nRF52832 resets ~20 s after entering System OFF (watchdog)

[mento]

We are using nRF52832 with NCS(v2.9.2)/Zephyr and the watchdog (20 s timeout). When the application enters System OFF (e.g. after idle), the device goes to sleep but then resets after about 20 seconds. We see the bootloader and application start again, so it looks like a watchdog reset.
We feed the watchdog before starting the shutdown sequence and before writing the SYSTEMOFF register, but the device still resets about 20 seconds later. We cannot disable the watchdog on nRF52832 (no STOP support).
Question: What is the recommended way to enter System OFF on nRF52832 when the watchdog is enabled, so that the device stays off and is not reset by the watchdog after ~20 seconds?
Thank you.

[Vidar Berg]

Hello,

It is difficult to track the actual number of reboots when you are powering off RAM as there will be multiple resets until the WD finally times out. Did you remove the code section as I suggested? If you are still experiencing issues after this, please upload your updated project so I can try to run it again.

[mento]

Hello Vidar,Quick update: the recommended System OFF entry path (sys_poweroff() on NCS v2.9.2 / Zephyr) is working fine on nRF52832.The earlier “unexpected restart” behavior was on our side. After investigation we confirmed the device was actually waking from System OFF (RESETREAS indicates OFF wake), and the wake was triggered by our board/wakeup pin behavior. After correcting the board-side issue / configuration, the unexpected wakes are gone and System OFF + GPIO wake works as expected. Watchdog enablement is not an issue in this fixed setup.Thanks again for the guidance.