GPIOTE not triggering for 2 of 5 buttons

Question

I have a custom board with 5 buttons, and a status LED, using the nrf52832_xxaa chip. 2 of the 5 buttons never trigger an interrupt. It seems like this is because nrf_gpio_pin_read always returns 0 for those 2 pins.

The pins are below:

constexpr uint32_t kButton0 = 15;
constexpr uint32_t kButton1 = 12;
constexpr uint32_t kButton2 = 7;
constexpr uint32_t kButton3 = 9;
constexpr uint32_t kResetButton = 10;
constexpr uint32_t kStatusLed = 14

Button 0-2 trigger correctly, but Button3 and Reset button never trigger. Here's how I set them up:

constexpr nrf_drv_gpiote_in_config_t kGpioteConfig = {
  sense : NRF_GPIOTE_POLARITY_HITOLO,
  pull : NRF_GPIO_PIN_NOPULL,
  is_watcher : false,
  hi_accuracy : true,
};

void ButtonsInit() {
  APP_ERROR_CHECK(nrf_drv_gpiote_init());
  APP_ERROR_CHECK(
      nrf_drv_gpiote_in_init(kButton0, &kGpioteConfig, &Button0Interrupt));
  APP_ERROR_CHECK(
      nrf_drv_gpiote_in_init(kButton1, &kGpioteConfig, &Button1Interrupt));
  APP_ERROR_CHECK(
      nrf_drv_gpiote_in_init(kButton2, &kGpioteConfig, &Button2Interrupt));
  APP_ERROR_CHECK(
      nrf_drv_gpiote_in_init(kButton3, &kGpioteConfig, &Button3Interrupt));
  APP_ERROR_CHECK(nrf_drv_gpiote_in_init(kResetButton, &kGpioteConfig,
                                         &ResetButtonInterrupt));
  nrf_drv_gpiote_in_event_enable(kButton0, true);
  nrf_drv_gpiote_in_event_enable(kButton1, true);
  nrf_drv_gpiote_in_event_enable(kButton2, true);
  nrf_drv_gpiote_in_event_enable(kButton3, true);
  nrf_drv_gpiote_in_event_enable(kResetButton, true);
  nrf_gpio_cfg_output(kStatusLed);
}

The ButtonNInterrupt functions basically put a function onto the scheduler that logs a log statement. I also put a log statement at the beginning of GPIOTE_IRQHandler in nrf_drv_gpiote.c, and it only triggers when I press Buttons 0-2, so the interrupt itself is not being called.

The interrupts all trigger on HITOLO. I probed the buttons, and they were held high when not pressed (~3.3V), and correctly went low when pressed (~0V). The whole board is powered from a 3.3V supply, so this seems correct. But, when I repeatedly read kResetButton's state using nrf_gpio_pin_read, it always returns 0.

I also read the PIN_CNF to see if anything changed, but they all look the same...

  // Read PIN_CNF
  sstl::vector<uint32_t, 10> buttons = {kButton0, kButton1, kButton2, kButton3, kResetButton};
  for (const auto& b : buttons) {
    LOG_I("PIN_CNF[%d]=%d", b, NRF_GPIO->PIN_CNF[b]);
  }
  
// Output is...
00> <info> app: PIN_CNF[15]=0
00> <info> app: PIN_CNF[12]=0
00> <info> app: PIN_CNF[7]=0
00> <info> app: PIN_CNF[9]=0
00> <info> app: PIN_CNF[10]=0

I also tried removing init of buttons 0-2, to see if some buffer was overflowing after 3 buttons, but Button3 and ResetButton still don't trigger.

What could be causing these two buttons to not trigger?

Edit Jan 1 2020:

I am using SDK 14.2, and using C++17 with the Arm GCC toolchain.

Einar Thorsrud · Accepted Answer

Hi, 
 I suspect the problem here is that you have not configured the pins as GPIO's in the UICR? As you can see from the pin assignments table , P0.09 and P0.10 can be either NFC or GPIO pins, and they are NFC pins by default. The easiest way to do this is to add CONFIG_NFCT_PINS_AS_GPIOS to your preprocessor defines.

GPIOTE not triggering for 2 of 5 buttons

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