RTC overflw handler

Question

Hello , I am working on the development kit nrf52, i want to know how i canget the value of the RTC overflw and then how i can reset the RTC to zero. 
 thank you in advance Best regards

Susheel Nuguru · Answer

You cannot get the overflow value but you can get an overflow event in EVENTS_OVERFLW register. For this you have to enable this event in RTC->EVTEN register. 
 You then need to enable interrupt for this in the INTENSET and increment a static variable everytime you get the overflow event. After incrementing the variable, you clear the overflow event. 
 for example in the RTC interrupt handler you can do something like this 
 static uint8_t tick_overflow_count = 0;
 /* check for overflow in RTC counter */
 if(nrf_rtc_event_pending(portNRF_RTC_REG, NRF_RTC_EVENT_OVERFLOW))
 {
 nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_OVERFLOW);
 tick_overflow_count++;
 }
 
 // then you get the full value
 uint32_t systick_counter = nrf_rtc_counter_get(portNRF_RTC_REG);
 full_value = ((tick_overflow_count << portNRF_RTC_BITWIDTH) + systick_counter);

RTC overflw handler

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