USART test. Atmega8. Without interrupts.

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

#define XTAL 8000000L
#define BAUDRATE 9600L
#define BAUDDIVIDER (XTAL/(16*BAUDRATE)-1)

void init(void);
void sendString(char *str);
void sendByte(char byte);

char *string = "I am USART test message";

int main(void) {

    init();

    sei();

    sendString(string);

    return 0;

}

void init(void) {
    DDRB = 0xff;
    PORTB = 0xff;
    UBRRH = BAUDDIVIDER >> 8;
    UBRRL = BAUDDIVIDER & 0xFF;

    UCSRA = 0;
    UCSRB = (1 << RXEN) | (1 << TXEN) | (1 << RXCIE) | (1 << TXCIE) | (0 << UDRIE);
    UCSRC = (1 << URSEL) | (1 << UCSZ0) | (1 << UCSZ1);
}

void sendString(char *str) {
    while(*str != '\0') {
        sendByte(*str);
        str++;
    }
}

void sendByte(char byte) {
    while(!(UCSRA & (1 << UDRE)));
    UDR = byte;
}