Tooltron

/********

 * This file is part of Tooltron.

 *

 * Tooltron is free software: you can redistribute it and/or modify

 * it under the terms of the Lesser GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * Tooltron 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

 * Lesser GNU General Public License for more details.

 * You should have received a copy of the Lesser GNU General Public License

 * along with Tooltron.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright 2009 Kevin Woo <kwoo@2ndt.com>

 *

 ********/

/*

	serial.c - Functions for using the RS232 serial port

	author: Robotics Club, Colony Project

	much code taken from FWR's library, author: Tom Lauwers

	general note - serial -> uart

				   serial1 -> uart1

		this is done for clarity purposes

*/

#include <avr/io.h>

#include <stdio.h>

#include "serial.h"

//setup uart0 (serial)

void serial_init(unsigned int ubrr)

{

    DDRD |= (1<<PD1);

    DDRD &= ~(1<<PD0);

    UDR0 = 0;

	/*Set baud rate - baud rates under 4800bps unsupported */

	UBRR0H = 0x00;

	UBRR0L = (unsigned char)ubrr;

    //UCSR0A |= (1<<U2X0);

	/*Enable receiver and transmitter */

	UCSR0B |= (1<<RXEN0)|(1<<TXEN0);

	/* Set frame format: 8data, 1stop bit, asynchronous normal mode */

	UCSR0C |= (1<<UCSZ00) | (1<<UCSZ01);

}

// uart_putchar - Low-level function which puts a value into the 

// Tx buffer for transmission.  Automatically injects

// a \r before all \n's

int serial_putchar(char c)

{

    if (c == '\n')

		putchar('\r');

	// Wait until buffer is clear for sending

    loop_until_bit_is_set(UCSR0A, UDRE0);

    //while ( !(UCSR0A & (1<<UDRE0)));

	// Load buffer with your character

    UDR0 = c;

    return 0;

}

// uart_getchar - Low-level function which waits for the Rx buffer

// to be filled, and then reads one character out of it.

// Note that this function blocks on read - it will wait until

// something fills the Rx buffer.

int serial_getchar(void)

{

	char c;

	// Wait for the receive buffer to be filled

    loop_until_bit_is_set(UCSR0A, RXC0);

	// Read the receive buffer

    c = UDR0;

	return c;

}

// uart_getchar_nb - Low-level function which checks if the Rx buffer

// is filled, and then reads one character out of it.

// This is a non blocking version uart_getchar

int serial_getchar_nb(void)

{

	char c;

	// Wait for the receive buffer to be filled

    //loop_until_bit_is_set(UCSR0A, RXC0);

	if (UCSR0A & _BV(RXC0)){

		// Read the receive buffer

		c = UDR0;

		return c;

	}

	return 0;

}