watchdog 2021

[skywatch]

I have been reading through the posts on watchdogging and still not sure about it, so here is a question that perhaps someone can answer.......

Is the below code snippet the right way to use watchdog in 2.3.2? Do I need the #include <avr/wdt.h> is it already in the mysensors package?

#include <avr/wdt.h>
#include <MySensors.h>

void setup()
{
  // Setup locally attached sensors
  wdt_disable();
  wait(250);
  wdt_enable(WDTO_8S);
}

void presentation()
{
  // Present locally attached sensors
}

void loop()
{
  // Send locally attached sensor data here
  wdt_reset();
}

This is to use on a gateway but is the same method implemented on sleeping nodes?

I will be using the minicore bootloaders which I believe are optiboot forks.

Thanks.

[Melih Kulig]

@skywatch, I don't know if you're still looking for the answer, but in case you are, or anyone else who hits through google search, from what I understand reading this page: https://www.nongnu.org/avr-libc/user-manual/group__avr__watchdog.html , you can set your watchdog timer with wdt_enable(time constant), time constant is typically in WDTO_XS format, where X is the seconds, however not all values are available for all processors, please see the link to check which values are supported.

Next thing to do is including wdt_reset() on your loop. This will reset the timer. If the timer isn't reset by the time your counter expires, watchdog will trigger.

[skywatch]

@Melih-Kulig Thanks - #i actually used the code above and it has been working OK for the last 10 days, so no bad effect. I don't know if the watchdog has had to kick in yet but it seems not.

[virtualmkr]

Hi all,
I'd like to add, there is no need to call wdt_reset() explicitly in loop().
This already takes place before each loop() call in the MySensors library code behind function doYield():
see: MySensorsCore.cpp#L619

And hwWatchdogReset() is an HW abstraction of wdt_reset() for AVR architecture:
/hal/architecture/AVR/MyHwAVR.h#L71

My call stack from main() to doYield() is:

>	MySensorsProject2.exe!doYield() Line 650	C++
 	MySensorsProject2.exe!_processInternal() Line 74	C++
 	MySensorsProject2.exe!_process() Line 91	C++
 	MySensorsProject2.exe!main(int argc, char * * argv) Line 343	C++

[skywatch]

@virtualmkr That is useflul to know - thanks! - As it happens I think I had my first wdt 'kick' early this morning as the Gateway with the wdt on was showing as up for 3 hours instead of the 4 days I was expecting, so it restarted and all is still working ;)