timer0.c

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//mtA
//#include <inavr.h>
//#include "iom169.h"
#include <avr/io.h>
#include <inttypes.h>
//#include <avr/signal.h>//This header file is obsolete.  Use <avr/interrupt.h>.
#include <avr/interrupt.h>
//mtE
#include "main.h"
#include "types.h"
#include "timer0.h"

TIMER_CALLBACK_FUNC CallbackFunc[TIMER0_NUM_CALLBACKS];

// Value definition:
// 0      The timer has expired
// 1-254  The timer is counting down
// 255    Free timer

// mt char CountDownTimers[TIMER0_NUM_COUNTDOWNTIMERS];
uint8_t CountDownTimers[TIMER0_NUM_COUNTDOWNTIMERS];

/*****************************************************************************
*
*   Function name : Timer0_Init
*
*   Purpose :       Initialize Timer/Counter 0
*
*****************************************************************************/
void Timer0_Init(void)
{
    //mt char i;
        uint8_t i;

    // Initialize array of callback functions
    for (i=0; i<TIMER0_NUM_CALLBACKS; i++)
        CallbackFunc[i] = NULL;

    // Initialize countdown timers
    for (i=0; i<TIMER0_NUM_COUNTDOWNTIMERS; i++)
        CountDownTimers[i] = 255;


        // Initialize Timer0.
        // Used to give the correct time-delays in the song

    // Enable timer0 compare interrupt
        TIMSK0 = (1<<OCIE0A);

    // Sets the compare value
        OCR0A = 31;

        // Set Clear on Timer Compare (CTC) mode, CLK/256 prescaler
        TCCR0A = (1<<WGM01)|(0<<WGM00)|(4<<CS00);
    // (8000000/256) / 31  =1008.06451612903Hz or 0.992ms 
    
        // Set Clear on Timer Compare (CTC) mode, CLK/1024 prescaler
        // TCCR0A = (1<<WGM01)|(0<<WGM00)|(5<<CS00);
        // (8000000/1024) / 31  = 252.01612903226Hz or 3.968ms 
    
}



/*****************************************************************************
*
*   Function name : TIMER0_COMP_interrupt
*
*   Purpose :       Check if any functions are to be called
*
*****************************************************************************/
// mtA
// #pragma vector = TIMER0_COMP_vect
// __interrupt void TIMER0_COMP_interrupt(void)
SIGNAL(SIG_OUTPUT_COMPARE0)
// mtE
{
    // mt char i;
        uint8_t i;
    
    for (i=0; i<TIMER0_NUM_CALLBACKS; i++)
        if (CallbackFunc[i] != NULL)
            CallbackFunc[i]();
    
    // Count down timers
    for (i=0; i<TIMER0_NUM_COUNTDOWNTIMERS; i++)
        if (CountDownTimers[i] != 255 && CountDownTimers[i] != 0)
            CountDownTimers[i]--;

}


/*****************************************************************************
*
*   Function name : Timer0_RegisterCallbackFunction
*
*   @param          pFunc pointer to function to add
*
*   Purpose :       Set up functions to be called from the 
*                   TIMER0_COMP_interrupt
*
*****************************************************************************/
BOOL Timer0_RegisterCallbackFunction(TIMER_CALLBACK_FUNC pFunc)
{
    // mt char i;
        uint8_t i;
    
    for (i=0; i<TIMER0_NUM_CALLBACKS; i++)
    {
        if (CallbackFunc[i] == pFunc)
            return TRUE;
    }
    
    for (i=0; i<TIMER0_NUM_CALLBACKS; i++)
    {
        if (CallbackFunc[i] == NULL)
        {
            CallbackFunc[i] = pFunc;
            return TRUE;
        }   
    }
    
    return FALSE;
}


/*****************************************************************************
*
*   Function name : Timer0_RemoveCallbackFunction
*
*   @param           pFunc pointer to function to remove
*
*   Purpose :       Remove functions from the list which is called int the
*                   TIMER0_COMP_interrupt
*
*****************************************************************************/
BOOL Timer0_RemoveCallbackFunction(TIMER_CALLBACK_FUNC pFunc)
{
    // mt char i;
        uint8_t i;
    
    for (i=0; i<TIMER0_NUM_CALLBACKS; i++)
    {
        if (CallbackFunc[i] == pFunc)
        {
            CallbackFunc[i] = NULL;
            return TRUE;
        }
    }
        
    return FALSE;
}
/*

char Timer0_AllocateCountdownTimer()
{
    // mt char i;
        uint8_t i;
        
    for (i=0; i<TIMER0_NUM_COUNTDOWNTIMERS; i++)
        if (CountDownTimers[i] == 255)
        {
            CountDownTimers[i] = 0;
            return i+1;
        }

    return 0;
}

void Timer0_SetCountdownTimer(char timer, char value)
{
    cli(); // mt __disable_interrupt();
    CountDownTimers[timer-1] = value;
    sei(); // mt __enable_interrupt();
}

char Timer0_GetCountdownTimer(char timer)
{
    char t;
    cli(); // mt __disable_interrupt();
    t = CountDownTimers[timer-1];
    sei(); // mt __enable_interrupt();
    
    return t;
}

void Timer0_ReleaseCountdownTimer(char timer)
{
    cli(); // mt __disable_interrupt();
    CountDownTimers[timer-1] = 255;
    sei(); // mt __enable_interrupt();
}
*/