How to use WDT to reset device in nRF52832

[chianglin]

HI,

I am using ".\nRF5_SDK_15.3.0_59ac345\examples\peripheral\wdt" to test “watch dog timer function.

My use case is:

1. If the program is not execute over following pint (please find follow image) in some time, the system will reboot.

2. Otherwise, the system will not reboot.

How can I modify the program?

Thank you,

Chianglin

[Vidar Berg]

Hi Chianglin,

You can call nrf_drv_wdt_channel_feed() to reload the WD timer in your for loop. But keep in mind that the WD will continue run in sleep with the default configuration so the WD timeout must be longer than expected the sleep time. The other alternative is to select the "<8=> Pause in SLEEP, Run in HALT " option to pause the timer while asleep. You may be impacted by this errata if you go for the latter: [88] WDT: Increased current consumption when configured to pause in System ON idle

[chianglin]

Hi Vidar,,

It's work now, thank you.

Can I ask an another question?

What the purpose of "__SEV()" and "__WFE()“？

Thank you,

Chianglin

[Vidar Berg]

Hi Chianglin,

These two instructions are used to clear the internal "event" register. I don't think it's strictly necessary here, it could have been just one __WFE instruction. Here's another thread which provides more details: https://devzone.nordicsemi.com/f/nordic-q-a/490/how-do-you-put-the-nrf51822-chip-to-sleep