NRF52832, RTC2 and 1 second interrupt

Question

Hello everyone, 
 I am stuck at a problem that I cannot resolve myself but I see that other people in the forum don't experience such a behaviour of their nrf52832s. 
 I want to have a 1 second timebase with RTC2 using the Nordic's SDK version: nRF5_SDK_17.0.2_d674dde. 
 I can get an interrupt at each RTC tick, but I cannot get interrupt on COMPARE0 event. Here is my code: 
 
 const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(2);

void rtc_handler(nrf_drv_rtc_int_type_t int_type){
 if (int_type == NRF_DRV_RTC_INT_COMPARE0)
 {
 nrf_gpio_pin_toggle(22); //This never gets called
 }
 else if (int_type == NRF_DRV_RTC_INT_TICK){
 nrf_gpio_pin_toggle(23); //This gets called once every 122 ms
 }
}

void lfclk_config(void){
 ret_code_t err_code = nrf_drv_clock_init();
 APP_ERROR_CHECK(err_code);

 nrf_drv_clock_lfclk_request(NULL);
}

void user_rtc_init(void){
 uint32_t err_code;

 lfclk_config();

 //Initialize RTC instance
 nrf_drv_rtc_config_t config = NRF_DRV_RTC_DEFAULT_CONFIG;
 config.prescaler = 4095;
 err_code = nrf_drv_rtc_init(&rtc, &config, rtc_handler);
 APP_ERROR_CHECK(err_code);

 //Enable tick event & interrupt
 nrf_drv_rtc_tick_enable(&rtc,true);

 //Set compare channel to trigger interrupt after COMPARE_COUNTERTIME seconds
 err_code = nrf_drv_rtc_cc_set(&rtc, 0, 1 * 8, true);
 APP_ERROR_CHECK(err_code);

 //Power on RTC instance
 nrf_drv_rtc_enable(&rtc);
} 
 
 Any help is appreciated! Thanks in advance! 
 L. B.

Sigurd · Accepted Answer

Hi, 
 Looking at the code, it should be called 1 time. But for it to trigger again, you need to do something like this in the callback. 
 static void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
 uint32_t err_code;
 if (int_type == NRF_DRV_RTC_INT_COMPARE0)
 {
 nrf_gpio_pin_toggle(COMPARE_EVENT_OUTPUT);
 //Set compare channel to trigger interrupt after COMPARE_COUNTERTIME seconds
 err_code = nrf_drv_rtc_cc_set(&rtc,0, COMPARE_COUNTERTIME*8,true);
 nrf_drv_rtc_counter_clear(&rtc);
 }
 else if (int_type == NRF_DRV_RTC_INT_TICK)
 {
 nrf_gpio_pin_toggle(TICK_EVENT_OUTPUT);
 }
} 
 Depending on your application use-case, you might want to look into using app_timer instead: https://devzone.nordicsemi.com/nordic/short-range-guides/b/software-development-kit/posts/application-timer-tutorial

NRF52832, RTC2 and 1 second interrupt

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