How can the MP1 M4 Core be woken up by an LPTimer in STOP mode?

DHöni.1 · ‎2022-01-11

I have built a test program from the two examples PWR_STOP_CoPro and LPTIM_PulseCounter. With the LPTIM_PulseCounter I changed the CounterSource to LPTIM_COUNTERSOURCE_INTERNAL and adjusted the priority HAL_NVIC_SetPriority (LPTIM2_IRQn, 0, 0);

Both programs run as expected only when I start the timer HAL_LPTIM_TimeOut_Start_IT (& hlptim2, 0xFFFF, 0x7000) and then go to STOP Mode HAL_PWR_EnterSTOPMode (PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI); the M4 core does not wake up by the LP Timer interrupt, but an EXTI interrupt lets it wake up.

Can someone tell me what I might have overlooked?

Olivier GALLIEN · ‎2022-01-14

Hi @Dirk Höning ,

As per stipulated in Ref man and in wiki Coprocessor power management - stm32mpu wakeup can only be done with EXTI.

EXTI mapped to the LPTIM instance is defined in Linux Device Tree.

Olivier

Olivier GALLIEN
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DHöni.1 · ‎2022-01-21

Hi Olivier,

thanks for the reply. It is hard for us to figure out how to map the LPTIM to the EXTI events in the Device-Tree. Could you provide an example for this configuration?

Best regards

Dirk