Help, my Project can not exit the GPIO INTERRUPT HANDLER.

RE: Help, my Project can not exit the GPIO INTERRUPT HANDLER.

Ole Bauck — Mon, 07 Mar 2016 09:27:26 GMT

TASK_CLR will not affect the event, it is just not necessary.

RE: Help, my Project can not exit the GPIO INTERRUPT HANDLER.

Ole Bauck — Mon, 07 Mar 2016 09:26:28 GMT

You must configure the pin as an input and use internal pullup.

nrf_gpio_cfg_input(BUTTON_1, NRF_GPIO_PIN_PULLUP);

The input is by default disconnected and without the pullup the pin will float when the button is not pushed.

RE: Help, my Project can not exit the GPIO INTERRUPT HANDLER.

Martijn — Fri, 04 Mar 2016 07:59:56 GMT

I was just thinking, maybe the fact you are wriing to the TASK_CLR on an event configured GPIOTE channel is triggering the EVENT_IN[0] again, not really sure though. The order you do this is should also not have this effect. ;)

The tasks CLR SET and OUT are only used when the channel is set to TASK mode, not EVENT mode.

RE: Help, my Project can not exit the GPIO INTERRUPT HANDLER.

bernerd — Fri, 04 Mar 2016 07:52:10 GMT

thank you for your suggestion. and i think that the statement NRF_GPIOTE->EVENTS_IN[0] = 0; [//Event generated from pin specified in CONFIG[0].PSEL] may exit the handler? but why not?

RE: Help, my Project can not exit the GPIO INTERRUPT HANDLER.

Martijn — Fri, 04 Mar 2016 07:44:56 GMT

first of all, why don't you use the definitions provided by nordic?

second, you don't need to clear any tasks, they just run once when you write 1 to them.

thirth, in the 'migratinf from nrf51 to nrf52' document is sais the following:

Interrupt event clearing
Clearing an interrupt event may not take effect immediately.
As Cortex®
-M4F has a write buffer on the system bus, write accesses to peripherals/SRAM may be delayed.
In addition, there can be other delays in the bus infrastructure, such as bridges, that may result in writes
occurring after the store instruction has been completed.
To make sure the interrupt line is cleared before exiting an ISR, read back the given event register before
returning. Any read on the system bus will require the write buffer to be emptied first.
Existing code:

    void TIMER0_IRQHandler(void)
    {
     NRF_TIMER0->EVENTS_COMPARE[0] = 0;
    }

Required code:

    void TIMER0_IRQHandler(void)
    {
     NRF_TIMER0->EVENTS_COMPARE[0] = 0;
     (void)NRF_TIMER0->EVENTS_COMPARE[0];
    }