nRF52840 DK P1.11 & P1.12 can not be used.

Question

Hello all,

I use nRF52840 for my custom board. I set P1.11 & P1.12 as UART_RX & UART_TX. But these two pins can not work.

Here is my nrf52840dk_nrf52840.overlay.

&pinctrl {
	uart0_default: uart0_default {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 12)>;
		};
		group2 {
			psels = <NRF_PSEL(UART_RX, 1, 11)>;
		};
	};

	uart0_sleep: uart0_sleep {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 12)>;
		};
		group2 {
			psels = <NRF_PSEL(UART_RX, 1, 11)>;
		};
	};
};

Here is my main.c.

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#include <stdio.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>

/* 1000 msec = 1 sec */
#define SLEEP_TIME_MS   1000

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)
#define LED1_NODE DT_ALIAS(led1)

/*
 * A build error on this line means your board is unsupported.
 * See the sample documentation for information on how to fix this.
 */
static const struct gpio_dt_spec led0 = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
static const struct gpio_dt_spec led1 = GPIO_DT_SPEC_GET(LED1_NODE, gpios);

void main(void)
{
	int ret;

	if (!device_is_ready(led0.port)) {
		return;
	}

	if (!device_is_ready(led1.port)) {
		return;
	}

	ret = gpio_pin_configure_dt(&led0, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
		return;
	}
	ret = gpio_pin_configure_dt(&led1, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
		return;
	}

	while (1) {
		ret = gpio_pin_toggle_dt(&led0);
		printf("blinky\n");
		ret = gpio_pin_toggle_dt(&led1);
		if (ret < 0) {
			return;
		}
		k_msleep(SLEEP_TIME_MS);
	}
}

My project build configuration is nrf52840dk_nrf52840.

Are these two pins used for other peripherals?

Thanks!