RE: Early wake-up from POWER/CLOCK IRQ when using RTC to wake up

bfriedk1 — Tue, 05 Jan 2021 23:12:10 GMT

Hello -

Thank you for the suggestions. The LFCLK is started at application launch when the RTC is initially configured. In our sleep function we basically reprogram the RTC for wake-up from System ON sleep after a specified period of time.

I looked at the events and enabled interrupts per your suggestion. I think I found the problem. The LFCLKSTARTED interrupt was enabled and after the __WFE() loop exits, the EVENTS_LFCLKSTARTED event was generated. To resolve that I disabled LFLCK interrupts before entering the loop:

nrf_clock_int_disable(CLOCK_INTENSET_LFCLKSTARTED_Msk);

That seems to resolve the issue and wait loop no longer exits early:

do {
  __WFE();
} while (0 == (NVIC->ISPR[0] | NVIC->ISPR[1]));

Regards,

Brian

RE: Early wake-up from POWER/CLOCK IRQ when using RTC to wake up

Jørgen Holmefjord — Tue, 05 Jan 2021 12:46:07 GMT

Hi,

Are you starting the LFCLK together with the RTC? If you are, how do you do this?

You can read out the POWER Registers and CLOCK Registers with your debugger to see which EVENTS have been generated, and which interrupts are enabled (in the INTENSET registers).

Best regards,
Jørgen