Issue with rtc in nrf52840

Question

Hi i am using nRF52840 with segger embedded studio. 
 SDK -> nrf5-sdk 17.1.0 I want to configure rtc2 so that whenver i initialize it it should generate an interrupt after certain interval and wakeup the system. 
 B_LED_RED is blinking but B_LED_BLUE is not blinking. 
 // RTC instance for RTC2
const nrfx_rtc_t rtc = NRFX_RTC_INSTANCE(2);
nrfx_rtc_config_t rtc_cfg = NRFX_RTC_DEFAULT_CONFIG;

// RTC wake-up handler
void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
if (int_type == NRFX_RTC_INT_TICK)
{

nrf_gpio_pin_toggle(B_LED_RED);
}

else if(int_type == NRFX_RTC_INT_COMPARE0)
{
nrf_gpio_pin_toggle(B_LED_BLUE);

}
}

void rtc_init(void)
{
rtc_cfg.prescaler = 4095; //1 tick 32768/(4095+1) = 8 Hz= 125ms/tick

uint32_t err_code;

err_code = nrfx_rtc_init(&rtc, &rtc_cfg, rtc_handler);
APP_ERROR_CHECK(err_code);

nrfx_rtc_tick_enable(&rtc, true);

nrfx_rtc_cc_set(&rtc, 0, 8, true);

nrfx_rtc_enable(&rtc);

}

Hung Bui · Accepted Answer

Hi Sumit, 
 How do you expect B_LED_BLUE to blink ? The CC counter is not re-occuring, it's only triggered when the counter goes from N-1 to N (where N is what set in the CC[] register) 
 So you either have to change the CC counter to the future (next 8 seconds, take care of the wrap around) or you should reset the COUNTER if you want it to be triggered again. 
 By default the nrfx_rtc driver will disable and clear the CC counter, so you won't see the event occur when COUNTER is overflow :

Issue with rtc in nrf52840

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