RTC0 nrf 52 read counter value

RE: RTC0 nrf 52 read counter value

Vishnu Pradeep — Tue, 01 Nov 2016 13:52:50 GMT

Hi Ankush, could you post the rtc initialization?

RE: RTC0 nrf 52 read counter value

Ankush — Thu, 07 Jul 2016 15:38:59 GMT

Hi,

i am able to read the value of counter by using

count = NRF_RTC0->COUNTER;

Thanks for your support!!

RE: RTC0 nrf 52 read counter value

RK — Wed, 06 Jul 2016 11:18:39 GMT

You probably haven't started a Low Frequency Clock, without one of those started, the counter doesn't count. You can start the RC one (pretty inaccurate) or the XTAL one (if there's a crystal mounted) which is more accurate. However, you have to start some LF clock.

Usually this is taken care of by the softdevice initialisation as that needs an LF clock source, however if you're not using a softdevice, ie no bluetooth, then nothing else is running one.

RE: RTC0 nrf 52 read counter value

Ankush — Wed, 06 Jul 2016 10:59:47 GMT

Hi Terje,

Actually I am using nrf_rtc_counter_get() function for getting the counter value but it is showing only one value when i print on UART terminal. these are the statements i am using

         nrf_drv_rtc_t const *const    p_instance;
         temp=nrf_drv_rtc_counter_get   (p_instance)    ;
         printf("current value is=%d\r\n",temp);

is it the right way ??

RE: RTC0 nrf 52 read counter value

tesc — Wed, 06 Jul 2016 10:25:53 GMT

Sorry, I missed the point. See the RTC HAL and driver, in particular RTC HAL and nrf_rtc_counter_get().

RE: RTC0 nrf 52 read counter value

Ankush — Wed, 06 Jul 2016 09:58:44 GMT

thanks Terje for your reply.

Do you have any idea how can I read the value of real time counter in nrf52?

RE: RTC0 nrf 52 read counter value

tesc — Wed, 06 Jul 2016 09:41:28 GMT

Hi,

First I must stress that the real time counter (RTC) is a timer. It is not, as the abbreviation "RTC" may suggest, a real time clock. However, it runs off the 32 kHz clock and can be used to keep track of time within the accuracy of that clock signal.

You will find that the Real Time Counter Example of the latest SDK uses RTC on the nRF52.

For date and time calculation I suggest that you use an existing time and date library, since there are a lot of pitfalls when working with time and date. I think the ctime standard c library would be a good choice. Most likely the time_t format will be a unix timestamp and it should be safe to increment a "current time" value of this type every second to keep it up to date.

Regards, Terje

RE: RTC0 nrf 52 read counter value

Ankush — Wed, 06 Jul 2016 09:16:08 GMT

I am using following instructions to read current value

              nrf_drv_rtc_t const *const 	p_instance;
             temp=nrf_drv_rtc_counter_get	(p_instance)	;
	printf("current value is=%d\r\n",temp);

Is it the right way to read value? I am getting only one value. here it is not updating.