2009-11-9 AVR echo

This code tested on ATmega16

#include <avr/io.h>

#define FOSC 16000000UL
#define BAUD 9600
#define MYUBRR FOSC/16/BAUD-1

void USART_Init( unsigned int ubrr)
{
	UBRRH = (unsigned char)(ubrr>>8);
	UBRRL = (unsigned char)ubrr;
	UCSRB = (1<<RXEN)|(1<<TXEN);
	UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
}

int main()
{
	char c;
	USART_Init( MYUBRR );
	while(1)
	{
		while ( !(UCSRA & (1<<RXC))){};
		c = UDR;
		while (!(UCSRA & (1<<UDRE))){};
		UDR = c;
	}
	return 0;
}