RTCZero
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20 hours ago •
arduino-libraries
arduino-libraries
Disable SAMD21 SysTick interrupt during sleep
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This addresses a problem I experienced using an Adafruit Feather M0 where the board would suddenly refuse to wake up after a random time (4 - 12 hours). I found the solution in a discussion on the Atmel community forum: https://community.atmel.com/comment/2625116#comment-2625116.
In summary, due to a hardware bug on the SAMD21 platform it is possible for the SysTick interrupt to fire during wakeup before the RAM has had time to reinitialise which results in a hard fault. This can be prevented by disabling the SysTick interrupt before sleep and then reenabling it immediately after wakeup.
SysTick->CTRL &= ~SysTick_CTRL_TICKINT_Msk; // Disable SysTick interrupt
__DSB(); // Data sync to ensure outgoing memory accesses complete
__WFI(); // Wait for interrupt (places device in sleep mode)
SysTick->CTRL |= SysTick_CTRL_TICKINT_Msk; // Enable SysTick interrupt
After making this change the board has now been running for over two weeks with no problems.
Memory usage change @ 42b760b83394dba79ee89d5e82fe476aa857ad85
| Board | flash | % | RAM for global variables | % |
|---|---|---|---|---|
| arduino:samd:arduino_zero_edbg | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkr1000 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrfox1200 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrgsm1400 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrnb1500 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrvidor4000 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwan1300 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwan1310 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwifi1010 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrzero | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:nano_33_iot | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
Click for full report table
| Board | examples/Epoch flash |
% | examples/Epoch RAM for global variables |
% | examples/SimpleRTC flash |
% | examples/SimpleRTC RAM for global variables |
% | examples/SimpleRTCAlarm flash |
% | examples/SimpleRTCAlarm RAM for global variables |
% | examples/SleepRTCAlarm flash |
% | examples/SleepRTCAlarm RAM for global variables |
% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| arduino:samd:arduino_zero_edbg | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkr1000 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrfox1200 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrgsm1400 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrnb1500 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrvidor4000 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwan1300 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwan1310 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwifi1010 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrzero | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:nano_33_iot | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
Click for full report CSV
Board,examples/Epoch<br>flash,%,examples/Epoch<br>RAM for global variables,%,examples/SimpleRTC<br>flash,%,examples/SimpleRTC<br>RAM for global variables,%,examples/SimpleRTCAlarm<br>flash,%,examples/SimpleRTCAlarm<br>RAM for global variables,%,examples/SleepRTCAlarm<br>flash,%,examples/SleepRTCAlarm<br>RAM for global variables,%
arduino:samd:arduino_zero_edbg,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkr1000,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrfox1200,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrgsm1400,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrnb1500,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrvidor4000,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwan1300,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwan1310,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwifi1010,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrzero,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:nano_33_iot,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
![github-actions[bot] avatar](https://avatars.githubusercontent.com/in/15368?v=4 "Published by a pub.dev verified publisher"){kind=small}
Memory usage change @ 89695db5c3bae8c9184607514e5a2297092cc2e2
| Board | flash | % | RAM for global variables | % |
|---|---|---|---|---|
| arduino:samd:arduino_zero_edbg | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkr1000 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrfox1200 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrgsm1400 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrnb1500 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrvidor4000 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwan1300 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwan1310 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrwifi1010 | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:mkrzero | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
| arduino:samd:nano_33_iot | :small_red_triangle: 0 - +20 | 0.0 - +0.01 | 0 - 0 | 0.0 - 0.0 |
Click for full report table
| Board | examples/Epoch flash |
% | examples/Epoch RAM for global variables |
% | examples/SimpleRTC flash |
% | examples/SimpleRTC RAM for global variables |
% | examples/SimpleRTCAlarm flash |
% | examples/SimpleRTCAlarm RAM for global variables |
% | examples/SleepRTCAlarm flash |
% | examples/SleepRTCAlarm RAM for global variables |
% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| arduino:samd:arduino_zero_edbg | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkr1000 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrfox1200 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrgsm1400 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrnb1500 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrvidor4000 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwan1300 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwan1310 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrwifi1010 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:mkrzero | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
| arduino:samd:nano_33_iot | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 20 | 0.01 | 0 | 0.0 |
Click for full report CSV
Board,examples/Epoch<br>flash,%,examples/Epoch<br>RAM for global variables,%,examples/SimpleRTC<br>flash,%,examples/SimpleRTC<br>RAM for global variables,%,examples/SimpleRTCAlarm<br>flash,%,examples/SimpleRTCAlarm<br>RAM for global variables,%,examples/SleepRTCAlarm<br>flash,%,examples/SleepRTCAlarm<br>RAM for global variables,%
arduino:samd:arduino_zero_edbg,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkr1000,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrfox1200,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrgsm1400,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrnb1500,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrvidor4000,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwan1300,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwan1310,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrwifi1010,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:mkrzero,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0
arduino:samd:nano_33_iot,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,20,0.01,0,0.0