RTC interrupt does not wake up nRF52

RE: RTC interrupt does not wake up nRF52

Stefan Birnir Sverrisson — Wed, 06 Jul 2016 14:14:06 GMT

It is also possible to configure the RTC on nRF52 with help of the nrf_drv_rtc driver. There is an example here, the saadc_low_power, that uses the nrf_drv_rtc driver and the RTC interrupt, which is working properly. Look at the rtc_config and rtc_handler functions in the example. When looking at the driver functions, I don't quickly see any specific nRF52 code there. So I would recommend to use the driver, or otherwise mimic what the driver does in order to have this working.

RE: RTC interrupt does not wake up nRF52

vik — Thu, 30 Jun 2016 14:03:04 GMT

The IRQ handler for the RTC interrupt:

void RTC1_IRQHandler (void)
{
    gu64_timerTicks += NRF_RTC1->COUNTER;
    NRF_RTC1->TASKS_CLEAR = 1;
    NRF_RTC1->EVENTS_COMPARE[0] = 0;

    if ( sd_nvic_ClearPendingIRQ (RTC1_IRQn) != NRF_SUCCESS)
    {
        NVIC_ClearPendingIRQ (RTC1_IRQn);
    }
}

The IRQ priority is defined this way for backward compatibility:

#define NRF_APP_PRIORITY_LOW (APP_IRQ_PRIORITY_LOW)

Lookin into app_util_Platform.h the priority of APP_IRQ_PRIORITY_LOW for nRF51 is 3 and for nRF52 it is 6. I also tried to set the IRQ priortiy for nRF52 to 3, but it did not solve the problem.

RE: RTC interrupt does not wake up nRF52

Anders Strand — Thu, 30 Jun 2016 12:55:52 GMT

Can you post the code snippet where you handle the RTC1_IRQn interrupts? What is the numerical value of NRF_APP_PRIORITY_LOW? The priority levels have changed between nRF51 and 52