Real-time counter example for nRF9151

[Sage_Duggal]

Hello,

Is there an API or sample for the Real-Time Counter module of the nRF9151? I see the register description in the Product Specification, but I'd prefer if there was a Zephyr implementation similar to the timer API.

Motivation: The sensor sampling in nrf_cloud_multi_service uses a conventional timer which runs on the HFCLK. I'd like to alter this for my application for a low power application. As such I need to use the LFCLK.

Thank you!

[khelmutlord]

The k_timer does not actually use the HFCLK, but your kernel tick source (which is the LFCLK for the nRF9151, &rtc1). My recommendation is to use the kernel timer subsystem in Zephyr until you cannot anymore, i.e. you need PPI w/ a timer or need more exact timing than the Zephyr kernel permits.

Otherwise, it's possible to use the Zephyr counter interface or nrfx APIs.

https://docs.zephyrproject.org/apidoc/latest/group__counter__interface.html

Using a nodelabel, timer0-timer2

https://github.com/zephyrproject-rtos/zephyr/blob/3973aaa282c88f7a2a6a4600fc6f896efec589c2/dts/arm/nordic/nrf91_peripherals.dtsi#L379

For nrfx:

github.com/.../timer

[Sage_Duggal]

Interesting! So how does that square with this section of the documentation that talks about how the general purpose timer uses the HFCLK?

I figured k_timer was using the timer peripheral linked in this comment, and not the real time counter.