Taiyo Yuden EYSHJNZXZ (nRF52832) cannot use NFC pins as GPIO

[NewAce]

I am having trouble using GPIO P0_9 and P0_10 as GPIO pins. These are the pins designated as NFC1 and NFC2.

I am using the following sample code:

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

/**
 * @brief Function for application main entry.
 */
int main(void)
{
    nrf_gpio_cfg_output(9);
    nrf_gpio_cfg_output(10);

    while (true)
    {
    nrf_gpio_pin_toggle(9);
    nrf_gpio_pin_toggle(10);
    nrf_delay_ms(500);
    }
}

I have confirmed that UICR 0x20C is set to 0xFFFFFFFE:

sh-3.2# nrfjprog --memrd 0x1000120c --family nrf52
0x1000120C: FFFFFFFE                              |....|

I can use any other pin for GPIO, except P0_9 and P0_10. Any insights as to what is going on, would be greatly appreciated.

[NewAce]

I discovered that the issue was actually a module alignment issue on the PCB. After throwing the board back into the reflow oven, the outputs started working. My bad. For anyone stumbling onto this question and using the NRF52832 / NRF52_DK with MBED-CLI, the targets.json file needs to be modified in order to include the CONFIG_NFCT_PINS_AS_GPIOS define, as Daniel hinted to above:

"NRF52_DK": {
        "supported_form_factors": ["ARDUINO"],
        "inherits": ["MCU_NRF52"],
        "macros_add": ["BOARD_PCA10040", "NRF52_PAN_12", "NRF52_PAN_15", "NRF52_PAN_58", "NRF52_PAN_55", "NRF52_PAN_54", "NRF52_PAN_31", "NRF52_PAN_30", "NRF52_PAN_51", "NRF52_PAN_36", "NRF52_PAN_53", "S132", "CONFIG_NFCT_PINS_AS_GPIOS", "BLE_STACK_SUPPORT_REQD", "SWI_DISABLE0", "NRF52_PAN_20", "NRF52_PAN_64", "NRF52_PAN_62", "NRF52_PAN_63"],
        "device_has": ["ANALOGIN", "ERROR_PATTERN", "I2C", "I2C_ASYNCH", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPI_ASYNCH", "SPISLAVE"],
        "release_versions": ["2", "5"],
        "device_name": "nRF52832_xxAA"
    },