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timer.c

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// This file has been prepared for Doxygen automatic documentation generation.
#include "timer.h"
#include "common.h"
#include "config.h"



#define TIMER_PRESCALER_VALUE ((1<<CS12) | (0<<CS11) | (1<<CS10))
#define SHORT_TIMEOUT_VALUE 100



volatile bool shortTimeout;
volatile bool longTimeout;

static byte longTimeoutHighCounter;



#pragma vector = TIMER1_COMPA_vect
__interrupt void shortTimeoutHandler(void)
{
        // Set timeout flag.
        shortTimeout = true;
        // Disable this interrupt.
        TIMSK1 &= ~(1<<OCIE1A);
}



#pragma vector = TIMER1_COMPB_vect
__interrupt void longTimeoutHandler(void)
{
        // Count down.
        if( longTimeoutHighCounter > 0 ) {
                if( --longTimeoutHighCounter == 0 ) {
                        OCR1B = TCNT1 + LONG_TIMEOUT_LO_VALUE;
                }
        } else {
                // Set timeout flag.
                longTimeout = true;
                // Disable this interrupt.
                TIMSK1 &= ~(1<<OCIE1B);
        }
}



void startShortTimeout(void)
{
        // Clear timeout flag.
        shortTimeout = false;
        // Initialize compare value relative
        // to current timer value.
        OCR1A = TCNT1 + SHORT_TIMEOUT_VALUE;
        // Clear pending interrupt flag.
        TIFR1 |= (1<<OCF1A);
        // Enable interrupt.
        TIMSK1 |= (1<<OCIE1A);
        // Start timer/counter if not started yet.
        TCCR1B = TIMER_PRESCALER_VALUE;
}



void startLongTimeout(void)
{
        // Clear timeout flag.
        longTimeout = false;
        // Initialize countdown value.
        longTimeoutHighCounter = LONG_TIMEOUT_HI_VALUE;
        // Initialize compare value to one less than
        // current counter value, so that we do not get
        // an interrupt immediately.
        OCR1B = TCNT1 - 1;
        // Clear pending interrupt flag.
        TIFR1 |= (1<<OCF1B);
        // Enable interrupt.
        TIMSK1 |= (1<<OCIE1B);
        // Start timer/counter if not started yet.
        TCCR1B = TIMER_PRESCALER_VALUE;
}



void stopTimer(void)
{
        TCCR1B = 0x00;
        shortTimeout = false;
        longTimeout = false;
}