AVR UART

main.c

#include <avr/io.h>
#include <util/delay.h>

/* 9600 8n1 com */

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

int main(void) 
{   
     /*Set baud rate */
    UBRR0H = (unsigned char)(BAUDRATE>>8);
    UBRR0L = (unsigned char)BAUDRATE;
    /* Enable receiver and transmitter */
    UCSR0B = (1<<RXEN0)|(1<<TXEN0);
    /* Set frame format: 8data, 1stop bit */
    UCSR0C = (1<<USBS0)|(3<<UCSZ00);

    for(;;) {
        /* Wait for empty transmit buffer */
        while ( !( UCSR0A & (1<<UDRE0)) )
        ;
        /* Put data into buffer, sends the data */
        UDR0 =  'u';

        /* wait half a sec before sending again*/
        _delay_ms(500);
    }
    return 0;
}