MCU wakeup from sleep by a timer

[enkavak]

Hello,

       I am using nRF52832 IC with softdevice and SDK v15.

       I wish to make the MCU in sleep mode and then a couple of milliseconds (let's say 250ms) wakes up the MCU. For this purpose, can I use the timer? Or do you have any idea ?

       

[haakonsh]

You'll want to use the RTC — Real-time counter. See the Real Time Counter Example and RTC API documentation. 

[enkavak]

Can I use it with the softdevice?

I have external xtal. Do I need to use "lfclk"?

In addition, does the resolution is second? I need resolution in milliseconds 

[haakonsh]

What is the state of the RTC2's register after you've configured, enabled, and started it?

[enkavak]

yes, enabled and started.

[haakonsh]

I need the content of the RTC2's registers...

[enkavak]

When it is running

When It goes to sleep

[haakonsh]

With a prescaler value of 4095dec you will get an RTC frequency of 8Hz (32768Hz / PRESCALER + 1), and with a compare value of 100 000dec you will not trigger an event until 3,5 hours (100 000 ticks/ 8Hz * 60s * 60m) have passed...

[enkavak]

100.000 was an old trial number. even if I write 8 as the value, MCU never wakes up.

[haakonsh]

Turn off the RTC tick event and interrupt, then read out the content of the register again if it still does not work.

[enkavak]

No, I does not work.