[ARDUINO] USART zapalanie LED

#include <avr/io.h>

#define BAUDRATE 9600UL
#define PRESCALE (((F_CPU / (BAUDRATE * 16UL))) - 1)

#define LED_PIN (1<<5)
#define LED_PORT PORTB
#define LED_DDR DDRB

int main (void)
{
    uint8_t cmd;
    LED_DDR |= LED_PIN;
    UCSR0B |= (1<<RXEN0)|(1<<TXEN0);
    UBRR0 = PRESCALE;
    for(;;) {
        while ( !(UCSR0A & (1<<RXC0)) );
        cmd = UDR0;
        if (cmd == '1') {
            LED_PORT |= LED_PIN;
        } else if (cmd == '0') {
            LED_PORT &= ~LED_PIN;
        } else {
            LED_PORT ^= LED_PIN;
        }
    }
    return 0;
}