Using more than 4 buttons with GPIOTE interrupts

Question

Hi,

I am using GPIOTE interrupts to detect button presses. It works fine but there are only four channels in GPIOTE->EVENTS_IN[] and each channel can only be assigned to one pin. How should I do if I want to implement more than 4 buttons?

Basically I set up GPIOTE like this:

  pinInput(pin); // make sure the pin is set as input
  NRF_GPIOTE->CONFIG[channel] = (static_cast<uint32_t>(transitionMode) << GPIOTE_CONFIG_POLARITY_Pos) |
      (pin << GPIOTE_CONFIG_PSEL_Pos) |
      (GPIOTE_CONFIG_MODE_Event << GPIOTE_CONFIG_MODE_Pos);
  NRF_GPIOTE->INTENSET = GPIOTE_INTENSET_IN0_Set << channel; // @warning: we should use bitfields instead
  NRF_GPIOTE->EVENTS_IN[channel] = 0;

and in the GPIOTE_IRQHandler I check which channel has been interrupted and send an appropriate callback.

I do not use any sd by the way.

Thanks!

Susheel Nuguru · Accepted Answer

instead of using GPIOTE channels use GPIOTE->PORT event, then you can have 31 buttons ..
There are lot of examples for this. In GPIOTE_IRQHandler, you have to remember previous pin state to see which pin has changed state.

Using more than 4 buttons with GPIOTE interrupts

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