What different ways are there to automatically wake up from sleep and stop mode.

[NJong.1]

Example. The MCU should wake up automatically every 5 seconds. This is possible with the RTC.

But are there other ways to achieve this? (so not using the rtc?)

Timers don't seem to work because the clock is turned off. 

[TDK]

LPTIM works, among others. The answer will depend on your chip. All reference manuals go into detail about sleep and shutdown modes and list what is available.

[NJong.1]

I am working with the STM32L073. It looks like in stop all the clocks are off so I tought it does not work. I also tested it.

But I will try to improve the code to make it work. Thank you

[Piranha]

The sleep mode only stops a clock on CPU (state is retained). It doesn't impact peripherals at all and any interrupt wakes up the CPU.

[Mohamed Aymen HZAMI]

Hello,

To wake up the devise from low power mode there are several ways to do this :

• RTC as automatic wake up each period of time
• Using interrupts (internal or external interruptions depend on your needs).

Best Regards,

Mohamed Aymen.

[NJong.1]

I have found the solution to my problem. Thank you for the tips.

[Mohamed Aymen HZAMI]

Hello,

Good, can you please share with us your solution to this ?

Thanks and Best Regards,

Mohamed Aymen.

[NJong.1]

At first I was not sure if it was possible to keep an timer and intterupts running when de MCU goes in to sleep. But this is possible.

So its not really a solution where I can share the code.

I was hoping there was a way to wake up the MCU from stop when using a timer and interrupts, but thats not possible. Or I need to use an external interrupt or the RTC.