Not sure if understand APP_TIMER_TICKS macro.

RE: Not sure if understand APP_TIMER_TICKS macro.

Nabil — Tue, 25 Apr 2017 10:56:37 GMT

Hello,

I have read that but I don't understand.

The minimum resolution is 1 ms ?

Solved :

with PRESCALER of 22 I can have 39.2 uS

RE: Not sure if understand APP_TIMER_TICKS macro.

Susheel Nuguru — Tue, 25 Apr 2017 10:54:11 GMT

You need to configure app_timer with atleast 5 RTC ticks minimum . With 1 tick about 30.5uS, the minimum you can use with app_timer is 153uS.

RE: Not sure if understand APP_TIMER_TICKS macro.

Nabil — Tue, 25 Apr 2017 10:13:43 GMT

Hello,

Is it possible to configure the timer for 100 uS with APP_TIMER?

Thank you

RE: Not sure if understand APP_TIMER_TICKS macro.

lee.W — Wed, 27 Jul 2016 09:31:53 GMT

I couldn't even find the include file to use this macro so your doing better than me already!

RE: Not sure if understand APP_TIMER_TICKS macro.

Ina — Tue, 15 Sep 2015 08:16:07 GMT

Thank You very much for quick and detailed answer, it really helped me! Regards, Ina

RE: Not sure if understand APP_TIMER_TICKS macro.

Susheel Nuguru — Tue, 15 Sep 2015 07:36:43 GMT

APP_TIMER is running with frequency 32768 Hz.

This means that with prescaler 0, it will generate 32768 ticks per second.

Since the app_timer_start function arguments needs the time in ticks and not in millisecond, we need to convert the interval in ms after which you need your timer_callback to be called into app_timer ticks.

This can be done using APP_TIMER_TICKS(X,Y)

500Hz sampling means that you you need one sample every 1/500 = 2ms, so to convert this sampling interval into app_timer ticks you need

APP_TIMER_TICKS(2, APP_TIMER_PRESCALER)

20Hz sampling means that you you need one sample every 1/20= 50ms, so to convert this sampling interval into app_timer into ticks you need

APP_TIMER_TICKS(50, APP_TIMER_PRESCALER)

So yes, you got it right :)