Using LPTIM1 to wake from CSTOP mode - STM32H7

[Sde W.11]

Can LPTIM1 be used to wake the STM32H7 from CSTOPoperating mode?

From RM0455 the "RCC APB1 low-sleep clock register (RCC_APB1LLPENR" has the following bit:

However the above mentions CSLEEP, not CSTOP which is a lower power operating mode.

I think I can get the behaviour I want, timer based wakeup from CSTOP, using the RTC peripheral but for other reasons I want to do this with LPTIM1. Nothing I have tried towards this has worked.

Thanks for any and all help.

[Imen.D · Accepted solution]

Hello @Sde W.1​ ,

Let me first welcome you to the STM32 Community =)

The LPTIM can be configured to wake up the MCU from the Stop mode.

I recommend you to refer to the AN4865 : Low-power timer (LPTIM) applicative use cases on STM32 microcontrollers, in "6.3 Timeout wakeup mode" section.

You will find an applicative use case listed in this application note that clarify more this feature.

Hope my answer helped you! :smiling_face_with_smiling_eyes:

When your question is answered, please close this topic by choosing Select as Best. This will help other users find that answer faster.

Imen

[Sde W.11]

Thank you Imen DAHMEN  for your help, AN4865 was helpful. Another important point is that for the STM32H7 device I am using LPTIM1 cannot be used to wakeup the MCU from Stop2 operating mode only Stop1. I had a much easier time implementing LPTIM1 to wakeup the device when I switched to the Stop1 low power operating mode.