#define F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>

void setup() {
    // Set PB0 (Digital Pin 8) as output
    DDRB |= (1 << PB0);
}

void loop() {
    // Toggle PB0
    PORTB ^= (1 << PB0);
    _delay_ms(500);
}