APP_TIMER and RTC1 Interrupt

[superpak]

SDK 14.2.

Application Timer Library

I had a question regarding the Application Timer library and the way it checks for timeout handlers. In the documentation, it says:

"Checking for time-outs and invoking the user time-out handlers is performed in the RTC1 interrupt handler."

How often does the RTC1 interrupt occur? What decides how often this RTC1 interrupt occurs? And if it occurs too often, would that not consume more power? If I have a prescaler of 255, does this mean the RTC1 interrupt would fire every 7812.5 μs and check for timeouts? 

Thanks.

[Einar Thorsrud]

Hi,

The Application Timer library does not wake up regularly like you suggest. It calculates the amount of ticks until it should wake up and sets the COMPARE register accordingly. This is recalculated and configured every time it wakes up if necessary, so there are no additional interrupts. You can refer to the implementation in app_timer.c if you want all the details.