Watchdog fails...

  • It appears my fipy software stalled yet, the watchdog never kicked in ie still in freeze mode after 12hours? I have a timer that feeds the WD every 60 seconds which has stalled becuase it doesnt respond to anything yet why didn't restart chip?

    Is the watchdog failsafe?

  • @misterlisty I did not fully analyze Pycom's implementation of the Watchdog, As far as I understand, the event they trigger is an interrupt, not reset. Which means, that in a full this interrupt fails too. Using the RTC it is possible to set up an WDT which pulls reset on expiry, but that one seems not to be used.

  • @robert-hh Why is this the case? Isnt this the point of the watchdog?

  • @misterlisty No, the watchdog is not failsafe. You find similar observations like yours in the forum. If you need a robust watchdog, you have to attach an external device. There are dedicated chips for that purpose. You can also use an '555 timer for that.
    Pycom may also consider to use the PIC on the expansion boards for that, unless that devices also has to be assumed as not sufficiently reliable.

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