qmk-firmware/keyboards/melody96/melody96.c

#include "melody96.h"

void led_set_kb(uint8_t usb_led) {
	if (usb_led & (1 << USB_LED_NUM_LOCK)) {
		DDRC |= (1 << 6); PORTC &= ~(1 << 6);
	} else {
		DDRC &= ~(1 << 6); PORTC &= ~(1 << 6);
	}

	if (usb_led & (1 << USB_LED_CAPS_LOCK)) {
		DDRC |= (1 << 7); PORTC &= ~(1 << 7);
	} else {
		DDRC &= ~(1 << 7); PORTC &= ~(1 << 7);
	}

	if (usb_led & (1 << USB_LED_SCROLL_LOCK)) {
		DDRB |= (1 << 5); PORTB &= ~(1 << 5);
	} else {
		DDRB &= ~(1 << 5); PORTB &= ~(1 << 5);
	}

    led_set_user(usb_led);
}