Custom timer in nRF secure bootloader

[Louis_263]

Hi,

I would like to introduce a timer in my nRF secure bootloader that calls a function and toggles an LED every 2 seconds. I already know that several timers are used by the secure bootloader and therefore wanted to ask which custom application timers I can use without causing collisions.

BR

Louis

[ovrebekk]

Hi Louis

For clarity, do you want to use an app_timer, or a dedicated TIMER or RTC peripheral?

If the app_timer library is used you can assign as many timers as you want, only limited by available memory. 

Using a dedicated TIMER or RTC module is also an option, but then you are limited to the number of hardware peripherals available. 

If you are using the nRF52820 you should be able to use TIMER2, TIMER3 or RTC2 if you want. 

Best regards
Torbjørn

[Louis_263]

Hi Torbjorn,
thanks for your answer.
I think that using the app_timer library takes the most flash memory, right? I would like to choose the method that takes up less memory, so probably one of the hardware timers.

BR

Louis

[Jared]

Hi,

The app timer is based on the RTC1 peripheral. The difference between RTC and TIMER is the that the latter is based on the more accurate HCLK vs the former which is based on the LFCLK. The former draws significantly more current as well. 

regards

Jared