Recovering from PMIC watchdog expiration

Firmware Device OS
1

I noticed on device OS 1.5.4 that if the PMIC watchdog is enabled, that after the watchdog expires, the boron needs a complete power cycle for it to power on again.

Observations:

  • Boron configures watchdog for 0b01 (40 seconds)
  • PMIC STAT LED rapidly blinking since there is no battery.
  • Boron EN pin is disabled so that the Boron is unable to service the PMIC watchdog
  • PMIC STAT LED rapidly blinks until watchdog expires, then turns off.
  • Boron EN pin is unasserted so that it can boot up.
  • Problem: Boron doesn’t boot up at all. Even when leaving it powered and running for 20 minutes.

Is there a way to recover from a watchdog expiration so that the Boron can boot up again? Currently I need to disable power to the entire unit for 10-20 minutes for it to boot up after a PMIC watchdog expiration. If I disable the watchdog then this issue doesn’t happen.

2

Hi Dustin,

Could you please show your code where you enable the watchdog?
I’d like to try and replicate this.

3

Hi!

I set the watchdog and reset it with the following code (in the beginning of setup():
PMIC pmic;
pmic.begin();
pmic.enableBuck();

// later on in setup()
pmic.setWatchdog(0b01);
pmic.resetWatchdog();

Thanks,
Dustin