samples/drivers/adc/boards/atsamd21_xpro.overlay

/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * Copyright (c) 2021 Argentum Systems Ltd.
 */

/ {
	zephyr,user {
		/* EXT-1, pin 3 ADC(+) */
		io-channels = <&adc 8>;
	};
};