Timer confusion

Question

So the nRF51822 has one 32 bit, two 16 bit timers and two Real Time Counters. 
 
 
 What is the difference in a timer and counter? The timer API seems to hard link RTC1 to the timer API. 
 
 
 Can we choose which timer to use or is it abstracted by the API.

Håkon Alseth · Accepted Answer

Hi, 
 
 
 A timer usually holds different modes. "Counter mode" is one of these modes.
What we do is that we have a Capture/Compare mode, and we emulate a counter mode by making the timer reset itself using "SHORTS" register. 
 
 
 You can setup any timer for the purpose you'd like. If you need good resolution, use TIMER0/1/2 (16 MHz based with prescaling options).
If you need a low power timer, use the RTC (32 kHz based) 
 
 
 We also provide a timer library. The "app_timer" library uses the 32 kHz RTC. 
 Note: If you are using the S110 stack, please see the softdevice specification to see which peripherals are blocked. 
 Best regards
Håkon