Clarification needed - MCUboot + Watchdog (SDK v2.9.0)

[uknoblic]

Dear nordic team,

even if enabled for mcuboot via CONFIG_WATCHDOG / CONFIG_BOOT_WATCHDOG_FEED, our device performs a reset when swapping the image. More precisely: when erasing the flash. When a look at the source code, it seems that the watchdog is not re-set during the erase operation. Is this correct? In that case, the time-out for the wdt has to be set accordingly, taking into consideration the maximum time it needs to erase the sectors for the image (e.g. roughly 256 pages * 85 ms = 21760 ms). Could you please confirm? Would'nt it make sense to add MCUBOOT_WATCHDOG_FEED() to the erase operation as wel int that case?

Regards

Ulf

[Einar Thorsrud]

Hi Ulf,

I see the same as you, but I am not able to explain why there is no feedign of the watchdog while erasing. I am checking this internally and will get back to you.

That said, generally the watchdog is only intended as a last resort for unrecoverable errors that should normally never happen, and therefor using a fairly long timeout for the watchdog is acceptable and sensible in most products.

Br,

Einar