Wakeup from RTC only

RE: Wakeup from RTC only

ovrebekk — Mon, 12 Oct 2020 14:38:44 GMT

Hi Brian

The code you sent should work fine, as long as the RTC event register is not cleared anywhere else.

Best regards
Torbjørn

RE: Wakeup from RTC only

bfriedk1 — Sun, 11 Oct 2020 15:04:35 GMT

Torbjørn -

Thank you for the reply. I noticed that the SDK RTC example shows how to specify an interrupt handler and reworked our code to use that technique. That worked well, but fails when I power off all the RAM, even when I store the RTC instance in one retained section of RAM.

The code I originally shared works when powering off RAM, so I looked for another way to know if the interrupt triggered corresponds to the RTC. This seems to work:

do {
	__WFE();
} while (!nrf_rtc_event_pending(portNRF_RTC_REG, NRF_RTC_EVENT_COMPARE_0));

My hope is that the (inlined) function returns true when the counter compare interrupt fires. Would you agree?

Regards,

Brian

RE: Wakeup from RTC only

ovrebekk — Thu, 08 Oct 2020 12:54:56 GMT

Using __WFE() or sd_app_evt_wait() will wake you up on any interrupt that occurs, assuming that interrupt is enabled through the interrupt controller, that is correct.

The normal way to handle this is to implement the interrupt handler, and set a flag or run some other code there. Then you can check this flag in your while loop, and only exit when the flag is set.

Best regards
Torbjørn