Software Reset to imitate Pin Reset

RE: Software Reset to imitate Pin Reset

dejans — Thu, 11 Dec 2025 11:15:27 GMT

Hi,

[quote user="DamoL"]I take it this means there is no other way of triggering a hard (pin) reset through software?[/quote]

Commonly you would need to bind pin activation to something that would act as trigger.
Best regards,
Dejan

RE: Software Reset to imitate Pin Reset

hmolesworth — Tue, 09 Dec 2025 17:25:28 GMT

Some designs implement a software-triggered power-on reset by mistake, a feature usually discovered after a few thousand devices are in the field; note this feature is heavily dependent on the power source and current capability of the source. Tie two or more GPIO pins together on the board and first set both (all) outputs low then configure all to High-Drive outputs. When a reset is required at some future time or event set one (or more) pin high, either in software or hardware via PPI from an impossible Event such as timer overflow or (say) push-button input.

Not a Nordic-supported solution, I should add :-)

Edit: After re-reading the original post I see this is not an option, but maybe since ram is a suspect set all RAM[].POWER to power down all ram, then without using the stack wait for a large number of CPU cycles then again without using the stack issue a soft reset. Hopefully the ram will have decayed. Other option is to zero all ram without using the stack then issue the soft reset.

RE: Software Reset to imitate Pin Reset

DamoL — Tue, 09 Dec 2025 17:03:19 GMT

We already configure and start the watchdog at the start of the program. The point is you cannot reconfigure after that. Not necessarily a problem, we will just have to find another way of working with the watchdog.
I take it this means there is no other way of triggering a hard (pin) reset through software?

RE: Software Reset to imitate Pin Reset

dejans — Tue, 09 Dec 2025 15:21:34 GMT

Hi Damien,

[quote user="DamoL"]Doesn't look like you can reconfigure during runtime without reset. [/quote]

Can you elaborate on this? You could try to configure WDT before it is started. Is this valid option for you?

Best regards,
Dejan

RE: Software Reset to imitate Pin Reset

DamoL — Tue, 09 Dec 2025 08:33:02 GMT

"The watchdog must be configured before it is started. After it is started, the watchdog’s configuration registers, which comprise registers CRV, RREN, and CONFIG, will be blocked for further configuration. ... When the device starts running again, after a reset, or waking up from OFF mode, the watchdog configuration registers will be available for configuration again."

Doesn't look like you can reconfigure during runtime without reset.

Thanks,

Damien

RE: Software Reset to imitate Pin Reset

dejans — Fri, 05 Dec 2025 13:25:53 GMT

Hi Damien,

[quote user="DamoL"]What I thought I could try, is disabling it, setting it to a shorter period, then enabling it, but I unless I am doing something else wrong, I don't think reconfiguring the interval is allowed. [/quote]

It should be possible to reconfigure WDT. Please refer to nrf9160 WDT documentation.

Best regards,
Dejan

RE: Software Reset to imitate Pin Reset

DamoL — Thu, 04 Dec 2025 14:55:15 GMT

Hi Dejans,

Yes, the watchdog definitely works. I block it and it resets after 5 minutes. We already use this feature, specifically for the rare case where something goes wrong, the modem gets turned on, but never turned off.

What I thought I could try, is disabling it, setting it to a shorter period, then enabling it, but I unless I am doing something else wrong, I don't think reconfiguring the interval is allowed.

The main point though, is that I need a way to imitate doing a Pin Reset (holding nRESET line low), in software, I figured WDT reset is probably the closest, unless there is another way?

Thanks,
Damien

RE: Software Reset to imitate Pin Reset

dejans — Thu, 04 Dec 2025 14:22:31 GMT

Hi Damien,

Are you trying to disable watchdog, reconfigure it to a shorter interval and then trigger the reset this way?

If the device resets after 5 minutes, you might try to enable watchdog timer expiry after some shorter time, for example 5 seconds. Can you verify that when you block feeding the watchdog for 5 minutes device restarts?

Best regards,
Dejan