RE: TIMERS IN NRF5340

Simon — Thu, 29 Apr 2021 22:34:13 GMT

RTC peripheral

The k_timer_start() will actually use the RTC peripheral, in the following manner:

k_timer_start() | zephyr/include/kernel.h
- z_impl_k_timer_start() | zephyr/kernel/timer.c
  - z_add_timeout() | zephyr/kernel/timeout.c
    - z_clock_set_timeout() | drivers/timer/nrf_rtc_timer.c
      - Uses functions from nrf_rtc.h

By default CONFIG_NRF_RTC_TIMER will be equal to y (check <sample>/build/zephyr/.config), which will make it use the RTC. I think you can use a systick timer by enabling CONFIG_CORTEX_M_SYSTICK. However, RTC is probably the best choice between these: https://devzone.nordicsemi.com/f/nordic-q-a/21067/nrf52-use-systick-or-rtc/82317#82317.

Timer peripheral

Check out the sample zephyr/samples/drivers/counter/alarm to see how to use the counter API.

If you're wondering if you should use the TIMER or the RTC, I would recommend you to read the following: https://devzone.nordicsemi.com/f/nordic-q-a/12731/clocks-timers-rtc-why/48338#48338. It was written a long time ago for a different chip and SDK, but should be somewhat relevant still

Best regards,

Simon

SRINI — Thu, 29 Apr 2021 13:32:40 GMT

Hi Simon,

Thanks for your reply.

It seems to be zephyr based kernel timers API (soft timers) in the ADC code. can I get hardware based timer example code?

Thanks & Regards,

Srinivas.

Simon — Thu, 29 Apr 2021 11:19:03 GMT

Take a look at the NCS tutorial, section 3.5 Add the ADC peripheral, which provides a sample using a timer. It may be useful to complete 3.2 Set it up, 3.3 Build and flash it and 3.4 Modify the device tree first.