how to use rtc in nrf52840 dongle

RE: how to use rtc in nrf52840 dongle

calivan — Wed, 13 May 2020 11:00:33 GMT

thank you

Do you know any example I can refer to? I use nrf52840 dongle.

in your code, 'counter' isn't reset?

RE: how to use rtc in nrf52840 dongle

Kenneth — Wed, 13 May 2020 10:06:48 GMT

Typically the timeout needs to be set such that the RTC doesn't overflow, and depending on the prescaler value that may happen after 512 seconds. In your case I would have setup a timeout value of 60seconds and use a counter that increments, something like:

static uint32_t counter;

1minute_timeout_handler()
{
counter++;
if(counter%10 == 0)
10minute_timeout_handler();
if(counter%240 == 0)
4hours_timeout_handler();
}

Best regards,
Kenneth

RE: how to use rtc in nrf52840 dongle

calivan — Wed, 13 May 2020 06:41:19 GMT

If I use timer A as RTC1 and after A becomes 0 and APP-TIMER C is set to 10 seconds and counted, should I reset A when C is 0?
Is it correct that APP-TIMER uses RTC1?
Then can I use both timer A and B as RTC1?

RE: how to use rtc in nrf52840 dongle

Turbo J — Tue, 12 May 2020 09:14:52 GMT

[quote userid="89972" url="~/f/nordic-q-a/61294/how-to-use-rtc-in-nrf52840-dongle"]should I not use APP_TIMER in my case?[/quote]

Why? APP_TIMER(2) seems to be a perfect fit for your case.

Hint: You can stop timers in event handlers, e.g. one could stop timer C in the ble disconnect event.