I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

BHAGYESH — Fri, 19 Feb 2016 07:59:10 GMT

// Internal 32kHz RC
NRF_CLOCK->LFCLKSRC = CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos;
// Start the 32 kHz clock, and wait for the start up to complete
NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
NRF_CLOCK->TASKS_LFCLKSTART = 1;
while(NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);

// Configure the RTC to run at 1 second intervals, and make sure COMPARE0 generates an interrupt (this will be the wakeup source)
NRF_RTC0->PRESCALER = 0;
NRF_RTC0->EVTENSET = RTC_EVTEN_COMPARE0_Msk; 
NRF_RTC0->INTENSET = RTC_INTENSET_COMPARE0_Msk; 
// NORDIC: Count to 32767, and not 32768
NRF_RTC0->CC[0] = 1*32767;

NVIC_EnableIRQ(RTC0_IRQn);
// NORDIC: SET IRQ PRIORITY
NVIC_SetPriority(RTC0_IRQn, 0);
        
NRF_RTC0->TASKS_START = 1;

//--------------------------------------------------------------------------------------------------

void RTC0_IRQHandler(void)
{

	  // NORDIC: CLEAR TASK AS QUICKLY AS POSSIBLE
    NRF_RTC0->TASKS_CLEAR = 1;
    // This handler will be run after wakeup from system ON (RTC wakeup)
    if(NRF_RTC0->EVENTS_COMPARE[0])
    {
			  NRF_RTC0->EVENTS_COMPARE[0] = 0;
		info.tm_sec++;
   
		}
}
//--------------------------------------------------------------------------------------------------

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

hawk — Mon, 07 Dec 2015 14:02:16 GMT

to drive the micro motor, it will use the (0.9/1 + 0.4/0)* 3ms pulse with T=15.625ms and run one step. can i use RTC or i must use TIMER of 16Mhz..??

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

hawk — Mon, 07 Dec 2015 13:53:16 GMT

i have the same question. but i must create pulse to drive the micro motor to run to simulate second/minute/hour...

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

monpetit — Mon, 07 Dec 2015 12:43:19 GMT

How about using app_timer and time.h functions?

First you can create a timer of which the period is 1000 ms. And increase global rtc counter (e.g. uint32_t rtc_counter) in the timer callback each one second. Then you can convert its format to struct tm with localtime(). You can also set rtc counter to the variable using mktime().

Of cource, rtc counter will reset if device is off and you have to set rtc counter again. =)

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

BHAGYESH — Mon, 07 Dec 2015 11:38:11 GMT

yes, like same

RE: I want to implement digital clock AND CALENDER in nRF51422 using internal RTC

monpetit — Mon, 07 Dec 2015 11:34:22 GMT

What does mean digital clock and calendar? Do you mean that nRF51422 RTC behaves as DS1307 or PCF8563?