App timer prescaler

RE: App timer prescaler

Susheel Nuguru — Tue, 01 Sep 2015 09:52:27 GMT

Just an addition to RK answer APP_Timer is 24 bit. The number you mentioned 58982400(0X3840000) does not fit, trying to write it will write (0X840000) which is 8650752 timer ticks. With prescaler 0 each tick is 30.516us. So like RK mentioned you will end of with 264 second timer.

If you change the prescaler say to 7, then there are 4096 ticks per seconds and 7372800(0X7080000) ticks for 30 minutes. This should fit into the timer well.

RE: App timer prescaler

RK — Tue, 01 Sep 2015 00:38:47 GMT

no it'll give you a 264 second timer. Everything internally is '&' with the maximum timer count which is 0x00FFFFFF so you'll end up with 58982400 mod 16777216 timer ticks.

RE: App timer prescaler

FormerMember — Mon, 31 Aug 2015 23:30:29 GMT

Sorry, my bad. 512 seconds is max with 0 prescalar. You need a prescalar of 3 so that LFCLK is divided by 4, which will give enough to count for 30 min. I've to sleep soon I guess. ;)

RE: App timer prescaler

Chris — Mon, 31 Aug 2015 23:20:11 GMT

By yes, do you mean I will get a 30 minute timer? Or that 512 seconds is the max and anything above that could be unpredictable?

Yes, I forgot to include that I call app_timer_create. I mean, the program works, but I have not sat down and actually timed anything longer than 512 seconds.

RE: App timer prescaler

FormerMember — Mon, 31 Aug 2015 22:53:30 GMT

Yes. I hope you call app_timer_create to create timer_id.