Using GPIO Pins with shared functionality

[JasonPierpont]

I am developing on an nRF52811 and I've noticed that I can't set/clear the pins such as the ones in the bracket in the picture below. 

I'm using nrf_gpio_cfg_output(pin_num) to see the pin as an output and then using nrf_gpio_cfg_set/nrf_gpio_cfg_clear to change the value of the pin, but I'm not seeing any changes. 

I've also tried this: nrf_gpio_cfg(0, NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE); for configuration. I've also tried other pulls and drives just to make sure I'm not using the incorrect one. 

I am able to successfully change the value of the other pins (such as P0.06) with no problem. I'm not sure if I am missing a configuration step or if they're not able to be used in the way I want at all.

[Jørgen Holmefjord]

Hi,

You should be able to use these pins without any additional configuration, as long as the pins are not assigned to any other peripherals (CLOCK, SAADC, GPIOTE, UART/SPI/TWI, etc). XL1/XL2 will be used by the LFCLK if you have started this with LFXO configuration.

Have you tried a minimal example, with no other code than configuring/toggling the GPIOs, like the blinky peripheral example?

Are you using nRF5 SDK, or nRF Connect SDK?

Best regards,
Jørgen

[Jørgen Holmefjord]

Have you tried with the Blinky example, with the BSP function calls removed/commented out?

If you are not seeing toggles with such a minimal example, there is probably some HW issue on the board, or problems with the way you check the toggling. If you can share the full program code of your test-application, I can try it out on one of our nRF52811 boards.

[JasonPierpont]

Yes, I have tried with the BSP stuff removed. 

Here is my code:  

#define PIN 0

#include <stdbool.h>
#include <stdint.h>
#include "nrf_delay.h"
#include "boards.h"

int main(void)
{
    nrf_gpio_cfg_output(PIN);

    while (true)
    {
        nrf_gpio_pin_set(PIN);
        nrf_delay_ms(2000);
        nrf_gpio_pin_clear(PIN);
        nrf_delay_ms(2000);
    }
}

[Jørgen Holmefjord]

Hi,

I verified that your code does toggle the GPIOs on P0.00-P0-05 correctly on my nRF52811 board.

Do you see this issue on a single board, or on multiple nRF52811 boards?

Best regards,
Jørgen

[JasonPierpont]

Hi, 

It was occurring on multiple boards. I was troubleshooting a very small Flex PCB and there may have been some poor connections. Everything is working now. Thanks for the assistance.

[JasonPierpont]

The issue was that P0.00 and P0.01 are reserved for XTAL.