STM32H743 LP timers

[alan32]

Hi Forum,

I am using the stm32H743 and trying to keep the power consumption as low as possible by entering sleep or stop mode. I am then using a lptimer  to wake the device. Eventually, I will also use the timer to determine how long the device is asleep for.  I have been using stm32cubeIDE/MX  to develop with. 

When I use LPTIM1 this all works fine and the device is woken from sleep or stop mode.

However, I have tried to move across to LPTIM5 and the device will wake from sleep mode, but will not wake from stop mode.

From what I can see in the RM all the LPTIMERS can wake the device from stop mode, but just want to check that I haven't missed something.

A couple of snippets below.. 

 

HAL_LPTIM_Counter_Start_IT(&hlptim5, 300); //300 seconds timer

// HAL_LPTIM_Counter_Start_IT(&hlptim1, 300);

 

HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);

//HAL_PWR_EnterSLEEPMode(PWR_LOWPOWERREGULATOR_ON, PWR_SLEEPENTRY_WFI);

 

Many thanks

Alan

[Amel NASRI]

Hi @alan32 ,

 

Please make sure that you are not facing the limitation  "Device may remain stuck in LPTIM interrupt when entering Stop mode" described in the errata sheet .

You can apply the suggested workaround to prevent it.

-Amel