serial.c

/*
  wiring_serial.c - serial functions.
  Part of Arduino - http://www.arduino.cc/

  Copyright (c) 2005-2006 David A. Mellis

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA

  $Id: serial.c,v 1.1 2009/09/19 05:36:16 mars Exp $
*/

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

typedef void (*voidFuncPtr)(void);

#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

void beginSerial(long baud)
{
#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__)
	UBRR0H = ((F_CPU / 16 + baud / 2) / baud - 1) >> 8;
	UBRR0L = ((F_CPU / 16 + baud / 2) / baud - 1);
	
	// enable rx and tx
	sbi(UCSR0B, RXEN0);
	sbi(UCSR0B, TXEN0);
	
	// enable interrupt on complete reception of a byte
	sbi(UCSR0B, RXCIE0);
#else
	UBRRH = ((F_CPU / 16 + baud / 2) / baud - 1) >> 8;
	UBRRL = ((F_CPU / 16 + baud / 2) / baud - 1);
	
	// enable rx and tx
	sbi(UCSRB, RXEN);
	sbi(UCSRB, TXEN);
	
	// enable interrupt on complete reception of a byte
	sbi(UCSRB, RXCIE);
#endif
	
	// defaults to 8-bit, no parity, 1 stop bit
}

void serialWrite(unsigned char c)
{
#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__)
	while (!(UCSR0A & (1 << UDRE0)))
		;

	UDR0 = c;
#else
	while (!(UCSRA & (1 << UDRE)))
		;

	UDR = c;
#endif
}