#include <avr/io.h>
#include <stdlib.h>
#include "usart.h"
#include "conf.h"
#include "ringbuffer.h"

volatile ringbuffer_t usart_buffer;


void
usart_init(void)
{
	usart_buffer = ringbuffer_new(USART_BUFFER_SIZE);
	UBRRH = (unsigned char)(UBRR_VALUE >> 8);
	UBRRL = (unsigned char)UBRR_VALUE;
	UCSRB = _BV(TXEN) | _BV(TXCIE);
	UCSRC = _BV(USBS) | _BV(UCSZ0) | _BV(UCSZ1);
}

int
usart_putc(char c)
{
	return ringbuffer_put_char(usart_buffer, c);
}
	


ISR(USART_TX_vect)
{
	if(ringbuffer_nonempty(usart_buffer))
	{
		while(!(UCSRA & UDRE));
		UDR = ringbuffer_get_char(usart_buffer);
	}
}