GPIO/GPIOTE interrupts not triggered at every event

Question

Hi, 
 
 My goal is to generate a GPIO or GPIOTE interrupt and inside the ISR sample 8-bits from GPIO. 
 I tried modifying two sample projects to achieve this, the NRFX and the button projects, but I got similar results from both. I started by toggling a pin inside the ISR to check if the ISR is triggered for every event and I found that it is not happening for higher frequencies. 
 See some examples below of various input frequencies to the GPIOTE pin and toggling another pin in the GPIOTE_ISR. 
 
 2 MHz input signal

500 kHz input signal

100 kHz input signal

50 kHz input signal

10 kHz input signal

Is this an expected result? Can it be improved? 
 
 Thank you.

Einar Thorsrud · Accepted Answer

Ah, I did not notice this before, but the nrfx sample does not handle GPIO pins from port 1. When yo use a pin from port 1, the pin number should be 32 + the P1 pin. So for instance, P1.15 is pin 47. This is normally handled more elegantly when using the Zephyr GPIO API, but when using nrfx directly that is not the case. You can for instance to it like this, though: Specify the pin in an overlay file like you have before: &button0 { gpios = <&gpio1 15 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>; }; Then you can check the port and add 32 as needed as shown in this diff from the nrfx sample in nRF Connect SDK 1.9.1: Fullscreen 6180.main.c.diff Download diff --git a/samples/boards/nrf/nrfx/src/main.c b/samples/boards/nrf/nrfx/src/main.c index 5c2f2a6b55..64e60d6534 100644 --- a/samples/boards/nrf/nrfx/src/main.c +++ b/samples/boards/nrf/nrfx/src/main.c @@ -17,9 +17,10 @@ #include LOG_MODULE_REGISTER(nrfx_sample, LOG_LEVEL_INF); -#define INPUT_PIN DT_GPIO_PIN(DT_ALIAS(sw0), gpios) #define OUTPUT_PIN DT_GPIO_PIN(DT_ALIAS(led0), gpios) +uint32_t m_input_pin; + static void button_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action) { LOG_INF("GPIO input event callback"); @@ -27,7 +28,15 @@ static void button_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action) void main(void) { - LOG_INF("nrfx_gpiote sample on %s", CONFIG_BOARD); + if (strcmp(DT_GPIO_LABEL(DT_ALIAS(sw0), gpios), "GPIO_1") == 0) { + m_input_pin = 32 + DT_GPIO_PIN(DT_ALIAS(sw0), gpios); + } + else { + m_input_pin = DT_GPIO_PIN(DT_ALIAS(sw0), gpios); + } + + LOG_INF("nrfx_gpiote sample on %s. Input pin is: %u", CONFIG_BOARD, m_input_pin); + nrfx_err_t err; @@ -56,7 +65,7 @@ void main(void) /* Initialize input pin to generate event on high to low transition * (falling edge) and call button_handler() */ - err = nrfx_gpiote_in_init(INPUT_PIN, &in_config, button_handler); + err = nrfx_gpiote_in_init(m_input_pin, &in_config, button_handler); if (err != NRFX_SUCCESS) { LOG_ERR("nrfx_gpiote_in_init error: %08x", err); return; @@ -77,7 +86,7 @@ void main(void) return; } - nrfx_gpiote_in_event_enable(INPUT_PIN, true); + nrfx_gpiote_in_event_enable(m_input_pin, true); nrfx_gpiote_out_task_enable(OUTPUT_PIN); LOG_INF("nrfx_gpiote initialized"); @@ -100,7 +109,7 @@ void main(void) * the button is pressed, the LED pin will be toggled. */ nrfx_gppi_channel_endpoints_setup(channel, - nrfx_gpiote_in_event_addr_get(INPUT_PIN), + nrfx_gpiote_in_event_addr_get(m_input_pin), nrfx_gpiote_out_task_addr_get(OUTPUT_PIN)); /* Enable (D)PPI channel. */ (I have kept the output pin as is here, but you can change that as well).

GPIO/GPIOTE interrupts not triggered at every event

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