Need some clarification on function nrf_gpio_cfg_output

[AllenS]

I am not sure what I am missing in this.  This is a custom board so there is no other circuitry on this pin other than a pad to monitor the signal changes with.

#define DBG_PIN_NUMBER                  9   // P0.09 -> Debug output pin

//-----------------------------------------------------------------------------
static void app_vars_init(void)
{
 nrf_gpio_cfg_output(DBG_PIN_NUMBER);
 
 nrf_gpio_pin_write(DBG_PIN_NUMBER, 1);
}

When my main function calls the init code above, I go and look at the pin and only see a signal output at ground.

#define DBG_PIN_NUMBER                  9   // P0.09 -> Debug output pin

//-----------------------------------------------------------------------------
static void app_vars_init(void)
{
  nrf_gpio_cfg_input(DBG_PIN_NUMBER, NRF_GPIO_PIN_PULLUP);
}

If I change the pin to an input with a pullup resistor, I see the 3VDC on the o-scope.  So I am pretty sure there is nothing wrong with the pin or any of the traces.

Any idea why when I set this pin to be an output and set the pin high that I do not see 3VDC?

Thanks in advance.

[AllenS]

FYI.  I am using nRF5_SDK_17.1.0. The output config define does disconnect the input buffer.

[Einarh]

Hello

Have you tried putting a short delay between cfg_output and pin_write?

Best regards,

Einar

[mrono]

Pin 0.09 is one of the NFC pins. You need to explicitly enable the GPIO function on that pin. CONFIG_NFCT_PINS_AS_GPIOS  is the define you need.

[AllenS]

Where is this define located?  I checked sdk_config.h and nrf_gpio.h and was not able to find it.  Any suggestions?

[AllenS]

Actually I did by debugging step by step in the code.