STM32U545 permanent RTC wakeup call

[Fizzl92]

Hello,

I am new to this cpu and experimenting with RTC wakeup using 32kHz LSE. I am usingthis code for the wakeup:

void HAL_RTCEx_WakeUpTimerEventCallback(RTC_HandleTypeDef *hrtc)

{

SystemClock_Config();

HAL_ResumeTick();

...

}

// In while(1)

HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 0x4E30, RTC_WAKEUPCLOCK_RTCCLK_DIV16, 0);

HAL_SuspendTick();

HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);

...

I removed the SetWakeUpTimer() function from MX_RTC_INIT().

It was working fine. I tweaked the MCU clock and generated the code with CubeIDE. I am not sure what went wrong but now its executing the callback (instead every 10s) instantly as fast as it can. I reverted everything i know about but still the same. Hope someone can give me a hint on what configurating i need to fix to make it work again.

[Sarra.S · Accepted solution]

Hello @Fizzl92, 

Try HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFE;

[Fizzl92]

Thank you very much! It works now with wake from Event. I did not know that RTC-wakeup is an event, not an interrupt. As in the CubeIDE calls it "RTC non-secure interrupt" i did not question it. And i think had it working once before with WFI...