uart.c
#include <avr/io.h>
#include <stdio.h>

#ifndef BAUD
#define BAUD 9600
#endif
#include <util/setbaud.h>
#include "uart.h"

FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
//FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);

void uart_init(void) {
    UBRR0H = UBRRH_VALUE;
    UBRR0L = UBRRL_VALUE;

    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); /* 8-bit data */ 
    //UCSR0B = _BV(RXEN0) | _BV(TXEN0);   /* Enable RX and TX */    
    UCSR0B = _BV(TXEN0);   /* Enable TX */    

    stdout = &uart_output;
    //stdin  = &uart_input;
}

int uart_putchar(char c, FILE *stream) {
    loop_until_bit_is_set(UCSR0A, UDRE0);
    UDR0 = c;
    return (0);
}

/*
int uart_getchar(FILE *stream) {
    loop_until_bit_is_set(UCSR0A, RXC0);
    return (UDR0);
}
*/