How to toggle the GPIO sense field?

[Robert Blasutig]

So now that I understand the problem with overlapping asserted events on the GPIO port, I can't figure out the correct way to reset the sense field in the GPIOTE_IRQHandler correctly.

I have initialized a couple of input pins like so:

NRF_GPIO->PIN_CNF[PIN_GPIO_REED2] = 
    (GPIO_PIN_CNF_SENSE_Low << GPIO_PIN_CNF_SENSE_Pos)
    | (NRF_GPIO_PIN_PULLUP << GPIO_PIN_CNF_PULL_Pos)
    | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
    | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);    
	
NRF_GPIO->PIN_CNF[PIN_GPIO_REED1] = 
    (GPIO_PIN_CNF_SENSE_Low << GPIO_PIN_CNF_SENSE_Pos)
    | (NRF_GPIO_PIN_PULLUP << GPIO_PIN_CNF_PULL_Pos)
    | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
    | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);

And the interrupt handler is

void GPIOTE_IRQHandler(void)
{
    if (NRF_GPIOTE->EVENTS_PORT != 0) {
        NRF_GPIOTE->EVENTS_PORT = 0;
		
	if (!nrf_gpio_pin_read(PIN_GPIO_REED1))
	{
	    //first reed switch activated - do stuff
	}
	if (!nrf_gpio_pin_read(PIN_GPIO_REED2))
	{
	    //second reed switch activated - do other stuff
	}
		
	//I lose events if these assertions overlap
    }
}

What additions are necessary to properly toggle the sense field so that the overlapping assertions don't result in lost events?

I don't understand under what conditions each pin's sense value should be toggled appropriately.

[Robert Blasutig]

For those of us that don't think the solution is immediately obvious, I'll share some code that seems to get it to behave...

This is for a single IO. The app_gpiote code has more clever stuff that doesn't really make clear what needs to be done... at least to me. I guess an explanation is that overlapping GPIO port events cannot occur if the current pin level is the same as the current sense setting.

[Robert Blasutig]

volatile bool reed2asserted = false;
void GPIOTE_IRQHandler(void)
{
  if (NRF_GPIOTE->EVENTS_PORT != 0)
  {
    NRF_GPIOTE->EVENTS_PORT = 0;
	
    if (nrf_gpio_pin_read(PIN_GPIO_REED2) && reed2asserted)
    {
      nrf_gpio_pin_toggle(LED1);
      reed2asserted = !reed2asserted;
      NRF_GPIO->PIN_CNF[PIN_GPIO_REED2] = 
        (GPIO_PIN_CNF_SENSE_Low << GPIO_PIN_CNF_SENSE_Pos)
        | (NRF_GPIO_PIN_PULLUP << GPIO_PIN_CNF_PULL_Pos)
        | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
        | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);    
    }
    else if (!nrf_gpio_pin_read(PIN_GPIO_REED2) && !reed2asserted)
    {
      nrf_gpio_pin_toggle(LED1);
      reed2asserted = !reed2asserted;
      NRF_GPIO->PIN_CNF[PIN_GPIO_REED2] = 
        (GPIO_PIN_CNF_SENSE_High << GPIO_PIN_CNF_SENSE_Pos)
        | (NRF_GPIO_PIN_PULLUP << GPIO_PIN_CNF_PULL_Pos)
        | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
        | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);    
    }
  }
}