RTC overflw handler

RE: RTC overflw handler

Susheel Nuguru — Mon, 19 Mar 2018 14:11:23 GMT

1) enable the overflow event and interrupt

nrf_drv_rtc_overflow_enable

You forgot to clear the even in RTC2 ISR, but that cannot be the reason for the system not to go to deep sleep. Also move the printf to the start of the condition.

if(NRF_RTC2->EVENTS_OVRFLW==1)
{

printf("overflw");

NRF_RTC2->EVENTS_OVRFLW = 0;
NRF_RTC2->TASKS_CLEAR = 1;
sd_power_system_off();
}

This is very basic thing to work. Please look at the SDK examples to see how this things work

RE: RTC overflw handler

Nero — Mon, 19 Mar 2018 14:00:17 GMT

thanks ,

I initialised the RTC 2 (const nrf_drv_rtc_t rtc1 = NRF_DRV_RTC_INSTANCE(2); /**< Declaring an instance of nrf_drv_rtc for RTC2. */)

the problem is the system does not go into sleep mode

RE: RTC overflw handler

Susheel Nuguru — Mon, 19 Mar 2018 13:53:34 GMT

1) You are initializing RTC1 and checking for RTC2 events in ISR. You need to check RTC1 events in ISR.

 if(NRF_RTC2->EVENTS_OVRFLW==1)
  {
		   NRF_RTC2->TASKS_CLEAR		= 1;
		   sd_power_system_off();
			printf("overflw");
}

printf will never be executed since the sd_power_system_off will never return. Any wakeup will reset the chip. If you want to return here, then use sd_app_evt_wait() instead of system off.

RE: RTC overflw handler

Nero — Mon, 19 Mar 2018 13:07:31 GMT

I initialised the rtc2 , just i use the name rtc1

RE: RTC overflw handler

butch — Mon, 19 Mar 2018 12:49:53 GMT

rtc1 OR rtc2? Your code seems to initialize rtc1 but looks for an event on rtc2.

RE: RTC overflw handler

Nero — Mon, 19 Mar 2018 11:04:56 GMT

RE: RTC overflw handler

Susheel Nuguru — Mon, 19 Mar 2018 10:51:39 GMT

The only way you can do it is in the RTC ISR_handler. There is no shortcut in hardware to do this automatically.

RE: RTC overflw handler

Nero — Mon, 19 Mar 2018 10:45:38 GMT

Thank ou Mr Aryan

there are any possibility to activate the sleep mode by an rtc overflow event?

RE: RTC overflw handler

Susheel Nuguru — Fri, 16 Mar 2018 11:51:21 GMT

you need to convert the accelerometer interrupt to event by connecting it to GPIOTE in event mode
Connect the output of this event to PPI and convert it to a TASK
Connect this TASK to RTC->TASKS_CLEAR

This will reset the RTC counter to zero everytime you have any interrupt from accelerometer.

To know more about how to configure GPIOTE and PPI for this, you need to look at their SDK examples in SDK\examples\peripheral and read the docs about them.

RE: RTC overflw handler

Nero — Fri, 16 Mar 2018 09:45:11 GMT

Hello Aryan ,

Thank you for respond.

I want to reset the rtc by a extern interruption (accelerometer), i want to know which function can i use?

Thank you in advance.

RE: RTC overflw handler

Susheel Nuguru — Wed, 14 Mar 2018 14:04:41 GMT

You cannot get the overflow value but you can get an overflow event in EVENTS_OVERFLW register. For this you have to enable this event in RTC->EVTEN register.

You then need to enable interrupt for this in the INTENSET and increment a static variable everytime you get the overflow event. After incrementing the variable, you clear the overflow event.

for example in the RTC interrupt handler you can do something like this

    static uint8_t tick_overflow_count = 0;
    /* check for overflow in RTC counter */
    if(nrf_rtc_event_pending(portNRF_RTC_REG, NRF_RTC_EVENT_OVERFLOW))
    {
        nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_OVERFLOW);
        tick_overflow_count++;
    }
    
    // then you get the full value
    uint32_t systick_counter = nrf_rtc_counter_get(portNRF_RTC_REG);
    full_value = ((tick_overflow_count << portNRF_RTC_BITWIDTH) + systick_counter);