Milliseconds since startup?

RE: Milliseconds since startup?

Matthias P. — Tue, 24 Nov 2015 08:59:21 GMT

Ok, I got it now. It's

ticks * ( (APP_TIMER_PRESCALER + 1 ) * 1000 ) / APP_TIMER_CLOCK_FREQ;

RE: Milliseconds since startup?

Matthias P. — Tue, 24 Nov 2015 07:52:09 GMT

Coudl you please give me a hint on how to convert the ticks into milliseconds?

RE: Milliseconds since startup?

Torsten Robitzki — Mon, 23 Nov 2015 13:02:16 GMT

Hi Matthias, when the interrupt fires, your timer still runs and the interrupt will fire again, when the 16 bit timer overflows and reaches 125 again. What you need, is to reset the timer, once your compare value of 125 was reached. I think this should be possible, by connecting the EVENT_COMPARE event with the TASK_CLR by setting the COMPARE0_CLEAR bit in the SHORTS register.

cheers, Torsten

RE: Milliseconds since startup?

Wojtek — Mon, 23 Nov 2015 12:54:04 GMT

Yes, there is simple way.

If you are using app_timer library, you can just use app_timer_cnt_get function to get RTC ticks since its startup. Just get ticks value from there, convert them to milis (according to your prescaler). Just remember that RTC overflows sometimes - app_timer_cnt_diff_compute is the best way to compute the difference, as it considers those overflows.