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>

 *

 ********/

/** @file timer.c

 * 

 *  @brief Implements the timer functions. See timer.h for full details

 *

 *         @author Kevin Woo (kwoo)

 */

#include "timer.h"

#include <avr/io.h>

#include <avr/interrupt.h>

char timeout_flag=0;

char get_timeout_flag(void){

  return timeout_flag;

}

//Initializes all the timer1 registers

void init_timer() {

        //Clears the control registers for timer 1

        TCCR1A = 0x00;

        TCCR1B = 0x00;

        TCCR1C = 0x00;

        TIMSK1 = 0x00;

        /*****

         * Output control register A set to clear timer on compare match.

         * Output control register B not connected.

         * WGM is in normal operation.

         * Clock is divided by 256. (This sets it to disconnected, connects

         *   in start_timer to above value).

         *****/

        TCCR1A |= _BV(COM1A1);

        //Compares at 1 second with an 8MHz Clock and a 256 prescale. (31250)

        OCR1AH = 0x7A;

        OCR1AL = 0x12;

        //Enable the output compare register 1A interrupt

        TIMSK1 |= _BV(OCIE1A);

        timeout_flag = 0;

        return;

}

void start_timer() {

        //Enables the timer. Sets prescale to 256.

        TCCR1B |= _BV(CS12);

        return;

}

void stop_timer() {

        //Disables timer.

        TCCR1B &= ~_BV(CS12);

        seconds = 0;

        minutes = 0;

        return;

}

void reset_timer() {

        seconds = 0;

        minutes = 0;

        return;

}

void set_timeout_flag() {

    timeout_flag = 1;

    return;

}

void reset_timeout_flag() {

    timeout_flag = 0;

    return;

}

ISR(TIMER1_COMPA_vect) {

        if (seconds == 59) {

                minutes++;

                seconds = 0;

        } else {

                seconds++;

        }

}