RTC with PPI, interrupts stops after two events

RE: RTC with PPI, interrupts stops after two events

Sigurd — Fri, 07 Feb 2025 12:13:08 GMT

Hi!

The zephyr kernel timer uses RTC. Set it up to get trigger callback every 1 second, and start the sampling in the callback.

RE: RTC with PPI, interrupts stops after two events

Ros — Fri, 07 Feb 2025 02:41:34 GMT

[quote userid="15146" url="~/f/nordic-q-a/118685/rtc-with-ppi-interrupts-stops-after-two-events/521832"]I would recommend using a kernel timer for this instead.[/quote]

This is a low-power application, so I wish not wake-up cpu before ADC sampling completes.

RE: RTC with PPI, interrupts stops after two events

Sigurd — Thu, 06 Feb 2025 23:51:49 GMT

Hi,

I would recommend using a kernel timer for this instead.

https://docs.zephyrproject.org/latest/kernel/services/timing/timers.html#using-a-timer-expiry-function

void my_work_handler(struct k_work *work)
{
    /* do the processing that needs to be done periodically */
    ...
}

K_WORK_DEFINE(my_work, my_work_handler);

void my_timer_handler(struct k_timer *dummy)
{
    k_work_submit(&my_work);
}

K_TIMER_DEFINE(my_timer, my_timer_handler, NULL);

...

/* start a periodic timer that expires once every second */
k_timer_start(&my_timer, K_SECONDS(1), K_SECONDS(1));

RE: RTC with PPI, interrupts stops after two events

Ros — Thu, 06 Feb 2025 20:24:06 GMT

I'm using nRF52840.

RE: RTC with PPI, interrupts stops after two events

Sigurd — Thu, 06 Feb 2025 16:52:36 GMT

Hi!

[quote userid="85556" url="~/f/nordic-q-a/118685/rtc-with-ppi-interrupts-stops-after-two-events"]Since my intention is to use this to trigger an ADC at 1 Hz[/quote]

What chip are you using? I see you have a nRF52820 tag, but the nRF52820 does not have ADC.

https://docs.nordicsemi.com/bundle/struct_nrf52/page/struct/nrf52.html