WDT Callback didn`t execute when the system reset

RE: WDT Callback didn`t execute when the system reset

Nedaa_H_Ahmed — Tue, 18 Mar 2025 09:43:55 GMT

I tried to store the data on the flash in the WDT callback, but unfortunately, it didn't store. Is it because the WDT callback should be finished within 61us?

Another question: How can I stop the WDT? I called wdt_disable inside the WDT callback to stop it, but there was no difference. The reset occurs immediately

RE: WDT Callback didn`t execute when the system reset

Vidar Berg — Tue, 18 Mar 2025 06:54:52 GMT

It would have to be stored to NV memory (RRAM) to be retained through the reset, but you would have to stop the WD to have time to store the data to flash. Alternatively you can consider using the task watchdog with the HW WD as fallback https://docs.zephyrproject.org/latest/services/task_wdt/index.html. I assume you will also need to rely on the low level nrfx APIs to store the data to RRAM to allow it to be performed from the ISR.

[quote user="Nedaa_H_Ahmed"]

I have another question please, how can I make sure that the callback is called

I added only this line in the WDT callback to indicate that the callback is executed but the LED didn`t turn on

[/quote]

Even if the callback is invoked, the led glitch may be too short to notice. I suggest placing a breakpoint in the callback.

RE: WDT Callback didn`t execute when the system reset

Nedaa_H_Ahmed — Mon, 17 Mar 2025 13:55:32 GMT

Is there any other solution that can achieve the requirements? I want only to preserve the value of SP, and LR when the WDT happened. Should I store them in flash, or the operation will take timer more than 61us

I have another question please, how can I make sure that the callback is called

I added only this line in the WDT callback to indicate that the callback is executed but the LED didn`t turn on

gpio_pin_set_dt(&led, 0); //when I added this line in any other place, the LED turns on

RE: WDT Callback didn`t execute when the system reset

Vidar Berg — Mon, 17 Mar 2025 13:47:03 GMT

No, the RAM is cleared.

RE: WDT Callback didn`t execute when the system reset

Nedaa_H_Ahmed — Mon, 17 Mar 2025 13:40:35 GMT

Can I do any RAM retention settings to save these data after WDT reset?

RE: WDT Callback didn`t execute when the system reset

Vidar Berg — Mon, 17 Mar 2025 13:34:45 GMT

All linker sections in RAM will be cleared.

RE: WDT Callback didn`t execute when the system reset

Nedaa_H_Ahmed — Mon, 17 Mar 2025 13:33:49 GMT

But I save the data in the noinit section. Does this section will be reset?

RE: WDT Callback didn`t execute when the system reset

Vidar Berg — Mon, 17 Mar 2025 13:24:31 GMT

Hello,

The RAM is reset following WD reset so I'm afraid you will not be able to retain this data in RAM anyway. From the datasheet:

Best regards,

Vidar