I want to wakeup from standby-mode in less than 20msec.

YTaka.1 · ‎2020-08-28

I want to wake up from standby-mode in less than 20 seconds using Periodic auto-wakeup, but I can't wake up below 22 msec.

Could you tell me if there is any good way?

The following HAL driver is used.

HAL_RTCEx_SetWakeUpTimer( & hrtc,1,RTC_WAKEUPCLOCK_RTCCLK_DIV2 );

And the MCU is STM32L433.

Thanks in advance!

M.Hajji · ‎2020-08-29

Hello YTaka.1

First make sure your LSE/RTC is well calibrated, you can use the 1Hz RTC_output to be sure of that.

In RM0394 section 36.3.6 Periodic auto-wakeup, it say "When the periodic wakeup interrupt is enabled by setting the WUTIE bit in the RTC_CR register, it can exit the device from low-power modes." So I guess give HAL_RTCEx_SetWakeUpTimer_IT a try.

I suggest also to test, without entering the standby mode, the time between two wakeup event by the RTC, just to better understand how your system behave.

Good luck,

Regards,

Hajji.