How to start and stop a timer in S110?

[Ricky]

I use NRF51822 and s110. I want to know how to start and stop a timer, to get the time that the timer run. whitch API should I use int S110?

[Nikita]

You can get current timer value by triggering CAPTURE task for any Capture/Compare register.

NRF_TIMER2->TASKS_CAPTURE[1] = 1; // trigger TASKS_CAPTURE for Capture/Compare register 1.
time = NRF_TIMER2->CC[1]; // Get current timer value

[Ricky]

I want to init a timer by using APP_TIMER_INIT(APP_TIMER_PRESCALER, 2, 4, true); but if I set APP_TIMER_PRESCALER to 0, how many ticks equal to 1s ?

[Nikita]

There is macro function for this:

#define APP_TIMER_TICKS(MS, PRESCALER)\
            ((uint32_t)ROUNDED_DIV((MS) * (uint64_t)APP_TIMER_CLOCK_FREQ, ((PRESCALER) + 1) * 1000))

It'll be 32768 ticks.

[Ricky]

thank you!