Reinitialize RTC upon watchdog reset

[timothy0508]

In my application, I have a watchdog timer that resets every 45 seconds if not fed. I also have an RTC. The application records sensor samples, along with timestamps from the RTC.

Problem is, when there is a watchdog reset, the RTC is re-initialized to default date and time. This messes up the sample/timestamp collection.

• Are the RTC time/date values still maintained even when there is a watchdog reset?
• Would it make sense to skip setting the default date/time when a watchdog reset has been detected?

Thanks.

[waclawek.jan · Accepted solution]

Which STM32?

> Are the RTC time/date values still maintained even when there is a watchdog reset?

Yes. Your problems are caused by using Cube.

> Would it make sense to skip setting the default date/time when a watchdog reset has been detected?

Yes. You need to detect, if RTC is already set - see RTC_ISR.INITS flag - and act accordingly.

JW

[timothy0508]

STM32L4

Thanks. I just tested this out and it worked. The RTC values are maintained even with a watchdog reset.

Just needed to be absolutely sure.

Tim

[miroslav]

Hello, I have a related question.
After wake-up by RTC, I want to set time again if it drifted from accurate values. 
But when I try to set new time it returns error.

So how to set new time values after reset?