RTC_FLAG_WUTF is not set upon waking up from Standby mode due to the Wake-up Timer.

chai2145 · ‎2024-12-16

Hi,

I would like to identify the source of the interrupt that caused the MCU to wake up from Standby mode. To do this, I check the RTC_FLAG_WUTF and RTC_FLAG_ALRAF/RTC_FLAG_ALRBF flags after the system wakes up to determine the wake-up source. However, when the system successfully wakes up from Standby mode due to the Wake-up Timer, the RTC_FLAG_WUTF is not set and remains cleared. I also checked the RTC ISR register, where the WUTF bit remains '0'. Does anyone know why this is happening?

Amel NASRI · ‎2025-01-06

Hi @chai2145 ,

Please consider the following limitation described in STM32L0 errata sheet:

If the problem is still there even after applying the described workaround:

please make sure to use latest STM32L0 HAL/LL drivers
share a minimum example to reproduce the issue besides to the hardware details

-Amel

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