qmk_firmware/keyboards/handwired/gamenum/keymaps/default/keymap.c

#include QMK_KEYBOARD_H


#define DEF 0
#define HDN 1
#define OSY 2

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  [DEF] = LAYOUT(
    TO(HDN), KC_SLSH, KC_ASTR, KC_MINS, \
    KC_7,    KC_8,    KC_9,    KC_PLUS, \
    KC_4,    KC_5,    KC_6,             \
    KC_1,    KC_2,    KC_3,             \
    KC_0,             KC_DOT,  KC_ENT   \
  ),
  [HDN] = LAYOUT(
    TO(OSY), KC_1,    KC_2,    KC_3,    \
    KC_Q,    KC_W,    KC_E,    KC_R,    \
    KC_A,    KC_S,    KC_D,             \
    KC_Z,    KC_X,    KC_C,             \
    KC_LSFT,          KC_LALT, KC_SPC   \
  ),
  [OSY] = LAYOUT(
    KC_A,    KC_Q,    KC_1,    TO(DEF), \
    KC_S,    KC_W,    KC_2,    KC_LALT, \
    KC_D,    KC_E,    KC_3,             \
    KC_F,    KC_R,    KC_4,             \
    KC_SPC,           KC_T,    KC_TAB   \
  )
};

bool process_record_user(uint16_t keycode, keyrecord_t *record) {
  switch(keycode) {
    case TO(HDN):
      if (record->event.pressed) {
        PORTC |= (1 << 6); // PC6 goes high
      }

      return true;

    case TO(OSY):
      if (record->event.pressed) {
        PORTC &= ~(1 << 6); // PC6 goes high
        PORTD |= (1<<4);
      }

      return true;

    case TO(DEF):
      if (record->event.pressed) {
        PORTD &= ~(1 << 4); // PC6 goes high
      }

      return true;

    default:
      return true;
  }
}