Please share or let me know what is the best solution for a long timer ( 2 to 4 Hours) interrupt example(s)

[davidle.ee9]

I want to set up the interrupt for system power off the main MCU, the STM32L4 xx .

As soon it is powered on, then starting the timer to turn it off after 2- to- 4 Hours.

Please point me how to implement it since I'm still new for STM32L4xx

[S.Ma]

You probably have to look at RTC with alarms as the duration required here is quite long.

Otherwise, use the LPTIM which should have its own clock local source

[davidle.ee9]

Thanks

But I'm in using its internal RC as the system clock (no external X-tal )

Could it be OK for your idea?

[Peter Mather]

the 32-bit Timer2 with a 16-bit prescaler set will easily meet your requirement

[S.Ma]

On stm32l4 most peripherals can run with their own chosen clock source... For optimum power saving. Checkout the LPTIMER