STM32L475RC RTC Issue?

[adrian]

Are there any known issues with the RTC Wakeup on the STM32L475?

I cannot get it to work, I've copied the code exactly as it appears in the STOP2_PWR example, but no matter what I do the ISR does not get called.

If I check the registers I can see the the wakeup timer has elapsed, the interrupt is enabled.

I'm totally at a loss here.

I did ask about a week ago, but have had no response.

[Tesla DeLorean]

ST Staff would need to be contacted via the FAE supporting your project, or the Online Support Request.

Not an area I've had cause to dig into at this point.

https://community.st.com/s/question/0D50X0000A1k8fJSQQ/halrtcexsetwakeuptimerit-issue-stm32l475rc

[adrian]

Hi,

we’ve contacted our supplier to get fae support, I really am lost as to why this isn’t working. I have used the RTC wake up on other STM32 series without any problems, but this just refuses to work.

[Jocelyn RICARD]

Hello Adrian,

I got the request from online support, so I update here to share with all.

The issue as I've seen is related to a regression in latest HAL RTC driver. A specific update was done to introduce STM32F412, and one line of code was changed for some reason:

You can see this in the code of HAL_RTCEx_SetWakeUpTimer_IT function:

__HAL_RTC_WAKEUPTIMER_EXTI_ENABLE_IT

was replaced by

__HAL_RTC_WAKEUPTIMER_EXTI_ENABLE_EVENT

So, when calling the the function HAL_PWREx_EnterSTOP2Mode you should give

PWR_STOPENTRY_WFE instead of PWR_STOPENTRY_WFI

I raised this regression to the development teams.

I'm sorry for the inconvenience.

Best regards

Jocelyn