution The ADC supports full 8-bit, 10-bit, or 12-bit resolution. Hardware oversampling and decimation can be used to increase the effective resolution at the expense of throughput. Using oversampling and decimation mode the ADC resolution is increased from 12-bit to an effective 13-, 14-, 15-, or 16-bit. In these modes the conversion rate is reduced, as a greater number of samples is used to achieve the increased resolution. The available resolutions and effective conversion rate is listed in Table 2-1: Effective ADC Conversion Speed Using Oversampling on page 34. Table 2-1. Effective ADC Conversion Speed Using Oversampling 2.2.3 Resolution Effective conversion rate 13-bit Conversion rate divided by 4 14-bit Conversion rate divided by 16 15-bit Conversion rate divided by 64 16-bit Conversion rate divided by 256 Conversion Modes ADC conversions can be software triggered on demand by the user application, if continuous sampling is not required. It is also possible to configure the ADC in free-running mode, where new conversions are started as soon as the previous conversion is completed, or configure the ADC to scan across a number of input pins (see Pin Scan). 2.2.4 Differential and Single-Ended Conversion The ADC has two conversion modes; differential and single-ended. When measuring signals where the positive input pin is always at a higher voltage than the negative input pin, the single-ended conversion mode should be used in order to achieve a full 12-bit output resolution. If however the positive input pin voltage may drop below the negative input pin the signed differential mode should be used. 2.2.5 Sample Time The sample time for each ADC conversion is configurable as a number of half prescaled ADC clock cycles (depending on the prescaler value), allowing the user application to achieve faster or slower sampling depending AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 34 on the source impedance of the ADC input channels. For applications with high impedance inputs the sample time can be increased to give the ADC an adequate time to sample and convert the input channel. The resulting sampling time is given by the following equation: (2.1) 2.2.6 Averaging The ADC can be configured to trade conversion speed for accuracy by averaging multiple samples in hardware. This feature is suitable when operating in noisy conditions. You can specify any number of samples to accumulate (up to 1024) and the divide ratio to use (up to divide by 128). To modify these settings the ADC_RESOLUTION_CUSTOM needs to be set as the resolution. When this is set the number of samples to accumulate and the division ratio can be set by the configuration struct members adc_config::accumulate_samples and adc_config::divide_result. When using this mode the ADC result register will be set to be 16-bit wide to accommodate the larger result sizes produced by the accumulator. The effective ADC conversion rate will be reduced by a factor of the number of accumulated samples; however the effective resolution will be increased according to Table 2-2: Effective ADC Resolution From Various Hardware Averaging Modes on page 35. Table 2-2. Effective ADC Resolution From Various Hardware Averaging Modes 2.2.7 Number of samples Final result 1 12-bit 2 13-bit 4 14-bit 8 15-bit 16 16-bit 32 16-bit 64 16-bit 128 16-bit 256 16-bit 512 16-bit 1024 16-bit Offset and Gain Correction Inherent gain and offset errors affect the absolute accuracy of the ADC. The offset error is defined as the deviation of the ADC## actual transfer function from ideal straight line at zero input voltage. The gain error is defined as the deviation of the last output step's midpoint from the ideal straight line, after compensating for offset error. The offset correction value is subtracted from the converted data before the result is ready. The gain correction value is multiplied with the offset corrected value. The equation for both offset and gain error compensation is shown below: (2.2) When enabled, a given set of offset and gain correction values can be applied to the sampled data in hardware, giving a corrected stream of sample data to the user application at the cost of an increased sample latency. In single conversion, a latency of 13 ADC Generic Clock cycles is added for the final sample result availability. As the correction time is always less than the propagation delay, in free running mode this latency appears only during the first conversion. After the first conversion is complete future conversion results are available at the defined sampling rate. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 35 2.2.8 Pin Scan In pin scan mode, the first ADC conversion will begin from the configured positive channel, plus the requested starting offset. When the first conversion is completed, the next conversion will start at the next positive input channel and so on, until all requested pins to scan have been sampled and converted. SAM L21 has automatic sequences feature instead of pin scan mode. In automatic sequence mode, all of 32 positives inputs can be included in a sequence. The sequence starts from the lowest input, and go to the next enabled input automatically. Pin scanning gives a simple mechanism to sample a large number of physical input channel samples, using a single physical ADC channel. 2.2.9 Window Monitor The ADC module window monitor function can be used to automatically compare the conversion result against a preconfigured pair of upper and lower threshold values. The threshold values are evaluated differently, depending on whether differential or single-ended mode is selected. In differential mode, the upper and lower thresholds are evaluated as signed values for the comparison, while in single-ended mode the comparisons are made as a set of unsigned values. The significant bits of the lower window monitor threshold and upper window monitor threshold values are userconfigurable, and follow the overall ADC sampling bit precision set when the ADC is configured by the user application. For example, only the eight lower bits of the window threshold values will be compares to the sampled th data whilst the ADC is configured in 8-bit mode. In addition, if using differential mode, the 8 bit will be considered as the sign bit even if bit 9 is zero. 2.2.10 Events Event generation and event actions are configurable in the ADC. The ADC has two actions that can be triggered upon event reception: ● Start conversion ● Flush pipeline and start conversion The ADC can generate two events: ● Window monitor ● Result ready If the event actions are enabled in the configuration, any incoming event will trigger the action. If the window monitor event is enabled, an event will be generated when the configured window condition is detected. If the result ready event is enabled, an event will be generated when a conversion is completed. Note 2.3 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Special Considerations An integrated analog temperature sensor is available for use with the ADC. The bandgap voltage, as well as the scaled I/O and core voltages can also be measured by the ADC. For internal ADC inputs, the internal source(s) may need to be manually enabled by the user application before they can be measured. 2.4 Extra Information For extra information, see Extra Information for ADC Driver. This includes: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 36 2.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for ADC Driver. 2.6 API Overview 2.6.1 Structure Definitions 2.6.1.1 Struct adc_config Configuration structure for an ADC instance. This structure should be initialized by the adc_get_config_defaults() function before being modified by the user application. Table 2-3. Members Type Name Description enum adc_accumulate_samples accumulate_samples Number of ADC samples to accumulate when using the ADC_RESOLUTION_CUSTOM mode. enum adc_clock_prescaler clock_prescaler Clock prescaler. enum gclk_generator clock_source GCLK generator used to clock the peripheral. struct adc_correction_config correction Gain and offset correction configuration structure. bool differential_mode Enables differential mode if true. enum adc_divide_result divide_result Division ration when using the ADC_RESOLUTION_CUSTOM mode. enum adc_event_action event_action Event action to take on incoming event. bool freerunning Enables free running mode if true. enum adc_gain_factor gain_factor Gain factor. bool left_adjust Left adjusted result. enum adc_negative_input negative_input Negative MUX input. struct adc_pin_scan_config pin_scan Pin scan configuration structure. enum adc_positive_input positive_input Positive MUX input. enum adc_reference reference Voltage reference. bool reference_compensation_enable Enables reference buffer offset compensation if true. This will increase the accuracy of the gain stage, but decreases the input impedance; therefore the startup time of the reference must be increased. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 37 2.6.1.2 Type Name Description enum adc_resolution resolution Result resolution. bool run_in_standby Enables ADC in standby sleep mode if true. uint8_t sample_length This value (0-63) control the ADC sampling time in number of half ADC prescaled clock cycles (depends of ADC_PRESCALER value), thus controlling the ADC input impedance. Sampling time is set according to the formula: Sample time = (sample_length+1) * (ADCclk / 2) struct adc_window_config window Window monitor configuration structure. Struct adc_correction_config Gain and offset correction configuration structure. Part of the adc_config struct and will be initialized by adc_get_config_defaults. Table 2-4. Members 2.6.1.3 Type Name Description bool correction_enable Enables correction for gain and offset based on values of gain_correction and offset_correction if set to true. uint16_t gain_correction This value defines how the ADC conversion result is compensated for gain error before written to the result register. This is a fractional value, 1-bit integer plus an 11-bit fraction, therefore 1/2 <= gain_correction < 2. Valid gain_correction values ranges from 0b010000000000 to 0b111111111111. int16_t offset_correction This value defines how the ADC conversion result is compensated for offset error before written to the result register. This is a 12-bit value in two## complement format. Struct adc_events Event flags for the ADC module. This is used to enable and disable events via adc_enable_events() and adc_disable_events(). Table 2-5. Members Type Name Description bool generate_event_on_conversion_done Enable event generation on conversion done. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 38 2.6.1.4 Type Name Description bool generate_event_on_window_monitor Enable event generation on window monitor. Struct adc_module ADC software instance structure, used to retain software state information of an associated hardware module instance. Note 2.6.1.5 The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. Struct adc_pin_scan_config Pin scan configuration structure. Part of the adc_config struct and will be initialized by adc_get_config_defaults. Table 2-6. Members 2.6.1.6 Type Name Description uint8_t inputs_to_scan Number of input pins to scan in pin scan mode. A value below two will disable pin scan mode. uint8_t offset_start_scan Offset (relative to selected positive input) of the first input pin to be used in pin scan mode. Type Name Description int32_t window_lower_value Lower window value. enum adc_window_mode window_mode Selected window mode. int32_t window_upper_value Upper window value. Struct adc_window_config Window monitor configuration structure. Table 2-7. Members 2.6.2 Macro Definitions 2.6.2.1 Module Status Flags ADC status flags, returned by adc_get_status() and cleared by adc_clear_status(). Macro ADC_STATUS_RESULT_READY #define ADC_STATUS_RESULT_READY (1UL << 0) ADC result ready. Macro ADC_STATUS_WINDOW AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 39 #define ADC_STATUS_WINDOW (1UL << 1) Window monitor match. Macro ADC_STATUS_OVERRUN #define ADC_STATUS_OVERRUN (1UL << 2) ADC result overwritten before read. 2.6.3 Function Definitions 2.6.3.1 Driver Initialization and Configuration Function adc_init() Initializes the ADC. enum status_code adc_init( struct adc_module *const module_inst, Adc * hw, struct adc_config * config) Initializes the ADC device struct and the hardware module based on the given configuration struct values. Table 2-8. Parameters Returns Data direction Parameter name Description [out] module_inst Pointer to the ADC software instance struct [in] hw Pointer to the ADC module instance [in] config Pointer to the configuration struct Status of the initialization procedure. Table 2-9. Return Values Return value Description STATUS_OK The initialization was successful STATUS_ERR_INVALID_ARG Invalid argument(s) were provided STATUS_BUSY The module is busy with a reset operation STATUS_ERR_DENIED The module is enabled Function adc_get_config_defaults() Initializes an ADC configuration structure to defaults. void adc_get_config_defaults( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 40 struct adc_config *const config) 2 Support and FAQ: visit Atmel Support Initializes a given ADC configuration struct to a set of known default values. This function should be called on any new instance of the configuration struct before being modified by the user application. The default configuration is as follows: ● GCLK generator 0 (GCLK main) clock source ● 1V from internal bandgap reference ● Div 4 clock prescaler ● 12 bit resolution ● Window monitor disabled ● No gain ● Positive input on ADC PIN 0 ● Negative input on ADC PIN 1 ● Averaging disabled ● Oversampling disabled ● Right adjust data ● Single-ended mode ● Free running disabled ● All events (input and generation) disabled ● Sleep operation disabled ● No reference compensation ● No gain/offset correction ● No added sampling time ● Pin scan mode disabled Table 2-10. Parameters 2.6.3.2 Data direction Parameter name Description [out] config Pointer to configuration struct to initialize to default values Status Management Function adc_get_status() Retrieves the current module status. uint32_t adc_get_status( struct adc_module *const module_inst) 2 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 41 Retrieves the status of the module, giving overall state information. Table 2-11. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct Returns Bitmask of ADC_STATUS_* flags. Table 2-12. Return Values Return value Description ADC_STATUS_RESULT_READY ADC Result is ready to be read ADC_STATUS_WINDOW ADC has detected a value inside the set window range ADC_STATUS_OVERRUN ADC result has overrun Function adc_clear_status() Clears a module status flag. void adc_clear_status( struct adc_module *const module_inst, const uint32_t status_flags) Clears the given status flag of the module. Table 2-13. Parameters 2.6.3.3 Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] status_flags Bitmask of ADC_STATUS_* flags to clear Enable, Disable and Reset ADC Module, Start Conversion and Read Result Function adc_enable() Enables the ADC module. enum status_code adc_enable( struct adc_module *const module_inst) Enables an ADC module that has previously been configured. If any internal reference is selected it will be enabled. Table 2-14. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 42 Function adc_disable() Disables the ADC module. enum status_code adc_disable( struct adc_module *const module_inst) Disables an ADC module that was previously enabled. Table 2-15. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct Function adc_reset() Resets the ADC module. enum status_code adc_reset( struct adc_module *const module_inst) Resets an ADC module, clearing all module state and registers to their default values. Table 2-16. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct Function adc_enable_events() Enables an ADC event input or output. void adc_enable_events( struct adc_module *const module_inst, struct adc_events *const events) Enables one or more input or output events to or from the ADC module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 2-17. Parameters Data direction Parameter name Description [in] module_inst Software instance for the ADC peripheral [in] events Struct containing flags of events to enable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 43 Function adc_disable_events() Disables an ADC event input or output. void adc_disable_events( struct adc_module *const module_inst, struct adc_events *const events) Disables one or more input or output events to or from the ADC module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 2-18. Parameters Data direction Parameter name Description [in] module_inst Software instance for the ADC peripheral [in] events Struct containing flags of events to disable Function adc_start_conversion() Starts an ADC conversion. void adc_start_conversion( struct adc_module *const module_inst) Starts a new ADC conversion. Table 2-19. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct Function adc_read() Reads the ADC result. enum status_code adc_read( struct adc_module *const module_inst, uint16_t * result) Reads the result from an ADC conversion that was previously started. Table 2-20. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [out] result Pointer to store the result value in AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 44 Returns Status of the ADC read request. Table 2-21. Return Values 2.6.3.4 Return value Description STATUS_OK The result was retrieved successfully STATUS_BUSY A conversion result was not ready STATUS_ERR_OVERFLOW The result register has been overwritten by the ADC module before the result was read by the software Runtime Changes of ADC Module Function adc_flush() Flushes the ADC pipeline. void adc_flush( struct adc_module *const module_inst) Flushes the pipeline and restart the ADC clock on the next peripheral clock edge. All conversions in progress will be lost. When flush is complete, the module will resume where it left off. Table 2-22. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct Function adc_set_window_mode() Sets the ADC window mode. void adc_set_window_mode( struct adc_module *const module_inst, const enum adc_window_mode window_mode, const int16_t window_lower_value, const int16_t window_upper_value) Sets the ADC window mode to a given mode and value range. Table 2-23. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] window_mode Window monitor mode to set [in] window_lower_value Lower window monitor threshold value [in] window_upper_value Upper window monitor threshold value AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 45 Function adc_set_positive_input() Sets positive ADC input pin. void adc_set_positive_input( struct adc_module *const module_inst, const enum adc_positive_input positive_input) Sets the positive ADC input pin selection. Table 2-24. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] positive_input Positive input pin Function adc_set_negative_input() Sets negative ADC input pin for differential mode. void adc_set_negative_input( struct adc_module *const module_inst, const enum adc_negative_input negative_input) Sets the negative ADC input pin, when the ADC is configured in differential mode. Table 2-25. Parameters 2.6.3.5 Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] negative_input Negative input pin Enable and Disable Interrupts Function adc_enable_interrupt() Enable interrupt. void adc_enable_interrupt( struct adc_module *const module_inst, enum adc_interrupt_flag interrupt) Enable the given interrupt request from the ADC module. Table 2-26. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] interrupt Interrupt to enable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 46 Function adc_disable_interrupt() Disable interrupt. void adc_disable_interrupt( struct adc_module *const module_inst, enum adc_interrupt_flag interrupt) Disable the given interrupt request from the ADC module. Table 2-27. Parameters 2.6.3.6 Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] interrupt Interrupt to disable Callback Management Function adc_register_callback() Registers a callback. void adc_register_callback( struct adc_module *const module, adc_callback_t callback_func, enum adc_callback callback_type) Registers a callback function which is implemented by the user. Note The callback must be enabled by for the interrupt handler to call it when the condition for the callback is met. Table 2-28. Parameters Data direction Parameter name Description [in] module Pointer to ADC software instance struct [in] callback_func Pointer to callback function [in] callback_type Callback type given by an enum Function adc_unregister_callback() Unregisters a callback. void adc_unregister_callback( struct adc_module * module, enum adc_callback callback_type) Unregisters a callback function which is implemented by the user. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 47 Table 2-29. Parameters Data direction Parameter name Description [in] module Pointer to ADC software instance struct [in] callback_type Callback type given by an enum Function adc_enable_callback() Enables callback. void adc_enable_callback( struct adc_module *const module, enum adc_callback callback_type) Enables the callback function registered by adc_register_callback. The callback function will be called from the interrupt handler when the conditions for the callback type are met. Table 2-30. Parameters Data direction Parameter name Description [in] module Pointer to ADC software instance struct [in] callback_type Callback type given by an enum Returns Status of the operation. Table 2-31. Return Values Return value Description STATUS_OK If operation was completed STATUS_ERR_INVALID If operation was not completed, due to invalid callback_type Function adc_disable_callback() Disables callback. void adc_disable_callback( struct adc_module *const module, enum adc_callback callback_type) Disables the callback function registered by the adc_register_callback. Table 2-32. Parameters Data direction Parameter name Description [in] module Pointer to ADC software instance struct [in] callback_type Callback type given by an enum AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 48 Returns Status of the operation. Table 2-33. Return Values 2.6.3.7 Return value Description STATUS_OK If operation was completed STATUS_ERR_INVALID If operation was not completed, due to invalid callback_type Job Management Function adc_read_buffer_job() Read multiple samples from ADC. enum status_code adc_read_buffer_job( struct adc_module *const module_inst, uint16_t * buffer, uint16_t samples) Read samples samples from the ADC into the buffer buffer. If there is no hardware trigger defined (event action) the driver will retrigger the ADC conversion whenever a conversion is complete until samples samples has been acquired. To avoid jitter in the sampling frequency using an event trigger is advised. Table 2-34. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] samples Number of samples to acquire [out] buffer Buffer to store the ADC samples Status of the job start. Table 2-35. Return Values Return value Description STATUS_OK The conversion job was started successfully and is in progress STATUS_BUSY The ADC is already busy with another job Function adc_get_job_status() Gets the status of a job. enum status_code adc_get_job_status( struct adc_module * module_inst, enum adc_job_type type) Gets the status of an ongoing or the last job. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 49 Table 2-36. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] type Type of job to abort Returns Status of the job. Function adc_abort_job() Aborts an ongoing job. void adc_abort_job( struct adc_module * module_inst, enum adc_job_type type) Aborts an ongoing job. Table 2-37. Parameters 2.6.3.8 Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] type Type of job to abort ADC Gain and Pin Scan Mode Function adc_set_gain() Sets ADC gain factor. void adc_set_gain( struct adc_module *const module_inst, const enum adc_gain_factor gain_factor) Sets the ADC gain factor to a specified gain setting. Table 2-38. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] gain_factor Gain factor value to set Function adc_set_pin_scan_mode() Sets the ADC pin scan mode. enum status_code adc_set_pin_scan_mode( struct adc_module *const module_inst, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 50 uint8_t inputs_to_scan, const uint8_t start_offset) Configures the pin scan mode of the ADC module. In pin scan mode, the first conversion will start at the configured positive input + start_offset. When a conversion is done, a conversion will start on the next input, until inputs_to_scan number of conversions are made. Table 2-39. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct [in] inputs_to_scan Number of input pins to perform a conversion on (must be two or more) [in] start_offset Offset of first pin to scan (relative to configured positive input) Returns Status of the pin scan configuration set request. Table 2-40. Return Values Return value Description STATUS_OK Pin scan mode has been set successfully STATUS_ERR_INVALID_ARG Number of input pins to scan or offset has an invalid value Function adc_disable_pin_scan_mode() Disables pin scan mode. void adc_disable_pin_scan_mode( struct adc_module *const module_inst) Disables pin scan mode. The next conversion will be made on only one pin (the configured positive input pin). Table 2-41. Parameters Data direction Parameter name Description [in] module_inst Pointer to the ADC software instance struct 2.6.4 Enumeration Definitions 2.6.4.1 Enum adc_accumulate_samples Enum for the possible numbers of ADC samples to accumulate. This setting is only used when the ADC_RESOLUTION_CUSTOM on page 55 resolution setting is used. Table 2-42. Members Enum value Description ADC_ACCUMULATE_DISABLE No averaging. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 51 2.6.4.2 Enum value Description ADC_ACCUMULATE_SAMPLES_2 Average 2 samples. ADC_ACCUMULATE_SAMPLES_4 Average 4 samples. ADC_ACCUMULATE_SAMPLES_8 Average 8 samples. ADC_ACCUMULATE_SAMPLES_16 Average 16 samples. ADC_ACCUMULATE_SAMPLES_32 Average 32 samples. ADC_ACCUMULATE_SAMPLES_64 Average 64 samples. ADC_ACCUMULATE_SAMPLES_128 Average 128 samples. ADC_ACCUMULATE_SAMPLES_256 Average 265 samples. ADC_ACCUMULATE_SAMPLES_512 Average 512 samples. ADC_ACCUMULATE_SAMPLES_1024 Average 1024 samples. Enum adc_clock_prescaler Enum for the possible clock prescaler values for the ADC. Table 2-43. Members 2.6.4.3 Enum value Description ADC_CLOCK_PRESCALER_DIV4 ADC clock division factor 4. ADC_CLOCK_PRESCALER_DIV8 ADC clock division factor 8. ADC_CLOCK_PRESCALER_DIV16 ADC clock division factor 16. ADC_CLOCK_PRESCALER_DIV32 ADC clock division factor 32. ADC_CLOCK_PRESCALER_DIV64 ADC clock division factor 64. ADC_CLOCK_PRESCALER_DIV128 ADC clock division factor 128. ADC_CLOCK_PRESCALER_DIV256 ADC clock division factor 256. ADC_CLOCK_PRESCALER_DIV512 ADC clock division factor 512. Enum adc_divide_result Enum for the possible division factors to use when accumulating multiple samples. To keep the same resolution for the averaged result and the actual input value, the division factor must be equal to the number of samples accumulated. This setting is only used when the ADC_RESOLUTION_CUSTOM on page 55 resolution setting is used. Table 2-44. Members Enum value Description ADC_DIVIDE_RESULT_DISABLE Don't divide result register after accumulation. ADC_DIVIDE_RESULT_2 Divide result register by 2 after accumulation. ADC_DIVIDE_RESULT_4 Divide result register by 4 after accumulation. ADC_DIVIDE_RESULT_8 Divide result register by 8 after accumulation. ADC_DIVIDE_RESULT_16 Divide result register by 16 after accumulation. ADC_DIVIDE_RESULT_32 Divide result register by 32 after accumulation. ADC_DIVIDE_RESULT_64 Divide result register by 64 after accumulation. ADC_DIVIDE_RESULT_128 Divide result register by 128 after accumulation. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 52 2.6.4.4 Enum adc_event_action Enum for the possible actions to take on an incoming event. Table 2-45. Members 2.6.4.5 Enum value Description ADC_EVENT_ACTION_DISABLED Event action disabled. ADC_EVENT_ACTION_FLUSH_START_CONV Flush ADC and start conversion. ADC_EVENT_ACTION_START_CONV Start conversion. Enum adc_gain_factor Enum for the possible gain factor values for the ADC. Table 2-46. Members 2.6.4.6 Enum value Description ADC_GAIN_FACTOR_1X 1x gain. ADC_GAIN_FACTOR_2X 2x gain. ADC_GAIN_FACTOR_4X 4x gain. ADC_GAIN_FACTOR_8X 8x gain. ADC_GAIN_FACTOR_16X 16x gain. ADC_GAIN_FACTOR_DIV2 1/2x gain. Enum adc_interrupt_flag Enum for the possible ADC interrupt flags. Table 2-47. Members 2.6.4.7 Enum value Description ADC_INTERRUPT_RESULT_READY ADC result ready. ADC_INTERRUPT_WINDOW Window monitor match. ADC_INTERRUPT_OVERRUN ADC result overwritten before read. Enum adc_job_type Enum for the possible types of ADC asynchronous jobs that may be issued to the driver. Table 2-48. Members 2.6.4.8 Enum value Description ADC_JOB_READ_BUFFER Asynchronous ADC read into a user provided buffer. Enum adc_negative_input Enum for the possible negative MUX input selections for the ADC. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 53 Table 2-49. Members 2.6.4.9 Enum value Description ADC_NEGATIVE_INPUT_PIN0 ADC0 pin. ADC_NEGATIVE_INPUT_PIN1 ADC1 pin. ADC_NEGATIVE_INPUT_PIN2 ADC2 pin. ADC_NEGATIVE_INPUT_PIN3 ADC3 pin. ADC_NEGATIVE_INPUT_PIN4 ADC4 pin. ADC_NEGATIVE_INPUT_PIN5 ADC5 pin. ADC_NEGATIVE_INPUT_PIN6 ADC6 pin. ADC_NEGATIVE_INPUT_PIN7 ADC7 pin. ADC_NEGATIVE_INPUT_GND Internal ground. ADC_NEGATIVE_INPUT_IOGND I/O ground. Enum adc_oversampling_and_decimation Enum for the possible numbers of bits resolution can be increased by when using oversampling and decimation. Table 2-50. Members Enum value Description ADC_OVERSAMPLING_AND_DECIMATION_DISABLE Don't use oversampling and decimation mode. ADC_OVERSAMPLING_AND_DECIMATION_1BIT 1 bit resolution increase. ADC_OVERSAMPLING_AND_DECIMATION_2BIT 2 bits resolution increase. ADC_OVERSAMPLING_AND_DECIMATION_3BIT 3 bits resolution increase. ADC_OVERSAMPLING_AND_DECIMATION_4BIT 4 bits resolution increase. 2.6.4.10 Enum adc_positive_input Enum for the possible positive MUX input selections for the ADC. Table 2-51. Members Enum value Description ADC_POSITIVE_INPUT_PIN0 ADC0 pin. ADC_POSITIVE_INPUT_PIN1 ADC1 pin. ADC_POSITIVE_INPUT_PIN2 ADC2 pin. ADC_POSITIVE_INPUT_PIN3 ADC3 pin. ADC_POSITIVE_INPUT_PIN4 ADC4 pin. ADC_POSITIVE_INPUT_PIN5 ADC5 pin. ADC_POSITIVE_INPUT_PIN6 ADC6 pin. ADC_POSITIVE_INPUT_PIN7 ADC7 pin. ADC_POSITIVE_INPUT_PIN8 ADC8 pin. ADC_POSITIVE_INPUT_PIN9 ADC9 pin. ADC_POSITIVE_INPUT_PIN10 ADC10 pin. ADC_POSITIVE_INPUT_PIN11 ADC11 pin. ADC_POSITIVE_INPUT_PIN12 ADC12 pin. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 54 Enum value Description ADC_POSITIVE_INPUT_PIN13 ADC13 pin. ADC_POSITIVE_INPUT_PIN14 ADC14 pin. ADC_POSITIVE_INPUT_PIN15 ADC15 pin. ADC_POSITIVE_INPUT_PIN16 ADC16 pin. ADC_POSITIVE_INPUT_PIN17 ADC17 pin. ADC_POSITIVE_INPUT_PIN18 ADC18 pin. ADC_POSITIVE_INPUT_PIN19 ADC19 pin. ADC_POSITIVE_INPUT_TEMP Temperature reference. ADC_POSITIVE_INPUT_BANDGAP Bandgap voltage. ADC_POSITIVE_INPUT_SCALEDCOREVCC 1/4 scaled core supply. ADC_POSITIVE_INPUT_SCALEDIOVCC 1/4 scaled I/O supply. ADC_POSITIVE_INPUT_DAC DAC input. 2.6.4.11 Enum adc_reference Enum for the possible reference voltages for the ADC. Table 2-52. Members Enum value Description ADC_REFERENCE_INT1V 1.0V voltage reference. ADC_REFERENCE_INTVCC0 1/1.48VCC reference. ADC_REFERENCE_INTVCC1 1/2VCC (only for internal VCC > 2.1V). ADC_REFERENCE_AREFA External reference A. ADC_REFERENCE_AREFB External reference B. 2.6.4.12 Enum adc_resolution Enum for the possible resolution values for the ADC. Table 2-53. Members Enum value Description ADC_RESOLUTION_12BIT ADC 12-bit resolution. ADC_RESOLUTION_16BIT ADC 16-bit resolution using oversampling and decimation. ADC_RESOLUTION_10BIT ADC 10-bit resolution. ADC_RESOLUTION_8BIT ADC 8-bit resolution. ADC_RESOLUTION_13BIT ADC 13-bit resolution using oversampling and decimation. ADC_RESOLUTION_14BIT ADC 14-bit resolution using oversampling and decimation. ADC_RESOLUTION_15BIT ADC 15-bit resolution using oversampling and decimation. ADC_RESOLUTION_CUSTOM ADC 16-bit result register for use with averaging. When using this mode the ADC AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 55 Enum value Description result register will be set to 16-bit wide, and the number of samples to accumulate and the division factor is configured by the adc_config::accumulate_samples and adc_config::divide_result members in the configuration struct. 2.6.4.13 Enum adc_window_mode Enum for the possible window monitor modes for the ADC. Table 2-54. Members Enum value Description ADC_WINDOW_MODE_DISABLE No window mode. ADC_WINDOW_MODE_ABOVE_LOWER RESULT > WINLT. ADC_WINDOW_MODE_BELOW_UPPER RESULT < WINUT. ADC_WINDOW_MODE_BETWEEN WINLT < RESULT < WINUT. ADC_WINDOW_MODE_BETWEEN_INVERTED !(WINLT < RESULT < WINUT). 2.7 Extra Information for ADC Driver 2.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 2.7.2 Acronym Description ADC Analog-to-Digital Converter DAC Digital-to-Analog Converter LSB Least Significant Bit MSB Most Significant Bit DMA Direct Memory Access Dependencies This driver has the following dependencies: ● 2.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 2.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAMR21 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 56 Changelog Added support for SAMD21 and new DMA quick start guide Added ADC calibration constant loading from the device signature row when the module is initialized Initial Release 2.8 Examples for ADC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Analog to Digital Converter Driver (ADC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_adc_basic_use_case ● asfdoc_sam0_adc_dma_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 57 3. SAM Brown Out Detector Driver (BOD) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Brown Out Detector (BOD) modules, to detect and respond to under-voltage events and take an appropriate action. The following peripherals are used by this module: ● SYSCTRL (System Control) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 The outline of this documentation is as follows: 3.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 3.2 Module Overview The SAM devices contain a number of Brown Out Detector (BOD) modules. Each BOD monitors the supply voltage for any dips that go below the set threshold for the module. In case of a BOD detection the BOD will either reset the system or raise a hardware interrupt so that a safe power-down sequence can be attempted. 3.3 Special Considerations The time between a BOD interrupt being raised and a failure of the processor to continue executing (in the case of a core power failure) is system specific; care must be taken that all critical BOD detection events can complete within the amount of time available. 3.4 Extra Information For extra information, see Extra Information for BOD Driver. This includes: ● Acronyms ● Dependencies ● Errata ● Module History 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 58 3.5 Examples For a list of examples related to this driver, see Examples for BOD Driver. 3.6 API Overview 3.6.1 Structure Definitions 3.6.1.1 Struct bod_config Configuration structure for a BOD module. Table 3-1. Members Type Name Description enum bod_action action Action to perform when a low power detection is made. bool hysteresis If true, enables detection hysteresis. uint8_t level BOD level to trigger at (see electrical section of device datasheet). enum bod_mode mode Sampling configuration mode for the BOD. enum bod_prescale prescaler Input sampler clock prescaler factor, to reduce the 1KHz clock from the ULP32K to lower the sampling rate of the BOD. bool run_in_standby If true, the BOD is kept enabled and sampled during device sleep. 3.6.2 Function Definitions 3.6.2.1 Configuration and Initialization Function bod_get_config_defaults() Get default BOD configuration. void bod_get_config_defaults( struct bod_config *const conf) The default BOD configuration is: ● Clock prescaler set to divide the input clock by two ● Continuous mode ● Reset on BOD detect ● Hysteresis enabled ● BOD level 0x12 ● BOD kept enabled during device sleep AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 59 Table 3-2. Parameters Data direction Parameter name Description [out] conf BOD configuration struct to set to default settings Function bod_set_config() Configure a Brown Out Detector module. enum status_code bod_set_config( const enum bod bod_id, struct bod_config *const conf) 2 Support and FAQ: visit Atmel Support Configures a given BOD module with the settings stored in the given configuration structure. Table 3-3. Parameters Data direction Parameter name Description [in] bod_id BOD module to configure [in] conf Configuration settings to use for the specified BOD Table 3-4. Return Values Return value Description STATUS_OK Operation completed successfully STATUS_ERR_INVALID_ARG An invalid BOD was supplied STATUS_ERR_INVALID_OPTION The requested BOD level was outside the acceptable range Function bod_enable() Enables a configured BOD module. enum status_code bod_enable( const enum bod bod_id) Enables the specified BOD module that has been previously configured. Table 3-5. Parameters Returns Data direction Parameter name Description [in] bod_id BOD module to enable Error code indicating the status of the enable operation. Table 3-6. Return Values 2 Return value Description STATUS_OK If the BOD was successfully enabled http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 60 Return value Description STATUS_ERR_INVALID_ARG An invalid BOD was supplied Function bod_disable() Disables an enabled BOD module. enum status_code bod_disable( const enum bod bod_id) Disables the specified BOD module that was previously enabled. Table 3-7. Parameters Data direction Parameter name Description [in] bod_id BOD module to disable Returns Error code indicating the status of the disable operation. Table 3-8. Return Values Return value Description STATUS_OK If the BOD was successfully disabled STATUS_ERR_INVALID_ARG An invalid BOD was supplied Function bod_is_detected() Checks if a specified BOD low voltage detection has occurred. bool bod_is_detected( const enum bod bod_id) Determines if a specified BOD has detected a voltage lower than its configured threshold. Table 3-9. Parameters Data direction Parameter name Description [in] bod_id BOD module to check Returns Detection status of the specified BOD. Table 3-10. Return Values Return value Description true If the BOD has detected a low voltage condition false If the BOD has not detected a low voltage condition Function bod_clear_detected() Clears the low voltage detection state of a specified BOD. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 61 void bod_clear_detected( const enum bod bod_id) Clears the low voltage condition of a specified BOD module, so that new low voltage conditions can be detected. Table 3-11. Parameters Data direction Parameter name Description [in] bod_id BOD module to clear 3.6.3 Enumeration Definitions 3.6.3.1 Enum bod List of possible BOD controllers within the device. Table 3-12. Members 3.6.3.2 Enum value Description BOD_BOD33 BOD33 External I/O voltage. Enum bod_action List of possible BOD actions when a BOD module detects a brown out condition. Table 3-13. Members 3.6.3.3 Enum value Description BOD_ACTION_NONE A BOD detect will do nothing, and the BOD state must be polled. BOD_ACTION_RESET A BOD detect will reset the device. BOD_ACTION_INTERRUPT A BOD detect will fire an interrupt. Enum bod_mode List of possible BOD module voltage sampling modes. Table 3-14. Members 3.6.3.4 Enum value Description BOD_MODE_CONTINUOUS BOD will sample the supply line continuously. BOD_MODE_SAMPLED BOD will use the BOD sampling clock (1KHz) to sample the supply line. Enum bod_prescale List of possible BOD controller prescaler values, to reduce the sampling speed of a BOD to lower the power consumption. Table 3-15. Members Enum value Description BOD_PRESCALE_DIV_2 Divide input prescaler clock by 2. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 62 Enum value Description BOD_PRESCALE_DIV_4 Divide input prescaler clock by 4. BOD_PRESCALE_DIV_8 Divide input prescaler clock by 8. BOD_PRESCALE_DIV_16 Divide input prescaler clock by 16. BOD_PRESCALE_DIV_32 Divide input prescaler clock by 32. BOD_PRESCALE_DIV_64 Divide input prescaler clock by 64. BOD_PRESCALE_DIV_128 Divide input prescaler clock by 128. BOD_PRESCALE_DIV_256 Divide input prescaler clock by 256. BOD_PRESCALE_DIV_512 Divide input prescaler clock by 512. BOD_PRESCALE_DIV_1024 Divide input prescaler clock by 1024. BOD_PRESCALE_DIV_2048 Divide input prescaler clock by 2048. BOD_PRESCALE_DIV_4096 Divide input prescaler clock by 4096. BOD_PRESCALE_DIV_8192 Divide input prescaler clock by 8192. BOD_PRESCALE_DIV_16384 Divide input prescaler clock by 16384. BOD_PRESCALE_DIV_32768 Divide input prescaler clock by 32768 BOD_PRESCALE_DIV_65536 Divide input prescaler clock by 65536. 3.7 Extra Information for BOD Driver 3.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 3.7.2 Acronym Definition BOD Brown out detector Dependencies This driver has the following dependencies: ● 3.7.3 None Errata There are no errata related to this driver. 3.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAMD21 and removed BOD12 reference Initial Release 3.8 Examples for BOD Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Brown Out Detector Driver (BOD). QSGs are simple examples with step-by-step instructions to configure and use this driver in a AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 63 selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 3.8.1 ● asfdoc_sam0_bod_basic_use_case ● Application Use Case for BOD - Application Application Use Case for BOD - Application The preferred method of setting BOD33 levels and settings is trough the fuses. When it is desirable to set it in software, see the below use case. In this use case, a new BOD33 level might be set in SW if the clock settings are adjusted up after a battery has charged to a higher level. When the battery discharges, the chip will reset when the battery level is below SW BOD33 level. Now the chip will run at a lower clock rate and the BOD33 level from fuse. The chip should always measure the voltage before adjusting the frequency up. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 64 4. SAM Digital-to-Analog Driver (DAC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the conversion of digital values to analog voltage. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● DAC (Digital to Analog Converter) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM D10/D11 The outline of this documentation is as follows: 4.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 4.2 Module Overview The Digital-to-Analog converter converts a digital value to analog voltage. The SAM DAC module has one channel with 10-bit resolution, and is capable of converting up to 350k samples per second (ksps). A common use of DAC is to generate audio signals by connecting the DAC output to a speaker, or to generate a reference voltage; either for an external circuit or an internal peripheral such as the Analog Comparator. After being set up, the DAC will convert new digital values written to the conversion data register (DATA) to an analog value either on the VOUT pin of the device, or internally for use as an input to the AC, ADC, and other analog modules. Writing the DATA register will start a new conversion. It is also possible to trigger the conversion from the event system. A simplified block diagram of the DAC can be seen in Figure 4-1: DAC Block Diagram on page 66. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 65 Figure 4-1. DAC Block Diagram 4.2.1 Conversion Range The conversion range is between GND and the selected voltage reference. Available voltage references are: Note ● AVCC voltage reference ● Internal 1V reference (INT1V) ● External voltage reference (AREF) Internal references will be enabled by the driver, but not disabled. Any reference not used by the application should be disabled by the application. The output voltage from a DAC channel is given as: (4.1) 4.2.2 Conversion The digital value written to the conversion data register (DATA) will be converted to an analog value. Writing the DATA register will start a new conversion. It is also possible to write the conversion data to the DATABUF register, the writing of the DATA register can then be triggered from the event system, which will load the value from DATABUF to DATA. 4.2.3 Analog Output The analog output value can be output to either the VOUT pin or internally, but not both at the same time. 4.2.3.1 External Output The output buffer must be enabled in order to drive the DAC output to the VOUT pin. Due to the output buffer, the DAC has high drive strength, and is capable of driving both resistive and capacitive loads, as well as loads which combine both. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 66 4.2.3.2 Internal Output The analog value can be internally available for use as input to the AC or ADC modules. 4.2.4 Events Events generation and event actions are configurable in the DAC. The DAC has one event line input and one event output: Start Conversion and Data Buffer Empty. If the Start Conversion input event is enabled in the module configuration, an incoming event will load data from the data buffer to the data register and start a new conversion. This method synchronizes conversions with external events (such as those from a timer module) and ensures regular and fixed conversion intervals. If the Data Buffer Empty output event is enabled in the module configuration, events will be generated when the DAC data buffer register becomes empty and new data can be loaded to the buffer. Note 4.2.5 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Left and Right Adjusted Values The 10-bit input value to the DAC is contained in a 16-bit register. This can be configured to be either left or right adjusted. In Figure 4-2: Left and Right Adjusted Values on page 67 both options are shown, and the position of the most (MSB) and the least (LSB) significant bits are indicated. The unused bits should always be written to zero. Figure 4-2. Left and Right Adjusted Values Le ft a d ju s t e d . MSB Rig h t a d ju s t e d . LS B MSB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DATA[9 :0 ] 4.2.6 LS B 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DATA[9 :0 ] Clock Sources The clock for the DAC interface (CLK_DAC) is generated by the Power Manager. This clock is turned on by default, and can be enabled and disabled in the Power Manager. Additionally, an asynchronous clock source (GCLK_DAC) is required. These clocks are normally disabled by default. The selected clock source must be enabled in the Power Manager before it can be used by the DAC. The DAC core operates asynchronously from the user interface and peripheral bus. As a consequence, the DAC needs two clock cycles of both CLK_DAC and GCLK_DAC to synchronize the values written to some of the control and data registers. The oscillator source for the GCLK_DAC clock is selected in the System Control Interface (SCIF). 4.3 Special Considerations 4.3.1 Output Driver The DAC can only do conversions in Active or Idle modes. However, if the output buffer is enabled it will draw current even if the system is in sleep mode. Therefore, always make sure that the output buffer is not enabled when it is not needed, to ensure minimum power consumption. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 67 4.3.2 Conversion Time DAC conversion time is approximately 2.85#s. The user must ensure that new data is not written to the DAC before the last conversion is complete. Conversions should be triggered by a periodic event from a Timer/Counter or another peripheral. 4.4 Extra Information For extra information, see Extra Information for DAC Driver. This includes: 4.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for DAC Driver. 4.6 API Overview 4.6.1 Variable and Type Definitions 4.6.1.1 Type dac_callback_t typedef void(* dac_callback_t )(uint8_t channel) Type definition for a DAC module callback function. 4.6.2 Structure Definitions 4.6.2.1 Struct dac_chan_config Configuration for a DAC channel. This structure should be initialized by the dac_chan_get_config_defaults() function before being modified by the user application. 4.6.2.2 Struct dac_config Configuration structure for a DAC instance. This structure should be initialized by the dac_get_config_defaults() function before being modified by the user application. Table 4-1. Members Type Name Description enum gclk_generator clock_source GCLK generator used to clock the peripheral. bool left_adjust Left adjusted data. enum dac_output output Select DAC output. enum dac_reference reference Reference voltage. bool run_in_standby The DAC behaves as in normal mode when the chip enters STANDBY sleep mode. bool voltage_pump_disable Voltage pump disable. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 68 4.6.2.3 Struct dac_events Event flags for the DAC module. This is used to enable and disable events via dac_enable_events() and dac_disable_events(). Table 4-2. Members 4.6.2.4 Type Name Description bool generate_event_on_buffer_empty Enable event generation on data buffer empty. bool on_event_start_conversion Start a new DAC conversion. Struct dac_module DAC software instance structure, used to retain software state information of an associated hardware module instance. Note The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. 4.6.3 Macro Definitions 4.6.3.1 DAC Status Flags DAC status flags, returned by dac_get_status() and cleared by dac_clear_status(). Macro DAC_STATUS_CHANNEL_0_EMPTY #define DAC_STATUS_CHANNEL_0_EMPTY (1UL << 0) Data Buffer Empty Channel 0 - Set when data is transferred from DATABUF to DATA by a start conversion event and DATABUF is ready for new data. Macro DAC_STATUS_CHANNEL_0_UNDERRUN #define DAC_STATUS_CHANNEL_0_UNDERRUN (1UL << 1) Under-run Channel 0 - Set when a start conversion event occurs when DATABUF is empty. 4.6.3.2 Macro DAC_TIMEOUT #define DAC_TIMEOUT 0xFFFF Define DAC features set according to different device family. 4.6.4 Function Definitions 4.6.4.1 Configuration and Initialization Function dac_is_syncing() Determines if the hardware module(s) are currently synchronizing to the bus. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 69 bool dac_is_syncing( struct dac_module *const dev_inst) Checks to see if the underlying hardware peripheral module(s) are currently synchronizing across multiple clock domains to the hardware bus, This function can be used to delay further operations on a module until such time that it is ready, to prevent blocking delays for synchronization in the user application. Table 4-3. Parameters Data direction Parameter name Description [in] dev_inst Pointer to the DAC software instance struct Returns Synchronization status of the underlying hardware module(s). Table 4-4. Return Values Return value Description true if the module synchronization is ongoing false if the module has completed synchronization Function dac_get_config_defaults() Initializes a DAC configuration structure to defaults. void dac_get_config_defaults( struct dac_config *const config) Initializes a given DAC configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. The default configuration is as follows: ● 1V from internal bandgap reference ● Drive the DAC output to the VOUT pin ● Right adjust data ● GCLK generator 0 (GCLK main) clock source ● The output buffer is disabled when the chip enters STANDBY sleep mode Table 4-5. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function dac_init() Initialize the DAC device struct. enum status_code dac_init( struct dac_module *const dev_inst, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 70 Dac *const module, struct dac_config *const config) Use this function to initialize the Digital to Analog Converter. Resets the underlying hardware module and configures it. Note The DAC channel must be configured separately. Table 4-6. Parameters Data direction Parameter name Description [out] module_inst Pointer to the DAC software instance struct [in] module Pointer to the DAC module instance [in] config Pointer to the config struct, created by the user application Returns Status of initialization. Table 4-7. Return Values Return value Description STATUS_OK Module initiated correctly STATUS_ERR_DENIED If module is enabled STATUS_BUSY If module is busy resetting Function dac_reset() Resets the DAC module. void dac_reset( struct dac_module *const dev_inst) This function will reset the DAC module to its power on default values and disable it. Table 4-8. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct Function dac_enable() Enable the DAC module. void dac_enable( struct dac_module *const dev_inst) Enables the DAC interface and the selected output. If any internal reference is selected it will be enabled. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 71 Table 4-9. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct Function dac_disable() Disable the DAC module. void dac_disable( struct dac_module *const dev_inst) Disables the DAC interface and the output buffer. Table 4-10. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct Function dac_enable_events() Enables a DAC event input or output. void dac_enable_events( struct dac_module *const module_inst, struct dac_events *const events) Enables one or more input or output events to or from the DAC module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 4-11. Parameters Data direction Parameter name Description [in] module_inst Software instance for the DAC peripheral [in] events Struct containing flags of events to enable Function dac_disable_events() Disables a DAC event input or output. void dac_disable_events( struct dac_module *const module_inst, struct dac_events *const events) Disables one or more input or output events to or from the DAC module. See here for a list of events this module supports. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 72 Note Events cannot be altered while the module is enabled. Table 4-12. Parameters 4.6.4.2 Data direction Parameter name Description [in] module_inst Software instance for the DAC peripheral [in] events Struct containing flags of events to disable Configuration and Initialization (Channel) Function dac_chan_get_config_defaults() Initializes a DAC channel configuration structure to defaults. void dac_chan_get_config_defaults( struct dac_chan_config *const config) Initializes a given DAC channel configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. The default configuration is as follows: ● Start Conversion Event Input enabled ● Start Data Buffer Empty Event Output disabled Table 4-13. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function dac_chan_set_config() Writes a DAC channel configuration to the hardware module. void dac_chan_set_config( struct dac_module *const dev_inst, const enum dac_channel channel, struct dac_chan_config *const config) Writes a given channel configuration to the hardware module. Note The DAC device instance structure must be initialized before calling this function. Table 4-14. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel Channel to configure AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 73 Data direction Parameter name Description [in] config Pointer to the configuration struct Function dac_chan_enable() Enable a DAC channel. void dac_chan_enable( struct dac_module *const dev_inst, enum dac_channel channel) Enables the selected DAC channel. Table 4-15. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel Channel to enable Function dac_chan_disable() Disable a DAC channel. void dac_chan_disable( struct dac_module *const dev_inst, enum dac_channel channel) Disables the selected DAC channel. Table 4-16. Parameters 4.6.4.3 Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel Channel to disable Channel Data Management Function dac_chan_write() Write to the DAC. enum status_code dac_chan_write( struct dac_module *const dev_inst, enum dac_channel channel, const uint16_t data) This function writes to the DATA or DATABUF register. If the conversion is not event-triggered, the data will be written to the DATA register and the conversion will start. If the conversion is event-triggered, the data will be written to DATABUF and transferred to the DATA register and converted when a Start Conversion Event is issued. Conversion data must be right or left adjusted according to configuration settings. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 74 Note To be event triggered, the enable_start_on_event must be enabled in the configuration. Table 4-17. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct [in] channel DAC channel to write to [in] data Conversion data Returns Status of the operation. Table 4-18. Return Values Return value Description STATUS_OK If the data was written Function dac_chan_write_buffer_wait() Write to the DAC. enum status_code dac_chan_write_buffer_wait( struct dac_module *const module_inst, enum dac_channel channel, uint16_t * buffer, uint32_t length) This function converts a specific number of digital data. The conversion should be event-triggered, the data will be written to DATABUF and transferred to the DATA register and converted when a Start Conversion Event is issued. Conversion data must be right or left adjusted according to configuration settings. Note To be event triggered, the enable_start_on_event must be enabled in the configuration. Table 4-19. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct [in] channel DAC channel to write to [in] buffer Pointer to the digital data write buffer to be converted [in] length Length of the write buffer Status of the operation. Table 4-20. Return Values Return value Description STATUS_OK If the data was written or no data conversion required AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 75 4.6.4.4 Return value Description STATUS_ERR_UNSUPPORTED_DEV The DAC is not configured as using event trigger. STATUS_BUSY The DAC is busy to convert. Status Management Function dac_get_status() Retrieves the current module status. uint32_t dac_get_status( struct dac_module *const module_inst) Checks the status of the module and returns it as a bitmask of status flags. Table 4-21. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct Returns Bitmask of status flags. Table 4-22. Return Values Return value Description DAC_STATUS_CHANNEL_0_EMPTY Data has been transferred from DATABUF to DATA by a start conversion event and DATABUF is ready for new data. DAC_STATUS_CHANNEL_0_UNDERRUN A start conversion event has occurred when DATABUF is empty Function dac_clear_status() Clears a module status flag. void dac_clear_status( struct dac_module *const module_inst, uint32_t status_flags) Clears the given status flag of the module. Table 4-23. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct [in] status_flags Bit mask of status flags to clear AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 76 4.6.4.5 Callback Configuration and Initialization Function dac_chan_write_buffer_job() Convert a specific number digital data to analog through DAC. enum status_code dac_chan_write_buffer_job( struct dac_module *const module_inst, const enum dac_channel channel, uint16_t * buffer, uint32_t buffer_size) This function will perform a conversion of specific number of digital data. The conversion should be event-triggered, the data will be written to DATABUF and transferred to the DATA register and converted when a Start Conversion Event is issued. Conversion data must be right or left adjusted according to configuration settings. Note To be event triggered, the enable_start_on_event must be enabled in the configuration. Table 4-24. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct [in] channel DAC channel to write to [in] buffer Pointer to the digital data write buffer to be converted [in] length Size of the write buffer Status of the operation. Table 4-25. Return Values Return value Description STATUS_OK If the data was written STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. STATUS_BUSY The DAC is busy to accept new job. Function dac_chan_write_job() Convert one digital data job. enum status_code dac_chan_write_job( struct dac_module *const module_inst, const enum dac_channel channel, uint16_t data) This function will perform a conversion of specfic number of digital data. The conversion is event-triggered, the data will be written to DATABUF and transferred to the DATA register and converted when a Start Conversion Event is issued. Conversion data must be right or left adjusted according to configuration settings. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 77 Note To be event triggered, the enable_start_on_event must be enabled in the configuration. Table 4-26. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software device struct [in] channel DAC channel to write to [in] data Digital data to be converted Returns Status of the operation. Table 4-27. Return Values Return value Description STATUS_OK If the data was written STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. STATUS_BUSY The DAC is busy to accept new job. Function dac_register_callback() Registers an asynchronous callback function with the driver. enum status_code dac_register_callback( struct dac_module *const module, const enum dac_channel channel, const dac_callback_t callback, const enum dac_callback type) Registers an asynchronous callback with the DAC driver, fired when a callback condition occurs. Table 4-28. Parameters Returns Data direction Parameter name Description [in, out] module_inst Pointer to the DAC software instance struct [in] callback Pointer to the callback function to register [in] channel Logical channel to register callback function [in] type Type of callback function to register Status of the registration operation. Table 4-29. Return Values Return value Description STATUS_OK The callback was registered successfully. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 78 Return value Description STATUS_ERR_INVALID_ARG If an invalid callback type was supplied. STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. Function dac_unregister_callback() Unregisters an asynchronous callback function with the driver. enum status_code dac_unregister_callback( struct dac_module *const module, const enum dac_channel channel, const enum dac_callback type) Unregisters an asynchronous callback with the DAC driver, removing it from the internal callback registration table. Table 4-30. Parameters Returns Data direction Parameter name Description [in, out] module_inst Pointer to the DAC software instance struct [in] channel Logical channel to unregister callback function [in] type Type of callback function to unregister Status of the de-registration operation. Table 4-31. Return Values 4.6.4.6 Return value Description STATUS_OK The callback was unregistered successfully. STATUS_ERR_INVALID_ARG If an invalid callback type was supplied. STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. Callback Enabling and Disabling (Channel) Function dac_chan_enable_callback() Enables asynchronous callback generation for a given channel and type. enum status_code dac_chan_enable_callback( struct dac_module *const module, const enum dac_channel channel, const enum dac_callback type) Enables asynchronous callbacks for a given logical DAC channel and type. This must be called before a DAC channel will generate callback events. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 79 Table 4-32. Parameters Data direction Parameter name Description [in, out] dac_module Pointer to the DAC software instance struct [in] channel Logical channel to enable callback function [in] type Type of callback function callbacks to enable Returns Status of the callback enable operation. Table 4-33. Return Values Return value Description STATUS_OK The callback was enabled successfully. STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. Function dac_chan_disable_callback() Disables asynchronous callback generation for a given channel and type. enum status_code dac_chan_disable_callback( struct dac_module *const module, const enum dac_channel channel, const enum dac_callback type) Disables asynchronous callbacks for a given logical DAC channel and type. Table 4-34. Parameters Returns Data direction Parameter name Description [in, out] dac_module Pointer to the DAC software instance struct [in] channel Logical channel to disable callback function [in] type Type of callback function callbacks to disable Status of the callback disable operation. Table 4-35. Return Values Return value Description STATUS_OK The callback was disabled successfully. STATUS_ERR_UNSUPPORTED_DEV If a callback that requires event driven mode was specified with a DAC instance configured in non-event mode. Function dac_chan_get_job_status() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 80 Gets the status of a job. enum status_code dac_chan_get_job_status( struct dac_module * module_inst, const enum dac_channel channel) Gets the status of an ongoing or the last job. Table 4-36. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel Logical channel to enable callback function Returns Status of the job. Function dac_chan_abort_job() Aborts an ongoing job. void dac_chan_abort_job( struct dac_module * module_inst, const enum dac_channel channel) Aborts an ongoing job. Table 4-37. Parameters 4.6.4.7 Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel Logical channel to enable callback function Configuration and Initialization (Channel) Function dac_chan_enable_output_buffer() Enable the output buffer. void dac_chan_enable_output_buffer( struct dac_module *const dev_inst, const enum dac_channel channel) Enables the output buffer and drives the DAC output to the VOUT pin. Table 4-38. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel DAC channel to alter AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 81 Function dac_chan_disable_output_buffer() Disable the output buffer. void dac_chan_disable_output_buffer( struct dac_module *const dev_inst, const enum dac_channel channel) Disables the output buffer. Note The output buffer(s) should be disabled when a channel's output is not currently needed, as it will draw current even if the system is in sleep mode. Table 4-39. Parameters Data direction Parameter name Description [in] module_inst Pointer to the DAC software instance struct [in] channel DAC channel to alter 4.6.5 Enumeration Definitions 4.6.5.1 Enum dac_callback Enum for the possible callback types for the DAC module. Table 4-40. Members 4.6.5.2 Enum value Description DAC_CALLBACK_DATA_EMPTY Callback type for when a DAC channel data empty condition occurs (requires event triggered mode). DAC_CALLBACK_DATA_UNDERRUN Callback type for when a DAC channel data under-run condition occurs (requires event triggered mode). DAC_CALLBACK_TRANSFER_COMPLETE Callback type for when a DAC channel write buffer job complete. (requires event triggered mode). Enum dac_channel Enum for the DAC channel selection. Table 4-41. Members 4.6.5.3 Enum value Description DAC_CHANNEL_0 DAC output channel 0. Enum dac_output Enum for the DAC output selection. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 82 Table 4-42. Members 4.6.5.4 Enum value Description DAC_OUTPUT_EXTERNAL DAC output to VOUT pin DAC_OUTPUT_INTERNAL DAC output as internal reference DAC_OUTPUT_NONE No output Enum dac_reference Enum for the possible reference voltages for the DAC. Table 4-43. Members Enum value Description DAC_REFERENCE_INT1V 1V from the internal band-gap reference. DAC_REFERENCE_AVCC Analog VCC as reference. DAC_REFERENCE_AREF External reference on AREF. 4.7 Extra Information for DAC Driver 4.7.1 Acronyms The table below presents the acronyms used in this module: 4.7.2 Acronym Description ADC Analog-to-Digital Converter AC Analog Comparator DAC Digital-to-Analog Converter LSB Least Significant Bit MSB Most Significant Bit DMA Direct Memory Access Dependencies This driver has the following dependencies: ● 4.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 4.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added new configuration parameters databuf_protection_bypass, voltage_pump_disable. Added new callback functions dac_chan_write_buffer_wait, dac_chan_write_buffer_job, dac_chan_write_job, dac_get_job_status, dac_abort_job and new callback type DAC_CALLBACK_TRANSFER_COMPLETE for DAC conversion job Initial Release AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 83 4.8 Examples for DAC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Digital-to-Analog Driver (DAC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 4.8.1 ● Quick Start Guide for DAC - Basic ● Quick Start Guide for DAC - Callback ● Quick Start Guide for Using DMA with ADC/DAC Quick Start Guide for DAC - Basic In this use case, the DAC will be configured with the following settings: 4.8.1.1 ● Analog VCC as reference ● Internal output disabled ● Drive the DAC output to the VOUT pin ● Right adjust data ● The output buffer is disabled when the chip enters STANDBY sleep mode Quick Start Prerequisites There are no special setup requirements for this use-case. Code Add to the main application source file, outside of any functions: struct dac_module dac_instance; Copy-paste the following setup code to your user application: void configure_dac(void) { struct dac_config config_dac; dac_get_config_defaults(&config_dac); } dac_init(&dac_instance, DAC, &config_dac); void configure_dac_channel(void) { struct dac_chan_config config_dac_chan; dac_chan_get_config_defaults(&config_dac_chan); dac_chan_set_config(&dac_instance, DAC_CHANNEL_0, &config_dac_chan); } dac_chan_enable(&dac_instance, DAC_CHANNEL_0); Add to user application initialization (typically the start of main()): configure_dac(); configure_dac_channel(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 84 Workflow 1. Create a module software instance structure for the DAC module to store the DAC driver state while it is in use. struct dac_module dac_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the DAC module. a. Create a DAC module configuration struct, which can be filled out to adjust the configuration of a physical DAC peripheral. struct dac_config config_dac; b. Initialize the DAC configuration struct with the module's default values. dac_get_config_defaults(&config_dac); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Configure the DAC channel. a. Create a DAC channel configuration struct, which can be filled out to adjust the configuration of a physical DAC output channel. struct dac_chan_config config_dac_chan; b. Initialize the DAC channel configuration struct with the module's default values. dac_chan_get_config_defaults(&config_dac_chan); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Configure the DAC channel with the desired channel settings. dac_chan_set_config(&dac_instance, DAC_CHANNEL_0, &config_dac_chan); d. Enable the DAC channel so that it can output a voltage. dac_chan_enable(&dac_instance, DAC_CHANNEL_0); 4. Enable the DAC module. dac_enable(&dac_instance); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 85 4.8.1.2 Use Case Code Copy-paste the following code to your user application: uint16_t i = 0; while (1) { dac_chan_write(&dac_instance, DAC_CHANNEL_0, i); if (++i == 0x3FF) { i = 0; } } Workflow 1. Create a temporary variable to track the current DAC output value. uint16_t i = 0; 2. Enter an infinite loop to continuously output new conversion values to the DAC. while (1) { 3. Write the next conversion value to the DAC, so that it will be output on the device's DAC analog output pin. dac_chan_write(&dac_instance, DAC_CHANNEL_0, i); 4. Increment and wrap the DAC output conversion value, so that a ramp pattern will be generated. if (++i == 0x3FF) { i = 0; } 4.8.2 Quick Start Guide for DAC - Callback In this use case, the DAC will be convert 16 samples using interrupt driven conversion. When all samples have been sampled, a callback will be called that signals the main application that conversion is compete. The DAC will be set up as follows: 4.8.2.1 ● Analog VCC as reference ● Internal output disabled ● Drive the DAC output to the VOUT pin ● Right adjust data ● The output buffer is disabled when the chip enters STANDBY sleep mode ● DAC conversion is started with RTC overflow event Setup Prerequisites There are no special setup requirements for this use-case. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 86 Code Add to the main application source file, outside of any functions: #define DATA_LENGTH (16) struct dac_module dac_instance; struct rtc_module rtc_instance; struct events_resource event_dac; static volatile bool transfer_is_done = false; static uint16_t dac_data[DATA_LENGTH]; Callback function: void dac_callback(uint8_t channel) { UNUSED(channel); } transfer_is_done = true; Copy-paste the following setup code to your user application: void configure_rtc_count(void) { struct rtc_count_events rtc_event; struct rtc_count_config config_rtc_count; rtc_count_get_config_defaults(&config_rtc_count); config_rtc_count.prescaler = RTC_COUNT_PRESCALER_DIV_1; config_rtc_count.mode = RTC_COUNT_MODE_16BIT; #ifdef FEATURE_RTC_CONTINUOUSLY_UPDATED config_rtc_count.continuously_update = true; #endif rtc_count_init(&rtc_instance, RTC, &config_rtc_count); rtc_event.generate_event_on_overflow = true; rtc_count_enable_events(&rtc_instance, &rtc_event); } rtc_count_enable(&rtc_instance); void configure_dac(void) { struct dac_config config_dac; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 87 dac_get_config_defaults(&config_dac); #if (SAML21) dac_instance.start_on_event[DAC_CHANNEL_0] = true; #else dac_instance.start_on_event = true; #endif dac_init(&dac_instance, DAC, &config_dac); struct dac_events events = #if (SAML21) { .on_event_chan0_start_conversion = true }; #else { .on_event_start_conversion = true }; #endif } dac_enable_events(&dac_instance, &events); void configure_dac_channel(void) { struct dac_chan_config config_dac_chan; dac_chan_get_config_defaults(&config_dac_chan); dac_chan_set_config(&dac_instance, DAC_CHANNEL_0, &config_dac_chan); } dac_chan_enable(&dac_instance, DAC_CHANNEL_0); Define a data length variables and add to user application (typically the start of main()): uint32_t i; Add to user application initialization (typically the start of main()): configure_rtc_count(); rtc_count_set_period(&rtc_instance, 1); configure_dac(); configure_dac_channel(); dac_enable(&dac_instance); configure_event_resource(); dac_register_callback(&dac_instance, DAC_CHANNEL_0, dac_callback,DAC_CALLBACK_TRANSFER_COMPLETE); dac_chan_enable_callback(&dac_instance, DAC_CHANNEL_0, DAC_CALLBACK_TRANSFER_COMPLETE); for (i = 0;i < DATA_LENGTH;i++) { dac_data[i] = 0xfff * i; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 88 } Workflow 1. Create a module software instance structure for the DAC module to store the DAC driver state while it is in use. struct dac_module dac_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. RTC module is used as the event trigger for DAC in this case, create a module software instance structure for the RTC module to store the RTC driver state. struct rtc_module rtc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 3. Create a buffer for the DAC samples to be converted by the driver. static uint16_t dac_data[DATA_LENGTH]; 4. Create a callback function that will be called when DAC completes convert job. void dac_callback(uint8_t channel) { UNUSED(channel); } 5. transfer_is_done = true; Configure the DAC module. a. Create a DAC module configuration struct, which can be filled out to adjust the configuration of a physical DAC peripheral. struct dac_config config_dac; b. Initialize the DAC configuration struct with the module's default values. dac_get_config_defaults(&config_dac); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Configure the DAC module with starting conversion on event. #if (SAML21) dac_instance.start_on_event[DAC_CHANNEL_0] = true; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 89 #else dac_instance.start_on_event = true; #endif d. Initialize the DAC module. dac_init(&dac_instance, DAC, &config_dac); e. Enable DAC start on conversion mode. struct dac_events events = #if (SAML21) { .on_event_chan0_start_conversion = true }; #else { .on_event_start_conversion = true }; #endif f. Enable DAC event. dac_enable_events(&dac_instance, &events); 6. Configure the DAC channel. a. Create a DAC channel configuration struct, which can be filled out to adjust the configuration of a physical DAC output channel. struct dac_chan_config config_dac_chan; b. Initialize the DAC channel configuration struct with the module's default values. dac_chan_get_config_defaults(&config_dac_chan); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Configure the DAC channel with the desired channel settings. dac_chan_set_config(&dac_instance, DAC_CHANNEL_0, &config_dac_chan); d. Enable the DAC channel so that it can output a voltage. dac_chan_enable(&dac_instance, DAC_CHANNEL_0); 7. Enable DAC module. dac_enable(&dac_instance); 8. Configure the RTC module. a. Create a RTC module event struct, which can be filled out to adjust the configuration of a physical RTC peripheral. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 90 struct rtc_count_events b. rtc_event; Create a RTC module configuration struct, which can be filled out to adjust the configuration of a physical RTC peripheral. struct rtc_count_config config_rtc_count; c. Initialize the RTC configuration struct with the module's default values. rtc_count_get_config_defaults(&config_rtc_count); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. d. Change the RTC module configuration to suit the application. config_rtc_count.prescaler = RTC_COUNT_PRESCALER_DIV_1; config_rtc_count.mode = RTC_COUNT_MODE_16BIT; #ifdef FEATURE_RTC_CONTINUOUSLY_UPDATED config_rtc_count.continuously_update = true; #endif e. Initialize the RTC module. rtc_count_init(&rtc_instance, RTC, &config_rtc_count); f. Configure the RTC module with overflow event. rtc_event.generate_event_on_overflow = true; g. Enable RTC module overflow event. rtc_count_enable_events(&rtc_instance, &rtc_event); h. Enable RTC module. rtc_count_enable(&rtc_instance); 9. Configure the Event resource. a. Create a event resource config struct, which can be filled out to adjust the configuration of a physical event peripheral. struct events_config event_config; b. Initialize the event configuration struct with the module's default values. events_get_config_defaults(&event_config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 91 Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Change the event module configuration to suit the application. event_config.generator event_config.edge_detect event_config.path event_config.clock_source d. = = = = EVSYS_ID_GEN_RTC_OVF; EVENTS_EDGE_DETECT_RISING; EVENTS_PATH_ASYNCHRONOUS; GCLK_GENERATOR_0; Allocate the event resource. events_allocate(&event_dac, &event_config); e. Attach the event resource with user DAC start. #if (SAML21) events_attach_user(&event_dac, EVSYS_ID_USER_DAC_START_0); #else events_attach_user(&event_dac, EVSYS_ID_USER_DAC_START); #endif 10. Register and enable the DAC Write Buffer Complete callback handler. a. Register the user-provided Write Buffer Complete callback function with the driver, so that it will be run when an asynchronous buffer write job completes. dac_register_callback(&dac_instance, DAC_CHANNEL_0, dac_callback,DAC_CALLBACK_TRANSFER_COMPLETE); b. Enable the Read Buffer Complete callback so that it will generate callbacks. dac_chan_enable_callback(&dac_instance, DAC_CHANNEL_0, DAC_CALLBACK_TRANSFER_COMPLETE); 4.8.2.2 Use Case Code Copy-paste the following code to your user application: dac_chan_write_buffer_job(&dac_instance, DAC_CHANNEL_0, dac_data, DATA_LENGTH); while (!transfer_is_done) { /* Wait for transfer done */ } while (1) { } Workflow 1. Start an DAC conversion and generate a callback when complete. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 92 dac_chan_write_buffer_job(&dac_instance, DAC_CHANNEL_0, dac_data, DATA_LENGTH); 2. Wait until the conversion is complete. while (!transfer_is_done) { /* Wait for transfer done */ } 3. Enter an infinite loop once the conversion is complete. while (1) { } 4.8.3 Quick Start Guide for Using DMA with ADC/DAC For this examples, see asfdoc_sam0_adc_dma_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 93 5. SAM Direct Memory Access Controller Driver (DMAC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the Direct Memory Access Controller(DMAC) module within the device. The DMAC can transfer data between memories and peripherals, and thus off-load these tasks from the CPU. The module supports peripheral to peripheral, peripheral to memory, memory to peripheral, and memory to memory transfers. The following peripherals are used by the DMAC Driver: ● DMAC (Direct Memory Access Controller) The following devices can use this module: ● Atmel | SMART SAM D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 5.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 5.2 Module Overview SAM devices with DMAC enables high data transfer rates with minimum CPU intervention and frees up CPU time. With access to all peripherals, the DMAC can handle automatic transfer of data to/from modules. It supports static and incremental addressing for both source and destination. The DMAC when used with Event System or peripheral triggers, provides a considerable advantage by reducing the power consumption and performing data transfer in the background. For example if the ADC is configured to generate an event, it can trigger the DMAC to transfer the data into another peripheral or into SRAM. The CPU can remain in sleep during this time to reduce power consumption. The DMAC module has 12 channels. The DMA channel operation can be suspended at any time by software, by events from event system, or after selectable descriptor execution. The operation can be resumed by software or by events from event system. The DMAC driver for SAM supports four types of transfers such as peripheral to peripheral, peripheral to memory, memory to peripheral, and memory to memory. The basic transfer unit is a beat which is defined as a single bus access. There can be multiple beats in a single block transfer and multiple block transfers in a DMA transaction. DMA transfer is based on descriptors, which holds transfer properties such as the source and destination addresses, transfer counter, and other additional transfer control information. The descriptors can be static or linked. When static, a single block transfer is performed. When linked, a number of transfer descriptors can be used to enable multiple block transfers within a single DMA transaction. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 94 The implementation of the DMA driver is based on the idea that DMA channel is a finite resource of entities with the same abilities. A DMA channel resource is able to move a defined set of data from a source address to destination address triggered by a transfer trigger. On the SAM devices there are 12 DMA resources available for allocation. Each of these DMA resources can trigger interrupt callback routines and peripheral events. The other main features are ● Selectable transfer trigger source ● Software ● Event System ● Peripheral ● Event input and output is supported for the four lower channels ● Four level channel priority ● Optional interrupt generation on transfer complete, channel error or channel suspend ● Supports multi-buffer or circular buffer mode by linking multiple descriptors ● Beat size configurable as 8-bit, 16-bit, or 32-bit A simplified block diagram of the DMA Resource can be seen in Figure 5-1: Module Overview on page 95. Figure 5-1. Module Overview Tr a n s fe r De s c r ip t o r In t e r r u p t Tr a n s fe r Tr ig g e r DM A Ch a n n e l E ve n t s 5.2.1 Driver Feature Macro Definition Driver Feature Macro Supported devices FEATURE_DMA_CHANNEL_STANDBY SAML21 Note 5.2.2 The specific features are only available in the driver when the selected device supports those features. Terminology Used in DMAC Transfers Name Description Beat It is a single bus access by the DMAC. Configurable as 8-bit, 16-bit, or 32-bit Burst It is a transfer of n-beats (n=1,4,8,16). For the DMAC module in SAM, the burst size is one beat. Arbitration takes place each time a burst transfer is completed AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 95 5.2.3 Name Description Block transfer A single block transfer is a configurable number of (1 to 64k) beat transfers DMA Channels The DMAC in each device consists of several DMA channels, which along with the transfer descriptors defines the data transfer properties. ● The transfer control descriptor defines the source and destination addresses, source and destination address increment settings, the block transfer count and event output condition selection ● Dedicated channel registers control the peripheral trigger source, trigger mode settings, event input actions, and channel priority level settings With a successful DMA resource allocation, a dedicated DMA channel will be assigned. The channel will be occupied until the DMA resource is freed. A DMA resource handle is used to identify the specific DMA resource. When there are multiple channels with active requests, the arbiter prioritizes the channels requesting access to the bus. 5.2.4 DMA Triggers DMA transfer can be started only when a DMA transfer request is acknowledged/granted by the arbiter. A transfer request can be triggered from software, peripheral, or an event. There are dedicated source trigger selections for each DMA channel usage. 5.2.5 DMA Transfer Descriptor The transfer descriptor resides in the SRAM and defines these channel properties. Field name Field width Descriptor Next Address 32 bits Destination Address 32 bits Source Address 32 bits Block Transfer Counter 16 bits Block Transfer Control 16 bits Before starting a transfer, at least one descriptor should be configured. After a successful allocation of a DMA channel, the transfer descriptor can be added with a call to dma_add_descriptor(). If there is a transfer descriptor already allocated to the DMA resource, the descriptor will be linked to the next descriptor address. 5.2.6 DMA Interrupts/Events Both an interrupt callback and an peripheral event can be triggered by the DMA transfer. Three types of callbacks are supported by the DMA driver: transfer complete, channel suspend, and transfer error. Each of these callback types can be registered and enabled for each channel independently through the DMA driver API. The DMAC module can also generate events on transfer complete. Event generation is enabled through the DMA channel, event channel configuration, and event user multiplexing is done through the events driver. The DMAC can generate events in the below cases: 5.3 ● When a block transfer is complete ● When each beat transfer within a block transfer is complete Special Considerations There are no special considerations for this module. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 96 5.4 Extra Information For extra information, see Extra Information for DMAC Driver. This includes: 5.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for DMAC Driver. 5.6 API Overview 5.6.1 Variable and Type Definitions 5.6.1.1 Type dma_callback_t typedef void(* dma_callback_t )(const struct dma_resource *const resource) Type definition for a DMA resource callback function. 5.6.1.2 Variable descriptor_section DmacDescriptor descriptor_section ExInitial description section. 5.6.2 Structure Definitions 5.6.2.1 Struct dma_descriptor_config DMA transfer descriptor configuration. When the source or destination address increment is enabled, the addresses stored into the configuration structure must correspond to the end of the transfer. Table 5-1. Members Type Name Description enum dma_beat_size beat_size Beat size is configurable as 8-bit, 16-bit, or 32-bit. enum dma_block_action block_action Action taken when a block transfer is completed. uint16_t block_transfer_count It is the number of beats in a block. This count value is decremented by one after each beat data transfer. bool descriptor_valid Descriptor valid flag used to identify whether a descriptor is valid or not. uint32_t destination_address Transfer destination address. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 97 5.6.2.2 Type Name Description bool dst_increment_enable Used for enabling the destination address increment. enum dma_event_output_selection event_output_selection This is used to generate an event on specific transfer action in a channel. Supported only in four lower channels. uint32_t next_descriptor_address Set to zero for static descriptors. This must have a valid memory address for linked descriptors. uint32_t source_address Transfer source address. bool src_increment_enable Used for enabling the source address increment. enum dma_step_selection step_selection This bit selects whether the source or destination address is using the step size settings. enum dma_address_increment_stepsize step_size The step size for source/ destination address increment. The next address is calculated as next_addr = addr + (2^step_size * beat size). Type Name Description bool event_output_enable Enable DMA event output. enum dma_event_input_action input_action Event input actions. Type Name Description dma_callback_t callback[] Array of callback functions for DMA transfer job. uint8_t callback_enable Bit mask for enabled callbacks. uint8_t channel_id Allocated DMA channel ID. DmacDescriptor * descriptor DMA transfer descriptor. enum status_code job_status Status of the last job. uint32_t transfered_size Transferred data size. Struct dma_events_config Configurations for DMA events. Table 5-2. Members 5.6.2.3 Struct dma_resource Structure for DMA transfer resource. Table 5-3. Members 5.6.2.4 Struct dma_resource_config DMA configurations for transfer. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 98 Table 5-4. Members Type Name Description struct dma_events_config event_config DMA events configurations. uint8_t peripheral_trigger DMA peripheral trigger index. enum dma_priority_level priority DMA transfer priority. enum dma_transfer_trigger_action trigger_action DMA trigger action. 5.6.3 Macro Definitions 5.6.3.1 Macro DMA_INVALID_CHANNEL #define DMA_INVALID_CHANNEL 0xff DMA invalid channel number. 5.6.4 Function Definitions 5.6.4.1 Function dma_abort_job() Abort a DMA transfer. void dma_abort_job( struct dma_resource * resource) This function will abort a DMA transfer. The DMA channel used for the DMA resource will be disabled. The block transfer count will be also calculated and written to the DMA resource structure. Note The DMA resource will not be freed after calling this function. The function dma_free() can be used to free an allocated resource. Table 5-5. Parameters 5.6.4.2 Data direction Parameter name Description [in, out] resource Pointer to the DMA resource Function dma_add_descriptor() Add a DMA transfer descriptor to a DMA resource. enum status_code dma_add_descriptor( struct dma_resource * resource, DmacDescriptor * descriptor) This function will add a DMA transfer descriptor to a DMA resource. If there was a transfer descriptor already allocated to the DMA resource, the descriptor will be linked to the next descriptor address. Table 5-6. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 99 Data direction Parameter name Description [in] descriptor Pointer to the transfer descriptor Table 5-7. Return Values 5.6.4.3 Return value Description STATUS_OK The descriptor is added to the DMA resource STATUS_BUSY The DMA resource was busy and the descriptor is not added Function dma_allocate() Allocate a DMA with configurations. enum status_code dma_allocate( struct dma_resource * resource, struct dma_resource_config * config) This function will allocate a proper channel for a DMA transfer request. Table 5-8. Parameters Data direction Parameter name Description [in, out] dma_resource Pointer to a DMA resource instance [in] transfer_config Configurations of the DMA transfer Returns Status of the allocation procedure. Table 5-9. Return Values 5.6.4.4 Return value Description STATUS_OK The DMA resource was allocated successfully STATUS_ERR_NOT_FOUND DMA resource allocation failed Function dma_descriptor_create() Create a DMA transfer descriptor with configurations. void dma_descriptor_create( DmacDescriptor * descriptor, struct dma_descriptor_config * config) This function will set the transfer configurations to the DMA transfer descriptor. Table 5-10. Parameters Data direction Parameter name Description [in] descriptor Pointer to the DMA transfer descriptor [in] config Pointer to the descriptor configuration structure AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 100 5.6.4.5 Function dma_descriptor_get_config_defaults() Initializes DMA transfer configuration with predefined default values. void dma_descriptor_get_config_defaults( struct dma_descriptor_config * config) This function will initialize a given DMA descriptor configuration structure to a set of known default values. This function should be called on any new instance of the configuration structure before being modified by the user application. The default configuration is as follows: ● Set the descriptor as valid ● Disable event output ● No block action ● Set beat size as byte ● Enable source increment ● Enable destination increment ● Step size is applied to the destination address ● Address increment is beat size multiplied by 1 ● Default transfer size is set to 0 ● Default source address is set to NULL ● Default destination address is set to NULL ● Default next descriptor not available Table 5-11. Parameters 5.6.4.6 Data direction Parameter name Description [out] config Pointer to the configuration Function dma_disable_callback() Disable a callback function for a dedicated DMA resource. void dma_disable_callback( struct dma_resource * resource, enum dma_callback_type type) Table 5-12. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource [in] type Callback function type AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 101 5.6.4.7 Function dma_enable_callback() Enable a callback function for a dedicated DMA resource. void dma_enable_callback( struct dma_resource * resource, enum dma_callback_type type) Table 5-13. Parameters 5.6.4.8 Data direction Parameter name Description [in] resource Pointer to the DMA resource [in] type Callback function type Function dma_free() Free an allocated DMA resource. enum status_code dma_free( struct dma_resource * resource) This function will free an allocated DMA resource. Table 5-14. Parameters Returns Data direction Parameter name Description [in, out] resource Pointer to the DMA resource Status of the free procedure. Table 5-15. Return Values 5.6.4.9 Return value Description STATUS_OK The DMA resource was freed successfully STATUS_BUSY The DMA resource was busy and can't be freed STATUS_ERR_NOT_INITIALIZED DMA resource was not initialized Function dma_get_config_defaults() Initializes config with predefined default values. void dma_get_config_defaults( struct dma_resource_config * config) This function will initialize a given DMA configuration structure to a set of known default values. This function should be called on any new instance of the configuration structure before being modified by the user application. The default configuration is as follows: ● Software trigger is used as the transfer trigger ● Priority level 0 ● Only software/event trigger AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 102 ● Requires a trigger for each transaction ● No event input /output ● DMA channel is disabled during sleep mode (if has the feature) Table 5-16. Parameters Data direction Parameter name Description [out] config Pointer to the configuration 5.6.4.10 Function dma_get_job_status() Get DMA resource status. enum status_code dma_get_job_status( struct dma_resource * resource) Table 5-17. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource Returns Status of the DMA resource. 5.6.4.11 Function dma_is_busy() Check if the given DMA resource is busy. bool dma_is_busy( struct dma_resource * resource) Table 5-18. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource Returns Status which indicates whether the DMA resource is busy. Table 5-19. Return Values Return value Description true The DMA resource has an on-going transfer false The DMA resource is not busy 5.6.4.12 Function dma_register_callback() Register a callback function for a dedicated DMA resource. void dma_register_callback( struct dma_resource * resource, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 103 dma_callback_t callback, enum dma_callback_type type) There are three types of callback functions, which can be registered: ● Callback for transfer complete ● Callback for transfer error ● Callback for channel suspend Table 5-20. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource [in] callback Pointer to the callback function [in] type Callback function type 5.6.4.13 Function dma_reset_descriptor() Reset DMA descriptor. void dma_reset_descriptor( struct dma_resource * resource) This function will clear the DESCADDR register of an allocated DMA resource. 5.6.4.14 Function dma_resume_job() Resume a suspended DMA transfer. void dma_resume_job( struct dma_resource * resource) This function try to resume a suspended transfer of a DMA resource. Table 5-21. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource 5.6.4.15 Function dma_start_transfer_job() Start a DMA transfer. enum status_code dma_start_transfer_job( struct dma_resource * resource) This function will start a DMA transfer through an allocated DMA resource. Table 5-22. Parameters Data direction Parameter name Description [in, out] resource Pointer to the DMA resource AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 104 Returns Status of the transfer start procedure. Table 5-23. Return Values Return value Description STATUS_OK The transfer was started successfully STATUS_BUSY The DMA resource was busy and the transfer was not started STATUS_ERR_INVALID_ARG Transfer size is 0 and transfer was not started 5.6.4.16 Function dma_suspend_job() Suspend a DMA transfer. void dma_suspend_job( struct dma_resource * resource) This function will request to suspend the transfer of the DMA resource. The channel is kept enabled, can receive transfer triggers (the transfer pending bit will be set), but will be removed from the arbitration scheme. The channel operation can be resumed by calling dma_resume_job(). Note This function sets the command to suspend the DMA channel associated with a DMA resource. The channel suspend interrupt flag indicates whether the transfer is truly suspended. Table 5-24. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource 5.6.4.17 Function dma_trigger_transfer() Will set a software trigger for resource. void dma_trigger_transfer( struct dma_resource * resource) This function is used to set a software trigger on the DMA channel associated with resource. If a trigger is already pending no new trigger will be generated for the channel. Table 5-25. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource 5.6.4.18 Function dma_unregister_callback() Unregister a callback function for a dedicated DMA resource. void dma_unregister_callback( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 105 struct dma_resource * resource, enum dma_callback_type type) There are three types of callback functions: ● Callback for transfer complete ● Callback for transfer error ● Callback for channel suspend The application can unregister any of the callback functions which are already registered and are no longer needed. Table 5-26. Parameters Data direction Parameter name Description [in] resource Pointer to the DMA resource [in] type Callback function type 5.6.4.19 Function dma_update_descriptor() Update DMA descriptor. void dma_update_descriptor( struct dma_resource * resource, DmacDescriptor * descriptor) This function can update the descriptor of an allocated DMA resource. 5.6.5 Enumeration Definitions 5.6.5.1 Enum dma_address_increment_stepsize Address increment step size. These bits select the address increment step size. The setting apply to source or destination address, depending on STEPSEL setting. Table 5-27. Members 5.6.5.2 Enum value Description DMA_ADDRESS_INCREMENT_STEP_SIZE_1 The address is incremented by (beat size * 1). DMA_ADDRESS_INCREMENT_STEP_SIZE_2 The address is incremented by (beat size * 2). DMA_ADDRESS_INCREMENT_STEP_SIZE_4 The address is incremented by (beat size * 4). DMA_ADDRESS_INCREMENT_STEP_SIZE_8 The address is incremented by (beat size * 8). DMA_ADDRESS_INCREMENT_STEP_SIZE_16 The address is incremented by (beat size * 16). DMA_ADDRESS_INCREMENT_STEP_SIZE_32 The address is incremented by (beat size * 32). DMA_ADDRESS_INCREMENT_STEP_SIZE_64 The address is incremented by (beat size * 64). DMA_ADDRESS_INCREMENT_STEP_SIZE_128 The address is incremented by (beat size * 128). Enum dma_beat_size AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 106 The basic transfer unit in DMAC is a beat, which is defined as a single bus access. Its size is configurable and applies to both read and write. Table 5-28. Members 5.6.5.3 Enum value Description DMA_BEAT_SIZE_BYTE 8-bit access. DMA_BEAT_SIZE_HWORD 16-bit access. DMA_BEAT_SIZE_WORD 32-bit access. Enum dma_block_action Block action definitions. Table 5-29. Members 5.6.5.4 Enum value Description DMA_BLOCK_ACTION_NOACT No action. DMA_BLOCK_ACTION_INT Channel in normal operation and sets transfer complete interrupt flag after block transfer. DMA_BLOCK_ACTION_SUSPEND Trigger channel suspend after block transfer and sets channel suspend interrupt flag once the channel is suspended. DMA_BLOCK_ACTION_BOTH Sets transfer complete interrupt flag after a block transfer and trigger channel suspend. The channel suspend interrupt flag will be set once the channel is suspended. Enum dma_callback_type Callback types for DMA callback driver. Table 5-30. Members 5.6.5.5 Enum value Description DMA_CALLBACK_TRANSFER_DONE Callback for transfer complete. DMA_CALLBACK_TRANSFER_ERROR Callback for any of transfer errors. A transfer error is flagged if a bus error is detected during an AHB access or when the DMAC fetches an invalid descriptor. DMA_CALLBACK_CHANNEL_SUSPEND Callback for channel suspend. DMA_CALLBACK_N Number of available callbacks. Enum dma_event_input_action DMA input actions. Table 5-31. Members Enum value Description DMA_EVENT_INPUT_NOACT No action. DMA_EVENT_INPUT_TRIG Normal transfer and periodic transfer trigger. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 107 5.6.5.6 Enum value Description DMA_EVENT_INPUT_CTRIG Conditional transfer trigger. DMA_EVENT_INPUT_CBLOCK Conditional block transfer. DMA_EVENT_INPUT_SUSPEND Channel suspend operation. DMA_EVENT_INPUT_RESUME Channel resume operation. DMA_EVENT_INPUT_SSKIP Skip next block suspend action. Enum dma_event_output_selection Event output selection. Table 5-32. Members 5.6.5.7 Enum value Description DMA_EVENT_OUTPUT_DISABLE Event generation disable. DMA_EVENT_OUTPUT_BLOCK Event strobe when block transfer complete. DMA_EVENT_OUTPUT_RESERVED Event output reserved. DMA_EVENT_OUTPUT_BEAT Event strobe when beat transfer complete. Enum dma_priority_level DMA priority level. Table 5-33. Members 5.6.5.8 Enum value Description DMA_PRIORITY_LEVEL_0 Priority level 0. DMA_PRIORITY_LEVEL_1 Priority level 1. DMA_PRIORITY_LEVEL_2 Priority level 2. DMA_PRIORITY_LEVEL_3 Priority level 3. Enum dma_step_selection DMA step selection. This bit determines whether the step size setting is applied to source or destination address. Table 5-34. Members 5.6.5.9 Enum value Description DMA_STEPSEL_DST Step size settings apply to the destination address. DMA_STEPSEL_SRC Step size settings apply to the source address. Enum dma_transfer_trigger_action DMA trigger action type. Table 5-35. Members Enum value Description DMA_TRIGGER_ACTON_BLOCK Perform a block transfer when triggered. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 108 Enum value Description DMA_TRIGGER_ACTON_BEAT Perform a beat transfer when triggered. DMA_TRIGGER_ACTON_TRANSACTION Perform a transaction when triggered. 5.7 Extra Information for DMAC Driver 5.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 5.7.2 Acronym Description DMA Direct Memory Access DMAC Direct Memory Access Controller CPU Central Processing Unit Dependencies This driver has the following dependencies: ● 5.7.3 System Clock Driver Errata There are no errata related to this driver. 5.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add SAM L21 support Initial Release 5.8 Examples for DMAC Driver This is a list of the available Quick Start Guides (QSGs) and example applications for SAM Direct Memory Access Controller Driver (DMAC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● Note 5.8.1 Quick Start Guide for Memory to Memory Data Transfer Using DMAC More DMA usage examples are available in peripheral QSGs. A quick start guide for TC/TCC 2 shows the usage of DMA event trigger; SERCOM SPI/USART/I C has example for DMA transfer from peripheral to memory or from memory to peripheral; ADC/DAC shows peripheral to peripheral transfer. Quick Start Guide for Memory to Memory Data Transfer Using DMAC The supported board list: ● SAMD21 Xplained Pro AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 109 ● SAMR21 Xplained Pro ● SAMD11 Xplained Pro ● SAML21 Xplained Pro In this use case, the DMAC is configured for: 5.8.1.1 ● Moving data from memory to memory ● Using software trigger ● Using DMA priority level 0 ● Transaction as DMA trigger action ● No action on input events ● Output event not enabled Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: #define DATA_LENGTH (512) static uint8_t source_memory[DATA_LENGTH]; static uint8_t destination_memory[DATA_LENGTH]; static volatile bool transfer_is_done = false; COMPILER_ALIGNED(16) DmacDescriptor example_descriptor; static void transfer_done( const struct dma_resource* const resource ) { transfer_is_done = true; } static void configure_dma_resource(struct dma_resource *resource) { struct dma_resource_config config; dma_get_config_defaults(&config); } dma_allocate(resource, &config); static void setup_transfer_descriptor(DmacDescriptor *descriptor ) { struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.block_transfer_count = sizeof(source_memory); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 110 descriptor_config.source_address = (uint32_t)source_memory + sizeof(source_memory); descriptor_config.destination_address = (uint32_t)destination_memory + sizeof(source_memory); } dma_descriptor_create(descriptor, &descriptor_config); Add the below section to user application initialization (typically the start of main()): configure_dma_resource(&example_resource); setup_transfer_descriptor(&example_descriptor); dma_add_descriptor(&example_resource, &example_descriptor); dma_register_callback(&example_resource, transfer_done, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&example_resource, DMA_CALLBACK_TRANSFER_DONE); for (uint32_t i = 0; i < DATA_LENGTH; i++) { source_memory[i] = i; } Workflow 1. Create a DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config config; 2. Initialize the DMA resource configuration struct with the module's default values. dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Allocate a DMA resource with the configurations. dma_allocate(resource, &config); 4. Declare a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; 5. Initialize the DMA transfer descriptor configuration struct with the module's default values. dma_descriptor_get_config_defaults(&descriptor_config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 111 Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 6. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. In this example, we have enabled the source and destination address increment. The source and destination addresses to be stored into descriptor_config must correspond to the end of the transfer. descriptor_config.block_transfer_count = sizeof(source_memory); descriptor_config.source_address = (uint32_t)source_memory + sizeof(source_memory); descriptor_config.destination_address = (uint32_t)destination_memory + sizeof(source_memory); 7. Create the DMA transfer descriptor. dma_descriptor_create(descriptor, &descriptor_config); 8. Add the DMA transfer descriptor to the allocated DMA resource. dma_add_descriptor(&example_resource, &example_descriptor); 9. Register a callback to indicate transfer status. dma_register_callback(&example_resource, transfer_done, DMA_CALLBACK_TRANSFER_DONE); 10. Set the transfer done flag in the registered callback function. static void transfer_done( const struct dma_resource* const resource ) { transfer_is_done = true; } 11. Enable the registered callbacks. dma_enable_callback(&example_resource, DMA_CALLBACK_TRANSFER_DONE); 5.8.1.2 Use Case Code Add the following code at the start of main(): struct dma_resource example_resource; Copy the following code to your user application: dma_start_transfer_job(&example_resource); dma_trigger_transfer(&example_resource); while (!transfer_is_done) { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 112 } /* Wait for transfer done */ while (true) { /* Nothing to do */ } Workflow 1. Start the DMA transfer job with the allocated DMA resource and transfer descriptor. dma_start_transfer_job(&example_resource); 2. Set the software trigger for the DMA channel. This can be done before or after the DMA job is started. Note that all transfers needs a trigger to start. dma_trigger_transfer(&example_resource); 3. Waiting for the setting of the transfer done flag. while (!transfer_is_done) { /* Wait for transfer done */ } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 113 6. SAM EEPROM Emulator Service (EEPROM) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an emulated EEPROM memory space in the device's FLASH memory, for the storage and retrieval of user-application configuration data into and out of non-volatile memory. The following peripherals are used by this module: ● NVM (Non-Volatile Memory Controller) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 6.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites The SAM device fuses must be configured via an external programmer or debugger, so that an EEPROM section is allocated in the main NVM flash memory contents. If a NVM section is not allocated for the EEPROM emulator, or if insufficient space for the emulator is reserved, the module will fail to initialize. 6.2 Module Overview As the SAM devices do not contain any physical EEPROM memory, the storage of non-volatile user data is instead emulated using a special section of the device's main FLASH memory. The use of FLASH memory technology over EEPROM presents several difficulties over true EEPROM memory; data must be written as a number of physical memory pages (of several bytes each) rather than being individually byte addressable, and entire rows of FLASH must be erased before new data may be stored. To help abstract these characteristics away from the user application an emulation scheme is implemented to present a more user-friendly API for data storage and retrieval. This module provides an EEPROM emulation layer on top of the device's internal NVM controller, to provide a standard interface for the reading and writing of non-volatile configuration data. This data is placed into the EEPROM emulated section of the device's main FLASH memory storage section, the size of which is configured using the device's fuses. Emulated EEPROM is exempt from the usual device NVM region lock bits, so that it may be read from or written to at any point in the user application. There are many different algorithms that may be employed for EEPROM emulation using FLASH memory, to tune the write and read latencies, RAM usage, wear levelling and other characteristics. As a result, multiple different emulator schemes may be implemented, so that the most appropriate scheme for a specific application's requirements may be used. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 114 6.2.1 Implementation Details The following information is relevant for EEPROM Emulator scheme 1, version 1.0.0, as implemented by this module. Other revisions or emulation schemes may vary in their implementation details and may have different wear-leveling, latency, and other characteristics. 6.2.1.1 Emulator Characteristics This emulator is designed for best reliability, with a good balance of available storage and write-cycle limits. It is designed to ensure that page data is automatically updated so that in the event of a failed update the previous data is not lost (when used correctly). With the exception of a system reset with data cached to the internal writecache buffer, at most only the latest write to physical non-volatile memory will be lost in the event of a failed write. This emulator scheme is tuned to give best write-cycle longevity when writes are confined to the same logical EEPROM page (where possible) and when writes across multiple logical EEPROM pages are made in a linear fashion through the entire emulated EEPROM space. 6.2.1.2 Physical Memory The SAM non-volatile FLASH is divided into a number of physical rows, each containing four identically sized flash pages. Pages may be read or written to individually, however pages must be erased before being reprogrammed and the smallest granularity available for erasure is one single row. This discrepancy results in the need for an emulator scheme that is able to handle the versioning and moving of page data to different physical rows as needed, erasing old rows ready for re-use by future page write operations. Physically, the emulated EEPROM segment is located at the end of the physical FLASH memory space, as shown in Figure 6-1: Physical Memory on page 115. Figure 6-1. Physical Memory E n d o f N VM M e m o r y Re s e r ve d E E P ROM S e c t io n S t a r t o f E E P ROM M e m o r y E n d o f Ap p lic a t io n M e m o r y Ap p lic a t io n S e c t io n S t a r t o f Ap p lic a t io n M e m o r y E n d o f Bo o t lo a d e r M e m o r y BOOT S e c t io n S t a r t o f N VM M e m o r y AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 115 6.2.1.3 Master Row One physical FLASH row at the end of the emulated EEPROM memory space is reserved for use by the emulator to store configuration data. The master row is not user-accessible, and is reserved solely for internal use by the emulator. 6.2.1.4 Spare Row As data needs to be preserved between row erasures, a single FLASH row is kept unused to act as destination for copied data when a write request is made to an already full row. When the write request is made, any logical pages of data in the full row that need to be preserved are written to the spare row along with the new (updated) logical page data, before the old row is erased and marked as the new spare. 6.2.1.5 Row Contents Each physical FLASH row initially stores the contents of two logical EEPROM memory pages. This halves the available storage space for the emulated EEPROM but reduces the overall number of row erases that are required, by reserving two pages within each row for updated versions of the logical page contents. See Figure 6-3: Initial Physical Layout of The Emulated EEPROM Memory on page 117 for a visual layout of the EEPROM Emulator physical memory. As logical pages within a physical row are updated, the new data is filled into the remaining unused pages in the row. Once the entire row is full, a new write request will copy the logical page not being written to in the current row to the spare row with the new (updated) logical page data, before the old row is erased. This system allows for the same logical page to be updated up to three times into physical memory before a row erasure procedure is needed. In the case of multiple versions of the same logical EEPROM page being stored in the same physical row, the right-most (highest physical FLASH memory page address) version is considered to be the most current. 6.2.1.6 Write Cache As a typical EEPROM use case is to write to multiple sections of the same EEPROM page sequentially, the emulator is optimized with a single logical EEPROM page write cache to buffer writes before they are written to the physical backing memory store. The cache is automatically committed when a new write request to a different logical EEPROM memory page is requested, or when the user manually commits the write cache. Without the write cache, each write request to an EEPROM memory page would require a full page write, reducing the system performance and significantly reducing the lifespan of the non-volatile memory. 6.2.2 Memory Layout A single logical EEPROM page is physically stored as the page contents and a header inside a single physical FLASH page, as shown in Figure 6-2: Internal Layout of An Emulated EEPROM Page on page 116. Figure 6-2. Internal Layout of An Emulated EEPROM Page NVMCTRL_PAGE_SIZE Bytes (64) Header User Page Data 4 Bytes 60 Bytes Within the EEPROM memory reservation section at the top of the NVM memory space, this emulator will produce the layout as shown in Figure 6-3: Initial Physical Layout of The Emulated EEPROM Memory on page 117 when initialized for the first time. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 116 Figure 6-3. Initial Physical Layout of The Emulated EEPROM Memory MASTER ROW MASTER ROW Logical Page 0 Revision 0 Logical Page 1 Revision 0 Logical Page 2 Revision 0 Logical Page 3 Revision 0 Logical Page 4 Revision 0 Logical Page 5 Revision 0 Logical Page 6 Revision 0 Logical Page 7 Revision 0 SPARE ROW SPARE ROW MASTER ROW MASTER ROW SPARE ROW SPARE ROW End of Flash End of FLASH – EEPROM Rows When an EEPROM page needs to be committed to physical memory, the next free FLASH page in the same row will be chosen - this makes recovery simple, as the right-most version of a logical page in a row is considered the most current. With four pages to a physical NVM row, this allows for up to three updates to the same logical page to be made before an erase is needed. Figure 6-4: First Write to Logical EEPROM Page N-1 on page 117 shows the result of the user writing an updated version of logical EEPROM page N-1 to the physical memory. Figure 6-4. First Write to Logical EEPROM Page N-1 MASTER ROW MASTER ROW MASTER ROW Logical Page 0 Revision 0 Logical Page 1 Revision 0 Logical Page 0 Revision 1 Logical Page 2 Revision 0 Logical Page 3 Revision 0 Logical Page 4 Revision 0 Logical Page 5 Revision 0 Logical Page 6 Revision 0 Logical Page 7 Revision 0 SPARE ROW SPARE ROW SPARE ROW MASTER ROW SPARE ROW End of Flash End of FLASH – EEPROM Rows A second write of the same logical EEPROM page results in the layout shown in Figure 6-5: Second Write to Logical EEPROM Page N-1 on page 117. Figure 6-5. Second Write to Logical EEPROM Page N-1 MASTER ROW MASTER ROW MASTER ROW MASTER ROW Logical Page 0 Revision 0 Logical Page 1 Revision 0 Logical Page 0 Revision 1 Logical Page 0 Revision 2 Logical Page 2 Revision 0 Logical Page 3 Revision 0 Logical Page 4 Revision 0 Logical Page 5 Revision 0 Logical Page 6 Revision 0 Logical Page 7 Revision 0 SPARE ROW SPARE ROW SPARE ROW SPARE ROW End of Flash End of FLASH – EEPROM Rows A third write of the same logical page requires that the EEPROM emulator erase the row, as it has become full. Prior to this, the contents of the unmodified page in the same row as the page being updated will be copied into the spare row, along with the new version of the page being updated. The old (full) row is then erased, resulting in the layout shown in Figure 6-6: Third Write to Logical EEPROM Page N-1 on page 118. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 117 Figure 6-6. Third Write to Logical EEPROM Page N-1 MASTER ROW MASTER ROW MASTER ROW MASTER ROW SPARE ROW SPARE ROW SPARE ROW SPARE ROW Logical Page 2 Revision 0 Logical Page 3 Revision 0 Logical Page 4 Revision 0 Logical Page 5 Revision 0 Logical Page 6 Revision 0 Logical Page 7 Revision 0 Logical Page 0 Revision 3 Logical Page 1 Revision 0 6.3 Special Considerations 6.3.1 NVM Controller Configuration End of Flash End of FLASH – EEPROM Rows The EEPROM Emulator service will initialize the NVM controller as part of its own initialization routine; the NVM controller will be placed in Manual Write mode, so that explicit write commands must be sent to the controller to commit a buffered page to physical memory. The manual write command must thus be issued to the NVM controller whenever the user application wishes to write to a NVM page for its own purposes. 6.3.2 Logical EEPROM Page Size As a small amount of information needs to be stored in a header before the contents of a logical EEPROM page in memory (for use by the emulation service), the available data in each EEPROM page is less than the total size of a single NVM memory page by several bytes. 6.3.3 Committing of the Write Cache A single-page write cache is used internally to buffer data written to pages in order to reduce the number of physical writes required to store the user data, and to preserve the physical memory lifespan. As a result, it is important that the write cache is committed to physical memory as soon as possible after a BOD low power condition, to ensure that enough power is available to guarantee a completed write so that no data is lost. The write cache must also be manually committed to physical memory if the user application is to perform any NVM operations using the NVM controller directly. 6.4 Extra Information For extra information, see Extra Information. This includes: 6.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for Emulated EEPROM Service. 6.6 API Overview 6.6.1 Structure Definitions 6.6.1.1 Struct eeprom_emulator_parameters AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 118 Structure containing the memory layout parameters of the EEPROM emulator module. Table 6-1. Members Type Name Description uint16_t eeprom_number_of_pages Number of emulated pages of EEPROM. uint8_t page_size Number of bytes per emulated EEPROM page. 6.6.2 Macro Definitions 6.6.2.1 EEPROM Emulator Information Macro EEPROM_EMULATOR_ID #define EEPROM_EMULATOR_ID 1 Emulator scheme ID, identifying the scheme used to emulated EEPROM storage. Macro EEPROM_MAJOR_VERSION #define EEPROM_MAJOR_VERSION 1 Emulator major version number, identifying the emulator major version. Macro EEPROM_MINOR_VERSION #define EEPROM_MINOR_VERSION 0 Emulator minor version number, identifying the emulator minor version. Macro EEPROM_REVISION #define EEPROM_REVISION 0 Emulator revision version number, identifying the emulator revision. Macro EEPROM_PAGE_SIZE #define EEPROM_PAGE_SIZE (NVMCTRL_PAGE_SIZE - EEPROM_HEADER_SIZE) Size of the user data portion of each logical EEPROM page, in bytes. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 119 6.6.3 Function Definitions 6.6.3.1 Configuration and Initialization Function eeprom_emulator_init() Initializes the EEPROM Emulator service. enum status_code eeprom_emulator_init(void) Initializes the emulated EEPROM memory space; if the emulated EEPROM memory has not been previously initialized, it will need to be explicitly formatted via eeprom_emulator_erase_memory(). The EEPROM memory space will not be automatically erased by the initialization function, so that partial data may be recovered by the user application manually if the service is unable to initialize successfully. Returns Status code indicating the status of the operation. Table 6-2. Return Values Return value Description STATUS_OK EEPROM emulation service was successfully initialized STATUS_ERR_NO_MEMORY No EEPROM section has been allocated in the device STATUS_ERR_BAD_FORMAT Emulated EEPROM memory is corrupt or not formatted STATUS_ERR_IO EEPROM data is incompatible with this version or scheme of the EEPROM emulator Function eeprom_emulator_erase_memory() Erases the entire emulated EEPROM memory space. void eeprom_emulator_erase_memory(void) Erases and re-initializes the emulated EEPROM memory space, destroying any existing data. Function eeprom_emulator_get_parameters() Retrieves the parameters of the EEPROM Emulator memory layout. enum status_code eeprom_emulator_get_parameters( struct eeprom_emulator_parameters *const parameters) Retrieves the configuration parameters of the EEPROM Emulator, after it has been initialized. Table 6-3. Parameters Data direction Parameter name Description [out] parameters EEPROM Emulator parameter struct to fill AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 120 Returns Status of the operation. Table 6-4. Return Values 6.6.3.2 Return value Description STATUS_OK If the emulator parameters were retrieved successfully STATUS_ERR_NOT_INITIALIZED If the EEPROM Emulator is not initialized Logical EEPROM Page Reading/Writing Function eeprom_emulator_commit_page_buffer() Commits any cached data to physical non-volatile memory. enum status_code eeprom_emulator_commit_page_buffer(void) Commits the internal SRAM caches to physical non-volatile memory, to ensure that any outstanding cached data is preserved. This function should be called prior to a system reset or shutdown to prevent data loss. Note This should be the first function executed in a BOD33 Early Warning callback to ensure that any outstanding cache data is fully written to prevent data loss. This function should also be called before using the NVM controller directly in the user-application for any other purposes to prevent data loss. Returns Status code indicating the status of the operation. Function eeprom_emulator_write_page() Writes a page of data to an emulated EEPROM memory page. enum status_code eeprom_emulator_write_page( const uint8_t logical_page, const uint8_t *const data) Writes an emulated EEPROM page of data to the emulated EEPROM memory space. Note Data stored in pages may be cached in volatile RAM memory; to commit any cached data to physical non-volatile memory, the eeprom_emulator_commit_page_buffer() function should be called. Table 6-5. Parameters Data direction Parameter name Description [in] logical_page Logical EEPROM page number to write to [in] data Pointer to the data buffer containing source data to write AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 121 Returns Status code indicating the status of the operation. Table 6-6. Return Values Return value Description STATUS_OK If the page was successfully read STATUS_ERR_NOT_INITIALIZED If the EEPROM emulator is not initialized STATUS_ERR_BAD_ADDRESS If an address outside the valid emulated EEPROM memory space was supplied Function eeprom_emulator_read_page() Reads a page of data from an emulated EEPROM memory page. enum status_code eeprom_emulator_read_page( const uint8_t logical_page, uint8_t *const data) Reads an emulated EEPROM page of data from the emulated EEPROM memory space. Table 6-7. Parameters Returns Data direction Parameter name Description [in] logical_page Logical EEPROM page number to read from [out] data Pointer to the destination data buffer to fill Status code indicating the status of the operation. Table 6-8. Return Values 6.6.3.3 Return value Description STATUS_OK If the page was successfully read STATUS_ERR_NOT_INITIALIZED If the EEPROM emulator is not initialized STATUS_ERR_BAD_ADDRESS If an address outside the valid emulated EEPROM memory space was supplied Buffer EEPROM Reading/Writing Function eeprom_emulator_write_buffer() Writes a buffer of data to the emulated EEPROM memory space. enum status_code eeprom_emulator_write_buffer( const uint16_t offset, const uint8_t *const data, const uint16_t length) Writes a buffer of data to a section of emulated EEPROM memory space. The source buffer may be of any size, and the destination may lie outside of an emulated EEPROM page boundary. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 122 Note Data stored in pages may be cached in volatile RAM memory; to commit any cached data to physical non-volatile memory, the eeprom_emulator_commit_page_buffer() function should be called. Table 6-9. Parameters Data direction Parameter name Description [in] offset Starting byte offset to write to, in emulated EEPROM memory space [in] data Pointer to the data buffer containing source data to write [in] length Length of the data to write, in bytes Returns Status code indicating the status of the operation. Table 6-10. Return Values Return value Description STATUS_OK If the page was successfully read STATUS_ERR_NOT_INITIALIZED If the EEPROM emulator is not initialized STATUS_ERR_BAD_ADDRESS If an address outside the valid emulated EEPROM memory space was supplied Function eeprom_emulator_read_buffer() Reads a buffer of data from the emulated EEPROM memory space. enum status_code const uint16_t uint8_t *const const uint16_t eeprom_emulator_read_buffer( offset, data, length) Reads a buffer of data from a section of emulated EEPROM memory space. The destination buffer may be of any size, and the source may lie outside of an emulated EEPROM page boundary. Table 6-11. Parameters Returns Data direction Parameter name Description [in] offset Starting byte offset to read from, in emulated EEPROM memory space [out] data Pointer to the data buffer containing source data to read [in] length Length of the data to read, in bytes Status code indicating the status of the operation. Table 6-12. Return Values Return value Description STATUS_OK If the page was successfully read AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 123 Return value Description STATUS_ERR_NOT_INITIALIZED If the EEPROM emulator is not initialized STATUS_ERR_BAD_ADDRESS If an address outside the valid emulated EEPROM memory space was supplied 6.7 Extra Information 6.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 6.7.2 Acronym Description EEPROM Electronically Erasable Read-Only Memory NVM Non-Volatile Memory Dependencies This driver has the following dependencies: ● 6.7.3 Non-Volatile Memory Controller Driver Errata There are no errata related to this driver. 6.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add support for SAM L21 Fix warnings and document for SAM D21 Initial Release 6.8 Examples for Emulated EEPROM Service This is a list of the available Quick Start guides (QSGs) and example applications for SAM EEPROM Emulator Service (EEPROM). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● 6.8.1 Quick Start Guide for the Emulated EEPROM Module - Basic Use Case Quick Start Guide for the Emulated EEPROM Module - Basic Use Case In this use case, the EEPROM emulator module is configured and a sample page of data read and written. The first byte of the first EEPROM page is toggled, and a LED is turned on or off to reflect the new state. Each time the device is reset, the LED should toggle to a different state to indicate correct non-volatile storage and retrieval. 6.8.1.1 Prerequisites The device's fuses must be configured to reserve a sufficient number of FLASH memory rows for use by the EEPROM emulator service, before the service can be used. That is: NVMCTRL_FUSES_EEPROM_SIZE has to be set to less than 0x5 in the fuse setting, then there will be more than 8 pages size for EEPROM. Atmel Studio can be used to set this fuse(Tools->Device Programming). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 124 6.8.1.2 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_eeprom(void) { /* Setup EEPROM emulator service */ enum status_code error_code = eeprom_emulator_init(); } if (error_code == STATUS_ERR_NO_MEMORY) { while (true) { /* No EEPROM section has been set in the device's fuses */ } } else if (error_code != STATUS_OK) { /* Erase the emulated EEPROM memory (assume it is unformatted or * irrecoverably corrupt) */ eeprom_emulator_erase_memory(); eeprom_emulator_init(); } Add to user application initialization (typically the start of main()): configure_eeprom(); Workflow 1. Attempt to initialize the EEPROM emulator service, storing the error code from the initialization function into a temporary variable. enum status_code error_code = eeprom_emulator_init(); 2. Check if the emulator failed to initialize due to the device fuses not being configured to reserve enough of the main FLASH memory rows for emulated EEPROM usage - abort if the fuses are mis-configured. if (error_code == STATUS_ERR_NO_MEMORY) { while (true) { /* No EEPROM section has been set in the device's fuses */ } } 3. Check if the emulator service failed to initialize for any other reason; if so assume the emulator physical memory is unformatted or corrupt and erase/re-try initialization. else if (error_code != STATUS_OK) { /* Erase the emulated EEPROM memory (assume it is unformatted or * irrecoverably corrupt) */ eeprom_emulator_erase_memory(); eeprom_emulator_init(); } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 125 6.8.1.3 Use Case Code Copy-paste the following code to your user application: uint8_t page_data[EEPROM_PAGE_SIZE]; eeprom_emulator_read_page(0, page_data); page_data[0] = !page_data[0]; port_pin_set_output_level(LED_0_PIN, page_data[0]); eeprom_emulator_write_page(0, page_data); eeprom_emulator_commit_page_buffer(); while (true) { } Workflow 1. Create a buffer to hold a single emulated EEPROM page of memory, and read out logical EEPROM page zero into it. uint8_t page_data[EEPROM_PAGE_SIZE]; eeprom_emulator_read_page(0, page_data); 2. Toggle the first byte of the read page. page_data[0] = !page_data[0]; 3. Output the toggled LED state onto the board LED. port_pin_set_output_level(LED_0_PIN, page_data[0]); 4. Write the modified page back to logical EEPROM page zero, flushing the internal emulator write cache afterwards to ensure it is immediately written to physical non-volatile memory. eeprom_emulator_write_page(0, page_data); eeprom_emulator_commit_page_buffer(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 126 7. SAM Event System Driver (EVENTS) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's peripheral event resources and users within the device, including enabling and disabling of peripheral source selection and synchronization of clock domains between various modules. The following API modes is covered by this manual: ● Polled API ● Interrupt hook API The following peripherals are used by this module: ● EVSYS (Event System Management) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 7.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 7.2 Module Overview Peripherals within the SAM devices are capable of generating two types of actions in response to given stimulus; set a register flag for later intervention by the CPU (using interrupt or polling methods), or generate event signals which can be internally routed directly to other peripherals within the device. The use of events allows for direct actions to be performed in one peripheral in response to a stimulus in another without CPU intervention. This can lower the overall power consumption of the system if the CPU is able to remain in sleep modes for longer periods (SleepWalking), and lowers the latency of the system response. The event system is comprised of a number of freely configurable Event resources, plus a number of fixed Event Users. Each Event resource can be configured to select the input peripheral that will generate the events signal, as well as the synchronization path and edge detection mode. The fixed-function Event Users, connected to peripherals within the device, can then subscribe to an Event resource in a one-to-many relationship in order to 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 127 receive events as they are generated. An overview of the event system chain is shown in Figure 7-1: Module Overview on page 128. Figure 7-1. Module Overview E ve n t User X Sou r ce P e r ip h e r a l (Ge n e r a t o r ) De s t in a t io n P e r ip h e r a l (U s e r ) E ve n t Re s o u r c e A E ve n t User Y De s t in a t io n P e r ip h e r a l (U s e r ) There are many different events that can be routed in the device, which can then trigger many different actions. For example, an Analog Comparator module could be configured to generate an event when the input signal rises above the compare threshold, which then triggers a Timer Counter module to capture the current count value for later use. 7.2.1 Event Channels The Event module in each device consists of several channels, which can be freely linked to an event generator (i.e. a peripheral within the device that is capable of generating events). Each channel can be individually configured to select the generator peripheral, signal path and edge detection applied to the input event signal, before being passed to any event user(s). Event channels can support multiple users within the device in a standardized manner; when an Event User is linked to an Event Channel, the channel will automatically handshake with all attached users to ensure that all modules correctly receive and acknowledge the event. 7.2.2 Event Users Event Users are able to subscribe to an Event Channel, once it has been configured. Each Event User consists of a fixed connection to one of the peripherals within the device (for example, an ADC module, or Timer module) and is capable of being connected to a single Event Channel. 7.2.3 Edge Detection For asynchronous events, edge detection on the event input is not possible, and the event signal must be passed directly between the event generator and event user. For synchronous and re-synchronous events, the input signal from the event generator must pass through an edge detection unit, so that only the rising, falling, or both edges of the event signal triggers an action in the event user. 7.2.4 Path Selection The event system in the SAM devices supports three signal path types from the event generator to event users: asynchronous, synchronous, and re-synchronous events. 7.2.4.1 Asynchronous Paths Asynchronous event paths allow for an asynchronous connection between the event generator and event user(s), when the source and destination peripherals share the same Generic Clock channel. In this mode the event is propagated between the source and destination directly to reduce the event latency, thus no edge detection is possible. The asynchronous event chain is shown in Figure 7-2: Asynchronous Paths on page 129. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 128 Figure 7-2. Asynchronous Paths Sou r ce P e r ip h e r a l Note 7.2.4.2 E VS YS E ve n t Ch a n n e l/U s e r De s t in a t io n P e r ip h e r a l Identically shaped borders in the diagram indicate a shared generic clock channel. Synchronous Paths The Synchronous event path should be used when edge detection or interrupts from the event channel are required, and the source event generator and the event channel shares the same Generic Clock channel. The synchronous event chain is shown in Figure 7-3: Synchronous Paths on page 129. Not all peripherals support Synchronous event paths; refer to the device datasheet. Figure 7-3. Synchronous Paths Sou r ce P e r ip h e r a l Note 7.2.4.3 E VS YS E ve n t Ch a n n e l/U s e r De s t in a t io n P e r ip h e r a l Identically shaped borders in the diagram indicate a shared generic clock channel. Re-synchronous Paths Re-synchronous event paths are a special form of synchronous events, where when edge detection or interrupts from the event channel are required, but the event generator and the event channel use different Generic Clock channels. The re-synchronous path allows the Event System to synchronize the incoming event signal from the Event Generator to the clock of the Event System module to avoid missed events, at the cost of a higher latency due to the re-synchronization process. The re-synchronous event chain is shown in Figure 7-4: Re-synchronous Paths on page 129. Not all peripherals support re-synchronous event paths; refer to the device datasheet. Figure 7-4. Re-synchronous Paths Sou r ce P e r ip h e r a l Note 7.2.5 E VS YS E ve n t Ch a n n e l/U s e r De s t in a t io n P e r ip h e r a l Identically shaped borders in the diagram indicate a shared generic clock channel. Physical Connection Figure 7-5: Physical Connection on page 130 shows how this module is interconnected within the device. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 129 Figure 7-5. Physical Connection Sou r ce P e r ip h e r a ls 7.2.6 E VS YS E VS YS Sou r ce Ch a n n e l M U Xs E ve n t Ch a n n e ls M U Xs E ve n t U s e r s De s t in a t io n P e r ip h e r a ls Configuring Events For SAM devices, several steps are required to properly configure an event chain, so that hardware peripherals can respond to events generated by each other, listed below. 7.2.6.1 7.2.6.2 7.2.6.3 7.3 Source Peripheral 1. The source peripheral (that will generate events) must be configured and enabled. 2. The source peripheral (that will generate events) must have an output event enabled. Event System 1. An event system channel must be allocated and configured with the correct source peripheral selected as the channel's event generator. 2. The event system user must be configured and enabled, and attached to # event channel previously allocated. Destination Peripheral 1. The destination peripheral (that will receive events) must be configured and enabled. 2. The destination peripheral (that will receive events) must have an input event enabled. Special Considerations There are no special considerations for this module. 7.4 Extra Information For extra information, see Extra Information for EVENTS Driver. This includes: 7.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for EVENTS Driver. 7.6 API Overview 7.6.1 Variable and Type Definitions 7.6.1.1 Type events_interrupt_hook typedef void(* events_interrupt_hook )(struct events_resource *resource) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 130 7.6.2 Structure Definitions 7.6.2.1 Struct events_config This events configuration struct is used to configure each of the channels. Table 7-1. Members 7.6.2.2 Type Name Description uint8_t clock_source Clock source for the event channel. enum events_edge_detect edge_detect Select edge detection mode. uint8_t generator Set event generator for the channel. enum events_path_selection path Select events channel path. Type Name Description events_interrupt_hook hook_func struct events_hook * next struct events_resource * resource Struct events_hook Table 7-2. Members 7.6.2.3 Struct events_resource Event resource structure. Note The fields in this structure should not be altered by the user application; they are reserved for driver internals only. 7.6.3 Macro Definitions 7.6.3.1 Macro EVSYS_ID_GEN_NONE #define EVSYS_ID_GEN_NONE 0 Use this to disable any peripheral event input to a channel. This can be useful if you only want to use a channel for software generated events. Definition for no generator selection. 7.6.4 Function Definitions 7.6.4.1 Function events_ack_interrupt() Acknowledge an interrupt source. enum status_code events_ack_interrupt( struct events_resource * resource, enum events_interrupt_source source) Acknowledge an interrupt source so the interrupt state is cleared in hardware. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 131 Table 7-3. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] source One of the members in the events_interrupt_source enumerator Returns Status of the interrupt source. Table 7-4. Return Values 7.6.4.2 Return value Description STATUS_OK Interrupt source was acknowledged successfully Function events_add_hook() Insert hook into the event drivers interrupt hook queue. enum status_code events_add_hook( struct events_resource * resource, struct events_hook * hook) Inserts a hook into the event drivers interrupt hook queue. Table 7-5. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] hook Pointer to an events_hook struct instance Status of the insertion procedure. Table 7-6. Return Values 7.6.4.3 Return value Description STATUS_OK Insertion of hook went successful Function events_allocate() Allocate an event channel and set configuration. enum status_code events_allocate( struct events_resource * resource, struct events_config * config) Allocates an event channel from the event channel pool and sets the channel configuration. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 132 Table 7-7. Parameters Data direction Parameter name Description [out] resource Pointer to a events_resource struct instance [in] config Pointer to a events_config struct Returns Status of the configuration procedure. Table 7-8. Return Values 7.6.4.4 Return value Description STATUS_OK Allocation and configuration went successful STATUS_ERR_NOT_FOUND No free event channel found Function events_attach_user() Attach user to the event channel. enum status_code events_attach_user( struct events_resource * resource, uint8_t user_id) Attach a user peripheral to the event channel to receive events. Table 7-9. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] user_id A number identifying the user peripheral found in the device header file. Status of the user attach procedure. Table 7-10. Return Values 7.6.4.5 Return value Description STATUS_OK No errors detected when attaching the event user Function events_create_hook() Initializes a interrupt hook for insertion in the event interrupt hook queue. enum status_code events_create_hook( struct events_hook * hook, events_interrupt_hook hook_func) Initializes a hook structure so it is ready for insertion in the interrupt hook queue. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 133 Table 7-11. Parameters Data direction Parameter name Description [out] hook Pointer to an events_hook struct instance [in] hook_func Pointer to a function containing the interrupt hook code Returns Status of the hook creation procedure. Table 7-12. Return Values 7.6.4.6 Return value Description STATUS_OK Creation and initialization of interrupt hook went successful Function events_del_hook() Remove hook from the event drivers interrupt hook queue. enum status_code events_del_hook( struct events_resource * resource, struct events_hook * hook) Removes a hook from the event drivers interrupt hook queue. Table 7-13. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] hook Pointer to an events_hook struct instance Status of the removal procedure. Table 7-14. Return Values 7.6.4.7 Return value Description STATUS_OK Removal of hook went successful STATUS_ERR_NO_MEMORY There is no hooks instances in the event driver interrupt hook list STATUS_ERR_NOT_FOUND Interrupt hook not found in the event drivers interrupt hook list Function events_detach_user() Detach an user peripheral from the event channel. enum status_code events_detach_user( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 134 struct events_resource * resource, uint8_t user_id) Deattach an user peripheral from the event channels so it does not receive any more events. Table 7-15. Parameters Data direction Parameter name Description [in] resource Pointer to an event_resource struct instance [in] user_id A number identifying the user peripheral found in the device header file. Returns Status of the user detach procedure. Table 7-16. Return Values 7.6.4.8 Return value Description STATUS_OK No errors detected when detaching the event user Function events_disable_interrupt_source() Disable interrupt source. enum status_code events_disable_interrupt_source( struct events_resource * resource, enum events_interrupt_source source) Disable an interrupt source so can trigger execution of an interrupt hook. Table 7-17. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] source One of the members in the events_interrupt_source enumerator Status of the interrupt source enable procedure. Table 7-18. Return Values 7.6.4.9 Return value Description STATUS_OK Enabling of the interrupt source went successful STATUS_ERR_INVALID_ARG Interrupt source does not exist Function events_enable_interrupt_source() Enable interrupt source. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 135 enum status_code events_enable_interrupt_source( struct events_resource * resource, enum events_interrupt_source source) Enable an interrupt source so can trigger execution of an interrupt hook. Table 7-19. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] source One of the members in the events_interrupt_source enumerator Returns Status of the interrupt source enable procedure. Table 7-20. Return Values Return value Description STATUS_OK Enabling of the interrupt source went successful STATUS_ERR_INVALID_ARG Interrupt source does not exist 7.6.4.10 Function events_get_config_defaults() Initializes an event configurations struct to defaults. void events_get_config_defaults( struct events_config * config) Initailizes an event configuration struct to predefined safe default settings. Table 7-21. Parameters Data direction Parameter name Description [in] config Pointer to an instance of struct events_config 7.6.4.11 Function events_get_free_channels() Get number of free channels. uint8_t events_get_free_channels(void) Get number of allocatable channels in the events system resource pool. Returns The number of free channels in the event system. 7.6.4.12 Function events_is_busy() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 136 Check if a channel is busy. bool events_is_busy( struct events_resource * resource) Check if a channel is busy, a channels stays busy until all users connected to the channel has handled an event. Table 7-22. Parameters Data direction Parameter name Description [in] resource Pointer to a events_resource struct instance Returns Status of the channels busy state. Table 7-23. Return Values Return value Description true One or more users connected to the channel has not handled the last event false All users are ready handle new events 7.6.4.13 Function events_is_detected() Check if event is detected on event channel. bool events_is_detected( struct events_resource * resource) Check if an event has been detected on the channel. Note This function will clear the event detected interrupt flag. Table 7-24. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct Returns Status of the event detection interrupt flag. Table 7-25. Return Values Return value Description true Event has been detected false Event has not been detected 7.6.4.14 Function events_is_interrupt_set() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 137 Check if interrupt source is set. bool events_is_interrupt_set( struct events_resource * resource, enum events_interrupt_source source) Check if an interrupt source is set and should be processed. Table 7-26. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct instance [in] source One of the members in the events_interrupt_source enumerator Returns Status of the interrupt source. Table 7-27. Return Values Return value Description true Interrupt source is set false Interrupt source is not set 7.6.4.15 Function events_is_overrun() Check if there has been an overrun situation on this channel. bool events_is_overrun( struct events_resource * resource) Check if there has been an overrun situation on this channel. Note This function will clear the event overrun detected interrupt flag. Table 7-28. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct Returns Status of the event overrun interrupt flag. Table 7-29. Return Values Return value Description true Event overrun has been detected false Event overrun has not been detected AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 138 7.6.4.16 Function events_is_users_ready() Check if all users connected to the channel is ready. bool events_is_users_ready( struct events_resource * resource) Check if all users connected to the channel is ready to handle incomming events. Table 7-30. Parameters Data direction Parameter name Description [in] resource Pointer to an events_resource struct Returns The ready status of users connected to an event channel. Table 7-31. Return Values Return value Description true All users connect to event channel is ready handle incomming events false One or more users connect to event channel is not ready to handle incomming events 7.6.4.17 Function events_release() Release allocated channel back the the resource pool. enum status_code events_release( struct events_resource * resource) Release an allocated channel back to the resource pool to make it available for other purposes. Table 7-32. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct Status of channel release procedure. Table 7-33. Return Values Return value Description STATUS_OK No error was detected when channel was released STATUS_BUSY One or more event users have not processed the last event STATUS_ERR_NOT_INITIALIZED Channel not allocated, and can derfor not be released 7.6.4.18 Function events_trigger() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 139 Trigger software event. enum status_code events_trigger( struct events_resource * resource) Trigger an event by software. Table 7-34. Parameters Returns Data direction Parameter name Description [in] resource Pointer to an events_resource struct Status of the event software procedure. Table 7-35. Return Values Return value Description STATUS_OK No error was detected when software tigger signal was issued STATUS_ERR_UNSUPPORTED_DEV If the channel path is asynchronous and/or the edge detection is not set to RISING 7.6.5 Enumeration Definitions 7.6.5.1 Enum events_edge_detect Event channel edge detect setting. Table 7-36. Members 7.6.5.2 Enum value Description EVENTS_EDGE_DETECT_NONE No event output. EVENTS_EDGE_DETECT_RISING Event on rising edge. EVENTS_EDGE_DETECT_FALLING Event on falling edge. EVENTS_EDGE_DETECT_BOTH Event on both edges. Enum events_interrupt_source Interrupt source selector definitions. Table 7-37. Members 7.6.5.3 Enum value Description EVENTS_INTERRUPT_OVERRUN Overrun in event channel detected interrupt. EVENTS_INTERRUPT_DETECT Event signal propagation in event channel detected interrupt. Enum events_path_selection Event channel path selection. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 140 Table 7-38. Members Enum value Description EVENTS_PATH_SYNCHRONOUS Select the synchronous path for this event channel. EVENTS_PATH_RESYNCHRONIZED Select the resynchronizer path for this event channel. EVENTS_PATH_ASYNCHRONOUS Select the asynchronous path for this event channel. 7.7 Extra Information for EVENTS Driver 7.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 7.7.2 Acronym Description CPU Central Processing Unit MUX Multiplexer Dependencies This driver has the following dependencies: ● 7.7.3 System Clock Driver Errata There are no errata related to this driver. 7.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Fix a bug in internal function _events_find_bit_position() Rewrite of events driver Initial Release 7.8 Examples for EVENTS Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Event System Driver (EVENTS). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_events_basic_use_case ● asfdoc_sam0_events_interrupt_hook_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 141 8. SAM External Interrupt Driver (EXTINT) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of external interrupts generated by the physical device pins, including edge detection. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● EIC (External Interrupt Controller) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 8.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 8.2 Module Overview The External Interrupt (EXTINT) module provides a method of asynchronously detecting rising edge, falling edge or specific level detection on individual I/O pins of a device. This detection can then be used to trigger a software interrupt or event, or polled for later use if required. External interrupts can also optionally be used to automatically wake up the device from sleep mode, allowing the device to conserve power while still being able to react to an external stimulus in a timely manner. 8.2.1 Logical Channels The External Interrupt module contains a number of logical channels, each of which is capable of being individually configured for a given pin routing, detection mode, and filtering/wake up characteristics. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 142 Each individual logical external interrupt channel may be routed to a single physical device I/O pin in order to detect a particular edge or level of the incoming signal. 8.2.2 NMI Channels One or more Non Maskable Interrupt (NMI) channels are provided within each physical External Interrupt Controller module, allowing a single physical pin of the device to fire a single NMI interrupt in response to a particular edge or level stimulus. A NMI cannot, as the name suggests, be disabled in firmware and will take precedence over any inprogress interrupt sources. NMIs can be used to implement critical device features such as forced software reset or other functionality where the action should be executed in preference to all other running code with a minimum amount of latency. 8.2.3 Input Filtering and Detection To reduce the possibility of noise or other transient signals causing unwanted device wake-ups, interrupts and/ or events via an external interrupt channel, a hardware signal filter can be enabled on individual channels. This filter provides a Majority-of-Three voter filter on the incoming signal, so that the input state is considered to be the majority vote of three subsequent samples of the pin input buffer. The possible sampled input and resulting filtered output when the filter is enabled is shown in Table 8-1: Sampled Input and Rresulting Filtered Output on page 143. Table 8-1. Sampled Input and Rresulting Filtered Output 8.2.4 Input Sample 1 Input Sample 2 Input Sample 3 Filtered Output 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 1 1 0 0 0 1 0 1 1 1 1 0 1 1 1 1 1 Events and Interrupts Channel detection states may be polled inside the application for synchronous detection, or events and interrupts may be used for asynchronous behavior. Each channel can be configured to give an asynchronous hardware event (which may in turn trigger actions in other hardware modules) or an asynchronous software interrupt. Note 8.2.5 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the input event of another. For more information on event routing, refer to the event driver documentation. Physical Connection Figure 8-1: Physical Connection on page 144 shows how this module is interconnected within the device. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 143 Figure 8-1. Physical Connection Por t Pa d P e r ip h e r a l M U X E IC M o d u le 8.3 Ot h e r P e r ip h e r a l M o d u le s Special Considerations Not all devices support disabling of the NMI channel(s) detection mode - see your device datasheet. 8.4 Extra Information For extra information, see Extra Information for EXTINT Driver. This includes: 8.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for EXTINT Driver. 8.6 API Overview 8.6.1 Variable and Type Definitions 8.6.1.1 Type extint_callback_t typedef void(* extint_callback_t )(void) Type definition for an EXTINT module callback function. 8.6.2 Structure Definitions 8.6.2.1 Struct extint_chan_conf Configuration structure for the edge detection mode of an external interrupt channel. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 144 Table 8-2. Members 8.6.2.2 Type Name Description enum extint_detect detection_criteria Edge detection mode to use. bool filter_input_signal Filter the raw input signal to prevent noise from triggering an interrupt accidentally, using a 3 sample majority filter. uint32_t gpio_pin GPIO pin the NMI should be connected to. uint32_t gpio_pin_mux MUX position the GPIO pin should be configured to. enum extint_pull gpio_pin_pull Internal pull to enable on the input pin. bool wake_if_sleeping Wake up the device if the channel interrupt fires during sleep mode. Struct extint_events Event flags for the extint_enable_events() and extint_disable_events(). Table 8-3. Members 8.6.2.3 Type Name Description bool generate_event_on_detect[] If true, an event will be generated when an external interrupt channel detection state changes. Struct extint_nmi_conf Configuration structure for the edge detection mode of an external interrupt NMI channel. Table 8-4. Members Type Name Description enum extint_detect detection_criteria Edge detection mode to use. Not all devices support all possible detection modes for NMIs. bool filter_input_signal Filter the raw input signal to prevent noise from triggering an interrupt accidentally, using a 3 sample majority filter. uint32_t gpio_pin GPIO pin the NMI should be connected to. uint32_t gpio_pin_mux MUX position the GPIO pin should be configured to. enum extint_pull gpio_pin_pull Internal pull to enable on the input pin. 8.6.3 Macro Definitions 8.6.3.1 Macro EIC_NUMBER_OF_INTERRUPTS AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 145 #define EIC_NUMBER_OF_INTERRUPTS 16 8.6.3.2 Macro EXTINT_CLK_GCLK #define EXTINT_CLK_GCLK 0 The EIC is clocked by GCLK_EIC. 8.6.3.3 Macro EXTINT_CLK_ULP32K #define EXTINT_CLK_ULP32K 1 The EIC is clocked by CLK_ULP32K. 8.6.4 Function Definitions 8.6.4.1 Event Management Function extint_enable_events() Enables an External Interrupt event output. void extint_enable_events( struct extint_events *const events) Enables one or more output events from the External Interrupt module. See here for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 8-5. Parameters Data direction Parameter name Description [in] events Struct containing flags of events to enable Function extint_disable_events() Disables an External Interrupt event output. void extint_disable_events( struct extint_events *const events) Disables one or more output events from the External Interrupt module. See here for a list of events this module supports. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 146 Note Events cannot be altered while the module is enabled. Table 8-6. Parameters 8.6.4.2 Data direction Parameter name Description [in] events Struct containing flags of events to disable Configuration and Initialization (Channel) Function extint_chan_get_config_defaults() Initializes an External Interrupt channel configuration structure to defaults. void extint_chan_get_config_defaults( struct extint_chan_conf *const config) Initializes a given External Interrupt channel configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Wake the device if an edge detection occurs whilst in sleep ● Input filtering disabled ● Internal pull-up enabled ● Detect falling edges of a signal Table 8-7. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function extint_chan_set_config() Writes an External Interrupt channel configuration to the hardware module. void extint_chan_set_config( const uint8_t channel, const struct extint_chan_conf *const config) Writes out a given configuration of an External Interrupt channel configuration to the hardware module. If the channel is already configured, the new configuration will replace the existing one. Table 8-8. Parameters Data direction Parameter name Description [in] channel External Interrupt channel to configure [in] config Configuration settings for the channel AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 147 8.6.4.3 Configuration and Initialization (NMI) Function extint_nmi_get_config_defaults() Initializes an External Interrupt NMI channel configuration structure to defaults. void extint_nmi_get_config_defaults( struct extint_nmi_conf *const config) Initializes a given External Interrupt NMI channel configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Input filtering disabled ● Detect falling edges of a signal ● Asynchronous edge detection is disabled Table 8-9. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function extint_nmi_set_config() Writes an External Interrupt NMI channel configuration to the hardware module. enum status_code extint_nmi_set_config( const uint8_t nmi_channel, const struct extint_nmi_conf *const config) Writes out a given configuration of an External Interrupt NMI channel configuration to the hardware module. If the channel is already configured, the new configuration will replace the existing one. Table 8-10. Parameters Returns Data direction Parameter name Description [in] nmi_channel External Interrupt NMI channel to configure [in] config Configuration settings for the channel Status code indicating the success or failure of the request. Table 8-11. Return Values Return value Description STATUS_OK Configuration succeeded AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 148 8.6.4.4 Return value Description STATUS_ERR_PIN_MUX_INVALID An invalid pinmux value was supplied STATUS_ERR_BAD_FORMAT An invalid detection mode was requested Detection testing and clearing (channel) Function extint_chan_is_detected() Retrieves the edge detection state of a configured channel. bool extint_chan_is_detected( const uint8_t channel) Reads the current state of a configured channel, and determines if the detection criteria of the channel has been met. Table 8-12. Parameters Data direction Parameter name Description [in] channel External Interrupt channel index to check Returns Status of the requested channel's edge detection state. Table 8-13. Return Values Return value Description true If the channel's edge/level detection criteria was met false If the channel has not detected its configured criteria Function extint_chan_clear_detected() Clears the edge detection state of a configured channel. void extint_chan_clear_detected( const uint8_t channel) Clears the current state of a configured channel, readying it for the next level or edge detection. Table 8-14. Parameters 8.6.4.5 Data direction Parameter name Description [in] channel External Interrupt channel index to check Detection Testing and Clearing (NMI) Function extint_nmi_is_detected() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 149 Retrieves the edge detection state of a configured NMI channel. bool extint_nmi_is_detected( const uint8_t nmi_channel) Reads the current state of a configured NMI channel, and determines if the detection criteria of the NMI channel has been met. Table 8-15. Parameters Data direction Parameter name Description [in] nmi_channel External Interrupt NMI channel index to check Returns Status of the requested NMI channel's edge detection state. Table 8-16. Return Values Return value Description true If the NMI channel's edge/level detection criteria was met false If the NMI channel has not detected its configured criteria Function extint_nmi_clear_detected() Clears the edge detection state of a configured NMI channel. void extint_nmi_clear_detected( const uint8_t nmi_channel) Clears the current state of a configured NMI channel, readying it for the next level or edge detection. Table 8-17. Parameters 8.6.4.6 Data direction Parameter name Description [in] nmi_channel External Interrupt NMI channel index to check Callback Configuration and Initialization Function extint_register_callback() Registers an asynchronous callback function with the driver. enum status_code extint_register_callback( const extint_callback_t callback, const uint8_t channel, const enum extint_callback_type type) Registers an asynchronous callback with the EXTINT driver, fired when a channel detects the configured channel detection criteria (e.g. edge or level). Callbacks are fired once for each detected channel. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 150 Note NMI channel callbacks cannot be registered via this function; the device's NMI interrupt should be hooked directly in the user application and the NMI flags manually cleared via extint_nmi_clear_detected(). Table 8-18. Parameters Data direction Parameter name Description [in] callback Pointer to the callback function to register [in] channel Logical channel to register callback for [in] type Type of callback function to register Returns Status of the registration operation. Table 8-19. Return Values Return value Description STATUS_OK The callback was registered successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied STATUS_ERR_ALREADY_INITIALIZED Callback function has been registered, need unregister first Function extint_unregister_callback() Unregisters an asynchronous callback function with the driver. enum status_code extint_unregister_callback( const extint_callback_t callback, const uint8_t channel, const enum extint_callback_type type) Unregisters an asynchronous callback with the EXTINT driver, removing it from the internal callback registration table. Table 8-20. Parameters Returns Data direction Parameter name Description [in] callback Pointer to the callback function to unregister [in] channel Logical channel to unregister callback for [in] type Type of callback function to unregister Status of the de-registration operation. Table 8-21. Return Values Return value Description STATUS_OK The callback was Unregistered successfully AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 151 Return value Description STATUS_ERR_INVALID_ARG If an invalid callback type was supplied STATUS_ERR_BAD_ADDRESS No matching entry was found in the registration table Function extint_get_current_channel() Find what channel caused the callback. uint8_t extint_get_current_channel(void) Can be used in an EXTINT callback function to find what channel caused the callback in case same callback is used by multiple channels. Returns 8.6.4.7 Channel number. Callback Enabling and Disabling (Channel) Function extint_chan_enable_callback() Enables asynchronous callback generation for a given channel and type. enum status_code extint_chan_enable_callback( const uint8_t channel, const enum extint_callback_type type) Enables asynchronous callbacks for a given logical external interrupt channel and type. This must be called before an external interrupt channel will generate callback events. Table 8-22. Parameters Returns Data direction Parameter name Description [in] channel Logical channel to enable callback generation for [in] type Type of callback function callbacks to enable Status of the callback enable operation. Table 8-23. Return Values Return value Description STATUS_OK The callback was enabled successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied Function extint_chan_disable_callback() Disables asynchronous callback generation for a given channel and type. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 152 enum status_code extint_chan_disable_callback( const uint8_t channel, const enum extint_callback_type type) Disables asynchronous callbacks for a given logical external interrupt channel and type. Table 8-24. Parameters Returns Data direction Parameter name Description [in] channel Logical channel to disable callback generation for [in] type Type of callback function callbacks to disable Status of the callback disable operation. Table 8-25. Return Values Return value Description STATUS_OK The callback was disabled successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied 8.6.5 Enumeration Definitions 8.6.5.1 Callback Configuration and Initialization Enum extint_callback_type Enum for the possible callback types for the EXTINT module. Table 8-26. Members 8.6.5.2 Enum value Description EXTINT_CALLBACK_TYPE_DETECT Callback type for when an external interrupt detects the configured channel criteria (i.e. edge or level detection) Enum extint_detect Enum for the possible signal edge detection modes of the External Interrupt Controller module. Table 8-27. Members Enum value Description EXTINT_DETECT_NONE No edge detection. Not allowed as a NMI detection mode on some devices. EXTINT_DETECT_RISING Detect rising signal edges. EXTINT_DETECT_FALLING Detect falling signal edges. EXTINT_DETECT_BOTH Detect both signal edges. EXTINT_DETECT_HIGH Detect high signal levels. EXTINT_DETECT_LOW Detect low signal levels. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 153 8.6.5.3 Enum extint_pull Enum for the possible pin internal pull configurations. Note Disabling the internal pull resistor is not recommended if the driver is used in interrupt (callback) mode, due the possibility of floating inputs generating continuous interrupts. Table 8-28. Members Enum value Description EXTINT_PULL_UP Internal pull-up resistor is enabled on the pin. EXTINT_PULL_DOWN Internal pull-down resistor is enabled on the pin. EXTINT_PULL_NONE Internal pull resistor is disconnected from the pin. 8.7 Extra Information for EXTINT Driver 8.7.1 Acronyms The table below presents the acronyms used in this module: 8.7.2 Acronym Description EIC External Interrupt Controller MUX Multiplexer NMI Non-Maskable Interrupt Dependencies This driver has the following dependencies: ● 8.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 8.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add SAML21 support Add SAMR21 support ● Driver updated to follow driver type convention. ● Removed extint_reset(), extint_disable() and extint_enable() functions. Added internal function _system_extint_init(). ● Added configuration EXTINT_CLOCK_SOURCE in conf_extint.h. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 154 Changelog ● Removed configuration EXTINT_CALLBACKS_MAX in conf_extint.h, and added channel parameter in the register functions extint_register_callback() and extint_unregister_callback(). Updated interrupt handler to clear interrupt flag before calling callback function. Updated initialization function to also enable the digital interface clock to the module if it is disabled. Initial Release 8.8 Examples for EXTINT Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM External Interrupt Driver (EXTINT). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 8.8.1 ● Quick Start Guide for EXTINT - Basic ● Quick Start Guide for EXTINT - Callback Quick Start Guide for EXTINT - Basic The supported board list: ● SAMD20 Xplained Pro ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAML21 Xplained Pro In this use case, the EXTINT module is configured for: ● External interrupt channel connected to the board LED is used ● External interrupt channel is configured to detect both input signal edges This use case configures a physical I/O pin of the device so that it is routed to a logical External Interrupt Controller channel to detect rising and falling edges of the incoming signal. When the board button is pressed, the board LED will light up. When the board button is released, the LED will turn off. 8.8.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_extint_channel(void) { struct extint_chan_conf config_extint_chan; extint_chan_get_config_defaults(&config_extint_chan); config_extint_chan.gpio_pin config_extint_chan.gpio_pin_mux config_extint_chan.gpio_pin_pull config_extint_chan.detection_criteria = = = = BUTTON_0_EIC_PIN; BUTTON_0_EIC_MUX; EXTINT_PULL_UP; EXTINT_DETECT_BOTH; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 155 } extint_chan_set_config(BUTTON_0_EIC_LINE, &config_extint_chan); Add to user application initialization (typically the start of main()): configure_extint_channel(); Workflow 1. Create an EXTINT module channel configuration struct, which can be filled out to adjust the configuration of a single external interrupt channel. struct extint_chan_conf config_extint_chan; 2. Initialize the channel configuration struct with the module's default values. extint_chan_get_config_defaults(&config_extint_chan); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to configure the pin MUX (to route the desired physical pin to the logical channel) to the board button, and to configure the channel to detect both rising and falling edges. config_extint_chan.gpio_pin config_extint_chan.gpio_pin_mux config_extint_chan.gpio_pin_pull config_extint_chan.detection_criteria 4. = = = = BUTTON_0_EIC_PIN; BUTTON_0_EIC_MUX; EXTINT_PULL_UP; EXTINT_DETECT_BOTH; Configure external interrupt channel with the desired channel settings. extint_chan_set_config(BUTTON_0_EIC_LINE, &config_extint_chan); 8.8.1.2 Use Case Code Copy-paste the following code to your user application: while (true) { if (extint_chan_is_detected(BUTTON_0_EIC_LINE)) { // Do something in response to EXTINT edge detection bool button_pin_state = port_pin_get_input_level(BUTTON_0_PIN); port_pin_set_output_level(LED_0_PIN, button_pin_state); } } extint_chan_clear_detected(BUTTON_0_EIC_LINE); Workflow 1. Read in the current external interrupt channel state to see if an edge has been detected. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 156 if (extint_chan_is_detected(BUTTON_0_EIC_LINE)) { 2. Read in the new physical button state and mirror it on the board LED. // Do something in response to EXTINT edge detection bool button_pin_state = port_pin_get_input_level(BUTTON_0_PIN); port_pin_set_output_level(LED_0_PIN, button_pin_state); 3. Clear the detection state of the external interrupt channel so that it is ready to detect a future falling edge. extint_chan_clear_detected(BUTTON_0_EIC_LINE); 8.8.2 Quick Start Guide for EXTINT - Callback The supported board list: ● SAMD20 Xplained Pro ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAML21 Xplained Pro In this use case, the EXTINT module is configured for: ● External interrupt channel connected to the board LED is used ● External interrupt channel is configured to detect both input signal edges ● Callbacks are used to handle detections from the External Interrupt This use case configures a physical I/O pin of the device so that it is routed to a logical External Interrupt Controller channel to detect rising and falling edges of the incoming signal. A callback function is used to handle detection events from the External Interrupt module asynchronously. When the board button is pressed, the board LED will light up. When the board button is released, the LED will turn off. 8.8.2.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_extint_channel(void) { struct extint_chan_conf config_extint_chan; extint_chan_get_config_defaults(&config_extint_chan); config_extint_chan.gpio_pin = BUTTON_0_EIC_PIN; config_extint_chan.gpio_pin_mux = BUTTON_0_EIC_MUX; config_extint_chan.gpio_pin_pull = EXTINT_PULL_UP; config_extint_chan.detection_criteria = EXTINT_DETECT_BOTH; extint_chan_set_config(BUTTON_0_EIC_LINE, &config_extint_chan); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 157 } void configure_extint_callbacks(void) { extint_register_callback(extint_detection_callback, BUTTON_0_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); extint_chan_enable_callback(BUTTON_0_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); } void extint_detection_callback(void) { bool pin_state = port_pin_get_input_level(BUTTON_0_PIN); port_pin_set_output_level(LED_0_PIN, pin_state); } Add to user application initialization (typically the start of main()): configure_extint_channel(); configure_extint_callbacks(); system_interrupt_enable_global(); Workflow 1. Create an EXTINT module channel configuration struct, which can be filled out to adjust the configuration of a single external interrupt channel. struct extint_chan_conf config_extint_chan; 2. Initialize the channel configuration struct with the module's default values. extint_chan_get_config_defaults(&config_extint_chan); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to configure the pin MUX (to route the desired physical pin to the logical channel) to the board button, and to configure the channel to detect both rising and falling edges. config_extint_chan.gpio_pin config_extint_chan.gpio_pin_mux config_extint_chan.gpio_pin_pull config_extint_chan.detection_criteria 4. = = = = BUTTON_0_EIC_PIN; BUTTON_0_EIC_MUX; EXTINT_PULL_UP; EXTINT_DETECT_BOTH; Configure external interrupt channel with the desired channel settings. extint_chan_set_config(BUTTON_0_EIC_LINE, &config_extint_chan); 5. Register a callback function extint_handler() to handle detections from the External Interrupt controller. extint_register_callback(extint_detection_callback, BUTTON_0_EIC_LINE, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 158 EXTINT_CALLBACK_TYPE_DETECT); 6. Enable the registered callback function for the configured External Interrupt channel, so that it will be called by the module when the channel detects an edge. extint_chan_enable_callback(BUTTON_0_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); 7. Define the EXTINT callback that will be fired when a detection event occurs. For this example, a LED will mirror the new button state on each detection edge. void extint_detection_callback(void) { bool pin_state = port_pin_get_input_level(BUTTON_0_PIN); port_pin_set_output_level(LED_0_PIN, pin_state); } 8.8.2.2 Use Case Code Copy-paste the following code to your user application: while (true) { /* Do nothing - EXTINT will fire callback asynchronously */ } Workflow 1. External interrupt events from the driver are detected asynchronously; no special application main() code is required. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 159 9. SAM I2C Driver (SERCOM I2C) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the 2 2 device's SERCOM I C module, for the transfer of data via an I C bus. The following driver API modes are covered by this manual: ● Master Mode Polled APIs ● Master Mode Callback APIs ● Slave Mode Polled APIs ● Slave Mode Callback APIs The following peripheral is used by this module: ● SERCOM (Serial Communication Interface) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 9.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites. 9.2 Module Overview The outline of this section is as follows: ● Driver Feature Macro Definition ● Functional Description ● Bus Topology ● Transactions ● Multi Master 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 160 9.2.1 ● Bus States ● Bus Timing ● Operation in Sleep Modes Driver Feature Macro Definition Driver Feature Macro Supported devices FEATURE_I2C_FAST_MODE_PLUS_AND_HIGH_SPEED SAM D21/R21/D10/D11/L21 FEATURE_I2C_10_BIT_ADDRESS SAM D21/R21/D10/D11/L21 FEATURE_I2C_SCL_STRETCH_MODE SAM D21/R21/D10/D11/L21 FEATURE_I2C_SCL_EXTEND_TIMEOUT SAM D21/R21/D10/D11/L21 Note 9.2.2 The specific features are only available in the driver when the selected device supports those features. Functional Description 2 The I C provides a simple two-wire bidirectional bus consisting of a wired-AND type serial clock line (SCL) and a wired-AND type serial data line (SDA). 2 The I C bus provides a simple, but efficient method of interconnecting multiple master and slave devices. An arbitration mechanism is provided for resolving bus ownership between masters, as only one master device may own the bus at any given time. The arbitration mechanism relies on the wired-AND connections to avoid bus drivers short-circuiting. A unique address is assigned to all slave devices connected to the bus. A device can contain both master and slave logic, and can emulate multiple slave devices by responding to more than one address. 9.2.3 Bus Topology 2 The I C bus topology is illustrated in Figure 9-1: I2C Bus Topology on page 161. The pull-up resistors (Rs) will 2 provide a high level on the bus lines when none of the I C devices are driving the bus. These are optional, and can be replaced with a constant current source. Figure 9-1. I2C Bus Topology VCC RP RP I2C DEVICE #1 I2C DEVICE #2 I2C DEVICE #N RS RS RS RS RS RS SDA SCL 9.2.4 Note: RS is optional Transactions 2 The I C standard defines three fundamental transaction formats: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 161 ● Master Write ● ● Master Read ● ● The master transmits data packets to the slave after addressing it The slave transmits data packets to the master after being addressed Combined Read/Write ● A combined transaction consists of several write and read transactions A data transfer starts with the master issuing a Start condition on the bus, followed by the address of the slave together with a bit to indicate whether the master wants to read from or write to the slave. The addressed slave must respond to this by sending an ACK back to the master. After this, data packets are sent from the master or slave, according to the read/write bit. Each packet must be acknowledged (ACK) or not acknowledged (NACK) by the receiver. If a slave responds with a NACK, the master must assume that the slave cannot receive any more data and cancel the write operation. The master completes a transaction by issuing a Stop condition. A master can issue multiple Start conditions during a transaction; this is then called a Repeated Start condition. 9.2.4.1 Address Packets th The slave address consists of seven bits. The 8 bit in the transfer determines the data direction (read or write). An th address packet always succeeds a Start or Repeated Start condition. The 8 bit is handled in the driver, and the user will only have to provide the 7-bit address. 9.2.4.2 Data Packets Data packets are nine bits long, consisting of one 8-bit data byte, and an acknowledgement bit. Data packets follow either an address packet or another data packet on the bus. 9.2.4.3 Transaction Examples The gray bits in the following examples are sent from master to slave, and the white bits are sent from slave to master. Example of a read transaction is shown in Figure 9-2: I2C Packet Read on page 162. Here, the master first issues a Start condition and gets ownership of the bus. An address packet with the direction flag set to read is then sent and acknowledged by the slave. Then the slave sends one data packet which is acknowledged by the master. The slave sends another packet, which is not acknowledged by the master and indicates that the master will terminate the transaction. In the end, the transaction is terminated by the master issuing a Stop condition. Figure 9-2. I2C Packet Read Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 7 Bit 6 START ADDRESS Bit 8 Bit 9 Bit 10 READ ACK DATA Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 Bit 16 Bit 17 Bit 18 Bit 19 ACK DATA Bit 20 Bit 21 Bit 22 Bit 23 Bit 24 Bit 25 Bit 26 Bit 27 Bit 28 NACK STOP Example of a write transaction is shown in Figure 9-3: I2C Packet Write on page 162. Here, the master first issues a Start condition and gets ownership of the bus. An address packet with the dir flag set to write is then sent and acknowledged by the slave. Then the master sends two data packets, each acknowledged by the slave. In the end, the transaction is terminated by the master issuing a Stop condition. Figure 9-3. I2C Packet Write Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 7 Bit 6 START ADDRESS 9.2.4.4 Bit 8 Bit 9 Bit 10 WRITE ACK DATA Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 Bit 16 Bit 17 Bit 18 Bit 19 ACK DATA Bit 20 Bit 21 Bit 22 Bit 23 Bit 24 Bit 25 Bit 26 Bit 27 Bit 28 ACK STOP Packet Timeout 2 When a master sends an I C packet, there is no way of being sure that a slave will acknowledge the packet. To avoid stalling the device forever while waiting for an acknowledge, a user selectable timeout is provided in the AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 162 i2c_master_config struct which lets the driver exit a read or write operation after the specified time. The function will then return the STATUS_ERR_TIMEOUT flag. This is also the case for the slave when using the functions postfixed _wait. The time before the timeout occurs, will be the same as for unknown bus state timeout. 9.2.4.5 Repeated Start To issue a Repeated Start, the functions postfixed _no_stop must be used. These functions will not send a Stop condition when the transfer is done, thus the next transfer will start with a Repeated Start. To end the transaction, the functions without the _no_stop postfix must be used for the last read/write. 9.2.5 Multi Master In a multi master environment, arbitration of the bus is important, as only one master can own the bus at any point. 9.2.5.1 Arbitration Clock stretching The serial clock line is always driven by a master device. However, all devices connected to the bus are allowed stretch the low period of the clock to slow down the overall clock frequency or to insert wait states while processing data. Both master and slave can randomly stretch the clock, which will force the other device into a wait-state until the clock line goes high again. Arbitration on If two masters start transmitting at the same time, they will both transmit until one master detects that the data line the other master is pulling the data line low. When this is detected, the master not pulling the line low, will stop the transmission and wait until the bus is idle. As it is the master trying to contact the slave with the lowest address that will get the bus ownership, this will create an arbitration scheme always prioritizing the slaves with the lowest address in case of a bus collision. 9.2.5.2 Clock Synchronization In situations where more than one master is trying to control the bus clock line at the same time, a clock synchronization algorithm based on the same principles used for clock stretching is necessary. 9.2.6 Bus States 2 As the I C bus is limited to one transaction at the time, a master that wants to perform a bus transaction must wait until the bus is free. Because of this, it is necessary for all masters in a multi-master system to know the current status of the bus to be able to avoid conflicts and to ensure data integrity. ● IDLE No activity on the bus (between a Stop and a new Start condition) ● OWNER If the master initiates a transaction successfully ● BUSY If another master is driving the bus ● UNKNOWN If the master has recently been enabled or connected to the bus. Is forced to IDLE after given timeout when the master module is enabled. The bus state diagram can be seen in Figure 9-4: I2C Bus State Diagram on page 164. ● S: Start condition ● P: Stop condition ● Sr: Repeated start condition AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 163 Figure 9-4. I2C Bus State Diagram RESET UNKNOWN (0b00) P + Timeout Sr S IDLE (0b01) BUSY (0b11) P + Timeout Command P Write ADDR (S) Arbitration Lost OWNER (0b10) Write ADDR(Sr) 9.2.7 Bus Timing Inactive bus timeout for the master and SDA hold time is configurable in the drivers. 9.2.7.1 Unknown Bus State Timeout When a master is enabled or connected to the bus, the bus state will be unknown until either a given timeout or a stop command has occurred. The timeout is configurable in the i2c_master_config struct. The timeout time will depend on toolchain and optimization level used, as the timeout is a loop incrementing a value until it reaches the specified timeout value. 9.2.7.2 SDA Hold Timeout 2 When using the I C in slave mode, it will be important to set a SDA hold time which assures that the master will be able to pick up the bit sent from the slave. The SDA hold time makes sure that this is the case by holding the data line low for a given period after the negative edge on the clock. The SDA hold time is also available for the master driver, but is not a necessity. 9.2.8 Operation in Sleep Modes 2 The I C module can operate in all sleep modes by setting the run_in_standby Boolean in the i2c_master_config or i2c_slave_config struct. The operation in slave and master mode is shown in Table 9-1: I2C Standby Operations on page 164. Table 9-1. I2C Standby Operations Run in standby Slave Master false Disabled, all reception is dropped GCLK disabled when master is idle AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 164 Run in standby Slave Master true Wake on address match when enabled GCLK enabled while in sleep modes 9.3 Special Considerations 9.3.1 Interrupt-driven Operation While an interrupt-driven operation is in progress, subsequent calls to a write or read operation will return the STATUS_BUSY flag, indicating that only one operation is allowed at any given time. To check if another transmission can be initiated, the user can either call another transfer operation, or use the i2c_master_get_job_status/i2c_slave_get_job_status functions depending on mode. If the user would like to get callback from operations while using the interrupt-driven driver, the callback must be registered and then enabled using the "register_callback" and "enable_callback" functions. 9.4 Extra Information For extra information, see Extra Information for SERCOM I2C Driver. This includes: 9.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for SERCOM I2C Driver. 9.6 API Overview 9.6.1 Structure Definitions 9.6.1.1 Struct i2c_master_config 2 This is the configuration structure for the I C Master device. It is used as an argument for i2c_master_init to provide the desired configurations for the module. The structure should be initialized using the i2c_master_get_config_defaults . Table 9-2. Members Type Name Description uint32_t baud_rate Baud rate (in KHz) for I2C operations in standard-mode, Fast-mode and Fast-mode Plus Transfers, i2c_master_baud_rate. uint16_t buffer_timeout Timeout for packet write to wait for slave. enum gclk_generator generator_source GCLK generator to use as clock source. enum i2c_master_inactive_timeout inactive_timeout Inactive bus time out. uint32_t pinmux_pad0 PAD0 (SDA) pinmux. uint32_t pinmux_pad1 PAD1 (SCL) pinmux. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 165 9.6.1.2 Type Name Description bool run_in_standby Set to keep module active in sleep modes. bool scl_low_timeout Set to enable SCL low time-out. enum i2c_master_start_hold_time start_hold_time Bus hold time after start signal on data line. uint16_t unknown_bus_state_timeout Unknown bus state timeout. Struct i2c_master_module 2 SERCOM I C Master driver software instance structure, used to retain software state information of an associated hardware module instance. Note 9.6.1.3 The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. Struct i2c_master_packet 2 Structure to be used when transferring I C master packets. Table 9-3. Members 9.6.1.4 Type Name Description uint16_t address Address to slave device. uint8_t * data Data array containing all data to be transferred. uint16_t data_length Length of data array. bool high_speed Use high speed transfer. Set to false if the feature is not supported by the device. uint8_t hs_master_code High speed mode master code (0000 1XXX), valid when high_speed is true. bool ten_bit_address Use 10-bit addressing. Set to false if the feature is not supported by the device. Struct i2c_slave_config 2 This is the configuration structure for the I C Slave device. It is used as an argument for i2c_slave_init to provide the desired configurations for the module. The structure should be initialized using the i2c_slave_get_config_defaults. Table 9-4. Members Type Name Description uint16_t address Address or upper limit of address range. uint16_t address_mask Address mask, second address or lower limit of address range. enum i2c_slave_address_mode address_mode Addressing mode. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 166 9.6.1.5 Type Name Description uint16_t buffer_timeout Timeout to wait for master in polled functions. bool enable_general_call_address Enable general call address recognition (general call address is defined as 0000000 with direction bit 0). bool enable_nack_on_address Enable NACK on address match (this can be changed after initialization via the i2c_slave_enable_nack_on_address and i2c_slave_disable_nack_on_address functions). bool enable_scl_low_timeout Set to enable the SCL low timeout. enum gclk_generator generator_source GCLK generator to use as clock source. uint32_t pinmux_pad0 PAD0 (SDA) pinmux. uint32_t pinmux_pad1 PAD1 (SCL) pinmux. bool run_in_standby Set to keep module active in sleep modes. bool scl_low_timeout Set to enable SCL low time-out. enum i2c_slave_sda_hold_time sda_hold_time SDA hold time with respect to the negative edge of SCL. Struct i2c_slave_module 2 SERCOM I C Slave driver software instance structure, used to retain software state information of an associated hardware module instance. Note 9.6.1.6 The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. Struct i2c_slave_packet 2 Structure to be used when transferring I C slave packets. Table 9-5. Members Type Name Description uint8_t * data Data array containing all data to be transferred. uint16_t data_length Length of data array. 9.6.2 Macro Definitions 9.6.2.1 I2C Slave Status Flags 2 I C slave status flags, returned by i2c_slave_get_status() and cleared by i2c_slave_clear_status(). Macro I2C_SLAVE_STATUS_ADDRESS_MATCH AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 167 #define I2C_SLAVE_STATUS_ADDRESS_MATCH (1UL << 0) Address Match. Note Should only be cleared internally by driver. Macro I2C_SLAVE_STATUS_DATA_READY #define I2C_SLAVE_STATUS_DATA_READY (1UL << 1) Data Ready. Macro I2C_SLAVE_STATUS_STOP_RECEIVED #define I2C_SLAVE_STATUS_STOP_RECEIVED (1UL << 2) Stop Received. Macro I2C_SLAVE_STATUS_CLOCK_HOLD #define I2C_SLAVE_STATUS_CLOCK_HOLD (1UL << 3) Clock Hold. Note Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is set. Macro I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT #define I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT (1UL << 4) SCL Low Timeout. Macro I2C_SLAVE_STATUS_REPEATED_START #define I2C_SLAVE_STATUS_REPEATED_START (1UL << 5) Repeated Start. Note Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is set. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 168 Macro I2C_SLAVE_STATUS_RECEIVED_NACK #define I2C_SLAVE_STATUS_RECEIVED_NACK (1UL << 6) Received not acknowledge. Note Cannot be cleared. Macro I2C_SLAVE_STATUS_COLLISION #define I2C_SLAVE_STATUS_COLLISION (1UL << 7) Transmit Collision. Macro I2C_SLAVE_STATUS_BUS_ERROR #define I2C_SLAVE_STATUS_BUS_ERROR (1UL << 8) Bus error. 9.6.3 Function Definitions 9.6.3.1 Lock/Unlock Function i2c_master_lock() Attempt to get lock on driver instance. enum status_code i2c_master_lock( struct i2c_master_module *const module) This function checks the instance's lock, which indicates whether or not it is currently in use, and sets the lock if it was not already set. The purpose of this is to enable exclusive access to driver instances, so that, e.g., transactions by different services will not interfere with each other. Table 9-6. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 9-7. Return Values Return value Description STATUS_OK If the module was locked STATUS_BUSY If the module was already locked AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 169 Function i2c_master_unlock() Unlock driver instance. void i2c_master_unlock( struct i2c_master_module *const module) This function clears the instance lock, indicating that it is available for use. Table 9-8. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 9-9. Return Values 9.6.3.2 Return value Description STATUS_OK If the module was locked STATUS_BUSY If the module was already locked Configuration and Initialization Function i2c_master_is_syncing() Returns the synchronization status of the module. bool i2c_master_is_syncing( const struct i2c_master_module *const module) Returns the synchronization status of the module. Table 9-10. Parameters Data direction Parameter name Description [in] module Pointer to software module structure Returns Status of the synchronization. Table 9-11. Return Values Return value Description true Module is busy synchronizing false Module is not synchronizing Function i2c_master_get_config_defaults() Gets the I2C master default configurations. void i2c_master_get_config_defaults( struct i2c_master_config *const config) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 170 Use to initialize the configuration structure to known default values. The default configuration is as follows: ● Baudrate 100KHz ● GCLK generator 0 ● Do not run in standby ● Start bit hold time 300ns - 600ns ● Buffer timeout = 65535 ● Unknown bus status timeout = 65535 ● Do not run in standby ● PINMUX_DEFAULT for SERCOM pads Those default configuration only availale if the device supports it: ● High speed baudrate 3.4MHz ● Standard-mode and Fast-mode transfer speed ● SCL stretch disabled ● slave SCL low extend time-out disabled ● maser SCL low extend time-out disabled Table 9-12. Parameters Data direction Parameter name Description [out] config Pointer to configuration structure to be initiated Function i2c_master_init() Initializes the requested I2C hardware module. enum status_code i2c_master_init( struct i2c_master_module *const module, Sercom *const hw, const struct i2c_master_config *const config) 2 2 Support and FAQ: visit Atmel Support Initializes the SERCOM I C master device requested and sets the provided software module struct. Run this function before any further use of the driver. Table 9-13. Parameters 2 Data direction Parameter name Description [out] module Pointer to software module struct [in] hw Pointer to the hardware instance [in] config Pointer to the configuration struct http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 171 Returns Status of initialization. Table 9-14. Return Values Return value Description STATUS_OK Module initiated correctly STATUS_ERR_DENIED If module is enabled STATUS_BUSY If module is busy resetting STATUS_ERR_ALREADY_INITIALIZED If setting other GCLK generator than previously set STATUS_ERR_BAUDRATE_UNAVAILABLE If given baudrate is not compatible with set GCLK frequency 2 Initializes the SERCOM I C master device requested and sets the provided software module struct. Run this function before any further use of the driver. Table 9-15. Parameters Data direction Parameter name Description [out] module Pointer to software module struct [in] hw Pointer to the hardware instance [in] config Pointer to the configuration struct Returns Status of initialization. Table 9-16. Return Values Return value Description STATUS_OK Module initiated correctly STATUS_ERR_DENIED If module is enabled STATUS_BUSY If module is busy resetting STATUS_ERR_ALREADY_INITIALIZED If setting other GCLK generator than previously set STATUS_ERR_BAUDRATE_UNAVAILABLE If given baudrate is not compatible with set GCLK frequency Function i2c_master_enable() Enables the I2C module. void i2c_master_enable( const struct i2c_master_module *const module) 2 Enables the requested I C module and set the bus state to IDLE after the specified timeout period if no stop bit is detected. Table 9-17. Parameters Data direction Parameter name Description [in] module Pointer to the software module struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 172 Function i2c_master_disable() Disable the I2C module. void i2c_master_disable( const struct i2c_master_module *const module) 2 Disables the requested I C module. Table 9-18. Parameters Data direction Parameter name Description [in] module Pointer to the software module struct Function i2c_master_reset() Resets the hardware module. void i2c_master_reset( struct i2c_master_module *const module) Reset the module to hardware defaults. Table 9-19. Parameters 9.6.3.3 Data direction Parameter name Description [in, out] module Pointer to software module structure Read and Write Function i2c_master_read_packet_wait() Reads data packet from slave. enum status_code i2c_master_read_packet_wait( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Reads a data packet from the specified slave address on the I C bus and sends a stop condition when finished. Note This will stall the device from any other operation. For interrupt-driven operation, see i2c_master_read_packet_job. Table 9-20. Parameters Data direction Parameter name Description [in, out] module Pointer to software module struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 173 Returns Data direction Parameter name Description [in, out] packet Pointer to I C packet to transfer 2 Status of reading packet. Table 9-21. Return Values Return value Description STATUS_OK The packet was read successfully STATUS_ERR_TIMEOUT If no response was given within specified timeout period STATUS_ERR_DENIED If error on bus STATUS_ERR_PACKET_COLLISION If arbitration is lost STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave acknowledged the address Function i2c_master_read_packet_wait_no_stop() Reads data packet from slave without sending a stop condition when done. enum status_code i2c_master_read_packet_wait_no_stop( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Reads a data packet from the specified slave address on the I C bus without sending a stop condition when done, thus retaining ownership of the bus when done. To end the transaction, a read or write with stop condition must be performed. Note This will stall the device from any other operation. For interrupt-driven operation, see i2c_master_read_packet_job. Table 9-22. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 Status of reading packet. Table 9-23. Return Values Return value Description STATUS_OK The packet was read successfully STATUS_ERR_TIMEOUT If no response was given within specified timeout period STATUS_ERR_DENIED If error on bus STATUS_ERR_PACKET_COLLISION If arbitration is lost AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 174 Return value Description STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave acknowledged the address Function i2c_master_write_packet_wait() Writes data packet to slave. enum status_code i2c_master_write_packet_wait( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Writes a data packet to the specified slave address on the I C bus and sends a stop condition when finished. Note This will stall the device from any other operation. For interrupt-driven operation, see i2c_master_read_packet_job. Table 9-24. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 Status of reading packet. Table 9-25. Return Values Return value Description STATUS_OK If packet was read STATUS_BUSY If master module is busy with a job STATUS_ERR_DENIED If error on bus STATUS_ERR_PACKET_COLLISION If arbitration is lost STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave acknowledged the address STATUS_ERR_TIMEOUT If timeout occurred STATUS_ERR_OVERFLOW If slave did not acknowledge last sent data, indicating that slave does not want more data and was not able to read last data sent Function i2c_master_write_packet_wait_no_stop() Writes data packet to slave without sending a stop condition when done. enum status_code i2c_master_write_packet_wait_no_stop( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Writes a data packet to the specified slave address on the I C bus without sending a stop condition, thus retaining ownership of the bus when done. To end the transaction, a read or write with stop condition or sending a stop with the i2c_master_send_stop function must be performed. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 175 Note This will stall the device from any other operation. For interrupt-driven operation, see i2c_master_read_packet_job. Table 9-26. Parameters Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer Returns 2 Status of reading packet. Table 9-27. Return Values Return value Description STATUS_OK If packet was read STATUS_BUSY If master module is busy STATUS_ERR_DENIED If error on bus STATUS_ERR_PACKET_COLLISION If arbitration is lost STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave acknowledged the address STATUS_ERR_TIMEOUT If timeout occurred STATUS_ERR_OVERFLOW If slave did not acknowledge last sent data, indicating that slave do not want more data Function i2c_master_send_stop() Sends stop condition on bus. void i2c_master_send_stop( struct i2c_master_module *const module) Sends a stop condition on bus. Note This function can only be used after the i2c_master_write_packet_wait_no_stop function. If a stop condition is to be sent after a read, the i2c_master_read_packet_wait function must be used. Table 9-28. Parameters 9.6.3.4 Data direction Parameter name Description [in] module Pointer to the software instance struct Callbacks Function i2c_master_register_callback() Registers callback for the specified callback type. void i2c_master_register_callback( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 176 struct i2c_master_module *const module, i2c_master_callback_t callback, enum i2c_master_callback callback_type) Associates the given callback function with the specified callback type. To enable the callback, the i2c_master_enable_callback function must be used. Table 9-29. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback Pointer to the function desired for the specified callback [in] callback_type Callback type to register Function i2c_master_unregister_callback() Unregisters callback for the specified callback type. void i2c_master_unregister_callback( struct i2c_master_module *const module, enum i2c_master_callback callback_type) When called, the currently registered callback for the given callback type will be removed. Table 9-30. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Specifies the callback type to unregister Function i2c_master_enable_callback() Enables callback. void i2c_master_enable_callback( struct i2c_master_module *const module, enum i2c_master_callback callback_type) Enables the callback specified by the callback_type. Table 9-31. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Callback type to enable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 177 Function i2c_master_disable_callback() Disables callback. void i2c_master_disable_callback( struct i2c_master_module *const module, enum i2c_master_callback callback_type) Disables the callback specified by the callback_type. Table 9-32. Parameters 9.6.3.5 Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Callback type to disable Read and Write, Interrupt-Driven Function i2c_master_read_packet_job() Initiates a read packet operation. enum status_code i2c_master_read_packet_job( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Reads a data packet from the specified slave address on the I C bus. This is the non-blocking equivalent of i2c_master_read_packet_wait. Table 9-33. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Status of starting reading I C packet. Table 9-34. Return Values Return value Description STATUS_OK If reading was started successfully STATUS_BUSY If module is currently busy with another transfer Function i2c_master_read_packet_job_no_stop() Initiates a read packet operation without sending a STOP condition when done. enum status_code i2c_master_read_packet_job_no_stop( struct i2c_master_module *const module, struct i2c_master_packet *const packet) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 178 2 Reads a data packet from the specified slave address on the I C bus without sending a stop condition, thus retaining ownership of the bus when done. To end the transaction, a read or write with stop condition must be performed. This is the non-blocking equivalent of i2c_master_read_packet_wait_no_stop. Table 9-35. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Status of starting reading I C packet. Table 9-36. Return Values Return value Description STATUS_OK If reading was started successfully STATUS_BUSY If module is currently busy with another operation Function i2c_master_write_packet_job() Initiates a write packet operation. enum status_code i2c_master_write_packet_job( struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Writes a data packet to the specified slave address on the I C bus. This is the non-blocking equivalent of i2c_master_write_packet_wait. Table 9-37. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Status of starting writing I C packet job. Table 9-38. Return Values Return value Description STATUS_OK If writing was started successfully STATUS_BUSY If module is currently busy with another transfer Function i2c_master_write_packet_job_no_stop() Initiates a write packet operation without sending a STOP condition when done. enum status_code i2c_master_write_packet_job_no_stop( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 179 struct i2c_master_module *const module, struct i2c_master_packet *const packet) 2 Writes a data packet to the specified slave address on the I C bus without sending a stop condition, thus retaining ownership of the bus when done. To end the transaction, a read or write with stop condition or sending a stop with the i2c_master_send_stop function must be performed. This is the non-blocking equivalent of i2c_master_write_packet_wait_no_stop. Table 9-39. Parameters Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Returns Status of starting writing I C packet job. Table 9-40. Return Values Return value Description STATUS_OK If writing was started successfully STATUS_BUSY If module is currently busy with another Function i2c_master_cancel_job() Cancel any currently ongoing operation. void i2c_master_cancel_job( struct i2c_master_module *const module) Terminates the running transfer operation. Table 9-41. Parameters Data direction Parameter name Description [in, out] module Pointer to software module structure Function i2c_master_get_job_status() Get status from ongoing job. enum status_code i2c_master_get_job_status( struct i2c_master_module *const module) Will return the status of a transfer operation. Table 9-42. Parameters Data direction Parameter name Description [in] module Pointer to software module structure AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 180 Returns Last status code from transfer operation. Table 9-43. Return Values 9.6.3.6 Return value Description STATUS_OK No error has occurred STATUS_BUSY If transfer is in progress STATUS_BUSY If master module is busy STATUS_ERR_DENIED If error on bus STATUS_ERR_PACKET_COLLISION If arbitration is lost STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave acknowledged the address STATUS_ERR_TIMEOUT If timeout occurred STATUS_ERR_OVERFLOW If slave did not acknowledge last sent data, indicating that slave does not want more data and was not able to read Lock/Unlock Function i2c_slave_lock() Attempt to get lock on driver instance. enum status_code i2c_slave_lock( struct i2c_slave_module *const module) This function checks the instance's lock, which indicates whether or not it is currently in use, and sets the lock if it was not already set. The purpose of this is to enable exclusive access to driver instances, so that, e.g., transactions by different services will not interfere with each other. Table 9-44. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 9-45. Return Values Return value Description STATUS_OK If the module was locked STATUS_BUSY If the module was already locked Function i2c_slave_unlock() Unlock driver instance. void i2c_slave_unlock( struct i2c_slave_module *const module) This function clears the instance lock, indicating that it is available for use. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 181 Table 9-46. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 9-47. Return Values 9.6.3.7 Return value Description STATUS_OK If the module was locked STATUS_BUSY If the module was already locked Configuration and Initialization Function i2c_slave_is_syncing() Returns the synchronization status of the module. bool i2c_slave_is_syncing( const struct i2c_slave_module *const module) Returns the synchronization status of the module. Table 9-48. Parameters Data direction Parameter name Description [out] module Pointer to software module structure Returns Status of the synchronization. Table 9-49. Return Values Return value Description true Module is busy synchronizing false Module is not synchronizing Function i2c_slave_get_config_defaults() Gets the I2C slave default configurations. void i2c_slave_get_config_defaults( struct i2c_slave_config *const config) This will initialize the configuration structure to known default values. The default configuration is as follows: ● Disable SCL low timeout ● 300ns - 600ns SDA hold time ● Buffer timeout = 65535 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 182 ● Address with mask ● Address = 0 ● Address mask = 0 (one single address) ● General call address disabled ● Address nack disabled if the interrupt driver is used ● GCLK generator 0 ● Do not run in standby ● PINMUX_DEFAULT for SERCOM pads Those default configuration only availale if the device supports it: ● Not using 10-bit addressing ● Standard-mode and Fast-mode transfer speed ● SCL stretch disabled ● slave SCL low extend time-out disabled Table 9-50. Parameters Data direction Parameter name Description [out] config Pointer to configuration structure to be initialized Function i2c_slave_init() Initializes the requested I2C hardware module. enum status_code i2c_slave_init( struct i2c_slave_module *const module, Sercom *const hw, const struct i2c_slave_config *const config) 2 Initializes the SERCOM I C Slave device requested and sets the provided software module struct. Run this function before any further use of the driver. Table 9-51. Parameters Returns Data direction Parameter name Description [out] module Pointer to software module struct [in] hw Pointer to the hardware instance [in] config Pointer to the configuration struct Status of initialization. Table 9-52. Return Values Return value Description STATUS_OK Module initiated correctly AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 183 Return value Description STATUS_ERR_DENIED If module is enabled STATUS_BUSY If module is busy resetting STATUS_ERR_ALREADY_INITIALIZED If setting other GCLK generator than previously set Function i2c_slave_enable() Enables the I2C module. void i2c_slave_enable( const struct i2c_slave_module *const module) 2 This will enable the requested I C module. Table 9-53. Parameters Data direction Parameter name Description [in] module Pointer to the software module struct Function i2c_slave_disable() Disables the I2C module. void i2c_slave_disable( const struct i2c_slave_module *const module) 2 This will disable the I C module specified in the provided software module structure. Table 9-54. Parameters Data direction Parameter name Description [in] module Pointer to the software module struct Function i2c_slave_reset() Resets the hardware module. void i2c_slave_reset( struct i2c_slave_module *const module) This will reset the module to hardware defaults. Table 9-55. Parameters Data direction Parameter name Description [in, out] module Pointer to software module structure AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 184 9.6.3.8 Read and Write Function i2c_slave_write_packet_wait() Writes a packet to the master. enum status_code i2c_slave_write_packet_wait( struct i2c_slave_module *const module, struct i2c_slave_packet *const packet) Writes a packet to the master. This will wait for the master to issue a request. Table 9-56. Parameters Data direction Parameter name Description [in] module Pointer to software module structure [in] packet Packet to write to master Returns Status of packet write. Table 9-57. Return Values Return value Description STATUS_OK Packet was written successfully STATUS_ERR_DENIED Start condition not received, another interrupt flag is set STATUS_ERR_IO There was an error in the previous transfer STATUS_ERR_BAD_FORMAT Master wants to write data STATUS_ERR_INVALID_ARG Invalid argument(s) was provided STATUS_ERR_BUSY The I C module is busy with a job. STATUS_ERR_ERR_OVERFLOW Master NACKed before entire packet was transferred STATUS_ERR_TIMEOUT No response was given within the timeout period 2 Writes a packet to the master. This will wait for the master to issue a request. Table 9-58. Parameters Returns Data direction Parameter name Description [in] module Pointer to software module structure [in] packet Packet to write to master Status of packet write. Table 9-59. Return Values Return value Description STATUS_OK Packet was written successfully STATUS_ERR_DENIED Start condition not received, another interrupt flag is set AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 185 Return value Description STATUS_ERR_IO There was an error in the previous transfer STATUS_ERR_BAD_FORMAT Master wants to write data STATUS_ERR_INVALID_ARG Invalid argument(s) was provided STATUS_ERR_BUSY The I C module is busy with a job STATUS_ERR_ERR_OVERFLOW Master NACKed before entire packet was transferred STATUS_ERR_TIMEOUT No response was given within the timeout period 2 Function i2c_slave_read_packet_wait() Reads a packet from the master. enum status_code i2c_slave_read_packet_wait( struct i2c_slave_module *const module, struct i2c_slave_packet *const packet) Reads a packet from the master. This will wait for the master to issue a request. Table 9-60. Parameters Returns Data direction Parameter name Description [in] module Pointer to software module structure [out] packet Packet to read from master Status of packet read. Table 9-61. Return Values Return value Description STATUS_OK Packet was read successfully STATUS_ABORTED Master sent stop condition or repeated start before specified length of bytes was received STATUS_ERR_IO There was an error in the previous transfer STATUS_ERR_DENIED Start condition not received, another interrupt flag is set STATUS_ERR_INVALID_ARG Invalid argument(s) was provided STATUS_ERR_BUSY The I C module is busy with a job STATUS_ERR_BAD_FORMAT Master wants to read data STATUS_ERR_ERR_OVERFLOW Last byte received overflows buffer 2 Function i2c_slave_get_direction_wait() Waits for a start condition on the bus. enum i2c_slave_direction i2c_slave_get_direction_wait( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 186 struct i2c_slave_module *const module) Waits for the master to issue a start condition on the bus. Note that this function does not check for errors in the last transfer, this will be discovered when reading or writing. Table 9-62. Parameters Data direction Parameter name Description [in] module Pointer to software module structure Returns Direction of the current transfer, when in slave mode. Table 9-63. Return Values Return value Description I2C_SLAVE_DIRECTION_NONE No request from master within timeout period I2C_SLAVE_DIRECTION_READ Write request from master I2C_SLAVE_DIRECTION_WRITE Read request from master Note This function is only available for 7-bit slave addressing. Waits for the master to issue a start condition on the bus. Note that this function does not check for errors in the last transfer, this will be discovered when reading or writing. Table 9-64. Parameters Returns Data direction Parameter name Description [in] module Pointer to software module structure Direction of the current transfer, when in slave mode. Table 9-65. Return Values 9.6.3.9 Return value Description I2C_SLAVE_DIRECTION_NONE No request from master within timeout period I2C_SLAVE_DIRECTION_READ Write request from master I2C_SLAVE_DIRECTION_WRITE Read request from master Status Management Function i2c_slave_get_status() Retrieves the current module status. uint32_t i2c_slave_get_status( struct i2c_slave_module *const module) Checks the status of the module and returns it as a bitmask of status flags. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 187 Table 9-66. Parameters Data direction Parameter name Description [in] module Pointer to the I C slave software device struct Returns 2 Bitmask of status flags. Table 9-67. Return Values Return value Description I2C_SLAVE_STATUS_ADDRESS_MATCH A valid address has been received I2C_SLAVE_STATUS_DATA_READY A I C slave byte transmission is successfully completed I2C_SLAVE_STATUS_STOP_RECEIVED A stop condition is detected for a transaction being processed I2C_SLAVE_STATUS_CLOCK_HOLD The slave is holding the SCL line low I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT An SCL low time-out has occurred I2C_SLAVE_STATUS_REPEATED_START Indicates a repeated start, only valid if I2C_SLAVE_STATUS_ADDRESS_MATCH is set I2C_SLAVE_STATUS_RECEIVED_NACK The last data packet sent was not acknowledged I2C_SLAVE_STATUS_COLLISION The I C slave was not able to transmit a high data or NACK bit I2C_SLAVE_STATUS_BUS_ERROR An illegal bus condition has occurred on the bus 2 2 Function i2c_slave_clear_status() Clears a module status flag. void i2c_slave_clear_status( struct i2c_slave_module *const module, uint32_t status_flags) Clears the given status flag of the module. Note Not all status flags can be cleared. Table 9-68. Parameters Data direction Parameter name Description [in] module Pointer to the I C software device struct [in] status_flags Bit mask of status flags to clear 2 9.6.3.10 Address Match Functionality Function i2c_slave_enable_nack_on_address() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 188 Enables sending of NACK on address match. void i2c_slave_enable_nack_on_address( struct i2c_slave_module *const module) 3 Support and FAQ: visit Atmel Support Enables sending of NACK on address match, thus discarding any incoming transaction. Table 9-69. Parameters Data direction Parameter name Description [in, out] module Pointer to software module structure Function i2c_slave_disable_nack_on_address() Disables sending NACK on address match. void i2c_slave_disable_nack_on_address( struct i2c_slave_module *const module) Disables sending of NACK on address match, thus acknowledging incoming transactions. Table 9-70. Parameters Data direction Parameter name Description [in, out] module Pointer to software module structure 9.6.3.11 Callbacks Function i2c_slave_register_callback() Registers callback for the specified callback type. void i2c_slave_register_callback( struct i2c_slave_module *const module, i2c_slave_callback_t callback, enum i2c_slave_callback callback_type) Associates the given callback function with the specified callback type. To enable the callback, the i2c_slave_enable_callback function must be used. Table 9-71. Parameters 3 Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback Pointer to the function desired for the specified callback [in] callback_type Callback type to register http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 189 Function i2c_slave_unregister_callback() Unregisters callback for the specified callback type. void i2c_slave_unregister_callback( struct i2c_slave_module *const module, enum i2c_slave_callback callback_type) Removes the currently registered callback for the given callback type. Table 9-72. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Callback type to unregister Function i2c_slave_enable_callback() Enables callback. void i2c_slave_enable_callback( struct i2c_slave_module *const module, enum i2c_slave_callback callback_type) Enables the callback specified by the callback_type. Table 9-73. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Callback type to enable Function i2c_slave_disable_callback() Disables callback. void i2c_slave_disable_callback( struct i2c_slave_module *const module, enum i2c_slave_callback callback_type) Disables the callback specified by the callback_type. Table 9-74. Parameters Data direction Parameter name Description [in, out] module Pointer to the software module struct [in] callback_type Callback type to disable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 190 9.6.3.12 Read and Write, Interrupt-Driven Function i2c_slave_read_packet_job() Initiates a reads packet operation. enum status_code i2c_slave_read_packet_job( struct i2c_slave_module *const module, struct i2c_slave_packet *const packet) Reads a data packet from the master. A write request must be initiated by the master before the packet can be read. The I2C_SLAVE_CALLBACK_WRITE_REQUEST on page 194 callback can be used to call this function. Table 9-75. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Status of starting asynchronously reading I C packet. Table 9-76. Return Values Return value Description STATUS_OK If reading was started successfully STATUS_BUSY If module is currently busy with another transfer Function i2c_slave_write_packet_job() Initiates a write packet operation. enum status_code i2c_slave_write_packet_job( struct i2c_slave_module *const module, struct i2c_slave_packet *const packet) Writes a data packet to the master. A read request must be initiated by the master before the packet can be written. The I2C_SLAVE_CALLBACK_READ_REQUEST on page 194 callback can be used to call this function. Table 9-77. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module struct [in, out] packet Pointer to I C packet to transfer 2 2 Status of starting writing I C packet. Table 9-78. Return Values Return value Description STATUS_OK If writing was started successfully STATUS_BUSY If module is currently busy with another transfer AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 191 Function i2c_slave_cancel_job() Cancels any currently ongoing operation. void i2c_slave_cancel_job( struct i2c_slave_module *const module) Terminates the running transfer operation. Table 9-79. Parameters Data direction Parameter name Description [in, out] module Pointer to software module structure Function i2c_slave_get_job_status() Gets status of ongoing job. enum status_code i2c_slave_get_job_status( struct i2c_slave_module *const module) Will return the status of the ongoing job, or the error that occurred in the last transfer operation. The status will be cleared when starting a new job. Table 9-80. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to software module structure Status of job. Table 9-81. Return Values Return value Description STATUS_OK No error has occurred STATUS_BUSY Transfer is in progress STATUS_ERR_IO A collision, timeout or bus error happened in the last transfer STATUS_ERR_TIMEOUT A timeout occurred STATUS_ERR_OVERFLOW Data from master overflows receive buffer 9.6.4 Enumeration Definitions 9.6.4.1 Enum i2c_master_baud_rate 2 Values for I C speeds supported by the module. The driver will also support setting any other value, in which case set the value in the i2c_master_config at desired value divided by 1000. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 192 Example: If 10KHz operation is required, give baud_rate in the configuration structure the value 10. Table 9-82. Members 9.6.4.2 Enum value Description I2C_MASTER_BAUD_RATE_100KHZ Baud rate at 100KHz (Standard-mode). I2C_MASTER_BAUD_RATE_400KHZ Baud rate at 400KHz (Fast-mode). Enum i2c_master_callback 2 The available callback types for the I C master module. Table 9-83. Members 9.6.4.3 Enum value Description I2C_MASTER_CALLBACK_WRITE_COMPLETE Callback for packet write complete. I2C_MASTER_CALLBACK_READ_COMPLETE Callback for packet read complete. I2C_MASTER_CALLBACK_ERROR Callback for error. Enum i2c_master_inactive_timeout \ brief Values for inactive bus time-out. If the inactive bus time-out is enabled and the bus is inactive for longer than the time-out setting, the bus state logic will be set to idle. Table 9-84. Members 9.6.4.4 Enum value Description I2C_MASTER_INACTIVE_TIMEOUT_DISABLED Inactive bus time-out disabled. I2C_MASTER_INACTIVE_TIMEOUT_55US Inactive bus time-out 5-6 SCL cycle time-out. I2C_MASTER_INACTIVE_TIMEOUT_105US Inactive bus time-out 10-11 SCL cycle time-out. I2C_MASTER_INACTIVE_TIMEOUT_205US Inactive bus time-out 20-21 SCL cycle time-out. Enum i2c_master_interrupt_flag Flags used when reading or setting interrupt flags. Table 9-85. Members 9.6.4.5 Enum value Description I2C_MASTER_INTERRUPT_WRITE Interrupt flag used for write. I2C_MASTER_INTERRUPT_READ Interrupt flag used for read. Enum i2c_master_start_hold_time 2 Values for the possible I C master mode SDA internal hold times after start bit has been sent. Table 9-86. Members Enum value Description I2C_MASTER_START_HOLD_TIME_DISABLED Internal SDA hold time disabled. I2C_MASTER_START_HOLD_TIME_50NS_100NS Internal SDA hold time 50ns - 100ns. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 193 9.6.4.6 Enum value Description I2C_MASTER_START_HOLD_TIME_300NS_600NS Internal SDA hold time 300ns - 600ns. I2C_MASTER_START_HOLD_TIME_400NS_800NS Internal SDA hold time 400ns - 800ns. Enum i2c_slave_address_mode Enum for the possible address modes. Table 9-87. Members 9.6.4.7 Enum value Description I2C_SLAVE_ADDRESS_MODE_MASK Address match on address_mask used as a mask to address. I2C_SLAVE_ADDRESS_MODE_TWO_ADDRESSES Address math on both address and address_mask. I2C_SLAVE_ADDRESS_MODE_RANGE Address match on range of addresses between and including address and address_mask. Enum i2c_slave_callback 2 The available callback types for the I C slave. Table 9-88. Members 9.6.4.8 Enum value Description I2C_SLAVE_CALLBACK_WRITE_COMPLETE Callback for packet write complete. I2C_SLAVE_CALLBACK_READ_COMPLETE Callback for packet read complete. I2C_SLAVE_CALLBACK_READ_REQUEST Callback for read request from master - can be used to issue a write. I2C_SLAVE_CALLBACK_WRITE_REQUEST Callback for write request from master - can be used to issue a read. I2C_SLAVE_CALLBACK_ERROR Callback for error. I2C_SLAVE_CALLBACK_ERROR_LAST_TRANSFER Callback for error in last transfer. Discovered on a new address interrupt. Enum i2c_slave_direction Enum for the direction of a request. Table 9-89. Members 9.6.4.9 Enum value Description I2C_SLAVE_DIRECTION_READ Read. I2C_SLAVE_DIRECTION_WRITE Write. I2C_SLAVE_DIRECTION_NONE No direction. Enum i2c_slave_sda_hold_time Enum for the possible SDA hold times with respect to the negative edge of SCL. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 194 Table 9-90. Members Enum value Description I2C_SLAVE_SDA_HOLD_TIME_DISABLED SDA hold time disabled. I2C_SLAVE_SDA_HOLD_TIME_50NS_100NS SDA hold time 50ns - 100ns. I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS SDA hold time 300ns - 600ns. I2C_SLAVE_SDA_HOLD_TIME_400NS_800NS SDA hold time 400ns - 800ns. 9.6.4.10 Enum i2c_transfer_direction For master: transfer direction or setting direction bit in address. For slave: direction of request from master. Table 9-91. Members Enum value Description I2C_TRANSFER_WRITE Master write operation is in progress. I2C_TRANSFER_READ Master read operation is in progress. 9.7 Extra Information for SERCOM I2C Driver 9.7.1 Acronyms Table 9-92: Acronyms on page 195 is a table listing the acronyms used in this module, along with their intended meanings. Table 9-92. Acronyms 9.7.2 Acronym Description SDA Serial Data Line SCL Serial Clock Line SERCOM Serial Communication Interface DMA Direct Memory Access Dependencies 2 The I C driver has the following dependencies: ● 9.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 9.7.4 Module History Table 9-93: Module History on page 195 is an overview of the module history, detailing enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version listed in Table 9-93: Module History on page 195. Table 9-93. Module History Changelog ● Added 10-bit addressing and high speed support in SAM D21 ● Seperate structure i2c_packet into i2c_master_packet and i2c_slave packet ● Added support for SCL stretch and extended timeout hardware features in SAM D21 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 195 Changelog ● Added fast mode plus support in SAM D21 2 Fixed incorrect logical mask for determining if a bus error has occurred in I C Slave mode Initial Release 9.8 Examples for SERCOM I2C Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM I2C Driver (SERCOM I2C). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 9.8.1 ● Quick Start Guide for the I2C Master module - Basic Use Case ● Quick Start Guide for the I2C Master module - Callback Use Case ● Quick Start Guide for the I2C Master module - DMA Use Case ● Quick Start Guide for the I2C Slave module - Basic Use Case ● Quick Start Guide for the I2C Slave module - Callback Use Case ● Quick Start Guide for the I2C Slave module - DMA Use Case Quick Start Guide for SERCOM I2C Master - Basic 2 In this use case, the I C will used and set up as follows: 9.8.1.1 ● Master mode ● 100KHz operation speed ● Not operational in standby ● 10000 packet timeout value ● 65535 unknown bus state timeout value Prerequisites 2 The device must be connected to an I C slave. 9.8.1.2 Setup Code The following must be added to the user application: ● A sample buffer to send, a sample buffer to read: #define DATA_LENGTH 10 static uint8_t write_buffer[DATA_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, }; static uint8_t read_buffer[DATA_LENGTH]; ● Slave address to access: #define SLAVE_ADDRESS 0x12 ● Number of times to try to send packet if it fails: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 196 #define TIMEOUT 1000 ● Globally accessible module structure: struct i2c_master_module i2c_master_instance; ● Function for setting up the module: void configure_i2c_master(void) { /* Initialize config structure and software module. */ struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); /* Change buffer timeout to something longer. */ config_i2c_master.buffer_timeout = 10000; /* Initialize and enable device with config. */ i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master); } ● i2c_master_enable(&i2c_master_instance); Add to user application main(): /* Configure device and enable. */ configure_i2c_master(); /* Timeout counter. */ uint16_t timeout = 0; /* Init i2c packet. */ struct i2c_master_packet packet = { .address = SLAVE_ADDRESS, .data_length = DATA_LENGTH, .data = write_buffer, .ten_bit_address = false, .high_speed = false, .hs_master_code = 0x0, }; Workflow 1. Configure and enable module. void configure_i2c_master(void) { /* Initialize config structure and software module. */ struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); /* Change buffer timeout to something longer. */ config_i2c_master.buffer_timeout = 10000; /* Initialize and enable device with config. */ i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 197 } a. i2c_master_enable(&i2c_master_instance); Create and initialize configuration structure. struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); b. Change settings in the configuration. config_i2c_master.buffer_timeout = 10000; c. Initialize the module with the set configurations. i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master); d. Enable the module. i2c_master_enable(&i2c_master_instance); 2. Create a variable to see when we should stop trying to send packet. uint16_t timeout = 0; 3. Create a packet to send. struct i2c_master_packet packet = { .address = SLAVE_ADDRESS, .data_length = DATA_LENGTH, .data = write_buffer, .ten_bit_address = false, .high_speed = false, .hs_master_code = 0x0, }; 9.8.1.3 Implementation Code Add to user application main(): /* Write buffer to slave until success. */ while (i2c_master_write_packet_wait(&i2c_master_instance, &packet) != STATUS_OK) { /* Increment timeout counter and check if timed out. */ if (timeout++ == TIMEOUT) { break; } } /* Read from slave until success. */ packet.data = read_buffer; while (i2c_master_read_packet_wait(&i2c_master_instance, &packet) != STATUS_OK) { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 198 /* Increment timeout counter and check if timed out. */ if (timeout++ == TIMEOUT) { break; } } Workflow 1. Write packet to slave. while (i2c_master_write_packet_wait(&i2c_master_instance, &packet) != STATUS_OK) { /* Increment timeout counter and check if timed out. */ if (timeout++ == TIMEOUT) { break; } } The module will try to send the packet TIMEOUT number of times or until it is successfully sent. 2. Read packet from slave. packet.data = read_buffer; while (i2c_master_read_packet_wait(&i2c_master_instance, &packet) != STATUS_OK) { /* Increment timeout counter and check if timed out. */ if (timeout++ == TIMEOUT) { break; } } The module will try to read the packet TIMEOUT number of times or until it is successfully read. 9.8.2 Quick Start Guide for SERCOM I2C Master - Callback 2 In this use case, the I C will used and set up as follows: 9.8.2.1 ● Master mode ● 100KHz operation speed ● Not operational in standby ● 65535 unknown bus state timeout value Prerequisites 2 The device must be connected to an I C slave. 9.8.2.2 Setup Code The following must be added to the user application: A sample buffer to write from, a reversed buffer to write from and length of buffers. #define DATA_LENGTH 8 static uint8_t wr_buffer[DATA_LENGTH] = { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 199 }; 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 static uint8_t wr_buffer_reversed[DATA_LENGTH] = { 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00 }; static uint8_t rd_buffer[DATA_LENGTH]; Address of slave: #define SLAVE_ADDRESS 0x12 Globally accessible module structure: struct i2c_master_module i2c_master_instance; Globally accessible packet: struct i2c_master_packet wr_packet; struct i2c_master_packet rd_packet; Function for setting up module: void configure_i2c(void) { /* Initialize config structure and software module */ struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); /* Change buffer timeout to something longer */ config_i2c_master.buffer_timeout = 65535; /* Initialize and enable device with config */ while(i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master) != STATUS_OK); } \ i2c_master_enable(&i2c_master_instance); Callback function for write complete: void i2c_write_complete_callback( struct i2c_master_module *const module) { /* Initiate new packet read */ i2c_master_read_packet_job(&i2c_master_instance,&rd_packet); } Function for setting up the callback functionality of the driver: void configure_i2c_callbacks(void) { /* Register callback function. */ i2c_master_register_callback(&i2c_master_instance, i2c_write_complete_callback, I2C_MASTER_CALLBACK_WRITE_COMPLETE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 200 i2c_master_enable_callback(&i2c_master_instance, I2C_MASTER_CALLBACK_WRITE_COMPLETE); } Add to user application main(): /* Configure device and enable. */ configure_i2c(); /* Configure callbacks and enable. */ configure_i2c_callbacks(); Workflow 1. Configure and enable module. configure_i2c(); a. Create and initialize configuration structure. struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); b. Change settings in the configuration. config_i2c_master.buffer_timeout = 65535; c. Initialize the module with the set configurations. while(i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master) != STATUS_OK); d. \ Enable the module. i2c_master_enable(&i2c_master_instance); 2. Configure callback functionality. configure_i2c_callbacks(); a. Register write complete callback. i2c_master_register_callback(&i2c_master_instance, i2c_write_complete_callback, I2C_MASTER_CALLBACK_WRITE_COMPLETE); b. Enable write complete callback. i2c_master_enable_callback(&i2c_master_instance, I2C_MASTER_CALLBACK_WRITE_COMPLETE); 3. Create a packet to send to slave. wr_packet.address = SLAVE_ADDRESS; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 201 wr_packet.data_length = DATA_LENGTH; wr_packet.data = wr_buffer; 9.8.2.3 Implementation Code Add to user application main(): while (true) { /* Infinite loop */ if (!port_pin_get_input_level(BUTTON_0_PIN)) { /* Send every other packet with reversed data */ if (wr_packet.data[0] == 0x00) { wr_packet.data = &wr_buffer_reversed[0]; } else { wr_packet.data = &wr_buffer[0]; } i2c_master_write_packet_job(&i2c_master_instance, &wr_packet); } } Workflow 1. Write packet to slave. wr_packet.address = SLAVE_ADDRESS; wr_packet.data_length = DATA_LENGTH; wr_packet.data = wr_buffer; 2. Infinite while loop, while waiting for interaction with slave. while (true) { /* Infinite loop */ if (!port_pin_get_input_level(BUTTON_0_PIN)) { /* Send every other packet with reversed data */ if (wr_packet.data[0] == 0x00) { wr_packet.data = &wr_buffer_reversed[0]; } else { wr_packet.data = &wr_buffer[0]; } i2c_master_write_packet_job(&i2c_master_instance, &wr_packet); } } 9.8.2.4 Callback Each time a packet is sent, the callback function will be called. Workflow ● Write complete callback: 1. Send every other packet in reversed order. if (wr_packet.data[0] == 0x00) { wr_packet.data = &wr_buffer_reversed[0]; } else { wr_packet.data = &wr_buffer[0]; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 202 } 2. Write new packet to slave. wr_packet.address = SLAVE_ADDRESS; wr_packet.data_length = DATA_LENGTH; wr_packet.data = wr_buffer; 9.8.3 Quick Start Guide for Using DMA with SERCOM I2C Master The supported board list: ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAML21 Xplained Pro 2 In this use case, the I C will used and set up as follows: 9.8.3.1 ● Master mode ● 100KHz operation speed ● Not operational in standby ● 10000 packet timeout value ● 65535 unknown bus state timeout value Prerequisites 2 The device must be connected to an I C slave. 9.8.3.2 Setup Code The following must be added to the user application: ● A sample buffer to send, number of entries to send and address of slave: #define DATA_LENGTH 10 static uint8_t buffer[DATA_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, }; #define SLAVE_ADDRESS 0x12 Number of times to try to send packet if it fails: #define TIMEOUT 1000 ● Globally accessible module structure: struct i2c_master_module i2c_master_instance; ● Function for setting up the module: static void configure_i2c_master(void) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 203 { /* Initialize config structure and software module. */ struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); /* Change buffer timeout to something longer. */ config_i2c_master.buffer_timeout = 10000; /* Initialize and enable device with config. */ i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master); } ● i2c_master_enable(&i2c_master_instance); Globally accessible DMA module structure: struct dma_resource example_resource; ● Globally transfer done flag: static volatile bool transfer_is_done = false; ● Globally accessible DMA transfer descriptor: COMPILER_ALIGNED(16) DmacDescriptor example_descriptor; ● Function for transfer done callback: static void transfer_done( const struct dma_resource* const resource ) { UNUSED(resource); } ● transfer_is_done = true; Function for setting up the DMA resource: static void configure_dma_resource(struct dma_resource *resource) { struct dma_resource_config config; dma_get_config_defaults(&config); config.peripheral_trigger = SERCOM2_DMAC_ID_TX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } ● dma_allocate(resource, &config); Function for setting up the DMA transfer descriptor: static void setup_dma_descriptor(DmacDescriptor *descriptor) { struct dma_descriptor_config descriptor_config; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 204 dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; descriptor_config.dst_increment_enable = false; descriptor_config.block_transfer_count = DATA_LENGTH; descriptor_config.source_address = (uint32_t)buffer + DATA_LENGTH; descriptor_config.destination_address = (uint32_t)(&i2c_master_instance.hw->I2CM.DATA.reg); } ● dma_descriptor_create(descriptor, &descriptor_config); Add to user application main(): configure_i2c_master(); configure_dma_resource(&example_resource); setup_dma_descriptor(&example_descriptor); dma_add_descriptor(&example_resource, &example_descriptor); dma_register_callback(&example_resource, transfer_done, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&example_resource, DMA_CALLBACK_TRANSFER_DONE); Workflow Configure and enable SERCOM: configure_i2c_master(); 1. Create and initialize configuration structure. struct i2c_master_config config_i2c_master; i2c_master_get_config_defaults(&config_i2c_master); 2. Change settings in the configuration. config_i2c_master.buffer_timeout = 10000; 3. Initialize the module with the set configurations. i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master); 4. Enable the module. i2c_master_enable(&i2c_master_instance); Configure DMA 1. Create a DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config config; 2. Initialize the DMA resource configuration struct with the module's default values. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 205 dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM TX trigger causes a transaction transfer in this example. config.peripheral_trigger = SERCOM2_DMAC_ID_TX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; 4. Allocate a DMA resource with the configurations. dma_allocate(resource, &config); 5. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; 6. Initialize the DMA transfer descriptor configuration struct with the module's default values. dma_descriptor_get_config_defaults(&descriptor_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 7. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; descriptor_config.dst_increment_enable = false; descriptor_config.block_transfer_count = DATA_LENGTH; descriptor_config.source_address = (uint32_t)buffer + DATA_LENGTH; descriptor_config.destination_address = (uint32_t)(&i2c_master_instance.hw->I2CM.DATA.reg); 8. Create the DMA transfer descriptor. dma_descriptor_create(descriptor, &descriptor_config); 9.8.3.3 Implementation Code Add to user application main(): dma_start_transfer_job(&example_resource); i2c_master_dma_set_transfer(&i2c_master_instance, SLAVE_ADDRESS, DATA_LENGTH, I2C_TRANSFER_WRITE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 206 while (!transfer_is_done) { /* Wait for transfer done */ } while (true) { } Workflow 1. Start the DMA transfer job. dma_start_transfer_job(&example_resource); 2. Set the auto address length and enable flag. i2c_master_dma_set_transfer(&i2c_master_instance, SLAVE_ADDRESS, DATA_LENGTH, I2C_TRANSFER_WRITE); 3. Waiting for transfer complete. while (!transfer_is_done) { /* Wait for transfer done */ } 4. Enter an infinite loop once transfer complete. while (true) { } 9.8.4 Quick Start Guide for SERCOM I2C Slave - Basic 2 In this use case, the I C will used and set up as follows: 9.8.4.1 ● Slave mode ● 100KHz operation speed ● Not operational in standby ● 10000 packet timeout value Prerequisites 2 The device must be connected to an I C master. 9.8.4.2 Setup Code The following must be added to the user application: A sample buffer to write from, a sample buffer to read to and length of buffers: #define DATA_LENGTH 10 uint8_t write_buffer[DATA_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 207 }; uint8_t read_buffer[DATA_LENGTH]; Address to respond to: #define SLAVE_ADDRESS 0x12 Globally accessible module structure: struct i2c_slave_module i2c_slave_instance; Function for setting up the module: void configure_i2c_slave(void) { /* Create and initialize config_i2c_slave structure */ struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); /* Change address and address_mode */ config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; config_i2c_slave.buffer_timeout = 1000; /* Initialize and enable device with config_i2c_slave */ i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); i2c_slave_enable(&i2c_slave_instance); } Add to user application main(): configure_i2c_slave(); enum i2c_slave_direction dir; struct i2c_slave_packet packet = { .data_length = DATA_LENGTH, .data = write_buffer, }; Workflow 1. Configure and enable module. configure_i2c_slave(); a. Create and initialize configuration structure. struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); b. Change address and address mode settings in the configuration. config_i2c_slave.address config_i2c_slave.address_mode = SLAVE_ADDRESS; = I2C_SLAVE_ADDRESS_MODE_MASK; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 208 config_i2c_slave.buffer_timeout = 1000; c. Initialize the module with the set configurations. i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); d. Enable the module. i2c_slave_enable(&i2c_slave_instance); 2. Create variable to hold transfer direction. enum i2c_slave_direction dir; 3. Create packet variable to transfer. struct i2c_slave_packet packet = { .data_length = DATA_LENGTH, .data = write_buffer, }; 9.8.4.3 Implementation Code Add to user application main(): while (true) { /* Wait for direction from master */ dir = i2c_slave_get_direction_wait(&i2c_slave_instance); } /* Transfer packet in direction requested by master */ if (dir == I2C_SLAVE_DIRECTION_READ) { packet.data = read_buffer; i2c_slave_read_packet_wait(&i2c_slave_instance, &packet); } else if (dir == I2C_SLAVE_DIRECTION_WRITE) { packet.data = write_buffer; i2c_slave_write_packet_wait(&i2c_slave_instance, &packet); } Workflow 1. Wait for start condition from master and get transfer direction. dir = i2c_slave_get_direction_wait(&i2c_slave_instance); 2. Depending on transfer direction, set up buffer to read to or write from, and write or read from master. if (dir == I2C_SLAVE_DIRECTION_READ) { packet.data = read_buffer; i2c_slave_read_packet_wait(&i2c_slave_instance, &packet); } else if (dir == I2C_SLAVE_DIRECTION_WRITE) { packet.data = write_buffer; i2c_slave_write_packet_wait(&i2c_slave_instance, &packet); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 209 } 9.8.5 Quick Start Guide for SERCOM I2C Slave - Callback 2 In this use case, the I C will used and set up as follows: 9.8.5.1 ● Slave mode ● 100KHz operation speed ● Not operational in standby ● 10000 packet timeout value Prerequisites 2 The device must be connected to an I C master. 9.8.5.2 Setup Code The following must be added to the user application: A sample buffer to write from, a sample buffer to read to and length of buffers: #define DATA_LENGTH 10 static uint8_t write_buffer[DATA_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, }; static uint8_t read_buffer [DATA_LENGTH]; Address to respond to: #define SLAVE_ADDRESS 0x12 Globally accessible module structure: struct i2c_slave_module i2c_slave_instance; Globally accessible packet: static struct i2c_slave_packet packet; Function for setting up the module: void configure_i2c_slave(void) { /* Initialize config structure and module instance. */ struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); /* Change address and address_mode. */ config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; /* Initialize and enable device with config. */ i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); } i2c_slave_enable(&i2c_slave_instance); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 210 Callback function for read request from a master: void i2c_read_request_callback( struct i2c_slave_module *const module) { /* Init i2c packet. */ packet.data_length = DATA_LENGTH; packet.data = write_buffer; /* Write buffer to master */ i2c_slave_write_packet_job(module, &packet); } Callback function for write request from a master: void i2c_write_request_callback( struct i2c_slave_module *const module) { /* Init i2c packet. */ packet.data_length = DATA_LENGTH; packet.data = read_buffer; /* Read buffer from master */ if (i2c_slave_read_packet_job(module, &packet) != STATUS_OK) { } } Function for setting up the callback functionality of the driver: void configure_i2c_slave_callbacks(void) { /* Register and enable callback functions */ i2c_slave_register_callback(&i2c_slave_instance, i2c_read_request_callback, I2C_SLAVE_CALLBACK_READ_REQUEST); i2c_slave_enable_callback(&i2c_slave_instance, I2C_SLAVE_CALLBACK_READ_REQUEST); i2c_slave_register_callback(&i2c_slave_instance, i2c_write_request_callback, I2C_SLAVE_CALLBACK_WRITE_REQUEST); i2c_slave_enable_callback(&i2c_slave_instance, I2C_SLAVE_CALLBACK_WRITE_REQUEST); } Add to user application main(): /* Configure device and enable. */ configure_i2c_slave(); configure_i2c_slave_callbacks(); Workflow 1. Configure and enable module. configure_i2c_slave(); a. Create and initialize configuration structure. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 211 struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); b. Change address and address mode settings in the configuration. config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; c. Initialize the module with the set configurations. i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); d. Enable the module. i2c_slave_enable(&i2c_slave_instance); 2. Register and enable callback functions. configure_i2c_slave_callbacks(); a. Register and enable callbacks for read and write requests from master. i2c_slave_register_callback(&i2c_slave_instance, i2c_read_request_callback, I2C_SLAVE_CALLBACK_READ_REQUEST); i2c_slave_enable_callback(&i2c_slave_instance, I2C_SLAVE_CALLBACK_READ_REQUEST); i2c_slave_register_callback(&i2c_slave_instance, i2c_write_request_callback, I2C_SLAVE_CALLBACK_WRITE_REQUEST); i2c_slave_enable_callback(&i2c_slave_instance, I2C_SLAVE_CALLBACK_WRITE_REQUEST); 9.8.5.3 Implementation Code Add to user application main(): while (true) { /* Infinite loop while waiting for I2C master interaction */ } Workflow 1. Infinite while loop, while waiting for interaction from master. while (true) { /* Infinite loop while waiting for I2C master interaction */ } 9.8.5.4 Callback When an address packet is received, one of the callback functions will be called, depending on the DIR bit in the received packet. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 212 Workflow ● Read request callback: 1. Length of buffer and buffer to be sent to master is initialized. packet.data_length = DATA_LENGTH; packet.data = write_buffer; 2. Write packet to master. i2c_slave_write_packet_job(module, &packet); ● Write request callback: 1. Length of buffer and buffer to be read from master is initialized. packet.data_length = DATA_LENGTH; packet.data = read_buffer; 2. Read packet from master. if (i2c_slave_read_packet_job(module, &packet) != STATUS_OK) { } 9.8.6 Quick Start Guide for Using DMA with SERCOM I2C Slave The supported board list: ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAML21 Xplained Pro 2 In this use case, the I C will used and set up as follows: 9.8.6.1 ● Slave mode ● 100KHz operation speed ● Not operational in standby ● 65535 unknown bus state timeout value Prerequisites 2 The device must be connected to an I C slave. 9.8.6.2 Setup Code The following must be added to the user application: ● Address to respond to: #define SLAVE_ADDRESS 0x12 ● A sample buffer to send, number of entries to send and address of slave: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 213 #define DATA_LENGTH 10 uint8_t read_buffer[DATA_LENGTH]; ● Globally accessible module structure: struct i2c_slave_module i2c_slave_instance; ● Function for setting up the module: void configure_i2c_slave(void) { /* Create and initialize config_i2c_slave structure */ struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); /* Change address and address_mode */ config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; config_i2c_slave.buffer_timeout = 1000; /* Initialize and enable device with config_i2c_slave */ i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); } ● i2c_slave_enable(&i2c_slave_instance); Globally accessible DMA module structure: struct dma_resource i2c_dma_resource; ● Globally accessible DMA transfer descriptor: COMPILER_ALIGNED(16) DmacDescriptor i2c_dma_descriptor; ● Function for setting up the DMA resource: void configure_dma_resource(struct dma_resource *resource) { struct dma_resource_config config; dma_get_config_defaults(&config); config.peripheral_trigger = SERCOM2_DMAC_ID_RX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } ● dma_allocate(resource, &config); Function for setting up the DMA transfer descriptor: void setup_dma_descriptor(DmacDescriptor *descriptor) { struct dma_descriptor_config descriptor_config; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 214 dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; descriptor_config.src_increment_enable = false; descriptor_config.block_transfer_count = DATA_LENGTH; descriptor_config.destination_address = (uint32_t)read_buffer + DATA_LENGTH; descriptor_config.source_address = (uint32_t)(&i2c_slave_instance.hw->I2CS.DATA.reg); } ● dma_descriptor_create(descriptor, &descriptor_config); Add to user application main(): configure_i2c_slave(); configure_dma_resource(&i2c_dma_resource); setup_dma_descriptor(&i2c_dma_descriptor); dma_add_descriptor(&i2c_dma_resource, &i2c_dma_descriptor); Workflow Configure and enable SERCOM: void configure_i2c_slave(void) { /* Create and initialize config_i2c_slave structure */ struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); /* Change address and address_mode */ config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; config_i2c_slave.buffer_timeout = 1000; /* Initialize and enable device with config_i2c_slave */ i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); } 1. i2c_slave_enable(&i2c_slave_instance); Create and initialize configuration structure. struct i2c_slave_config config_i2c_slave; i2c_slave_get_config_defaults(&config_i2c_slave); 2. Change settings in the configuration. config_i2c_slave.address = SLAVE_ADDRESS; config_i2c_slave.address_mode = I2C_SLAVE_ADDRESS_MODE_MASK; config_i2c_slave.buffer_timeout = 1000; 3. Initialize the module with the set configurations. i2c_slave_init(&i2c_slave_instance, SERCOM2, &config_i2c_slave); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 215 4. Enable the module. i2c_slave_enable(&i2c_slave_instance); Configure DMA 1. Create a DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config config; 2. Initialize the DMA resource configuration struct with the module's default values. dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM RX trigger causes a beat transfer in this example. config.peripheral_trigger = SERCOM2_DMAC_ID_RX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; 4. Allocate a DMA resource with the configurations. dma_allocate(resource, &config); 5. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; 6. Initialize the DMA transfer descriptor configuration struct with the module's default values. dma_descriptor_get_config_defaults(&descriptor_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 7. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; descriptor_config.src_increment_enable = false; descriptor_config.block_transfer_count = DATA_LENGTH; descriptor_config.destination_address = (uint32_t)read_buffer + DATA_LENGTH; descriptor_config.source_address = (uint32_t)(&i2c_slave_instance.hw->I2CS.DATA.reg); 8. Create the DMA transfer descriptor. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 216 dma_descriptor_create(descriptor, &descriptor_config); 9.8.6.3 Implementation Code Add to user application main(): dma_start_transfer_job(&i2c_dma_resource); while (true) { if (i2c_slave_dma_read_interrupt_status(&i2c_slave_instance) & SERCOM_I2CS_INTFLAG_AMATCH) { i2c_slave_dma_write_interrupt_status(&i2c_slave_instance, SERCOM_I2CS_INTFLAG_AMATCH); } } Workflow 1. Start to wait a packet from master. dma_start_transfer_job(&i2c_dma_resource); 2. Once data ready, clear the address match status. while (true) { if (i2c_slave_dma_read_interrupt_status(&i2c_slave_instance) & SERCOM_I2CS_INTFLAG_AMATCH) { i2c_slave_dma_write_interrupt_status(&i2c_slave_instance, SERCOM_I2CS_INTFLAG_AMATCH); } } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 217 10. SAM Non-Volatile Memory Driver (NVM) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of nonvolatile memories within the device, for partitioning, erasing, reading, and writing of data. The following peripherals are used by this module: ● NVM (Non-Volatile Memory) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 10.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 10.2 Module Overview The Non-Volatile Memory (NVM) module provides an interface to the device's Non-Volatile Memory controller, so that memory pages can be written, read, erased and reconfigured in a standardized manner. 10.2.1 Driver Feature Macro Definition Note 10.2.2 Driver Feature Macro Supported devices FEATURE_NVM_RWWEE SAML21 The specific features are only available in the driver when the selected device supports those features. Memory Regions The NVM memory space of the SAM devices is divided into two sections: a Main Array section, and an Auxiliary space section. The Main Array space can be configured to have an (emulated) EEPROM and/or boot loader 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 218 section. The memory layout with the EEPROM and bootloader partitions is shown in Figure 10-1: Memory Regions on page 219. Figure 10-1. Memory Regions E n d o f N VM M e m o r y Re s e r ve d E E P ROM S e c t io n S t a r t o f E E P ROM M e m o r y E n d o f Ap p lic a t io n M e m o r y Ap p lic a t io n S e c t io n S t a r t o f Ap p lic a t io n M e m o r y E n d o f Bo o t lo a d e r M e m o r y BOOT S e c t io n S t a r t o f N VM M e m o r y The Main Array is divided into rows and pages, where each row contains four pages. The size of each page may vary from 8-1024 bytes dependent of the device. Device specific parameters such as the page size and total number of pages in the NVM memory space are available via the nvm_get_parameters() function. A NVM page number and address can be computed via the following equations: (10.1) (10.2) Figure 10-2: Memory Regions on page 219 shows an example of the memory page and address values associated with logical row 7 of the NVM memory space. Figure 10-2. Memory Regions Ro w 0 x0 7P a g e 0 x1 FP a g e 0 x1 EP a g e 0 x1 DP a g e 0 x1 C Ad d r e s s 0 x7 C0 0 x7 8 0 0 x7 4 0 0 x7 0 0 10.2.3 Region Lock Bits As mentioned in Memory Regions, the main block of the NVM memory is divided into a number of individually addressable pages. These pages are grouped into 16 equal sized regions, where each region can be locked AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 219 separately issuing an NVM_COMMAND_LOCK_REGION on page 230 command or by writing the LOCK bits in the User Row. Rows reserved for the EEPROM section are not affected by the lock bits or commands. Note By using the NVM_COMMAND_LOCK_REGION on page 230 or NVM_COMMAND_UNLOCK_REGION on page 230 commands the settings will remain in effect until the next device reset. By changing the default lock setting for the regions, the auxiliary space must to be written, however the adjusted configuration will not take effect until the next device reset. If the Security Bit is set, the auxiliary space cannot be written to. Clearing of the security bit can only be performed by a full chip erase. 10.2.4 Read/Write Reading from the NVM memory can be performed using direct addressing into the NVM memory space, or by calling the nvm_read_buffer() function. Writing to the NVM memory must be performed by the nvm_write_buffer() function - additionally, a manual page program command must be issued if the NVM controller is configured in manual page writing mode, or a buffer of data less than a full page is passed to the buffer write function. Before a page can be updated, the associated NVM memory row must be erased first via the nvm_erase_row() function. Writing to a non-erased page will result in corrupt data being stored in the NVM memory space. 10.3 Special Considerations 10.3.1 Page Erasure The granularity of an erase is per row, while the granularity of a write is per page. Thus, if the user application is modifying only one page of a row, the remaining pages in the row must be buffered and the row erased, as an erase is mandatory before writing to a page. 10.3.2 Clocks The user must ensure that the driver is configured with a proper number of wait states when the CPU is running at high frequencies. 10.3.3 Security Bit The User Row in the Auxiliary Space Cannot be read or written when the Security Bit is set. The Security Bit can be set by using passing NVM_COMMAND_SET_SECURITY_BIT on page 230 to the nvm_execute_command() function, or it will be set if one tries to access a locked region. See Region Lock Bits. The Security Bit can only be cleared by performing a chip erase. 10.4 Extra Information For extra information, see Extra Information for NVM Driver. This includes: 10.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for NVM Driver. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 220 10.6 API Overview 10.6.1 Structure Definitions 10.6.1.1 Struct nvm_config Configuration structure for the NVM controller within the device. Table 10-1. Members Type Name Description enum nvm_cache_readmode cache_readmode Select the mode for how the cache will pre-fetch data from the flash. bool disable_cache Setting this to true will disable the pre-fetch cache in front of the nvm controller. bool manual_page_write Manual write mode; if enabled, pages loaded into the NVM buffer will not be written until a separate write command is issued. If disabled, writing to the last byte in the NVM page buffer will trigger an 1 automatic write. enum nvm_sleep_power_mode sleep_power_mode Power reduction mode during device sleep. uint8_t wait_states Number of wait states to insert when reading from flash, to prevent invalid data from being read at high clock frequencies. Notes: 1 If a partial page is to be written, a manual write command must be executed in either mode. 10.6.1.2 Struct nvm_fusebits This structure contain the layout of the first 64 bits of the user row which contain the fuse settings. Table 10-2. Members Type Name Description enum nvm_bod33_action bod33_action BOD33 Action at power on. bool bod33_enable BOD33 Enable at power on. uint8_t bod33_level BOD33 Threshold level at power on. enum nvm_bootloader_size bootloader_size Bootloader size. enum nvm_eeprom_emulator_size eeprom_size EEPROM emulation area size. uint16_t lockbits NVM Lock bits. bool wdt_always_on WDT Always-on at power on. enum nvm_wdt_early_warning_offset wdt_early_warning_offset WDT Early warning interrupt time offset at power on. bool wdt_enable WDT Enable at power on. uint8_t wdt_timeout_period WDT Period at power on. bool wdt_window_mode_enable_at_poweron WDT Window mode enabled at power on. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 221 Type Name Description enum nvm_wdt_window_timeout wdt_window_timeout WDT Window mode time-out at power on. 10.6.1.3 Struct nvm_parameters Structure containing the memory layout parameters of the NVM module. Table 10-3. Members 10.6.2 Type Name Description uint32_t bootloader_number_of_pages Size of the Bootloader memory section configured in the NVM auxiliary memory space. uint32_t eeprom_number_of_pages Size of the emulated EEPROM memory section configured in the NVM auxiliary memory space. uint16_t nvm_number_of_pages Number of pages in the main array. uint8_t page_size Number of bytes per page. Function Definitions 10.6.2.1 Configuration and Initialization Function nvm_get_config_defaults() Initializes an NVM controller configuration structure to defaults. void nvm_get_config_defaults( struct nvm_config *const config) Initializes a given NVM controller configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Power reduction mode enabled after sleep until first NVM access ● Automatic page commit when full pages are written to ● Number of FLASH wait states left unchanged Table 10-4. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function nvm_set_config() Sets the up the NVM hardware module based on the configuration. enum status_code nvm_set_config( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 222 const struct nvm_config *const config) Writes a given configuration of a NVM controller configuration to the hardware module, and initializes the internal device struct. Table 10-5. Parameters Data direction Parameter name Description [in] config Configuration settings for the NVM controller Note The security bit must be cleared in order successfully use this function. This can only be done by a chip erase. Returns Status of the configuration procedure. Table 10-6. Return Values Return value Description STATUS_OK If the initialization was a success STATUS_BUSY If the module was busy when the operation was attempted STATUS_ERR_IO If the security bit has been set, preventing the EEPROM and/or auxiliary space configuration from being altered Function nvm_is_ready() Checks if the NVM controller is ready to accept a new command. bool nvm_is_ready(void) Checks the NVM controller to determine if it is currently busy execution an operation, or ready for a new command. Returns Busy state of the NVM controller. Table 10-7. Return Values Return value Description true If the hardware module is ready for a new command false If the hardware module is busy executing a command 10.6.2.2 NVM Access Management Function nvm_get_parameters() Reads the parameters of the NVM controller. void nvm_get_parameters( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 223 struct nvm_parameters *const parameters) Retrieves the page size, number of pages and other configuration settings of the NVM region. Table 10-8. Parameters Data direction Parameter name Description [out] parameters Parameter structure, which holds page size and number of pages in the NVM memory Function nvm_write_buffer() Writes a number of bytes to a page in the NVM memory region. enum status_code nvm_write_buffer( const uint32_t destination_address, const uint8_t * buffer, uint16_t length) Writes from a buffer to a given page address in the NVM memory. Table 10-9. Parameters Data direction Parameter name Description [in] destination_address Destination page address to write to [in] buffer Pointer to buffer where the data to write is stored [in] length Number of bytes in the page to write Note If writing to a page that has previously been written to, the page's row should be erased (via nvm_erase_row()) before attempting to write new data to the page. Returns Status of the attempt to write a page. Table 10-10. Return Values Return value Description STATUS_OK Requested NVM memory page was successfully read STATUS_BUSY NVM controller was busy when the operation was attempted STATUS_ERR_BAD_ADDRESS The requested address was outside the acceptable range of the NVM memory region or not aligned to the start of a page STATUS_ERR_INVALID_ARG The supplied write length was invalid Function nvm_read_buffer() Reads a number of bytes from a page in the NVM memory region. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 224 enum status_code nvm_read_buffer( const uint32_t source_address, uint8_t *const buffer, uint16_t length) Reads a given number of bytes from a given page address in the NVM memory space into a buffer. Table 10-11. Parameters Data direction Parameter name Description [in] source_address Source page address to read from [out] buffer Pointer to a buffer where the content of the read page will be stored [in] length Number of bytes in the page to read Returns Status of the page read attempt. Table 10-12. Return Values Return value Description STATUS_OK Requested NVM memory page was successfully read STATUS_BUSY NVM controller was busy when the operation was attempted STATUS_ERR_BAD_ADDRESS The requested address was outside the acceptable range of the NVM memory region or not aligned to the start of a page STATUS_ERR_INVALID_ARG The supplied read length was invalid Function nvm_update_buffer() Updates an arbitrary section of a page with new data. enum status_code nvm_update_buffer( const uint32_t destination_address, uint8_t *const buffer, uint16_t offset, uint16_t length) Writes from a buffer to a given page in the NVM memory, retaining any unmodified data already stored in the page. Warning This routine is unsafe if data integrity is critical; a system reset during the update process will result in up to one row of data being lost. If corruption must be avoided in all circumstances (including power loss or system reset) this function should not be used. Table 10-13. Parameters Data direction Parameter name Description [in] destination_address Destination page address to write to AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 225 Data direction Parameter name Description [in] buffer Pointer to buffer where the data to write is stored [in] offset Number of bytes to offset the data write in the page [in] length Number of bytes in the page to update Returns Status of the attempt to update a page. Table 10-14. Return Values Return value Description STATUS_OK Requested NVM memory page was successfully read STATUS_BUSY NVM controller was busy when the operation was attempted STATUS_ERR_BAD_ADDRESS The requested address was outside the acceptable range of the NVM memory region STATUS_ERR_INVALID_ARG The supplied length and offset was invalid Function nvm_erase_row() Erases a row in the NVM memory space. enum status_code nvm_erase_row( const uint32_t row_address) Erases a given row in the NVM memory region. Table 10-15. Parameters Returns Data direction Parameter name Description [in] row_address Address of the row to erase Status of the NVM row erase attempt. Table 10-16. Return Values Return value Description STATUS_OK Requested NVM memory row was successfully erased STATUS_BUSY NVM controller was busy when the operation was attempted STATUS_ERR_BAD_ADDRESS The requested row address was outside the acceptable range of the NVM memory region or not aligned to the start of a row Function nvm_execute_command() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 226 Executes a command on the NVM controller. enum status_code nvm_execute_command( const enum nvm_command command, const uint32_t address, const uint32_t parameter) Executes an asynchronous command on the NVM controller, to perform a requested action such as a NVM page read or write operation. Note The function will return before the execution of the given command is completed. Table 10-17. Parameters Data direction Parameter name Description [in] command Command to issue to the NVM controller [in] address Address to pass to the NVM controller in NVM memory space [in] parameter Parameter to pass to the NVM controller, not used for this driver Returns Status of the attempt to execute a command. Table 10-18. Return Values Return value Description STATUS_OK If the command was accepted and execution is now in progress STATUS_BUSY If the NVM controller was already busy executing a command when the new command was issued STATUS_ERR_IO If the command was invalid due to memory or security locking STATUS_ERR_INVALID_ARG If the given command was invalid or unsupported STATUS_ERR_BAD_ADDRESS If the given address was invalid Function nvm_get_fuses() Get fuses from user row. enum status_code nvm_get_fuses( struct nvm_fusebits * fusebits) Read out the fuse settings from the user row. Table 10-19. Parameters Data direction Parameter name Description [in] fusebits Pointer to a 64-bit wide memory buffer of type struct nvm_fusebits AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 227 Returns Status of read fuses attempt. Table 10-20. Return Values Return value Description STATUS_OK This function will always return STATUS_OK Function nvm_is_page_locked() Checks whether the page region is locked. bool nvm_is_page_locked( uint16_t page_number) Extracts the region to which the given page belongs and checks whether that region is locked. Table 10-21. Parameters Data direction Parameter name Description [in] page_number Page number to be checked Returns Page lock status. Table 10-22. Return Values Return value Description true Page is locked false Page is not locked Function nvm_get_error() Retrieves the error code of the last issued NVM operation. enum nvm_error nvm_get_error(void) Retrieves the error code from the last executed NVM operation. Once retrieved, any error state flags in the controller are cleared. Note The nvm_is_ready() function is an exception. Thus, errors retrieved after running this function should be valid for the function executed before nvm_is_ready(). Returns Error caused by the last NVM operation. Table 10-23. Return Values Return value Description NVM_ERROR_NONE No error occurred in the last NVM operation AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 228 10.6.3 Return value Description NVM_ERROR_LOCK The last NVM operation attempted to access a locked region NVM_ERROR_PROG An invalid NVM command was issued Enumeration Definitions 10.6.3.1 Enum nvm_bod33_action What action should be triggered when BOD33 is detected. Table 10-24. Members Enum value Description NVM_BOD33_ACTION_NONE No action. NVM_BOD33_ACTION_RESET The BOD33 generates a reset. NVM_BOD33_ACTION_INTERRUPT The BOD33 generates an interrupt. 10.6.3.2 Enum nvm_bootloader_size Available bootloader protection sizes in kilobytes. Table 10-25. Members Enum value Description NVM_BOOTLOADER_SIZE_128 Boot Loader Size is 32768 Bytes. NVM_BOOTLOADER_SIZE_64 Boot Loader Size is 16384 Bytes. NVM_BOOTLOADER_SIZE_32 Boot Loader Size is 8192 Bytes. NVM_BOOTLOADER_SIZE_16 Boot Loader Size is 4096 Bytes. NVM_BOOTLOADER_SIZE_8 Boot Loader Size is 2048 Bytes. NVM_BOOTLOADER_SIZE_4 Boot Loader Size is 1024 Bytes. NVM_BOOTLOADER_SIZE_2 Boot Loader Size is 512 Bytes. NVM_BOOTLOADER_SIZE_0 Boot Loader Size is 0 Bytes. 10.6.3.3 Enum nvm_cache_readmode Control how the NVM cache prefetch data from flash. Table 10-26. Members Enum value Description NVM_CACHE_READMODE_NO_MISS_PENALTY The NVM Controller (cache system) does not insert wait states on a cache miss. Gives the best system performance. NVM_CACHE_READMODE_LOW_POWER Reduces power consumption of the cache system, but inserts a wait state each time there is a cache miss. NVM_CACHE_READMODE_DETERMINISTIC The cache system ensures that a cache hit or miss takes the same amount of time, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 229 Enum value Description determined by the number of programmed flash wait states. 10.6.3.4 Enum nvm_command Table 10-27. Members Enum value Description NVM_COMMAND_ERASE_ROW Erases the addressed memory row. NVM_COMMAND_WRITE_PAGE Write the contents of the page buffer to the addressed memory page. NVM_COMMAND_ERASE_AUX_ROW Erases the addressed auxiliary memory row. Note NVM_COMMAND_WRITE_AUX_ROW This command can only be given when the security bit is not set. Write the contents of the page buffer to the addressed auxiliary memory row. Note This command can only be given when the security bit is not set. NVM_COMMAND_LOCK_REGION Locks the addressed memory region, preventing further modifications until the region is unlocked or the device is erased. NVM_COMMAND_UNLOCK_REGION Unlocks the addressed memory region, allowing the region contents to be modified. NVM_COMMAND_PAGE_BUFFER_CLEAR Clears the page buffer of the NVM controller, resetting the contents to all zero values. NVM_COMMAND_SET_SECURITY_BIT Sets the device security bit, disallowing the changing of lock bits and auxiliary row data until a chip erase has been performed. NVM_COMMAND_ENTER_LOW_POWER_MODE Enter power reduction mode in the NVM controller to reduce the power consumption of the system. NVM_COMMAND_EXIT_LOW_POWER_MODE Exit power reduction mode in the NVM controller to allow other NVM commands to be issued. 10.6.3.5 Enum nvm_eeprom_emulator_size Available space in flash dedicated for EEPROM emulator in bytes. Table 10-28. Members Enum value Description NVM_EEPROM_EMULATOR_SIZE_16384 EEPROM Size for EEPROM emulation is 16384 bytes. NVM_EEPROM_EMULATOR_SIZE_8192 EEPROM Size for EEPROM emulation is 8192 bytes. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 230 Enum value Description NVM_EEPROM_EMULATOR_SIZE_4096 EEPROM Size for EEPROM emulation is 4096 bytes. NVM_EEPROM_EMULATOR_SIZE_2048 EEPROM Size for EEPROM emulation is 2048 bytes. NVM_EEPROM_EMULATOR_SIZE_1024 EEPROM Size for EEPROM emulation is 1024 bytes. NVM_EEPROM_EMULATOR_SIZE_512 EEPROM Size for EEPROM emulation is 512 bytes. NVM_EEPROM_EMULATOR_SIZE_256 EEPROM Size for EEPROM emulation is 256 bytes. NVM_EEPROM_EMULATOR_SIZE_0 EEPROM Size for EEPROM emulation is 0 bytes. 10.6.3.6 Enum nvm_error Define NVM features set according to different device family Possible NVM controller error codes, which can be returned by the NVM controller after a command is issued. Table 10-29. Members Enum value Description NVM_ERROR_NONE No errors. NVM_ERROR_LOCK Lock error, a locked region was attempted accessed. NVM_ERROR_PROG Program error, invalid command was executed. 10.6.3.7 Enum nvm_sleep_power_mode Power reduction modes of the NVM controller, to conserve power while the device is in sleep. Table 10-30. Members Enum value Description NVM_SLEEP_POWER_MODE_WAKEONACCESS NVM controller exits low power mode on first access after sleep. NVM_SLEEP_POWER_MODE_WAKEUPINSTANT NVM controller exits low power mode when the device exits sleep mode. NVM_SLEEP_POWER_MODE_ALWAYS_AWAKE Power reduction mode in the NVM controller disabled. 10.6.3.8 Enum nvm_wdt_early_warning_offset This setting determine how many GCLK_WDT cycles before a watchdog time-out period an early warning interrupt should be triggered. Table 10-31. Members Enum value Description NVM_WDT_EARLY_WARNING_OFFSET_8 8 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_16 16 clock cycles. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 231 Enum value Description NVM_WDT_EARLY_WARNING_OFFSET_32 32 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_64 64 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_128 128 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_256 256 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_512 512 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_1024 1024 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_2048 2048 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_4096 4096 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_8192 8192 clock cycles. NVM_WDT_EARLY_WARNING_OFFSET_16384 16384 clock cycles. 10.6.3.9 Enum nvm_wdt_window_timeout Window mode time-out period in clock cycles. Table 10-32. Members Enum value Description NVM_WDT_WINDOW_TIMEOUT_PERIOD_8 8 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_16 16 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_32 32 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_64 64 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_128 128 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_256 256 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_512 512 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_1024 1024 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_2048 2048 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_4096 4096 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_8192 8192 clock cycles. NVM_WDT_WINDOW_TIMEOUT_PERIOD_16384 16384 clock cycles. 10.7 Extra Information for NVM Driver 10.7.1 Acronyms The table below presents the acronyms used in this module: 10.7.2 Acronym Description NVM Non-Volatile Memory EEPROM Electrically Erasable Programmable Read-Only Memory Dependencies This driver has the following dependencies: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 232 ● 10.7.3 None Errata There are no errata related to this driver. 10.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAML21. Added support for SAMD21, removed BOD12 reference, removed nvm_set_fuses() API Added functions to read/write fuse settings Added support for nvm cache configuration Updated initialization function to also enable the digital interface clock to the module if it is disabled Initial Release 10.8 Examples for NVM Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Non-Volatile Memory Driver (NVM). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● 10.8.1 Quick Start Guide for NVM - Basic Quick Start Guide for NVM - Basic In this use case, the NVM module is configured for: ● Power reduction mode enabled after sleep until first NVM access ● Automatic page write commands issued to commit data as pages are written to the internal buffer ● Zero wait states when reading FLASH memory ● No memory space for the EEPROM ● No protected bootloader section This use case sets up the NVM controller to write a page of data to flash, and the read it back into the same buffer. 10.8.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_nvm(void) { struct nvm_config config_nvm; nvm_get_config_defaults(&config_nvm); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 233 } nvm_set_config(&config_nvm); Add to user application initialization (typically the start of main()): configure_nvm(); Workflow 1. Create an NVM module configuration struct, which can be filled out to adjust the configuration of the NVM controller. struct nvm_config config_nvm; 2. Initialize the NVM configuration struct with the module's default values. nvm_get_config_defaults(&config_nvm); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Configure NVM controller with the created configuration struct settings. nvm_set_config(&config_nvm); 10.8.1.2 Use Case Code Copy-paste the following code to your user application: uint8_t page_buffer[NVMCTRL_PAGE_SIZE]; for (uint32_t i = 0; i < NVMCTRL_PAGE_SIZE; i++) { page_buffer[i] = i; } enum status_code error_code; do { error_code = nvm_erase_row( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE); } while (error_code == STATUS_BUSY); do { error_code = nvm_write_buffer( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE, page_buffer, NVMCTRL_PAGE_SIZE); } while (error_code == STATUS_BUSY); do { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 234 error_code = nvm_read_buffer( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE, page_buffer, NVMCTRL_PAGE_SIZE); } while (error_code == STATUS_BUSY); Workflow 1. Set up a buffer one NVM page in size to hold data to read or write into NVM memory. uint8_t page_buffer[NVMCTRL_PAGE_SIZE]; 2. Fill the buffer with a pattern of data. for (uint32_t i = 0; i < NVMCTRL_PAGE_SIZE; i++) { page_buffer[i] = i; } 3. Create a variable to hold the error status from the called NVM functions. enum status_code error_code; 4. Erase a page of NVM data. As the NVM could be busy initializing or completing a previous operation, a loop is used to retry the command while the NVM controller is busy. do { error_code = nvm_erase_row( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE); } while (error_code == STATUS_BUSY); Note This must be performed before writing new data into a NVM page. 5. Write the buffer of data to the previously erased page of the NVM. do { error_code = nvm_write_buffer( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE, page_buffer, NVMCTRL_PAGE_SIZE); } while (error_code == STATUS_BUSY); Note The new data will be written to NVM memory automatically, as the NVM controller is configured in automatic page write mode. 6. Read back the written page of page from the NVM into the buffer. do { error_code = nvm_read_buffer( 100 * NVMCTRL_ROW_PAGES * NVMCTRL_PAGE_SIZE, page_buffer, NVMCTRL_PAGE_SIZE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 235 } while (error_code == STATUS_BUSY); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 236 11. SAM Peripheral Access Controller Driver (PAC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the locking and unlocking of peripheral registers within the device. When a peripheral is locked, accidental writes to the peripheral will be blocked and a CPU exception will be raised. The following peripherals are used by this module: ● PAC (Peripheral Access Controller) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 11.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 11.2 Module Overview The SAM devices are fitted with a Peripheral Access Controller (PAC) that can be used to lock and unlock write access to a peripheral's registers (see Non-Writable Registers). Locking a peripheral minimizes the risk of unintended configuration changes to a peripheral as a consequence of Run-away Code or use of a Faulty Module Pointer. Physically, the PAC restricts write access through the AHB bus to registers used by the peripheral, making the register non-writable. PAC locking of modules should be implemented in configuration critical applications where avoiding unintended peripheral configuration changes are to be regarded in the highest of priorities. All interrupt must be disabled while a peripheral is unlocked to make sure correct lock/unlock scheme is upheld. 11.2.1 Locking Scheme The module has a built in safety feature requiring that an already locked peripheral is not relocked, and that already unlocked peripherals are not unlocked again. Attempting to unlock and already unlocked peripheral, or attempting to lock a peripheral that is currently locked will generate a CPU exception. This implies that the implementer must keep strict control over the peripheral's lock-state before modifying them. With this added safety, the probability 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 237 of stopping run-away code increases as the program pointer can be caught inside the exception handler, and necessary countermeasures can be initiated. The implementer should also consider using sanity checks after an unlock has been performed to further increase the security. 11.2.2 Recommended Implementation A recommended implementation of the PAC can be seen in Figure 11-1: Recommended Implementation on page 238. Figure 11-1. Recommended Implementation In it ia liza t io n a n d c o d e In it ia lize P e r ip h e r a l Lo c k p e r ip h e r a l Ot h e r in it ia liza t io n a n d e n a b le in t e r r u p t s if a p p lic a b le P e r ip h e r a l M o d ific a t io n Dis a b le g lo b a l in t e r r u p t s U n lo c k p e r ip h e r a l S a n it y Ch e c k M o d ify p e r ip h e r a l Lo c k p e r ip h e r a l E n a b le g lo b a l in t e r r u p t s 11.2.3 Why Disable Interrupts Global interrupts must be disabled while a peripheral is unlocked as an interrupt handler would not know the current state of the peripheral lock. If the interrupt tries to alter the lock state, it can cause an exception as it potentially tries to unlock an already unlocked peripheral. Reading current lock state is to be avoided as it removes the security provided by the PAC (Reading Lock State). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 238 Note Global interrupts should also be disabled when a peripheral is unlocked inside an interrupt handler. An example to illustrate the potential hazard of not disabling interrupts is shown in Figure 11-2: Why Disable Interrupts on page 239. Figure 11-2. Why Disable Interrupts M a in r o u t in e In it ia lize a n d lo c k p e r ip h e r a ls Use r cod e U n lo c k p e r ip h e r a l M o d ify p e r ip h e r a l In t e r r u p t In t e r r u p t h a n d le r Lo c k p e r ip h e r a l U n lo c k p e r ip h e r a l M o d ify p e r ip h e r a l E xc e p t io n Lo c k p e r ip h e r a l 11.2.4 Run-away Code Run-away code can be caused by the MCU being operated outside its specification, faulty code or EMI issues. If a run-away code occurs, it is favorable to catch the issue as soon as possible. With a correct implementation of the PAC, the run-away code can potentially be stopped. A graphical example showing how a PAC implementation will behave for different circumstances of run-away code in shown in Figure 11-3: Run-away Code on page 240 and Figure 11-4: Run-away Code on page 241. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 239 Figure 11-3. Run-away Code 1 . Ru n -a w a y c o d e is c a u g h t in s a n it y c h2e. cRu k . n -a w a y c o d e is c a u g h t w h e n m o d ifyin g A CP U e xc e p t io n is e xe c u t e d . lo c k e d p e r ip h e r a l. A CP U e xc e p t io n is e xe c u t e d . Ru n -a w a y c o d e P C# Ru n -a w a y c o d e Co d e P C# Co d e 0 x0 0 2 0 in it ia lize p e r ip h e r a l 0 x0 0 2 0 in it ia lize p e r ip h e r a l 0 x0 0 2 5 0 x0 0 2 5 ... lo c k p e r ip h e r a l ... ... 0 x0 0 8 0 s e t s a n it y a r g u m e n t ... ... lo c k p e r ip h e r a l ... 0 x0 0 8 0 s e t s a n it y a r g u m e n t ... ... 0 x0 1 1 5 d is a b le in t e r r u p t s 0 x0 1 1 5 d is a b le in t e r r u p t s 0 x0 1 2 0 u n lo c k p e r ip h e r a l 0 x0 1 2 0 u n lo c k p e r ip h e r a l 0 x0 1 2 5c h e c k s a n it y a r g u m e n t 0 x0 1 2 5c h e c k s a n it y a r g u m e n t 0 x0 1 3 0 m o d ify p e r ip h e r a l 0 x0 1 3 0 m o d ify p e r ip h e r a l 0 x0 1 4 0 0 x0 1 4 0 lo c k p e r ip h e r a l 0 x0 1 4 5 d is a b le in t e r r u p t s lo c k p e r ip h e r a l 0 x0 1 4 5 d is a b le in t e r r u p t s AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 240 Figure 11-4. Run-away Code 3 . Ru n -a w a y c o d e is c a u g h t w h e n lo c k in g 4 . Ru n -a w a y c o d e is n o t c a u g h t . lo c k e d p e r ip h e r a l. A CP U e xc e p t io n is e xe c u t e d . Ru n -a w a y c o d e P C# Ru n -a w a y c o d e Co d e P C# Co d e 0 x0 0 2 0 in it ia lize p e r ip h e r a l 0 x0 0 2 0 in it ia lize p e r ip h e r a l 0 x0 0 2 5 0 x0 0 2 5 ... lo c k p e r ip h e r a l ... ... 0 x0 0 8 0 s e t s a n it y a r g u m e n t ... ... lo c k p e r ip h e r a l ... 0 x0 0 8 0 s e t s a n it y a r g u m e n t ... ... 0 x0 1 1 5 d is a b le in t e r r u p t s 0 x0 1 1 5 d is a b le in t e r r u p t s 0 x0 1 2 0 u n lo c k p e r ip h e r a l 0 x0 1 2 0 u n lo c k p e r ip h e r a l 0 x0 1 2 5c h e c k s a n it y a r g u m e n t 0 x0 1 2 5c h e c k s a n it y a r g u m e n t 0 x0 1 3 0 m o d ify p e r ip h e r a l 0 x0 1 3 0 m o d ify p e r ip h e r a l 0 x0 1 4 0 0 x0 1 4 0 lo c k p e r ip h e r a l 0 x0 1 4 5 d is a b le in t e r r u p t s lo c k p e r ip h e r a l 0 x0 1 4 5 d is a b le in t e r r u p t s In the example, green indicates that the command is allowed, red indicates where the run-away code will be caught, and the arrow where the run-away code enters the application. In special circumstances, like example 4 above, the run-away code will not be caught. However, the protection scheme will greatly enhance peripheral configuration security from being affected by run-away code. 11.2.4.1 Key-Argument To protect the module functions against run-away code themselves, a key is required as one of the input arguments. The key-argument will make sure that run-away code entering the function without a function call will be rejected before inflicting any damage. The argument is simply set to be the bitwise inverse of the module flag, i.e. system_peripheral_<lock_state>(SYSTEM_PERIPHERAL_<module>, ~SYSTEM_PERIPHERAL_<module>); Where the lock state can be either lock or unlock, and module refer to the peripheral that is to be locked/unlocked. 11.2.5 Faulty Module Pointer The PAC also protects the application from user errors such as the use of incorrect module pointers in function arguments, given that the module is locked. It is therefore recommended that any unused peripheral is locked during application initialization. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 241 11.2.6 Use of __no_inline Using the function attribute __no_inline will ensure that there will only be one copy of each functions in the PAC driver API in the application. This will lower the likelihood that run-away code will hit any of these functions. 11.2.7 Physical Connection Figure 11-5: Physical Connection on page 242 shows how this module is interconnected within the device. Figure 11-5. Physical Connection P AC Re a d /Wr it e P e r ip h e r a l b u s Re a d /Wr it e Lo c k Op e n Re a d Re a d /Wr it e P e r ip h e r a l1 P e r ip h e r a l2 Re a d /Wr it e Op e n 11.3 Special Considerations 11.3.1 Non-Writable Registers Re a d /Wr it e P e r ip h e r a l3 Not all registers in a given peripheral can be set non-writable. Which registers this applies to is showed in List of Non-Write Protected Registers and the peripheral's subsection "Register Access Protection" in the device datasheet. 11.3.2 Reading Lock State Reading the state of the peripheral lock is to be avoided as it greatly compromises the protection initially provided by the PAC. If a lock/unlock is implemented conditionally, there is a risk that eventual errors are not caught in the protection scheme. Examples indicating the issue are shown in Figure 11-6: Reading Lock State on page 243. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 242 Figure 11-6. Reading Lock State 1 . Wr o n g im p le m e n t a t io n . Ru n -a w a y c o d e w it h p e r ip h e r a l u n lo c k e d P C# Co d e ... ... 0 x0 1 0 0 2 . Co r r e c t im p le m e n t a t io n . Ru n -a w a y c o d e w it h p e r ip h e r a l u n lo c k e d c h e c k if lo c k e d 0 x0 1 0 2 d is a b le in t e r r u p t s 0 x0 1 0 5 u n lo c k if lo c k e d 0 x0 1 1 0 c h e c k s a n it y 0 x0 1 1 5 m o d ify p e r ip h e r a l 0 x0 1 2 0lo c k if p r e vio u s ly lo c k e d 0 x0 1 2 5 e n a b le in t e r r u p t s P C# Co d e ... ... 0 x0 1 0 0 d is a b le in t e r r u p t s 0 x0 1 2 0 u n lo c k p e r ip h e r a l 0 x0 1 2 5c h e c k s a n it y a r g u m e n t 0 x0 1 3 0 m o d ify p e r ip h e r a l 0 x0 1 4 0 lo c k p e r ip h e r a l 0 x0 1 4 5 d is a b le in t e r r u p t s In the left figure above, one can see the run-away code continues as all illegal operations are conditional. On the right side figure, the run-away code is caught as it tries to unlock the peripheral. 11.4 Extra Information For extra information, see Extra Information for PAC Driver. This includes: 11.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for PAC Driver. 11.6 API Overview 11.6.1 Macro Definitions 11.6.1.1 Macro SYSTEM_PERIPHERAL_ID AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 243 #define SYSTEM_PERIPHERAL_ID(peripheral) \ ID_##peripheral Retrieves the ID of a specified peripheral name, giving its peripheral bus location. Table 11-1. Parameters Data direction Parameter name Description [in] peripheral Name of the peripheral instance Returns 11.6.2 Bus ID of the specified peripheral instance. Function Definitions 11.6.2.1 Peripheral Lock and Unlock Function system_peripheral_lock() Lock a given peripheral's control registers. __no_inline enum status_code system_peripheral_lock( const uint32_t peripheral_id, const uint32_t key) 2 Support and FAQ: visit Atmel Support Locks a given peripheral's control registers, to deny write access to the peripheral to prevent accidental changes to the module's configuration. Warning Locking an already locked peripheral will cause a hard fault exception, and terminate program execution. Table 11-2. Parameters Returns Data direction Parameter name Description [in] peripheral_id ID for the peripheral to be locked, sourced via the SYSTEM_PERIPHERAL_ID macro. [in] key Bitwise inverse of peripheral ID, used as key to reduce the chance of accidental locking. See KeyArgument. Status of the peripheral lock procedure. Table 11-3. Return Values 2 Return value Description STATUS_OK If the peripheral was successfully locked. http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 244 Return value Description STATUS_ERR_INVALID_ARG If invalid argument(s) were supplied. Function system_peripheral_unlock() Unlock a given peripheral's control registers. __no_inline enum status_code system_peripheral_unlock( const uint32_t peripheral_id, const uint32_t key) Unlocks a given peripheral's control registers, allowing write access to the peripheral so that changes can be made to the module's configuration. Warning Unlocking an already locked peripheral will cause a hard fault exception, and terminate program execution. Table 11-4. Parameters Data direction Parameter name Description [in] peripheral_id ID for the peripheral to be unlocked, sourced via the SYSTEM_PERIPHERAL_ID macro. [in] key Bitwise inverse of peripheral ID, used as key to reduce the chance of accidental unlocking. See KeyArgument. Returns Status of the peripheral unlock procedure. Table 11-5. Return Values 11.7 Return value Description STATUS_OK If the peripheral was successfully locked. STATUS_ERR_INVALID_ARG If invalid argument(s) were supplied. List of Non-Write Protected Registers Look in device datasheet peripheral's subsection "Register Access Protection" to see which is actually available for your device. Module Non-write protected register AC INTFLAG STATUSA STATUSB STATUSC AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 245 Module Non-write protected register ADC INTFLAG STATUS RESULT EVSYS INTFLAG CHSTATUS NVMCTRL INTFLAG STATUS PM INTFLAG PORT N/A RTC INTFLAG READREQ STATUS SYSCTRL INTFLAG SERCOM INTFALG STATUS DATA TC INTFLAG STATUS WDT INTFLAG STATUS (CLEAR) 11.8 Extra Information for PAC Driver 11.8.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. Acronym Description AC Analog Comparator ADC Analog-to-Digital Converter EVSYS Event System NMI Non-Maskable Interrupt NVMCTRL Non-Volatile Memory Controller PAC Peripheral Access Controller PM Power Manager RTC Real-Time Counter SERCOM Serial Communication Interface SYSCTRL System Controller TC Timer/Counter AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 246 11.8.2 Acronym Description WDT Watch Dog Timer Dependencies This driver has the following dependencies: ● 11.8.3 None Errata There are no errata related to this driver. 11.8.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAMD21 Initial Release 11.9 Examples for PAC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Peripheral Access Controller Driver (PAC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_pac_basic_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 247 12. SAM Port Driver (PORT) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's General Purpose Input/Output (GPIO) pin functionality, for manual pin state reading and writing. The following peripherals are used by this module: ● PORT (GPIO Management) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 12.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 12.2 Module Overview The device GPIO (PORT) module provides an interface between the user application logic and external hardware peripherals, when general pin state manipulation is required. This driver provides an easy-to-use interface to the physical pin input samplers and output drivers, so that pins can be read from or written to for general purpose external hardware control. 12.2.1 Driver Feature Macro Definition Note 12.2.2 Driver Feature Macro Supported devices FEATURE_PORT_INPUT_EVENT SAML21 The specific features are only available in the driver when the selected device supports those features. Physical and Logical GPIO Pins SAM devices use two naming conventions for the I/O pins in the device; one physical and one logical. Each physical pin on a device package is assigned both a physical port and pin identifier (e.g. "PORTA.0") as well as a 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 248 monotonically incrementing logical GPIO number (e.g. "GPIO0"). While the former is used to map physical pins to their physical internal device module counterparts, for simplicity the design of this driver uses the logical GPIO numbers instead. 12.2.3 Physical Connection Figure 12-1: Physical Connection on page 249 shows how this module is interconnected within the device. Figure 12-1. Physical Connection Por t Pa d P e r ip h e r a l M U X GP IO M o d u le 12.3 Ot h e r P e r ip h e r a l M o d u le s Special Considerations The SAM port pin input sampler can be disabled when the pin is configured in pure output mode to save power; reading the pin state of a pin configured in output-only mode will read the logical output state that was last set. 12.4 Extra Information For extra information, see Extra Information for PORT Driver. This includes: 12.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for PORT Driver. 12.6 API Overview 12.6.1 Structure Definitions 12.6.1.1 Struct port_config Configuration structure for a port pin instance. This structure should be initialized by the port_get_config_defaults() function before being modified by the user application. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 249 Table 12-1. Members Type Name Description enum port_pin_dir direction Port buffer input/output direction. enum port_pin_pull input_pull Port pull-up/pull-down for input pins. bool powersave Enable lowest possible powerstate 1 on the pin Notes: 12.6.2 1 All other configurations will be ignored, the pin will be disabled. Macro Definitions 12.6.2.1 PORT Alias Macros Macro PORTA #define PORTA PORT->Group[0] Convenience definition for GPIO module group A on the device (if available). Macro PORTB #define PORTB PORT->Group[1] Convenience definition for GPIO module group B on the device (if available). Macro PORTC #define PORTC PORT->Group[2] Convenience definition for GPIO module group C on the device (if available). Macro PORTD #define PORTD PORT->Group[3] Convenience definition for GPIO module group D on the device (if available). 12.6.3 Function Definitions 12.6.3.1 State Reading/Writing (Physical Group Orientated) Function port_get_group_from_gpio_pin() Retrieves the PORT module group instance from a given GPIO pin number. PortGroup * port_get_group_from_gpio_pin( const uint8_t gpio_pin) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 250 Retrieves the PORT module group instance associated with a given logical GPIO pin number. Table 12-2. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to convert Returns Base address of the associated PORT module. Function port_group_get_input_level() Retrieves the state of a group of port pins that are configured as inputs. uint32_t port_group_get_input_level( const PortGroup *const port, const uint32_t mask) Reads the current logic level of a port module's pins and returns the current levels as a bitmask. Table 12-3. Parameters Data direction Parameter name Description [in] port Base of the PORT module to read from [in] mask Mask of the port pin(s) to read Returns Status of the port pin(s) input buffers. Function port_group_get_output_level() Retrieves the state of a group of port pins that are configured as outputs. uint32_t port_group_get_output_level( const PortGroup *const port, const uint32_t mask) Reads the current logical output level of a port module's pins and returns the current levels as a bitmask. Table 12-4. Parameters Returns Data direction Parameter name Description [in] port Base of the PORT module to read from [in] mask Mask of the port pin(s) to read Status of the port pin(s) output buffers. Function port_group_set_output_level() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 251 Sets the state of a group of port pins that are configured as outputs. void port_group_set_output_level( PortGroup *const port, const uint32_t mask, const uint32_t level_mask) Sets the current output level of a port module's pins to a given logic level. Table 12-5. Parameters Data direction Parameter name Description [out] port Base of the PORT module to write to [in] mask Mask of the port pin(s) to change [in] level_mask Mask of the port level(s) to set Function port_group_toggle_output_level() Toggles the state of a group of port pins that are configured as an outputs. void port_group_toggle_output_level( PortGroup *const port, const uint32_t mask) Toggles the current output levels of a port module's pins. Table 12-6. Parameters Data direction Parameter name Description [out] port Base of the PORT module to write to [in] mask Mask of the port pin(s) to toggle 12.6.3.2 Configuration and Initialization Function port_get_config_defaults() Initializes a Port pin/group configuration structure to defaults. void port_get_config_defaults( struct port_config *const config) Initializes a given Port pin/group configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Input mode with internal pullup enabled Table 12-7. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 252 Function port_pin_set_config() Writes a Port pin configuration to the hardware module. void port_pin_set_config( const uint8_t gpio_pin, const struct port_config *const config) 2 Support and FAQ: visit Atmel Support Writes out a given configuration of a Port pin configuration to the hardware module. Note If the pin direction is set as an output, the pull-up/pull-down input configuration setting is ignored. Table 12-8. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to configure [in] config Configuration settings for the pin Function port_group_set_config() Writes a Port group configuration group to the hardware module. void port_group_set_config( PortGroup *const port, const uint32_t mask, const struct port_config *const config) Writes out a given configuration of a Port group configuration to the hardware module. Note If the pin direction is set as an output, the pull-up/pull-down input configuration setting is ignored. Table 12-9. Parameters Data direction Parameter name Description [out] port Base of the PORT module to write to [in] mask Mask of the port pin(s) to configure [in] config Configuration settings for the pin group 12.6.3.3 State Reading/Writing (Logical Pin Orientated) Function port_pin_get_input_level() 2 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 253 Retrieves the state of a port pin that is configured as an input. bool port_pin_get_input_level( const uint8_t gpio_pin) Reads the current logic level of a port pin and returns the current level as a Boolean value. Table 12-10. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to read Returns Status of the port pin's input buffer. Function port_pin_get_output_level() Retrieves the state of a port pin that is configured as an output. bool port_pin_get_output_level( const uint8_t gpio_pin) Reads the current logical output level of a port pin and returns the current level as a Boolean value. Table 12-11. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to read Returns Status of the port pin's output buffer. Function port_pin_set_output_level() Sets the state of a port pin that is configured as an output. void port_pin_set_output_level( const uint8_t gpio_pin, const bool level) Sets the current output level of a port pin to a given logic level. Table 12-12. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to write to [in] level Logical level to set the given pin to Function port_pin_toggle_output_level() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 254 Toggles the state of a port pin that is configured as an output. void port_pin_toggle_output_level( const uint8_t gpio_pin) Toggles the current output level of a port pin. Table 12-13. Parameters 12.6.4 Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to toggle Enumeration Definitions 12.6.4.1 Enum port_pin_dir Enum for the possible pin direction settings of the port pin configuration structure, to indicate the direction the pin should use. Table 12-14. Members Enum value Description PORT_PIN_DIR_INPUT The pin's input buffer should be enabled, so that the pin state can be read. PORT_PIN_DIR_OUTPUT The pin's output buffer should be enabled, so that the pin state can be set. PORT_PIN_DIR_OUTPUT_WTH_READBACK The pin's output and input buffers should be enabled, so that the pin state can be set and read back. 12.6.4.2 Enum port_pin_pull Enum for the possible pin pull settings of the port pin configuration structure, to indicate the type of logic level pull the pin should use. Table 12-15. Members Enum value Description PORT_PIN_PULL_NONE No logical pull should be applied to the pin. PORT_PIN_PULL_UP Pin should be pulled up when idle. PORT_PIN_PULL_DOWN Pin should be pulled down when idle. 12.7 Extra Information for PORT Driver 12.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. Acronym Description GPIO General Purpose Input/Output MUX Multiplexer AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 255 12.7.2 Dependencies This driver has the following dependencies: ● 12.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 12.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added input event feature and support for SAML21 Added support for SAMD21 Initial Release 12.8 Examples for PORT Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Port Driver (PORT). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● 12.8.1 Quick Start Guide for PORT - Basic Quick Start Guide for PORT - Basic In this use case, the PORT module is configured for: ● One pin in input mode, with pull-up enabled ● One pin in output mode This use case sets up the PORT to read the current state of a GPIO pin set as an input, and mirrors the opposite logical state on a pin configured as an output. 12.8.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_port_pins(void) { struct port_config config_port_pin; port_get_config_defaults(&config_port_pin); config_port_pin.direction = PORT_PIN_DIR_INPUT; config_port_pin.input_pull = PORT_PIN_PULL_UP; port_pin_set_config(BUTTON_0_PIN, &config_port_pin); config_port_pin.direction = PORT_PIN_DIR_OUTPUT; port_pin_set_config(LED_0_PIN, &config_port_pin); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 256 } Add to user application initialization (typically the start of main()): configure_port_pins(); Workflow 1. Create a PORT module pin configuration struct, which can be filled out to adjust the configuration of a single port pin. struct port_config config_port_pin; 2. Initialize the pin configuration struct with the module's default values. port_get_config_defaults(&config_port_pin); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to request an input pin. config_port_pin.direction = PORT_PIN_DIR_INPUT; config_port_pin.input_pull = PORT_PIN_PULL_UP; 4. Configure push button pin with the initialized pin configuration struct, to enable the input sampler on the pin. port_pin_set_config(BUTTON_0_PIN, &config_port_pin); 5. Adjust the configuration struct to request an output pin. config_port_pin.direction = PORT_PIN_DIR_OUTPUT; Note The existing configuration struct may be re-used, as long as any values that have been altered from the default settings are taken into account by the user application. 6. Configure LED pin with the initialized pin configuration struct, to enable the output driver on the pin. port_pin_set_config(LED_0_PIN, &config_port_pin); 12.8.1.2 Use Case Code Copy-paste the following code to your user application: while (true) { bool pin_state = port_pin_get_input_level(BUTTON_0_PIN); port_pin_set_output_level(LED_0_PIN, !pin_state); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 257 } Workflow 1. Read in the current input sampler state of push button pin, which has been configured as an input in the usecase setup code. bool pin_state = port_pin_get_input_level(BUTTON_0_PIN); 2. Write the inverted pin level state to LED pin, which has been configured as an output in the use-case setup code. port_pin_set_output_level(LED_0_PIN, !pin_state); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 258 13. SAM RTC Calendar Driver (RTC CAL) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Real Time Clock functionality in Calendar operating mode, for the configuration and retrieval of the current time and date as maintained by the RTC module. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● RTC (Real Time Clock) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 13.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 13.2 Module Overview The RTC module in the SAM devices is a 32-bit counter, with a 10-bit programmable prescaler. Typically, the RTC clock is run continuously, including in the device's low-power sleep modes, to track the current time and date information. The RTC can be used as a source to wake up the system at a scheduled time or periodically using the alarm functions. In this driver, the RTC is operated in Calendar mode. This allows for an easy integration of a real time clock and calendar into a user application to track the passing of time and/or perform scheduled tasks. Whilst operating in Calendar mode, the RTC features: ● Time tracking in seconds, minutes, and hours ● 12 or 24 hour mode ● Date tracking in day, month, and year 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 259 ● 13.2.1 Automatic leap year correction Driver Feature Macro Definition Driver Feature Macro Supported devices FEATURE_RTC_PERIODIC_INT SAML21 FEATURE_RTC_PRESCALER_OFF SAML21 FEATURE_RTC_CLOCK_SELECTION SAML21 FEATURE_RTC_GENERAL_PURPOSE_REG SAML21 FEATURE_RTC_CONTINUOUSLY_UPDATED SAMD20, SAMD21, SAMR21, SAMD10, SAMD11 Note 13.2.2 The specific features are only available in the driver when the selected device supports those features. Alarms and Overflow The RTC has four independent hardware alarms that can be configured by the user application. These alarms will be will triggered on match with the current clock value, and can be set up to trigger an interrupt, event, or both. The RTC can also be configured to clear the clock value on alarm match, resetting the clock to the original start time. If the RTC is operated in clock-only mode (i.e. with calendar disabled), the RTC counter value will instead be cleared on overflow once the maximum count value has been reached: (13.1) When the RTC is operated with the calendar enabled and run using a nominal 1Hz input clock frequency, a register overflow will occur after 64 years. 13.2.3 Periodic Events The RTC can generate events at periodic intervals, allowing for direct peripheral actions without CPU intervention. The periodic events can be generated on the upper eight bits of the RTC prescaler, and will be generated on the rising edge transition of the specified bit. The resulting periodic frequency can be calculated by the following formula: (13.2) Where (13.3) refers to the asynchronous clock set up in the RTC module configuration. For the RTC to operate correctly in calendar mode, this frequency must be 1KHz, while the RTC's internal prescaler should be set to divide by 1024. The n parameter is the event source generator index of the RTC module. If the asynchronous clock is operated at the recommended 1KHz, the formula results in the values shown in Table 13-1: RTC Event Frequencies for Each Prescaler Bit Using a 1KHz Clock on page 260. Table 13-1. RTC Event Frequencies for Each Prescaler Bit Using a 1KHz Clock n Periodic event 7 1Hz 6 2Hz 5 4Hz 4 8Hz 3 16Hz AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 260 n Periodic event 2 32Hz 1 64Hz 0 128Hz Note 13.2.4 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Digital Frequency Correction The RTC module contains Digital Frequency Correction logic to compensate for inaccurate source clock frequencies which would otherwise result in skewed time measurements. The correction scheme requires that at least two bits in the RTC module prescaler are reserved by the correction logic. As a result of this implementation, frequency correction is only available when the RTC is running from a 1Hz reference clock. The correction procedure is implemented by subtracting or adding a single cycle from the RTC prescaler every 1024 RTC GCLK cycles. The adjustment is applied the specified number of time (maximum 127) over 976 of these periods. The corresponding correction in PPM will be given by: (13.4) The RTC clock will tick faster if provided with a positive correction value, and slower when given a negative correction value. 13.3 Special Considerations 13.3.1 Year Limit The RTC module has a year range of 63 years from the starting year configured when the module is initialized. Dates outside the start to end year range described below will need software adjustment: (13.5) 13.3.2 Clock Setup 13.3.2.1 SAM D20/D21/R21/D10/D11 Clock Setup The RTC is typically clocked by a specialized GCLK generator that has a smaller prescaler than the others. By default the RTC clock is on, selected to use the internal 32KHz RC-oscillator with a prescaler of 32, giving a resulting clock frequency of 1024Hz to the RTC. When the internal RTC prescaler is set to 1024, this yields an endfrequency of 1Hz for correct time keeping operations. The implementer also has the option to set other end-frequencies. Table 13-2: RTC Output Frequencies from Allowable Input Clocks on page 261 lists the available RTC frequencies for each possible GCLK and RTC input prescaler options. Table 13-2. RTC Output Frequencies from Allowable Input Clocks End-frequency GCLK prescaler RTC prescaler 32KHz 1 1 1KHz 32 1 1Hz 32 1024 The overall RTC module clocking scheme is shown in Figure 13-1: SAM D20/D21/R21/D10/D11 Clock Setup on page 262. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 261 Figure 13-1. SAM D20/D21/R21/D10/D11 Clock Setup Note GCLK RTC RTC RTC_GCLK RTC P RE S CALE R RTC CLOCK For the calendar to operate correctly, an asynchronous clock of 1Hz should be used. 13.3.2.2 SAM L21 Clock Setup The RTC clock can be selected from OSC32K,XOSC32K or OSCULP32K , and a 32KHz or 1KHz oscillator clock frequency is required. This clock must be configured and enabled in the 32KHz oscillator controller before using the RTC. The table below lists the available RTC clock Table 13-3: RTC clocks source on page 262 Table 13-3. RTC clocks source Note 13.4 RTC clock frequency Clock source Description 1.024KHz ULP1K 1.024KHz from 32KHz internal ULP oscillator 32.768KHz ULP32K 32.768KHz from 32KHz internal ULP oscillator 1.024KHz OSC1K 1.024KHz from 32KHz internal oscillator 32.768KHz OSC32K 32.768KHz from 32KHz internal oscillator 1.024KHz XOSC1K 1.024KHz from 32KHz internal oscillator 32.768KHz XOSC32K 32.768KHz from 32KHz external crystal oscillator For the calendar to operate correctly, an asynchronous clock of 1Hz should be used. Extra Information For extra information, see Extra Information for RTC (CAL) Driver. This includes: 13.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for RTC CAL Driver. 13.6 API Overview 13.6.1 Structure Definitions 13.6.1.1 Struct rtc_calendar_alarm_time AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 262 Alarm structure containing time of the alarm and a mask to determine when the alarm will trigger. Table 13-4. Members Type Name Description enum rtc_calendar_alarm_mask mask Alarm mask to determine on what precision the alarm will match. struct rtc_calendar_time time Alarm time. 13.6.1.2 Struct rtc_calendar_config Configuration structure for the RTC instance. This structure should be initialized using the rtc_calendar_get_config_defaults() before any user configurations are set. Table 13-5. Members Type Name Description struct rtc_calendar_alarm_time alarm[] Alarm values. bool clear_on_match If true, clears the clock on alarm match. bool clock_24h If true, time is represented in 24 hour mode. bool continuously_update If true, the digital counter registers will be continuously updated so that internal synchronization is not needed when reading the current count. enum rtc_calendar_prescaler prescaler Input clock prescaler for the RTC module. uint16_t year_init_value Initial year for counter value 0. 13.6.1.3 Struct rtc_calendar_events Event flags for the rtc_calendar_enable_events() and rtc_calendar_disable_events(). Table 13-6. Members Type Name Description bool generate_event_on_alarm[] Generate an output event on a alarm channel match against the RTC count. bool generate_event_on_overflow Generate an output event on each overflow of the RTC count. bool generate_event_on_periodic[] Generate an output event periodically at a binary division of the RTC counter frequency. 13.6.1.4 Struct rtc_calendar_time Time structure containing the time given by or set to the RTC calendar. The structure uses seven values to give second, minute, hour, PM/AM, day, month, and year. It should be initialized via the rtc_calendar_get_time_defaults() function before use. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 263 Table 13-7. Members 13.6.2 Type Name Description uint8_t day Day value, where day 1 is the first day of the month. uint8_t hour Hour value. uint8_t minute Minute value. uint8_t month Month value, where month 1 is January. bool pm PM/AM value, true for PM, or false for AM. uint8_t second Second value. uint16_t year Year value. Macro Definitions 13.6.2.1 Macro FEATURE_RTC_CONTINUOUSLY_UPDATED #define FEATURE_RTC_CONTINUOUSLY_UPDATED Define port features set according to different device familyRTC continuously updated. 13.6.3 Function Definitions 13.6.3.1 Configuration and Initialization Function rtc_calendar_get_time_defaults() Initialize a time structure. void rtc_calendar_get_time_defaults( struct rtc_calendar_time *const time) This will initialize a given time structure to the time 00:00:00 (hh:mm:ss) and date 2000-01-01 (YYYY-MM-DD). Table 13-8. Parameters Data direction Parameter name Description [out] time Time structure to initialize Function rtc_calendar_get_config_defaults() Gets the RTC default settings. void rtc_calendar_get_config_defaults( struct rtc_calendar_config *const config) Initializes the configuration structure to the known default values. This function should be called at the start of any RTC initiation. The default configuration is as follows: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 264 ● Input clock divided by a factor of 1024 ● Clear on alarm match off ● Continuously sync clock off ● 12 hour calendar ● Start year 2000 (Year 0 in the counter will be year 2000) ● Events off ● Alarms set to January 1. 2000, 00:00:00 ● Alarm will match on second, minute, hour, day, month, and year Table 13-9. Parameters Data direction Parameter name Description [out] config Configuration structure to be initialized to default values. Function rtc_calendar_reset() Resets the RTC module Resets the RTC module to hardware defaults. void rtc_calendar_reset( struct rtc_module *const module) Table 13-10. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function rtc_calendar_enable() Enables the RTC module. void rtc_calendar_enable( struct rtc_module *const module) Enables the RTC module once it has been configured, ready for use. Most module configuration parameters cannot be altered while the module is enabled. Table 13-11. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function rtc_calendar_disable() Disables the RTC module. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 265 void rtc_calendar_disable( struct rtc_module *const module) Disables the RTC module. Table 13-12. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function rtc_calendar_init() Initializes the RTC module with given configurations. void rtc_calendar_init( struct rtc_module *const module, Rtc *const hw, const struct rtc_calendar_config *const config) Initializes the module, setting up all given configurations to provide the desired functionality of the RTC. Table 13-13. Parameters Data direction Parameter name Description [out] module Pointer to the software instance struct [in] hw Pointer to hardware instance [in] config Pointer to the configuration structure. Function rtc_calendar_swap_time_mode() Swaps between 12h and 24h clock mode. void rtc_calendar_swap_time_mode( struct rtc_module *const module) Swaps the current RTC time mode: Note ● If currently in 12h mode, it will swap to 24h ● If currently in 24h mode, it will swap to 12h This will not change setting in user's configuration structure. Table 13-14. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 266 Function rtc_calendar_frequency_correction() Calibrate for too-slow or too-fast oscillator. enum status_code rtc_calendar_frequency_correction( struct rtc_module *const module, const int8_t value) When used, the RTC will compensate for an inaccurate oscillator. The RTC module will add or subtract cycles from the RTC prescaler to adjust the frequency in approximately 1 PPM steps. The provided correction value should be between -127 and 127, allowing for a maximum 127 PPM correction in either direction. If no correction is needed, set value to zero. Note Can only be used when the RTC is operated at 1Hz. Table 13-15. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] value Between -127 and 127 used for the correction. Status of the calibration procedure. Table 13-16. Return Values Return value Description STATUS_OK If calibration was done correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. 13.6.3.2 Time and Alarm Management Function rtc_calendar_set_time() Set the current calendar time to desired time. void rtc_calendar_set_time( struct rtc_module *const module, const struct rtc_calendar_time *const time) Sets the time provided to the calendar. Table 13-17. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 267 Data direction Parameter name Description [in] time The time to set in the calendar. Function rtc_calendar_get_time() Get the current calendar value. void rtc_calendar_get_time( struct rtc_module *const module, struct rtc_calendar_time *const time) Retrieves the current time of the calendar. Table 13-18. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [out] time Pointer to value that will be filled with current time. Function rtc_calendar_set_alarm() Set the alarm time for the specified alarm. enum status_code rtc_calendar_set_alarm( struct rtc_module *const module, const struct rtc_calendar_alarm_time *const alarm, const enum rtc_calendar_alarm alarm_index) Sets the time and mask specified to the requested alarm. Table 13-19. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] alarm The alarm struct to set the alarm with. [in] alarm_index The index of the alarm to set. Status of setting alarm. Table 13-20. Return Values Return value Description STATUS_OK If alarm was set correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. Function rtc_calendar_get_alarm() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 268 Get the current alarm time of specified alarm. enum status_code rtc_calendar_get_alarm( struct rtc_module *const module, struct rtc_calendar_alarm_time *const alarm, const enum rtc_calendar_alarm alarm_index) Retrieves the current alarm time for the alarm specified. Table 13-21. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [out] alarm Pointer to the struct that will be filled with alarm time and mask of the specified alarm. [in] alarm_index Index of alarm to get alarm time from. Returns Status of getting alarm. Table 13-22. Return Values Return value Description STATUS_OK If alarm was read correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. 13.6.3.3 Status Flag Management Function rtc_calendar_is_overflow() Check if an RTC overflow has occurred. bool rtc_calendar_is_overflow( struct rtc_module *const module) Checks the overflow flag in the RTC. The flag is set when there is an overflow in the clock. Table 13-23. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Returns Overflow state of the RTC module. Table 13-24. Return Values Return value Description true If the RTC count value has overflowed AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 269 Return value Description false If the RTC count value has not overflowed Function rtc_calendar_clear_overflow() Clears the RTC overflow flag. void rtc_calendar_clear_overflow( struct rtc_module *const module) Table 13-25. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Clears the RTC module counter overflow flag, so that new overflow conditions can be detected. Function rtc_calendar_is_alarm_match() Check the RTC alarm flag. bool rtc_calendar_is_alarm_match( struct rtc_module *const module, const enum rtc_calendar_alarm alarm_index) Check if the specified alarm flag is set. The flag is set when there is an compare match between the alarm value and the clock. Table 13-26. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] alarm_index Index of the alarm to check Returns Match status of the specified alarm. Table 13-27. Return Values Return value Description true If the specified alarm has matched the current time false If the specified alarm has not matched the current time Function rtc_calendar_clear_alarm_match() Clears the RTC alarm match flag. enum status_code rtc_calendar_clear_alarm_match( struct rtc_module *const module, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 270 const enum rtc_calendar_alarm alarm_index) Clear the requested alarm match flag, so that future alarm matches can be determined. Table 13-28. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] alarm_index The index of the alarm match to clear Returns Status of the alarm match clear operation. Table 13-29. Return Values Return value Description STATUS_OK If flag was cleared correctly STATUS_ERR_INVALID_ARG If invalid argument(s) were provided 13.6.3.4 Event Management Function rtc_calendar_enable_events() Enables a RTC event output. void rtc_calendar_enable_events( struct rtc_module *const module, struct rtc_calendar_events *const events) Enables one or more output events from the RTC module. See rtc_calendar_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 13-30. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] events Struct containing flags of events to enable Function rtc_calendar_disable_events() Disables a RTC event output. void rtc_calendar_disable_events( struct rtc_module *const module, struct rtc_calendar_events *const events) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 271 Disabled one or more output events from the RTC module. See rtc_calendar_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 13-31. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] events Struct containing flags of events to disable 13.6.3.5 Callbacks Function rtc_calendar_register_callback() Registers callback for the specified callback type. enum status_code rtc_calendar_register_callback( struct rtc_module *const module, rtc_calendar_callback_t callback, enum rtc_calendar_callback callback_type) Associates the given callback function with the specified callback type. To enable the callback, the rtc_calendar_enable_callback function must be used. Table 13-32. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback Pointer to the function desired for the specified callback [in] callback_type Callback type to register Status of registering callback. Table 13-33. Return Values Return value Description STATUS_OK Registering was done successfully STATUS_ERR_INVALID_ARG If trying to register a callback not available Function rtc_calendar_unregister_callback() Unregisters callback for the specified callback type. enum status_code rtc_calendar_unregister_callback( struct rtc_module *const module, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 272 enum rtc_calendar_callback callback_type) When called, the currently registered callback for the given callback type will be removed. Table 13-34. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback_type Specifies the callback type to unregister Returns Status of unregistering callback. Table 13-35. Return Values Return value Description STATUS_OK Unregistering was done successfully STATUS_ERR_INVALID_ARG If trying to unregister a callback not available Function rtc_calendar_enable_callback() Enables callback. void rtc_calendar_enable_callback( struct rtc_module *const module, enum rtc_calendar_callback callback_type) Enables the callback specified by the callback_type. Table 13-36. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback_type Callback type to enable Function rtc_calendar_disable_callback() Disables callback. void rtc_calendar_disable_callback( struct rtc_module *const module, enum rtc_calendar_callback callback_type) Disables the callback specified by the callback_type. Table 13-37. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 273 13.6.4 Data direction Parameter name Description [in] callback_type Callback type to disable Enumeration Definitions 13.6.4.1 Enum rtc_calendar_alarm Available alarm channels. Note Not all alarm channels are available on all devices. Table 13-38. Members Enum value Description RTC_CALENDAR_ALARM_0 Alarm channel 0. RTC_CALENDAR_ALARM_1 Alarm channel 1. RTC_CALENDAR_ALARM_2 Alarm channel 2. RTC_CALENDAR_ALARM_3 Alarm channel 3. 13.6.4.2 Enum rtc_calendar_alarm_mask Available mask options for alarms. Table 13-39. Members Enum value Description RTC_CALENDAR_ALARM_MASK_DISABLED Alarm disabled. RTC_CALENDAR_ALARM_MASK_SEC Alarm match on second. RTC_CALENDAR_ALARM_MASK_MIN Alarm match on second and minute. RTC_CALENDAR_ALARM_MASK_HOUR Alarm match on second, minute, and hour. RTC_CALENDAR_ALARM_MASK_DAY Alarm match on second, minute, hour, and day. RTC_CALENDAR_ALARM_MASK_MONTH Alarm match on second, minute, hour, day, and month. RTC_CALENDAR_ALARM_MASK_YEAR Alarm match on second, minute, hour, day, month, and year. 13.6.4.3 Enum rtc_calendar_callback The available callback types for the RTC calendar module. Table 13-40. Members Enum value Description RTC_CALENDAR_CALLBACK_ALARM_0 Callback for alarm 0. RTC_CALENDAR_CALLBACK_ALARM_1 Callback for alarm 1. RTC_CALENDAR_CALLBACK_ALARM_2 Callback for alarm 2. RTC_CALENDAR_CALLBACK_ALARM_3 Callback for alarm 3. RTC_CALENDAR_CALLBACK_OVERFLOW Callback for overflow. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 274 13.6.4.4 Enum rtc_calendar_prescaler The available input clock prescaler values for the RTC calendar module. Table 13-41. Members Enum value Description RTC_CALENDAR_PRESCALER_DIV_1 RTC input clock frequency is prescaled by a factor of 1. RTC_CALENDAR_PRESCALER_DIV_2 RTC input clock frequency is prescaled by a factor of 2. RTC_CALENDAR_PRESCALER_DIV_4 RTC input clock frequency is prescaled by a factor of 4. RTC_CALENDAR_PRESCALER_DIV_8 RTC input clock frequency is prescaled by a factor of 8. RTC_CALENDAR_PRESCALER_DIV_16 RTC input clock frequency is prescaled by a factor of 16. RTC_CALENDAR_PRESCALER_DIV_32 RTC input clock frequency is prescaled by a factor of 32. RTC_CALENDAR_PRESCALER_DIV_64 RTC input clock frequency is prescaled by a factor of 64. RTC_CALENDAR_PRESCALER_DIV_128 RTC input clock frequency is prescaled by a factor of 128. RTC_CALENDAR_PRESCALER_DIV_256 RTC input clock frequency is prescaled by a factor of 256. RTC_CALENDAR_PRESCALER_DIV_512 RTC input clock frequency is prescaled by a factor of 512. RTC_CALENDAR_PRESCALER_DIV_1024 RTC input clock frequency is prescaled by a factor of 1024. 13.7 Extra Information for RTC (CAL) Driver 13.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 13.7.2 Acronym Description RTC Real Time Counter PPM Part Per Million RC Resistor/Capacitor Dependencies This driver has the following dependencies: ● 13.7.3 None Errata There are no errata related to this driver. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 275 13.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAML21. Added support for SAMD21 and added driver instance parameter to all API function calls, except get_config_defaults Updated initialization function to also enable the digital interface clock to the module if it is disabled Initial Release 13.8 Examples for RTC CAL Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM RTC Calendar Driver (RTC CAL). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 13.8.1 ● Quick Start Guide for RTC (CAL) - Basic ● Quick Start Guide for RTC (CAL) - Callback Quick Start Guide for RTC (CAL) - Basic In this use case, the RTC is set up in calendar mode. The time is set and also an alarm is set to show a general use of the RTC in calendar mode. Also the clock is swapped from 24h to 12h mode after initialization. The board LED will be toggled once the current time matches the set time. 13.8.1.1 Prerequisites The Generic Clock Generator for the RTC should be configured and enabled; if you are using the System Clock driver, this may be done via conf_clocks.h. Clocks and Oscillators The conf_clock.h file needs to be changed with the following values to configure the clocks and oscillators for the module. The following oscillator settings are needed: /* # # # # # # SYSTEM_CLOCK_SOURCE_OSC32K configuration - Internal 32KHz oscillator */ define CONF_CLOCK_OSC32K_ENABLE true define CONF_CLOCK_OSC32K_STARTUP_TIME SYSTEM_OSC32K_STARTUP_130 define CONF_CLOCK_OSC32K_ENABLE_1KHZ_OUTPUT true define CONF_CLOCK_OSC32K_ENABLE_32KHZ_OUTPUT true define CONF_CLOCK_OSC32K_ON_DEMAND true define CONF_CLOCK_OSC32K_RUN_IN_STANDBY false The following generic clock settings are needed: /* # # # # # Configure GCLK generator 2 (RTC) */ define CONF_CLOCK_GCLK_2_ENABLE define CONF_CLOCK_GCLK_2_RUN_IN_STANDBY define CONF_CLOCK_GCLK_2_CLOCK_SOURCE define CONF_CLOCK_GCLK_2_PRESCALER define CONF_CLOCK_GCLK_2_OUTPUT_ENABLE true false SYSTEM_CLOCK_SOURCE_OSC32K 32 false AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 276 13.8.1.2 Setup Initialization Code Create an rtc_module struct and add to the main application source file, outside of any functions: struct rtc_module rtc_instance; Copy-paste the following setup code to your application: void configure_rtc_calendar(void) { /* Initialize RTC in calendar mode. */ struct rtc_calendar_config config_rtc_calendar; rtc_calendar_get_config_defaults(&config_rtc_calendar); struct rtc_calendar_time alarm; rtc_calendar_get_time_defaults(&alarm); alarm.year = 2013; alarm.month = 1; alarm.day = 1; alarm.hour = 0; alarm.minute = 0; alarm.second = 4; config_rtc_calendar.clock_24h = true; config_rtc_calendar.alarm[0].time = alarm; config_rtc_calendar.alarm[0].mask = RTC_CALENDAR_ALARM_MASK_YEAR; rtc_calendar_init(&rtc_instance, RTC, &config_rtc_calendar); } rtc_calendar_enable(&rtc_instance); Add to Main Add the following to main(). system_init(); struct rtc_calendar_time time; time.year = 2012; time.month = 12; time.day = 31; time.hour = 23; time.minute = 59; time.second = 59; configure_rtc_calendar(); /* Set current time. */ rtc_calendar_set_time(&rtc_instance, &time); rtc_calendar_swap_time_mode(&rtc_instance); Workflow 1. Make configuration structure. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 277 struct rtc_calendar_config config_rtc_calendar; 2. Fill the configuration structure with the default driver configuration. rtc_calendar_get_config_defaults(&config_rtc_calendar); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Make time structure for alarm and set with default and desired values. struct rtc_calendar_time alarm; rtc_calendar_get_time_defaults(&alarm); alarm.year = 2013; alarm.month = 1; alarm.day = 1; alarm.hour = 0; alarm.minute = 0; alarm.second = 4; 4. Change configurations as desired. config_rtc_calendar.clock_24h = true; config_rtc_calendar.alarm[0].time = alarm; config_rtc_calendar.alarm[0].mask = RTC_CALENDAR_ALARM_MASK_YEAR; 5. Initialize module. rtc_calendar_init(&rtc_instance, RTC, &config_rtc_calendar); 6. Enable module. rtc_calendar_enable(&rtc_instance); 13.8.1.3 Implementation Add the following to main(). while (true) { if (rtc_calendar_is_alarm_match(&rtc_instance, RTC_CALENDAR_ALARM_0)) { /* Do something on RTC alarm match here */ port_pin_toggle_output_level(LED_0_PIN); } } rtc_calendar_clear_alarm_match(&rtc_instance, RTC_CALENDAR_ALARM_0); Workflow 1. Start an infinite loop, to continuously poll for a RTC alarm match. while (true) { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 278 2. Check to see if a RTC alarm match has occurred. if (rtc_calendar_is_alarm_match(&rtc_instance, RTC_CALENDAR_ALARM_0)) { 3. Once an alarm match occurs, perform the desired user action. /* Do something on RTC alarm match here */ port_pin_toggle_output_level(LED_0_PIN); 4. Clear the alarm match, so that future alarms may occur. rtc_calendar_clear_alarm_match(&rtc_instance, RTC_CALENDAR_ALARM_0); 13.8.2 Quick Start Guide for RTC (CAL) - Callback In this use case, the RTC is set up in calendar mode. The time is set and an alarm is enabled, as well as a callback for when the alarm time is hit. Each time the callback fires, the alarm time is reset to five seconds in the future and the board LED toggled. 13.8.2.1 Prerequisites The Generic Clock Generator for the RTC should be configured and enabled; if you are using the System Clock driver, this may be done via conf_clocks.h. Clocks and Oscillators The conf_clock.h file needs to be changed with the following values to configure the clocks and oscillators for the module. The following oscillator settings are needed: /* # # # # # # SYSTEM_CLOCK_SOURCE_OSC32K configuration - Internal 32KHz oscillator */ define CONF_CLOCK_OSC32K_ENABLE true define CONF_CLOCK_OSC32K_STARTUP_TIME SYSTEM_OSC32K_STARTUP_130 define CONF_CLOCK_OSC32K_ENABLE_1KHZ_OUTPUT true define CONF_CLOCK_OSC32K_ENABLE_32KHZ_OUTPUT true define CONF_CLOCK_OSC32K_ON_DEMAND true define CONF_CLOCK_OSC32K_RUN_IN_STANDBY false The following generic clock settings are needed: /* # # # # # Configure GCLK generator 2 (RTC) */ define CONF_CLOCK_GCLK_2_ENABLE define CONF_CLOCK_GCLK_2_RUN_IN_STANDBY define CONF_CLOCK_GCLK_2_CLOCK_SOURCE define CONF_CLOCK_GCLK_2_PRESCALER define CONF_CLOCK_GCLK_2_OUTPUT_ENABLE true false SYSTEM_CLOCK_SOURCE_OSC32K 32 false 13.8.2.2 Setup Code Create an rtc_module struct and add to the main application source file, outside of any functions: struct rtc_module rtc_instance; The following must be added to the user application: Function for setting up the module: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 279 void configure_rtc_calendar(void) { /* Initialize RTC in calendar mode. */ struct rtc_calendar_config config_rtc_calendar; rtc_calendar_get_config_defaults(&config_rtc_calendar); alarm.time.year alarm.time.month alarm.time.day alarm.time.hour alarm.time.minute alarm.time.second = = = = = = 2013; 1; 1; 0; 0; 4; config_rtc_calendar.clock_24h = true; config_rtc_calendar.alarm[0].time = alarm.time; config_rtc_calendar.alarm[0].mask = RTC_CALENDAR_ALARM_MASK_YEAR; rtc_calendar_init(&rtc_instance, RTC, &config_rtc_calendar); } rtc_calendar_enable(&rtc_instance); Callback function: void rtc_match_callback(void) { /* Do something on RTC alarm match here */ port_pin_toggle_output_level(LED_0_PIN); /* Set new alarm in 5 seconds */ alarm.mask = RTC_CALENDAR_ALARM_MASK_SEC; alarm.time.second += 5; alarm.time.second = alarm.time.second % 60; } rtc_calendar_set_alarm(&rtc_instance, &alarm, RTC_CALENDAR_ALARM_0); Function for setting up the callback functionality of the driver: void configure_rtc_callbacks(void) { rtc_calendar_register_callback( &rtc_instance, rtc_match_callback, RTC_CALENDAR_CALLBACK_ALARM_0); rtc_calendar_enable_callback(&rtc_instance, RTC_CALENDAR_CALLBACK_ALARM_0); } Add to user application main(): system_init(); struct rtc_calendar_time time; rtc_calendar_get_time_defaults(&time); time.year = 2012; time.month = 12; time.day = 31; time.hour = 23; time.minute = 59; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 280 time.second = 59; /* Configure and enable RTC */ configure_rtc_calendar(); /* Configure and enable callback */ configure_rtc_callbacks(); /* Set current time. */ rtc_calendar_set_time(&rtc_instance, &time); Workflow 1. Initialize system. system_init(); 2. Create and initialize a time structure. struct rtc_calendar_time time; rtc_calendar_get_time_defaults(&time); time.year = 2012; time.month = 12; time.day = 31; time.hour = 23; time.minute = 59; time.second = 59; 3. Configure and enable module. configure_rtc_calendar(); a. Create a RTC configuration structure to hold the desired RTC driver settings and fill it with the default driver configuration values. struct rtc_calendar_config config_rtc_calendar; rtc_calendar_get_config_defaults(&config_rtc_calendar); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. b. Create and initialize an alarm. alarm.time.year alarm.time.month alarm.time.day alarm.time.hour alarm.time.minute alarm.time.second c. = = = = = = 2013; 1; 1; 0; 0; 4; Change settings in the configuration and set alarm. config_rtc_calendar.clock_24h = true; config_rtc_calendar.alarm[0].time = alarm.time; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 281 config_rtc_calendar.alarm[0].mask = RTC_CALENDAR_ALARM_MASK_YEAR; d. Initialize the module with the set configurations. rtc_calendar_init(&rtc_instance, RTC, &config_rtc_calendar); e. Enable the module. rtc_calendar_enable(&rtc_instance); 4. Configure callback functionality. configure_rtc_callbacks(); a. Register overflow callback. rtc_calendar_register_callback( &rtc_instance, rtc_match_callback, RTC_CALENDAR_CALLBACK_ALARM_0); b. Enable overflow callback. rtc_calendar_enable_callback(&rtc_instance, RTC_CALENDAR_CALLBACK_ALARM_0); 5. Set time of the RTC calendar. rtc_calendar_set_time(&rtc_instance, &time); 13.8.2.3 Implementation Code Add to user application main: while (true) { /* Infinite loop */ } Workflow 1. Infinite while loop while waiting for callbacks. while (true) { 13.8.2.4 Callback Each time the RTC time matches the configured alarm, the callback function will be called. Workflow 1. Create alarm struct and initialize the time with current time. struct rtc_calendar_alarm_time alarm; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 282 2. Set alarm to trigger on seconds only. alarm.mask = RTC_CALENDAR_ALARM_MASK_SEC; 3. Add one second to the current time and set new alarm. alarm.time.second += 5; alarm.time.second = alarm.time.second % 60; rtc_calendar_set_alarm(&rtc_instance, &alarm, RTC_CALENDAR_ALARM_0); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 283 14. SAM RTC Count Driver (RTC COUNT) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Real Time Clock functionality in Count operating mode, for the configuration and retrieval of the current RTC counter value. The following driver API modes are covered by this manual: ● Polled APIs The following peripherals are used by this module: ● RTC (Real Time Clock) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 14.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 14.2 Module Overview The RTC module in the SAM devices is a 32-bit counter, with a 10-bit programmable prescaler. Typically, the RTC clock is run continuously, including in the device's low-power sleep modes, to track the current time and date information. The RTC can be used as a source to wake up the system at a scheduled time or periodically using the alarm functions. In this driver, the RTC is operated in Count mode. This allows for an easy integration of an asynchronous counter into a user application, which is capable of operating while the device is in sleep mode. Whilst operating in Count mode, the RTC features: ● ● 16-bit counter mode ● Selectable counter period ● Up to six configurable compare values 32-bit counter mode ● 1 Clear counter value on match http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 284 ● 14.2.1 Driver Feature Macro Definition Driver Feature Macro Supported devices FEATURE_RTC_PERIODIC_INT SAML21 FEATURE_RTC_PRESCALER_OFF SAML21 FEATURE_RTC_CLOCK_SELECTION SAML21 FEATURE_RTC_GENERAL_PURPOSE_REG SAML21 FEATURE_RTC_CONTINUOUSLY_UPDATED SAMD20,SAMD21,SAMR21,SAMD10,SAMD11 Note 14.3 Up to four configurable compare values The specific features are only available in the driver when the selected device supports those features. Compare and Overflow The RTC can be used with up to 4/6 compare values (depending on selected operation mode). These compare values will trigger on match with the current RTC counter value, and can be set up to trigger an interrupt, event, or both. The RTC can also be configured to clear the counter value on compare match in 32-bit mode, resetting the count value back to zero. If the RTC is operated without the Clear on Match option enabled, or in 16-bit mode, the RTC counter value will instead be cleared on overflow once the maximum count value has been reached: (14.1) for 32-bit counter mode, and (14.2) for 16-bit counter mode. When running in 16-bit mode, the overflow value is selectable with a period value. The counter overflow will then occur when the counter value reaches the specified period value. 14.3.1 Periodic Events The RTC can generate events at periodic intervals, allowing for direct peripheral actions without CPU intervention. The periodic events can be generated on the upper eight bits of the RTC prescaler, and will be generated on the rising edge transition of the specified bit. The resulting periodic frequency can be calculated by the following formula: (14.3) Where (14.4) refers to the asynchronous clock set up in the RTC module configuration. The n parameter is the event source generator index of the RTC module. If the asynchronous clock is operated at the recommended frequency of 1KHz, the formula results in the values shown in Table 14-1: RTC Event Frequencies for Each Prescaler Bit Using a 1KHz Clock on page 285. Table 14-1. RTC Event Frequencies for Each Prescaler Bit Using a 1KHz Clock n Periodic event 7 1Hz 6 2Hz 5 4Hz AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 285 n Periodic event 4 8Hz 3 16Hz 2 32Hz 1 64Hz 0 128Hz Note 14.3.2 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Digital Frequency Correction The RTC module contains Digital Frequency Correction logic to compensate for inaccurate source clock frequencies which would otherwise result in skewed time measurements. The correction scheme requires that at least two bits in the RTC module prescaler are reserved by the correction logic. As a result of this implementation, frequency correction is only available when the RTC is running from a 1Hz reference clock. The correction procedure is implemented by subtracting or adding a single cycle from the RTC prescaler every 1024 RTC GCLK cycles. The adjustment is applied the specified number of time (maximum 127) over 976 of these periods. The corresponding correction in PPM will be given by: (14.5) The RTC clock will tick faster if provided with a positive correction value, and slower when given a negative correction value. 14.4 Special Considerations 14.4.1 Clock Setup 14.4.1.1 SAM D20/D21/R21/D10/D11 Clock Setup The RTC is typically clocked by a specialized GCLK generator that has a smaller prescaler than the others. By default the RTC clock is on, selected to use the internal 32KHz RC-oscillator with a prescaler of 32, giving a resulting clock frequency of 1KHz to the RTC. When the internal RTC prescaler is set to 1024, this yields an endfrequency of 1Hz. The implementer also has the option to set other end-frequencies. Table 14-2: RTC Output Frequencies from Allowable Input Clocks on page 286 lists the available RTC frequencies for each possible GCLK and RTC input prescaler options. Table 14-2. RTC Output Frequencies from Allowable Input Clocks End-frequency GCLK prescaler RTC prescaler 32KHz 1 1 1KHz 32 1 1Hz 32 1024 The overall RTC module clocking scheme is shown in Figure 14-1: SAM D20/D21/R21/D10/D11 Clock Setup on page 286. Figure 14-1. SAM D20/D21/R21/D10/D11 Clock Setup GCLK RTC RTC RTC_GCLK RTC P RE S CALE R RTC CLOCK AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 286 14.4.1.2 SAM L21 Clock Setup The RTC clock can be selected from OSC32K,XOSC32K or OSCULP32K , and a 32KHz or 1KHz oscillator clock frequency is required. This clock must be configured and enabled in the 32KHz oscillator controller before using the RTC. The table below lists the available RTC clock Table 14-3: RTC clocks source on page 287 Table 14-3. RTC clocks source 14.5 RTC clock frequency Clock source Description 1.024KHz ULP1K 1.024KHz from 32KHz internal ULP oscillator 32.768KHz ULP32K 32.768KHz from 32KHz internal ULP oscillator 1.024KHz OSC1K 1.024KHz from 32KHz internal oscillator 32.768KHz OSC32K 32.768KHz from 32KHz internal oscillator 1.024KHz XOSC1K 1.024KHz from 32KHz internal oscillator 32.768KHz XOSC32K 32.768KHz from 32KHz external crystal oscillator Extra Information For extra information, see Extra Information for RTC COUNT Driver. This includes: 14.6 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for RTC (COUNT) Driver. 14.7 API Overview 14.7.1 Structure Definitions 14.7.1.1 Struct rtc_count_config Configuration structure for the RTC instance. This structure should be initialized using the rtc_count_get_config_defaults() before any user configurations are set. Table 14-4. Members Type Name Description bool clear_on_match If true, clears the counter value on compare match. Only available whilst running in 32-bit mode. uint32_t compare_values[] Array of Compare values. Not all Compare values are available in 32-bit mode. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 287 Type Name Description bool continuously_update Continuously update the counter value so no synchronization is needed for reading. enum rtc_count_mode mode Select the operation mode of the RTC. enum rtc_count_prescaler prescaler Input clock prescaler for the RTC module. 14.7.1.2 Struct rtc_count_events Event flags for the rtc_count_enable_events() and rtc_count_disable_events(). Table 14-5. Members 14.7.2 Type Name Description bool generate_event_on_compare[] Generate an output event on a compare channel match against the RTC count. bool generate_event_on_overflow Generate an output event on each overflow of the RTC count. bool generate_event_on_periodic[] Generate an output event periodically at a binary division of the RTC counter frequency. Macro Definitions 14.7.2.1 Macro FEATURE_RTC_CONTINUOUSLY_UPDATED #define FEATURE_RTC_CONTINUOUSLY_UPDATED Define port features set according to different device familyRTC continuously updated. 14.7.3 Function Definitions 14.7.3.1 Configuration and Initialization Function rtc_count_get_config_defaults() Gets the RTC default configurations. void rtc_count_get_config_defaults( struct rtc_count_config *const config) Initializes the configuration structure to default values. This function should be called at the start of any RTC initialization. The default configuration is as follows: ● Input clock divided by a factor of 1024 ● RTC in 32-bit mode AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 288 ● Clear on compare match off ● Continuously sync count register off ● No event source on ● All compare values equal 0 Table 14-6. Parameters Data direction Parameter name Description [out] config Configuration structure to be initialized to default values. Function rtc_count_reset() Resets the RTC module. Resets the RTC to hardware defaults. void rtc_count_reset( struct rtc_module *const module) Table 14-7. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function rtc_count_enable() Enables the RTC module. void rtc_count_enable( struct rtc_module *const module) Enables the RTC module once it has been configured, ready for use. Most module configuration parameters cannot be altered while the module is enabled. Table 14-8. Parameters Data direction Parameter name Description [in, out] module RTC hardware module Function rtc_count_disable() Disables the RTC module. void rtc_count_disable( struct rtc_module *const module) Disables the RTC module. Table 14-9. Parameters Data direction Parameter name Description [in, out] module RTC hardware module AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 289 Function rtc_count_init() Initializes the RTC module with given configurations. enum status_code rtc_count_init( struct rtc_module *const module, Rtc *const hw, const struct rtc_count_config *const config) Initializes the module, setting up all given configurations to provide the desired functionality of the RTC. Table 14-10. Parameters Data direction Parameter name Description [out] module Pointer to the software instance struct [in] hw Pointer to hardware instance [in] config Pointer to the configuration structure. Returns Status of the initialization procedure. Table 14-11. Return Values Return value Description STATUS_OK If the initialization was run stressfully. STATUS_ERR_INVALID_ARG If invalid argument(s) were given. Function rtc_count_frequency_correction() Calibrate for too-slow or too-fast oscillator. enum status_code rtc_count_frequency_correction( struct rtc_module *const module, const int8_t value) When used, the RTC will compensate for an inaccurate oscillator. The RTC module will add or subtract cycles from the RTC prescaler to adjust the frequency in approximately 1 PPM steps. The provided correction value should be between 0 and 127, allowing for a maximum 127 PPM correction. If no correction is needed, set value to zero. Note Can only be used when the RTC is operated in 1Hz. Table 14-12. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] value Ranging from -127 to 127 used for the correction. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 290 Returns Status of the calibration procedure. Table 14-13. Return Values Return value Description STATUS_OK If calibration was executed correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. 14.7.3.2 Count and Compare Value Management Function rtc_count_set_count() Set the current count value to desired value. enum status_code rtc_count_set_count( struct rtc_module *const module, const uint32_t count_value) Sets the value of the counter to the specified value. Table 14-14. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] count_value The value to be set in count register. Status of setting the register. Table 14-15. Return Values Return value Description STATUS_OK If everything was executed correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. Function rtc_count_get_count() Get the current count value. uint32_t rtc_count_get_count( struct rtc_module *const module) Table 14-16. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 291 Returns the current count value. Returns The current counter value as a 32-bit unsigned integer. Function rtc_count_set_compare() Set the compare value for the specified compare. enum status_code rtc_count_set_compare( struct rtc_module *const module, const uint32_t comp_value, const enum rtc_count_compare comp_index) Sets the value specified by the implementer to the requested compare. Note Compare 4 and 5 are only available in 16-bit mode. Table 14-17. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] comp_value The value to be written to the compare. [in] comp_index Index of the compare to set. Status indicating if compare was successfully set. Table 14-18. Return Values Return value Description STATUS_OK If compare was successfully set. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. STATUS_ERR_BAD_FORMAT If the module was not initialized in a mode. Function rtc_count_get_compare() Get the current compare value of specified compare. enum status_code rtc_count_get_compare( struct rtc_module *const module, uint32_t *const comp_value, const enum rtc_count_compare comp_index) Retrieves the current value of the specified compare. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 292 Note Compare 4 and 5 are only available in 16-bit mode. Table 14-19. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [out] comp_value Pointer to 32-bit integer that will be populated with the current compare value. [in] comp_index Index of compare to check. Returns Status of the reading procedure. Table 14-20. Return Values Return value Description STATUS_OK If the value was read correctly. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. STATUS_ERR_BAD_FORMAT If the module was not initialized in a mode. Function rtc_count_set_period() Set the given value to the period. enum status_code rtc_count_set_period( struct rtc_module *const module, uint16_t period_value) Sets the given value to the period. Note Only available in 16-bit mode. Table 14-21. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] period_value The value to set to the period. Status of setting the period value. Table 14-22. Return Values Return value Description STATUS_OK If the period was set correctly. STATUS_ERR_UNSUPPORTED_DEV If module is not operated in 16-bit mode. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 293 Function rtc_count_get_period() Retrieves the value of period. enum status_code rtc_count_get_period( struct rtc_module *const module, uint16_t *const period_value) Retrieves the value of the period for the 16-bit mode counter. Note Only available in 16-bit mode. Table 14-23. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [out] period_value Pointer to value for return argument. Returns Status of getting the period value. Table 14-24. Return Values Return value Description STATUS_OK If the period value was read correctly. STATUS_ERR_UNSUPPORTED_DEV If incorrect mode was set. 14.7.3.3 Status Management Function rtc_count_is_overflow() Check if an RTC overflow has occurred. bool rtc_count_is_overflow( struct rtc_module *const module) Checks the overflow flag in the RTC. The flag is set when there is an overflow in the clock. Table 14-25. Parameters Data direction Parameter name Description [in, out] module RTC hardware module Returns Overflow state of the RTC module. Table 14-26. Return Values Return value Description true If the RTC count value has overflowed AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 294 Return value Description false If the RTC count value has not overflowed Function rtc_count_clear_overflow() Clears the RTC overflow flag. void rtc_count_clear_overflow( struct rtc_module *const module) Clears the RTC module counter overflow flag, so that new overflow conditions can be detected. Table 14-27. Parameters Data direction Parameter name Description [in, out] module RTC hardware module Function rtc_count_is_compare_match() Check if RTC compare match has occurred. bool rtc_count_is_compare_match( struct rtc_module *const module, const enum rtc_count_compare comp_index) Checks the compare flag to see if a match has occurred. The compare flag is set when there is a compare match between counter and the compare. Note Compare 4 and 5 are only available in 16-bit mode. Table 14-28. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] comp_index Index of compare to check current flag. Function rtc_count_clear_compare_match() Clears RTC compare match flag. enum status_code rtc_count_clear_compare_match( struct rtc_module *const module, const enum rtc_count_compare comp_index) Clears the compare flag. The compare flag is set when there is a compare match between the counter and the compare. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 295 Note Compare 4 and 5 are only available in 16-bit mode. Table 14-29. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] comp_index Index of compare to check current flag. Returns Status indicating if flag was successfully cleared. Table 14-30. Return Values Return value Description STATUS_OK If flag was successfully cleared. STATUS_ERR_INVALID_ARG If invalid argument(s) were provided. STATUS_ERR_BAD_FORMAT If the module was not initialized in a mode. 14.7.3.4 Event Management Function rtc_count_enable_events() Enables a RTC event output. void rtc_count_enable_events( struct rtc_module *const module, struct rtc_count_events *const events) Enables one or more output events from the RTC module. See rtc_count_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 14-31. Parameters Data direction Parameter name Description [in, out] module RTC hardware module [in] events Struct containing flags of events to enable Function rtc_count_disable_events() Disables a RTC event output. void rtc_count_disable_events( struct rtc_module *const module, struct rtc_count_events *const events) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 296 Disabled one or more output events from the RTC module. See rtc_count_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 14-32. Parameters Data direction Parameter name Description [in, out] module RTC hardware module [in] events Struct containing flags of events to disable 14.7.3.5 Callbacks Function rtc_count_register_callback() Registers callback for the specified callback type. enum status_code rtc_count_register_callback( struct rtc_module *const module, rtc_count_callback_t callback, enum rtc_count_callback callback_type) Associates the given callback function with the specified callback type. To enable the callback, the rtc_count_enable_callback function must be used. Table 14-33. Parameters Returns Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback Pointer to the function desired for the specified callback [in] callback_type Callback type to register Status of registering callback. Table 14-34. Return Values Return value Description STATUS_OK Registering was done successfully STATUS_ERR_INVALID_ARG If trying to register a callback not available Function rtc_count_unregister_callback() Unregisters callback for the specified callback type. enum status_code rtc_count_unregister_callback( struct rtc_module *const module, enum rtc_count_callback callback_type) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 297 When called, the currently registered callback for the given callback type will be removed. Table 14-35. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback_type Specifies the callback type to unregister Returns Status of unregistering callback. Table 14-36. Return Values Return value Description STATUS_OK Unregistering was done successfully STATUS_ERR_INVALID_ARG If trying to unregister a callback not available Function rtc_count_enable_callback() Enables callback. void rtc_count_enable_callback( struct rtc_module *const module, enum rtc_count_callback callback_type) Enables the callback specified by the callback_type. Table 14-37. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback_type Callback type to enable Function rtc_count_disable_callback() Disables callback. void rtc_count_disable_callback( struct rtc_module *const module, enum rtc_count_callback callback_type) Disables the callback specified by the callback_type. Table 14-38. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct [in] callback_type Callback type to disable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 298 14.7.4 Enumeration Definitions 14.7.4.1 Enum rtc_count_callback The available callback types for the RTC count module. Table 14-39. Members Enum value Description RTC_COUNT_CALLBACK_COMPARE_0 Callback for compare channel 0. RTC_COUNT_CALLBACK_COMPARE_1 Callback for compare channel 1. RTC_COUNT_CALLBACK_COMPARE_2 Callback for compare channel 2. RTC_COUNT_CALLBACK_COMPARE_3 Callback for compare channel 3. RTC_COUNT_CALLBACK_COMPARE_4 Callback for compare channel 4. RTC_COUNT_CALLBACK_COMPARE_5 Callback for compare channel 5. RTC_COUNT_CALLBACK_OVERFLOW Callback for overflow. 14.7.4.2 Enum rtc_count_compare Note Not all compare channels are available in all devices and modes. Table 14-40. Members Enum value Description RTC_COUNT_COMPARE_0 Compare channel 0. RTC_COUNT_COMPARE_1 Compare channel 1. RTC_COUNT_COMPARE_2 Compare channel 2. RTC_COUNT_COMPARE_3 Compare channel 3. RTC_COUNT_COMPARE_4 Compare channel 4. RTC_COUNT_COMPARE_5 Compare channel 5. 14.7.4.3 Enum rtc_count_mode RTC Count operating modes, to select the counting width and associated module operation. Table 14-41. Members Enum value Description RTC_COUNT_MODE_16BIT RTC Count module operates in 16-bit mode. RTC_COUNT_MODE_32BIT RTC Count module operates in 32-bit mode. 14.7.4.4 Enum rtc_count_prescaler The available input clock prescaler values for the RTC count module. Table 14-42. Members Enum value Description RTC_COUNT_PRESCALER_DIV_1 RTC input clock frequency is prescaled by a factor of 1. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 299 Enum value Description RTC_COUNT_PRESCALER_DIV_2 RTC input clock frequency is prescaled by a factor of 2. RTC_COUNT_PRESCALER_DIV_4 RTC input clock frequency is prescaled by a factor of 4. RTC_COUNT_PRESCALER_DIV_8 RTC input clock frequency is prescaled by a factor of 8. RTC_COUNT_PRESCALER_DIV_16 RTC input clock frequency is prescaled by a factor of 16. RTC_COUNT_PRESCALER_DIV_32 RTC input clock frequency is prescaled by a factor of 32. RTC_COUNT_PRESCALER_DIV_64 RTC input clock frequency is prescaled by a factor of 64. RTC_COUNT_PRESCALER_DIV_128 RTC input clock frequency is prescaled by a factor of 128. RTC_COUNT_PRESCALER_DIV_256 RTC input clock frequency is prescaled by a factor of 256. RTC_COUNT_PRESCALER_DIV_512 RTC input clock frequency is prescaled by a factor of 512. RTC_COUNT_PRESCALER_DIV_1024 RTC input clock frequency is prescaled by a factor of 1024. 14.8 Extra Information for RTC COUNT Driver 14.8.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 14.8.2 Acronym Description RTC Real Time Counter PPM Part Per Million RC Resistor/Capacitor Dependencies This driver has the following dependencies: ● 14.8.3 None Errata There are no errata related to this driver. 14.8.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAML21 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 300 Changelog Added support for SAMD21 and added driver instance parameter to all API function calls, except get_config_defaults Updated initialization function to also enable the digital interface clock to the module if it is disabled Initial Release 14.9 Examples for RTC (COUNT) Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM RTC Count Driver (RTC COUNT). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_rtc_count_basic_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 301 15. SAM Serial Peripheral Interface Driver (SERCOM SPI) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the SERCOM module in its SPI mode to transfer SPI data frames. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● SERCOM (Serial Communication Interface) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 15.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites. 15.2 Module Overview The Serial Peripheral Interface (SPI) is a high-speed synchronous data transfer interface using three or four pins. It allows fast communication between a master device and one or more peripheral devices. A device connected to the bus must act as a master or a slave. The master initiates and controls all data transactions. The SPI master initiates a communication cycle by pulling low the Slave Select (SS) pin of the desired slave. The Slave Select pin is active low. Master and slave prepare data to be sent in their respective shift registers, and the master generates the required clock pulses on the SCK line to interchange data. Data is always shifted from master to slave on the Master Out - Slave In (MOSI) line, and from slave to master on the Master In Slave Out (MISO) line. After each data transfer, the master can synchronize to the slave by pulling the SS line high. 15.2.1 Driver Feature Macro Definition 1 Driver Feature Macro Supported devices FEATURE_SPI_SLAVE_SELECT_LOW_DETECT SAM D21/R21/D10/D11/L21 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 302 Note 15.2.2 Driver Feature Macro Supported devices FEATURE_SPI_HARDWARE_SLAVE_SELECT SAM D21/R21/D10/D11/L21 FEATURE_SPI_ERROR_INTERRUPT SAM D21/R21/D10/D11/L21 FEATURE_SPI_SYNC_SCHEME_VERSION_2 SAM D21/R21/D10/D11/L21 The specific features are only available in the driver when the selected device supports those features. SPI Bus Connection In Figure 15-1: SPI Bus Connection on page 303, the connection between one master and one slave is shown. Figure 15-1. SPI Bus Connection SPI Ma ster S P I S la ve M OS I M OS I S h ift r e g is t e r S h ift r e g is t e r M IS O M IS O S CK S CK GP IO p in SS The different lines are as follows: ● MISO Master Input Slave Output. The line where the data is shifted out from the slave and in to the master. ● MOSI Master Output Slave Input. The line where the data is shifted out from the master and in to the slave. ● SCK Serial Clock. Generated by the master device. ● SS Slave Select. To initiate a transaction, the master must pull this line low. If the bus consists of several SPI slaves, they can be connected in parallel and the SPI master can use general I/O pins to control separate SS lines to each slave on the bus. It is also possible to connect all slaves in series. In this configuration, a common SS is provided to N slaves, th enabling them simultaneously. The MISO from the N-1 slaves is connected to the MOSI on the next slave. The N slave connects its MISO back to the master. For a complete transaction, the master must shift N+1 characters. 15.2.3 SPI Character Size The SPI character size is configurable to eight or nine bits. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 303 15.2.4 Master Mode When configured as a master, the SS pin will be configured as an output. 15.2.4.1 Data Transfer Writing a character will start the SPI clock generator, and the character is transferred to the shift register when the shift register is empty. Once this is done, a new character can be written. As each character is shifted out from the master, a character is shifted in from the slave. If the receiver is enabled, the data is moved to the receive buffer at the completion of the frame and can be read. 15.2.5 Slave Mode When configured as a slave, the SPI interface will remain inactive with MISO tri-stated as long as the SS pin is driven high. 15.2.5.1 Data Transfer The data register can be updated at any time. As the SPI slave shift register is clocked by SCK, a minimum of three SCK cycles are needed from the time new data is written, until the character is ready to be shifted out. If the shift register has not been loaded with data, the current contents will be transmitted. If constant transmission of data is needed in SPI slave mode, the system clock should be faster than SCK. If the receiver is enabled, the received character can be read from the. When SS line is driven high, the slave will not receive any additional data. 15.2.5.2 Address Recognition When the SPI slave is configured with address recognition, the first character in a transaction is checked for an address match. If there is a match, the MISO output is enabled and the transaction is processed. If the address does not match, the complete transaction is ignored. If the device is asleep, it can be woken up by an address match in order to process the transaction. Note 15.2.6 In master mode, an address packet is written by the spi_select_slave function if the address_enabled configuration is set in the spi_slave_inst_config struct. Data Modes There are four combinations of SCK phase and polarity with respect to serial data. Table 15-1: SPI Data Modes on page 304 shows the clock polarity (CPOL) and clock phase (CPHA) in the different modes. Leading edge is the first clock edge in a clock cycle and trailing edge is the last clock edge in a clock cycle. Table 15-1. SPI Data Modes 15.2.7 Mode CPOL CPHA Leading Edge Trailing Edge 0 0 0 Rising, Sample Falling, Setup 1 0 1 Rising, Setup Falling, Sample 2 1 0 Falling, Sample Rising, Setup 3 1 1 Falling, Setup Rising, Sample SERCOM Pads The SERCOM pads are automatically configured as seen in Table 15-2: SERCOM SPI Pad Usages on page 304. If the receiver is disabled, the data input (MISO for master, MOSI for slave) can be used for other purposes. In master mode, the SS pin(s) must be configured using the spi_slave_inst struct. Table 15-2. SERCOM SPI Pad Usages Pin Master SPI Slave SPI MOSI Output Input AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 304 15.2.8 Pin Master SPI Slave SPI MISO Input Output SCK Output Input SS User defined output enable Input Operation in Sleep Modes The SPI module can operate in all sleep modes by setting the run_in_standby option in the spi_config struct. The operation in slave and master mode is shown in the table below. 15.2.9 run_in_standby Slave Master false Disabled, all reception is dropped GCLK disabled when master is idle, wake on transmit complete true Wake on reception GCLK is enabled while in sleep modes, wake on all interrupts Clock Generation In SPI master mode, the clock (SCK) is generated internally using the SERCOM baudrate generator. In SPI slave mode, the clock is provided by an external master on the SCK pin. This clock is used to directly clock the SPI shift register. 15.3 Special Considerations 15.3.1 pinmux Settings The pin MUX settings must be configured properly, as not all settings can be used in different modes of operation. 15.4 Extra Information For extra information, see Extra Information for SERCOM SPI Driver. This includes: 15.5 ● Acronyms ● Dependencies ● Workarounds Implemented by Driver ● Module History Examples For a list of examples related to this driver, see Examples for SERCOM SPI Driver. 15.6 API Overview 15.6.1 Variable and Type Definitions 15.6.1.1 Type spi_callback_t typedef void(* spi_callback_t )(const struct spi_module *const module) Type of the callback functions. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 305 15.6.2 Structure Definitions 15.6.2.1 Struct spi_config Configuration structure for an SPI instance. This structure should be initialized by the spi_get_config_defaults function before being modified by the user application. Table 15-3. Members Type Name Description enum spi_character_size character_size SPI character size. enum spi_data_order data_order Data order. enum gclk_generator generator_source GCLK generator to use as clock source. bool master_slave_select_enable Enable Master Slave Select. enum spi_mode mode SPI mode. union spi_config.mode_specific mode_specific Union for slave or master specific configuration. enum spi_signal_mux_setting mux_setting MUX setting. uint32_t pinmux_pad0 PAD0 pinmux. uint32_t pinmux_pad1 PAD1 pinmux. uint32_t pinmux_pad2 PAD2 pinmux. uint32_t pinmux_pad3 PAD3 pinmux. bool receiver_enable Enable receiver. bool run_in_standby Enabled in sleep modes. bool select_slave_low_detect_enable Enable Slave Select Low Detect. enum spi_transfer_mode transfer_mode Transfer mode. 15.6.2.2 Union spi_config.mode_specific Union for slave or master specific configuration. Table 15-4. Members Type Name Description struct spi_master_config master Master specific configuration. struct spi_slave_config slave Slave specific configuration. Type Name Description uint32_t baudrate Baud rate. 15.6.2.3 Struct spi_master_config SPI Master configuration structure. Table 15-5. Members 15.6.2.4 Struct spi_module AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 306 SERCOM SPI driver software instance structure, used to retain software state information of an associated hardware module instance. Note The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. 15.6.2.5 Struct spi_slave_config SPI slave configuration structure. Table 15-6. Members Type Name Description uint8_t address Address. uint8_t address_mask Address mask. enum spi_addr_mode address_mode Address mode. enum spi_frame_format frame_format Frame format. bool preload_enable Preload data to the shift register while SS is high. 15.6.2.6 Struct spi_slave_inst SPI peripheral slave software instance structure, used to configure the correct SPI transfer mode settings for an attached slave. See spi_select_slave. Table 15-7. Members Type Name Description uint8_t address Address of slave device. bool address_enabled Address recognition enabled in slave device. uint8_t ss_pin Pin to use as Slave Select. 15.6.2.7 Struct spi_slave_inst_config SPI Peripheral slave configuration structure. Table 15-8. Members 15.6.3 Type Name Description uint8_t address Address of slave. bool address_enabled Enable address. uint8_t ss_pin Pin to use as Slave Select. Macro Definitions 15.6.3.1 Driver Feature Definition Define SERCOM SPI features set according to different device family. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 307 Macro FEATURE_SPI_SLAVE_SELECT_LOW_DETECT #define FEATURE_SPI_SLAVE_SELECT_LOW_DETECT SPI slave select low detection. Macro FEATURE_SPI_HARDWARE_SLAVE_SELECT #define FEATURE_SPI_HARDWARE_SLAVE_SELECT Slave select can be controlled by hardware. Macro FEATURE_SPI_ERROR_INTERRUPT #define FEATURE_SPI_ERROR_INTERRUPT SPI with error detect feature. Macro FEATURE_SPI_SYNC_SCHEME_VERSION_2 #define FEATURE_SPI_SYNC_SCHEME_VERSION_2 SPI sync scheme version 2. 15.6.3.2 Macro PINMUX_DEFAULT #define PINMUX_DEFAULT 0 Default pinmux. 15.6.3.3 Macro PINMUX_UNUSED #define PINMUX_UNUSED 0xFFFFFFFF Unused pinmux. 15.6.3.4 Macro SPI_TIMEOUT #define SPI_TIMEOUT 10000 SPI timeout value. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 308 15.6.4 Function Definitions 15.6.4.1 Driver Initialization and Configuration Function spi_get_config_defaults() Initializes an SPI configuration structure to default values. void spi_get_config_defaults( struct spi_config *const config) This function will initialize a given SPI configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. The default configuration is as follows: ● Master mode enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● MUX Setting D ● Character size eight bits ● Not enabled in sleep mode ● Receiver enabled ● Baudrate 100000 ● Default pinmux settings for all pads ● GCLK generator 0 Table 15-9. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function spi_slave_inst_get_config_defaults() Initializes an SPI peripheral slave device configuration structure to default values. void spi_slave_inst_get_config_defaults( struct spi_slave_inst_config *const config) This function will initialize a given SPI slave device configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. The default configuration is as follows: ● Slave Select on GPIO pin 10 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 309 ● Addressing not enabled Table 15-10. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function spi_attach_slave() Attaches an SPI peripheral slave. void spi_attach_slave( struct spi_slave_inst *const slave, struct spi_slave_inst_config *const config) This function will initialize the software SPI peripheral slave, based on the values of the config struct. The slave can then be selected and optionally addressed by the spi_select_slave function. Table 15-11. Parameters Data direction Parameter name Description [out] slave Pointer to the software slave instance struct [in] config Pointer to the config struct Function spi_init() Initializes the SERCOM SPI module. enum status_code spi_init( struct spi_module *const module, Sercom *const hw, const struct spi_config *const config) This function will initialize the SERCOM SPI module, based on the values of the config struct. Table 15-12. Parameters Returns Data direction Parameter name Description [out] module Pointer to the software instance struct [in] hw Pointer to hardware instance [in] config Pointer to the config struct Status of the initialization. Table 15-13. Return Values Return value Description STATUS_OK Module initiated correctly AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 310 Return value Description STATUS_ERR_DENIED If module is enabled STATUS_BUSY If module is busy resetting STATUS_ERR_INVALID_ARG If invalid argument(s) were provided 15.6.4.2 Enable/Disable Function spi_enable() Enables the SERCOM SPI module. void spi_enable( struct spi_module *const module) This function will enable the SERCOM SPI module. Table 15-14. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function spi_disable() Disables the SERCOM SPI module. void spi_disable( struct spi_module *const module) This function will disable the SERCOM SPI module. Table 15-15. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct Function spi_reset() Resets the SPI module. void spi_reset( struct spi_module *const module) 2 Support and FAQ: visit Atmel Support This function will reset the SPI module to its power on default values and disable it. 2 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 311 Table 15-16. Parameters Data direction Parameter name Description [in, out] module Pointer to the software instance struct 15.6.4.3 Lock/Unlock Function spi_lock() Attempt to get lock on driver instance. enum status_code spi_lock( struct spi_module *const module) This function checks the instance's lock, which indicates whether or not it is currently in use, and sets the lock if it was not already set. The purpose of this is to enable exclusive access to driver instances, so that, e.g., transactions by different services will not interfere with each other. Table 15-17. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 15-18. Return Values Return value Description STATUS_OK if the module was locked STATUS_BUSY if the module was already locked Function spi_unlock() Unlock driver instance. void spi_unlock( struct spi_module *const module) This function clears the instance lock, indicating that it is available for use. Table 15-19. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 15-20. Return Values Return value Description STATUS_OK if the module was locked STATUS_BUSY if the module was already locked AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 312 15.6.4.4 Ready to Write/Read Function spi_is_write_complete() Checks if the SPI in master mode has shifted out last data, or if the master has ended the transfer in slave mode. bool spi_is_write_complete( struct spi_module *const module) This function will check if the SPI master module has shifted out last data, or if the slave select pin has been drawn high by the master for the SPI slave module. Table 15-21. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct Returns Indication of whether any writes are ongoing. Table 15-22. Return Values Return value Description true If the SPI master module has shifted out data, or slave select has been drawn high for SPI slave false If the SPI master module has not shifted out data Function spi_is_ready_to_write() Checks if the SPI module is ready to write data. bool spi_is_ready_to_write( struct spi_module *const module) This function will check if the SPI module is ready to write data. Table 15-23. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct Returns Indication of whether the module is ready to read data or not. Table 15-24. Return Values Return value Description true If the SPI module is ready to write data AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 313 Return value Description false If the SPI module is not ready to write data Function spi_is_ready_to_read() Checks if the SPI module is ready to read data. bool spi_is_ready_to_read( struct spi_module *const module) This function will check if the SPI module is ready to read data. Table 15-25. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct Returns Indication of whether the module is ready to read data or not. Table 15-26. Return Values Return value Description true If the SPI module is ready to read data false If the SPI module is not ready to read data 15.6.4.5 Read/Write Function spi_write() Transfers a single SPI character. enum status_code spi_write( struct spi_module * module, uint16_t tx_data) This function will send a single SPI character via SPI and ignore any data shifted in by the connected device. To both send and receive data, use the spi_transceive_wait function or use the spi_read function after writing a character. The spi_is_ready_to_write function should be called before calling this function. Note that this function does not handle the SS (Slave Select) pin(s) in master mode; this must be handled from the user application. Note In slave mode, the data will not be transferred before a master initiates a transaction. Table 15-27. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 314 Data direction Parameter name Description [in] tx_data Data to transmit Returns Status of the procedure. Table 15-28. Return Values Return value Description STATUS_OK If the data was written STATUS_BUSY If the last write was not completed Function spi_write_buffer_wait() Sends a buffer of length SPI characters. enum status_code spi_write_buffer_wait( struct spi_module *const module, const uint8_t * tx_data, uint16_t length) This function will send a buffer of SPI characters via the SPI and discard any data that is received. To both send and receive a buffer of data, use the spi_transceive_buffer_wait function. Note that this function does not handle the _SS (slave select) pin(s) in master mode; this must be handled by the user application. Table 15-29. Parameters Returns Data direction Parameter name Description [in] module Pointer to the software instance struct [in] tx_data Pointer to the buffer to transmit [in] length Number of SPI characters to transfer Status of the write operation. Table 15-30. Return Values Return value Description STATUS_OK If the write was completed STATUS_ABORTED If transaction was ended by master before entire buffer was transferred STATUS_ERR_INVALID_ARG If invalid argument(s) were provided STATUS_ERR_TIMEOUT If the operation was not completed within the timeout in slave mode Function spi_read() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 315 Reads last received SPI character. enum status_code spi_read( struct spi_module *const module, uint16_t * rx_data) This function will return the last SPI character shifted into the receive register by the spi_write function. Note The spi_is_ready_to_read function should be called before calling this function. Receiver must be enabled in the configuration. Table 15-31. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct [out] rx_data Pointer to store the received data Returns Status of the read operation. Table 15-32. Return Values Return value Description STATUS_OK If data was read STATUS_ERR_IO If no data is available STATUS_ERR_OVERFLOW If the data is overflown Function spi_read_buffer_wait() Reads buffer of length SPI characters. enum status_code spi_read_buffer_wait( struct spi_module *const module, uint8_t * rx_data, uint16_t length, uint16_t dummy) This function will read a buffer of data from an SPI peripheral by sending dummy SPI character if in master mode, or by waiting for data in slave mode. Note If address matching is enabled for the slave, the first character received and placed in the buffer will be the address. Table 15-33. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 316 Data direction Parameter name Description [out] rx_data Data buffer for received data [in] length Length of data to receive [in] dummy 8- or 9-bit dummy byte to shift out in master mode Returns Status of the read operation. Table 15-34. Return Values Return value Description STATUS_OK If the read was completed STATUS_ABORTED If transaction was ended by master before entire buffer was transferred STATUS_ERR_INVALID_ARG If invalid argument(s) were provided STATUS_ERR_TIMEOUT If the operation was not completed within the timeout in slave mode STATUS_ERR_DENIED If the receiver is not enabled STATUS_ERR_OVERFLOW If the data is overflown Function spi_transceive_wait() Sends and reads a single SPI character. enum status_code spi_transceive_wait( struct spi_module *const module, uint16_t tx_data, uint16_t * rx_data) This function will transfer a single SPI character via SPI and return the SPI character that is shifted into the shift register. In master mode the SPI character will be sent immediately and the received SPI character will be read as soon as the shifting of the data is complete. In slave mode this function will place the data to be sent into the transmit buffer. It will then block until an SPI master has shifted a complete SPI character, and the received data is available. Note The data to be sent might not be sent before the next transfer, as loading of the shift register is dependent on SCK. If address matching is enabled for the slave, the first character received and placed in the buffer will be the address. Table 15-35. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct [in] tx_data SPI character to transmit AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 317 Data direction Parameter name Description [out] rx_data Pointer to store the received SPI character Returns Status of the operation. Table 15-36. Return Values Return value Description STATUS_OK If the operation was completed STATUS_ERR_TIMEOUT If the operation was not completed within the timeout in slave mode STATUS_ERR_DENIED If the receiver is not enabled STATUS_ERR_OVERFLOW If the incoming data is overflown Function spi_transceive_buffer_wait() Sends and receives a buffer of length SPI characters. enum status_code spi_transceive_buffer_wait( struct spi_module *const module, uint8_t * tx_data, uint8_t * rx_data, uint16_t length) This function will send and receive a buffer of data via the SPI. In master mode the SPI characters will be sent immediately and the received SPI character will be read as soon as the shifting of the SPI character is complete. In slave mode this function will place the data to be sent into the transmit buffer. It will then block until an SPI master has shifted the complete buffer and the received data is available. Table 15-37. Parameters Returns Data direction Parameter name Description [in] module Pointer to the software instance struct [in] tx_data Pointer to the buffer to transmit [out] rx_data Pointer to the buffer where received data will be stored [in] length Number of SPI characters to transfer Status of the operation. Table 15-38. Return Values Return value Description STATUS_OK If the operation was completed STATUS_ERR_INVALID_ARG If invalid argument(s) were provided AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 318 Return value Description STATUS_ERR_TIMEOUT If the operation was not completed within the timeout in slave mode STATUS_ERR_DENIED If the receiver is not enabled STATUS_ERR_OVERFLOW If the data is overflown Function spi_select_slave() Selects slave device. enum status_code spi_select_slave( struct spi_module *const module, struct spi_slave_inst *const slave, bool select) This function will drive the slave select pin of the selected device low or high depending on the select Boolean. If slave address recognition is enabled, the address will be sent to the slave when selecting it. Table 15-39. Parameters Returns Data direction Parameter name Description [in] module Pointer to the software module struct [in] slave Pointer to the attached slave [in] select Boolean stating if the slave should be selected or deselected Status of the operation. Table 15-40. Return Values Return value Description STATUS_OK If the slave device was selected STATUS_ERR_UNSUPPORTED_DEV If the SPI module is operating in slave mode STATUS_BUSY If the SPI module is not ready to write the slave address 15.6.4.6 Callback Management Function spi_register_callback() Registers a SPI callback function. void spi_register_callback( struct spi_module *const module, spi_callback_t callback_func, enum spi_callback callback_type) Registers a callback function which is implemented by the user. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 319 Note The callback must be enabled by spi_enable_callback, in order for the interrupt handler to call it when the conditions for the callback type are met. Table 15-41. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] callback_func Pointer to callback function [in] callback_type Callback type given by an enum Function spi_unregister_callback() Unregisters a SPI callback function. void spi_unregister_callback( struct spi_module * module, enum spi_callback callback_type) Unregisters a callback function which is implemented by the user. Table 15-42. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct [in] callback_type Callback type given by an enum Function spi_enable_callback() Enables a SPI callback of a given type. void spi_enable_callback( struct spi_module *const module, enum spi_callback callback_type) Enables the callback function registered by the spi_register_callback. The callback function will be called from the interrupt handler when the conditions for the callback type are met. Table 15-43. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct [in] callback_type Callback type given by an enum Function spi_disable_callback() Disables callback. void spi_disable_callback( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 320 struct spi_module *const module, enum spi_callback callback_type) Disables the callback function registered by the spi_register_callback, and the callback will not be called from the interrupt routine. Table 15-44. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct [in] callback_type Callback type given by an enum 15.6.4.7 Writing and Reading Function spi_write_buffer_job() Asynchronous buffer write. enum status_code spi_write_buffer_job( struct spi_module *const module, uint8_t * tx_data, uint16_t length) Sets up the driver to write to the SPI from a given buffer. If registered and enabled, a callback function will be called when the write is finished. Table 15-45. Parameters Returns Data direction Parameter name Description [in] module Pointer to USART software instance struct [out] tx_data Pointer to data buffer to receive [in] length Data buffer length Status of the write request operation. Table 15-46. Return Values Return value Description STATUS_OK If the operation completed successfully STATUS_ERR_BUSY If the SPI was already busy with a write operation STATUS_ERR_INVALID_ARG If requested write length was zero Function spi_read_buffer_job() Asynchronous buffer read. enum status_code spi_read_buffer_job( struct spi_module *const module, uint8_t * rx_data, uint16_t length, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 321 uint16_t dummy) Sets up the driver to read from the SPI to a given buffer. If registered and enabled, a callback function will be called when the read is finished. Note If address matching is enabled for the slave, the first character received and placed in the RX buffer will be the address. Table 15-47. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct [out] rx_data Pointer to data buffer to receive [in] length Data buffer length [in] dummy Dummy character to send when reading in master mode Returns Status of the operation. Table 15-48. Return Values Return value Description STATUS_OK If the operation completed successfully STATUS_ERR_BUSY If the SPI was already busy with a read operation STATUS_ERR_DENIED If the receiver is not enabled STATUS_ERR_INVALID_ARG If requested read length was zero Function spi_transceive_buffer_job() Asynchronous buffer write and read. enum status_code spi_transceive_buffer_job( struct spi_module *const module, uint8_t * tx_data, uint8_t * rx_data, uint16_t length) Sets up the driver to write and read to and from given buffers. If registered and enabled, a callback function will be called when the transfer is finished. Note If address matching is enabled for the slave, the first character received and placed in the RX buffer will be the address. Table 15-49. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 322 Data direction Parameter name Description [in] tx_data Pointer to data buffer to send [out] rx_data Pointer to data buffer to receive [in] length Data buffer length Returns Status of the operation. Table 15-50. Return Values Return value Description STATUS_OK If the operation completed successfully STATUS_ERR_BUSY If the SPI was already busy with a read operation STATUS_ERR_DENIED If the receiver is not enabled STATUS_ERR_INVALID_ARG If requested read length was zero Function spi_abort_job() Aborts an ongoing job. void spi_abort_job( struct spi_module *const module) This function will abort the specified job type. Table 15-51. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct Function spi_get_job_status() Retrieves the current status of a job. enum status_code spi_get_job_status( const struct spi_module *const module) Retrieves the current statue of a job that was previously issued. Table 15-52. Parameters Returns Data direction Parameter name Description [in] module Pointer to SPI software instance struct Current job status. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 323 Function spi_get_job_status_wait() Retrieves the status of job once it ends. enum status_code spi_get_job_status_wait( const struct spi_module *const module) Waits for current job status to become non-busy, then returns its value. Table 15-53. Parameters Data direction Parameter name Description [in] module Pointer to SPI software instance struct Returns Current non-busy job status. 15.6.4.8 Function spi_is_syncing() Determines if the SPI module is currently synchronizing to the bus. bool spi_is_syncing( struct spi_module *const module) This function will check if the underlying hardware peripheral module is currently synchronizing across multiple clock domains to the hardware bus. This function can be used to delay further operations on the module until it is ready. Table 15-54. Parameters Data direction Parameter name Description [in] module SPI hardware module Returns Synchronization status of the underlying hardware module. Table 15-55. Return Values Return value Description true Module synchronization is ongoing false Module synchronization is not ongoing 15.6.4.9 Function spi_set_baudrate() Set the baudrate of the SPI module. enum status_code spi_set_baudrate( struct spi_module *const module, uint32_t baudrate) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 324 This function will set the baudrate of the SPI module. Table 15-56. Parameters Returns Data direction Parameter name Description [in] module Pointer to the software instance struct [in] baudrate The baudrate wanted The status of the configuration. Table 15-57. Return Values 15.6.5 Return value Description STATUS_ERR_INVALID_ARG If invalid argument(s) were provided STATUS_OK If the configuration was written Enumeration Definitions 15.6.5.1 Enum spi_addr_mode For slave mode when using the SPI frame with address format. Table 15-58. Members Enum value Description SPI_ADDR_MODE_MASK address_mask in the spi_config struct is used as a mask to the register. SPI_ADDR_MODE_UNIQUE The slave responds to the two unique addresses in address and address_mask in the spi_config struct. SPI_ADDR_MODE_RANGE The slave responds to the range of addresses between and including address and address_mask in in the spi_config struct. 15.6.5.2 Enum spi_callback Callbacks for SPI callback driver. Note For slave mode, these callbacks will be called when a transaction is ended by the master pulling Slave Select high. Table 15-59. Members Enum value Description SPI_CALLBACK_BUFFER_TRANSMITTED Callback for buffer transmitted. SPI_CALLBACK_BUFFER_RECEIVED Callback for buffer received. SPI_CALLBACK_BUFFER_TRANSCEIVED Callback for buffers transceived. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 325 Enum value Description SPI_CALLBACK_ERROR Callback for error. SPI_CALLBACK_SLAVE_TRANSMISSION_COMPLETE Callback for transmission ended by master before entire buffer was read or written from slave. SPI_CALLBACK_SLAVE_SELECT_LOW Callback for slave select low. SPI_CALLBACK_COMBINED_ERROR Callback for combined error happen. 15.6.5.3 Enum spi_character_size SPI character size. Table 15-60. Members Enum value Description SPI_CHARACTER_SIZE_8BIT 8-bit character. SPI_CHARACTER_SIZE_9BIT 9-bit character. 15.6.5.4 Enum spi_data_order SPI data order. Table 15-61. Members Enum value Description SPI_DATA_ORDER_LSB The LSB of the data is transmitted first. SPI_DATA_ORDER_MSB The MSB of the data is transmitted first. 15.6.5.5 Enum spi_frame_format Frame format for slave mode. Table 15-62. Members Enum value Description SPI_FRAME_FORMAT_SPI_FRAME SPI frame. SPI_FRAME_FORMAT_SPI_FRAME_ADDR SPI frame with address. 15.6.5.6 Enum spi_interrupt_flag Interrupt flags for the SPI module. Table 15-63. Members Enum value Description SPI_INTERRUPT_FLAG_DATA_REGISTER_EMPTY This flag is set when the contents of the data register has been moved to the shift register and the data register is ready for new data. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 326 Enum value Description SPI_INTERRUPT_FLAG_TX_COMPLETE This flag is set when the contents of the shift register has been shifted out. SPI_INTERRUPT_FLAG_RX_COMPLETE This flag is set when data has been shifted into the data register. SPI_INTERRUPT_FLAG_SLAVE_SELECT_LOW This flag is set when slave select low. SPI_INTERRUPT_FLAG_COMBINED_ERROR This flag is set when combined error happen. 15.6.5.7 Enum spi_mode SPI mode selection. Table 15-64. Members Enum value Description SPI_MODE_MASTER Master mode. SPI_MODE_SLAVE Slave mode. 15.6.5.8 Enum spi_signal_mux_setting Set the functionality of the SERCOM pins. As not all settings can be used in different modes of operation, proper settings must be chosen according to the rest of the configuration. See MUX Settings for a description of the various MUX setting options. Table 15-65. Members Enum value Description SPI_SIGNAL_MUX_SETTING_A SPI MUX setting A. SPI_SIGNAL_MUX_SETTING_B SPI MUX setting B. SPI_SIGNAL_MUX_SETTING_C SPI MUX setting C. SPI_SIGNAL_MUX_SETTING_D SPI MUX setting D. SPI_SIGNAL_MUX_SETTING_E SPI MUX setting E. SPI_SIGNAL_MUX_SETTING_F SPI MUX setting F. SPI_SIGNAL_MUX_SETTING_G SPI MUX setting G. SPI_SIGNAL_MUX_SETTING_H SPI MUX setting H. SPI_SIGNAL_MUX_SETTING_I SPI MUX setting I. SPI_SIGNAL_MUX_SETTING_J SPI MUX setting J. SPI_SIGNAL_MUX_SETTING_K SPI MUX setting K. SPI_SIGNAL_MUX_SETTING_L SPI MUX setting L. SPI_SIGNAL_MUX_SETTING_M SPI MUX setting M. SPI_SIGNAL_MUX_SETTING_N SPI MUX setting N. SPI_SIGNAL_MUX_SETTING_O SPI MUX setting O. SPI_SIGNAL_MUX_SETTING_P SPI MUX setting P. 15.6.5.9 Enum spi_transfer_mode AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 327 SPI transfer mode. Table 15-66. Members 15.7 Enum value Description SPI_TRANSFER_MODE_0 Mode 0. Leading edge: rising, sample. Trailing edge: falling, setup. SPI_TRANSFER_MODE_1 Mode 1. Leading edge: rising, setup. Trailing edge: falling, sample. SPI_TRANSFER_MODE_2 Mode 2. Leading edge: falling, sample. Trailing edge: rising, setup. SPI_TRANSFER_MODE_3 Mode 3. Leading edge: falling, setup. Trailing edge: rising, sample. MUX Settings The following lists the possible internal SERCOM module pad function assignments, for the four SERCOM pads in both SPI Master, and SPI Slave modes. Note that this is in addition to the physical GPIO pin MUX of the device, and can be used in conjunction to optimize the serial data pin-out. 15.7.1 Master Mode Settings The following table describes the SERCOM pin functionalities for the various MUX settings, whilst in SPI Master mode. Note If MISO is unlisted, the SPI receiver must not be enabled for the given MUX setting. MUX/Pad PAD 0 PAD 1 PAD 2 PAD 3 A MOSI SCK - - B MOSI SCK - - C MOSI SCK MISO - D MOSI SCK - MISO E MISO - MOSI SCK F - MISO MOSI SCK G - - MOSI SCK H - - MOSI SCK I (1) MISO SCK - MOSI J (1) - SCK - MOSI K (1) - SCK MISO MOSI L (1) - SCK - MOSI M (1) MOSI - - SCK N (1) MOSI MISO - SCK O (1) MOSI - MISO SCK P (1) MOSI - - SCK (1) Not available in all silicon revisions. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 328 15.7.2 Slave Mode Settings The following table describes the SERCOM pin functionalities for the various MUX settings, whilst in SPI Slave mode. Note If MISO is unlisted, the SPI receiver must not be enabled for the given MUX setting. MUX/Pad PAD 0 PAD 1 PAD 2 PAD 3 A MISO SCK /SS - B MISO SCK /SS - C MISO SCK /SS - D MISO SCK /SS MOSI E MOSI /SS MISO SCK F - /SS MISO SCK G - /SS MISO SCK H - /SS MISO SCK I (1) MOSI SCK /SS MISO J (1) - SCK /SS MISO K (1) - SCK /SS MISO L (1) - SCK /SS MISO M (1) MISO /SS - SCK N (1) MISO /SS - SCK O (1) MISO /SS MOSI SCK P (1) MISO /SS - SCK (1) Not available in all silicon revisions. 15.8 Extra Information for SERCOM SPI Driver 15.8.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. Acronym Description SERCOM Serial Communication Interface SPI Serial Peripheral Interface SCK Serial Clock MOSI Master Output Slave Input MISO Master Input Slave Output SS Slave Select DIO Data Input Output DO Data Output DI Data Input DMA Direct Memory Access AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 329 15.8.2 Dependencies The SPI driver has the following dependencies: ● 15.8.3 System Pin Multiplexer Driver Workarounds Implemented by Driver No workarounds in driver. 15.8.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add SAML21 support Add SAMD21 support and added new features as below: ● Slave select low detect ● Hardware slave select ● DMA support Edited slave part of write and transceive buffer functions to ensure that second character is sent at the right time Renamed the anonymous union in struct spi_config to mode_specific Initial Release 15.9 Examples for SERCOM SPI Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Serial Peripheral Interface Driver (SERCOM SPI). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 15.9.1 ● Quick Start Guide for SERCOM SPI Master - Polled ● Quick Start Guide for SERCOM SPI Slave - Polled ● Quick Start Guide for SERCOM SPI Master - Callback ● Quick Start Guide for SERCOM SPI Slave - Callback ● Quick Start Guide for Using DMA with SERCOM SPI Quick Start Guide for SERCOM SPI Master - Polled In this use case, the SPI on extension header 1 of the Xplained Pro board will configured with the following settings: ● Master Mode enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size ● Not enabled in sleep mode AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 330 ● Baudrate 100000 ● GLCK generator 0 15.9.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code The following must be added to the user application: A sample buffer to send via SPI. static const uint8_t buffer[BUF_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13 }; Number of entries in the sample buffer. #define BUF_LENGTH 20 GPIO pin to use as Slave Select. #define SLAVE_SELECT_PIN EXT1_PIN_SPI_SS_0 A globally available software device instance struct to store the SPI driver state while it is in use. struct spi_module spi_master_instance; A globally available peripheral slave software device instance struct. struct spi_slave_inst slave; A function for configuring the SPI. void configure_spi_master(void) { struct spi_config config_spi_master; struct spi_slave_inst_config slave_dev_config; /* Configure and initialize software device instance of peripheral slave */ spi_slave_inst_get_config_defaults(&slave_dev_config); slave_dev_config.ss_pin = SLAVE_SELECT_PIN; spi_attach_slave(&slave, &slave_dev_config); /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_master); config_spi_master.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_master.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_master.pinmux_pad1 = PINMUX_UNUSED; /* Configure pad 2 for data out */ config_spi_master.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; /* Configure pad 3 for SCK */ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 331 config_spi_master.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; spi_init(&spi_master_instance, EXT1_SPI_MODULE, &config_spi_master); spi_enable(&spi_master_instance); } Add to user application main(). system_init(); configure_spi_master(); 15.9.1.2 Workflow 1. Initialize system. system_init(); 2. Setup the SPI. configure_spi_master(); a. Create configuration struct. struct spi_config config_spi_master; b. Create peripheral slave configuration struct. struct spi_slave_inst_config slave_dev_config; c. Create peripheral slave software device instance struct. struct spi_slave_inst slave; d. Get default peripheral slave configuration. spi_slave_inst_get_config_defaults(&slave_dev_config); e. Set Slave Select pin. slave_dev_config.ss_pin = SLAVE_SELECT_PIN; f. Initialize peripheral slave software instance with configuration. spi_attach_slave(&slave, &slave_dev_config); g. Get default configuration to edit. spi_get_config_defaults(&config_spi_master); h. Set MUX setting E. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 332 config_spi_master.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; i. Set pinmux for pad 0 (data in (MISO)). config_spi_master.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; j. Set pinmux for pad 1 as unused, so the pin can be used for other purposes. config_spi_master.pinmux_pad1 = PINMUX_UNUSED; k. Set pinmux for pad 2 (data out (MOSI)). config_spi_master.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; l. Set pinmux for pad 3 (SCK). config_spi_master.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; m. Initialize SPI module with configuration. spi_init(&spi_master_instance, EXT1_SPI_MODULE, &config_spi_master); n. Enable SPI module. spi_enable(&spi_master_instance); 15.9.1.3 Use Case Code Add the following to your user application main(). spi_select_slave(&spi_master_instance, &slave, true); spi_write_buffer_wait(&spi_master_instance, buffer, BUF_LENGTH); spi_select_slave(&spi_master_instance, &slave, false); while (true) { /* Infinite loop */ } Workflow 1. Select slave. spi_select_slave(&spi_master_instance, &slave, true); 2. Write buffer to SPI slave. spi_write_buffer_wait(&spi_master_instance, buffer, BUF_LENGTH); 3. Deselect slave. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 333 spi_select_slave(&spi_master_instance, &slave, false); 4. Infinite loop. while (true) { /* Infinite loop */ } 15.9.2 Quick Start Guide for SERCOM SPI Slave - Polled In this use case, the SPI on extension header 1 of the Xplained Pro board will configured with the following settings: ● Slave mode enabled ● Preloading of shift register enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size ● Not enabled in sleep mode ● GLCK generator 0 15.9.2.1 Setup Prerequisites The device must be connected to a SPI master which must read from the device. Code The following must be added to the user application source file, outside any functions: A sample buffer to send via SPI. static const uint8_t buffer[BUF_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13 }; Number of entries in the sample buffer. #define BUF_LENGTH 20 A globally available software device instance struct to store the SPI driver state while it is in use. struct spi_module spi_slave_instance; A function for configuring the SPI. void configure_spi_slave(void) { struct spi_config config_spi_slave; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 334 /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_slave); config_spi_slave.mode = SPI_MODE_SLAVE; config_spi_slave.mode_specific.slave.preload_enable = true; config_spi_slave.mode_specific.slave.frame_format = SPI_FRAME_FORMAT_SPI_FRAME; config_spi_slave.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_slave.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_slave.pinmux_pad1 = EXT1_SPI_SERCOM_PINMUX_PAD1; /* Configure pad 2 for data out */ config_spi_slave.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; /* Configure pad 3 for SCK */ config_spi_slave.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; spi_init(&spi_slave_instance, EXT1_SPI_MODULE, &config_spi_slave); spi_enable(&spi_slave_instance); } Add to user application main(). /* Initialize system */ system_init(); configure_spi_slave(); Workflow 1. Initialize system. system_init(); 2. Setup the SPI. configure_spi_slave(); a. Create configuration struct. struct spi_config config_spi_slave; b. Get default configuration to edit. spi_get_config_defaults(&config_spi_slave); c. Set the SPI in slave mode. config_spi_slave.mode = SPI_MODE_SLAVE; d. Enable preloading of shift register. config_spi_slave.mode_specific.slave.preload_enable = true; e. Set frame format to SPI frame. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 335 config_spi_slave.mode_specific.slave.frame_format = SPI_FRAME_FORMAT_SPI_FRAME; f. Set MUX setting E. config_spi_slave.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; g. Set pinmux for pad 0 (data in (MOSI)). config_spi_slave.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; h. Set pinmux for pad 1 (slave select). config_spi_slave.pinmux_pad1 = EXT1_SPI_SERCOM_PINMUX_PAD1; i. Set pinmux for pad 2 (data out (MISO)). config_spi_slave.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; j. Set pinmux for pad 3 (SCK). config_spi_slave.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; k. Initialize SPI module with configuration. spi_init(&spi_slave_instance, EXT1_SPI_MODULE, &config_spi_slave); l. Enable SPI module. spi_enable(&spi_slave_instance); 15.9.2.2 Use Case Code Add the following to your user application main(). while (spi_write_buffer_wait(&spi_slave_instance, buffer, BUF_LENGTH) != STATUS_OK) { /* Wait for transfer from master */ } while (true) { /* Infinite loop */ } Workflow 1. Write buffer to SPI master. Placed in a loop to retry in case of a timeout before a master initiates a transaction. while (spi_write_buffer_wait(&spi_slave_instance, buffer, BUF_LENGTH) != STATUS_OK) { /* Wait for transfer from master */ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 336 } 2. Infinite loop. while (true) { /* Infinite loop */ } 15.9.3 Quick Start Guide for SERCOM SPI Master - Callback In this use case, the SPI on extension header 1 of the Xplained Pro board will configured with the following settings: ● Master Mode enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size ● Not enabled in sleep mode ● Baudrate 100000 ● GLCK generator 0 15.9.3.1 Setup Prerequisites There are no special setup requirements for this use-case. Code The following must be added to the user application. A sample buffer to send via SPI. static uint8_t wr_buffer[BUF_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13 }; static uint8_t rd_buffer[BUF_LENGTH]; Number of entries in the sample buffer. #define BUF_LENGTH 20 GPIO pin to use as Slave Select. #define SLAVE_SELECT_PIN EXT1_PIN_SPI_SS_0 A globally available software device instance struct to store the SPI driver state while it is in use. struct spi_module spi_master_instance; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 337 A globally available peripheral slave software device instance struct. struct spi_slave_inst slave; A function for configuring the SPI. void configure_spi_master(void) { struct spi_config config_spi_master; struct spi_slave_inst_config slave_dev_config; /* Configure and initialize software device instance of peripheral slave */ spi_slave_inst_get_config_defaults(&slave_dev_config); slave_dev_config.ss_pin = SLAVE_SELECT_PIN; spi_attach_slave(&slave, &slave_dev_config); /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_master); config_spi_master.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_master.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_master.pinmux_pad1 = PINMUX_UNUSED; /* Configure pad 2 for data out */ config_spi_master.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; /* Configure pad 3 for SCK */ config_spi_master.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; spi_init(&spi_master_instance, EXT1_SPI_MODULE, &config_spi_master); spi_enable(&spi_master_instance); } A function for configuring the callback functionality of the SPI. void configure_spi_master_callbacks(void) { spi_register_callback(&spi_master_instance, callback_spi_master, SPI_CALLBACK_BUFFER_TRANSCEIVED); spi_enable_callback(&spi_master_instance, SPI_CALLBACK_BUFFER_TRANSCEIVED); } A global variable that can flag to the application that the buffer has been transferred. volatile bool transrev_complete_spi_master = false; Callback function. static void callback_spi_master(const struct spi_module *const module) { transrev_complete_spi_master = true; } Add to user application main(). /* Initialize system */ system_init(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 338 configure_spi_master(); configure_spi_master_callbacks(); 15.9.3.2 Workflow 1. Initialize system. system_init(); 2. Setup the SPI. configure_spi_master(); a. Create configuration struct. struct spi_config config_spi_master; b. Create peripheral slave configuration struct. struct spi_slave_inst_config slave_dev_config; c. Get default peripheral slave configuration. spi_slave_inst_get_config_defaults(&slave_dev_config); d. Set Slave Select pin. slave_dev_config.ss_pin = SLAVE_SELECT_PIN; e. Initialize peripheral slave software instance with configuration. spi_attach_slave(&slave, &slave_dev_config); f. Get default configuration to edit. spi_get_config_defaults(&config_spi_master); g. Set MUX setting E. config_spi_master.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; h. Set pinmux for pad 0 (data in (MISO)). config_spi_master.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; i. Set pinmux for pad 1 as unused, so the pin can be used for other purposes. config_spi_master.pinmux_pad1 = PINMUX_UNUSED; j. Set pinmux for pad 2 (data out (MOSI)). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 339 config_spi_master.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; k. Set pinmux for pad 3 (SCK). config_spi_master.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; l. Initialize SPI module with configuration. spi_init(&spi_master_instance, EXT1_SPI_MODULE, &config_spi_master); m. Enable SPI module. spi_enable(&spi_master_instance); 3. Setup the callback functionality. configure_spi_master_callbacks(); a. Register callback function for buffer transmitted. spi_register_callback(&spi_master_instance, callback_spi_master, SPI_CALLBACK_BUFFER_TRANSCEIVED); b. Enable callback for buffer transmitted. spi_enable_callback(&spi_master_instance, SPI_CALLBACK_BUFFER_TRANSCEIVED); 15.9.3.3 Use Case Code Add the following to your user application main(). while (true) { /* Infinite loop */ if (!port_pin_get_input_level(BUTTON_0_PIN)) { spi_select_slave(&spi_master_instance, &slave, true); spi_transceive_buffer_job(&spi_master_instance, wr_buffer,rd_buffer,BUF_LENGTH); while (!transrev_complete_spi_master) { } spi_select_slave(&spi_master_instance, &slave, false); } } Workflow 1. Select slave. spi_select_slave(&spi_master_instance, &slave, true); 2. Write buffer to SPI slave. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 340 spi_transceive_buffer_job(&spi_master_instance, wr_buffer,rd_buffer,BUF_LENGTH); 3. Wait for the transfer to be complete. while (!transrev_complete_spi_master) { } 4. Deselect slave. spi_select_slave(&spi_master_instance, &slave, false); 5. Infinite loop. while (true) { /* Infinite loop */ if (!port_pin_get_input_level(BUTTON_0_PIN)) { spi_select_slave(&spi_master_instance, &slave, true); spi_transceive_buffer_job(&spi_master_instance, wr_buffer,rd_buffer,BUF_LENGTH); while (!transrev_complete_spi_master) { } spi_select_slave(&spi_master_instance, &slave, false); } } 15.9.3.4 Callback When the buffer is successfully transmitted to the slave, the callback function will be called. Workflow 1. Let the application know that the buffer is transmitted by setting the global variable to true. transrev_complete_spi_master = true; 15.9.4 Quick Start Guide for SERCOM SPI Slave - Callback In this use case, the SPI on extension header 1 of the Xplained Pro board will configured with the following settings: ● Slave mode enabled ● Preloading of shift register enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size ● Not enabled in sleep mode ● GLCK generator 0 15.9.4.1 Setup Prerequisites The device must be connected to a SPI master which must read from the device. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 341 Code The following must be added to the user application source file, outside any functions. A sample buffer to send via SPI. static uint8_t buffer[BUF_LENGTH] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13 }; Number of entries in the sample buffer. #define BUF_LENGTH 20 A globally available software device instance struct to store the SPI driver state while it is in use. struct spi_module spi_slave_instance; A function for configuring the SPI. void configure_spi_slave(void) { struct spi_config config_spi_slave; /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_slave); config_spi_slave.mode = SPI_MODE_SLAVE; config_spi_slave.mode_specific.slave.preload_enable = true; config_spi_slave.mode_specific.slave.frame_format = SPI_FRAME_FORMAT_SPI_FRAME; config_spi_slave.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_slave.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_slave.pinmux_pad1 = EXT1_SPI_SERCOM_PINMUX_PAD1; /* Configure pad 2 for data out */ config_spi_slave.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; /* Configure pad 3 for SCK */ config_spi_slave.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; spi_init(&spi_slave_instance, EXT1_SPI_MODULE, &config_spi_slave); spi_enable(&spi_slave_instance); } A function for configuring the callback functionality of the SPI. void configure_spi_slave_callbacks(void) { spi_register_callback(&spi_slave_instance, spi_slave_callback, SPI_CALLBACK_BUFFER_TRANSMITTED); spi_enable_callback(&spi_slave_instance, SPI_CALLBACK_BUFFER_TRANSMITTED); } A global variable that can flag to the application that the buffer has been transferred. volatile bool transfer_complete_spi_slave = false; Callback function. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 342 static void spi_slave_callback(const struct spi_module *const module) { transfer_complete_spi_slave = true; } Add to user application main(). /* Initialize system */ system_init(); configure_spi_slave(); configure_spi_slave_callbacks(); Workflow 1. Initialize system. system_init(); 2. Setup the SPI. configure_spi_slave(); a. Create configuration struct. struct spi_config config_spi_slave; b. Get default configuration to edit. spi_get_config_defaults(&config_spi_slave); c. Set the SPI in slave mode. config_spi_slave.mode = SPI_MODE_SLAVE; d. Enable preloading of shift register. config_spi_slave.mode_specific.slave.preload_enable = true; e. Set frame format to SPI frame. config_spi_slave.mode_specific.slave.frame_format = SPI_FRAME_FORMAT_SPI_FRAME; f. Set MUX setting E. config_spi_slave.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING; g. Set pinmux for pad 0 (data in (MOSI)). config_spi_slave.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 343 h. Set pinmux for pad 1 (slave select). config_spi_slave.pinmux_pad1 = EXT1_SPI_SERCOM_PINMUX_PAD1; i. Set pinmux for pad 2 (data out (MISO)). config_spi_slave.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2; j. Set pinmux for pad 3 (SCK). config_spi_slave.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3; k. Initialize SPI module with configuration. spi_init(&spi_slave_instance, EXT1_SPI_MODULE, &config_spi_slave); l. Enable SPI module. spi_enable(&spi_slave_instance); 3. Setup the callback functionality. configure_spi_slave_callbacks(); a. Register callback function for buffer transmitted. spi_register_callback(&spi_slave_instance, spi_slave_callback, SPI_CALLBACK_BUFFER_TRANSMITTED); b. Enable callback for buffer transmitted. spi_enable_callback(&spi_slave_instance, SPI_CALLBACK_BUFFER_TRANSMITTED); 15.9.4.2 Use Case Code Add the following to your user application main(). spi_write_buffer_job(&spi_slave_instance, buffer, BUF_LENGTH); while(!transfer_complete_spi_slave) { /* Wait for transfer from master */ } while (true) { /* Infinite loop */ } Workflow 1. Initiate a write buffer job. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 344 spi_write_buffer_job(&spi_slave_instance, buffer, BUF_LENGTH); 2. Wait for the transfer to be complete. while(!transfer_complete_spi_slave) { /* Wait for transfer from master */ } 3. Infinite loop. while (true) { /* Infinite loop */ } 15.9.4.3 Callback When the buffer is successfully transmitted to the master, the callback function will be called. Workflow 1. Let the application know that the buffer is transmitted by setting the global variable to true. transfer_complete_spi_slave = true; 15.9.5 Quick Start Guide for Using DMA with SERCOM SPI The supported board list: ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAML21 Xplained Pro This quick start will transmit a buffer data from master to slave through DMA. In this use case the SPI master will be configured with the following settings on SAM Xplained Pro: ● Master Mode enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size ● Not enabled in sleep mode ● Baudrate 100000 ● GLCK generator 0 The SPI slave will be configured with the following settings: ● Slave mode enabled ● Preloading of shift register enabled ● MSB of the data is transmitted first ● Transfer mode 0 ● 8-bit character size AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 345 ● Not enabled in sleep mode ● GLCK generator 0 Note that the pinouts on other boards may different, see next sector for details. 15.9.5.1 Setup Prerequisites The following connections has to be made using wires: ● ● ● SAM D21 Xplained Pro. ● SS_0: EXT1 PIN15 (PA05) <> EXT2 PIN15 (PA17) ● DO/DI: EXT1 PIN16 (PA06) <> EXT2 PIN17 (PA16) ● DI/DO: EXT1 PIN17 (PA04) <> EXT2 PIN16 (PA18) ● SCK: EXT1 PIN18 (PA07) <> EXT2 PIN18 (PA19) SAM R21 Xplained Pro. ● SS_0: EXT1 PIN15 (PB03) <> EXT1 PIN10 (PA23) ● DO/DI: EXT1 PIN16 (PB22) <> EXT1 PIN9 (PA22) ● DI/DO: EXT1 PIN17 (PB02) <> EXT1 PIN7 (PA18) ● SCK: EXT1 PIN18 (PB23) <> EXT1 PIN8 (PA19) SAM L21 Xplained Pro. ● SS_0: EXT1 PIN15 (PA05) <> EXT1 PIN12 (PA09) ● DO/DI: EXT1 PIN16 (PA06) <> EXT1 PIN11 (PA08) ● DI/DO: EXT1 PIN17 (PA04) <> EXT2 PIN03 (PA10) ● SCK: EXT1 PIN18 (PA07) <> EXT2 PIN04 (PA11) Code Add to the main application source file, before user definitions and functions according to your board: For SAMD21 Xplained Pro: #define #define #define #define #define #define #define CONF_MASTER_SPI_MODULE CONF_MASTER_SS_PIN CONF_MASTER_MUX_SETTING CONF_MASTER_PINMUX_PAD0 CONF_MASTER_PINMUX_PAD1 CONF_MASTER_PINMUX_PAD2 CONF_MASTER_PINMUX_PAD3 #define #define #define #define #define #define CONF_SLAVE_SPI_MODULE CONF_SLAVE_MUX_SETTING CONF_SLAVE_PINMUX_PAD0 CONF_SLAVE_PINMUX_PAD1 CONF_SLAVE_PINMUX_PAD2 CONF_SLAVE_PINMUX_PAD3 EXT2_SPI_MODULE EXT2_PIN_SPI_SS_0 EXT2_SPI_SERCOM_MUX_SETTING EXT2_SPI_SERCOM_PINMUX_PAD0 PINMUX_UNUSED EXT2_SPI_SERCOM_PINMUX_PAD2 EXT2_SPI_SERCOM_PINMUX_PAD3 EXT1_SPI_MODULE EXT1_SPI_SERCOM_MUX_SETTING EXT1_SPI_SERCOM_PINMUX_PAD0 EXT1_SPI_SERCOM_PINMUX_PAD1 EXT1_SPI_SERCOM_PINMUX_PAD2 EXT1_SPI_SERCOM_PINMUX_PAD3 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 346 #define CONF_PERIPHERAL_TRIGGER_TX #define CONF_PERIPHERAL_TRIGGER_RX SERCOM1_DMAC_ID_TX SERCOM0_DMAC_ID_RX For SAMR21 Xplained Pro: #define #define #define #define #define #define #define CONF_MASTER_SPI_MODULE CONF_MASTER_SS_PIN CONF_MASTER_MUX_SETTING CONF_MASTER_PINMUX_PAD0 CONF_MASTER_PINMUX_PAD1 CONF_MASTER_PINMUX_PAD2 CONF_MASTER_PINMUX_PAD3 #define #define #define #define #define #define CONF_SLAVE_SPI_MODULE CONF_SLAVE_MUX_SETTING CONF_SLAVE_PINMUX_PAD0 CONF_SLAVE_PINMUX_PAD1 CONF_SLAVE_PINMUX_PAD2 CONF_SLAVE_PINMUX_PAD3 SERCOM3 EXT1_PIN_10 SPI_SIGNAL_MUX_SETTING_E PINMUX_PA22C_SERCOM3_PAD0 PINMUX_UNUSED PINMUX_PA18D_SERCOM3_PAD2 PINMUX_PA19D_SERCOM3_PAD3 EXT1_SPI_MODULE EXT1_SPI_SERCOM_MUX_SETTING EXT1_SPI_SERCOM_PINMUX_PAD0 EXT1_SPI_SERCOM_PINMUX_PAD1 EXT1_SPI_SERCOM_PINMUX_PAD2 EXT1_SPI_SERCOM_PINMUX_PAD3 #define CONF_PERIPHERAL_TRIGGER_TX #define CONF_PERIPHERAL_TRIGGER_RX SERCOM3_DMAC_ID_TX SERCOM5_DMAC_ID_RX For SAML21 Xplained Pro: #define #define #define #define #define #define #define CONF_MASTER_SPI_MODULE CONF_MASTER_SS_PIN CONF_MASTER_MUX_SETTING CONF_MASTER_PINMUX_PAD0 CONF_MASTER_PINMUX_PAD1 CONF_MASTER_PINMUX_PAD2 CONF_MASTER_PINMUX_PAD3 #define #define #define #define #define #define CONF_SLAVE_SPI_MODULE CONF_SLAVE_MUX_SETTING CONF_SLAVE_PINMUX_PAD0 CONF_SLAVE_PINMUX_PAD1 CONF_SLAVE_PINMUX_PAD2 CONF_SLAVE_PINMUX_PAD3 SERCOM2 EXT1_PIN_12 SPI_SIGNAL_MUX_SETTING_E PINMUX_PA08D_SERCOM2_PAD0 PINMUX_UNUSED PINMUX_PA10D_SERCOM2_PAD2 PINMUX_PA11D_SERCOM2_PAD3 EXT1_SPI_MODULE EXT1_SPI_SERCOM_MUX_SETTING EXT1_SPI_SERCOM_PINMUX_PAD0 EXT1_SPI_SERCOM_PINMUX_PAD1 EXT1_SPI_SERCOM_PINMUX_PAD2 EXT1_SPI_SERCOM_PINMUX_PAD3 #define CONF_PERIPHERAL_TRIGGER_TX #define CONF_PERIPHERAL_TRIGGER_RX SERCOM2_DMAC_ID_TX SERCOM0_DMAC_ID_RX Add to the main application source file, outside of any functions: #define BUF_LENGTH 20 #define TEST_SPI_BAUDRATE 1000000UL #define SLAVE_SELECT_PIN CONF_MASTER_SS_PIN static const uint8_t buffer_tx[BUF_LENGTH] = { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 347 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, }; static uint8_t buffer_rx[BUF_LENGTH]; struct spi_module spi_master_instance; struct spi_module spi_slave_instance; static volatile bool transfer_tx_is_done = false; static volatile bool transfer_rx_is_done = false; struct spi_slave_inst slave; COMPILER_ALIGNED(16) DmacDescriptor example_descriptor_tx; DmacDescriptor example_descriptor_rx; Copy-paste the following setup code to your user application: static void transfer_tx_done( const struct dma_resource* const resource ) { transfer_tx_is_done = true; } static void transfer_rx_done( const struct dma_resource* const resource ) { transfer_rx_is_done = true; } static void configure_dma_resource_tx(struct dma_resource *tx_resource) { struct dma_resource_config tx_config; dma_get_config_defaults(&tx_config); tx_config.peripheral_trigger = CONF_PERIPHERAL_TRIGGER_TX; tx_config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } dma_allocate(tx_resource, &tx_config); static void configure_dma_resource_rx(struct dma_resource *rx_resource) { struct dma_resource_config rx_config; dma_get_config_defaults(&rx_config); rx_config.peripheral_trigger = CONF_PERIPHERAL_TRIGGER_RX; rx_config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } dma_allocate(rx_resource, &rx_config); static void setup_transfer_descriptor_tx(DmacDescriptor *tx_descriptor) { struct dma_descriptor_config tx_descriptor_config; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 348 dma_descriptor_get_config_defaults(&tx_descriptor_config); tx_descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; tx_descriptor_config.dst_increment_enable = false; tx_descriptor_config.block_transfer_count = sizeof(buffer_tx)/sizeof(uint8_t); tx_descriptor_config.source_address = (uint32_t)buffer_tx + sizeof(buffer_tx); tx_descriptor_config.destination_address = (uint32_t)(&spi_master_instance.hw->SPI.DATA.reg); } dma_descriptor_create(tx_descriptor, &tx_descriptor_config); static void setup_transfer_descriptor_rx(DmacDescriptor *rx_descriptor) { struct dma_descriptor_config rx_descriptor_config; dma_descriptor_get_config_defaults(&rx_descriptor_config); rx_descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; rx_descriptor_config.src_increment_enable = false; rx_descriptor_config.block_transfer_count = sizeof(buffer_rx)/sizeof(uint8_t); rx_descriptor_config.source_address = (uint32_t)(&spi_slave_instance.hw->SPI.DATA.reg); rx_descriptor_config.destination_address = (uint32_t)buffer_rx + sizeof(buffer_rx); } dma_descriptor_create(rx_descriptor, &rx_descriptor_config); static void configure_spi_master(void) { struct spi_config config_spi_master; struct spi_slave_inst_config slave_dev_config; /* Configure and initialize software device instance of peripheral slave */ spi_slave_inst_get_config_defaults(&slave_dev_config); slave_dev_config.ss_pin = SLAVE_SELECT_PIN; spi_attach_slave(&slave, &slave_dev_config); /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_master); config_spi_master.mode_specific.master.baudrate = TEST_SPI_BAUDRATE; config_spi_master.mux_setting = CONF_MASTER_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_master.pinmux_pad0 = CONF_MASTER_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_master.pinmux_pad1 = CONF_MASTER_PINMUX_PAD1; /* Configure pad 2 for data out */ config_spi_master.pinmux_pad2 = CONF_MASTER_PINMUX_PAD2; /* Configure pad 3 for SCK */ config_spi_master.pinmux_pad3 = CONF_MASTER_PINMUX_PAD3; spi_init(&spi_master_instance, CONF_MASTER_SPI_MODULE, &config_spi_master); spi_enable(&spi_master_instance); } static void configure_spi_slave(void) { struct spi_config config_spi_slave; /* Configure, initialize and enable SERCOM SPI module */ spi_get_config_defaults(&config_spi_slave); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 349 config_spi_slave.mode = SPI_MODE_SLAVE; config_spi_slave.mode_specific.slave.preload_enable = true; config_spi_slave.mode_specific.slave.frame_format = SPI_FRAME_FORMAT_SPI_FRAME; config_spi_slave.mux_setting = CONF_SLAVE_MUX_SETTING; /* Configure pad 0 for data in */ config_spi_slave.pinmux_pad0 = CONF_SLAVE_PINMUX_PAD0; /* Configure pad 1 as unused */ config_spi_slave.pinmux_pad1 = CONF_SLAVE_PINMUX_PAD1; /* Configure pad 2 for data out */ config_spi_slave.pinmux_pad2 = CONF_SLAVE_PINMUX_PAD2; /* Configure pad 3 for SCK */ config_spi_slave.pinmux_pad3 = CONF_SLAVE_PINMUX_PAD3; spi_init(&spi_slave_instance, CONF_SLAVE_SPI_MODULE, &config_spi_slave); spi_enable(&spi_slave_instance); } Add to user application initialization (typically the start of main()): configure_spi_master(); configure_spi_slave(); configure_dma_resource_tx(&example_resource_tx); configure_dma_resource_rx(&example_resource_rx); setup_transfer_descriptor_tx(&example_descriptor_tx); setup_transfer_descriptor_rx(&example_descriptor_rx); dma_add_descriptor(&example_resource_tx, &example_descriptor_tx); dma_add_descriptor(&example_resource_rx, &example_descriptor_rx); dma_register_callback(&example_resource_tx, transfer_tx_done, DMA_CALLBACK_TRANSFER_DONE); dma_register_callback(&example_resource_rx, transfer_rx_done, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&example_resource_tx, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&example_resource_rx, DMA_CALLBACK_TRANSFER_DONE); Workflow 1. Create a module software instance structure for the SPI module to store the SPI driver state while it is in use. struct spi_module spi_master_instance; struct spi_module spi_slave_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Create a module software instance structure for DMA resource to store the DMA resource state while it is in use. struct dma_resource example_resource_tx; struct dma_resource example_resource_rx; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 350 Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 3. Create transfer done flag to indication DMA transfer done. static volatile bool transfer_tx_is_done = false; static volatile bool transfer_rx_is_done = false; 4. Define the buffer length for TX/RX. #define BUF_LENGTH 20 5. Create buffer to store the data to be transferred. static const uint8_t buffer_tx[BUF_LENGTH] = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, }; static uint8_t buffer_rx[BUF_LENGTH]; 6. Create SPI module configuration struct, which can be filled out to adjust the configuration of a physical SPI peripheral. struct spi_config config_spi_master; struct spi_config config_spi_slave; 7. Initialize the SPI configuration struct with the module's default values. spi_get_config_defaults(&config_spi_master); spi_get_config_defaults(&config_spi_slave); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 8. Alter the SPI settings to configure the physical pinout, baudrate and other relevant parameters. config_spi_master.mux_setting = CONF_MASTER_MUX_SETTING; config_spi_slave.mux_setting = CONF_SLAVE_MUX_SETTING; 9. Configure the SPI module with the desired settings, retrying while the driver is busy until the configuration is stressfully set. spi_init(&spi_master_instance, CONF_MASTER_SPI_MODULE, &config_spi_master); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 351 spi_init(&spi_slave_instance, CONF_SLAVE_SPI_MODULE, &config_spi_slave); 10. Enable the SPI module. spi_enable(&spi_master_instance); spi_enable(&spi_slave_instance); 11. Create DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config tx_config; struct dma_resource_config rx_config; 12. Initialize the DMA resource configuration struct with the module's default values. dma_get_config_defaults(&tx_config); dma_get_config_defaults(&rx_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 13. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM TX empty and RX complete trigger causes a beat transfer in this example. tx_config.peripheral_trigger = CONF_PERIPHERAL_TRIGGER_TX; tx_config.trigger_action = DMA_TRIGGER_ACTON_BEAT; rx_config.peripheral_trigger = CONF_PERIPHERAL_TRIGGER_RX; rx_config.trigger_action = DMA_TRIGGER_ACTON_BEAT; 14. Allocate a DMA resource with the configurations. dma_allocate(tx_resource, &tx_config); dma_allocate(rx_resource, &rx_config); 15. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config tx_descriptor_config; struct dma_descriptor_config rx_descriptor_config; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 352 16. Initialize the DMA transfer descriptor configuration struct with the module's default values. dma_descriptor_get_config_defaults(&tx_descriptor_config); dma_descriptor_get_config_defaults(&rx_descriptor_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 17. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. tx_descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; tx_descriptor_config.dst_increment_enable = false; tx_descriptor_config.block_transfer_count = sizeof(buffer_tx)/sizeof(uint8_t); tx_descriptor_config.source_address = (uint32_t)buffer_tx + sizeof(buffer_tx); tx_descriptor_config.destination_address = (uint32_t)(&spi_master_instance.hw->SPI.DATA.reg); rx_descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE; rx_descriptor_config.src_increment_enable = false; rx_descriptor_config.block_transfer_count = sizeof(buffer_rx)/sizeof(uint8_t); rx_descriptor_config.source_address = (uint32_t)(&spi_slave_instance.hw->SPI.DATA.reg); rx_descriptor_config.destination_address = (uint32_t)buffer_rx + sizeof(buffer_rx); 18. Create the DMA transfer descriptor. dma_descriptor_create(tx_descriptor, &tx_descriptor_config); dma_descriptor_create(rx_descriptor, &rx_descriptor_config); 15.9.5.2 Use Case Code Copy-paste the following code to your user application: spi_select_slave(&spi_master_instance, &slave, true); dma_start_transfer_job(&example_resource_rx); dma_start_transfer_job(&example_resource_tx); while (!transfer_rx_is_done) { /* Wait for transfer done */ } spi_select_slave(&spi_master_instance, &slave, false); while (true) { } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 353 Workflow 1. Select the slave. spi_select_slave(&spi_master_instance, &slave, true); 2. Start the transfer job. dma_start_transfer_job(&example_resource_rx); dma_start_transfer_job(&example_resource_tx); 3. Wait for transfer done. while (!transfer_rx_is_done) { /* Wait for transfer done */ } 4. Deselect the slave. spi_select_slave(&spi_master_instance, &slave, false); 5. Enter endless loop. while (true) { } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 354 16. SAM Serial USART Driver (SERCOM USART) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the SERCOM module in its USART mode to transfer or receive USART data frames. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● SERCOM (Serial Communication Interface) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 16.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites To use the USART you need to have a GCLK generator enabled and running that can be used as the SERCOM clock source. This can either be configured in conf_clocks.h or by using the system clock driver. 16.2 Module Overview This driver will use one (or more) SERCOM interfaces on the system and configure it to run as a USART interface in either synchronous or asynchronous mode. 16.2.1 Driver Feature Macro Definition 1 Driver Feature Macro Supported devices FEATURE_USART_SYNC_SCHEME_V2 SAM D21/R21/D10/D11/L21 FEATURE_USART_OVER_SAMPLE SAM D21/R21/D10/D11/L21 FEATURE_USART_HARDWARE_FLOW_CONTROL SAM D21/R21/D10/D11/L21 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 355 Driver Feature Macro Supported devices FEATURE_USART_IRDA SAM D21/R21/D10/D11/L21 FEATURE_USART_LIN_SLAVE SAM D21/R21/D10/D11/L21 FEATURE_USART_COLLISION_DECTION SAM D21/R21/D10/D11/L21 FEATURE_USART_START_FRAME_DECTION SAM D21/R21/D10/D11/L21 FEATURE_USART_IMMEDIATE_BUFFER_OVERFLOW_NOTIFICATION SAM D21/R21/D10/D11/L21 Note 16.2.2 The specific features are only available in the driver when the selected device supports those features. Frame Format Communication is based on frames, where the frame format can be customized to accommodate a wide range of standards. A frame consists of a start bit, a number of data bits, an optional parity bit for error detection as well as a configurable length stop bit(s) - see Figure 16-1: USART Frame Overview on page 356. Table 16-1: USART Frame Parameters on page 356 shows the available parameters you can change in a frame. Table 16-1. USART Frame Parameters Parameter Options Start bit 1 Data bits 5, 6, 7, 8, 9 Parity bit None, Even, Odd Stop bits 1, 2 Figure 16-1. USART Frame Overview Frame (IDLE) 16.2.3 St 0 1 2 3 4 [5] [6] [7] [8] [P] Sp1 [Sp2] (St/IDLE) Synchronous Mode In synchronous mode a dedicated clock line is provided; either by the USART itself if in master mode, or by an external master if in slave mode. Maximum transmission speed is the same as the GCLK clocking the USART peripheral when in slave mode, and the GCLK divided by two if in master mode. In synchronous mode the interface needs three lines to communicate: ● TX (Transmit pin) ● RX (Receive pin) ● XCK (Clock pin) 16.2.3.1 Data Sampling In synchronous mode the data is sampled on either the rising or falling edge of the clock signal. This is configured by setting the clock polarity in the configuration struct. 16.2.4 Asynchronous Mode In asynchronous mode no dedicated clock line is used, and the communication is based on matching the clock speed on the transmitter and receiver. The clock is generated from the internal SERCOM baudrate generator, and AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 356 the frames are synchronized by using the frame start bits. Maximum transmission speed is limited to the SERCOM GCLK divided by 16. In asynchronous mode the interface only needs two lines to communicate: ● TX (Transmit pin) ● RX (Receive pin) 16.2.4.1 Transmitter/receiver Clock Matching For successful transmit and receive using the asynchronous mode the receiver and transmitter clocks needs to be closely matched. When receiving a frame that does not match the selected baudrate closely enough the receiver will be unable to synchronize the frame(s), and garbage transmissions will result. 16.2.5 Parity Parity can be enabled to detect if a transmission was in error. This is done by counting the number of "1" bits in the frame. When using Even parity the parity bit will be set if the total number of "1"s in the frame are an even number. If using Odd parity the parity bit will be set if the total number of "1"s are Odd. When receiving a character the receiver will count the number of "1"s in the frame and give an error if the received frame and parity bit disagree. 16.2.6 GPIO Configuration The SERCOM module has four internal pads; the RX pin can be placed freely on any one of the four pads, and the TX and XCK pins have two predefined positions that can be selected as a pair. The pads can then be routed to an external GPIO pin using the normal pin multiplexing scheme on the SAM. 16.3 Special Considerations Never execute large portions of code in the callbacks. These are run from the interrupt routine, and thus having long callbacks will keep the processor in the interrupt handler for an equally long time. A common way to handle this is to use global flags signaling the main application that an interrupt event has happened, and only do the minimal needed processing in the callback. 16.4 Extra Information For extra information, see Extra Information for SERCOM USART Driver. This includes: 16.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for SERCOM USART Driver. 16.6 API Overview 16.6.1 Variable and Type Definitions 16.6.1.1 Type usart_callback_t typedef void(* usart_callback_t )(const struct usart_module *const module) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 357 Type of the callback functions. 16.6.2 Structure Definitions 16.6.2.1 Struct usart_config Configuration options for USART. Table 16-2. Members Type Name Description uint32_t baudrate USART baudrate. enum usart_character_size character_size USART character size. bool clock_polarity_inverted USART Clock Polarity. If true, data changes on falling XCK edge and is sampled at rising edge. If false, data changes on rising XCK edge and is sampled at falling edge. enum usart_dataorder data_order USART bit order (MSB or LSB first). uint32_t ext_clock_freq External clock frequency in synchronous mode. This must be set if use_external_clock is true. enum gclk_generator generator_source GCLK generator source. enum usart_signal_mux_settings mux_setting USART pin out. enum usart_parity parity USART parity. uint32_t pinmux_pad0 PAD0 pinmux. uint32_t pinmux_pad1 PAD1 pinmux. uint32_t pinmux_pad2 PAD2 pinmux. uint32_t pinmux_pad3 PAD3 pinmux. bool receiver_enable Enable receiver. bool run_in_standby If true the USART will be kept running in Standby sleep mode. enum usart_stopbits stopbits Number of stop bits. enum usart_transfer_mode transfer_mode USART in asynchronous or synchronous mode. bool transmitter_enable Enable transmitter. bool use_external_clock States whether to use the external clock applied to the XCK pin. In synchronous mode the shift register will act directly on the XCK clock. In asynchronous mode the XCK will be the input to the USART hardware module. 16.6.2.2 Struct usart_module SERCOM USART driver software instance structure, used to retain software state information of an associated hardware module instance. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 358 Note 16.6.3 The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. Macro Definitions 16.6.3.1 Macro PINMUX_DEFAULT #define PINMUX_DEFAULT 0 Default pinmux. 16.6.3.2 Macro PINMUX_UNUSED #define PINMUX_UNUSED 0xFFFFFFFF Unused pinmux. 16.6.3.3 Macro USART_TIMEOUT #define USART_TIMEOUT 0xFFFF USART timeout value. 16.6.4 Function Definitions 16.6.4.1 Lock/Unlock Function usart_lock() Attempt to get lock on driver instance. enum status_code usart_lock( struct usart_module *const module) This function checks the instance's lock, which indicates whether or not it is currently in use, and sets the lock if it was not already set. The purpose of this is to enable exclusive access to driver instances, so that, e.g., transactions by different services will not interfere with each other. Table 16-3. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock Table 16-4. Return Values Return value Description STATUS_OK If the module was locked AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 359 Return value Description STATUS_BUSY If the module was already locked Function usart_unlock() Unlock driver instance. void usart_unlock( struct usart_module *const module) This function clears the instance lock, indicating that it is available for use. Table 16-5. Parameters Data direction Parameter name Description [in, out] module Pointer to the driver instance to lock 16.6.4.2 Writing and Reading Function usart_write_wait() Transmit a character via the USART. enum status_code usart_write_wait( struct usart_module *const module, const uint16_t tx_data) This blocking function will transmit a single character via the USART. Table 16-6. Parameters Returns Data direction Parameter name Description [in] module Pointer to the software instance struct [in] tx_data Data to transfer Status of the operation. Table 16-7. Return Values Return value Description STATUS_OK If the operation was completed STATUS_BUSY If the operation was not completed, due to the USART module being busy STATUS_ERR_DENIED If the transmitter is not enabled Function usart_read_wait() Receive a character via the USART. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 360 enum status_code usart_read_wait( struct usart_module *const module, uint16_t *const rx_data) This blocking function will receive a character via the USART. Table 16-8. Parameters Data direction Parameter name Description [in] module Pointer to the software instance struct [out] rx_data Pointer to received data Returns Status of the operation. Table 16-9. Return Values Return value Description STATUS_OK If the operation was completed STATUS_BUSY If the operation was not completed, due to the USART module being busy STATUS_ERR_BAD_FORMAT If the operation was not completed, due to configuration mismatch between USART and the sender STATUS_ERR_BAD_OVERFLOW If the operation was not completed, due to the baudrate being too low or the system frequency being too high STATUS_ERR_BAD_DATA If the operation was not completed, due to data being corrupted STATUS_ERR_DENIED If the receiver is not enabled Function usart_write_buffer_wait() Transmit a buffer of characters via the USART. enum status_code usart_write_buffer_wait( struct usart_module *const module, const uint8_t * tx_data, uint16_t length) This blocking function will transmit a block of length characters via the USART. Note Using this function in combination with the interrupt (_job) functions is not recommended as it has no functionality to check if there is an ongoing interrupt driven operation running or not. Table 16-10. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 361 Data direction Parameter name Description [in] tx_data Pointer to data to transmit [in] length Number of characters to transmit Note if using 9-bit data, the array that *tx_data point to should be defined as uint16_t array and should be casted to uint8_t* pointer. Because it is an address pointer, the highest byte is not discarded. For example: #define TX_LEN 3 uint16_t tx_buf[TX_LEN] = {0x0111, 0x0022, 0x0133}; usart_write_buffer_wait(&module, (uint8_t*)tx_buf, TX_LEN); Returns Status of the operation. Table 16-11. Return Values Return value Description STATUS_OK If operation was completed STATUS_ERR_INVALID_ARG If operation was not completed, due to invalid arguments STATUS_ERR_TIMEOUT If operation was not completed, due to USART module timing out STATUS_ERR_DENIED If the transmitter is not enabled Function usart_read_buffer_wait() Receive a buffer of length characters via the USART. enum status_code usart_read_buffer_wait( struct usart_module *const module, uint8_t * rx_data, uint16_t length) This blocking function will receive a block of length characters via the USART. Note Using this function in combination with the interrupt (*_job) functions is not recommended as it has no functionality to check if there is an ongoing interrupt driven operation running or not. Table 16-12. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [out] rx_data Pointer to receive buffer [in] length Number of characters to receive AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 362 Note if using 9-bit data, the array that *rx_data point to should be defined as uint16_t array and should be casted to uint8_t* pointer. Because it is an address pointer, the highest byte is not discarded. For example: #define RX_LEN 3 uint16_t rx_buf[RX_LEN] = {0x0,}; usart_read_buffer_wait(&module, (uint8_t*)rx_buf, RX_LEN); Returns Status of the operation. Table 16-13. Return Values Return value Description STATUS_OK If operation was completed STATUS_ERR_INVALID_ARG If operation was not completed, due to an invalid argument being supplied STATUS_ERR_TIMEOUT If operation was not completed, due to USART module timing out STATUS_ERR_BAD_FORMAT If the operation was not completed, due to a configuration mismatch between USART and the sender STATUS_ERR_BAD_OVERFLOW If the operation was not completed, due to the baudrate being too low or the system frequency being too high STATUS_ERR_BAD_DATA If the operation was not completed, due to data being corrupted STATUS_ERR_DENIED If the receiver is not enabled 16.6.4.3 Enabling/Disabling Receiver and Transmitter Function usart_enable_transceiver() Enable Transceiver. void usart_enable_transceiver( struct usart_module *const module, enum usart_transceiver_type transceiver_type) Enable the given transceiver. Either RX or TX. Table 16-14. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] transceiver_type Transceiver type Function usart_disable_transceiver() Disable Transceiver. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 363 void usart_disable_transceiver( struct usart_module *const module, enum usart_transceiver_type transceiver_type) Disable the given transceiver (RX or TX). Table 16-15. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] transceiver_type Transceiver type 16.6.4.4 Callback Management Function usart_register_callback() Registers a callback. void usart_register_callback( struct usart_module *const module, usart_callback_t callback_func, enum usart_callback callback_type) Registers a callback function which is implemented by the user. Note The callback must be enabled by usart_enable_callback, in order for the interrupt handler to call it when the conditions for the callback type are met. Table 16-16. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] callback_func Pointer to callback function [in] callback_type Callback type given by an enum Function usart_unregister_callback() Unregisters a callback. void usart_unregister_callback( struct usart_module * module, enum usart_callback callback_type) Unregisters a callback function which is implemented by the user. Table 16-17. Parameters Data direction Parameter name Description [in, out] module Pointer to USART software instance struct [in] callback_type Callback type given by an enum AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 364 Function usart_enable_callback() Enables callback. void usart_enable_callback( struct usart_module *const module, enum usart_callback callback_type) Enables the callback function registered by the usart_register_callback. The callback function will be called from the interrupt handler when the conditions for the callback type are met. Table 16-18. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] callback_type Callback type given by an enum Function usart_disable_callback() Disable callback. void usart_disable_callback( struct usart_module *const module, enum usart_callback callback_type) Disables the callback function registered by the usart_register_callback, and the callback will not be called from the interrupt routine. Table 16-19. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] callback_type Callback type given by an enum 16.6.4.5 Writing and Reading Function usart_write_job() Asynchronous write a single char. enum status_code usart_write_job( struct usart_module *const module, const uint16_t * tx_data) Sets up the driver to write the data given. If registered and enabled, a callback function will be called when the transmit is completed. Table 16-20. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 365 Data direction Parameter name Description [in] tx_data Data to transfer Returns Status of the operation. Table 16-21. Return Values Return value Description STATUS_OK If operation was completed STATUS_BUSY If operation was not completed, due to the USART module being busy STATUS_ERR_DENIED If the transmitter is not enabled Function usart_read_job() Asynchronous read a single char. enum status_code usart_read_job( struct usart_module *const module, uint16_t *const rx_data) Sets up the driver to read data from the USART module to the data pointer given. If registered and enabled, a callback will be called when the receiving is completed. Table 16-22. Parameters Returns Data direction Parameter name Description [in] module Pointer to USART software instance struct [out] rx_data Pointer to where received data should be put Status of the operation. Table 16-23. Return Values Return value Description STATUS_OK If operation was completed STATUS_BUSY If operation was not completed Function usart_write_buffer_job() Asynchronous buffer write. enum status_code usart_write_buffer_job( struct usart_module *const module, uint8_t * tx_data, uint16_t length) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 366 Sets up the driver to write a given buffer over the USART. If registered and enabled, a callback function will be called. Table 16-24. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] tx_data Pointer do data buffer to transmit [in] length Length of the data to transmit Note if using 9-bit data, the array that *tx_data point to should be defined as uint16_t array and should be casted to uint8_t* pointer. Because it is an address pointer, the highest byte is not discarded. For example: #define TX_LEN 3 uint16_t tx_buf[TX_LEN] = {0x0111, 0x0022, 0x0133}; usart_write_buffer_job(&module, (uint8_t*)tx_buf, TX_LEN); Returns Status of the operation. Table 16-25. Return Values Return value Description STATUS_OK If operation was completed successfully. STATUS_BUSY If operation was not completed, due to the USART module being busy STATUS_ERR_INVALID_ARG If operation was not completed, due to invalid arguments STATUS_ERR_DENIED If the transmitter is not enabled Function usart_read_buffer_job() Asynchronous buffer read. enum status_code usart_read_buffer_job( struct usart_module *const module, uint8_t * rx_data, uint16_t length) Sets up the driver to read from the USART to a given buffer. If registered and enabled, a callback function will be called. Table 16-26. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [out] rx_data Pointer to data buffer to receive [in] length Data buffer length AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 367 Note if using 9-bit data, the array that *rx_data point to should be defined as uint16_t array and should be casted to uint8_t* pointer. Because it is an address pointer, the highest byte is not discarded. For example: #define RX_LEN 3 uint16_t rx_buf[RX_LEN] = {0x0,}; usart_read_buffer_job(&module, (uint8_t*)rx_buf, RX_LEN); Returns Status of the operation. Table 16-27. Return Values Return value Description STATUS_OK If operation was completed STATUS_BUSY If operation was not completed, due to the USART module being busy STATUS_ERR_INVALID_ARG If operation was not completed, due to invalid arguments STATUS_ERR_DENIED If the transmitter is not enabled Function usart_abort_job() Cancels ongoing read/write operation. void usart_abort_job( struct usart_module *const module, enum usart_transceiver_type transceiver_type) Cancels the ongoing read/write operation modifying parameters in the USART software struct. Table 16-28. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct [in] transceiver_type Transfer type to cancel Function usart_get_job_status() Get status from the ongoing or last asynchronous transfer operation. enum status_code usart_get_job_status( struct usart_module *const module, enum usart_transceiver_type transceiver_type) Returns the error from a given ongoing or last asynchronous transfer operation. Either from a read or write transfer. Table 16-29. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 368 Data direction Parameter name Description [in] transceiver_type Transfer type to check Returns Status of the given job. Table 16-30. Return Values Return value Description STATUS_OK No error occurred during the last transfer STATUS_BUSY A transfer is ongoing STATUS_ERR_BAD_DATA The last operation was aborted due to a parity error. The transfer could be affected by external noise STATUS_ERR_BAD_FORMAT The last operation was aborted due to a frame error STATUS_ERR_OVERFLOW The last operation was aborted due to a buffer overflow STATUS_ERR_INVALID_ARG An invalid transceiver enum given 16.6.4.6 Function usart_disable() Disable module. void usart_disable( const struct usart_module *const module) Disables the USART module. Table 16-31. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct 16.6.4.7 Function usart_enable() Enable the module. void usart_enable( const struct usart_module *const module) Enables the USART module. Table 16-32. Parameters Data direction Parameter name Description [in] module Pointer to USART software instance struct 16.6.4.8 Function usart_get_config_defaults() Initializes the device to predefined defaults. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 369 void usart_get_config_defaults( struct usart_config *const config) Initialize the USART device to predefined defaults: ● 8-bit asynchronous USART ● No parity ● One stop bit ● 9600 baud ● Transmitter enabled ● Receiver enabled ● GCLK generator 0 as clock source ● Default pin configuration The configuration struct will be updated with the default configuration. Table 16-33. Parameters Data direction Parameter name Description [in, out] config Pointer to configuration struct 16.6.4.9 Function usart_init() Initializes the device. enum status_code usart_init( struct usart_module *const module, Sercom *const hw, const struct usart_config *const config) Initializes the USART device based on the setting specified in the configuration struct. Table 16-34. Parameters Returns Data direction Parameter name Description [out] module Pointer to USART device [in] hw Pointer to USART hardware instance [in] config Pointer to configuration struct Status of the initialization. Table 16-35. Return Values Return value Description STATUS_OK The initialization was successful STATUS_BUSY The USART module is busy resetting STATUS_ERR_DENIED The USART have not been disabled in advance of initialization AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 370 Return value Description STATUS_ERR_INVALID_ARG The configuration struct contains invalid configuration STATUS_ERR_ALREADY_INITIALIZED The SERCOM instance has already been initialized with different clock configuration STATUS_ERR_BAUD_UNAVAILABLE The BAUD rate given by the configuration struct cannot be reached with the current clock configuration 16.6.4.10 Function usart_is_syncing() Check if peripheral is busy syncing registers across clock domains. bool usart_is_syncing( const struct usart_module *const module) Return peripheral synchronization status. If doing a non-blocking implementation this function can be used to check the sync state and hold of any new actions until sync is complete. If this functions is not run; the functions will block until the sync has completed. Table 16-36. Parameters Data direction Parameter name Description [in] module Pointer to peripheral module Returns Peripheral sync status. Table 16-37. Return Values Return value Description true Peripheral is busy syncing false Peripheral is not busy syncing and can be read/written without stalling the bus. 16.6.4.11 Function usart_reset() Resets the USART module. void usart_reset( const struct usart_module *const module) Disables and resets the USART module. Table 16-38. Parameters 16.6.5 Data direction Parameter name Description [in] module Pointer to the USART software instance struct Enumeration Definitions 16.6.5.1 Enum usart_callback Callbacks for the Asynchronous USART driver. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 371 Table 16-39. Members Enum value Description USART_CALLBACK_BUFFER_TRANSMITTED Callback for buffer transmitted. USART_CALLBACK_BUFFER_RECEIVED Callback for buffer received. USART_CALLBACK_ERROR Callback for error. 16.6.5.2 Enum usart_character_size Number of bits for the character sent in a frame. Table 16-40. Members Enum value Description USART_CHARACTER_SIZE_5BIT The char being sent in a frame is five bits long. USART_CHARACTER_SIZE_6BIT The char being sent in a frame is six bits long. USART_CHARACTER_SIZE_7BIT The char being sent in a frame is seven bits long. USART_CHARACTER_SIZE_8BIT The char being sent in a frame is eight bits long. USART_CHARACTER_SIZE_9BIT The char being sent in a frame is nine bits long. 16.6.5.3 Enum usart_dataorder The data order decides which of MSB or LSB is shifted out first when data is transferred. Table 16-41. Members Enum value Description USART_DATAORDER_MSB The MSB will be shifted out first during transmission, and shifted in first during reception. USART_DATAORDER_LSB The LSB will be shifted out first during transmission, and shifted in first during reception. 16.6.5.4 Enum usart_parity Select parity USART parity mode. Table 16-42. Members Enum value Description USART_PARITY_ODD For odd parity checking, the parity bit will be set if number of ones being transferred is even. USART_PARITY_EVEN For even parity checking, the parity bit will be set if number of ones being received is odd. USART_PARITY_NONE No parity checking will be executed, and there will be no parity bit in the received frame. 16.6.5.5 Enum usart_signal_mux_settings Set the functionality of the SERCOM pins. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 372 See SERCOM USART MUX Settings for a description of the various MUX setting options. Table 16-43. Members Enum value Description USART_RX_0_TX_0_XCK_1 MUX setting RX_0_TX_0_XCK_1. USART_RX_0_TX_2_XCK_3 MUX setting RX_0_TX_2_XCK_3. USART_RX_1_TX_0_XCK_1 MUX setting RX_1_TX_0_XCK_1. USART_RX_1_TX_2_XCK_3 MUX setting RX_1_TX_2_XCK_3. USART_RX_2_TX_0_XCK_1 MUX setting RX_2_TX_0_XCK_1. USART_RX_2_TX_2_XCK_3 MUX setting RX_2_TX_2_XCK_3. USART_RX_3_TX_0_XCK_1 MUX setting RX_3_TX_0_XCK_1. USART_RX_3_TX_2_XCK_3 MUX setting RX_3_TX_2_XCK_3. 16.6.5.6 Enum usart_stopbits Number of stop bits for a frame. Table 16-44. Members Enum value Description USART_STOPBITS_1 Each transferred frame contains one stop bit. USART_STOPBITS_2 Each transferred frame contains two stop bits. 16.6.5.7 Enum usart_transceiver_type Select Receiver or Transmitter. Table 16-45. Members Enum value Description USART_TRANSCEIVER_RX The parameter is for the Receiver. USART_TRANSCEIVER_TX The parameter is for the Transmitter. 16.6.5.8 Enum usart_transfer_mode Select USART transfer mode. Table 16-46. Members 16.7 Enum value Description USART_TRANSFER_SYNCHRONOUSLY Transfer of data is done synchronously. USART_TRANSFER_ASYNCHRONOUSLY Transfer of data is done asynchronously. SERCOM USART MUX Settings The following lists the possible internal SERCOM module pad function assignments, for the four SERCOM pads when in USART mode. Note that this is in addition to the physical GPIO pin MUX of the device, and can be used in conjunction to optimize the serial data pin-out. When TX and RX are connected to the same pin, the USART will operate in half-duplex mode if both the transmitter and receivers are enabled. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 373 Note When RX and XCK are connected to the same pin, the receiver must not be enabled if the USART is configured to use an external clock. MUX/Pad PAD 0 PAD 1 PAD 2 PAD 3 RX_0_TX_0_XCK_1 TX / RX XCK - - RX_0_TX_2_XCK_3 RX - TX XCK RX_1_TX_0_XCK_1 TX RX / XCK - - RX_1_TX_2_XCK_3 - RX TX XCK RX_2_TX_0_XCK_1 TX XCK RX - RX_2_TX_2_XCK_3 - - TX / RX XCK RX_3_TX_0_XCK_1 TX XCK - RX RX_3_TX_2_XCK_3 - - TX RX / XCK 16.8 Extra Information for SERCOM USART Driver 16.8.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 16.8.2 Acronym Description SERCOM Serial Communication Interface USART Universal Synchronous and Asynchronous Serial Receiver and Transmitter LSB Least Significant Bit MSB Most Significant Bit DMA Direct Memory Access Dependencies This driver has the following dependencies: 16.8.3 ● System Pin Multiplexer Driver ● System clock configuration Errata There are no errata related to this driver. 16.8.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add support for SAML21 (same features as SAMD21) Add support for SAMD10/D11 (same features as SAMD21) Add support for SAMR21 (same features as SAMD21) Add support for SAMD21 and added new feature as below: ● Oversample AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 374 Changelog ● Buffer overflow notification ● Irda ● Lin slave ● Start frame detection ● Hardware flow control ● Collision detection ● DMA support ● Added new transmitter_enable and receiver_enable Boolean values to struct usart_config ● Altered usart_write_* and usart_read_* functions to abort with an error code if the relevant transceiver is not enabled ● Fixed usart_write_buffer_wait() and usart_read_buffer_wait() not aborting correctly when a timeout condition occurs Initial Release 16.9 Examples for SERCOM USART Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Serial USART Driver (SERCOM USART). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 16.9.1 ● Quick Start Guide for SERCOM USART - Basic ● Quick Start Guide for SERCOM USART - Callback ● Quick Start Guide for Using DMA with SERCOM USART Quick Start Guide for SERCOM USART - Basic This quick start will echo back characters typed into the terminal. In this use case the USART will be configured with the following settings: ● Asynchronous mode ● 9600 Baudrate ● 8-bits, No Parity and one Stop Bit ● TX and RX enabled and connected to the Xplained Pro Embedded Debugger virtual COM port 16.9.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Add to the main application source file, outside of any functions: struct usart_module usart_instance; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 375 Copy-paste the following setup code to your user application: void configure_usart(void) { struct usart_config config_usart; usart_get_config_defaults(&config_usart); config_usart.baudrate config_usart.mux_setting config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 config_usart.pinmux_pad3 = = = = = = 9600; EDBG_CDC_SERCOM_MUX_SETTING; EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; EDBG_CDC_SERCOM_PINMUX_PAD3; while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } usart_enable(&usart_instance); } Add to user application initialization (typically the start of main()): configure_usart(); Workflow 1. Create a module software instance structure for the USART module to store the USART driver state while it is in use. struct usart_module usart_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the USART module. a. Create a USART module configuration struct, which can be filled out to adjust the configuration of a physical USART peripheral. struct usart_config config_usart; b. Initialize the USART configuration struct with the module's default values. usart_get_config_defaults(&config_usart); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the USART settings to configure the physical pinout, baudrate, and other relevant parameters. config_usart.baudrate = 9600; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 376 config_usart.mux_setting config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 config_usart.pinmux_pad3 d. = = = = = EDBG_CDC_SERCOM_MUX_SETTING; EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; EDBG_CDC_SERCOM_PINMUX_PAD3; Configure the USART module with the desired settings, retrying while the driver is busy until the configuration is stressfully set. while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } e. Enable the USART module. usart_enable(&usart_instance); 16.9.1.2 Use Case Code Copy-paste the following code to your user application: uint8_t string[] = "Hello World!\r\n"; usart_write_buffer_wait(&usart_instance, string, sizeof(string)); uint16_t temp; while (true) { if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) { while (usart_write_wait(&usart_instance, temp) != STATUS_OK) { } } } Workflow 1. Send a string to the USART to show the demo is running, blocking until all characters have been sent. uint8_t string[] = "Hello World!\r\n"; usart_write_buffer_wait(&usart_instance, string, sizeof(string)); 2. Enter an infinite loop to continuously echo received values on the USART. while (true) { if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) { while (usart_write_wait(&usart_instance, temp) != STATUS_OK) { } } } 3. Perform a blocking read of the USART, storing the received character into the previously declared temporary variable. if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 377 4. Echo the received variable back to the USART via a blocking write. while (usart_write_wait(&usart_instance, temp) != STATUS_OK) { } 16.9.2 Quick Start Guide for SERCOM USART - Callback This quick start will echo back characters typed into the terminal, using asynchronous TX and RX callbacks from the USART peripheral. In this use case the USART will be configured with the following settings: ● Asynchronous mode ● 9600 Baudrate ● 8-bits, No Parity and one Stop Bit ● TX and RX enabled and connected to the Xplained Pro Embedded Debugger virtual COM port 16.9.2.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Add to the main application source file, outside of any functions: struct usart_module usart_instance; #define MAX_RX_BUFFER_LENGTH 5 volatile uint8_t rx_buffer[MAX_RX_BUFFER_LENGTH]; Copy-paste the following callback function code to your user application: void usart_read_callback(const struct usart_module *const usart_module) { usart_write_buffer_job(&usart_instance, (uint8_t *)rx_buffer, MAX_RX_BUFFER_LENGTH); } void usart_write_callback(const struct usart_module *const usart_module) { port_pin_toggle_output_level(LED_0_PIN); } Copy-paste the following setup code to your user application: void configure_usart(void) { struct usart_config config_usart; usart_get_config_defaults(&config_usart); config_usart.baudrate config_usart.mux_setting config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 = = = = = 9600; EDBG_CDC_SERCOM_MUX_SETTING; EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 378 config_usart.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3; while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } usart_enable(&usart_instance); } void configure_usart_callbacks(void) { usart_register_callback(&usart_instance, usart_write_callback, USART_CALLBACK_BUFFER_TRANSMITTED); usart_register_callback(&usart_instance, usart_read_callback, USART_CALLBACK_BUFFER_RECEIVED); usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_TRANSMITTED); usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_RECEIVED); } Add to user application initialization (typically the start of main()): configure_usart(); configure_usart_callbacks(); Workflow 1. Create a module software instance structure for the USART module to store the USART driver state while it is in use. struct usart_module usart_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the USART module. a. Create a USART module configuration struct, which can be filled out to adjust the configuration of a physical USART peripheral. struct usart_config config_usart; b. Initialize the USART configuration struct with the module's default values. usart_get_config_defaults(&config_usart); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the USART settings to configure the physical pinout, baudrate, and other relevant parameters. config_usart.baudrate = 9600; config_usart.mux_setting = EDBG_CDC_SERCOM_MUX_SETTING; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 379 config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 config_usart.pinmux_pad3 d. = = = = EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; EDBG_CDC_SERCOM_PINMUX_PAD3; Configure the USART module with the desired settings, retrying while the driver is busy until the configuration is stressfully set. while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } e. Enable the USART module. usart_enable(&usart_instance); 3. Configure the USART callbacks. a. Register the TX and RX callback functions with the driver. usart_register_callback(&usart_instance, usart_write_callback, USART_CALLBACK_BUFFER_TRANSMITTED); usart_register_callback(&usart_instance, usart_read_callback, USART_CALLBACK_BUFFER_RECEIVED); b. Enable the TX and RX callbacks so that they will be called by the driver when appropriate. usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_TRANSMITTED); usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_RECEIVED); 16.9.2.2 Use Case Code Copy-paste the following code to your user application: system_interrupt_enable_global(); uint8_t string[] = "Hello World!\r\n"; usart_write_buffer_job(&usart_instance, string, sizeof(string)); while (true) { usart_read_buffer_job(&usart_instance, (uint8_t *)rx_buffer, MAX_RX_BUFFER_LENGTH); } Workflow 1. Enable global interrupts, so that the callbacks can be fired. system_interrupt_enable_global(); 2. Send a string to the USART to show the demo is running, blocking until all characters have been sent. uint8_t string[] = "Hello World!\r\n"; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 380 usart_write_buffer_job(&usart_instance, string, sizeof(string)); 3. Enter an infinite loop to continuously echo received values on the USART. while (true) { 4. Perform an asynchronous read of the USART, which will fire the registered callback when characters are received. usart_read_buffer_job(&usart_instance, (uint8_t *)rx_buffer, MAX_RX_BUFFER_LENGTH); 16.9.3 Quick Start Guide for Using DMA with SERCOM USART The supported board list: ● SAML21 Xplained Pro ● SAMD21 Xplained Pro ● SAMR21 Xplained Pro ● SAMD11 Xplained Pro This quick start will receiving eight bytes of data from PC terminal and transmit back the string to the terminal through DMA. In this use case the USART will be configured with the following settings: ● Asynchronous mode ● 9600 Baudrate ● 8-bits, No Parity and one Stop Bit ● TX and RX enabled and connected to the Xplained Pro Embedded Debugger virtual COM port 16.9.3.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Add to the main application source file, outside of any functions: struct usart_module usart_instance; struct dma_resource usart_dma_resource_rx; struct dma_resource usart_dma_resource_tx; #define BUFFER_LEN 8 static uint16_t string[BUFFER_LEN]; COMPILER_ALIGNED(16) DmacDescriptor example_descriptor_rx; DmacDescriptor example_descriptor_tx; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 381 Copy-paste the following setup code to your user application: static void transfer_done_rx( const struct dma_resource* const resource ) { dma_start_transfer_job(&usart_dma_resource_tx); } static void transfer_done_tx( const struct dma_resource* const resource ) { dma_start_transfer_job(&usart_dma_resource_rx); } static void configure_dma_resource_rx(struct dma_resource *resource) { struct dma_resource_config config; dma_get_config_defaults(&config); config.peripheral_trigger = EDBG_CDC_SERCOM_DMAC_ID_RX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } dma_allocate(resource, &config); static void setup_transfer_descriptor_rx(DmacDescriptor *descriptor) { struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.src_increment_enable = false; descriptor_config.block_transfer_count = BUFFER_LEN; descriptor_config.destination_address = (uint32_t)string + sizeof(string); descriptor_config.source_address = (uint32_t)(&usart_instance.hw->USART.DATA.reg); } dma_descriptor_create(descriptor, &descriptor_config); static void configure_dma_resource_tx(struct dma_resource *resource) { struct dma_resource_config config; dma_get_config_defaults(&config); config.peripheral_trigger = EDBG_CDC_SERCOM_DMAC_ID_TX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; } dma_allocate(resource, &config); static void setup_transfer_descriptor_tx(DmacDescriptor *descriptor) { struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.dst_increment_enable = false; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 382 descriptor_config.block_transfer_count = BUFFER_LEN; descriptor_config.source_address = (uint32_t)string + sizeof(string); descriptor_config.destination_address = (uint32_t)(&usart_instance.hw->USART.DATA.reg); } dma_descriptor_create(descriptor, &descriptor_config); static void configure_usart(void) { struct usart_config config_usart; usart_get_config_defaults(&config_usart); config_usart.baudrate config_usart.mux_setting config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 config_usart.pinmux_pad3 = = = = = = 9600; EDBG_CDC_SERCOM_MUX_SETTING; EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; EDBG_CDC_SERCOM_PINMUX_PAD3; while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } } usart_enable(&usart_instance); Add to user application initialization (typically the start of main()): configure_usart(); configure_dma_resource_rx(&usart_dma_resource_rx); configure_dma_resource_tx(&usart_dma_resource_tx); setup_transfer_descriptor_rx(&example_descriptor_rx); setup_transfer_descriptor_tx(&example_descriptor_tx); dma_add_descriptor(&usart_dma_resource_rx, &example_descriptor_rx); dma_add_descriptor(&usart_dma_resource_tx, &example_descriptor_tx); dma_register_callback(&usart_dma_resource_rx, transfer_done_rx, DMA_CALLBACK_TRANSFER_DONE); dma_register_callback(&usart_dma_resource_tx, transfer_done_tx, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&usart_dma_resource_rx, DMA_CALLBACK_TRANSFER_DONE); dma_enable_callback(&usart_dma_resource_tx, DMA_CALLBACK_TRANSFER_DONE); Workflow Create variables 1. Create a module software instance structure for the USART module to store the USART driver state while it is in use. struct usart_module usart_instance; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 383 Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Create module software instance structures for DMA resources to store the DMA resource state while it is in use. struct dma_resource usart_dma_resource_rx; struct dma_resource usart_dma_resource_tx; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 3. Create a buffer to store the data to be transferred /received. #define BUFFER_LEN 8 static uint16_t string[BUFFER_LEN]; 4. Create DMA transfer descriptors for RX/TX. COMPILER_ALIGNED(16) DmacDescriptor example_descriptor_rx; DmacDescriptor example_descriptor_tx; Configure the USART 1. Create a USART module configuration struct, which can be filled out to adjust the configuration of a physical USART peripheral. struct usart_config config_usart; 2. Initialize the USART configuration struct with the module's default values. usart_get_config_defaults(&config_usart); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Alter the USART settings to configure the physical pinout, baudrate, and other relevant parameters. config_usart.baudrate config_usart.mux_setting config_usart.pinmux_pad0 config_usart.pinmux_pad1 config_usart.pinmux_pad2 config_usart.pinmux_pad3 4. = = = = = = 9600; EDBG_CDC_SERCOM_MUX_SETTING; EDBG_CDC_SERCOM_PINMUX_PAD0; EDBG_CDC_SERCOM_PINMUX_PAD1; EDBG_CDC_SERCOM_PINMUX_PAD2; EDBG_CDC_SERCOM_PINMUX_PAD3; Configure the USART module with the desired settings, retrying while the driver is busy until the configuration is stressfully set. while (usart_init(&usart_instance, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 384 EDBG_CDC_MODULE, &config_usart) != STATUS_OK) { } 5. Enable the USART module. usart_enable(&usart_instance); Configure DMA 1. Create a callback function of receiver done. static void transfer_done_rx( const struct dma_resource* const resource ) { dma_start_transfer_job(&usart_dma_resource_tx); } 2. Create a callback function of transmission done. static void transfer_done_tx( const struct dma_resource* const resource ) { dma_start_transfer_job(&usart_dma_resource_rx); } 3. Create a DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config config; 4. Initialize the DMA resource configuration struct with the module's default values. dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 5. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM TX empty trigger causes a beat transfer in this example. config.peripheral_trigger = EDBG_CDC_SERCOM_DMAC_ID_RX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; 6. Allocate a DMA resource with the configurations. dma_allocate(resource, &config); 7. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; 8. Initialize the DMA transfer descriptor configuration struct with the module's default values. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 385 dma_descriptor_get_config_defaults(&descriptor_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 9. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.src_increment_enable = false; descriptor_config.block_transfer_count = BUFFER_LEN; descriptor_config.destination_address = (uint32_t)string + sizeof(string); descriptor_config.source_address = (uint32_t)(&usart_instance.hw->USART.DATA.reg); 10. Create the DMA transfer descriptor. dma_descriptor_create(descriptor, &descriptor_config); 11. Create a DMA resource configuration structure for TX, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_resource_config config; 12. Initialize the DMA resource configuration struct with the module's default values. dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 13. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM RX Ready trigger causes a beat transfer in this example. config.peripheral_trigger = EDBG_CDC_SERCOM_DMAC_ID_TX; config.trigger_action = DMA_TRIGGER_ACTON_BEAT; 14. Allocate a DMA resource with the configurations. dma_allocate(resource, &config); 15. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; 16. Initialize the DMA transfer descriptor configuration struct with the module's default values. dma_descriptor_get_config_defaults(&descriptor_config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 386 Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 17. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.dst_increment_enable = false; descriptor_config.block_transfer_count = BUFFER_LEN; descriptor_config.source_address = (uint32_t)string + sizeof(string); descriptor_config.destination_address = (uint32_t)(&usart_instance.hw->USART.DATA.reg); 18. Create the DMA transfer descriptor. dma_descriptor_create(descriptor, &descriptor_config); 16.9.3.2 Use Case Code Copy-paste the following code to your user application: dma_start_transfer_job(&usart_dma_resource_rx); while (true) { } Workflow 1. Wait for receiving data. dma_start_transfer_job(&usart_dma_resource_rx); 2. Enter endless loop. while (true) { } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 387 17. SAM System Clock Management Driver (SYSTEM CLOCK) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's clocking related functions. This includes the various clock sources, bus clocks, and generic clocks within the device, with functions to manage the enabling, disabling, source selection, and prescaling of clocks to various internal peripherals. The following peripherals are used by this module: ● GCLK (Generic Clock Management) ● PM (Power Management) ● SYSCTRL (Clock Source Control) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 The outline of this documentation is as follows: 17.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 17.2 Module Overview The SAM devices contain a sophisticated clocking system, which is designed to give the maximum flexibility to the user application. This system allows a system designer to tune the performance and power consumption of the device in a dynamic manner, to achieve the best trade-off between the two for a particular application. This driver provides a set of functions for the configuration and management of the various clock related functionality within the device. 17.2.1 Driver Feature Macro Definition 1 Driver Feature Macro Supported devices FEATURE_SYSTEM_CLOCK_DPLL SAMD21, SAMR21, SAMD10, SAMD11 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 388 Note 17.2.2 The specific features are only available in the driver when the selected device supports those features. Clock Sources The SAM devices have a number of master clock source modules, each of which being capable of producing a stabilized output frequency, which can then be fed into the various peripherals and modules within the device. Possible clock source modules include internal R/C oscillators, internal DFLL modules, as well as external crystal oscillators and/or clock inputs. 17.2.3 CPU / Bus Clocks The CPU and AHB/APBx buses are clocked by the same physical clock source (referred in this module as the Main Clock), however the APBx buses may have additional prescaler division ratios set to give each peripheral bus a different clock speed. The general main clock tree for the CPU and associated buses is shown in Figure 17-1: CPU / Bus Clocks on page 389. Figure 17-1. CPU / Bus Clocks CP U Bu s AH B Bu s Clo c k S o u r c e s 17.2.4 M a in Bu s P r e s c a le r AP BA Bu s P r e s c a le r AP BA Bu s AP BB Bu s P r e s c a le r AP BB Bu s AP BC Bu s P r e s c a le r AP BC Bu s Clock Masking To save power, the input clock to one or more peripherals on the AHB and APBx buses can be masked away when masked, no clock is passed into the module. Disabling of clocks of unused modules will prevent all access to the masked module, but will reduce the overall device power consumption. 17.2.5 Generic Clocks Within the SAM devices there are a number of Generic Clocks; these are used to provide clocks to the various peripheral clock domains in the device in a standardized manner. One or more master source clocks can be AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 389 selected as the input clock to a Generic Clock Generator, which can prescale down the input frequency to a slower rate for use in a peripheral. Additionally, a number of individually selectable Generic Clock Channels are provided, which multiplex and gate the various generator outputs for one or more peripherals within the device. This setup allows for a single common generator to feed one or more channels, which can then be enabled or disabled individually as required. Figure 17-2. Generic Clocks Clo c k Sou r ce a Ch a n n e l x P e r ip h e r a l x Ch a n n e l y P e r ip h e r a l y Ge n e r a t o r 1 17.2.5.1 Clock Chain Example An example setup of a complete clock chain within the device is shown in Figure 17-3: Clock Chain Example on page 390. Figure 17-3. Clock Chain Example 8 M H z R/C Os c illa t o r (OS C8 M ) E xt e r n a l Os c illa t o r Ch a n n e l y S E RCOM M o d u le Ch a n n e l z Tim e r M o d u le Ch a n n e l x Co r e CP U Ge n e r a t o r 1 Ge n e r a t o r 0 17.2.5.2 Generic Clock Generators Each Generic Clock generator within the device can source its input clock from one of the provided Source Clocks, and prescale the output for one or more Generic Clock Channels in a one-to-many relationship. The generators thus allow for several clocks to be generated of different frequencies, power usages, and accuracies, which can be turned on and off individually to disable the clocks to multiple peripherals as a group. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 390 17.2.5.3 Generic Clock Channels To connect a Generic Clock Generator to a peripheral within the device, a Generic Clock Channel is used. Each peripheral or peripheral group has an associated Generic Clock Channel, which serves as the clock input for the peripheral(s). To supply a clock to the peripheral module(s), the associated channel must be connected to a running Generic Clock Generator and the channel enabled. 17.3 Special Considerations There are no special considerations for this module. 17.4 Extra Information For extra information, see Extra Information for SYSTEM CLOCK Driver. This includes: 17.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for System Clock Driver. 17.6 API Overview 17.6.1 Structure Definitions 17.6.1.1 Struct system_clock_source_dfll_config DFLL oscillator configuration structure. Table 17-1. Members Type Name Description enum system_clock_dfll_chill_cycle chill_cycle Enable Chill Cycle. uint8_t coarse_max_step Coarse adjustment maximum step size (Closed loop mode). uint8_t coarse_value Coarse calibration value (Open loop mode). uint16_t fine_max_step Fine adjustment maximum step size (Closed loop mode). uint16_t fine_value Fine calibration value (Open loop mode). enum system_clock_dfll_loop_mode loop_mode Loop mode. uint16_t multiply_factor DFLL multiply factor (Closed loop mode. bool on_demand Run On Demand. If this is set the DFLL won't run until requested by a peripheral. enum system_clock_dfll_quick_lock quick_lock Enable Quick Lock. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 391 Type Name Description enum system_clock_dfll_stable_tracking stable_tracking DFLL tracking after fine lock. enum system_clock_dfll_wakeup_lock wakeup_lock DFLL lock state on wakeup. 17.6.1.2 Struct system_clock_source_osc32k_config Internal 32KHz (nominal) oscillator configuration structure. Table 17-2. Members Type Name Description bool enable_1khz_output Enable 1KHz output. bool enable_32khz_output Enable 32KHz output. bool on_demand Run On Demand. If this is set the OSC32K won't run until requested by a peripheral. bool run_in_standby Keep the OSC32K enabled in standby sleep mode. enum system_osc32k_startup startup_time Startup time. bool write_once Lock configuration after it has been written, a device reset will release the lock. 17.6.1.3 Struct system_clock_source_osc8m_config Internal 8MHz (nominal) oscillator configuration structure. Table 17-3. Members Type Name Description bool on_demand Run On Demand. If this is set the OSC8M won't run until requested by a peripheral. enum system_osc8m_div prescaler bool run_in_standby Keep the OSC8M enabled in standby sleep mode. 17.6.1.4 Struct system_clock_source_xosc32k_config External 32KHz oscillator clock configuration structure. Table 17-4. Members Type Name Description bool auto_gain_control Enable automatic amplitude control. bool enable_1khz_output Enable 1KHz output. bool enable_32khz_output Enable 32KHz output. enum system_clock_external external_clock External clock type. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 392 Type Name Description uint32_t frequency External clock/crystal frequency. bool on_demand Run On Demand. If this is set the XOSC32K won't run until requested by a peripheral. bool run_in_standby Keep the XOSC32K enabled in standby sleep mode. enum system_xosc32k_startup startup_time Crystal oscillator start-up time. bool write_once Lock configuration after it has been written, a device reset will release the lock. 17.6.1.5 Struct system_clock_source_xosc_config External oscillator clock configuration structure. Table 17-5. Members Type Name Description bool auto_gain_control Enable automatic amplitude gain control. enum system_clock_external external_clock External clock type. uint32_t frequency External clock/crystal frequency. bool on_demand Run On Demand. If this is set the XOSC won't run until requested by a peripheral. bool run_in_standby Keep the XOSC enabled in standby sleep mode. enum system_xosc_startup startup_time Crystal oscillator start-up time. 17.6.1.6 Struct system_gclk_chan_config Configuration structure for a Generic Clock channel. This structure should be initialized by the system_gclk_chan_get_config_defaults() function before being modified by the user application. Table 17-6. Members Type Name Description enum gclk_generator source_generator Generic Clock Generator source channel. 17.6.1.7 Struct system_gclk_gen_config Configuration structure for a Generic Clock Generator channel. This structure should be initialized by the system_gclk_gen_get_config_defaults() function before being modified by the user application. Table 17-7. Members Type Name Description uint32_t division_factor Integer division factor of the clock output compared to the input. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 393 17.6.2 Type Name Description bool high_when_disabled If true, the generator output level is high when disabled. bool output_enable If true, enables GCLK generator clock output to a GPIO pin. bool run_in_standby If true, the clock is kept enabled during device standby mode. uint8_t source_clock Source clock input channel index, see the system_clock_source. Function Definitions 17.6.2.1 External Oscillator Management Function system_clock_source_xosc_get_config_defaults() Retrieve the default configuration for XOSC. void system_clock_source_xosc_get_config_defaults( struct system_clock_source_xosc_config *const config) Fills a configuration structure with the default configuration for an external oscillator module: ● External Crystal ● Start-up time of 16384 external clock cycles ● Automatic crystal gain control mode enabled ● Frequency of 12MHz ● Don't run in STANDBY sleep mode ● Run only when requested by peripheral (on demand) Table 17-8. Parameters Data direction Parameter name Description [out] config Configuration structure to fill with default values Function system_clock_source_xosc_set_config() Configure the external oscillator clock source. void system_clock_source_xosc_set_config( struct system_clock_source_xosc_config *const config) Configures the external oscillator clock source with the given configuration settings. Table 17-9. Parameters Data direction Parameter name Description [in] config External oscillator configuration structure containing the new config AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 394 17.6.2.2 External 32KHz Oscillator Management Function system_clock_source_xosc32k_get_config_defaults() Retrieve the default configuration for XOSC32K. void system_clock_source_xosc32k_get_config_defaults( struct system_clock_source_xosc32k_config *const config) Fills a configuration structure with the default configuration for an external 32KHz oscillator module: ● External Crystal ● Start-up time of 16384 external clock cycles ● Automatic crystal gain control mode disabled ● Frequency of 32.768KHz ● 1KHz clock output disabled ● 32KHz clock output enabled ● Don't run in STANDBY sleep mode ● Run only when requested by peripheral (on demand) ● Don't lock registers after configuration has been written Table 17-10. Parameters Data direction Parameter name Description [out] config Configuration structure to fill with default values Function system_clock_source_xosc32k_set_config() Configure the XOSC32K external 32KHz oscillator clock source. void system_clock_source_xosc32k_set_config( struct system_clock_source_xosc32k_config *const config) Configures the external 32KHz oscillator clock source with the given configuration settings. Table 17-11. Parameters Data direction Parameter name Description [in] config XOSC32K configuration structure containing the new config 17.6.2.3 Internal 32KHz Oscillator Management Function system_clock_source_osc32k_get_config_defaults() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 395 Retrieve the default configuration for OSC32K. void system_clock_source_osc32k_get_config_defaults( struct system_clock_source_osc32k_config *const config) Fills a configuration structure with the default configuration for an internal 32KHz oscillator module: ● 1KHz clock output enabled ● 32KHz clock output enabled ● Don't run in STANDBY sleep mode ● Run only when requested by peripheral (on demand) ● Set startup time to 130 cycles ● Don't lock registers after configuration has been written Table 17-12. Parameters Data direction Parameter name Description [out] config Configuration structure to fill with default values Function system_clock_source_osc32k_set_config() Configure the internal OSC32K oscillator clock source. void system_clock_source_osc32k_set_config( struct system_clock_source_osc32k_config *const config) Configures the 32KHz (nominal) internal RC oscillator with the given configuration settings. Table 17-13. Parameters Data direction Parameter name Description [in] config OSC32K configuration structure containing the new config 17.6.2.4 Internal 8MHz Oscillator Management Function system_clock_source_osc8m_get_config_defaults() Retrieve the default configuration for OSC8M. void system_clock_source_osc8m_get_config_defaults( struct system_clock_source_osc8m_config *const config) Fills a configuration structure with the default configuration for an internal 8MHz (nominal) oscillator module: ● Clock output frequency divided by a factor of eight ● Don't run in STANDBY sleep mode ● Run only when requested by peripheral (on demand) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 396 Table 17-14. Parameters Data direction Parameter name Description [out] config Configuration structure to fill with default values Function system_clock_source_osc8m_set_config() Configure the internal OSC8M oscillator clock source. void system_clock_source_osc8m_set_config( struct system_clock_source_osc8m_config *const config) Configures the 8MHz (nominal) internal RC oscillator with the given configuration settings. Table 17-15. Parameters Data direction Parameter name Description [in] config OSC8M configuration structure containing the new config 17.6.2.5 Internal DFLL Management Function system_clock_source_dfll_get_config_defaults() Retrieve the default configuration for DFLL. void system_clock_source_dfll_get_config_defaults( struct system_clock_source_dfll_config *const config) Fills a configuration structure with the default configuration for a DFLL oscillator module: ● Open loop mode ● QuickLock mode enabled ● Chill cycle enabled ● Output frequency lock maintained during device wake-up ● Continuous tracking of the output frequency ● Default tracking values at the mid-points for both coarse and fine tracking parameters ● Don't run in STANDBY sleep mode ● Run only when requested by peripheral (on demand) Table 17-16. Parameters Data direction Parameter name Description [out] config Configuration structure to fill with default values Function system_clock_source_dfll_set_config() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 397 Configure the DFLL clock source. void system_clock_source_dfll_set_config( struct system_clock_source_dfll_config *const config) Configures the Digital Frequency Locked Loop clock source with the given configuration settings. Note The DFLL will be running when this function returns, as the DFLL module needs to be enabled in order to perform the module configuration. Table 17-17. Parameters Data direction Parameter name Description [in] config DFLL configuration structure containing the new config 17.6.2.6 Clock Source Management Function system_clock_source_write_calibration() enum status_code system_clock_source_write_calibration( const enum system_clock_source system_clock_source, const uint16_t calibration_value, const uint8_t freq_range) Function system_clock_source_enable() enum status_code system_clock_source_enable( const enum system_clock_source system_clock_source) Function system_clock_source_disable() Disables a clock source. enum status_code system_clock_source_disable( const enum system_clock_source clk_source) Disables a clock source that was previously enabled. Table 17-18. Parameters Data direction Parameter name Description [in] clock_source Clock source to disable Table 17-19. Return Values Return value Description STATUS_OK Clock source was disabled successfully STATUS_ERR_INVALID_ARG An invalid or unavailable clock source was given AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 398 Function system_clock_source_is_ready() Checks if a clock source is ready. bool system_clock_source_is_ready( const enum system_clock_source clk_source) Checks if a given clock source is ready to be used. Table 17-20. Parameters Data direction Parameter name Description [in] clock_source Clock source to check if ready Returns Ready state of the given clock source. Table 17-21. Return Values Return value Description true Clock source is enabled and ready false Clock source is disabled or not yet ready Function system_clock_source_get_hz() Retrieve the frequency of a clock source. uint32_t system_clock_source_get_hz( const enum system_clock_source clk_source) Determines the current operating frequency of a given clock source. Table 17-22. Parameters Returns Data direction Parameter name Description [in] clock_source Clock source to get the frequency Frequency of the given clock source, in Hz. 17.6.2.7 Main Clock Management Function system_cpu_clock_set_divider() Set main CPU clock divider. void system_cpu_clock_set_divider( const enum system_main_clock_div divider) Sets the clock divider used on the main clock to provide the CPU clock. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 399 Table 17-23. Parameters Data direction Parameter name Description [in] divider CPU clock divider to set Function system_cpu_clock_get_hz() Retrieves the current frequency of the CPU core. uint32_t system_cpu_clock_get_hz(void) Retrieves the operating frequency of the CPU core, obtained from the main generic clock and the set CPU bus divider. Returns Current CPU frequency in Hz. Function system_apb_clock_set_divider() Set APBx clock divider. enum status_code system_apb_clock_set_divider( const enum system_clock_apb_bus bus, const enum system_main_clock_div divider) Set the clock divider used on the main clock to provide the clock for the given APBx bus. Table 17-24. Parameters Returns Data direction Parameter name Description [in] divider APBx bus divider to set [in] bus APBx bus to set divider Status of the clock division change operation. Table 17-25. Return Values Return value Description STATUS_ERR_INVALID_ARG Invalid bus ID was given STATUS_OK The APBx clock was set successfully Function system_apb_clock_get_hz() Retrieves the current frequency of a ABPx. uint32_t system_apb_clock_get_hz( const enum system_clock_apb_bus bus) Retrieves the operating frequency of an APBx bus, obtained from the main generic clock and the set APBx bus divider. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 400 Returns Current APBx bus frequency in Hz. 17.6.2.8 Bus Clock Masking Function system_ahb_clock_set_mask() Set bits in the clock mask for the AHB bus. void system_ahb_clock_set_mask( const uint32_t ahb_mask) This function will set bits in the clock mask for the AHB bus. Any bits set to 1 will enable that clock, 0 bits in the mask will be ignored. Table 17-26. Parameters Data direction Parameter name Description [in] ahb_mask AHB clock mask to enable Function system_ahb_clock_clear_mask() Clear bits in the clock mask for the AHB bus. void system_ahb_clock_clear_mask( const uint32_t ahb_mask) This function will clear bits in the clock mask for the AHB bus. Any bits set to 1 will disable that clock, 0 bits in the mask will be ignored. Table 17-27. Parameters Data direction Parameter name Description [in] ahb_mask AHB clock mask to disable Function system_apb_clock_set_mask() Set bits in the clock mask for an APBx bus. enum status_code system_apb_clock_set_mask( const enum system_clock_apb_bus bus, const uint32_t mask) This function will set bits in the clock mask for an APBx bus. Any bits set to 1 will enable the corresponding module clock, zero bits in the mask will be ignored. Table 17-28. Parameters Data direction Parameter name Description [in] mask APBx clock mask, a SYSTEM_CLOCK_APB_APBx constant from the device header files AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 401 Data direction Parameter name Description [in] bus Bus to set clock mask bits for, a mask of PM_APBxMASK_* constants from the device header files Returns Status indicating the result of the clock mask change operation. Table 17-29. Return Values Return value Description STATUS_ERR_INVALID_ARG Invalid bus given STATUS_OK The clock mask was set successfully Function system_apb_clock_clear_mask() Clear bits in the clock mask for an APBx bus. enum status_code system_apb_clock_clear_mask( const enum system_clock_apb_bus bus, const uint32_t mask) This function will clear bits in the clock mask for an APBx bus. Any bits set to 1 will disable the corresponding module clock, zero bits in the mask will be ignored. Table 17-30. Parameters Returns Data direction Parameter name Description [in] mask APBx clock mask, a SYSTEM_CLOCK_APB_APBx constant from the device header files [in] bus Bus to clear clock mask bits Status indicating the result of the clock mask change operation. Table 17-31. Return Values Return value Description STATUS_ERR_INVALID_ARG Invalid bus ID was given STATUS_OK The clock mask was changed successfully 17.6.2.9 System Clock Initialization Function system_clock_init() Initialize clock system based on the configuration in conf_clocks.h. void system_clock_init(void) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 402 This function will apply the settings in conf_clocks.h when run from the user application. All clock sources and GCLK generators are running when this function returns. Note OSC8M is always enabled and if user selects other clocks for GCLK generators, the OSC8M default enable can be disabled after system_clock_init. Make sure the clock switch successfully before disabling OSC8M. 17.6.2.10 System Flash Wait States Function system_flash_set_waitstates() Set flash controller wait states. void system_flash_set_waitstates( uint8_t wait_states) Will set the number of wait states that are used by the onboard flash memory. The number of wait states depend on both device supply voltage and CPU speed. The required number of wait states can be found in the electrical characteristics of the device. Table 17-32. Parameters Data direction Parameter name Description [in] wait_states Number of wait states to use for internal flash 17.6.2.11 Generic Clock Management Function system_gclk_init() Initializes the GCLK driver. void system_gclk_init(void) Initializes the Generic Clock module, disabling and resetting all active Generic Clock Generators and Channels to their power-on default values. 17.6.2.12 Generic Clock Management (Generators) Function system_gclk_gen_get_config_defaults() Initializes a Generic Clock Generator configuration structure to defaults. void system_gclk_gen_get_config_defaults( struct system_gclk_gen_config *const config) Initializes a given Generic Clock Generator configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Clock is generated undivided from the source frequency AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 403 ● Clock generator output is low when the generator is disabled ● The input clock is sourced from input clock channel 0 ● Clock will be disabled during sleep ● The clock output will not be routed to a physical GPIO pin Table 17-33. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function system_gclk_gen_set_config() Writes a Generic Clock Generator configuration to the hardware module. void system_gclk_gen_set_config( const uint8_t generator, struct system_gclk_gen_config *const config) Writes out a given configuration of a Generic Clock Generator configuration to the hardware module. Note Changing the clock source on the fly (on a running generator) can take additional time if the clock source is configured to only run on-demand (ONDEMAND bit is set) and it is not currently running (no peripheral is requesting the clock source). In this case the GCLK will request the new clock while still keeping a request to the old clock source until the new clock source is ready. This function will not start a generator that is not already running; to start the generator, call system_gclk_gen_enable() after configuring a generator. Table 17-34. Parameters Data direction Parameter name Description [in] generator Generic Clock Generator index to configure [in] config Configuration settings for the generator Function system_gclk_gen_enable() Enables a Generic Clock Generator that was previously configured. void system_gclk_gen_enable( const uint8_t generator) Starts the clock generation of a Generic Clock Generator that was previously configured via a call to system_gclk_gen_set_config(). Table 17-35. Parameters Data direction Parameter name Description [in] generator Generic Clock Generator index to enable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 404 Function system_gclk_gen_disable() Disables a Generic Clock Generator that was previously enabled. void system_gclk_gen_disable( const uint8_t generator) Stops the clock generation of a Generic Clock Generator that was previously started via a call to system_gclk_gen_enable(). Table 17-36. Parameters Data direction Parameter name Description [in] generator Generic Clock Generator index to disable Function system_gclk_gen_is_enabled() Determins if the specified Generic Clock Generator is enabled. bool system_gclk_gen_is_enabled( const uint8_t generator) Table 17-37. Parameters Data direction Parameter name Description [in] generator Generic Clock Generator index to check Returns The enabled status. Table 17-38. Return Values Return value Description true The Generic Clock Generator is enabled false The Generic Clock Generator is disabled 17.6.2.13 Generic Clock Management (Channels) Function system_gclk_chan_get_config_defaults() Initializes a Generic Clock configuration structure to defaults. void system_gclk_chan_get_config_defaults( struct system_gclk_chan_config *const config) Initializes a given Generic Clock configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Clock is sourced from the Generic Clock Generator channel 0 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 405 ● Clock configuration will not be write-locked when set Table 17-39. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function system_gclk_chan_set_config() Writes a Generic Clock configuration to the hardware module. void system_gclk_chan_set_config( const uint8_t channel, struct system_gclk_chan_config *const config) Writes out a given configuration of a Generic Clock configuration to the hardware module. If the clock is currently running, it will be stopped. Note Once called the clock will not be running; to start the clock, call system_gclk_chan_enable() after configuring a clock channel. Table 17-40. Parameters Data direction Parameter name Description [in] channel Generic Clock channel to configure [in] config Configuration settings for the clock Function system_gclk_chan_enable() Enables a Generic Clock that was previously configured. void system_gclk_chan_enable( const uint8_t channel) Starts the clock generation of a Generic Clock that was previously configured via a call to system_gclk_chan_set_config(). Table 17-41. Parameters Data direction Parameter name Description [in] channel Generic Clock channel to enable Function system_gclk_chan_disable() Disables a Generic Clock that was previously enabled. void system_gclk_chan_disable( const uint8_t channel) Stops the clock generation of a Generic Clock that was previously started via a call to system_gclk_chan_enable(). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 406 Table 17-42. Parameters Data direction Parameter name Description [in] channel Generic Clock channel to disable Function system_gclk_chan_is_enabled() Determins if the specified Generic Clock channel is enabled. bool system_gclk_chan_is_enabled( const uint8_t channel) Table 17-43. Parameters Data direction Parameter name Description [in] channel Generic Clock Channel index Returns The enabled status. Table 17-44. Return Values Return value Description true The Generic Clock channel is enabled false The Generic Clock channel is disabled Function system_gclk_chan_lock() Locks a Generic Clock channel from further configuration writes. void system_gclk_chan_lock( const uint8_t channel) Locks a generic clock channel from further configuration writes. It is only possible to unlock the channel configuration through a power on reset. Table 17-45. Parameters Data direction Parameter name Description [in] channel Generic Clock channel to enable Function system_gclk_chan_is_locked() Determins if the specified Generic Clock channel is locked. bool system_gclk_chan_is_locked( const uint8_t channel) Table 17-46. Parameters Data direction Parameter name Description [in] channel Generic Clock Channel index AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 407 Returns The lock status. Table 17-47. Return Values Return value Description true The Generic Clock channel is locked false The Generic Clock channel is not locked 17.6.2.14 Generic Clock Frequency Retrieval Function system_gclk_gen_get_hz() Retrieves the clock frequency of a Generic Clock generator. uint32_t system_gclk_gen_get_hz( const uint8_t generator) Determines the clock frequency (in Hz) of a specified Generic Clock generator, used as a source to a Generic Clock Channel module. Table 17-48. Parameters Data direction Parameter name Description [in] generator Generic Clock Generator index Returns The frequency of the generic clock generator, in Hz. Function system_gclk_chan_get_hz() Retrieves the clock frequency of a Generic Clock channel. uint32_t system_gclk_chan_get_hz( const uint8_t channel) Determines the clock frequency (in Hz) of a specified Generic Clock channel, used as a source to a device peripheral module. Table 17-49. Parameters Returns 17.6.3 Data direction Parameter name Description [in] channel Generic Clock Channel index The frequency of the generic clock channel, in Hz. Enumeration Definitions 17.6.3.1 Enum gclk_generator AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 408 List of Available GCLK generators. This enum is used in the peripheral device drivers to select the GCLK generator to be used for its operation. The number of GCLK generators available is device dependent. Table 17-50. Members Enum value Description GCLK_GENERATOR_0 GCLK generator channel 0. GCLK_GENERATOR_1 GCLK generator channel 1. GCLK_GENERATOR_2 GCLK generator channel 2. GCLK_GENERATOR_3 GCLK generator channel 3. GCLK_GENERATOR_4 GCLK generator channel 4. GCLK_GENERATOR_5 GCLK generator channel 5. GCLK_GENERATOR_6 GCLK generator channel 6. GCLK_GENERATOR_7 GCLK generator channel 7. GCLK_GENERATOR_8 GCLK generator channel 8. GCLK_GENERATOR_9 GCLK generator channel 9. GCLK_GENERATOR_10 GCLK generator channel 10. GCLK_GENERATOR_11 GCLK generator channel 11. GCLK_GENERATOR_12 GCLK generator channel 12. GCLK_GENERATOR_13 GCLK generator channel 13. GCLK_GENERATOR_14 GCLK generator channel 14. GCLK_GENERATOR_15 GCLK generator channel 15. GCLK_GENERATOR_16 GCLK generator channel 16. 17.6.3.2 Enum system_clock_apb_bus Available bus clock domains on the APB bus. Table 17-51. Members Enum value Description SYSTEM_CLOCK_APB_APBA Peripheral bus A on the APB bus. SYSTEM_CLOCK_APB_APBB Peripheral bus B on the APB bus. SYSTEM_CLOCK_APB_APBC Peripheral bus C on the APB bus. 17.6.3.3 Enum system_clock_dfll_chill_cycle DFLL chill-cycle behavior modes of the DFLL module. A chill cycle is a period of time when the DFLL output frequency is not measured by the unit, to allow the output to stabilize after a change in the input clock source. Table 17-52. Members Enum value Description SYSTEM_CLOCK_DFLL_CHILL_CYCLE_ENABLE Enable a chill cycle, where the DFLL output frequency is not measured. SYSTEM_CLOCK_DFLL_CHILL_CYCLE_DISABLE Disable a chill cycle, where the DFLL output frequency is not measured. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 409 17.6.3.4 Enum system_clock_dfll_loop_mode Available operating modes of the DFLL clock source module. Table 17-53. Members Enum value Description SYSTEM_CLOCK_DFLL_LOOP_MODE_OPEN The DFLL is operating in open loop mode with no feedback. SYSTEM_CLOCK_DFLL_LOOP_MODE_CLOSED The DFLL is operating in closed loop mode with frequency feedback from a low frequency reference clock. 17.6.3.5 Enum system_clock_dfll_quick_lock DFLL QuickLock settings for the DFLL module, to allow for a faster lock of the DFLL output frequency at the expense of accuracy. Table 17-54. Members Enum value Description SYSTEM_CLOCK_DFLL_QUICK_LOCK_ENABLE Enable the QuickLock feature for looser lock requirements on the DFLL. SYSTEM_CLOCK_DFLL_QUICK_LOCK_DISABLE Disable the QuickLock feature for strict lock requirements on the DFLL. 17.6.3.6 Enum system_clock_dfll_stable_tracking DFLL fine tracking behavior modes after a lock has been acquired. Table 17-55. Members Enum value Description SYSTEM_CLOCK_DFLL_STABLE_TRACKING_TRACK_AFTER_LOCK Keep tracking after the DFLL has gotten a fine lock. SYSTEM_CLOCK_DFLL_STABLE_TRACKING_FIX_AFTER_LOCK Stop tracking after the DFLL has gotten a fine lock. 17.6.3.7 Enum system_clock_dfll_wakeup_lock DFLL lock behavior modes on device wake-up from sleep. Table 17-56. Members Enum value Description SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_KEEP Keep DFLL lock when the device wakes from sleep. SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_LOSE Lose DFLL lock when the devices wakes from sleep. 17.6.3.8 Enum system_clock_external AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 410 Available external clock source types. Table 17-57. Members Enum value Description SYSTEM_CLOCK_EXTERNAL_CRYSTAL The external clock source is a crystal oscillator. SYSTEM_CLOCK_EXTERNAL_CLOCK The connected clock source is an external logic level clock signal. 17.6.3.9 Enum system_clock_source Clock sources available to the GCLK generators. Table 17-58. Members Enum value Description SYSTEM_CLOCK_SOURCE_OSC8M Internal 8MHz RC oscillator. SYSTEM_CLOCK_SOURCE_OSC32K Internal 32KHz RC oscillator. SYSTEM_CLOCK_SOURCE_XOSC External oscillator. SYSTEM_CLOCK_SOURCE_XOSC32K External 32KHz oscillator. SYSTEM_CLOCK_SOURCE_DFLL Digital Frequency Locked Loop (DFLL). SYSTEM_CLOCK_SOURCE_ULP32K Internal Ultra Low Power 32KHz oscillator. SYSTEM_CLOCK_SOURCE_GCLKIN Generator input pad SYSTEM_CLOCK_SOURCE_GCLKGEN1 Generic clock generator one output 17.6.3.10 Enum system_main_clock_div Available division ratios for the CPU and APB/AHB bus clocks. Table 17-59. Members Enum value Description SYSTEM_MAIN_CLOCK_DIV_1 Divide Main clock by one. SYSTEM_MAIN_CLOCK_DIV_2 Divide Main clock by two. SYSTEM_MAIN_CLOCK_DIV_4 Divide Main clock by four. SYSTEM_MAIN_CLOCK_DIV_8 Divide Main clock by eight. SYSTEM_MAIN_CLOCK_DIV_16 Divide Main clock by 16. SYSTEM_MAIN_CLOCK_DIV_32 Divide Main clock by 32. SYSTEM_MAIN_CLOCK_DIV_64 Divide Main clock by 64. SYSTEM_MAIN_CLOCK_DIV_128 Divide Main clock by 128. 17.6.3.11 Enum system_osc32k_startup Available internal 32KHz oscillator start-up times, as a number of internal OSC32K clock cycles. Table 17-60. Members Enum value Description SYSTEM_OSC32K_STARTUP_3 Wait three clock cycles until the clock source is considered stable. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 411 Enum value Description SYSTEM_OSC32K_STARTUP_4 Wait four clock cycles until the clock source is considered stable. SYSTEM_OSC32K_STARTUP_6 Wait six clock cycles until the clock source is considered stable. SYSTEM_OSC32K_STARTUP_10 Wait ten clock cycles until the clock source is considered stable. SYSTEM_OSC32K_STARTUP_18 Wait 18 clock cycles until the clock source is considered stable. SYSTEM_OSC32K_STARTUP_34 Wait 34 clock cycles until the clock source is considered stable SYSTEM_OSC32K_STARTUP_66 Wait 66 clock cycles until the clock source is considered stable. SYSTEM_OSC32K_STARTUP_130 Wait 130 clock cycles until the clock source is considered stable. 17.6.3.12 Enum system_osc8m_div Available prescalers for the internal 8MHz (nominal) system clock. Table 17-61. Members Enum value Description SYSTEM_OSC8M_DIV_1 Do not divide the 8MHz RC oscillator output. SYSTEM_OSC8M_DIV_2 Divide the 8MHz RC oscillator output by two. SYSTEM_OSC8M_DIV_4 Divide the 8MHz RC oscillator output by four. SYSTEM_OSC8M_DIV_8 Divide the 8MHz RC oscillator output by eight. 17.6.3.13 Enum system_osc8m_frequency_range Internal 8MHz RC oscillator frequency range setting Table 17-62. Members Enum value Description SYSTEM_OSC8M_FREQUENCY_RANGE_4_TO_6 Frequency range 4MHz to 6MHz. SYSTEM_OSC8M_FREQUENCY_RANGE_6_TO_8 Frequency range 6MHz to 8MHz. SYSTEM_OSC8M_FREQUENCY_RANGE_8_TO_11 Frequency range 8MHz to 11MHz. SYSTEM_OSC8M_FREQUENCY_RANGE_11_TO_15 Frequency range 11MHz to 15MHz. 17.6.3.14 Enum system_xosc32k_startup Available external 32KHz oscillator start-up times, as a number of external clock cycles. Table 17-63. Members Enum value Description SYSTEM_XOSC32K_STARTUP_0 Wait zero clock cycles until the clock source is considered stable. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 412 Enum value Description SYSTEM_XOSC32K_STARTUP_32 Wait 32 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_2048 Wait 2048 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_4096 Wait 4096 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_16384 Wait 16384 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_32768 Wait 32768 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_65536 Wait 65536 clock cycles until the clock source is considered stable. SYSTEM_XOSC32K_STARTUP_131072 Wait 131072 clock cycles until the clock source is considered stable. 17.6.3.15 Enum system_xosc_startup Available external oscillator start-up times, as a number of external clock cycles. Table 17-64. Members Enum value Description SYSTEM_XOSC_STARTUP_1 Wait one clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_2 Wait two clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_4 Wait four clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_8 Wait eight clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_16 Wait 16 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_32 Wait 32 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_64 Wait 64 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_128 Wait 128 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_256 Wait 256 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_512 Wait 512 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_1024 Wait 1024 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_2048 Wait 2048 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_4096 Wait 4096 clock cycles until the clock source is considered stable. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 413 Enum value Description SYSTEM_XOSC_STARTUP_8192 Wait 8192 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_16384 Wait 16384 clock cycles until the clock source is considered stable. SYSTEM_XOSC_STARTUP_32768 Wait 32768 clock cycles until the clock source is considered stable. 17.7 Extra Information for SYSTEM CLOCK Driver 17.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 17.7.2 Acronym Description DFLL Digital Frequency Locked Loop MUX Multiplexer OSC32K Internal 32KHz Oscillator OSC8M Internal 8MHz Oscillator PLL Phase Locked Loop OSC Oscillator XOSC External Oscillator XOSC32K External 32KHz Oscillator AHB Advanced High-performance Bus APB Advanced Peripheral Bus DPLL Digital Phase Locked Loop Dependencies This driver has the following dependencies: ● 17.7.3 None Errata ● This driver implements workaround for errata 10558 "Several reset values of SYSCTRL.INTFLAG are wrong (BOD and DFLL)" When system_init is called it will reset these interrupts flags before they are used. ● This driver implements experimental workaround for errata 9905 "The DFLL clock must be requested before being configured otherwise a write access to a DFLL register can freeze the device." This driver will enable and configure the DFLL before the ONDEMAND bit is set. 17.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog ● Corrected OSC32K startup time definitions AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 414 Changelog ● Support locking of OSC32K and XOSC32K config register (default: false) ● Added DPLL support, functions added: system_clock_source_dpll_get_config_defaults() and system_clock_source_dpll_set_config() ● Moved gclk channel locking feature out of the config struct functions added: system_gclk_chan_lock(), system_gclk_chan_is_locked() system_gclk_chan_is_enabled() and system_gclk_gen_is_enabled() Fixed system_gclk_chan_disable() deadlocking if a channel is enabled and configured to a failed/not running clock generator ● Changed default value for CONF_CLOCK_DFLL_ON_DEMAND from true to false ● Fixed system_flash_set_waitstates() failing with an assertion if an odd number of wait states provided ● Updated dfll configuration function to implement workaround for errata 9905 in the DFLL module ● Updated system_clock_init() to reset interrupt flags before they are used, errata 10558 ● Fixed system_clock_source_get_hz() to return correcy DFLL frequency number ● Fixed system_clock_source_is_ready not returning the correct state for SYSTEM_CLOCK_SOURCE_OSC8M ● Renamed the various system_clock_source_*_get_default_config() functions to system_clock_source_*_get_config_defaults() to match the remainder of ASF ● Added OSC8M calibration constant loading from the device signature row when the oscillator is initialized ● Updated default configuration of the XOSC32 to disable Automatic Gain Control due to silicon errata Initial Release 17.8 Examples for System Clock Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM System Clock Management Driver (SYSTEM CLOCK). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_system_clock_basic_use_case ● asfdoc_sam0_system_gclk_basic_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 415 18. SAM System Driver (SYSTEM) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's system relation functionality, necessary for the basic device operation. This is not limited to a single peripheral, but extends across multiple hardware peripherals. The following peripherals are used by this module: ● SYSCTRL (System Control) ● PM (Power Manager) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 The outline of this documentation is as follows: 18.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 18.2 Module Overview The System driver provides a collection of interfaces between the user application logic, and the core device functionality (such as clocks, reset cause determination, etc.) that is required for all applications. It contains a number of sub-modules that control one specific aspect of the device: 18.2.1 ● System Core (this module) ● System Clock Control (sub-module) ● System Interrupt Control (sub-module) ● System Pin Multiplexer Control (sub-module) Voltage References The various analog modules within the SAM devices (such as AC, ADC, and DAC) require a voltage reference to be configured to act as a reference point for comparisons and conversions. The SAM devices contain multiple references, including an internal temperature sensor, and a fixed band-gap voltage source. When enabled, the associated voltage reference can be selected within the desired peripheral where applicable. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 416 18.2.2 System Reset Cause In some applications there may be a need to execute a different program flow based on how the device was reset. For example, if the cause of reset was the Watchdog timer (WDT), this might indicate an error in the application and a form of error handling or error logging might be needed. For this reason, an API is provided to retrieve the cause of the last system reset, so that appropriate action can be taken. 18.2.3 Sleep Modes The SAM devices have several sleep modes, where the sleep mode controls which clock systems on the device will remain enabled or disabled when the device enters a low power sleep mode. Table 18-1: SAM Device Sleep Modes on page 417 lists the clock settings of the different sleep modes. Table 18-1. SAM Device Sleep Modes Sleep mode CPU clock AHB clock APB clocks Clock sources System clock 32KHz Reg mode RAM mode IDLE 0 Stop Run Run Run Run Run Normal Normal IDLE 1 Stop Stop Run Run Run Run Normal Normal IDLE 2 Stop Stop Stop Run Run Run Normal Normal STANDBY Stop Stop Stop Stop Stop Stop Low Power Source/ Drain biasing To enter device sleep, one of the available sleep modes must be set, and the function to enter sleep called. The device will automatically wake up in response to an interrupt being generated or other device event. Some peripheral clocks will remain enabled during sleep, depending on their configuration; if desired, modules can remain clocked during sleep to allow them to continue to operate while other parts of the system are powered down to save power. 18.3 Special Considerations Most of the functions in this driver have device specific restrictions and caveats; refer to your device datasheet. 18.4 Extra Information For extra information, see Extra Information for SYSTEM Driver. This includes: 18.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For SYSTEM module related examples, refer to the sub-modules listed in the system module overview. 18.6 API Overview 18.6.1 Function Definitions 18.6.1.1 System Debugger Function system_is_debugger_present() Check if debugger is present. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 417 bool system_is_debugger_present(void) Check if debugger is connected to the onboard debug system (DAP). Returns A bool identifying if a debugger is present. Table 18-2. Return Values Return value Description true Debugger is connected to the system false Debugger is not connected to the system 18.6.1.2 System Identification Function system_get_device_id() Retrieve the device identification signature. uint32_t system_get_device_id(void) Retrieves the signature of the current device. Returns Device ID signature as a 32-bit integer. 18.6.1.3 System Initialization Function system_init() Initialize system. void system_init(void) This function will call the various initialization functions within the system namespace. If a given optional system module is not available, the associated call will effectively be a NOP (No Operation). Currently the following initialization functions are supported: ● System clock initialization (via the SYSTEM CLOCK sub-module) ● Board hardware initialization (via the Board module) ● Event system driver initialization (via the EVSYS module) ● External Interrupt driver initialization (via the EXTINT module) 18.6.1.4 Voltage References Function system_voltage_reference_enable() Enable the selected voltage reference. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 418 void system_voltage_reference_enable( const enum system_voltage_reference vref) Enables the selected voltage reference source, making the voltage reference available on a pin as well as an input source to the analog peripherals. Table 18-3. Parameters Data direction Parameter name Description [in] vref Voltage reference to enable Function system_voltage_reference_disable() Disable the selected voltage reference. void system_voltage_reference_disable( const enum system_voltage_reference vref) Disables the selected voltage reference source. Table 18-4. Parameters Data direction Parameter name Description [in] vref Voltage reference to disable 18.6.1.5 Device Sleep Control Function system_set_sleepmode() Set the sleep mode of the device. enum status_code system_set_sleepmode( const enum system_sleepmode sleep_mode) Sets the sleep mode of the device; the configured sleep mode will be entered upon the next call of the system_sleep() function. For an overview of which systems are disabled in sleep for the different sleep modes, see Sleep Modes. Table 18-5. Parameters Data direction Parameter name Description [in] sleep_mode Sleep mode to configure for the next sleep operation Table 18-6. Return Values Return value Description STATUS_OK Operation completed successfully STATUS_ERR_INVALID_ARG The requested sleep mode was invalid or not available Function system_sleep() Put the system to sleep waiting for interrupt. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 419 void system_sleep(void) Executes a device DSB (Data Synchronization Barrier) instruction to ensure all ongoing memory accesses have completed, then a WFI (Wait For Interrupt) instruction to place the device into the sleep mode specified by system_set_sleepmode until woken by an interrupt. 18.6.1.6 Reset Control Function system_reset() Reset the MCU. void system_reset(void) Resets the MCU and all associated peripherals and registers, except RTC, all 32kHz sources, WDT (if ALWAYSON is set) and GCLK (if WRTLOCK is set). Function system_get_reset_cause() Return the reset cause. enum system_reset_cause system_get_reset_cause(void) Retrieves the cause of the last system reset. Returns 18.6.2 An enum value indicating the cause of the last system reset. Enumeration Definitions 18.6.2.1 Enum system_reset_cause List of possible reset causes of the system. Table 18-7. Members Enum value Description SYSTEM_RESET_CAUSE_SOFTWARE The system was last reset by a software reset. SYSTEM_RESET_CAUSE_WDT The system was last reset by the watchdog timer. SYSTEM_RESET_CAUSE_EXTERNAL_RESET The system was last reset because the external reset line was pulled low. SYSTEM_RESET_CAUSE_BOD33 The system was last reset by the BOD33. SYSTEM_RESET_CAUSE_BOD12 The system was last reset by the BOD12. SYSTEM_RESET_CAUSE_POR The system was last reset by the POR (Power on reset). 18.6.2.2 Enum system_sleepmode AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 420 List of available sleep modes in the device. A table of clocks available in different sleep modes can be found in Sleep Modes. Table 18-8. Members Enum value Description SYSTEM_SLEEPMODE_IDLE_0 IDLE 0 sleep mode. SYSTEM_SLEEPMODE_IDLE_1 IDLE 1 sleep mode. SYSTEM_SLEEPMODE_IDLE_2 IDLE 2 sleep mode. SYSTEM_SLEEPMODE_STANDBY Standby sleep mode. 18.6.2.3 Enum system_voltage_reference List of available voltage references (VREF) that may be used within the device. Table 18-9. Members Enum value Description SYSTEM_VOLTAGE_REFERENCE_TEMPSENSE Temperature sensor voltage reference. SYSTEM_VOLTAGE_REFERENCE_BANDGAP Bandgap voltage reference. 18.7 Extra Information for SYSTEM Driver 18.7.1 Acronyms Below is a table listing the acronyms used in this module, along with their intended meanings. 18.7.2 Acronym Definition PM Power Manager SYSCTRL System control interface Dependencies This driver has the following dependencies: ● 18.7.3 None Errata There are no errata related to this driver. 18.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added low power features and support for SAML21 Added support for SAMD21 Added new system_reset() to reset the complete MCU with some exceptions Added new system_get_device_id() function to retrieved the device ID. Initial Release AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 421 19. SAM System Interrupt Driver (SYSTEM INTERRUPT) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of internal software and hardware interrupts/exceptions. The following peripherals are used by this module: ● NVIC (Nested Vector Interrupt Controller) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 19.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 19.2 Module Overview ® ® The ARM Cortex M0+ core contains an interrupt and exception vector table, which can be used to configure the device's interrupt handlers; individual interrupts and exceptions can be enabled and disabled, as well as configured with a variable priority. This driver provides a set of wrappers around the core interrupt functions, to expose a simple API for the management of global and individual interrupts within the device. 19.2.1 Critical Sections In some applications it is important to ensure that no interrupts may be executed by the system whilst a critical portion of code is being run; for example, a buffer may be copied from one context to another - during which interrupts must be disabled to avoid corruption of the source buffer contents until the copy has completed. This driver provides a basic API to enter and exit nested critical sections, so that global interrupts can be kept disabled for as long as necessary to complete a critical application code section. 19.2.2 Software Interrupts For some applications, it may be desirable to raise a module or core interrupt via software. For this reason, a set of APIs to set an interrupt or exception as pending are provided to the user application. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 422 19.3 Special Considerations Interrupts from peripherals in the SAM devices are on a per-module basis; an interrupt raised from any source within a module will cause a single, module-common handler to execute. It is the user application or driver's responsibility to de-multiplex the module-common interrupt to determine the exact interrupt cause. 19.4 Extra Information For extra information, see Extra Information for SYSTEM INTERRUPT Driver. This includes: 19.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for SYSTEM INTERRUPT Driver. 19.6 API Overview 19.6.1 Function Definitions 19.6.1.1 Critical Section Management Function system_interrupt_enter_critical_section() Enters a critical section. void system_interrupt_enter_critical_section(void) Disables global interrupts. To support nested critical sections, an internal count of the critical section nesting will be kept, so that global interrupts are only re-enabled upon leaving the outermost nested critical section. Function system_interrupt_leave_critical_section() Leaves a critical section. void system_interrupt_leave_critical_section(void) Enables global interrupts. To support nested critical sections, an internal count of the critical section nesting will be kept, so that global interrupts are only re-enabled upon leaving the outermost nested critical section. 19.6.1.2 Interrupt Enabling/Disabling Function system_interrupt_is_global_enabled() Check if global interrupts are enabled. bool system_interrupt_is_global_enabled(void) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 423 Checks if global interrupts are currently enabled. Returns A boolean that identifies if the global interrupts are enabled or not. Table 19-1. Return Values Return value Description true Global interrupts are currently enabled false Global interrupts are currently disabled Function system_interrupt_enable_global() Enables global interrupts. void system_interrupt_enable_global(void) Enables global interrupts in the device to fire any enabled interrupt handlers. Function system_interrupt_disable_global() Disables global interrupts. void system_interrupt_disable_global(void) Disabled global interrupts in the device, preventing any enabled interrupt handlers from executing. Function system_interrupt_is_enabled() Checks if an interrupt vector is enabled or not. bool system_interrupt_is_enabled( const enum system_interrupt_vector vector) Checks if a specific interrupt vector is currently enabled. Table 19-2. Parameters Data direction Parameter name Description [in] vector Interrupt vector number to check Returns A variable identifying if the requested interrupt vector is enabled. Table 19-3. Return Values Return value Description true Specified interrupt vector is currently enabled false Specified interrupt vector is currently disabled AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 424 Function system_interrupt_enable() Enable interrupt vector. void system_interrupt_enable( const enum system_interrupt_vector vector) Enables execution of the software handler for the requested interrupt vector. Table 19-4. Parameters Data direction Parameter name Description [in] vector Interrupt vector to enable Function system_interrupt_disable() Disable interrupt vector. void system_interrupt_disable( const enum system_interrupt_vector vector) Disables execution of the software handler for the requested interrupt vector. Table 19-5. Parameters Data direction Parameter name Description [in] vector Interrupt vector to disable 19.6.1.3 Interrupt State Management Function system_interrupt_get_active() Get active interrupt (if any). enum system_interrupt_vector system_interrupt_get_active(void) Return the vector number for the current executing software handler, if any. Returns Interrupt number that is currently executing. Function system_interrupt_is_pending() Check if a interrupt line is pending. bool system_interrupt_is_pending( const enum system_interrupt_vector vector) 2 Support and FAQ: visit Atmel Support Checks if the requested interrupt vector is pending. 2 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 425 Table 19-6. Parameters Data direction Parameter name Description [in] vector Interrupt vector number to check Returns A boolean identifying if the requested interrupt vector is pending. Table 19-7. Return Values Return value Description true Specified interrupt vector is pending false Specified interrupt vector is not pending Function system_interrupt_set_pending() Set a interrupt vector as pending. enum status_code system_interrupt_set_pending( const enum system_interrupt_vector vector) Set the requested interrupt vector as pending (i.e issues a software interrupt request for the specified vector). The software handler will be handled (if enabled) in a priority order based on vector number and configured priority settings. Table 19-8. Parameters Data direction Parameter name Description [in] vector Interrupt vector number which is set as pending Returns Status code identifying if the vector was successfully set as pending. Table 19-9. Return Values Return value Description STATUS_OK If no error was detected STATUS_INVALID_ARG If an unsupported interrupt vector number was given Function system_interrupt_clear_pending() Clear pending interrupt vector. enum status_code system_interrupt_clear_pending( const enum system_interrupt_vector vector) Clear a pending interrupt vector, so the software handler is not executed. Table 19-10. Parameters Data direction Parameter name Description [in] vector Interrupt vector number to clear AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 426 Returns A status code identifying if the interrupt pending state was successfully cleared. Table 19-11. Return Values Return value Description STATUS_OK If no error was detected STATUS_INVALID_ARG If an unsupported interrupt vector number was given 19.6.1.4 Interrupt Priority Management Function system_interrupt_set_priority() Set interrupt vector priority level. enum status_code system_interrupt_set_priority( const enum system_interrupt_vector vector, const enum system_interrupt_priority_level priority_level) Set the priority level of an external interrupt or exception. Table 19-12. Parameters Data direction Parameter name Description [in] vector Interrupt vector to change [in] priority_level New vector priority level to set Returns Status code indicating if the priority level of the interrupt was successfully set. Table 19-13. Return Values Return value Description STATUS_OK If no error was detected STATUS_INVALID_ARG If an unsupported interrupt vector number was given Function system_interrupt_get_priority() Get interrupt vector priority level. enum system_interrupt_priority_level system_interrupt_get_priority( const enum system_interrupt_vector vector) Retrieves the priority level of the requested external interrupt or exception. Table 19-14. Parameters Data direction Parameter name Description [in] vector Interrupt vector of which the priority level will be read AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 427 Returns 19.6.2 Currently configured interrupt priority level of the given interrupt vector. Enumeration Definitions 19.6.2.1 Enum system_interrupt_priority_level Table of all possible interrupt and exception vector priorities within the device. Table 19-15. Members Enum value Description SYSTEM_INTERRUPT_PRIORITY_LEVEL_0 Priority level 0, the highest possible interrupt priority. SYSTEM_INTERRUPT_PRIORITY_LEVEL_1 Priority level 1. SYSTEM_INTERRUPT_PRIORITY_LEVEL_2 Priority level 2. SYSTEM_INTERRUPT_PRIORITY_LEVEL_3 Priority level 3, the lowest possible interrupt priority. 19.6.2.2 Enum system_interrupt_vector_samd1x Table of all possible interrupt and exception vector indexes within the SAMD1x device. Note The actual enumeration name is "system_interrupt_vector". Table 19-16. Members Enum value Description SYSTEM_INTERRUPT_NON_MASKABLE Interrupt vector index for a NMI interrupt. SYSTEM_INTERRUPT_HARD_FAULT Interrupt vector index for a Hard Fault memory access exception. SYSTEM_INTERRUPT_SV_CALL Interrupt vector index for a Supervisor Call exception. SYSTEM_INTERRUPT_PENDING_SV Interrupt vector index for a Pending Supervisor interrupt. SYSTEM_INTERRUPT_SYSTICK Interrupt vector index for a System Tick interrupt. SYSTEM_INTERRUPT_MODULE_PM Interrupt vector index for a Power Manager peripheral interrupt. SYSTEM_INTERRUPT_MODULE_SYSCTRL Interrupt vector index for a System Control peripheral interrupt. SYSTEM_INTERRUPT_MODULE_WDT Interrupt vector index for a Watch Dog peripheral interrupt. SYSTEM_INTERRUPT_MODULE_RTC Interrupt vector index for a Real Time Clock peripheral interrupt. SYSTEM_INTERRUPT_MODULE_EIC Interrupt vector index for an External Interrupt peripheral interrupt. SYSTEM_INTERRUPT_MODULE_NVMCTRL Interrupt vector index for a Non Volatile Memory Controller interrupt. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 428 Enum value Description SYSTEM_INTERRUPT_MODULE_DMA Interrupt vector index for a Direct Memory Access interrupt. SYSTEM_INTERRUPT_MODULE_EVSYS Interrupt vector index for an Event System interrupt. SYSTEM_INTERRUPT_MODULE_SERCOMn Interrupt vector index for a SERCOM peripheral interrupt. Each specific device may contain several SERCOM peripherals; each module instance will have its own entry in the table, with the instance number substituted for "n" in the entry name (e.g. SYSTEM_INTERRUPT_MODULE_SERCOM0). SYSTEM_INTERRUPT_MODULE_TCCn Interrupt vector index for a Timer/Counter Control peripheral interrupt. Each specific device may contain several TCC peripherals; each module instance will have its own entry in the table, with the instance number substituted for "n" in the entry name (e.g. SYSTEM_INTERRUPT_MODULE_TCC0). SYSTEM_INTERRUPT_MODULE_TCn Interrupt vector index for a Timer/Counter peripheral interrupt. Each specific device may contain several TC peripherals; each module instance will have its own entry in the table, with the instance number substituted for "n" in the entry name (e.g. SYSTEM_INTERRUPT_MODULE_TC3). SYSTEM_INTERRUPT_MODULE_AC Interrupt vector index for an Analog Comparator peripheral interrupt. SYSTEM_INTERRUPT_MODULE_ADC Interrupt vector index for an Analog-to-Digital peripheral interrupt. SYSTEM_INTERRUPT_MODULE_DAC Interrupt vector index for a Digital-to-Analog peripheral interrupt. SYSTEM_INTERRUPT_MODULE_PTC Interrupt vector index for a Peripheral Touch Controller peripheral interrupt. 19.7 Extra Information for SYSTEM INTERRUPT Driver 19.7.1 Acronyms The table below presents the acronyms used in this module: 19.7.2 Acronym Description ISR Interrupt Service Routine NMI Non-maskable Interrupt SERCOM Serial Communication Interface Dependencies This driver has the following dependencies: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 429 ● 19.7.3 None Errata There are no errata related to this driver. 19.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAML21 Added support for SAMD10/D11 Added support for SAMR21 Added support for SAMD21 Initial Release 19.8 Examples for SYSTEM INTERRUPT Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM System Interrupt Driver (SYSTEM INTERRUPT). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_system_interrupt_critsec_use_case ● asfdoc_sam0_system_interrupt_enablemodint_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 430 20. SAM System Pin Multiplexer Driver (SYSTEM PINMUX) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's physical I/O Pins, to alter the direction and input/drive characteristics as well as to configure the pin peripheral multiplexer selection. The following peripherals are used by this module: ● PORT (Port I/O Management) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 Physically, the modules are interconnected within the device as shown in the following diagram: The outline of this documentation is as follows: 20.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 20.2 Module Overview The SAM devices contain a number of General Purpose I/O pins, used to interface the user application logic and internal hardware peripherals to an external system. The Pin Multiplexer (PINMUX) driver provides a method of configuring the individual pin peripheral multiplexers to select alternate pin functions. 20.2.1 Driver Feature Macro Definition Note 20.2.2 Driver Feature Macro Supported devices FEATURE_SYSTEM_PINMUX_DRIVE_STRENGTH SAML21 The specific features are only available in the driver when the selected device supports those features. Physical and Logical GPIO Pins SAM devices use two naming conventions for the I/O pins in the device; one physical and one logical. Each physical pin on a device package is assigned both a physical port and pin identifier (e.g. "PORTA.0") as well as a monotonically incrementing logical GPIO number (e.g. "GPIO0"). While the former is used to map physical pins 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 431 to their physical internal device module counterparts, for simplicity the design of this driver uses the logical GPIO numbers instead. 20.2.3 Peripheral Multiplexing SAM devices contain a peripheral MUX, which is individually controllable for each I/O pin of the device. The peripheral MUX allows you to select the function of a physical package pin - whether it will be controlled as a user controllable GPIO pin, or whether it will be connected internally to one of several peripheral modules (such as an 2 I C module). When a pin is configured in GPIO mode, other peripherals connected to the same pin will be disabled. 20.2.4 Special Pad Characteristics There are several special modes that can be selected on one or more I/O pins of the device, which alter the input and output characteristics of the pad. 20.2.4.1 Drive Strength The Drive Strength configures the strength of the output driver on the pad. Normally, there is a fixed current limit that each I/O pin can safely drive, however some I/O pads offer a higher drive mode which increases this limit for that I/O pin at the expense of an increased power consumption. 20.2.4.2 Slew Rate The Slew Rate configures the slew rate of the output driver, limiting the rate at which the pad output voltage can change with time. 20.2.4.3 Input Sample Mode The Input Sample Mode configures the input sampler buffer of the pad. By default, the input buffer is only sampled "on-demand", i.e. when the user application attempts to read from the input buffer. This mode is the most power efficient, but increases the latency of the input sample by two clock cycles of the port clock. To reduce latency, the input sampler can instead be configured to always sample the input buffer on each port clock cycle, at the expense of an increased power consumption. 20.2.5 Physical Connection Figure 20-1: Physical Connection on page 432 shows how this module is interconnected within the device: Figure 20-1. Physical Connection Por t Pa d P e r ip h e r a l M U X GP IO M o d u le 20.3 Ot h e r P e r ip h e r a l M o d u le s Special Considerations The SAM port pin input sampling mode is set in groups of four physical pins; setting the sampling mode of any pin in a sub-group of eight I/O pins will configure the sampling mode of the entire sub-group. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 432 High Drive Strength output driver mode is not available on all device pins - refer to your device specific datasheet. 20.4 Extra Information For extra information, see Extra Information for SYSTEM PINMUX Driver. This includes: 20.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for SYSTEM PINMUX Driver. 20.6 API Overview 20.6.1 Structure Definitions 20.6.1.1 Struct system_pinmux_config Configuration structure for a port pin instance. This structure should be structure should be initialized by the system_pinmux_get_config_defaults() function before being modified by the user application. Table 20-1. Members Type Name Description enum system_pinmux_pin_dir direction Port buffer input/output direction. enum system_pinmux_pin_pull input_pull Logic level pull of the input buffer. uint8_t mux_position MUX index of the peripheral that should control the pin, if peripheral control is desired. For GPIO use, this should be set to SYSTEM_PINMUX_GPIO. bool powersave Enable lowest possible powerstate 1 on the pin. Notes: 20.6.2 1 All other configurations will be ignored, the pin will be disabled. Macro Definitions 20.6.2.1 Macro SYSTEM_PINMUX_GPIO #define SYSTEM_PINMUX_GPIO (1 << 7) Peripheral multiplexer index to select GPIO mode for a pin. 20.6.3 Function Definitions 20.6.3.1 Configuration and Initialization Function system_pinmux_get_config_defaults() Initializes a Port pin configuration structure to defaults. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 433 void system_pinmux_get_config_defaults( struct system_pinmux_config *const config) Initializes a given Port pin configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Non peripheral (i.e. GPIO) controlled ● Input mode with internal pull-up enabled Table 20-2. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function system_pinmux_pin_set_config() Writes a Port pin configuration to the hardware module. void system_pinmux_pin_set_config( const uint8_t gpio_pin, const struct system_pinmux_config *const config) Writes out a given configuration of a Port pin configuration to the hardware module. Note If the pin direction is set as an output, the pull-up/pull-down input configuration setting is ignored. Table 20-3. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to configure [in] config Configuration settings for the pin Function system_pinmux_group_set_config() Writes a Port pin group configuration to the hardware module. void system_pinmux_group_set_config( PortGroup *const port, const uint32_t mask, const struct system_pinmux_config *const config) Writes out a given configuration of a Port pin group configuration to the hardware module. Note If the pin direction is set as an output, the pull-up/pull-down input configuration setting is ignored. Table 20-4. Parameters Data direction Parameter name Description [in] port Base of the PORT module to configure AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 434 Data direction Parameter name Description [in] mask Mask of the port pin(s) to configure [in] config Configuration settings for the pin 20.6.3.2 Special Mode Configuration (Physical Group Orientated) Function system_pinmux_get_group_from_gpio_pin() Retrieves the PORT module group instance from a given GPIO pin number. PortGroup * system_pinmux_get_group_from_gpio_pin( const uint8_t gpio_pin) Retrieves the PORT module group instance associated with a given logical GPIO pin number. Table 20-5. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to convert Returns Base address of the associated PORT module. Function system_pinmux_group_set_input_sample_mode() Configures the input sampling mode for a group of pins. void system_pinmux_group_set_input_sample_mode( PortGroup *const port, const uint32_t mask, const enum system_pinmux_pin_sample mode) Configures the input sampling mode for a group of pins, to control when the physical I/O pin value is sampled and stored inside the microcontroller. Table 20-6. Parameters Data direction Parameter name Description [in] port Base of the PORT module to configure [in] mask Mask of the port pin(s) to configure [in] mode New pin sampling mode to configure 20.6.3.3 Special Mode Configuration (Logical Pin Orientated) Function system_pinmux_pin_get_mux_position() Retrieves the currently selected MUX position of a logical pin. uint8_t system_pinmux_pin_get_mux_position( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 435 const uint8_t gpio_pin) Retrieves the selected MUX peripheral on a given logical GPIO pin. Table 20-7. Parameters Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to configure Returns Currently selected peripheral index on the specified pin. Function system_pinmux_pin_set_input_sample_mode() Configures the input sampling mode for a GPIO pin. void system_pinmux_pin_set_input_sample_mode( const uint8_t gpio_pin, const enum system_pinmux_pin_sample mode) Configures the input sampling mode for a GPIO input, to control when the physical I/O pin value is sampled and stored inside the microcontroller. Table 20-8. Parameters 20.6.4 Data direction Parameter name Description [in] gpio_pin Index of the GPIO pin to configure [in] mode New pin sampling mode to configure Enumeration Definitions 20.6.4.1 Enum system_pinmux_pin_dir Enum for the possible pin direction settings of the port pin configuration structure, to indicate the direction the pin should use. Table 20-9. Members Enum value Description SYSTEM_PINMUX_PIN_DIR_INPUT The pin's input buffer should be enabled, so that the pin state can be read. SYSTEM_PINMUX_PIN_DIR_OUTPUT The pin's output buffer should be enabled, so that the pin state can be set (but not read back). SYSTEM_PINMUX_PIN_DIR_OUTPUT_WITH_READBACK The pin's output and input buffers should both be enabled, so that the pin state can be set and read back. 20.6.4.2 Enum system_pinmux_pin_pull Enum for the possible pin pull settings of the port pin configuration structure, to indicate the type of logic level pull the pin should use. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 436 Table 20-10. Members Enum value Description SYSTEM_PINMUX_PIN_PULL_NONE No logical pull should be applied to the pin. SYSTEM_PINMUX_PIN_PULL_UP Pin should be pulled up when idle. SYSTEM_PINMUX_PIN_PULL_DOWN Pin should be pulled down when idle. 20.6.4.3 Enum system_pinmux_pin_sample Enum for the possible input sampling modes for the port pin configuration structure, to indicate the type of sampling a port pin should use. Table 20-11. Members Enum value Description SYSTEM_PINMUX_PIN_SAMPLE_CONTINUOUS Pin input buffer should continuously sample the pin state. SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND Pin input buffer should be enabled when the IN register is read. 20.7 Extra Information for SYSTEM PINMUX Driver 20.7.1 Acronyms The table below presents the acronyms used in this module: 20.7.2 Acronym Description GPIO General Purpose Input/Output MUX Multiplexer Dependencies This driver has the following dependencies: ● 20.7.3 None Errata There are no errata related to this driver. 20.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add SAML21 support. Removed code of open drain, slew limit and drive strength features Fixed broken sampling mode function implementations, which wrote corrupt configuration values to the device registers Added missing NULL pointer asserts to the PORT driver functions Initial Release AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 437 20.8 Examples for SYSTEM PINMUX Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM System Pin Multiplexer Driver (SYSTEM PINMUX). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● 20.8.1 Quick Start Guide for SYSTEM PINMUX - Basic Quick Start Guide for SYSTEM PINMUX - Basic In this use case, the PINMUX module is configured for: ● One pin in input mode, with pull-up enabled, connected to the GPIO module ● Sampling mode of the pin changed to sample on demand This use case sets up the PINMUX to configure a physical I/O pin set as an input with pull-up and changes the sampling mode of the pin to reduce power by only sampling the physical pin state when the user application attempts to read it. 20.8.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your application: struct system_pinmux_config config_pinmux; system_pinmux_get_config_defaults(&config_pinmux); config_pinmux.mux_position = SYSTEM_PINMUX_GPIO; config_pinmux.direction = SYSTEM_PINMUX_PIN_DIR_INPUT; config_pinmux.input_pull = SYSTEM_PINMUX_PIN_PULL_UP; system_pinmux_pin_set_config(10, &config_pinmux); Workflow 1. Create a PINMUX module pin configuration struct, which can be filled out to adjust the configuration of a single port pin. struct system_pinmux_config config_pinmux; 2. Initialize the pin configuration struct with the module's default values. system_pinmux_get_config_defaults(&config_pinmux); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to request an input pin with pullup connected to the GPIO peripheral. config_pinmux.mux_position = SYSTEM_PINMUX_GPIO; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 438 config_pinmux.direction config_pinmux.input_pull 4. = SYSTEM_PINMUX_PIN_DIR_INPUT; = SYSTEM_PINMUX_PIN_PULL_UP; Configure GPIO10 with the initialized pin configuration struct, to enable the input sampler on the pin. system_pinmux_pin_set_config(10, &config_pinmux); 20.8.1.2 Use Case Code Copy-paste the following code to your user application: system_pinmux_pin_set_input_sample_mode(10, SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND); while (true) { /* Infinite loop */ } Workflow 1. Adjust the configuration of the pin to enable on-demand sampling mode. system_pinmux_pin_set_input_sample_mode(10, SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 439 21. SAM Timer Counter for Control Applications Driver (TCC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the TCC module within the device, for waveform generation and timing operations. It also provides extended options for control applications. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● TCC (Timer/Counter for Control Applications) The following devices can use this module: ● Atmel | SMART SAM D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 21.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 21.2 Module Overview The Timer/Counter for Control Applications (TCC) module provides a set of timing and counting related functionality, such as the generation of periodic waveforms, the capturing of a periodic waveform's frequency/duty cycle, software timekeeping for periodic operations, waveform extension control, fault detection etc. The counter size of the TCC modules can be 16- or 24-bit depending on the TCC instance. Refer SAM TCC Feature List and SAM D10/D11 TCC Feature List for details on TCC instances. The TCC module for the SAM includes the following functions: ● Generation of PWM signals ● Generation of timestamps for events 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 440 ● General time counting ● Waveform period capture ● Waveform frequency capture ● Additional control for generated waveform outputs ● Fault protection for waveform generation Figure 21-1: Overview of the TCC Module on page 441 shows the overview of the TCC Module. Figure 21-1. Overview of the TCC Module Base Counter PERB PER Prescaler "count" "clear" "load" "direction" Counter COUNT = Control Logic TOP BOTTOM =0 OVF (INT/Event/DMA Req.) ERR (INT Req.) "ev" UPDATE BV "TCCx_EV0" "TCCx_EV1" "TCCx_MCx" Event System WO[7] = 21.2.1 Waveform Generation "match" Non-recoverable Faults SWAP Control Logic Dead-Time Insertion CCx Output Matrix CCBx Recoverable Faults BV "capture" Pattern Generation WO[6] Compare/Capture (Unit x = {0,1,…,3}) WO[5] WO[4] WO[3] WO[2] WO[1] WO[0] MCx (INT/Event/DMA Req.) Functional Description The TCC module consists of following sections: ● Base Counter ● Compare/Capture channels, with waveform generation ● Waveform extension control and fault detection ● Interface to the event system, DMAC, and the interrupt system The base counter can be configured to either count a prescaled generic clock or events from the event system. (TCEx, with event action configured to counting). The counter value can be used by compare/capture channels which can be set up either in compare mode or capture mode. In capture mode, the counter value is stored when a configurable event occurs. This mode can be used to generate timestamps used in event capture, or it can be used for the measurement of a periodic input signal's frequency/duty cycle. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 441 In compare mode, the counter value is compared against one or more of the configured channels' compare values. When the counter value coincides with a compare value an action can be taken automatically by the module, such as generating an output event or toggling a pin when used for frequency or PWM signal generation. Note The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. In compare mode, when output signal is generated, extended waveform controls are available, to arrange the compare outputs into specific formats. The Output matrix can change the channel output routing. Pattern generation unit can overwrite the output signal line to specific state. The Fault protection feature of the TCC supports recoverable and non-recoverable faults. 21.2.2 Base Timer/Counter 21.2.2.1 Timer/Counter Size Each TCC has a counter size of either 16- or 24-bits. The size of the counter determines the maximum value it can count to before an overflow occurs. Table 21-1: Timer Counter Sizes and Their Maximum Count Values on page 442 shows the maximum values for each of the possible counter sizes. Table 21-1. Timer Counter Sizes and Their Maximum Count Values Counter size Max. (hexadecimal) Max. (decimal) 16-bit 0xFFFF 65,535 24-bit 0xFFFFFF 16,777,215 The period/top value of the counter can be set, to define counting period. This will allow the counter to overflow when the counter value reaches the period/top value. 21.2.2.2 Timer/Counter Clock and Prescaler TCC is clocked asynchronously to the system clock by a GCLK (Generic Clock) channel. The GCLK channel can be connected to any of the GCLK generators. The GCLK generators are configured to use one of the available clock sources in the system such as internal oscillator, external crystals, etc. - see the Generic Clock driver for more information. Each TCC module in the SAM has its own individual clock prescaler, which can be used to divide the input clock frequency used by the counter. This prescaler only scales the clock used to provide clock pulses for the counter to count, and does not affect the digital register interface portion of the module, thus the timer registers will synchronized to the raw GCLK frequency input to the module. As a result of this, when selecting a GCLK frequency and timer prescaler value the user application should consider both the timer resolution required and the synchronization frequency, to avoid lengthy synchronization times of the module if a very slow GCLK frequency is fed into the TCC module. It is preferable to use a higher module GCLK frequency as the input to the timer and prescale this down as much as possible to obtain a suitable counter frequency in latency-sensitive applications. 21.2.2.3 Timer/Counter Control Inputs (Events) The TCC can take several actions on the occurrence of an input event. The event actions are listed in Table 21-2: TCC Module Event Actions on page 442. Table 21-2. TCC Module Event Actions Event action Description Applied event TCC_EVENT_ACTION_OFF No action on the event input All AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 442 Event action Description Applied event TCC_EVENT_ACTION_RETRIGGER Re-trigger Counter on event All TCC_EVENT_ACTION_NON_RECOVERABLE_FAULT Generate Non-Recoverable Fault on event All TCC_EVENT_ACTION_START EV0 Counter start on event TCC_EVENT_ACTION_DIR_CONTROL Counter direction control EV0 TCC_EVENT_ACTION_DECREMENTCounter decrement on event EV0 TCC_EVENT_ACTION_PERIOD_PULSE_WIDTH_CAPTURE Capture pulse period and pulse width EV0 TCC_EVENT_ACTION_PULSE_WIDTH_PERIOD_CAPTURE Capture pulse width and pulse period EV0 TCC_EVENT_ACTION_STOP EV1 Counter stop on event TCC_EVENT_ACTION_COUNT_EVENT Counter count on event EV1 TCC_EVENT_ACTION_INCREMENT Counter increment on event EV1 TCC_EVENT_ACTION_COUNT_DURING_ACTIVE Counter count during active state of asynchronous event EV1 21.2.2.4 Timer/Counter Reloading The TCC also has a configurable reload action, used when a re-trigger event occurs. Examples of a re-trigger event could be the counter reaching the maximum value when counting up, or when an event from the event system makes the counter to re-trigger. The reload action determines if the prescaler should be reset, and on which clock. The counter will always be reloaded with the value it is set to start counting. The user can choose between three different reload actions, described in Table 21-3: TCC Module Reload Actions on page 443. Table 21-3. TCC Module Reload Actions Reload action Description TCC_RELOAD_ACTION_GCLK Reload TCC counter value on next GCLK cycle. Leave prescaler as-is. TCC_RELOAD_ACTION_PRESC Reloads TCC counter value on next prescaler clock. Leave prescaler as-is. TCC_RELOAD_ACTION_RESYNC Reload TCC counter value on next GCLK cycle. Clear prescaler to zero. The reload action to use will depend on the specific application being implemented. One example is when an external trigger for a reload occurs; if the TCC uses the prescaler, the counter in the prescaler should not have a value between zero and the division factor. The counter in the TCC module and the counter in the prescaler should both start at zero. If the counter is set to re-trigger when it reaches the maximum value, this is not the right option to use. In such a case it would be better if the prescaler is left unaltered when the re-trigger happens, letting the counter reset on the next GCLK cycle. 21.2.2.5 One-shot Mode The TCC module can be configured in one-shot mode. When configured in this manner, starting the timer will cause it to count until the next overflow or underflow condition before automatically halting, waiting to be manually triggered by the user application software or an event from the event system. 21.2.3 Capture Operations In capture operations, any event from the event system or a pin change can trigger a capture of the counter value. This captured counter value can be used as timestamps for the events, or it can be used in frequency and pulse width capture. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 443 21.2.3.1 Capture Operations - Event Event capture is a simple use of the capture functionality, designed to create timestamps for specific events. When the input event appears, the current counter value is copied into the corresponding compare/capture register, which can then be read by the user application. Note that when performing any capture operation, there is a risk that the counter reaches its top value (MAX) when counting up, or the bottom value (zero) when counting down, before the capture event occurs. This can distort the result, making event timestamps to appear shorter than they really are. In this case, the user application should check for timer overflow when reading a capture result in order to detect this situation and perform an appropriate adjustment. Before checking for a new capture, TCC_STATUS_COUNT_OVERFLOW should be checked. The response to an overflow error is left to the user application, however it may be necessary to clear both the overflow flag and the capture flag upon each capture reading. 21.2.3.2 Capture Operations - Pulse Width Pulse Width Capture mode makes it possible to measure the pulse width and period of PWM signals. This mode uses two capture channels of the counter. There are two modes for pulse width capture; Pulse Width Period (PWP) and Period Pulse Width (PPW). In PWP mode, capture channel 0 is used for storing the pulse width and capture channel 1 stores the observed period. While in PPW mode, the roles of the two capture channels are reversed. As in the above example it is necessary to poll on interrupt flags to see if a new capture has happened and check that a capture overflow error has not occurred. Refer to Timer/Counter Control Inputs (Events) to set up the input event to perform pulse width capture. 21.2.4 Compare Match Operation In compare match operation, Compare/Capture registers are compared with the counter value. When the timer's count value matches the value of a compare channel, a user defined action can be taken. 21.2.4.1 Basic Timer A Basic Timer is a simple application where compare match operation is used to determine when a specific period has elapsed. In Basic Timer operations, one or more values in the module's Compare/Capture registers are used to specify the time (in terms of the number of prescaled GCLK cycles, or input events) at which an action should be taken by the microcontroller. This can be an Interrupt Service Routine (ISR), event generation via the event system, or a software flag that is polled from the user application. 21.2.4.2 Waveform Generation Waveform generation enables the TCC module to generate square waves, or if combined with an external passive low-pass filter, analog waveforms. 21.2.4.3 Waveform Generation - PWM Pulse width modulation is a form of waveform generation and a signalling technique that can be useful in many applications. When PWM mode is used, a digital pulse train with a configurable frequency and duty cycle can be generated by the TCC module and output to a GPIO pin of the device. Often PWM is used to communicate a control or information parameter to an external circuit or component. Differing impedances of the source generator and sink receiver circuits is less of an issue when using PWM compared to using an analog voltage value, as noise will not generally affect the signal's integrity to a meaningful extent. Figure 21-2: Example Of PWM In Single-Slope Mode, and Different Counter Operations on page 445 illustrates operations and different states of the counter and its output when using the timer in Normal PWM mode (Single Slope). As can be seen, the TOP/PERIOD value is unchanged and is set to MAX. The compare match value is changed at several points to illustrate the resulting waveform output changes. The PWM output is set to normal (i.e. non-inverted) output mode. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 444 Figure 21-2. Example Of PWM In Single-Slope Mode, and Different Counter Operations TOP/Period = Max (PER) (COUNT) Com pare/Mat ch value (CCx) (CCx) Several PWM modes are supported by the TCC module, refer to datasheet for the details on PWM waveform generation. 21.2.4.4 Waveform Generation - Frequency Normal Frequency Generation is in many ways identical to PWM generation. However, only in Frequency Generation, a toggle occurs on the output when a match on a compare channels occurs. When the Match Frequency Generation is used, the timer value is reset on match condition, resulting in a variable frequency square wave with a fixed 50% duty cycle. 21.2.5 Waveform Extended Controls 21.2.5.1 Pattern Generation Pattern insertion allows the TCC module to change the actual pin output level without modifying the compare/match settings. Table 21-4. TCC Module Output Pattern Generation Pattern Description TCC_OUTPUT_PATTERN_DISABLE Pattern disabled, generate output as is TCC_OUTPUT_PATTERN_0 Generate pattern 0 on output (keep the output LOW) TCC_OUTPUT_PATTERN_1 Generate pattern 1 on output (keep the output HIGH) 21.2.5.2 Recoverable Faults The recoverable faults can trigger one or several of following fault actions: 1. *Halt* action: The recoverable faults can halt the TCC timer/counter, so that the final output wave is kept at a defined state. When the fault state is removed it is possible to recover the counter and waveform generation. The halt action is defined as: Table 21-5. TCC Module Recoverable Fault Halt Actions Action Description TCC_FAULT_HALT_ACTION_DISABLE Halt action is disabled AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 445 Action Description TCC_FAULT_HALT_ACTION_HW_HALT The timer/counter is halted as long as the corresponding fault is present TCC_FAULT_HALT_ACTION_SW_HALT The timer/counter is halted until the corresponding fault is removed and fault state cleared by software TCC_FAULT_HALT_ACTION_NON_RECOVERABLE Force all the TCC output pins to a pre-defined level, as what Non-Recoverable Fault do 2. *Restart* action: When enabled, the recoverable faults can restart the TCC timer/counter. 3. *Keep* action: When enabled, the recoverable faults can keep the corresponding channel output to zero when the fault condition is present. 4. *Capture* action: When the recoverable fault occurs, the capture action can time stamps the corresponding fault. The following capture mode is supported: Table 21-6. TCC Module Recoverable Fault Capture Actions Action Description TCC_FAULT_CAPTURE_DISABLE Capture action is disabled TCC_FAULT_CAPTURE_EACH Equivalent to standard capture operation, on each fault occurrence the time stamp is captured TCC_FAULT_CAPTURE_MINIMUM Get the minimum time stamped value in all time stamps TCC_FAULT_CAPTURE_MAXIMUM Get the maximum time stamped value in all time stamps TCC_FAULT_CAPTURE_SMALLER Time stamp the fault input if the value is smaller than last one TCC_FAULT_CAPTURE_BIGGER Time stamp the fault input if the value is bigger than last one TCC_FAULT_CAPTURE_CHANGE Time stamp the fault input if the time stamps changes its increment direction In TCC module, only the first two compare channels (CC0 and CC1) can work with recoverable fault inputs. The corresponding event inputs (TCCx MC0 and TCCx MC1) are then used as fault inputs respectively. The faults are called Fault A and Fault B. The recoverable fault can be filtered or effected by corresponding channel output. On fault condition there are many other settings that can be chosen. Refer to data sheet for more details about the recoverable fault operations. 21.2.5.3 Non-Recoverable Faults The non-recoverable faults force all the TCC output pins to a pre-defined level (can be forced to 0 or 1). The input control signal of non-recoverable fault is from timer/counter event (TCCx EV0 and TCCx EV1). To enable non-recoverable fault, corresponding TCEx event action must be set to non-recoverable fault action (TCC_EVENT_ACTION_NON_RECOVERABLE_FAULT on page 474). Refer to Timer/Counter Control Inputs (Events) to see the available event input action. 21.2.6 Double and Circular Buffering The pattern, period and the compare channels registers are double buffered. For these options there are effective registers (PATT, PER, and CCx) and buffer registers (PATTB, PERB, and CCx). When writing to the buffer registers, the values are buffered and will be committed to effective registers on UPDATE condition. Usually the buffered value is cleared after it's committed, but there is also option to circular the register buffers. The period (PER) and four lowest compare channels register (CCx, x is 0 ~ 3) support this function. When circular buffer is used, on UPDATE the previous period or compare values are copied back into the corresponding period AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 446 buffer and compare buffers. This way, the register value and its buffer register value is actually switched on UPDATE condition, and will be switched back on next UPDATE condition. For input capture, the buffer register (CCBx) and the corresponding capture channel register (CCx) act like a FIFO. When regular register (CCx) is empty or read, any content in the buffer register is passed to regular one. In TCC module driver, when the double buffering write is enabled, any write through tcc_set_top_value(), tcc_set_compare_value(), and tcc_set_pattern() will be done to the corresponding buffer register. Then the value in the buffer register will be transferred to the regular register on the next UPDATE condition or by a force UPDATE using tcc_force_double_buffer_update(). 21.2.7 Sleep Mode TCC modules can be configured to operate in any sleep mode, with its "run in standby" function enabled. It can wake up the device using interrupts or perform internal actions with the help of the Event System. 21.3 Special Considerations 21.3.1 Module Features The features of TCC, such as timer/counter size, number of compare capture channels, and number of outputs, are dependent on the TCC module instance being used. 21.3.1.1 SAM TCC Feature List For SAM D21/R21/L21, the TCC features are: Table 21-7. TCC module features for SAM D21/R21/L21 TCC# Match/ Wave Capture outputs channels Counter size [bits] Fault Dithering Output matrix DeadSWAP Time insertion Pattern 0 4 8 24 Y Y Y Y 1 2 4 24 Y Y 2 2 2 16 Y Y Y Y 21.3.1.2 SAM D10/D11 TCC Feature List For SAM D10/D11, the TCC features are: Table 21-8. TCC Module Features For SAM D10/D11 21.3.2 TCC# Match/ Wave Capture outputs channels Counter size [bits] Fault Dithering Output matrix DeadSWAP Time insertion Pattern 0 4 24 Y Y Y Y 8 Y Y Channels vs. Pin outs As the TCC module may have more waveform output pins than the number of compare/capture channels, the free pins (with number higher than number of channels) will reuse the waveform generated by channels subsequently. E.g., if the number of channels is four and the number of wave output pins is eight, channel 0 output will be available on out pin 0 and 4, channel 1 output on wave out pin 1 and 5, and so on. 21.4 Extra Information For extra information, see Extra Information for TCC Driver. This includes: ● Acronyms ● Dependencies AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 447 21.5 ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for TCC Driver. 21.6 API Overview 21.6.1 Variable and Type Definitions 21.6.1.1 Type tcc_callback_t typedef void(* tcc_callback_t )(struct tcc_module *const module) Type definition for the TCC callback function. 21.6.2 Structure Definitions 21.6.2.1 Struct tcc_capture_config Structure used when configuring TCC channels in capture mode. Table 21-9. Members Type Name Description enum tcc_channel_function channel_function[] Channel functions selection (capture/match). 21.6.2.2 Struct tcc_config Configuration struct for a TCC instance. This structure should be initialized by the tcc_get_config_defaults function before being modified by the user application. Table 21-10. Members Type Name Description union tcc_config.@5 @5 TCC match/capture configurations. struct tcc_counter_config counter Structure for configuring TCC base timer/counter. bool double_buffering_enabled Set to true to enable double buffering write. When enabled any write through tcc_set_top_value(), tcc_set_compare_value() and tcc_set_pattern() will direct to the buffer register as buffered value, and the buffered value will be committed to effective register on UPDATE condition, if update is not 1 locked. struct tcc_pins_config pins Structure for configuring TCC output pins. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 448 Type Name Description bool run_in_standby When true the module is enabled during standby. struct tcc_wave_extension_config wave_ext Structure for configuring TCC waveform extension. Notes: 1 The init values in tcc_config for tcc_init are always filled to effective registers, no matter double buffering enabled or not. 21.6.2.3 Union tcc_config.__unnamed__ TCC match/capture configurations. Table 21-11. Members Type Name Description struct tcc_capture_config capture Helps to configure a TCC channel in capture mode. struct tcc_match_wave_config compare For configuring a TCC channel in compare mode. struct tcc_match_wave_config wave Serves the same purpose as compare. Used as an alias for compare, when a TCC channel is configured for wave generation. 21.6.2.4 Struct tcc_counter_config Structure for configuring a TCC as a counter. Table 21-12. Members Type Name Description enum tcc_clock_prescaler clock_prescaler Specifies the prescaler value for GCLK_TCC. enum gclk_generator clock_source GCLK generator used to clock the peripheral. uint32_t count Value to initialize the count register. enum tcc_count_direction direction Specifies the direction for the TCC to count. bool oneshot When true, counter will be stopped on the next hardware or software re-trigger event or overflow/ underflow. uint32_t period Period/top and period/top buffer values for counter. enum tcc_reload_action reload_action Specifies the reload or reset time of the counter and prescaler resynchronization on a re-trigger event for the TCC. 21.6.2.5 Struct tcc_events Event flags for the tcc_enable_events() and tcc_disable_events(). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 449 Table 21-13. Members Type Name Description bool generate_event_on_channel[] Generate an output event on a channel capture/match. Specify which channels will generate events. bool generate_event_on_counter_event Generate an output event on counter boundary. See tcc_event_output_action. bool generate_event_on_counter_overflow Generate an output event on counter overflow/underflow. bool generate_event_on_counter_retrigger Generate an output event on counter retrigger. struct tcc_input_event_config input_config[] Input events configuration. bool on_event_perform_channel_action[] Perform the configured event action when an incoming channel event is signalled. bool on_input_event_perform_action[] Perform the configured event action when an incoming event is signalled. struct tcc_output_event_config output_config Output event configuration. Type Name Description enum tcc_event_action action Event action on incoming event. bool invert Invert incoming event input line. bool modify_action Modify event action. 21.6.2.6 Struct tcc_input_event_config For configuring an input event. Table 21-14. Members 21.6.2.7 Struct tcc_match_wave_config The structure, which helps to configure a TCC channel for compare operation and wave generation. Table 21-15. Members Type Name Description enum tcc_channel_function channel_function[] Channel functions selection (capture/match). uint32_t match[] Value to be used for compare match on each channel. enum tcc_wave_generation wave_generation Specifies which waveform generation mode to use. enum tcc_wave_polarity wave_polarity[] Specifies polarity for match output waveform generation. enum tcc_ramp wave_ramp Specifies Ramp mode for waveform generation. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 450 21.6.2.8 Struct tcc_module TCC software instance structure, used to retain software state information of an associated hardware module instance. Note The fields of this structure should not be altered by the user application; they are reserved only for module-internal use. Table 21-16. Members Type Name Description tcc_callback_t callback[] Array of callbacks. bool double_buffering_enabled Set to true to write to buffered registers. uint32_t enable_callback_mask Bit mask for callbacks enabled. Tcc * hw Hardware module pointer of the associated Timer/Counter peripheral. uint32_t register_callback_mask Bit mask for callbacks registered. 21.6.2.9 Struct tcc_non_recoverable_fault_config Table 21-17. Members Type Name Description uint8_t filter_value Fault filter value applied on TCEx event input line (0x0 ~ 0xF). Must be 0 when TCEx event is used as synchronous event. enum tcc_fault_state_output output Output. 21.6.2.10 Struct tcc_output_event_config Structure used for configuring an output event. Table 21-18. Members Type Name Description enum tcc_event_generation_selection generation_selection It decides which part of the counter cycle the counter event output is generated. bool modify_generation_selection A switch to allow enable/disable of events, without modifying the event output configuration. 21.6.2.11 Struct tcc_pins_config Structure which is used when taking wave output from TCC. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 451 Table 21-19. Members Type Name Description bool enable_wave_out_pin[] When true, PWM output pin for the given channel is enabled. uint32_t wave_out_pin[] Specifies pin output for each channel. uint32_t wave_out_pin_mux[] Specifies MUX setting for each output channel pin. Type Name Description enum tcc_fault_blanking blanking Fault Blanking Start Point for recoverable Fault. uint8_t blanking_cycles Fault blanking value (0 ~ 255), disable input source for several TCC clocks after the detection of the waveform edge. enum tcc_fault_capture_action capture_action Capture action for recoverable Fault. enum tcc_fault_capture_channel capture_channel Channel triggered by recoverable Fault. uint8_t filter_value Fault filter value applied on MCEx event input line (0x0 ~ 0xF). Must be 0 when MCEx event is used as synchronous event. Apply to both recoverable and non-recoverable fault. enum tcc_fault_halt_action halt_action Halt action for recoverable Fault. bool keep Set to true to enable keep action (keep until end of TCC cycle). bool qualification Set to true to enable input qualification (disable input when output is inactive). bool restart Set to true to enable restart action. enum tcc_fault_source source Specifies if the event input generates recoverable Fault. The event system channel connected to MCEx event input must be configured as asynchronous. 21.6.2.12 Struct tcc_recoverable_fault_config Table 21-20. Members 21.6.2.13 Struct tcc_wave_extension_config This structure is used to specify the waveform extension features for TCC. Table 21-21. Members Type Name Description bool invert[] Invert waveform final outputs lines. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 452 21.6.3 Type Name Description struct tcc_non_recoverable_fault_config non_recoverable_fault[] Configuration for non-recoverable faults. struct tcc_recoverable_fault_config recoverable_fault[] Configuration for recoverable faults. Macro Definitions 21.6.3.1 Module Status Flags TCC status flags, returned by tcc_get_status() and cleared by tcc_clear_status(). Macro TCC_STATUS_CHANNEL_MATCH_CAPTURE #define TCC_STATUS_CHANNEL_MATCH_CAPTURE(ch) \ (1UL << (ch)) Timer channel ch (0 ~ 3) has matched against its compare value, or has captured a new value. Macro TCC_STATUS_CHANNEL_OUTPUT #define TCC_STATUS_CHANNEL_OUTPUT(ch) \ (1UL << ((ch)+8)) Timer channel ch (0 ~ 3) match/compare output state. Macro TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR #define TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR(x) \ (1UL << ((x)+16)) A Non-Recoverable Fault x (0 ~ 1) has occurred. Macro TCC_STATUS_RECOVERABLE_FAULT_OCCUR #define TCC_STATUS_RECOVERABLE_FAULT_OCCUR(n) \ (1UL << ((n)+18)) A Recoverable Fault n (0 ~ 1 representing A ~ B) has occured. Macro TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT #define TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT(x) \ (1UL << ((x)+20)) The Non-Recoverable Fault x (0 ~ 1) input is present. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 453 Macro TCC_STATUS_RECOVERABLE_FAULT_PRESENT #define TCC_STATUS_RECOVERABLE_FAULT_PRESENT(n) \ (1UL << ((n)+22)) A Recoverable Fault n (0 ~ 1 representing A ~ B) is present. Macro TCC_STATUS_SYNC_READY #define TCC_STATUS_SYNC_READY (1UL << 23) Timer registers synchronization has completed, and the synchronized count value may be read. Macro TCC_STATUS_CAPTURE_OVERFLOW #define TCC_STATUS_CAPTURE_OVERFLOW (1UL << 24) A new value was captured before the previous value was read, resulting in lost data. Macro TCC_STATUS_COUNTER_EVENT #define TCC_STATUS_COUNTER_EVENT (1UL << 25) A counter event occurred. Macro TCC_STATUS_COUNTER_RETRIGGERED #define TCC_STATUS_COUNTER_RETRIGGERED (1UL << 26) A counter retrigger occurred. Macro TCC_STATUS_COUNT_OVERFLOW #define TCC_STATUS_COUNT_OVERFLOW (1UL << 27) The timer count value has overflowed from its maximum value to its minimum when counting upward, or from its minimum value to its maximum when counting downward. Macro TCC_STATUS_RAMP_CYCLE_INDEX #define TCC_STATUS_RAMP_CYCLE_INDEX (1UL << 28) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 454 Ramp period cycle index. In ramp operation, each two period cycles are marked as cycle A and B, the index 0 represents cycle A and 1 represents cycle B. Macro TCC_STATUS_STOPPED #define TCC_STATUS_STOPPED (1UL << 29) The counter has been stopped (due to disable, stop command or one-shot). 21.6.3.2 Macro _TCC_CHANNEL_ENUM_LIST #define _TCC_CHANNEL_ENUM_LIST(type) \ MREPEAT(TCC_NUM_CHANNELS, _TCC_ENUM, type##_CHANNEL) 21.6.3.3 Macro _TCC_ENUM #define _TCC_ENUM(n, type) \ TCC_##type##_##n, 21.6.3.4 Macro _TCC_WO_ENUM_LIST #define _TCC_WO_ENUM_LIST(type) \ MREPEAT(TCC_NUM_WAVE_OUTPUTS, _TCC_ENUM, type) 21.6.3.5 Macro TCC_NUM_CHANNELS #define TCC_NUM_CHANNELS 4 Maximum number of channels supported by the driver (Channel index from 0 to TCC_NUM_CHANNELS - 1). 21.6.3.6 Macro TCC_NUM_FAULTS #define TCC_NUM_FAULTS 2 Maximum number of (recoverable) faults supported by the driver. 21.6.3.7 Macro TCC_NUM_WAVE_OUTPUTS #define TCC_NUM_WAVE_OUTPUTS 8 Maximum number of wave outputs lines supported by the driver (Output line index from 0 to TCC_NUM_WAVE_OUTPUTS - 1). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 455 21.6.4 Function Definitions 21.6.4.1 Driver Initialization and Configuration Function tcc_is_syncing() Determines if the hardware module is currently synchronizing to the bus. bool tcc_is_syncing( const struct tcc_module *const module_inst) Checks to see if the underlying hardware peripheral module is currently synchronizing across multiple clock domains to the hardware bus. This function can be used to delay further operations on a module until such time that it is ready, to prevent blocking delays for synchronization in the user application. Table 21-22. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Returns Synchronization status of the underlying hardware module. Table 21-23. Return Values Return value Description false If the module has completed synchronization true If the module synchronization is ongoing Function tcc_get_config_defaults() Initializes config with predefined default values. void tcc_get_config_defaults( struct tcc_config *const config, Tcc *const hw) This function will initialize a given TCC configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. The default configuration is as follows: ● Don't run in standby ● When setting top,compare or pattern by API, do double buffering write ● The base timer/counter configurations: ● GCLK generator 0 clock source ● No prescaler ● GCLK reload action AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 456 ● ● ● Count upward ● Don't perform one-shot operations ● Counter starts on 0 ● Period/top value set to maximum The match/capture configurations: ● All Capture compare channel value set to 0 ● No capture enabled (all channels use compare function) ● Normal frequency wave generation ● Waveform generation polarity set to 0 ● Don't perform ramp on waveform The waveform extension configurations: ● No recoverable fault is enabled, fault actions are disabled, filter is set to 0 ● No non-recoverable fault state output is enabled and filter is 0 ● No inversion of waveform output ● No channel output enabled ● No PWM pin output enabled ● Pin and MUX configuration not set Table 21-24. Parameters Data direction Parameter name Description [out] config Pointer to a TCC module configuration structure to set [in] hw Pointer to the TCC hardware module Function tcc_init() Initializes a hardware TCC module instance. enum status_code tcc_init( struct tcc_module *const module_inst, Tcc *const hw, const struct tcc_config *const config) Enables the clock and initializes the given TCC module, based on the given configuration values. Table 21-25. Parameters Data direction Parameter name Description [in, out] module_inst Pointer to the software module instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 457 Data direction Parameter name Description [in] hw Pointer to the TCC hardware module [in] config Pointer to the TCC configuration options struct Returns Status of the initialization procedure. Table 21-26. Return Values Return value Description STATUS_OK The module was initialized successfully STATUS_BUSY Hardware module was busy when the initialization procedure was attempted STATUS_INVALID_ARG An invalid configuration option or argument was supplied STATUS_ERR_DENIED Hardware module was already enabled 21.6.4.2 Event Management Function tcc_enable_events() Enables the TCC module event input or output. enum status_code tcc_enable_events( struct tcc_module *const module_inst, struct tcc_events *const events) Enables one or more input or output events to or from the TCC module. See tcc_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 21-27. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] events Struct containing flags of events to enable or configure Status of the events setup procedure. Table 21-28. Return Values Return value Description STATUS_OK The module was initialized successfully STATUS_INVALID_ARG An invalid configuration option or argument was supplied AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 458 Function tcc_disable_events() Disables the event input or output of a TCC instance. void tcc_disable_events( struct tcc_module *const module_inst, struct tcc_events *const events) Disables one or more input or output events for the given TCC module. See tcc_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 21-29. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] events Struct containing flags of events to disable 21.6.4.3 Enable/Disable/Reset Function tcc_enable() Enable the TCC module. void tcc_enable( const struct tcc_module *const module_inst) Enables a TCC module that has been previously initialized. The counter will start when the counter is enabled. Note When the counter is configured to re-trigger on an event, the counter will not start until the next incoming event appears. Then it restarts on any following event. Table 21-30. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Function tcc_disable() Disables the TCC module. void tcc_disable( const struct tcc_module *const module_inst) Disables a TCC module and stops the counter. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 459 Table 21-31. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Function tcc_reset() Resets the TCC module. void tcc_reset( const struct tcc_module *const module_inst) Resets the TCC module, restoring all hardware module registers to their default values and disabling the module. The TCC module will not be accessible while the reset is being performed. Note When resetting a 32-bit counter only the master TCC module's instance structure should be passed to the function. Table 21-32. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 21.6.4.4 Set/Toggle Count Direction Function tcc_set_count_direction() Sets the TCC module count direction. void tcc_set_count_direction( const struct tcc_module *const module_inst, enum tcc_count_direction dir) Sets the count direction of an initialized TCC module. The specified TCC module can remain running or stopped. Table 21-33. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] dir New timer count direction to set Function tcc_toggle_count_direction() Toggles the TCC module count direction. void tcc_toggle_count_direction( const struct tcc_module *const module_inst) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 460 Toggles the count direction of an initialized TCC module. The specified TCC module can remain running or stopped. Table 21-34. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 21.6.4.5 Get/Set Count Value Function tcc_get_count_value() Get count value of the given TCC module. uint32_t tcc_get_count_value( const struct tcc_module *const module_inst) Retrieves the current count value of a TCC module. The specified TCC module can remain running or stopped. Table 21-35. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Returns Count value of the specified TCC module. Function tcc_set_count_value() Sets count value for the given TCC module. enum status_code tcc_set_count_value( const struct tcc_module *const module_inst, const uint32_t count) Sets the timer count value of an initialized TCC module. The specified TCC module can remain running or stopped. Table 21-36. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] count New timer count value to set Status which indicates whether the new value is set. Table 21-37. Return Values Return value Description STATUS_OK The timer count was updated successfully STATUS_ERR_INVALID_ARG An invalid timer counter size was specified AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 461 21.6.4.6 Stop/Restart Counter Function tcc_stop_counter() Stops the counter. void tcc_stop_counter( const struct tcc_module *const module_inst) This function will stop the counter. When the counter is stopped the value in the count register is set to 0 if the counter was counting up, or maximum or the top value if the counter was counting down. Table 21-38. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Function tcc_restart_counter() Starts the counter from beginning. void tcc_restart_counter( const struct tcc_module *const module_inst) Restarts an initialized TCC module's counter. Table 21-39. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 21.6.4.7 Get/Set Compare/Capture Register Function tcc_get_capture_value() Gets the TCC module capture value. uint32_t tcc_get_capture_value( const struct tcc_module *const module_inst, const enum tcc_match_capture_channel channel_index) Retrieves the capture value in the indicated TCC module capture channel. Table 21-40. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] channel_index Index of the Compare Capture channel to read AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 462 Returns Capture value stored in the specified timer channel. Function tcc_set_compare_value() Sets a TCC module compare value. enum status_code tcc_set_compare_value( const struct tcc_module *const module_inst, const enum tcc_match_capture_channel channel_index, const uint32_t compare) Writes a compare value to the given TCC module compare/capture channel. If double buffering is enabled it always write to the buffer register. The value will then be updated immediately by calling tcc_force_double_buffer_update(), or be updated when the lock update bit is cleared and the UPDATE condition happen. Table 21-41. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] channel_index Index of the compare channel to write to [in] compare New compare value to set Status of the compare update procedure. Table 21-42. Return Values Return value Description STATUS_OK The compare value was updated successfully STATUS_ERR_INVALID_ARG An invalid channel index was supplied or compare value exceed resolution 21.6.4.8 Set Top Value Function tcc_set_top_value() Set the timer TOP/PERIOD value. enum status_code tcc_set_top_value( const struct tcc_module *const module_inst, const uint32_t top_value) This function writes the given value to the PER/PERB register. If double buffering is enabled it always write to the buffer register (PERB). The value will then be updated immediately by calling tcc_force_double_buffer_update(), or be updated when the lock update bit is cleared and the UPDATE condition happen. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 463 When using MFRQ, the top value is defined by the CC0 register value and the PER value is ignored, so tcc_set_compare_value (module,channel_0,value) must be used instead of this function to change the actual top value in that case. For all other waveforms operation the top value is defined by PER register value. Table 21-43. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] top_value New value to be loaded into the PER/PERB register Returns Status of the TOP set procedure. Table 21-44. Return Values Return value Description STATUS_OK The timer TOP value was updated successfully STATUS_ERR_INVALID_ARG An invalid channel index was supplied or top/period value exceed resolution 21.6.4.9 Set Output Pattern Function tcc_set_pattern() Sets the TCC module waveform output pattern. enum status_code tcc_set_pattern( const struct tcc_module *const module_inst, const uint32_t line_index, const enum tcc_output_pattern pattern) Force waveform output line to generate specific pattern (0, 1, or as is). If double buffering is enabled it always write to the buffer register. The value will then be updated immediately by calling tcc_force_double_buffer_update(), or be updated when the lock update bit is cleared and the UPDATE condition happen. Table 21-45. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] line_index Output line index [in] pattern Output pattern to use (tcc_output_pattern) Status of the pattern set procedure. Table 21-46. Return Values Return value Description STATUS_OK The PATT register is updated successfully AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 464 Return value Description STATUS_ERR_INVALID_ARG An invalid line index was supplied 21.6.4.10 Set Ramp Index Function tcc_set_ramp_index() Sets the TCC module ramp index on next cycle. void tcc_set_ramp_index( const struct tcc_module *const module_inst, const enum tcc_ramp_index ramp_index) In RAMP2 and RAMP2A operation, we can force either cycle A or cycle B at the output, on the next clock cycle. When ramp index command is disabled, cycle A and cycle B will appear at the output, on alternate clock cycles. See tcc_ramp. Table 21-47. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] ramp_index Ramp index (tcc_ramp_index) of the next cycle 21.6.4.11 Status Management Function tcc_is_running() Checks if the timer/counter is running. bool tcc_is_running( struct tcc_module *const module_inst) Table 21-48. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Returns Status which indicates whether the module is running. Table 21-49. Return Values Return value Description true The timer/counter is running false The timer/counter is stopped Function tcc_get_status() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 465 Retrieves the current module status. uint32_t tcc_get_status( struct tcc_module *const module_inst) Retrieves the status of the module, giving overall state information. Table 21-50. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Returns Bitmask of TCC_STATUS_* flags. Table 21-51. Return Values Return value Description TCC_STATUS_CHANNEL_MATCH_CAPTURE(n) Channel n match/capture has occured TCC_STATUS_CHANNEL_OUTPUT(n) Channel n match/capture output state TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR(x) Non-recoverable fault x has occured TCC_STATUS_RECOVERABLE_FAULT_OCCUR(n) Recoverable fault n has occured TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT(x) Non-recoverable fault x input present TCC_STATUS_RECOVERABLE_FAULT_PRESENT(n) Recoverable fault n input present TCC_STATUS_SYNC_READY None of register is syncing TCC_STATUS_CAPTURE_OVERFLOW Timer capture data has overflowed TCC_STATUS_COUNTER_EVENT Timer counter event has occurred TCC_STATUS_COUNT_OVERFLOW Timer count value has overflowed TCC_STATUS_COUNTER_RETRIGGERED Timer counter has been retriggered TCC_STATUS_STOP Timer counter has been stopped TCC_STATUS_RAMP_CYCLE_INDEX Wave ramp index for cycle Function tcc_clear_status() Clears a module status flag. void tcc_clear_status( struct tcc_module *const module_inst, const uint32_t status_flags) Clears the given status flag of the module. Table 21-52. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct [in] status_flags Bitmask of TCC_STATUS_* flags to clear AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 466 21.6.4.12 Double Buffering Management Function tcc_enable_double_buffering() Enable TCC double buffering write. void tcc_enable_double_buffering( struct tcc_module *const module_inst) When double buffering write is enabled, following function will write values to buffered registers instead of effective ones (buffered): ● PERB: through tcc_set_top_value() ● CCBx(x is 0~3): through tcc_set_compare_value() ● PATTB: through tcc_set_pattern() Then on UPDATE condition the buffered registers are committed to regular ones to take effect. Table 21-53. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_disable_double_buffering() Disable TCC double buffering Write. void tcc_disable_double_buffering( struct tcc_module *const module_inst) When double buffering write is disabled, following function will write values to effective registers (not buffered): ● PER: through tcc_set_top_value() ● CCx(x is 0~3): through tcc_set_compare_value() ● PATT: through tcc_set_pattern() Note This function does not lock double buffer update, which means on next UPDATE condition the last written buffered values will be committed to take effect. Invoke tcc_lock_double_buffer_update() before this function to disable double buffering update, if this change is not expected. Table 21-54. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_lock_double_buffer_update() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 467 Lock the TCC double buffered registers updates. void tcc_lock_double_buffer_update( struct tcc_module *const module_inst) Locks the double buffered registers so they will not be updated through their buffered values on UPDATE conditions. Table 21-55. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_unlock_double_buffer_update() Unlock the TCC double buffered registers updates. void tcc_unlock_double_buffer_update( struct tcc_module *const module_inst) Unlock the double buffered registers so they will be updated through their buffered values on UPDATE conditions. Table 21-56. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_force_double_buffer_update() Force the TCC double buffered registers to update once. void tcc_force_double_buffer_update( struct tcc_module *const module_inst) Table 21-57. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_enable_circular_buffer_top() Enable Circular option for double buffered Top/Period Values. void tcc_enable_circular_buffer_top( struct tcc_module *const module_inst) Enable circular option for the double buffered top/period values. On each UPDATE condition, the contents of PERB and PER are switched, meaning that the contents of PERB are transferred to PER and the contents of PER are transferred to PERB. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 468 Table 21-58. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_disable_circular_buffer_top() Disable Circular option for double buffered Top/Period Values. void tcc_disable_circular_buffer_top( struct tcc_module *const module_inst) Stop circularing the double buffered top/period values. Table 21-59. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct Function tcc_set_double_buffer_top_values() Set the timer TOP/PERIOD value and buffer value. enum status_code tcc_set_double_buffer_top_values( const struct tcc_module *const module_inst, const uint32_t top_value, const uint32_t top_buffer_value) This function writes the given value to the PER and PERB register. Usually as preparation for double buffer or circulared double buffer (circular buffer). When using MFRQ, the top values are defined by the CC0 and CCB0, the PER and PERB values are ignored, so tcc_set_double_buffer_compare_values (module,channel_0,value,buffer) must be used instead of this function to change the actual top values in that case. For all other waveforms operation the top values are defined by PER and PERB registers values. Table 21-60. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] top_value New value to be loaded into the PER register [in] top_buffer_value New value to be loaded into the PERB register Status of the TOP set procedure. Table 21-61. Return Values Return value Description STATUS_OK The timer TOP value was updated successfully AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 469 Return value Description STATUS_ERR_INVALID_ARG An invalid channel index was supplied or top/period value exceed resolution Function tcc_enable_circular_buffer_compare() Enable circular option for double buffered compare values. enum status_code tcc_enable_circular_buffer_compare( struct tcc_module *const module_inst, enum tcc_match_capture_channel channel_index) Enable circular option for the double buffered channel compare values. On each UPDATE condition, the contents of CCBx and CCx are switched, meaning that the contents of CCBx are transferred to CCx and the contents of CCx are transferred to CCBx. Table 21-62. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct [in] channel_index Index of the compare channel to set up to Table 21-63. Return Values Return value Description STATUS_OK The module was initialized successfully STATUS_INVALID_ARG An invalid channel index is supplied Function tcc_disable_circular_buffer_compare() Disable circular option for double buffered compare values. enum status_code tcc_disable_circular_buffer_compare( struct tcc_module *const module_inst, enum tcc_match_capture_channel channel_index) Stop circularing the double buffered compare values. Table 21-64. Parameters Data direction Parameter name Description [in] module_inst Pointer to the TCC software instance struct [in] channel_index Index of the compare channel to set up to Table 21-65. Return Values Return value Description STATUS_OK The module was initialized successfully AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 470 Return value Description STATUS_INVALID_ARG An invalid channel index is supplied Function tcc_set_double_buffer_compare_values() Sets a TCC module compare value and buffer value. enum status_code tcc_set_double_buffer_compare_values( struct tcc_module *const module_inst, enum tcc_match_capture_channel channel_index, const uint32_t compare, const uint32_t compare_buffer) Writes compare value and buffer to the given TCC module compare/capture channel. Usually as preparation for double buffer or circulared double buffer (circular buffer). Table 21-66. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] channel_index Index of the compare channel to write to [in] compare New compare value to set [in] compare_buffer New compare buffer value to set Status of the compare update procedure. Table 21-67. Return Values 21.6.5 Return value Description STATUS_OK The compare value was updated successfully STATUS_ERR_INVALID_ARG An invalid channel index was supplied or compare value exceed resolution Enumeration Definitions 21.6.5.1 Enum tcc_callback Enum for the possible callback types for the TCC module. Table 21-68. Members Enum value Description TCC_CALLBACK_OVERFLOW Callback for TCC overflow. TCC_CALLBACK_RETRIGGER Callback for TCC Retrigger. TCC_CALLBACK_COUNTER_EVENT Callback for TCC counter event. TCC_CALLBACK_ERROR Callback for capture overflow error. TCC_CALLBACK_FAULTA Callback for Recoverable Fault A. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 471 Enum value Description TCC_CALLBACK_FAULTB Callback for Recoverable Fault B. TCC_CALLBACK_FAULT0 Callback for Non-Recoverable Fault 0. TCC_CALLBACK_FAULT1 Callback for Non-Recoverable Fault 1. TCC_CALLBACK_CHANNEL_n Channel callback type table for TCC Each TCC module may contain several callback types for channels; each channel will have its own callback type in the table, with the channel index number substituted for "n" in the channel callback type (e.g. TCC_MATCH_CAPTURE_CHANNEL_0). 21.6.5.2 Enum tcc_channel_function To set a timer channel either in compare or in capture mode. Table 21-69. Members Enum value Description TCC_CHANNEL_FUNCTION_COMPARE TCC channel performs compare operation. TCC_CHANNEL_FUNCTION_CAPTURE TCC channel performs capture operation. 21.6.5.3 Enum tcc_clock_prescaler This enum is used to choose the clock prescaler configuration. The prescaler divides the clock frequency of the TCC module to operate TCC at a slower clock rate. Table 21-70. Members Enum value Description TCC_CLOCK_PRESCALER_DIV1 Divide clock by 1. TCC_CLOCK_PRESCALER_DIV2 Divide clock by 2. TCC_CLOCK_PRESCALER_DIV4 Divide clock by 4. TCC_CLOCK_PRESCALER_DIV8 Divide clock by 8. TCC_CLOCK_PRESCALER_DIV16 Divide clock by 16. TCC_CLOCK_PRESCALER_DIV64 Divide clock by 64. TCC_CLOCK_PRESCALER_DIV256 Divide clock by 256. TCC_CLOCK_PRESCALER_DIV1024 Divide clock by 1024. 21.6.5.4 Enum tcc_count_direction Used when selecting the Timer/Counter count direction. Table 21-71. Members Enum value Description TCC_COUNT_DIRECTION_UP Timer should count upward. TCC_COUNT_DIRECTION_DOWN Timer should count downward. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 472 21.6.5.5 Enum tcc_event0_action Event action to perform when the module is triggered by event0. Table 21-72. Members Enum value Description TCC_EVENT0_ACTION_OFF No event action. TCC_EVENT0_ACTION_RETRIGGER Re-trigger Counter on event. TCC_EVENT0_ACTION_COUNT_EVENT Count events (increment or decrement, depending on count direction). TCC_EVENT0_ACTION_START Start counter on event. TCC_EVENT0_ACTION_INCREMENT Increment counter on event. TCC_EVENT0_ACTION_COUNT_DURING_ACTIVE Count during active state of asynchronous event. TCC_EVENT0_ACTION_NON_RECOVERABLE_FAULT Generate Non-Recoverable Fault on event. 21.6.5.6 Enum tcc_event1_action Event action to perform when the module is triggered by event1. Table 21-73. Members Enum value Description TCC_EVENT1_ACTION_OFF No event action. TCC_EVENT1_ACTION_RETRIGGER Re-trigger Counter on event. TCC_EVENT1_ACTION_DIR_CONTROL The event source must be an asynchronous event, input value will override the direction settings. If TCEINVx is 0 and input event is LOW: counter will count up. If TCEINVx is 0 and input event is HIGH: counter will count down. TCC_EVENT1_ACTION_STOP Stop counter on event. TCC_EVENT1_ACTION_DECREMENT Decrement on event. TCC_EVENT1_ACTION_PERIOD_PULSE_WIDTH_CAPTURE Store period in capture register 0, pulse width in capture register 1. TCC_EVENT1_ACTION_PULSE_WIDTH_PERIOD_CAPTURE Store pulse width in capture register 0, period in capture register 1. TCC_EVENT1_ACTION_NON_RECOVERABLE_FAULT Generate Non-Recoverable Fault on event. 21.6.5.7 Enum tcc_event_action Event action to perform when the module is triggered by events. Table 21-74. Members Enum value Description TCC_EVENT_ACTION_OFF No event action. TCC_EVENT_ACTION_STOP Stop counting, the counter will maintain its current value, waveforms are set to a defined Non-Recoverable State output (tcc_non_recoverable_state_output). AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 473 Enum value Description TCC_EVENT_ACTION_RETRIGGER Re-trigger counter on event, may generate an event if the re-trigger event output is enabled. Note When re-trigger event action is enabled, enabling the counter will not start until the next incoming event appears. TCC_EVENT_ACTION_START Start counter when previously stopped. Start counting on the event rising edge. Further events will not restart the counter; the counter keeps on counting using prescaled GCLK_TCCx, until it reaches TOP or Zero depending on the direction. TCC_EVENT_ACTION_COUNT_EVENT Count events; i.e. Increment or decrement depending on count direction. TCC_EVENT_ACTION_DIR_CONTROL The event source must be an asynchronous event, input value will overrides the direction settings (input low: counting up, input high counting down). TCC_EVENT_ACTION_INCREMENT Increment the counter on event, irrespective of count direction. TCC_EVENT_ACTION_DECREMENT Decrement the counter on event, irrespective of count direction. TCC_EVENT_ACTION_COUNT_DURING_ACTIVE Count during active state of asynchronous event. In this case, depending on the count direction, the count will be incremented or decremented on each prescaled GCLK_TCCx, as long as the input event remains active. TCC_EVENT_ACTION_PERIOD_PULSE_WIDTH_CAPTURE Store period in capture register 0, pulse width in capture register 1. TCC_EVENT_ACTION_PULSE_WIDTH_PERIOD_CAPTURE Store pulse width in capture register 0, period in capture register 1. TCC_EVENT_ACTION_NON_RECOVERABLE_FAULT Generate Non-Recoverable Fault on event. 21.6.5.8 Enum tcc_event_generation_selection This enum is used to define the point at which the counter event is generated. Table 21-75. Members Enum value Description TCC_EVENT_GENERATION_SELECTION_START Counter Event is generated when a new counter cycle starts. TCC_EVENT_GENERATION_SELECTION_END Counter Event is generated when a counter cycle ends. TCC_EVENT_GENERATION_SELECTION_BETWEEN Counter Event is generated when a counter cycle ends, except for the first and last cycles. TCC_EVENT_GENERATION_SELECTION_BOUNDARY Counter Event is generated when a new counter cycle starts or ends. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 474 21.6.5.9 Enum tcc_fault_blanking Table 21-76. Members Enum value Description TCC_FAULT_BLANKING_DISABLE No blanking. TCC_FAULT_BLANKING_RISING_EDGE Blanking applied from rising edge of the output waveform. TCC_FAULT_BLANKING_FALLING_EDGE Blanking applied from falling edge of the output waveform. TCC_FAULT_BLANKING_BOTH_EDGE Blanking applied from each toggle of the output waveform. 21.6.5.10 Enum tcc_fault_capture_action Table 21-77. Members Enum value Description TCC_FAULT_CAPTURE_DISABLE Capture disabled. TCC_FAULT_CAPTURE_EACH Capture on Fault, each value is captured. TCC_FAULT_CAPTURE_MINIMUM Capture the minimum detection, but notify on smaller ones. TCC_FAULT_CAPTURE_MAXIMUM Capture the maximum detection, but notify on bigger ones. TCC_FAULT_CAPTURE_SMALLER Capture if the value is smaller than last, notify event or interrupt if previous stamp is confirmed to be "local minimum" (not bigger than current stamp). TCC_FAULT_CAPTURE_BIGGER Capture if the value is bigger than last, notify event or interrupt if previous stamp is confirmed to be "local maximum" (not smaller than current stamp). TCC_FAULT_CAPTURE_CHANGE Capture if the time stamps changes its increment direction. 21.6.5.11 Enum tcc_fault_capture_channel Table 21-78. Members Enum value Description TCC_FAULT_CAPTURE_CHANNEL_0 Recoverable fault triggers channel 0 capture operation. TCC_FAULT_CAPTURE_CHANNEL_1 Recoverable fault triggers channel 1 capture operation. TCC_FAULT_CAPTURE_CHANNEL_2 Recoverable fault triggers channel 2 capture operation. TCC_FAULT_CAPTURE_CHANNEL_3 Recoverable fault triggers channel 3 capture operation. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 475 21.6.5.12 Enum tcc_fault_halt_action Table 21-79. Members Enum value Description TCC_FAULT_HALT_ACTION_DISABLE Halt action disabled. TCC_FAULT_HALT_ACTION_HW_HALT Hardware halt action, counter is halted until restart. TCC_FAULT_HALT_ACTION_SW_HALT Software halt action, counter is halted until fault bit cleared. TCC_FAULT_HALT_ACTION_NON_RECOVERABLE Non-Recoverable fault, force output to predefined level. 21.6.5.13 Enum tcc_fault_keep Table 21-80. Members Enum value Description TCC_FAULT_KEEP_DISABLE Disable keeping, wave output released as soon as fault is released. TCC_FAULT_KEEP_TILL_END Keep wave output until end of TCC cycle. 21.6.5.14 Enum tcc_fault_qualification Table 21-81. Members Enum value Description TCC_FAULT_QUALIFICATION_DISABLE The input is not disabled on compare condition. TCC_FAULT_QUALIFICATION_BY_OUTPUT The input is disabled when match output signal is at inactive level. 21.6.5.15 Enum tcc_fault_restart Table 21-82. Members Enum value Description TCC_FAULT_RESTART_DISABLE Restart Action disabled. TCC_FAULT_RESTART_ENABLE Restart Action enabled. 21.6.5.16 Enum tcc_fault_source Table 21-83. Members Enum value Description TCC_FAULT_SOURCE_DISABLE Fault input is disabled. TCC_FAULT_SOURCE_ENABLE Match Capture Event x (x=0,1) input. TCC_FAULT_SOURCE_INVERT Inverted MCEx (x=0,1) event input. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 476 Enum value Description TCC_FAULT_SOURCE_ALTFAULT Alternate fault (A or B) state at the end of the previous period. 21.6.5.17 Enum tcc_fault_state_output Table 21-84. Members Enum value Description TCC_FAULT_STATE_OUTPUT_OFF Non-recoverable fault output is tri-stated. TCC_FAULT_STATE_OUTPUT_0 Non-recoverable fault force output 0. TCC_FAULT_STATE_OUTPUT_1 Non-recoverable fault force output 1. 21.6.5.18 Enum tcc_match_capture_channel This enum is used to specify which capture/match channel to do operations on. Table 21-85. Members Enum value Description TCC_MATCH_CAPTURE_CHANNEL_n Match capture channel index table for TCC Each TCC module may contain several match capture channels; each channel will have its own index in the table, with the index number substituted for "n" in the index name (e.g. TCC_MATCH_CAPTURE_CHANNEL_0). 21.6.5.19 Enum tcc_output_invertion Used when enabling or disabling output inversion. Table 21-86. Members Enum value Description TCC_OUTPUT_INVERTION_DISABLE Output inversion not to be enabled. TCC_OUTPUT_INVERTION_ENABLE Invert the output from WO[x]. 21.6.5.20 Enum tcc_output_pattern Used when disabling output pattern or when selecting a specific pattern. Table 21-87. Members Enum value Description TCC_OUTPUT_PATTERN_DISABLE SWAP output pattern is not used. TCC_OUTPUT_PATTERN_0 Pattern 0 is applied to SWAP output. TCC_OUTPUT_PATTERN_1 Pattern 1 is applied to SWAP output. 21.6.5.21 Enum tcc_ramp AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 477 Ramp operations which are supported in single-slope PWM generation. Table 21-88. Members Enum value Description TCC_RAMP_RAMP1 Default timer/counter PWM operation. TCC_RAMP_RAMP2A Uses a single channel (CC0) to control both CC0/CC1 compare outputs. In cycle A, the channel 0 output is disabled, and in cycle B, the channel 1 output is disabled. TCC_RAMP_RAMP2 Uses channels CC0 and CC1 to control compare outputs. In cycle A, the channel 0 output is disabled, and in cycle B, the channel 1 output is disabled. 21.6.5.22 Enum tcc_ramp_index In ramp operation, each two period cycles are marked as cycle A and B, the index 0 represents cycle A and 1 represents cycle B. Table 21-89. Members Enum value Description TCC_RAMP_INDEX_DEFAULT Default, cycle index toggles. TCC_RAMP_INDEX_FORCE_B Force next cycle to be cycle B (set to 1). TCC_RAMP_INDEX_FORCE_A Force next cycle to be cycle A (clear to 0). TCC_RAMP_INDEX_FORCE_KEEP Force next cycle keeping the same as current. 21.6.5.23 Enum tcc_reload_action This enum specify how the counter is reloaded and whether the prescaler should be restarted. Table 21-90. Members Enum value Description TCC_RELOAD_ACTION_GCLK The counter is reloaded/reset on the next GCLK and starts counting on the prescaler clock. TCC_RELOAD_ACTION_PRESC The counter is reloaded/reset on the next prescaler clock. TCC_RELOAD_ACTION_RESYNC The counter is reloaded/reset on the next GCLK, and the prescaler is restarted as well. 21.6.5.24 Enum tcc_wave_generation This enum is used to specify the waveform generation mode. Table 21-91. Members Enum value Description TCC_WAVE_GENERATION_NORMAL_FREQ Normal Frequency: Top is the PER register, output toggled on each compare match. TCC_WAVE_GENERATION_MATCH_FREQ Match Frequency: Top is CC0 register, output toggles on each update condition. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 478 Enum value Description TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM Single-Slope PWM: Top is the PER register, CCx controls duty cycle ( output active when count is greater than CCx). TCC_WAVE_GENERATION_DOUBLE_SLOPE_CRITICAL Double-slope (count up and down), non centrealigned: Top is the PER register, CC[x] controls duty cycle while counting up and CC[x+N/2] controls it while counting down. TCC_WAVE_GENERATION_DOUBLE_SLOPE_BOTTOM Double-slope (count up and down), interrupt/ event at Bottom (Top is the PER register, output active when count is greater than CCx). TCC_WAVE_GENERATION_DOUBLE_SLOPE_BOTH Double-slope (count up and down), interrupt/ event at Bottom and Top: (Top is the PER register, output active when count is lower than CCx). TCC_WAVE_GENERATION_DOUBLE_SLOPE_TOP Double-slope (count up and down), interrupt/ event at Top (Top is the PER register, output active when count is greater than CCx). 21.6.5.25 Enum tcc_wave_output This enum is used to specify which wave output to do operations on. Table 21-92. Members Enum value Description TCC_WAVE_OUTPUT_n Waveform output index table for TCC Each TCC module may contain several wave outputs; each output will have its own index in the table, with the index number substituted for "n" in the index name (e.g. TCC_WAVE_OUTPUT_0). 21.6.5.26 Enum tcc_wave_polarity Specifies whether the wave output needs to be inverted or not. Table 21-93. Members Enum value Description TCC_WAVE_POLARITY_0 Wave output is not inverted. TCC_WAVE_POLARITY_1 Wave output is inverted. 21.7 Extra Information for TCC Driver 21.7.1 Acronyms The table below presents the acronyms used in this module: Acronym Description DMA Direct Memory Access AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 479 21.7.2 Acronym Description TCC Timer Counter for Control Applications PWM Pulse Width Modulation PWP Pulse Width Period PPW Period Pulse Width Dependencies This driver has the following dependencies: ● 21.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 21.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add double buffering functionality Add fault handling functionality Initial Release 21.8 Examples for TCC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Timer Counter for Control Applications Driver (TCC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. 21.8.1 ● Quick Start Guide for TCC - Basic ● Quick Start Guide for TCC - Double Buffering and Circular ● Quick Start Guide for TCC - Timer ● Quick Start Guide for TCC - Callback ● Quick Start Guide for TCC - Non-Recoverable Fault ● Quick Start Guide for TCC - Recoverable Fault ● Quick Start Guide for Using DMA with TCC Quick Start Guide for TCC - Basic The supported board list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal. Here the pulse width is set to one quarter of the period. When connect PWM output to LED it makes the LED light. To see the waveform, you may need an oscilloscope. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 480 The PWM output is set up as follows: Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMR21 Xpro PA19 LED0 SAML21 Xpro PB10 LED0 The TCC module will be set up as follows: ● GCLK generator 0 (GCLK main) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● No prescaler ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No fault or waveform extensions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● No event input enabled ● No event action ● No event generation enabled ● Counter starts on 0 ● Counter top set to 0xFFFF ● Capture compare channel 0 set to 0xFFFF/4 21.8.1.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions: #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 481 #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = (0xFFFF / 4); config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); tcc_enable(&tcc_instance); } Add to user application initialization (typically the start of main()): configure_tcc(); Workflow 1. Create a module software instance structure for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the TCC module. a. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. struct tcc_config config_tcc; b. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 482 Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value. config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = (0xFFFF / 4); d. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; e. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); f. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 21.8.1.2 Use Case Code Copy-paste the following code to your user application: while (true) { /* Infinite loop */ } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. while (true) { /* Infinite loop */ } 21.8.2 Quick Start Guide for TCC - Double Buffering and Circular The supported board list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal. Here the pulse width alters in one quarter and three quarter of the period. When connect PWM output to LED it makes the LED light. To see the waveform, you may need an oscilloscope. The PWM output is set up as follows: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 483 Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMR21 Xpro PA19 LED0 SAML21 Xpro PB10 LED0 The TCC module will be set up as follows: ● GCLK generator 0 (GCLK main) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● Prescaler is set to 1024 ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No fault or waveform extensions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● No event input enabled ● No event action ● No event generation enabled ● Counter starts on 0 ● Counter top set to 8000 ● Capture compare channel set to 8000/4 ● Capture compare channel buffer set to 8000*3/4 ● Circular option for compare channel is enabled so that the compare values keep switching on update condition 21.8.2.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions: #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 484 #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.clock_prescaler = TCC_CLOCK_PRESCALER_DIV1024; config_tcc.counter.period = 8000; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = (8000 / 4); config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); tcc_set_compare_value(&tcc_instance, (enum tcc_match_capture_channel)CONF_PWM_CHANNEL, 8000*3/4); tcc_enable_circular_buffer_compare(&tcc_instance, (enum tcc_match_capture_channel)CONF_PWM_CHANNEL); tcc_enable(&tcc_instance); } Add to user application initialization (typically the start of main()): configure_tcc(); Workflow 1. Create a module software instance structure for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the TCC module. a. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 485 struct tcc_config config_tcc; b. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value. config_tcc.counter.clock_prescaler = TCC_CLOCK_PRESCALER_DIV1024; config_tcc.counter.period = 8000; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = (8000 / 4); d. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; e. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); f. Set to compare buffer value and enable circular of double buffered compare values. tcc_set_compare_value(&tcc_instance, (enum tcc_match_capture_channel)CONF_PWM_CHANNEL, 8000*3/4); tcc_enable_circular_buffer_compare(&tcc_instance, (enum tcc_match_capture_channel)CONF_PWM_CHANNEL); g. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 21.8.2.2 Use Case Code Copy-paste the following code to your user application: while (true) { /* Infinite loop */ } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 486 while (true) { /* Infinite loop */ } 21.8.3 Quick Start Guide for TCC - Timer The supported board list: ● SAM D21/R21/L21 Xplained Pro ● SAM D11 Xplained Pro In this use case, the TCC will be used as a timer, to generate overflow and compare match callbacks. In the callbacks the on-board LED is toggled. The TCC module will be set up as follows: ● GCLK generator 1 (GCLK 32K) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● Prescaler is divided by 64 ● GCLK reload action ● Count upward ● Don't run in standby ● No waveform outputs ● No capture enabled ● Don't perform one-shot operations ● No event input enabled ● No event action ● No event generation enabled ● Counter starts on 0 ● Counter top set to 2000 (about 4s) and generate overflow callback ● Channel 0 is set to compare and match value 900 and generate callback ● Channel 1 is set to compare and match value 930 and generate callback ● Channel 2 is set to compare and match value 1100 and generate callback ● Channel 3 is set to compare and match value 1250 and generate callback 21.8.3.1 Quick Start Prerequisites For this use case, XOSC32K should be enabled and available through GCLK generator 1 clock source selection. Within Atmel Software Framework (ASF) it can be done through modifying conf_clocks.h. See System Clock Management Driver for more details about clock configuration. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 487 Code Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; Copy-paste the following callback function code to your user application: static void tcc_callback_to_toggle_led( struct tcc_module *const module_inst) { port_pin_toggle_output_level(LED0_PIN); } Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, TCC0); config_tcc.counter.clock_source = GCLK_GENERATOR_1; config_tcc.counter.clock_prescaler = TCC_CLOCK_PRESCALER_DIV64; config_tcc.counter.period = 2000; config_tcc.compare.match[0] = 900; config_tcc.compare.match[1] = 930; config_tcc.compare.match[2] = 1100; config_tcc.compare.match[3] = 1250; tcc_init(&tcc_instance, TCC0, &config_tcc); } tcc_enable(&tcc_instance); static void configure_tcc_callbacks(void) { tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_OVERFLOW); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_CHANNEL_0); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_CHANNEL_1); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_CHANNEL_2); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_CHANNEL_3); } tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, TCC_CALLBACK_OVERFLOW); TCC_CALLBACK_CHANNEL_0); TCC_CALLBACK_CHANNEL_1); TCC_CALLBACK_CHANNEL_2); TCC_CALLBACK_CHANNEL_3); Add to user application initialization (typically the start of main()): configure_tcc(); configure_tcc_callbacks(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 488 Workflow 1. Create a module software instance structure for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the TCC module. a. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. struct tcc_config config_tcc; b. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, TCC0); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the TCC settings to configure the GCLK source, prescaler, period and compare channel values. config_tcc.counter.clock_source = GCLK_GENERATOR_1; config_tcc.counter.clock_prescaler = TCC_CLOCK_PRESCALER_DIV64; config_tcc.counter.period = 2000; config_tcc.compare.match[0] = 900; config_tcc.compare.match[1] = 930; config_tcc.compare.match[2] = 1100; config_tcc.compare.match[3] = 1250; d. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, TCC0, &config_tcc); e. Enable the TCC module to start the timer. tcc_enable(&tcc_instance); 3. Configure the TCC callbacks. a. Register the Overflow and Compare Channel Match callback functions with the driver. tcc_register_callback(&tcc_instance, TCC_CALLBACK_OVERFLOW); tcc_register_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_0); tcc_register_callback(&tcc_instance, TCC_CALLBACK_CHANNEL_1); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, tcc_callback_to_toggle_led, tcc_callback_to_toggle_led, tcc_callback_to_toggle_led, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 489 TCC_CALLBACK_CHANNEL_2); tcc_register_callback(&tcc_instance, tcc_callback_to_toggle_led, TCC_CALLBACK_CHANNEL_3); b. Enable the Overflow and Compare Channel Match callbacks so that it will be called by the driver when appropriate. tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, tcc_enable_callback(&tcc_instance, TCC_CALLBACK_OVERFLOW); TCC_CALLBACK_CHANNEL_0); TCC_CALLBACK_CHANNEL_1); TCC_CALLBACK_CHANNEL_2); TCC_CALLBACK_CHANNEL_3); 21.8.3.2 Use Case Code Copy-paste the following code to your user application: system_interrupt_enable_global(); while (true) { } Workflow 1. Enter an infinite loop while the timer is running. while (true) { } 21.8.4 Quick Start Guide for TCC - Callback The supported board list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal, with a varying duty cycle. Here the pulse width is increased each time the timer count matches the set compare value. When connect PWM output to LED it makes the LED vary its light. To see the waveform, you may need an oscilloscope. The PWM output is set up as follows: Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMR21 Xpro PA19 LED0 SAML21 Xpro PB10 LED0 The TCC module will be set up as follows: ● GCLK generator 0 (GCLK main) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● No prescaler AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 490 ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No faults or waveform extensions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● No event input enabled ● No event action ● No event generation enabled ● Counter starts on 0 21.8.4.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions: #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; Copy-paste the following callback function code to your user application: static void tcc_callback_to_change_duty_cycle( struct tcc_module *const module_inst) { static uint32_t delay = 10; static uint32_t i = 0; if (--delay) { return; } delay = 10; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 491 i = (i + 0x0800) & 0xFFFF; tcc_set_compare_value(module_inst, (enum tcc_match_capture_channel) (TCC_MATCH_CAPTURE_CHANNEL_0 + CONF_PWM_CHANNEL), i + 1); } Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); tcc_enable(&tcc_instance); } static void configure_tcc_callbacks(void) { tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); } Add to user application initialization (typically the start of main()): configure_tcc(); configure_tcc_callbacks(); Workflow 1. Create a module software instance structure for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Configure the TCC module. a. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 492 struct tcc_config config_tcc; b. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value. config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; d. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; e. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); f. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 3. Configure the TCC callbacks. a. Register the Compare Channel 0 Match callback functions with the driver. tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); b. Enable the Compare Channel 0 Match callback so that it will be called by the driver when appropriate. tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); 21.8.4.2 Use Case Code Copy-paste the following code to your user application: system_interrupt_enable_global(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 493 while (true) { } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. while (true) { } 21.8.5 Quick Start Guide for TCC - Non-Recoverable Fault The supported kit list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal, with a varying duty cycle. Here the pulse width is increased each time the timer count matches the set compare value. There is a non-recoverable faul input which controls PWM output, when this fault is active (low) the PWM output will be forced to be high. When fault is released (input high) the PWM output then will go on. When connect PWM output to LED it makes the LED vary its light. If fault input is from a button, the LED will be off when the button is down and on when the button is up. To see the PWM waveform, you may need an oscilloscope. The PWM output and fault input is set up as follows: Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMD21 Xpro PA15 SW0 SAMR21 Xpro PA19 LED0 SAMR21 Xpro PA28 SW0 SAML21 Xpro PB10 LED0 The TCC module will be set up as follows: ● GCLK generator 0 (GCLK main) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● No prescaler ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No waveform extentions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● No event input except TCC event0 enabled AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 494 ● No event action except TCC event0 acts as Non-Recoverable Fault ● No event generation enabled ● Counter starts on 0 21.8.5.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions: ● SAM D21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_15 #define CONF_FAULT_EVENT_USER ● EVSYS_ID_USER_TCC0_EV_0 SAM R21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_8 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 495 #define CONF_FAULT_EVENT_USER ● EVSYS_ID_USER_TCC0_EV_0 SAM L21 Xplained Pro: #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_15 #define CONF_FAULT_EVENT_USER EVSYS_ID_USER_TCC0_EV_0 Add to the main application source file, before any functions: #include <string.h> Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; struct events_resource event_resource; Copy-paste the following callback function code to your user application: static void tcc_callback_to_change_duty_cycle( struct tcc_module *const module_inst) { static uint32_t delay = 10; static uint32_t i = 0; } if (--delay) { return; } delay = 10; i = (i + 0x0800) & 0xFFFF; tcc_set_compare_value(module_inst, (enum tcc_match_capture_channel) (TCC_MATCH_CAPTURE_CHANNEL_0 + CONF_PWM_CHANNEL), i + 1); static void eic_callback_to_clear_halt(void) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 496 { } if (port_pin_get_input_level(CONF_FAULT_EIC_PIN)) { tcc_clear_status(&tcc_instance, TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT(0) | TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR(0)); } Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; config_tcc.wave_ext.non_recoverable_fault[0].output = TCC_FAULT_STATE_OUTPUT_1; config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); struct tcc_events events; memset(&events, 0, sizeof(struct tcc_events)); events.on_input_event_perform_action[0] = true; events.input_config[0].modify_action = true; events.input_config[0].action = TCC_EVENT_ACTION_NON_RECOVERABLE_FAULT; tcc_enable_events(&tcc_instance, &events); } tcc_enable(&tcc_instance); static void configure_tcc_callbacks(void) { tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); } tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); static void configure_eic(void) { struct extint_chan_conf config; extint_chan_get_config_defaults(&config); config.filter_input_signal = true; config.detection_criteria = EXTINT_DETECT_BOTH; config.gpio_pin = CONF_FAULT_EIC_PIN; config.gpio_pin_mux = CONF_FAULT_EIC_PIN_MUX; extint_chan_set_config(CONF_FAULT_EIC_LINE, &config); struct extint_events events; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 497 memset(&events, 0, sizeof(struct extint_events)); events.generate_event_on_detect[CONF_FAULT_EIC_LINE] = true; extint_enable_events(&events); } extint_register_callback(eic_callback_to_clear_halt, CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); extint_chan_enable_callback(CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); static void configure_event(void) { struct events_config config; events_get_config_defaults(&config); config.generator = CONF_FAULT_EVENT_GENERATOR; config.path = EVENTS_PATH_ASYNCHRONOUS; events_allocate(&event_resource, &config); } events_attach_user(&event_resource, CONF_FAULT_EVENT_USER); Add to user application initialization (typically the start of main()): configure_tcc(); configure_tcc_callbacks(); configure_eic(); configure_event(); Workflow Configure TCC 1. Create a module software instance struct for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. struct tcc_config config_tcc; 3. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 498 Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value and fault options. Here the Non-Recoverable Fault output is enabled and set to high level (1). config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; config_tcc.wave_ext.non_recoverable_fault[0].output = TCC_FAULT_STATE_OUTPUT_1; 5. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; 6. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); 7. Create a TCC events configuration struct, which can be filled out to enable/disable events and configure event settings. Reset all fields to zero. struct tcc_events events; memset(&events, 0, sizeof(struct tcc_events)); 8. Alter the TCC events settings to enable/disable desired events, to change event generating options and modify event actions. Here TCC event0 will act as Non-Recoverable Fault input. events.on_input_event_perform_action[0] = true; events.input_config[0].modify_action = true; events.input_config[0].action = TCC_EVENT_ACTION_NON_RECOVERABLE_FAULT; 9. Enable and apply events settings. tcc_enable_events(&tcc_instance, &events); 10. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 11. Register the Compare Channel 0 Match callback functions with the driver. tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 499 12. Enable the Compare Channel 0 Match callback so that it will be called by the driver when appropriate. tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); Configure EXTINT for fault input 1. Create an EXTINT module channel configuration struct, which can be filled out to adjust the configuration of a single external interrupt channel. struct extint_chan_conf config; 2. Initialize the channel configuration struct with the module's default values. extint_chan_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to configure the pin MUX (to route the desired physical pin to the logical channel) to the board button, and to configure the channel to detect both rising and falling edges. config.filter_input_signal = true; config.detection_criteria = EXTINT_DETECT_BOTH; config.gpio_pin = CONF_FAULT_EIC_PIN; config.gpio_pin_mux = CONF_FAULT_EIC_PIN_MUX; 4. Configure external interrupt channel with the desired channel settings. extint_chan_set_config(CONF_FAULT_EIC_LINE, &config); 5. Create a TXTINT events configuration struct, which can be filled out to enable/disable events. Reset all fields to zero. struct extint_events events; memset(&events, 0, sizeof(struct extint_events)); 6. Adjust the configuration struct, set the channels to be enabled to true. Here the channel to the board button is used. events.generate_event_on_detect[CONF_FAULT_EIC_LINE] = true; 7. Enable the events. extint_enable_events(&events); 8. Define the EXTINT callback that will be fired when a detection event occurs. For this example, when fault line is released, the TCC fault state is cleared to go on PWM generating. static void eic_callback_to_clear_halt(void) { AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 500 } 9. if (port_pin_get_input_level(CONF_FAULT_EIC_PIN)) { tcc_clear_status(&tcc_instance, TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT(0) | TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR(0)); } Register a callback function eic_callback_to_clear_halt() to handle detections from the External Interrupt Controller (EIC). extint_register_callback(eic_callback_to_clear_halt, CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); 10. Enable the registered callback function for the configured External Interrupt channel, so that it will be called by the module when the channel detects an edge. extint_chan_enable_callback(CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); Configure EVENTS for fault input 1. Create a event resource instance struct for the EVENTS module to store. struct events_resource event_resource; Note This should never go out of scope as long as the resource is in use. In most cases, this should be global. 2. Create an event channel configuration struct, which can be filled out to adjust the configuration of a single event channel. struct events_config config; 3. Initialize the event channel configuration struct with the module's default values. events_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Adjust the configuration struct to request that the channel be attached to the specified event generator, and that the asynchronous event path be used. Here the EIC channel connected to board button is the event generator. config.generator = CONF_FAULT_EVENT_GENERATOR; config.path = EVENTS_PATH_ASYNCHRONOUS; 5. Allocate and configure the channel using the configuration structure. events_allocate(&event_resource, &config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 501 Note The existing configuration struct may be re-used, as long as any values that have been altered from the default settings are taken into account by the user application. 6. Attach an user to the channel. Here the user is TCC event0, which has been configured as input of NonRecoverable Fault. events_attach_user(&event_resource, CONF_FAULT_EVENT_USER); 21.8.5.2 Use Case Code Copy-paste the following code to your user application: system_interrupt_enable_global(); while (true) { } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. while (true) { } 21.8.6 Quick Start Guide for TCC - Recoverable Fault The supported board list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal, with a varying duty cycle. Here the pulse width is increased each time the timer count matches the set compare value. There is a recoverable faul input which controls PWM output, when this fault is active (low) the PWM output will be frozen (could be off or on, no light changing). When fault is released (input high) the PWM output then will go on. When connect PWM output to LED it makes the LED vary its light. If fault input is from a button, the LED will be frozen and not changing it's light when the button is down and will go on when the button is up. To see the PWM waveform, you may need an oscilloscope. The PWM output and fault input is set up as follows: Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMD21 Xpro PA15 SW0 SAMR21 Xpro PA06 EXT1 Pin 3 SAMR21 Xpro PA28 SW0 SAML21 Xpro PB10 LED0 The TCC module will be set up as follows: ● GCLK generator 0 (GCLK main) clock source AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 502 ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● No prescaler ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No waveform extentions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● No event input except channel 0 event enabled ● No event action ● No event generation enabled ● Counter starts on 0 ● Recoverable Fault A is generated from channel 0 event input, fault halt acts as software halt, other actions or options are all disabled 21.8.6.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions, according to the kit used: ● SAM D21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_15 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 503 #define CONF_FAULT_EVENT_USER ● EVSYS_ID_USER_TCC0_MC_0 SAM R21 Xplained Pro. #define CONF_PWM_MODULE TCC1 #define CONF_PWM_CHANNEL 0 #define CONF_PWM_OUTPUT 0 #define CONF_PWM_OUT_PIN PIN_PA06E_TCC1_WO0 #define CONF_PWM_OUT_MUX MUX_PA06E_TCC1_WO0 #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_8 #define CONF_FAULT_EVENT_USER ● EVSYS_ID_USER_TCC1_MC_0 SAM L21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_FAULT_EIC_PIN SW0_EIC_PIN #define CONF_FAULT_EIC_PIN_MUX SW0_EIC_PINMUX #define CONF_FAULT_EIC_LINE SW0_EIC_LINE #define CONF_FAULT_EVENT_GENERATOR EVSYS_ID_GEN_EIC_EXTINT_8 #define CONF_FAULT_EVENT_USER EVSYS_ID_USER_TCC1_MC_0 Add to the main application source file, before any functions: #include <string.h> Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 504 struct events_resource event_resource; Copy-paste the following callback function code to your user application: static void tcc_callback_to_change_duty_cycle( struct tcc_module *const module_inst) { static uint32_t delay = 10; static uint32_t i = 0; } if (--delay) { return; } delay = 10; i = (i + 0x0800) & 0xFFFF; tcc_set_compare_value(module_inst, (enum tcc_match_capture_channel) (TCC_MATCH_CAPTURE_CHANNEL_0 + CONF_PWM_CHANNEL), i + 1); static void eic_callback_to_clear_halt(void) { if (port_pin_get_input_level(CONF_FAULT_EIC_PIN)) { tcc_clear_status(&tcc_instance, TCC_STATUS_RECOVERABLE_FAULT_PRESENT(CONF_PWM_CHANNEL) | TCC_STATUS_RECOVERABLE_FAULT_OCCUR(CONF_PWM_CHANNEL)); } } Copy-paste the following setup code to your user application: static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; config_tcc.wave_ext.recoverable_fault[CONF_PWM_CHANNEL].source = TCC_FAULT_SOURCE_ENABLE; config_tcc.wave_ext.recoverable_fault[CONF_PWM_CHANNEL].halt_action = TCC_FAULT_HALT_ACTION_SW_HALT; config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); struct tcc_events events; memset(&events, 0, sizeof(struct tcc_events)); events.on_event_perform_channel_action[CONF_PWM_CHANNEL] = true; tcc_enable_events(&tcc_instance, &events); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 505 } tcc_enable(&tcc_instance); static void configure_tcc_callbacks(void) { tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); } tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); static void configure_eic(void) { struct extint_chan_conf config; extint_chan_get_config_defaults(&config); config.filter_input_signal = true; config.detection_criteria = EXTINT_DETECT_BOTH; config.gpio_pin = CONF_FAULT_EIC_PIN; config.gpio_pin_mux = CONF_FAULT_EIC_PIN_MUX; extint_chan_set_config(CONF_FAULT_EIC_LINE, &config); struct extint_events events; memset(&events, 0, sizeof(struct extint_events)); events.generate_event_on_detect[CONF_FAULT_EIC_LINE] = true; extint_enable_events(&events); } extint_register_callback(eic_callback_to_clear_halt, CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); extint_chan_enable_callback(CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); static void configure_event(void) { struct events_config config; events_get_config_defaults(&config); config.generator = CONF_FAULT_EVENT_GENERATOR; config.path = EVENTS_PATH_ASYNCHRONOUS; events_allocate(&event_resource, &config); } events_attach_user(&event_resource, CONF_FAULT_EVENT_USER); Add to user application initialization (typically the start of main()): configure_tcc(); configure_tcc_callbacks(); configure_eic(); configure_event(); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 506 Workflow Configure TCC 1. Create a module software instance struct for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. struct tcc_config config_tcc; 3. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value and fault options. Here the Recoverable Fault input is enabled and halt action is set to software mode (must use software to clear halt state). config_tcc.counter.period = 0xFFFF; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.match[CONF_PWM_CHANNEL] = 0xFFFF; config_tcc.wave_ext.recoverable_fault[CONF_PWM_CHANNEL].source = TCC_FAULT_SOURCE_ENABLE; config_tcc.wave_ext.recoverable_fault[CONF_PWM_CHANNEL].halt_action = TCC_FAULT_HALT_ACTION_SW_HALT; 5. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; 6. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); 7. Create a TCC events configuration struct, which can be filled out to enable/disable events and configure event settings. Reset all fields to zero. struct tcc_events events; memset(&events, 0, sizeof(struct tcc_events)); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 507 8. Alter the TCC events settings to enable/disable desired events, to change event generating options and modify event actions. Here channel event 0 input is enabled as source of recoverable fault. events.on_event_perform_channel_action[CONF_PWM_CHANNEL] = true; 9. Enable and apply events settings. tcc_enable_events(&tcc_instance, &events); 10. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 11. Register the Compare Channel 0 Match callback functions with the driver. tcc_register_callback( &tcc_instance, tcc_callback_to_change_duty_cycle, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); 12. Enable the Compare Channel 0 Match callback so that it will be called by the driver when appropriate. tcc_enable_callback(&tcc_instance, (enum tcc_callback)(TCC_CALLBACK_CHANNEL_0 + CONF_PWM_CHANNEL)); Configure EXTINT for fault input 1. Create an EXTINT module channel configuration struct, which can be filled out to adjust the configuration of a single external interrupt channel. struct extint_chan_conf config; 2. Initialize the channel configuration struct with the module's default values. extint_chan_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to configure the pin MUX (to route the desired physical pin to the logical channel) to the board button, and to configure the channel to detect both rising and falling edges. config.filter_input_signal = true; config.detection_criteria = EXTINT_DETECT_BOTH; config.gpio_pin = CONF_FAULT_EIC_PIN; config.gpio_pin_mux = CONF_FAULT_EIC_PIN_MUX; 4. Configure external interrupt channel with the desired channel settings. extint_chan_set_config(CONF_FAULT_EIC_LINE, &config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 508 5. Create a TXTINT events configuration struct, which can be filled out to enable/disable events. Reset all fields to zero. struct extint_events events; memset(&events, 0, sizeof(struct extint_events)); 6. Adjust the configuration struct, set the channels to be enabled to true. Here the channel to the board button is used. events.generate_event_on_detect[CONF_FAULT_EIC_LINE] = true; 7. Enable the events. extint_enable_events(&events); 8. Define the EXTINT callback that will be fired when a detection event occurs. For this example, when fault line is released, the TCC fault state is cleared to go on PWM generating. static void eic_callback_to_clear_halt(void) { if (port_pin_get_input_level(CONF_FAULT_EIC_PIN)) { tcc_clear_status(&tcc_instance, TCC_STATUS_RECOVERABLE_FAULT_PRESENT(CONF_PWM_CHANNEL) | TCC_STATUS_RECOVERABLE_FAULT_OCCUR(CONF_PWM_CHANNEL)); } } 9. Register a callback function eic_callback_to_clear_halt() to handle detections from the External Interrupt Controller (EIC). extint_register_callback(eic_callback_to_clear_halt, CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); 10. Enable the registered callback function for the configured External Interrupt channel, so that it will be called by the module when the channel detects an edge. extint_chan_enable_callback(CONF_FAULT_EIC_LINE, EXTINT_CALLBACK_TYPE_DETECT); Configure EVENTS for fault input 1. Create a event resource instance struct for the EVENTS module to store. struct events_resource event_resource; Note This should never go out of scope as long as the resource is in use. In most cases, this should be global. 2. Create an event channel configuration struct, which can be filled out to adjust the configuration of a single event channel. struct events_config config; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 509 3. Initialize the event channel configuration struct with the module's default values. events_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Adjust the configuration struct to request that the channel be attached to the specified event generator, and that the asynchronous event path be used. Here the EIC channel connected to board button is the event generator. config.generator = CONF_FAULT_EVENT_GENERATOR; config.path = EVENTS_PATH_ASYNCHRONOUS; 5. Allocate and configure the channel using the configuration structure. events_allocate(&event_resource, &config); Note The existing configuration struct may be re-used, as long as any values that have been altered from the default settings are taken into account by the user application. 6. Attach an user to the channel. Here the user is TCC channel 0 event, which has been configured as input of Recoverable Fault. events_attach_user(&event_resource, CONF_FAULT_EVENT_USER); 21.8.6.2 Use Case Code Copy-paste the following code to your user application: system_interrupt_enable_global(); while (true) { } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. while (true) { } 21.8.7 Quick Start Guide for Using DMA with TCC The supported board list: ● SAM D21/R21/L21 Xplained Pro In this use case, the TCC will be used to generate a PWM signal. Here the pulse width varies through following values with the help of DMA transfer: one quarter of the period, half of the period, and three quarters of the period. The PWM output can be used to drive an LED. The waveform can also be viewed using an oscilloscope. The output signal is also fed back to another TCC channel by event system, the event stamps are captured and transferred to a buffer by DMA. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 510 The PWM output is set up as follows: Board Pin Connect to SAMD21 Xpro PB30 LED0 SAMR21 Xpro PA19 LED0 SAML21 Xpro PB10 LED0 The TCC module will be setup as follows: ● GCLK generator 0 (GCLK main) clock source ● Use double buffering write when set top, compare, or pattern through API ● No dithering on the counter or compare ● No prescaler ● Single Slope PWM wave generation ● GCLK reload action ● Don't run in standby ● No fault or waveform extensions ● No inversion of waveform output ● No capture enabled ● Count upward ● Don't perform one-shot operations ● Counter starts on 0 ● Counter top set to 0x1000 ● Channel 0 (on SAM D21 Xpro) or 3 (on SAM R21 Xpro) is set to compare and match value 0x1000*3/4 and generate event ● Channel 1 is set to capture on input event The event resource of EVSYS module will be setup as follows: ● TCC match capture channel 0 (on SAM D21 Xpro) or 3 (on SAM R21 Xpro) is selected as event generator ● Event generation is synchronous, with rising edge detected ● TCC match capture channel 1 is the event user The DMA resource of DMAC module will be setup as follows: ● Two DMA resources are used ● Both DMA resources use peripheral trigger ● Both DMA resources perform beat transfer on trigger ● Both DMA resources use beat size of 16 bits ● Both DMA resources are configured to transfer three beats and then repeat again in same buffer ● On DMA resource which controls the compare value ● TCC0 overflow triggers DMA transfer ● The source address increment is enabled AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 511 ● ● The destination address is fixed to TCC channel 0 Compare/Capture register On DMA resource which reads the captured value ● TCC0 capture on channel 1 triggers DMA transfer ● The source address is fixed to TCC channel 1 Compare/Capture register ● The destination address increment is enabled ● The captured value is transferred to an array in SRAM 21.8.7.1 Quick Start Prerequisites There are no prerequisites for this use case. Code Add to the main application source file, before any functions, according to the kit used: ● SAM D21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_TCC_CAPTURE_CHANNEL 1 #define CONF_TCC_EVENT_GENERATOR EVSYS_ID_GEN_TCC0_MCX_0 #define CONF_TCC_EVENT_USER EVSYS_ID_USER_TCC0_MC_1 #define CONF_COMPARE_TRIGGER TCC0_DMAC_ID_OVF #define CONF_CAPTURE_TRIGGER TCC0_DMAC_ID_MC_1 ● SAM R21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_TCC_CAPTURE_CHANNEL 1 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 512 #define CONF_TCC_EVENT_GENERATOR EVSYS_ID_GEN_TCC0_MCX_3 #define CONF_TCC_EVENT_USER EVSYS_ID_USER_TCC0_MC_1 #define CONF_COMPARE_TRIGGER TCC0_DMAC_ID_OVF #define CONF_CAPTURE_TRIGGER TCC0_DMAC_ID_MC_1 ● SAM L21 Xplained Pro. #define CONF_PWM_MODULE LED_0_PWM4CTRL_MODULE #define CONF_PWM_CHANNEL LED_0_PWM4CTRL_CHANNEL #define CONF_PWM_OUTPUT LED_0_PWM4CTRL_OUTPUT #define CONF_PWM_OUT_PIN LED_0_PWM4CTRL_PIN #define CONF_PWM_OUT_MUX LED_0_PWM4CTRL_MUX #define CONF_TCC_CAPTURE_CHANNEL 1 #define CONF_TCC_EVENT_GENERATOR EVSYS_ID_GEN_TCC0_MCX_0 #define CONF_TCC_EVENT_USER EVSYS_ID_USER_TCC0_MC_1 #define CONF_COMPARE_TRIGGER TCC0_DMAC_ID_OVF Add to the main application source file, outside of any functions: struct tcc_module tcc_instance; uint16_t capture_values[3] = {0, 0, 0}; struct dma_resource capture_dma_resource; COMPILER_ALIGNED(16) DmacDescriptor capture_dma_descriptor; struct events_resource capture_event_resource; uint16_t compare_values[3] = { (0x1000 / 4), (0x1000 * 2 / 4), (0x1000 * 3 / 4) }; struct dma_resource compare_dma_resource; COMPILER_ALIGNED(16) DmacDescriptor compare_dma_descriptor; Copy-paste the following setup code to your user application: static void config_event_for_capture(void) { struct events_config config; events_get_config_defaults(&config); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 513 config.generator config.edge_detect config.path config.clock_source = = = = CONF_TCC_EVENT_GENERATOR; EVENTS_EDGE_DETECT_RISING; EVENTS_PATH_SYNCHRONOUS; GCLK_GENERATOR_0; events_allocate(&capture_event_resource, &config); } events_attach_user(&capture_event_resource, CONF_TCC_EVENT_USER); static void config_dma_for_capture(void) { struct dma_resource_config config; dma_get_config_defaults(&config); config.trigger_action = DMA_TRIGGER_ACTON_BEAT; config.peripheral_trigger = CONF_CAPTURE_TRIGGER; dma_allocate(&capture_dma_resource, &config); struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.block_transfer_count = 3; descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.step_selection = DMA_STEPSEL_SRC; descriptor_config.src_increment_enable = false; descriptor_config.source_address = (uint32_t)&CONF_PWM_MODULE->CC[CONF_TCC_CAPTURE_CHANNEL]; descriptor_config.destination_address = (uint32_t)capture_values + sizeof(capture_values); dma_descriptor_create(&capture_dma_descriptor, &descriptor_config); } dma_add_descriptor(&capture_dma_resource, &capture_dma_descriptor); dma_add_descriptor(&capture_dma_resource, &capture_dma_descriptor); dma_start_transfer_job(&capture_dma_resource); static void config_dma_for_wave(void) { struct dma_resource_config config; dma_get_config_defaults(&config); config.trigger_action = DMA_TRIGGER_ACTON_BEAT; config.peripheral_trigger = CONF_COMPARE_TRIGGER; dma_allocate(&compare_dma_resource, &config); struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.block_transfer_count = 3; descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.dst_increment_enable = false; descriptor_config.source_address = (uint32_t)compare_values + sizeof(compare_values); descriptor_config.destination_address = AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 514 (uint32_t)&CONF_PWM_MODULE->CC[CONF_PWM_CHANNEL]; dma_descriptor_create(&compare_dma_descriptor, &descriptor_config); } dma_add_descriptor(&compare_dma_resource, &compare_dma_descriptor); dma_add_descriptor(&compare_dma_resource, &compare_dma_descriptor); dma_start_transfer_job(&compare_dma_resource); static void configure_tcc(void) { struct tcc_config config_tcc; tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); config_tcc.counter.period = 0x1000; config_tcc.compare.channel_function[CONF_TCC_CAPTURE_CHANNEL] = TCC_CHANNEL_FUNCTION_CAPTURE; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.wave_polarity[CONF_PWM_CHANNEL] = TCC_WAVE_POLARITY_0; config_tcc.compare.match[CONF_PWM_CHANNEL] = compare_values[2]; config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); struct tcc_events events_tcc = { .input_config[0].modify_action = false, .input_config[1].modify_action = false, .output_config.modify_generation_selection = false, .generate_event_on_channel[CONF_PWM_CHANNEL] = true, .on_event_perform_channel_action[CONF_TCC_CAPTURE_CHANNEL] = true }; tcc_enable_events(&tcc_instance, &events_tcc); config_event_for_capture(); config_dma_for_capture(); config_dma_for_wave(); } tcc_enable(&tcc_instance); Add to user application initialization (typically the start of main()): configure_tcc(); Workflow Configure the TCC 1. Create a module software instance structure for the TCC module to store the TCC driver state while it is in use. struct tcc_module tcc_instance; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 515 Note This should never go out of scope as long as the module is in use. In most cases, this should be global. 2. Create a TCC module configuration struct, which can be filled out to adjust the configuration of a physical TCC peripheral. struct tcc_config config_tcc; 3. Initialize the TCC configuration struct with the module's default values. tcc_get_config_defaults(&config_tcc, CONF_PWM_MODULE); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Alter the TCC settings to configure the counter width, wave generation mode and the compare channel 0 value. config_tcc.counter.period = 0x1000; config_tcc.compare.channel_function[CONF_TCC_CAPTURE_CHANNEL] = TCC_CHANNEL_FUNCTION_CAPTURE; config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM; config_tcc.compare.wave_polarity[CONF_PWM_CHANNEL] = TCC_WAVE_POLARITY_0; config_tcc.compare.match[CONF_PWM_CHANNEL] = compare_values[2]; 5. Alter the TCC settings to configure the PWM output on a physical device pin. config_tcc.pins.enable_wave_out_pin[CONF_PWM_OUTPUT] = true; config_tcc.pins.wave_out_pin[CONF_PWM_OUTPUT] = CONF_PWM_OUT_PIN; config_tcc.pins.wave_out_pin_mux[CONF_PWM_OUTPUT] = CONF_PWM_OUT_MUX; 6. Configure the TCC module with the desired settings. tcc_init(&tcc_instance, CONF_PWM_MODULE, &config_tcc); 7. Configure and enable the desired events for the TCC module. struct tcc_events events_tcc = { .input_config[0].modify_action = false, .input_config[1].modify_action = false, .output_config.modify_generation_selection = false, .generate_event_on_channel[CONF_PWM_CHANNEL] = true, .on_event_perform_channel_action[CONF_TCC_CAPTURE_CHANNEL] = true }; tcc_enable_events(&tcc_instance, &events_tcc); Configure the Event System Configure the EVSYS module to wire channel 0 event to channel 1. 1. Create an event resource instance. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 516 struct events_resource capture_event_resource; Note This should never go out of scope as long as the resource is in use. In most cases, this should be global. 2. Create an event resource configuration struct. struct events_config config; 3. Initialize the event resource configuration struct with default values. events_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Adjust the event resource configuration to desired values. config.generator config.edge_detect config.path config.clock_source 5. = = = = CONF_TCC_EVENT_GENERATOR; EVENTS_EDGE_DETECT_RISING; EVENTS_PATH_SYNCHRONOUS; GCLK_GENERATOR_0; Allocate and configure the resource using the configuration structure. events_allocate(&capture_event_resource, &config); 6. Attach a user to the resource. events_attach_user(&capture_event_resource, CONF_TCC_EVENT_USER); Configure the DMA for Capture TCC Channel 1 Configure the DMAC module to obtain captured value from TCC channel 1. 1. Create a DMA resource instance. struct dma_resource capture_dma_resource; Note This should never go out of scope as long as the resource is in use. In most cases, this should be global. 2. Create a DMA resource configuration struct. struct dma_resource_config config; 3. Initialize the DMA resource configuration struct with default values. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 517 dma_get_config_defaults(&config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 4. Adjust the DMA resource configurations. config.trigger_action = DMA_TRIGGER_ACTON_BEAT; config.peripheral_trigger = CONF_CAPTURE_TRIGGER; 5. Allocate a DMA resource with the configurations. dma_allocate(&capture_dma_resource, &config); 6. Prepare DMA transfer descriptor. a. Create a DMA transfer descriptor. COMPILER_ALIGNED(16) DmacDescriptor capture_dma_descriptor; Note When multiple descriptors are linked, the linked item should never go out of scope before it is loaded (to DMA Write-Back memory section). In most cases, if more than one descriptors are used, they should be global except the very first one. b. Create a DMA transfer descriptor struct. c. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer. struct dma_descriptor_config descriptor_config; d. Initialize the DMA transfer descriptor configuration struct with default values. dma_descriptor_get_config_defaults(&descriptor_config); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. e. Adjust the DMA transfer descriptor configurations. descriptor_config.block_transfer_count = 3; descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.step_selection = DMA_STEPSEL_SRC; descriptor_config.src_increment_enable = false; descriptor_config.source_address = (uint32_t)&CONF_PWM_MODULE->CC[CONF_TCC_CAPTURE_CHANNEL]; descriptor_config.destination_address = (uint32_t)capture_values + sizeof(capture_values); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 518 f. Create the DMA transfer descriptor with the given configuration. dma_descriptor_create(&capture_dma_descriptor, &descriptor_config); 7. Start DMA transfer job with prepared descriptor. a. Add the DMA transfer descriptor to the allocated DMA resource. dma_add_descriptor(&capture_dma_resource, &capture_dma_descriptor); dma_add_descriptor(&capture_dma_resource, &capture_dma_descriptor); Note When adding multiple descriptors, the last added one is linked at the end of descriptor queue. If ringed list is needed, just add the first descriptor again to build the circle. b. Start the DMA transfer job with the allocated DMA resource and transfer descriptor. dma_start_transfer_job(&capture_dma_resource); Configure the DMA for Compare TCC Channel 0 Configure the DMAC module to update TCC channel 0 compare value. The flow is similar to last DMA configure step for capture. 1. Allocate and configure the DMA resource. struct dma_resource compare_dma_resource; struct dma_resource_config config; dma_get_config_defaults(&config); config.trigger_action = DMA_TRIGGER_ACTON_BEAT; config.peripheral_trigger = CONF_COMPARE_TRIGGER; dma_allocate(&compare_dma_resource, &config); 2. Prepare DMA transfer descriptor. COMPILER_ALIGNED(16) DmacDescriptor compare_dma_descriptor; struct dma_descriptor_config descriptor_config; dma_descriptor_get_config_defaults(&descriptor_config); descriptor_config.block_transfer_count = 3; descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD; descriptor_config.dst_increment_enable = false; descriptor_config.source_address = (uint32_t)compare_values + sizeof(compare_values); descriptor_config.destination_address = (uint32_t)&CONF_PWM_MODULE->CC[CONF_PWM_CHANNEL]; dma_descriptor_create(&compare_dma_descriptor, &descriptor_config); 3. Start DMA transfer job with prepared descriptor. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 519 dma_add_descriptor(&compare_dma_resource, &compare_dma_descriptor); dma_add_descriptor(&compare_dma_resource, &compare_dma_descriptor); dma_start_transfer_job(&compare_dma_resource); 4. Enable the TCC module to start the timer and begin PWM signal generation. tcc_enable(&tcc_instance); 21.8.7.2 Use Case Code Copy-paste the following code to your user application: while (true) { /* Infinite loop */ } Workflow 1. Enter an infinite loop while the PWM wave is generated via the TCC module. while (true) { /* Infinite loop */ } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 520 22. SAM Timer/Counter Driver (TC) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the timer modules within the device, for waveform generation and timing operations. The following driver API modes are covered by this manual: ● Polled APIs The following peripherals are used by this module: ● TC (Timer/Counter) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 22.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 22.2 Module Overview The Timer/Counter (TC) module provides a set of timing and counting related functionality, such as the generation of periodic waveforms, the capturing of a periodic waveform's frequency/duty cycle, and software timekeeping for periodic operations. TC modules can be configured to use an 8-, 16-, or 32-bit counter size. This TC module for the SAM is capable of the following functions: ● Generation of PWM signals ● Generation of timestamps for events ● General time counting ● Waveform period capture ● Waveform frequency capture 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 521 Figure 22-1: Basic Overview of the TC Module on page 522 shows the overview of the TC module design. Figure 22-1. Basic Overview of the TC Module Base Counter PERB PER Prescaler "count" "clear" "load" "direction" Counter COUNT = Control Logic TOP BOTTOM =0 "ev" UPDATE BV OVF (INT/Event/DMA Req.) ERR (INT Req.) "TCCx_EV0" "TCCx_EV1" "TCCx_MCx" Event System WO[7] = 22.2.1 Note 22.2.2 Waveform Generation Non-recoverable Faults SWAP Dead-Time Insertion CCx Output Matrix CCBx Control Logic Recoverable Faults BV "capture" Pattern Generation WO[6] Compare/Capture (Unit x = {0,1,…,3}) "match" WO[5] WO[4] WO[3] WO[2] WO[1] WO[0] MCx (INT/Event/DMA Req.) Driver Feature Macro Definition Driver Feature Macro Supported devices FEATURE_TC_DOUBLE_BUFFERED SAML21 FEATURE_TC_SYNCBUSY_SCHEME_VERSION_2 SAML21 FEATURE_TC_STAMP_PW_CAPTURE SAML21 FEATURE_TC_READ_SYNC SAML21 FEATURE_TC_IO_CAPTURE SAML21 The specific features are only available in the driver when the selected device supports those features. Functional Description Independent of the configured counter size, each TC module can be set up in one of two different modes; capture and compare. In capture mode, the counter value is stored when a configurable event occurs. This mode can be used to generate timestamps used in event capture, or it can be used for the measurement of a periodic input signal's frequency/duty cycle. In compare mode, the counter value is compared against one or more of the configured channel compare values. When the counter value coincides with a compare value an action can be taken automatically by the module, such as generating an output event or toggling a pin when used for frequency or PWM signal generation. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 522 Note 22.2.3 The connection of events between modules requires the use of the SAM Event System Driver (EVENTS) to route output event of one module to the the input event of another. For more information on event routing, refer to the event driver documentation. Timer/Counter Size Each timer module can be configured in one of three different counter sizes; 8-, 16-, and 32-bit. The size of the counter determines the maximum value it can count to before an overflow occurs and the count is reset back to zero. Table 22-1: Timer Counter Sizes and Their Maximum Count Values on page 523 shows the maximum values for each of the possible counter sizes. Table 22-1. Timer Counter Sizes and Their Maximum Count Values Counter size Max. (hexadecimal) Max. (decimal) 8-bit 0xFF 255 16-bit 0xFFFF 65,535 32-bit 0xFFFFFFFF 4,294,967,295 When using the counter in 16- or 32-bit count mode, Compare Capture register 0 (CC0) is used to store the period value when running in PWM generation match mode. When using 32-bit counter size, two 16-bit counters are chained together in a cascade formation. Except in SAM D10/D11, Even numbered TC modules (e.g. TC0, TC2) can be configured as 32-bit counters. The odd numbered counters will act as slaves to the even numbered masters, and will not be reconfigurable until the master timer is disabled. The pairing of timer modules for 32-bit mode is shown in Table 22-2: TC Master and Slave Module Pairings on page 523. Table 22-2. TC Master and Slave Module Pairings Master TC Module Slave TC Module TC0 TC1 TC2 TC3 ... ... TCn-1 TCn In SAMD10/D11, odd numbered TC modules (e.g. TC1) can be configured as 32-bit counters. The even numbered(e.g. TC2) counters will act as slaves to the odd numbered masters. 22.2.4 Clock Settings 22.2.4.1 Clock Selection Each TC peripheral is clocked asynchronously to the system clock by a GCLK (Generic Clock) channel. The GCLK channel connects to any of the GCLK generators. The GCLK generators are configured to use one of the available clock sources on the system such as internal oscillator, external crystals, etc. see the Generic Clock driver for more information. 22.2.4.2 Prescaler Each TC module in the SAM has its own individual clock prescaler, which can be used to divide the input clock frequency used in the counter. This prescaler only scales the clock used to provide clock pulses for the counter to count, and does not affect the digital register interface portion of the module, thus the timer registers will synchronize to the raw GCLK frequency input to the module. As a result of this, when selecting a GCLK frequency and timer prescaler value the user application should consider both the timer resolution required and the synchronization frequency, to avoid lengthy synchronization times of the module if a very slow GCLK frequency is fed into the TC module. It is preferable to use a higher module GCLK frequency as the input to the timer, and prescale this down as much as possible to obtain a suitable counter frequency in latency-sensitive applications. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 523 22.2.4.3 Reloading Timer modules also contain a configurable reload action, used when a re-trigger event occurs. Examples of a retrigger event are the counter reaching the maximum value when counting up, or when an event from the event system tells the counter to re-trigger. The reload action determines if the prescaler should be reset, and when this should happen. The counter will always be reloaded with the value it is set to start counting from. The user can choose between three different reload actions, described in Table 22-3: TC Module Reload Actions on page 524. Table 22-3. TC Module Reload Actions Reload action Description TC_RELOAD_ACTION_GCLK on page 543 Reload TC counter value on next GCLK cycle. Leave prescaler as-is. TC_RELOAD_ACTION_PRESC on page 543 Reloads TC counter value on next prescaler clock. Leave prescaler as-is. TC_RELOAD_ACTION_RESYNC on page 543 Reload TC counter value on next GCLK cycle. Clear prescaler to zero. The reload action to use will depend on the specific application being implemented. One example is when an external trigger for a reload occurs; if the TC uses the prescaler, the counter in the prescaler should not have a value between zero and the division factor. The TC counter and the counter in the prescaler should both start at zero. When the counter is set to re-trigger when it reaches the maximum value on the other hand, this is not the right option to use. In such a case it would be better if the prescaler is left unaltered when the re-trigger happens, letting the counter reset on the next GCLK cycle. 22.2.5 Compare Match Operations In compare match operation, Compare/Capture registers are used in comparison with the counter value. When the timer's count value matches the value of a compare channel, a user defined action can be taken. 22.2.5.1 Basic Timer A Basic Timer is a simple application where compare match operations is used to determine when a specific period has elapsed. In Basic Timer operations, one or more values in the module's Compare/Capture registers are used to specify the time (as a number of prescaled GCLK cycles) when an action should be taken by the microcontroller. This can be an Interrupt Service Routine (ISR), event generator via the event system, or a software flag that is polled via the user application. 22.2.5.2 Waveform Generation Waveform generation enables the TC module to generate square waves, or if combined with an external passive low-pass filter; analog waveforms. 22.2.5.3 Waveform Generation - PWM Pulse width modulation is a form of waveform generation and a signalling technique that can be useful in many situations. When PWM mode is used, a digital pulse train with a configurable frequency and duty cycle can be generated by the TC module and output to a GPIO pin of the device. Often PWM is used to communicate a control or information parameter to an external circuit or component. Differing impedances of the source generator and sink receiver circuits is less of an issue when using PWM compared to using an analog voltage value, as noise will not generally affect the signal's integrity to a meaningful extent. Figure 22-2: Example of PWM in Normal Mode, and Different Counter Operations on page 524 illustrates operations and different states of the counter and its output when running the counter in PWM normal mode. As can be seen, the TOP value is unchanged and is set to MAX. The compare match value is changed at several points to illustrate the resulting waveform output changes. The PWM output is set to normal (i.e. non-inverted) output mode. Figure 22-2. Example of PWM in Normal Mode, and Different Counter Operations AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 524 In Figure 22-3: Example of PWM in Match Mode, and Different Counter Operations on page 525, the counter is set to generate PWM in Match mode. The PWM output is inverted via the appropriate configuration option in the TC driver configuration structure. In this example, the counter value is changed once, but the compare match value is kept unchanged. As can be seen, it is possible to change the TOP value when running in PWM match mode. Figure 22-3. Example of PWM in Match Mode, and Different Counter Operations (CC0) (COUNT) (COUNT) Com pare/Mat ch value (CCx) (CC0) 22.2.5.4 Waveform Generation - Frequency Frequency Generation mode is in many ways identical to PWM generation. However, in Frequency Generation a toggle only occurs on the output when a match on a capture channels occurs. When the match is made, the timer value is reset, resulting in a variable frequency square wave with a fixed 50% duty cycle. 22.2.5.5 Capture Operations In capture operations, any event from the event system or a pin change can trigger a capture of the counter value. This captured counter value can be used as a timestamp for the event, or it can be used in frequency and pulse width capture. 22.2.5.6 Capture Operations - Event Event capture is a simple use of the capture functionality, designed to create timestamps for specific events. When the TC module's input capture pin is externally toggled, the current timer count value is copied into a buffered register which can then be read out by the user application. Note that when performing any capture operation, there is a risk that the counter reaches its top value (MAX) when counting up, or the bottom value (zero) when counting down, before the capture event occurs. This can distort the result, making event timestamps to appear shorter than reality; the user application should check for timer overflow when reading a capture result in order to detect this situation and perform an appropriate adjustment. Before checking for a new capture, TC_STATUS_COUNT_OVERFLOW should be checked. The response to an overflow error is left to the user application, however it may be necessary to clear both the capture overflow flag and the capture flag upon each capture reading. 22.2.5.7 Capture Operations - Pulse Width Pulse Width Capture mode makes it possible to measure the pulse width and period of PWM signals. This mode uses two capture channels of the counter. This means that the counter module used for Pulse Width Capture can not be used for any other purpose. There are two modes for pulse width capture; Pulse Width Period (PWP) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 525 and Period Pulse Width (PPW). In PWP mode, capture channel 0 is used for storing the pulse width and capture channel 1 stores the observed period. While in PPW mode, the roles of the two capture channels is reversed. As in the above example it is necessary to poll on interrupt flags to see if a new capture has happened and check that a capture overflow error has not occurred. 22.2.6 One-shot Mode TC modules can be configured into a one-shot mode. When configured in this manner, starting the timer will cause it to count until the next overflow or underflow condition before automatically halting, waiting to be manually triggered by the user application software or an event signal from the event system. 22.2.6.1 Wave Generation Output Inversion The output of the wave generation can be inverted by hardware if desired, resulting in the logically inverted value being output to the configured device GPIO pin. 22.3 Special Considerations The number of capture compare registers in each TC module is dependent on the specific SAM device being used, and in some cases the counter size. The maximum amount of capture compare registers available in any SAM device is two when running in 32-bit mode and four in 8- and 16-bit modes. 22.4 Extra Information For extra information, see Extra Information for TC Driver. This includes: 22.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for TC Driver. 22.6 API Overview 22.6.1 Variable and Type Definitions 22.6.1.1 Type tc_callback_t typedef void(* tc_callback_t )(struct tc_module *const module) 22.6.2 Structure Definitions 22.6.2.1 Struct tc_16bit_config Table 22-4. Members Type Name Description uint16_t compare_capture_channel[] Value to be used for compare match on each channel. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 526 Type Name Description uint16_t value Initial timer count value. Type Name Description uint32_t compare_capture_channel[] Value to be used for compare match on each channel. uint32_t value Initial timer count value. Type Name Description uint8_t compare_capture_channel[] Value to be used for compare match on each channel. uint8_t period Where to count to or from depending on the direction on the counter. uint8_t value Initial timer count value. 22.6.2.2 Struct tc_32bit_config Table 22-5. Members 22.6.2.3 Struct tc_8bit_config Table 22-6. Members 22.6.2.4 Struct tc_config Configuration struct for a TC instance. This structure should be initialized by the tc_get_config_defaults function before being modified by the user application. Table 22-7. Members Type Name Description union tc_config.@3 @3 Access the different counter size settings though this configuration member. enum tc_clock_prescaler clock_prescaler Specifies the prescaler value for GCLK_TC. enum gclk_generator clock_source GCLK generator used to clock the peripheral. enum tc_count_direction count_direction Specifies the direction for the TC to count. enum tc_counter_size counter_size Specifies either 8-, 16-, or 32-bit counter size. bool double_buffering_enabled Set to true to enable double buffering write. When enabled any write through tc_set_top_value(), tc_set_compare_value() and will direct to the buffer register as buffered value, and the buffered value will be committed to effective AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 527 Type Name Description register on UPDATE condition, if update is not locked. bool enable_capture_on_channel[] Specifies which channel(s) to enable channel capture operation on. bool enable_capture_on_IO[] Specifies which channel(s) to enable I/O capture operation on. bool on_demand Run on demand. bool oneshot When true, one-shot will stop the TC on next hardware or software re-trigger event or overflow/ underflow. struct tc_pwm_channel pwm_channel[] Specifies the PWM channel for TC. enum tc_reload_action reload_action Specifies the reload or reset time of the counter and prescaler resynchronization on a re-trigger event for the TC. bool run_in_standby When true the module is enabled during standby. enum tc_wave_generation wave_generation Specifies which waveform generation mode to use. uint8_t waveform_invert_output Specifies which channel(s) to invert the waveform on. For SAML21, it's also used to invert IO input pin. 22.6.2.5 Union tc_config.__unnamed__ Access the different counter size settings though this configuration member. Table 22-8. Members Type Name Description struct tc_16bit_config counter_16_bit Struct for 16-bit specific timer configuration. struct tc_32bit_config counter_32_bit Struct for 32-bit specific timer configuration. struct tc_8bit_config counter_8_bit Struct for 8-bit specific timer configuration. 22.6.2.6 Struct tc_events Event flags for the tc_enable_events() and tc_disable_events(). Table 22-9. Members Type Name Description enum tc_event_action event_action Specifies which event to trigger if an event is triggered. bool generate_event_on_compare_channel[] Generate an output event on a compare channel match. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 528 Type Name Description bool generate_event_on_overflow Generate an output event on counter overflow. bool invert_event_input Specifies if the input event source is inverted, when used in PWP or PPW event action modes. bool on_event_perform_action Perform the configured event action when an incoming event is signalled. 22.6.2.7 Struct tc_module TC software instance structure, used to retain software state information of an associated hardware module instance. Note The fields of this structure should not be altered by the user application; they are reserved for moduleinternal use only. 22.6.2.8 Struct tc_pwm_channel Table 22-10. Members 22.6.3 Type Name Description bool enabled When true, PWM output for the given channel is enabled. uint32_t pin_mux Specifies MUX setting for each output channel pin. uint32_t pin_out Specifies pin output for each channel. Macro Definitions 22.6.3.1 Macro FEATURE_TC_DOUBLE_BUFFERED #define FEATURE_TC_DOUBLE_BUFFERED Define port features set according to different device familyTC double buffered 22.6.3.2 Macro FEATURE_TC_SYNCBUSY_SCHEME_VERSION_2 #define FEATURE_TC_SYNCBUSY_SCHEME_VERSION_2 SYNCBUSY scheme version 2 22.6.3.3 Macro FEATURE_TC_STAMP_PW_CAPTURE #define FEATURE_TC_STAMP_PW_CAPTURE AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 529 TC time stamp capture and pulse width capture 22.6.3.4 Macro FEATURE_TC_READ_SYNC #define FEATURE_TC_READ_SYNC Read synchronization of COUNT 22.6.3.5 Macro FEATURE_TC_IO_CAPTURE #define FEATURE_TC_IO_CAPTURE IO pin edge capture 22.6.3.6 Module Status Flags TC status flags, returned by tc_get_status() and cleared by tc_clear_status(). Macro TC_STATUS_CHANNEL_0_MATCH #define TC_STATUS_CHANNEL_0_MATCH (1UL << 0) Timer channel 0 has matched against its compare value, or has captured a new value. Macro TC_STATUS_CHANNEL_1_MATCH #define TC_STATUS_CHANNEL_1_MATCH (1UL << 1) Timer channel 1 has matched against its compare value, or has captured a new value. Macro TC_STATUS_SYNC_READY #define TC_STATUS_SYNC_READY (1UL << 2) Timer register synchronization has completed, and the synchronized count value may be read. Macro TC_STATUS_CAPTURE_OVERFLOW #define TC_STATUS_CAPTURE_OVERFLOW (1UL << 3) A new value was captured before the previous value was read, resulting in lost data. Macro TC_STATUS_COUNT_OVERFLOW AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 530 #define TC_STATUS_COUNT_OVERFLOW (1UL << 4) The timer count value has overflowed from its maximum value to its minimum when counting upward, or from its minimum value to its maximum when counting downward. Macro TC_STATUS_CHN0_BUFFER_VALID #define TC_STATUS_CHN0_BUFFER_VALID (1UL << 5) Channel 0 compare or capture buffer valid. Macro TC_STATUS_CHN1_BUFFER_VALID #define TC_STATUS_CHN1_BUFFER_VALID (1UL << 6) Channel 1 compare or capture buffer valid. Macro TC_STATUS_PERIOD_BUFFER_VALID #define TC_STATUS_PERIOD_BUFFER_VALID (1UL << 7) Period buffer valid. 22.6.3.7 Macro TC_WAVE_GENERATION_MATCH_FREQ_MODE #define TC_WAVE_GENERATION_MATCH_FREQ_MODE TC_WAVE_WAVEGEN_MFRQ 22.6.3.8 Macro TC_WAVE_GENERATION_MATCH_PWM_MODE #define TC_WAVE_GENERATION_MATCH_PWM_MODE TC_WAVE_WAVEGEN_MPWM 22.6.3.9 Macro TC_WAVE_GENERATION_NORMAL_FREQ_MODE #define TC_WAVE_GENERATION_NORMAL_FREQ_MODE TC_WAVE_WAVEGEN_NFRQ TC wave generation mode. 22.6.3.10 Macro TC_WAVE_GENERATION_NORMAL_PWM_MODE #define TC_WAVE_GENERATION_NORMAL_PWM_MODE TC_WAVE_WAVEGEN_NPWM AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 531 22.6.3.11 Macro TC_WAVEFORM_INVERT_CC0_MODE #define TC_WAVEFORM_INVERT_CC0_MODE TC_DRVCTRL_INVEN(1) Waveform inversion mode. 22.6.3.12 Macro TC_WAVEFORM_INVERT_CC1_MODE #define TC_WAVEFORM_INVERT_CC1_MODE TC_DRVCTRL_INVEN(2) 22.6.4 Function Definitions 22.6.4.1 Driver Initialization and Configuration Function tc_is_syncing() Determines if the hardware module(s) are currently synchronizing to the bus. bool tc_is_syncing( const struct tc_module *const module_inst) Checks to see if the underlying hardware peripheral module(s) are currently synchronizing across multiple clock domains to the hardware bus. This function can be used to delay further operations on a module until such time that it is ready, to prevent blocking delays for synchronization in the user application. Table 22-11. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Returns Synchronization status of the underlying hardware module(s). Table 22-12. Return Values Return value Description false If the module has completed synchronization true If the module synchronization is ongoing Function tc_get_config_defaults() Initializes config with predefined default values. void tc_get_config_defaults( struct tc_config *const config) This function will initialize a given TC configuration structure to a set of known default values. This function should be called on any new instance of the configuration structures before being modified by the user application. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 532 The default configuration is as follows: ● GCLK generator 0 (GCLK main) clock source ● 16-bit counter size on the counter ● No prescaler ● Normal frequency wave generation ● GCLK reload action ● Don't run in standby ● Don't run on demand for SAML21 ● No inversion of waveform output ● No capture enabled ● No I/O capture enabled for SAML21 ● No event input enabled ● Count upward ● Don't perform one-shot operations ● No event action ● No channel 0 PWM output ● No channel 1 PWM output ● Counter starts on 0 ● Capture compare channel 0 set to 0 ● Capture compare channel 1 set to 0 ● No PWM pin output enabled ● Pin and MUX configuration not set ● Double buffer disabled (if have this feature) Table 22-13. Parameters Data direction Parameter name Description [out] config Pointer to a TC module configuration structure to set Function tc_init() Initializes a hardware TC module instance. enum status_code tc_init( struct tc_module *const module_inst, Tc *const hw, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 533 const struct tc_config *const config) Enables the clock and initializes the TC module, based on the given configuration values. Table 22-14. Parameters Data direction Parameter name Description [in, out] module_inst Pointer to the software module instance struct [in] hw Pointer to the TC hardware module [in] config Pointer to the TC configuration options struct Returns Status of the initialization procedure. Table 22-15. Return Values Return value Description STATUS_OK The module was initialized successfully STATUS_BUSY Hardware module was busy when the initialization procedure was attempted STATUS_INVALID_ARG An invalid configuration option or argument was supplied STATUS_ERR_DENIED Hardware module was already enabled, or the hardware module is configured in 32-bit slave mode 22.6.4.2 Event Management Function tc_enable_events() Enables a TC module event input or output. void tc_enable_events( struct tc_module *const module_inst, struct tc_events *const events) Enables one or more input or output events to or from the TC module. See tc_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 22-16. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] events Struct containing flags of events to enable AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 534 Function tc_disable_events() Disables a TC module event input or output. void tc_disable_events( struct tc_module *const module_inst, struct tc_events *const events) Disables one or more input or output events to or from the TC module. See tc_events for a list of events this module supports. Note Events cannot be altered while the module is enabled. Table 22-17. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] events Struct containing flags of events to disable 22.6.4.3 Enable/Disable/Reset Function tc_reset() Resets the TC module. enum status_code tc_reset( const struct tc_module *const module_inst) Resets the TC module, restoring all hardware module registers to their default values and disabling the module. The TC module will not be accessible while the reset is being performed. Note When resetting a 32-bit counter only the master TC module's instance structure should be passed to the function. Table 22-18. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Status of the procedure. Table 22-19. Return Values Return value Description STATUS_OK The module was reset successfully STATUS_ERR_UNSUPPORTED_DEV A 32-bit slave TC module was passed to the function. Only use reset on master TC. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 535 Function tc_enable() Enable the TC module. void tc_enable( const struct tc_module *const module_inst) Enables a TC module that has been previously initialized. The counter will start when the counter is enabled. Note When the counter is configured to re-trigger on an event, the counter will not start until the start function is used. Table 22-20. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Function tc_disable() Disables the TC module. void tc_disable( const struct tc_module *const module_inst) Disables a TC module and stops the counter. Table 22-21. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 22.6.4.4 Get/Set Count Value Function tc_get_count_value() Get TC module count value. uint32_t tc_get_count_value( const struct tc_module *const module_inst) Retrieves the current count value of a TC module. The specified TC module may be started or stopped. Table 22-22. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 536 Returns Count value of the specified TC module. Function tc_set_count_value() Sets TC module count value. enum status_code tc_set_count_value( const struct tc_module *const module_inst, const uint32_t count) Sets the current timer count value of a initialized TC module. The specified TC module may be started or stopped. Table 22-23. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] count New timer count value to set Returns Status of the count update procedure. Table 22-24. Return Values Return value Description STATUS_OK The timer count was updated successfully STATUS_ERR_INVALID_ARG An invalid timer counter size was specified 22.6.4.5 Start/Stop Counter Function tc_stop_counter() Stops the counter. void tc_stop_counter( const struct tc_module *const module_inst) This function will stop the counter. When the counter is stopped the value in the count value is set to 0 if the counter was counting up, or maximum if the counter was counting down when stopped. Table 22-25. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct Function tc_start_counter() Starts the counter. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 537 void tc_start_counter( const struct tc_module *const module_inst) Starts or restarts an initialized TC module's counter. Table 22-26. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 22.6.4.6 Double Buffering Function tc_update_double_buffer() Update double buffer. void tc_update_double_buffer( const struct tc_module *const module_inst) Update double buffer. Table 22-27. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 22.6.4.7 Count Read Synchronization Function tc_sync_read_count() Read synchronization of COUNT. void tc_sync_read_count( const struct tc_module *const module_inst) Read synchronization of COUNT. Table 22-28. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct 22.6.4.8 Get Capture Set Compare Function tc_get_capture_value() Gets the TC module capture value. uint32_t tc_get_capture_value( const struct tc_module *const module_inst, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 538 const enum tc_compare_capture_channel channel_index) Retrieves the capture value in the indicated TC module capture channel. Table 22-29. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] channel_index Index of the Compare Capture channel to read Returns Capture value stored in the specified timer channel. Function tc_set_compare_value() Sets a TC module compare value. enum status_code tc_set_compare_value( const struct tc_module *const module_inst, const enum tc_compare_capture_channel channel_index, const uint32_t compare_value) Writes a compare value to the given TC module compare/capture channel. Table 22-30. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] channel_index Index of the compare channel to write to [in] compare New compare value to set Status of the compare update procedure. Table 22-31. Return Values Return value Description STATUS_OK The compare value was updated successfully STATUS_ERR_INVALID_ARG An invalid channel index was supplied 22.6.4.9 Set Top Value Function tc_set_top_value() Set the timer TOP/period value. enum status_code tc_set_top_value( const struct tc_module *const module_inst, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 539 const uint32_t top_value) For 8-bit counter size this function writes the top value to the period register. For 16- and 32-bit counter size this function writes the top value to Capture Compare register 0. The value in this register can not be used for any other purpose. Note This function is designed to be used in PWM or frequency match modes only. When the counter is set to 16- or 32-bit counter size. In 8-bit counter size it will always be possible to change the top value even in normal mode. Table 22-32. Parameters Data direction Parameter name Description [in] module_inst Pointer to the software module instance struct [in] top_value New timer TOP value to set Returns Status of the TOP set procedure. Table 22-33. Return Values Return value Description STATUS_OK The timer TOP value was updated successfully STATUS_ERR_INVALID_ARG The configured TC module counter size in the module instance is invalid. 22.6.4.10 Status Management Function tc_get_status() Retrieves the current module status. uint32_t tc_get_status( struct tc_module *const module_inst) Retrieves the status of the module, giving overall state information. Table 22-34. Parameters Returns Data direction Parameter name Description [in] module_inst Pointer to the TC software instance struct Bitmask of TC_STATUS_* flags. Table 22-35. Return Values Return value Description TC_STATUS_CHANNEL_0_MATCH Timer channel 0 compare/capture match TC_STATUS_CHANNEL_1_MATCH Timer channel 1 compare/capture match AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 540 Return value Description TC_STATUS_SYNC_READY Timer read synchronization has completed TC_STATUS_CAPTURE_OVERFLOW Timer capture data has overflowed TC_STATUS_COUNT_OVERFLOW Timer count value has overflowed TC_STATUS_CHN0_BUFFER_VALID Timer count channel 0 compare/capture buffer valid TC_STATUS_CHN1_BUFFER_VALID Timer count channel 1 compare/capture buffer valid TC_STATUS_PERIOD_BUFFER_VALID Timer count period buffer valid Function tc_clear_status() Clears a module status flag. void tc_clear_status( struct tc_module *const module_inst, const uint32_t status_flags) Clears the given status flag of the module. Table 22-36. Parameters 22.6.5 Data direction Parameter name Description [in] module_inst Pointer to the TC software instance struct [in] status_flags Bitmask of TC_STATUS_* flags to clear Enumeration Definitions 22.6.5.1 Enum tc_callback Enum for the possible callback types for the TC module. Table 22-37. Members Enum value Description TC_CALLBACK_OVERFLOW Callback for TC overflow. TC_CALLBACK_ERROR Callback for capture overflow error. TC_CALLBACK_CC_CHANNEL0 Callback for capture compare channel 0. TC_CALLBACK_CC_CHANNEL1 Callback for capture compare channel 1. 22.6.5.2 Enum tc_clock_prescaler This enum is used to choose the clock prescaler configuration. The prescaler divides the clock frequency of the TC module to make the counter count slower. Table 22-38. Members Enum value Description TC_CLOCK_PRESCALER_DIV1 Divide clock by 1. TC_CLOCK_PRESCALER_DIV2 Divide clock by 2. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 541 Enum value Description TC_CLOCK_PRESCALER_DIV4 Divide clock by 4. TC_CLOCK_PRESCALER_DIV8 Divide clock by 8. TC_CLOCK_PRESCALER_DIV16 Divide clock by 16. TC_CLOCK_PRESCALER_DIV64 Divide clock by 64. TC_CLOCK_PRESCALER_DIV256 Divide clock by 256. TC_CLOCK_PRESCALER_DIV1024 Divide clock by 1024. 22.6.5.3 Enum tc_compare_capture_channel This enum is used to specify which capture/compare channel to do operations on. Table 22-39. Members Enum value Description TC_COMPARE_CAPTURE_CHANNEL_0 Index of compare capture channel 0. TC_COMPARE_CAPTURE_CHANNEL_1 Index of compare capture channel 1. 22.6.5.4 Enum tc_count_direction Timer/Counter count direction. Table 22-40. Members Enum value Description TC_COUNT_DIRECTION_UP Timer should count upward from zero to MAX. TC_COUNT_DIRECTION_DOWN Timer should count downward to zero from MAX. 22.6.5.5 Enum tc_counter_size This enum specifies the maximum value it is possible to count to. Table 22-41. Members Enum value Description TC_COUNTER_SIZE_8BIT The counter's maximum value is 0xFF, the period register is available to be used as top value. TC_COUNTER_SIZE_16BIT The counter's maximum value is 0xFFFF. There is no separate period register, to modify top one of the capture compare registers has to be used. This limits the amount of available channels. TC_COUNTER_SIZE_32BIT The counter's maximum value is 0xFFFFFFFF. There is no separate period register, to modify top one of the capture compare registers has to be used. This limits the amount of available channels. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 542 22.6.5.6 Enum tc_event_action Event action to perform when the module is triggered by an event. Table 22-42. Members Enum value Description TC_EVENT_ACTION_OFF No event action. TC_EVENT_ACTION_RETRIGGER Re-trigger on event. TC_EVENT_ACTION_INCREMENT_COUNTER Increment counter on event. TC_EVENT_ACTION_START Start counter on event. TC_EVENT_ACTION_PPW Store period in capture register 0, pulse width in capture register 1. TC_EVENT_ACTION_PWP Store pulse width in capture register 0, period in capture register 1. TC_EVENT_ACTION_STAMP Time stamp capture. TC_EVENT_ACTION_PW Pulse width capture. 22.6.5.7 Enum tc_reload_action This enum specify how the counter and prescaler should reload. Table 22-43. Members Enum value Description TC_RELOAD_ACTION_GCLK The counter is reloaded/reset on the next GCLK and starts counting on the prescaler clock. TC_RELOAD_ACTION_PRESC The counter is reloaded/reset on the next prescaler clock. TC_RELOAD_ACTION_RESYNC The counter is reloaded/reset on the next GCLK, and the prescaler is restarted as well. 22.6.5.8 Enum tc_wave_generation This enum is used to select which mode to run the wave generation in. Table 22-44. Members Enum value Description TC_WAVE_GENERATION_NORMAL_FREQ Top is maximum, except in 8-bit counter size where it is the PER register. TC_WAVE_GENERATION_MATCH_FREQ Top is CC0, except in 8-bit counter size where it is the PER register. TC_WAVE_GENERATION_NORMAL_PWM Top is maximum, except in 8-bit counter size where it is the PER register. TC_WAVE_GENERATION_MATCH_PWM Top is CC0, except in 8-bit counter size where it is the PER register. 22.6.5.9 Enum tc_waveform_invert_output Output waveform inversion mode. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 543 Table 22-45. Members Enum value Description TC_WAVEFORM_INVERT_OUTPUT_NONE No inversion of the waveform output. TC_WAVEFORM_INVERT_OUTPUT_CHANNEL_0 Invert output from compare channel 0. TC_WAVEFORM_INVERT_OUTPUT_CHANNEL_1 Invert output from compare channel 1. 22.7 Extra Information for TC Driver 22.7.1 Acronyms The table below presents the acronyms used in this module: 22.7.2 Acronym Description DMA Direct Memory Access TC Timer Counter PWM Pulse Width Modulation PWP Pulse Width Period PPW Period Pulse Width Dependencies This driver has the following dependencies: ● 22.7.3 System Pin Multiplexer Driver Errata There are no errata related to this driver. 22.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Added support for SAML21 Added support for SAMD10/D11 Added support for SAMR21 Added support for SAMD21 and do some modifications as below: ● Clean up in the configuration structure, the counter size setting specific registers is accessed through the counter_8_bit, counter_16_bit and counter_32_bit structures ● All event related settings moved into the tc_event structure Added automatic digital clock interface enable for the slave TC module when a timer is initialized in 32-bit mode Initial Release 22.8 Examples for TC Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Timer/Counter Driver (TC). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 544 ● asfdoc_sam0_tc_basic_use_case ● asfdoc_sam0_tc_dma_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 545 23. SAM Watchdog Driver (WDT) 1 Support and FAQ: visit Atmel Support This driver for Atmel# | SMART SAM devices provides an interface for the configuration and management of the device's Watchdog Timer module, including the enabling, disabling, and kicking within the device. The following driver API modes are covered by this manual: ● Polled APIs ● Callback APIs The following peripherals are used by this module: ● WDT (Watchdog Timer) The following devices can use this module: ● Atmel | SMART SAM D20/D21 ● Atmel | SMART SAM R21 ● Atmel | SMART SAM D10/D11 ● Atmel | SMART SAM L21 The outline of this documentation is as follows: 23.1 ● Prerequisites ● Module Overview ● Special Considerations ● Extra Information ● Examples ● API Overview Prerequisites There are no prerequisites for this module. 23.2 Module Overview The Watchdog module (WDT) is designed to give an added level of safety in critical systems, to ensure a system reset is triggered in the case of a deadlock or other software malfunction that prevents normal device operation. At a basic level, the Watchdog is a system timer with a fixed period; once enabled, it will continue to count ticks of its asynchronous clock until it is periodically reset, or the timeout period is reached. In the event of a Watchdog timeout, the module will trigger a system reset identical to a pulse of the device's reset pin, resetting all peripherals to their power-on default states and restarting the application software from the reset vector. In many systems, there is an obvious upper bound to the amount of time each iteration of the main application loop can be expected to run, before a malfunction can be assumed (either due to a deadlock waiting on hardware or software, or due to other means). When the Watchdog is configured with a timeout period equal to this upper bound, a malfunction in the system will force a full system reset to allow for a graceful recovery. 1 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 546 23.2.1 Locked Mode The Watchdog configuration can be set in the device fuses and locked in hardware, so that no software changes can be made to the Watchdog configuration. Additionally, the Watchdog can be locked on in software if it is not already locked, so that the module configuration cannot be modified until a power on reset of the device. The locked configuration can be used to ensure that faulty software does not cause the Watchdog configuration to be changed, preserving the level of safety given by the module. 23.2.2 Window Mode Just as there is a reasonable upper bound to the time the main program loop should take for each iteration, there is also in many applications a lower bound, i.e. a minimum time for which each loop iteration should run for under normal circumstances. To guard against a system failure resetting the Watchdog in a tight loop (or a failure in the system application causing the main loop to run faster than expected) a "Window" mode can be enabled to disallow resetting of the Watchdog counter before a certain period of time. If the Watchdog is not reset after the window opens but not before the Watchdog expires, the system will reset. 23.2.3 Early Warning In some cases it is desirable to receive an early warning that the Watchdog is about to expire, so that some system action (such as saving any system configuration data for failure analysis purposes) can be performed before the system reset occurs. The Early Warning feature of the Watchdog module allows such a notification to be requested; after the configured early warning time (but before the expiry of the Watchdog counter) the Early Warning flag will become set, so that the user application can take an appropriate action. Note 23.2.4 It is important to note that the purpose of the Early Warning feature is not to allow the user application to reset the Watchdog; doing so will defeat the safety the module gives to the user application. Instead, this feature should be used purely to perform any tasks that need to be undertaken before the system reset occurs. Physical Connection Figure 23-1: Physical Connection on page 547 shows how this module is interconnected within the device. Figure 23-1. Physical Connection WDT GCLK* Ge n e r ic Clo c k Note 23.3 Wa t c h d o g Co u n t e r S ys t e m Re s e t Lo g ic SAM L21's Watchdog Counter is not provided by GCLK, but it uses an internal 1KHz OSCULP32K output clock. This clock must be configured and enabled in the 32KHz Oscillator Controller(OSC32KCTRL) before using the WDT. Special Considerations On some devices the Watchdog configuration can be fused to be always on in a particular configuration; if this mode is enabled the Watchdog is not software configurable and can have its count reset and early warning state checked/cleared only. 23.4 Extra Information For extra information, see Extra Information for WDT Driver. This includes: AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 547 23.5 ● Acronyms ● Dependencies ● Errata ● Module History Examples For a list of examples related to this driver, see Examples for WDT Driver. 23.6 API Overview 23.6.1 Variable and Type Definitions 23.6.1.1 Callback Configuration and Initialization Type wdt_callback_t typedef void(* wdt_callback_t )(void) Type definition for a WDT module callback function. 23.6.2 Structure Definitions 23.6.2.1 Struct wdt_conf Configuration structure for a Watchdog Timer instance. This structure should be initialized by the wdt_get_config_defaults() function before being modified by the user application. Table 23-1. Members 23.6.3 Type Name Description bool always_on If true, the Watchdog will be locked to the current configuration settings when the Watchdog is enabled. enum wdt_period early_warning_period Number of Watchdog timer clock ticks until the early warning flag is set. bool enable Enable/Disable the Watchdog Timer. enum wdt_period timeout_period Number of Watchdog timer clock ticks until the Watchdog expires. enum wdt_period window_period Number of Watchdog timer clock ticks until the reset window opens. Function Definitions 23.6.3.1 Configuration and Initialization Function wdt_is_syncing() AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 548 Determines if the hardware module(s) are currently synchronizing to the bus. bool wdt_is_syncing(void) Checks to see if the underlying hardware peripheral module(s) are currently synchronizing across multiple clock domains to the hardware bus. This function can be used to delay further operations on a module until such time that it is ready, to prevent blocking delays for synchronization in the user application. Returns Synchronization status of the underlying hardware module(s). Table 23-2. Return Values Return value Description true If the module has completed synchronization false If the module synchronization is ongoing Function wdt_get_config_defaults() Initializes a Watchdog Timer configuration structure to defaults. void wdt_get_config_defaults( struct wdt_conf *const config) Initializes a given Watchdog Timer configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application. The default configuration is as follows: ● Not locked, to allow for further (re-)configuration ● Enable WDT ● Watchdog timer sourced from Generic Clock Channel 4 ● A timeout period of 16384 clocks of the Watchdog module clock ● No window period, so that the Watchdog count can be reset at any time ● No early warning period to indicate the Watchdog will soon expire Table 23-3. Parameters Data direction Parameter name Description [out] config Configuration structure to initialize to default values Function wdt_set_config() Sets up the WDT hardware module based on the configuration. enum status_code wdt_set_config( const struct wdt_conf *const config) AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 549 2 Support and FAQ: visit Atmel Support Writes a given configuration of a WDT configuration to the hardware module, and initializes the internal device struct. Table 23-4. Parameters Returns Data direction Parameter name Description [in] config Pointer to the configuration struct Status of the configuration procedure. Table 23-5. Return Values Return value Description STATUS_OK If the module was configured correctly STATUS_ERR_INVALID_ARG If invalid argument(s) were supplied STATUS_ERR_IO If the Watchdog module is locked to be always on Function wdt_is_locked() Determines if the Watchdog timer is currently locked in an enabled state. bool wdt_is_locked(void) Determines if the Watchdog timer is currently enabled and locked, so that it cannot be disabled or otherwise reconfigured. Returns Current Watchdog lock state. 23.6.3.2 Timeout and Early Warning Management Function wdt_clear_early_warning() Clears the Watchdog timer early warning period elapsed flag. void wdt_clear_early_warning(void) Clears the Watchdog timer early warning period elapsed flag, so that a new early warning period can be detected. Function wdt_is_early_warning() Determines if the Watchdog timer early warning period has elapsed. bool wdt_is_early_warning(void) Determines if the Watchdog timer early warning period has elapsed. 2 http://www.atmel.com/design-support/ AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 550 Note If no early warning period was configured, the value returned by this function is invalid. Returns Current Watchdog Early Warning state. Function wdt_reset_count() Resets the count of the running Watchdog Timer that was previously enabled. void wdt_reset_count(void) Resets the current count of the Watchdog Timer, restarting the timeout period count elapsed. This function should be called after the window period (if one was set in the module configuration) but before the timeout period to prevent a reset of the system. 23.6.3.3 Callback Configuration and Initialization Function wdt_register_callback() Registers an asynchronous callback function with the driver. enum status_code wdt_register_callback( const wdt_callback_t callback, const enum wdt_callback type) Registers an asynchronous callback with the WDT driver, fired when a given criteria (such as an Early Warning) is met. Callbacks are fired once for each event. Table 23-6. Parameters Returns Data direction Parameter name Description [in] callback Pointer to the callback function to register [in] type Type of callback function to register Status of the registration operation. Table 23-7. Return Values Return value Description STATUS_OK The callback was registered successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied Function wdt_unregister_callback() Unregisters an asynchronous callback function with the driver. enum status_code wdt_unregister_callback( AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 551 const enum wdt_callback type) Unregisters an asynchronous callback with the WDT driver, removing it from the internal callback registration table. Table 23-8. Parameters Data direction Parameter name Description [in] type Type of callback function to unregister Returns Status of the de-registration operation. Table 23-9. Return Values Return value Description STATUS_OK The callback was Unregistered successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied 23.6.3.4 Callback Enabling and Disabling Function wdt_enable_callback() Enables asynchronous callback generation for a given type. enum status_code wdt_enable_callback( const enum wdt_callback type) Enables asynchronous callbacks for a given callback type. This must be called before an external interrupt channel will generate callback events. Table 23-10. Parameters Returns Data direction Parameter name Description [in] type Type of callback function to enable Status of the callback enable operation. Table 23-11. Return Values Return value Description STATUS_OK The callback was enabled successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied Function wdt_disable_callback() Disables asynchronous callback generation for a given type. enum status_code wdt_disable_callback( const enum wdt_callback type) Disables asynchronous callbacks for a given callback type. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 552 Table 23-12. Parameters Returns Data direction Parameter name Description [in] type Type of callback function to disable Status of the callback disable operation. Table 23-13. Return Values 23.6.4 Return value Description STATUS_OK The callback was disabled successfully STATUS_ERR_INVALID_ARG If an invalid callback type was supplied Enumeration Definitions 23.6.4.1 Callback Configuration and Initialization Enum wdt_callback Enum for the possible callback types for the WDT module. Table 23-14. Members Enum value Description WDT_CALLBACK_EARLY_WARNING Callback type for when an early warning callback from the WDT module is issued. 23.6.4.2 Enum wdt_period Enum for the possible period settings of the Watchdog timer module, for values requiring a period as a number of Watchdog timer clock ticks. Table 23-15. Members Enum value Description WDT_PERIOD_NONE No Watchdog period. This value can only be used when setting the Window and Early Warning periods; its use as the Watchdog Reset Period is invalid. WDT_PERIOD_8CLK Watchdog period of 8 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_16CLK Watchdog period of 16 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_32CLK Watchdog period of 32 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_64CLK Watchdog period of 64 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_128CLK Watchdog period of 128 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_256CLK Watchdog period of 256 clocks of the Watchdog Timer Generic Clock. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 553 Enum value Description WDT_PERIOD_512CLK Watchdog period of 512 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_1024CLK Watchdog period of 1024 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_2048CLK Watchdog period of 2048 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_4096CLK Watchdog period of 4096 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_8192CLK Watchdog period of 8192 clocks of the Watchdog Timer Generic Clock. WDT_PERIOD_16384CLK Watchdog period of 16384 clocks of the Watchdog Timer Generic Clock. 23.7 Extra Information for WDT Driver 23.7.1 Acronyms The table below presents the acronyms used in this module: 23.7.2 Acronym Description WDT Watchdog Timer Dependencies This driver has the following dependencies: ● 23.7.3 System Clock Driver Errata There are no errata related to this driver. 23.7.4 Module History An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table. Changelog Add support for SAML21 Add SAMD21 support and driver updated to follow driver type convention: ● wdt_init, wdt_enable, wdt_disable functions removed ● wdt_set_config function added ● WDT module enable state moved inside the configuration struct Initial Release 23.8 Examples for WDT Driver This is a list of the available Quick Start guides (QSGs) and example applications for SAM Watchdog Driver (WDT). QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 554 23.8.1 ● Quick Start Guide for WDT - Basic ● Quick Start Guide for WDT - Callback Quick Start Guide for WDT - Basic In this use case, the Watchdog module is configured for: ● System reset after 2048 clocks of the Watchdog generic clock ● Always on mode disabled ● Basic mode, with no window or early warning periods This use case sets up the Watchdog to force a system reset after every 2048 clocks of the Watchdog's Generic Clock channel, unless the user periodically resets the Watchdog counter via a button before the timer expires. If the Watchdog resets the device, a LED on the board is turned off. 23.8.1.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void configure_wdt(void) { /* Create a new configuration structure for the Watchdog settings and fill * with the default module settings. */ struct wdt_conf config_wdt; wdt_get_config_defaults(&config_wdt); /* Set the Watchdog configuration settings */ config_wdt.always_on = false; #if !(SAML21) config_wdt.clock_source = GCLK_GENERATOR_4; #endif config_wdt.timeout_period = WDT_PERIOD_2048CLK; } /* Initialize and enable the Watchdog with the user settings */ wdt_set_config(&config_wdt); Add to user application initialization (typically the start of main()): configure_wdt(); Workflow 1. Create a Watchdog module configuration struct, which can be filled out to adjust the configuration of the Watchdog. struct wdt_conf config_wdt; 2. Initialize the Watchdog configuration struct with the module's default values. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 555 wdt_get_config_defaults(&config_wdt); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. 3. Adjust the configuration struct to set the timeout period and lock mode of the Watchdog. config_wdt.always_on = false; #if !(SAML21) config_wdt.clock_source = GCLK_GENERATOR_4; #endif config_wdt.timeout_period = WDT_PERIOD_2048CLK; 4. Setups the WDT hardware module with the requested settings. wdt_set_config(&config_wdt); 23.8.1.2 Quick Start Guide for WDT - Basic Code Copy-paste the following code to your user application: enum system_reset_cause reset_cause = system_get_reset_cause(); if (reset_cause == SYSTEM_RESET_CAUSE_WDT) { port_pin_set_output_level(LED_0_PIN, LED_0_INACTIVE); } else { port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE); } while (true) { if (port_pin_get_input_level(BUTTON_0_PIN) == false) { port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE); } } wdt_reset_count(); Workflow 1. Retrieve the cause of the system reset to determine if the Watchdog module was the cause of the last reset. enum system_reset_cause reset_cause = system_get_reset_cause(); 2. Turn on or off the board LED based on whether the Watchdog reset the device. if (reset_cause == SYSTEM_RESET_CAUSE_WDT) { port_pin_set_output_level(LED_0_PIN, LED_0_INACTIVE); } else { port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE); AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 556 } 3. Enter an infinite loop to hold the main program logic. while (true) { 4. Test to see if the board button is currently being pressed. if (port_pin_get_input_level(BUTTON_0_PIN) == false) { 5. If the button is pressed, turn on the board LED and reset the Watchdog timer. port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE); wdt_reset_count(); 23.8.2 Quick Start Guide for WDT - Callback In this use case, the Watchdog module is configured for: ● System reset after 4096 clocks of the Watchdog generic clock ● Always on mode disabled ● Early warning period of 2048 clocks of the Watchdog generic clock This use case sets up the Watchdog to force a system reset after every 4096 clocks of the Watchdog's Generic Clock channel, with an Early Warning callback being generated every 2048 clocks. Each time the Early Warning interrupt fires the board LED is turned on, and each time the device resets the board LED is turned off, giving a periodic flashing pattern. 23.8.2.1 Setup Prerequisites There are no special setup requirements for this use-case. Code Copy-paste the following setup code to your user application: void watchdog_early_warning_callback(void) { port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE); } void configure_wdt(void) { /* Create a new configuration structure for the Watchdog settings and fill * with the default module settings. */ struct wdt_conf config_wdt; wdt_get_config_defaults(&config_wdt); /* Set the Watchdog configuration config_wdt.always_on = #if !(SAML21) config_wdt.clock_source = #endif config_wdt.timeout_period = settings */ false; GCLK_GENERATOR_4; WDT_PERIOD_4096CLK; AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 557 config_wdt.early_warning_period = WDT_PERIOD_2048CLK; /* Initialize and enable the Watchdog with the user settings */ wdt_set_config(&config_wdt); } void configure_wdt_callbacks(void) { wdt_register_callback(watchdog_early_warning_callback, WDT_CALLBACK_EARLY_WARNING); wdt_enable_callback(WDT_CALLBACK_EARLY_WARNING); } Add to user application initialization (typically the start of main()): configure_wdt(); configure_wdt_callbacks(); Workflow 1. Configure and enable the Watchdog driver. a. Create a Watchdog module configuration struct, which can be filled out to adjust the configuration of the Watchdog. struct wdt_conf config_wdt; b. Initialize the Watchdog configuration struct with the module's default values. wdt_get_config_defaults(&config_wdt); Note This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings. c. Adjust the configuration struct to set the timeout and early warning periods of the Watchdog. config_wdt.always_on = false; #if !(SAML21) config_wdt.clock_source = GCLK_GENERATOR_4; #endif config_wdt.timeout_period = WDT_PERIOD_4096CLK; config_wdt.early_warning_period = WDT_PERIOD_2048CLK; d. Sets up the WDT hardware module with the requested settings. wdt_set_config(&config_wdt); 2. Register and enable the Early Warning callback handler. a. Register the user-provided Early Warning callback function with the driver, so that it will be run when an Early Warning condition occurs. wdt_register_callback(watchdog_early_warning_callback, AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 558 WDT_CALLBACK_EARLY_WARNING); b. Enable the Early Warning callback so that it will generate callbacks. wdt_enable_callback(WDT_CALLBACK_EARLY_WARNING); 23.8.2.2 Quick Start Guide for WDT - Callback Code Copy-paste the following code to your user application: port_pin_set_output_level(LED_0_PIN, LED_0_INACTIVE); system_interrupt_enable_global(); while (true) { /* Wait for callback */ } Workflow 1. Turn off the board LED when the application starts. port_pin_set_output_level(LED_0_PIN, LED_0_INACTIVE); 2. Enable global interrupts so that callbacks can be generated. system_interrupt_enable_global(); 3. Enter an infinite loop to hold the main program logic. while (true) { /* Wait for callback */ } AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 559 24. Examples for Power Driver This is a list of the available Quick Start Guides (QSGs) and example applications. QSGs are simple examples with step-by-step instructions to configure and use this driver in a selection of use cases. Note that QSGs can be compiled as a standalone application or be added to the user application. ● asfdoc_sam0_power_basic_use_case AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 560 Index E Enumeration Definitions ac_callback, 29 ac_chan_channel, 29 ac_chan_filter, 29 ac_chan_interrupt_selection, 29 ac_chan_neg_mux, 30 ac_chan_output, 30 ac_chan_pos_mux, 31 ac_chan_sample_mode, 31 ac_win_channel, 31 ac_win_interrupt_selection, 31 adc_accumulate_samples, 51 adc_clock_prescaler, 52 adc_divide_result, 52 adc_event_action, 53 adc_gain_factor, 53 adc_interrupt_flag, 53 adc_job_type, 53 adc_negative_input, 53 adc_oversampling_and_decimation, 54 adc_positive_input, 54 adc_reference, 55 adc_resolution, 55 adc_window_mode, 56 bod, 62 bod_action, 62 bod_mode, 62 bod_prescale, 62 dac_callback, 82 dac_channel, 82 dac_output, 82 dac_reference, 83 dma_address_increment_stepsize, 106 dma_beat_size, 106 dma_block_action, 107 dma_callback_type, 107 dma_event_input_action, 107 dma_event_output_selection, 108 dma_priority_level, 108 dma_step_selection, 108 dma_transfer_trigger_action, 108 events_edge_detect, 140 events_interrupt_source, 140 events_path_selection, 140 extint_callback_type, 153 extint_detect, 153 extint_pull, 154 gclk_generator, 408 i2c_master_baud_rate, 192 i2c_master_callback, 193 i2c_master_inactive_timeout, 193 i2c_master_interrupt_flag, 193 i2c_master_start_hold_time, 193 i2c_slave_address_mode, 194 i2c_slave_callback, 194 i2c_slave_direction, 194 i2c_slave_sda_hold_time, 194 i2c_transfer_direction, 195 nvm_bod33_action, 229 nvm_bootloader_size, 229 nvm_cache_readmode, 229 nvm_command, 230 nvm_eeprom_emulator_size, 230 nvm_error, 231 nvm_sleep_power_mode, 231 nvm_wdt_early_warning_offset, 231 nvm_wdt_window_timeout, 232 port_pin_dir, 255 port_pin_pull, 255 rtc_calendar_alarm, 274 rtc_calendar_alarm_mask, 274 rtc_calendar_callback, 274 rtc_calendar_prescaler, 275 rtc_count_callback, 299 rtc_count_compare, 299 rtc_count_mode, 299 rtc_count_prescaler, 299 spi_addr_mode, 325 spi_callback, 325 spi_character_size, 326 spi_data_order, 326 spi_frame_format, 326 spi_interrupt_flag, 326 spi_mode, 327 spi_signal_mux_setting, 327 spi_transfer_mode, 327 system_clock_apb_bus, 409 system_clock_dfll_chill_cycle, 409 system_clock_dfll_loop_mode, 410 system_clock_dfll_quick_lock, 410 system_clock_dfll_stable_tracking, 410 system_clock_dfll_wakeup_lock, 410 system_clock_external, 410 system_clock_source, 411 system_interrupt_priority_level, 428 system_interrupt_vector_samd1x, 428 system_main_clock_div, 411 system_osc32k_startup, 411 system_osc8m_div, 412 system_osc8m_frequency_range, 412 system_pinmux_pin_dir, 436 system_pinmux_pin_pull, 436 system_pinmux_pin_sample, 437 system_reset_cause, 420 system_sleepmode, 420 system_voltage_reference, 421 system_xosc32k_startup, 412 system_xosc_startup, 413 tcc_callback, 471 tcc_channel_function, 472 tcc_clock_prescaler, 472 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 561 tcc_count_direction, 472 tcc_event0_action, 473 tcc_event1_action, 473 tcc_event_action, 473 tcc_event_generation_selection, 474 tcc_fault_blanking, 475 tcc_fault_capture_action, 475 tcc_fault_capture_channel, 475 tcc_fault_halt_action, 476 tcc_fault_keep, 476 tcc_fault_qualification, 476 tcc_fault_restart, 476 tcc_fault_source, 476 tcc_fault_state_output, 477 tcc_match_capture_channel, 477 tcc_output_invertion, 477 tcc_output_pattern, 477 tcc_ramp, 477 tcc_ramp_index, 478 tcc_reload_action, 478 tcc_wave_generation, 478 tcc_wave_output, 479 tcc_wave_polarity, 479 tc_callback, 541 tc_clock_prescaler, 541 tc_compare_capture_channel, 542 tc_counter_size, 542 tc_count_direction, 542 tc_event_action, 543 tc_reload_action, 543 tc_waveform_invert_output, 543 tc_wave_generation, 543 usart_callback, 371 usart_character_size, 372 usart_dataorder, 372 usart_parity, 372 usart_signal_mux_settings, 372 usart_stopbits, 373 usart_transceiver_type, 373 usart_transfer_mode, 373 wdt_callback, 553 wdt_period, 553 F Function Definitions ac_chan_clear_status, 25 ac_chan_disable, 24 ac_chan_enable, 23 ac_chan_get_config_defaults, 22 ac_chan_get_status, 25 ac_chan_is_ready, 24 ac_chan_set_config, 23 ac_chan_trigger_single_shot, 24 ac_disable, 21 ac_disable_events, 22 ac_enable, 21 ac_enable_events, 21 ac_get_config_defaults, 20 ac_init, 20 ac_is_syncing, 20 ac_reset, 19 ac_win_clear_status, 28 ac_win_disable, 27 ac_win_enable, 27 ac_win_get_config_defaults, 26 ac_win_get_status, 28 ac_win_is_ready, 28 ac_win_set_config, 26 adc_abort_job, 50 adc_clear_status, 42 adc_disable, 43 adc_disable_callback, 48 adc_disable_events, 44 adc_disable_interrupt, 47 adc_disable_pin_scan_mode, 51 adc_enable, 42 adc_enable_callback, 48 adc_enable_events, 43 adc_enable_interrupt, 46 adc_flush, 45 adc_get_config_defaults, 40 adc_get_job_status, 49 adc_get_status, 41 adc_init, 40 adc_read, 44 adc_read_buffer_job, 49 adc_register_callback, 47 adc_reset, 43 adc_set_gain, 50 adc_set_negative_input, 46 adc_set_pin_scan_mode, 50 adc_set_positive_input, 46 adc_set_window_mode, 45 adc_start_conversion, 44 adc_unregister_callback, 47 bod_clear_detected, 61 bod_disable, 61 bod_enable, 60 bod_get_config_defaults, 59 bod_is_detected, 61 bod_set_config, 60 dac_chan_abort_job, 81 dac_chan_disable, 74 dac_chan_disable_callback, 80 dac_chan_disable_output_buffer, 82 dac_chan_enable, 74 dac_chan_enable_callback, 79 dac_chan_enable_output_buffer, 81 dac_chan_get_config_defaults, 73 dac_chan_get_job_status, 80 dac_chan_set_config, 73 dac_chan_write, 74 dac_chan_write_buffer_job, 77 dac_chan_write_buffer_wait, 75 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 562 dac_chan_write_job, 77 dac_clear_status, 76 dac_disable, 72 dac_disable_events, 72 dac_enable, 71 dac_enable_events, 72 dac_get_config_defaults, 70 dac_get_status, 76 dac_init, 70 dac_is_syncing, 69 dac_register_callback, 78 dac_reset, 71 dac_unregister_callback, 79 dma_abort_job, 99 dma_add_descriptor, 99 dma_allocate, 100 dma_descriptor_create, 100 dma_descriptor_get_config_defaults, 101 dma_disable_callback, 101 dma_enable_callback, 102 dma_free, 102 dma_get_config_defaults, 102 dma_get_job_status, 103 dma_is_busy, 103 dma_register_callback, 103 dma_reset_descriptor, 104 dma_resume_job, 104 dma_start_transfer_job, 104 dma_suspend_job, 105 dma_trigger_transfer, 105 dma_unregister_callback, 105 dma_update_descriptor, 106 eeprom_emulator_commit_page_buffer, 121 eeprom_emulator_erase_memory, 120 eeprom_emulator_get_parameters, 120 eeprom_emulator_init, 120 eeprom_emulator_read_buffer, 123 eeprom_emulator_read_page, 122 eeprom_emulator_write_buffer, 122 eeprom_emulator_write_page, 121 events_ack_interrupt, 131 events_add_hook, 132 events_allocate, 132 events_attach_user, 133 events_create_hook, 133 events_del_hook, 134 events_detach_user, 134 events_disable_interrupt_source, 135 events_enable_interrupt_source, 135 events_get_config_defaults, 136 events_get_free_channels, 136 events_is_busy, 136 events_is_detected, 137 events_is_interrupt_set, 137 events_is_overrun, 138 events_is_users_ready, 139 events_release, 139 events_trigger, 139 extint_chan_clear_detected, 149 extint_chan_disable_callback, 152 extint_chan_enable_callback, 152 extint_chan_get_config_defaults, 147 extint_chan_is_detected, 149 extint_chan_set_config, 147 extint_disable_events, 146 extint_enable_events, 146 extint_get_current_channel, 152 extint_nmi_clear_detected, 150 extint_nmi_get_config_defaults, 148 extint_nmi_is_detected, 149 extint_nmi_set_config, 148 extint_register_callback, 150 extint_unregister_callback, 151 i2c_master_cancel_job, 180 i2c_master_disable, 173 i2c_master_disable_callback, 178 i2c_master_enable, 172 i2c_master_enable_callback, 177 i2c_master_get_config_defaults, 170 i2c_master_get_job_status, 180 i2c_master_init, 171 i2c_master_is_syncing, 170 i2c_master_lock, 169 i2c_master_read_packet_job, 178 i2c_master_read_packet_job_no_stop, 178 i2c_master_read_packet_wait, 173 i2c_master_read_packet_wait_no_stop, 174 i2c_master_register_callback, 176 i2c_master_reset, 173 i2c_master_send_stop, 176 i2c_master_unlock, 170 i2c_master_unregister_callback, 177 i2c_master_write_packet_job, 179 i2c_master_write_packet_job_no_stop, 179 i2c_master_write_packet_wait, 175 i2c_master_write_packet_wait_no_stop, 175 i2c_slave_cancel_job, 192 i2c_slave_clear_status, 188 i2c_slave_disable, 184 i2c_slave_disable_callback, 190 i2c_slave_disable_nack_on_address, 189 i2c_slave_enable, 184 i2c_slave_enable_callback, 190 i2c_slave_enable_nack_on_address, 188 i2c_slave_get_config_defaults, 182 i2c_slave_get_direction_wait, 186 i2c_slave_get_job_status, 192 i2c_slave_get_status, 187 i2c_slave_init, 183 i2c_slave_is_syncing, 182 i2c_slave_lock, 181 i2c_slave_read_packet_job, 191 i2c_slave_read_packet_wait, 186 i2c_slave_register_callback, 189 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 563 i2c_slave_reset, 184 i2c_slave_unlock, 181 i2c_slave_unregister_callback, 190 i2c_slave_write_packet_job, 191 i2c_slave_write_packet_wait, 185 nvm_erase_row, 226 nvm_execute_command, 226 nvm_get_config_defaults, 222 nvm_get_error, 228 nvm_get_fuses, 227 nvm_get_parameters, 223 nvm_is_page_locked, 228 nvm_is_ready, 223 nvm_read_buffer, 224 nvm_set_config, 222 nvm_update_buffer, 225 nvm_write_buffer, 224 port_get_config_defaults, 252 port_get_group_from_gpio_pin, 250 port_group_get_input_level, 251 port_group_get_output_level, 251 port_group_set_config, 253 port_group_set_output_level, 251 port_group_toggle_output_level, 252 port_pin_get_input_level, 253 port_pin_get_output_level, 254 port_pin_set_config, 253 port_pin_set_output_level, 254 port_pin_toggle_output_level, 254 rtc_calendar_clear_alarm_match, 270 rtc_calendar_clear_overflow, 270 rtc_calendar_disable, 265 rtc_calendar_disable_callback, 273 rtc_calendar_disable_events, 271 rtc_calendar_enable, 265 rtc_calendar_enable_callback, 273 rtc_calendar_enable_events, 271 rtc_calendar_frequency_correction, 267 rtc_calendar_get_alarm, 268 rtc_calendar_get_config_defaults, 264 rtc_calendar_get_time, 268 rtc_calendar_get_time_defaults, 264 rtc_calendar_init, 266 rtc_calendar_is_alarm_match, 270 rtc_calendar_is_overflow, 269 rtc_calendar_register_callback, 272 rtc_calendar_reset, 265 rtc_calendar_set_alarm, 268 rtc_calendar_set_time, 267 rtc_calendar_swap_time_mode, 266 rtc_calendar_unregister_callback, 272 rtc_count_clear_compare_match, 295 rtc_count_clear_overflow, 295 rtc_count_disable, 289 rtc_count_disable_callback, 298 rtc_count_disable_events, 296 rtc_count_enable, 289 rtc_count_enable_callback, 298 rtc_count_enable_events, 296 rtc_count_frequency_correction, 290 rtc_count_get_compare, 292 rtc_count_get_config_defaults, 288 rtc_count_get_count, 291 rtc_count_get_period, 294 rtc_count_init, 290 rtc_count_is_compare_match, 295 rtc_count_is_overflow, 294 rtc_count_register_callback, 297 rtc_count_reset, 289 rtc_count_set_compare, 292 rtc_count_set_count, 291 rtc_count_set_period, 293 rtc_count_unregister_callback, 297 spi_abort_job, 323 spi_attach_slave, 310 spi_disable, 311 spi_disable_callback, 320 spi_enable, 311 spi_enable_callback, 320 spi_get_config_defaults, 309 spi_get_job_status, 323 spi_get_job_status_wait, 324 spi_init, 310 spi_is_ready_to_read, 314 spi_is_ready_to_write, 313 spi_is_syncing, 324 spi_is_write_complete, 313 spi_lock, 312 spi_read, 315 spi_read_buffer_job, 321 spi_read_buffer_wait, 316 spi_register_callback, 319 spi_reset, 311 spi_select_slave, 319 spi_set_baudrate, 324 spi_slave_inst_get_config_defaults, 309 spi_transceive_buffer_job, 322 spi_transceive_buffer_wait, 318 spi_transceive_wait, 317 spi_unlock, 312 spi_unregister_callback, 320 spi_write, 314 spi_write_buffer_job, 321 spi_write_buffer_wait, 315 system_ahb_clock_clear_mask, 401 system_ahb_clock_set_mask, 401 system_apb_clock_clear_mask, 402 system_apb_clock_get_hz, 400 system_apb_clock_set_divider, 400 system_apb_clock_set_mask, 401 system_clock_init, 402 system_clock_source_dfll_get_config_defaults, 397 system_clock_source_dfll_set_config, 397 system_clock_source_disable, 398 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 564 system_clock_source_enable, 398 system_clock_source_get_hz, 399 system_clock_source_is_ready, 399 system_clock_source_osc32k_get_config_defaults, 395 system_clock_source_osc32k_set_config, 396 system_clock_source_osc8m_get_config_defaults, 396 system_clock_source_osc8m_set_config, 397 system_clock_source_write_calibration, 398 system_clock_source_xosc32k_get_config_defaults, 395 system_clock_source_xosc32k_set_config, 395 system_clock_source_xosc_get_config_defaults, 394 system_clock_source_xosc_set_config, 394 system_cpu_clock_get_hz, 400 system_cpu_clock_set_divider, 399 system_flash_set_waitstates, 403 system_gclk_chan_disable, 406 system_gclk_chan_enable, 406 system_gclk_chan_get_config_defaults, 405 system_gclk_chan_get_hz, 408 system_gclk_chan_is_enabled, 407 system_gclk_chan_is_locked, 407 system_gclk_chan_lock, 407 system_gclk_chan_set_config, 406 system_gclk_gen_disable, 405 system_gclk_gen_enable, 404 system_gclk_gen_get_config_defaults, 403 system_gclk_gen_get_hz, 408 system_gclk_gen_is_enabled, 405 system_gclk_gen_set_config, 404 system_gclk_init, 403 system_get_device_id, 418 system_get_reset_cause, 420 system_init, 418 system_interrupt_clear_pending, 426 system_interrupt_disable, 425 system_interrupt_disable_global, 424 system_interrupt_enable, 425 system_interrupt_enable_global, 424 system_interrupt_enter_critical_section, 423 system_interrupt_get_active, 425 system_interrupt_get_priority, 427 system_interrupt_is_enabled, 424 system_interrupt_is_global_enabled, 423 system_interrupt_is_pending, 425 system_interrupt_leave_critical_section, 423 system_interrupt_set_pending, 426 system_interrupt_set_priority, 427 system_is_debugger_present, 417 system_peripheral_lock, 244 system_peripheral_unlock, 245 system_pinmux_get_config_defaults, 433 system_pinmux_get_group_from_gpio_pin, 435 system_pinmux_group_set_config, 434 system_pinmux_group_set_input_sample_mode, 435 system_pinmux_pin_get_mux_position, 435 system_pinmux_pin_set_config, 434 system_pinmux_pin_set_input_sample_mode, 436 system_reset, 420 system_set_sleepmode, 419 system_sleep, 419 system_voltage_reference_disable, 419 system_voltage_reference_enable, 418 tcc_clear_status, 466 tcc_disable, 459 tcc_disable_circular_buffer_compare, 470 tcc_disable_circular_buffer_top, 469 tcc_disable_double_buffering, 467 tcc_disable_events, 459 tcc_enable, 459 tcc_enable_circular_buffer_compare, 470 tcc_enable_circular_buffer_top, 468 tcc_enable_double_buffering, 467 tcc_enable_events, 458 tcc_force_double_buffer_update, 468 tcc_get_capture_value, 462 tcc_get_config_defaults, 456 tcc_get_count_value, 461 tcc_get_status, 465 tcc_init, 457 tcc_is_running, 465 tcc_is_syncing, 456 tcc_lock_double_buffer_update, 467 tcc_reset, 460 tcc_restart_counter, 462 tcc_set_compare_value, 463 tcc_set_count_direction, 460 tcc_set_count_value, 461 tcc_set_double_buffer_compare_values, 471 tcc_set_double_buffer_top_values, 469 tcc_set_pattern, 464 tcc_set_ramp_index, 465 tcc_set_top_value, 463 tcc_stop_counter, 462 tcc_toggle_count_direction, 460 tcc_unlock_double_buffer_update, 468 tc_clear_status, 541 tc_disable, 536 tc_disable_events, 535 tc_enable, 536 tc_enable_events, 534 tc_get_capture_value, 538 tc_get_config_defaults, 532 tc_get_count_value, 536 tc_get_status, 540 tc_init, 533 tc_is_syncing, 532 tc_reset, 535 tc_set_compare_value, 539 tc_set_count_value, 537 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 565 tc_set_top_value, 539 tc_start_counter, 537 tc_stop_counter, 537 tc_sync_read_count, 538 tc_update_double_buffer, 538 usart_abort_job, 368 usart_disable, 369 usart_disable_callback, 365 usart_disable_transceiver, 363 usart_enable, 369 usart_enable_callback, 365 usart_enable_transceiver, 363 usart_get_config_defaults, 369 usart_get_job_status, 368 usart_init, 370 usart_is_syncing, 371 usart_lock, 359 usart_read_buffer_job, 367 usart_read_buffer_wait, 362 usart_read_job, 366 usart_read_wait, 360 usart_register_callback, 364 usart_reset, 371 usart_unlock, 360 usart_unregister_callback, 364 usart_write_buffer_job, 366 usart_write_buffer_wait, 361 usart_write_job, 365 usart_write_wait, 360 wdt_clear_early_warning, 550 wdt_disable_callback, 552 wdt_enable_callback, 552 wdt_get_config_defaults, 549 wdt_is_early_warning, 550 wdt_is_locked, 550 wdt_is_syncing, 548 wdt_register_callback, 551 wdt_reset_count, 551 wdt_set_config, 549 wdt_unregister_callback, 551 M Macro Definitions AC_CHAN_STATUS_INTERRUPT_SET, 19 AC_CHAN_STATUS_NEG_ABOVE_POS, 19 AC_CHAN_STATUS_POS_ABOVE_NEG, 19 AC_CHAN_STATUS_UNKNOWN, 19 AC_WIN_STATUS_ABOVE, 18 AC_WIN_STATUS_BELOW, 18 AC_WIN_STATUS_INSIDE, 18 AC_WIN_STATUS_INTERRUPT_SET, 18 AC_WIN_STATUS_UNKNOWN, 18 ADC_STATUS_OVERRUN, 40 ADC_STATUS_RESULT_READY, 39 ADC_STATUS_WINDOW, 39 DAC_STATUS_CHANNEL_0_EMPTY, 69 DAC_STATUS_CHANNEL_0_UNDERRUN, 69 DAC_TIMEOUT, 69 DMA_INVALID_CHANNEL, 99 EEPROM_EMULATOR_ID, 119 EEPROM_MAJOR_VERSION, 119 EEPROM_MINOR_VERSION, 119 EEPROM_PAGE_SIZE, 119 EEPROM_REVISION, 119 EIC_NUMBER_OF_INTERRUPTS, 145 EVSYS_ID_GEN_NONE, 131 EXTINT_CLK_GCLK, 146 EXTINT_CLK_ULP32K, 146 FEATURE_AC_RUN_IN_STANDY_PAIR_COMPARATOR, 18 FEATURE_RTC_CONTINUOUSLY_UPDATED, 264, 288 FEATURE_SPI_ERROR_INTERRUPT, 308 FEATURE_SPI_HARDWARE_SLAVE_SELECT, 308 FEATURE_SPI_SLAVE_SELECT_LOW_DETECT, 308 FEATURE_SPI_SYNC_SCHEME_VERSION_2, 308 FEATURE_TC_DOUBLE_BUFFERED, 529 FEATURE_TC_IO_CAPTURE, 530 FEATURE_TC_READ_SYNC, 530 FEATURE_TC_STAMP_PW_CAPTURE, 529 FEATURE_TC_SYNCBUSY_SCHEME_VERSION_2, 529 I2C_SLAVE_STATUS_ADDRESS_MATCH, 167 I2C_SLAVE_STATUS_BUS_ERROR, 169 I2C_SLAVE_STATUS_CLOCK_HOLD, 168 I2C_SLAVE_STATUS_COLLISION, 169 I2C_SLAVE_STATUS_DATA_READY, 168 I2C_SLAVE_STATUS_RECEIVED_NACK, 169 I2C_SLAVE_STATUS_REPEATED_START, 168 I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT, 168 I2C_SLAVE_STATUS_STOP_RECEIVED, 168 PINMUX_DEFAULT, 308, 359 PINMUX_UNUSED, 308, 359 PORTA, 250 PORTB, 250 PORTC, 250 PORTD, 250 SPI_TIMEOUT, 308 SYSTEM_PERIPHERAL_ID, 243 SYSTEM_PINMUX_GPIO, 433 TCC_NUM_CHANNELS, 455 TCC_NUM_FAULTS, 455 TCC_NUM_WAVE_OUTPUTS, 455 TCC_STATUS_CAPTURE_OVERFLOW, 454 TCC_STATUS_CHANNEL_MATCH_CAPTURE, 453 TCC_STATUS_CHANNEL_OUTPUT, 453 TCC_STATUS_COUNTER_EVENT, 454 TCC_STATUS_COUNTER_RETRIGGERED, 454 TCC_STATUS_COUNT_OVERFLOW, 454 TCC_STATUS_NON_RECOVERABLE_FAULT_OCCUR, 453 TCC_STATUS_NON_RECOVERABLE_FAULT_PRESENT, 453 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 566 TCC_STATUS_RAMP_CYCLE_INDEX, 454 TCC_STATUS_RECOVERABLE_FAULT_OCCUR, 453 TCC_STATUS_RECOVERABLE_FAULT_PRESENT, 454 TCC_STATUS_STOPPED, 455 TCC_STATUS_SYNC_READY, 454 TC_STATUS_CAPTURE_OVERFLOW, 530 TC_STATUS_CHANNEL_0_MATCH, 530 TC_STATUS_CHANNEL_1_MATCH, 530 TC_STATUS_CHN0_BUFFER_VALID, 531 TC_STATUS_CHN1_BUFFER_VALID, 531 TC_STATUS_COUNT_OVERFLOW, 530 TC_STATUS_PERIOD_BUFFER_VALID, 531 TC_STATUS_SYNC_READY, 530 TC_WAVEFORM_INVERT_CC0_MODE, 532 TC_WAVEFORM_INVERT_CC1_MODE, 532 TC_WAVE_GENERATION_MATCH_FREQ_MODE, 531 TC_WAVE_GENERATION_MATCH_PWM_MODE, 531 TC_WAVE_GENERATION_NORMAL_FREQ_MODE, 531 TC_WAVE_GENERATION_NORMAL_PWM_MODE, 531 USART_TIMEOUT, 359 _TCC_CHANNEL_ENUM_LIST, 455 _TCC_ENUM, 455 _TCC_WO_ENUM_LIST, 455 P Public Variable Definitions descriptor_section, 97 S Structure Definitions ac_chan_config, 16 ac_config, 17 ac_events, 17 ac_module, 17 ac_win_config, 17 adc_config, 37 adc_correction_config, 38 adc_events, 38 adc_module, 39 adc_pin_scan_config, 39 adc_window_config, 39 bod_config, 59 dac_chan_config, 68 dac_config, 68 dac_events, 69 dac_module, 69 dma_descriptor_config, 97 dma_events_config, 98 dma_resource, 98 dma_resource_config, 98 eeprom_emulator_parameters, 118 events_config, 131 events_hook, 131 events_resource, 131 extint_chan_conf, 144 extint_events, 145 extint_nmi_conf, 145 i2c_master_config, 165 i2c_master_module, 166 i2c_master_packet, 166 i2c_slave_config, 166 i2c_slave_module, 167 i2c_slave_packet, 167 nvm_config, 221 nvm_fusebits, 221 nvm_parameters, 222 port_config, 249 rtc_calendar_alarm_time, 262 rtc_calendar_config, 263 rtc_calendar_events, 263 rtc_calendar_time, 263 rtc_count_config, 287 rtc_count_events, 288 spi_config, 306 spi_master_config, 306 spi_module, 306 spi_slave_config, 307 spi_slave_inst, 307 spi_slave_inst_config, 307 system_clock_source_dfll_config, 391 system_clock_source_osc32k_config, 392 system_clock_source_osc8m_config, 392 system_clock_source_xosc32k_config, 392 system_clock_source_xosc_config, 393 system_gclk_chan_config, 393 system_gclk_gen_config, 393 system_pinmux_config, 433 tcc_capture_config, 448 tcc_config, 448 tcc_counter_config, 449 tcc_events, 449 tcc_input_event_config, 450 tcc_match_wave_config, 450 tcc_module, 451 tcc_non_recoverable_fault_config, 451 tcc_output_event_config, 451 tcc_pins_config, 451 tcc_recoverable_fault_config, 452 tcc_wave_extension_config, 452 tc_16bit_config, 526 tc_32bit_config, 527 tc_8bit_config, 527 tc_config, 527 tc_events, 528 tc_module, 529 tc_pwm_channel, 529 usart_config, 358 usart_module, 358 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 567 wdt_conf, 548 T Type Definitions ac_callback_t, 16 dac_callback_t, 68 dma_callback_t, 97 events_interrupt_hook, 130 extint_callback_t, 144 spi_callback_t, 305 tcc_callback_t, 448 tc_callback_t, 526 usart_callback_t, 357 wdt_callback_t, 548 U Union Definitions spi_config.mode_specific, 306 tcc_config.__unnamed__, 449 tc_config.__unnamed__, 528 AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 568 Document Revision History Doc. Rev. Date Comments 42359A 12/2014 Initial release. AT09280: ASF Manual (SAM D10) [APPLICATION NOTE] 42359A-SAMD10-01/2015 569 Atmel Corporation 1600 Technology Drive, San Jose, CA 95110 USA T: (+1)(408) 441.0311 F: (+1)(408) 436.4200 | www.atmel.com © 2015 Atmel Corporation. / Rev.: 42359A-SAMD10-01/2015 ® ® Atmel , Atmel logo and combinations thereof, Enabling Unlimited Possibilities , and others are registered trademarks or trademarks of Atmel Corporation in U.S. and other ® ® ® countries. ARM , ARM Connected logo, Cortex and others are the registered trademarks or trademarks of ARM Ltd. Other terms and product names may be trademarks of others. DISCLAIMER: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. 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