STM32L442KC, shutdown mode and RTC alarm to wake-up?

[frank.zhao]

The datasheet says that shutdown mode while RTC is running (via external crystal, aka LSE) is definitely available. I need to wake up at exactly midnight once per day, hopefully for several years.

If I understand correctly, the shutdown mode allows wake-up from the wake-up GPIOs, and the "internal wake-up line".

The RTC has AlarmA, AlarmB, and a "WakeUpTimer".

My question is: is "AlarmA" capable of waking up from shutdown mode via the "internal wake-up line"? (EXTI line 18)

The datasheet says "All RTC events (Alarm, WakeUp Timer, Timestamp or Tamper) can generate an interrupt and wakeup the device from the low-power modes.", so my own guess is yes, AlarmA is capable of waking up from shutdown mode.

I am asking because the WakeUp Timer nomenclature sort of makes me think AlarmA and AlarmB will not work in shutdown mode. None of the examples provided from ST cover my particular use case. So I am simply making sure by asking here.

Thank you

[Mohamed Aymen HZAMI]

Hello frank,

For more information on shutdown mode, you can refer to the online training session (Power controller) :

• https://www.st.com/content/st_com/en/support/learning/stm32-education/stm32l4-online-training.html

Best Regards,

Mohamed Aymen.

[David.Sorber]

I have the exact same question that was posed above. The datasheet for the STM32L4S9VI suggests that RTC AlarmA can be used to wake the device from Shutdown mode. However, I have been unable to get this to work and I cannot find any examples that demonstrate this usage. The training resource provides more information about the power controller but doesn't answer the question.

Can someone please 1) confirm that is it possible to wakeup from shutdown mode using RTC AlarmA and 2) if it is possible, provide an example or instructions on how to make it work.

Thanks.

[David.Sorber]

I have the exact same question that was posed above. The datasheet for the STM32L4S9VI suggests that RTC AlarmA can be used to wake the device from Shutdown mode. However, I have been unable to get this to work and I cannot find any examples that demonstrate this usage. The training resource provides more information about the power controller but doesn't answer the question.

Can someone please 1) confirm that is it possible to wakeup from shutdown mode using RTC AlarmA and 2) if it is possible, provide an example or instructions on how to make it work.

Thanks.

[AD.1]

+1 can anyone provide an answer to this,

We need clarification on the following:

Can the device be woken up from shutdown with the following:

AlarmA ?

AlarmB ?

Wakeup Timer ?

WakeUp Timer ?

Timestamp ?

Tamper ?