qmk_firmware/keyboards/preonic/preonic.c

#include QMK_KEYBOARD_H

#ifdef ONEHAND_ENABLE
__attribute__ ((weak))
const keypos_t hand_swap_config[MATRIX_ROWS][MATRIX_COLS] = {
  {{11, 0}, {10, 0}, {9, 0}, {8, 0}, {7, 0}, {6, 0}, {5, 0}, {4, 0}, {3, 0}, {2, 0}, {1, 0}, {0, 0}},
  {{11, 1}, {10, 1}, {9, 1}, {8, 1}, {7, 1}, {6, 1}, {5, 1}, {4, 1}, {3, 1}, {2, 1}, {1, 1}, {0, 1}},
  {{11, 2}, {10, 2}, {9, 2}, {8, 2}, {7, 2}, {6, 2}, {5, 2}, {4, 2}, {3, 2}, {2, 2}, {1, 2}, {0, 2}},
  {{11, 3}, {10, 3}, {9, 3}, {8, 3}, {7, 3}, {6, 3}, {5, 3}, {4, 3}, {3, 3}, {2, 3}, {1, 3}, {0, 3}},
  {{11, 4}, {10, 4}, {9, 4}, {8, 4}, {7, 4}, {6, 4}, {5, 4}, {4, 4}, {3, 4}, {2, 4}, {1, 4}, {0, 4}},
};
#endif

void matrix_init_kb(void) {

    // Turn status LED on
    DDRE |= (1<<6);
    PORTE |= (1<<6);

	matrix_init_user();
};