nRF9160 watchdog timer can reset all hardfault?

[bbslhb]

Hello, rols and hkn:

I got two different answer about watchdog and hardfault in devzone.

1. watchdog can't reset hardfault.    https://devzone.nordicsemi.com/f/nordic-q-a/5837/watchdog-not-working-when-in-hardfault

2. watchdog can reset hardfault.    https://devzone.nordicsemi.com/support/232678

For all hardfaults caused by all cores such as modem core and MCU core,  and for all peripherals in nRF9160SIP, can watchdog timer reset all those possible hardfault?

All reset sources including watchdog timer can reset CPU and modem according to 5.1.5.8 Reset behavior of nRF9160_PS_v1.0.pdf, but I don't think CPU and modem are equal to hardfault. I think hardfault is more powerfull then CPU and modem fault.

RK, Håkon Alseth

[Håkon Alseth]

Hi,

 

A watchdog is a peripheral which has one main purpose; to reset if the timer expires.

If a fault-condition occurs, like HardFault or UsageFault, the watchdog will reset when the watchdog-timer expires.

 

The watchdog peripheral has the option to generate an event 2 LFCLK clock cycles prior to a reset occurring, so that the application can potentially be warned that a reset is coming soon.

If you are stuck in HardFault; this event cannot be processed, as HardFault is a hard-coded high priority interrupt handler.

 

Kind regards,

Håkon

[bbslhb]

I means system stuck in HardFault.

Our custom board 5V power supply is controled by a certain GPIO of nRF9160SIP.

Our product will be recalled if stuck in HardFault which caused the certain GPIO can't be set to HIGH or LOW.

[Håkon Alseth]

You will get a watchdog reset if the timer expires. However; you will not get the watchdog event if you are stuck in a high priority interrupt.

 

Reset will occur.

[bbslhb]

Got that. Thanks.

A reset in HardFault stuck is enough. Watchdog event is not necessary.