CTimer3.h

#pragma once

#include "CBitio.h"
#include "CStepTimer.h"         // Base class

//----------------------------------------------------------------------------
//
//----------------------------------------------------------------------------

#ifdef TIMSK3   // Check for processor support

class CTimer3: public CStepTimer
{
private:
        // Define Prescale Values
        static const char STOPPED = 0;
        static const char DIV1 = 1;
        static const char DIV8 = 2;
        static const char DIV64 = 3;
        static const char DIV256 = 4;
        static const char DIV1024 = 5;
        static const char EXT_FALLING = 6;
        static const char EXT_RISING = 7;
        
        static const char prescaleMask = ~(_BV(CS12) | _BV(CS11) | _BV(CS10));
        char prescale;                                          // Save prescale here for on/off
        
public:
        // Legacy I/O
        // CBit(B, 1, WO) stepBit;                      // Define the ouput compare bit
        
        // StepperII I/O DEBUG ONLY!!!  Don't run on fully populated board.
        //CBit(B, 5, WO) oc1a;                          // Show OC1A activity
        //CBit(B, 6, WO) oc1b;                          // Show OC1B activity

        void init(void);                                        // Initialize for stepper app
        inline void on(void);
        inline void off(void);
        inline void outputEnable(void);
        inline void outputDisable(void);
        void load(int period);                          // Load timer interval register
};

//-----------------------------------------------------------------------------
// on()
//      Start the timer
//-----------------------------------------------------------------------------
inline void CTimer3::on(void)
{
        // The order of events is important here
        // Must call outputEnable() before enabling timer to get proper output
        
        //TCNT3 = 1;                                                    // Reset counter
        TCNT3 = OCR3B + 5;                                              // Set past OCB
        outputEnable();                                                                 // Clear and enable int
        TCCR3B = (TCCR3B & prescaleMask) | prescale;    // Load prescale
}

//-----------------------------------------------------------------------------
// off()
//      Stop the timer
//-----------------------------------------------------------------------------
inline void CTimer3::off(void)
{
        TCCR3B = (TCCR3B & prescaleMask) | STOPPED;             // Stop the clock
        outputDisable();
}

//-----------------------------------------------------------------------------
// outputEnable()
//      Enable the output compare B interrupt which generate stepper pulses
//-----------------------------------------------------------------------------
inline void CTimer3::outputEnable(void)
{
        TIFR3  |= _BV(OCF3B);                           // Clear the interrupt request
        TIMSK3 |= _BV(OCIE3B);                          // Enable output compare B interrupt
}

//-----------------------------------------------------------------------------
// outputDisable()
//      Disable the output compare B interrupt resulting in no stepper pulses
//-----------------------------------------------------------------------------
inline void CTimer3::outputDisable(void)
{
        TIMSK3 &= ~_BV(OCIE3B);                         // Disable output compare B interrupt
}

#else 
#error Processor Not Supported!
#endif