qmk_firmware/keyboards/4by3/config.h

#pragma once

#include "config_common.h"

/* key matrix size */
#define MATRIX_ROWS 3
#define MATRIX_COLS 4

/* key matrix pins */
#define MATRIX_ROW_PINS { D1, D0, D4 }
#define MATRIX_COL_PINS { C6, D7, E6, B4 }
#define UNUSED_PINS

/* COL2ROW or ROW2COL */
#define DIODE_DIRECTION COL2ROW

/* Set 0 if debouncing isn't needed */
#define DEBOUNCE 5