//#define TEST
/****************************************************************************
 Module
     steps12.c

 Description
     This is a module to drive a 2-phase stepper motor using the 
     CMPE118 LM298 dual H-Bridge Module.  The module uses a 
     periodic interrupt to act as a heartbeat.  The stepper is then advanced
     at a multiple of that frequency.
 Notes
    This module requires the termio.c file also.  STEPS12_Init currently
    uses the TERMIO_Init function to properly initialize the PLL clk. (24Mhz)    
     
 History
 When           Who     What/Why
 -------------- ---     --------
 02/01/06 13:34 rjk      Began Coding
****************************************************************************/

/*----------------------------- Include Files -----------------------------*/
#include <hidef.h>         /* common defines and macros */
#include <mc9s12c32.h>     /* derivative information */
#include <steps12.h>
#include <stdio.h>
#include <termio.h>

/******* GLOBALS  ****************************/
#define PERIOD 188
#define MAX_STEPS 4 // total number of step states for driving FULL STEP
static unsigned char StepDirection;
static long StepsLeft;
static int StepState;
static long StepPeriod;
static long Counter;
static unsigned char CurrentlyStepping=0;


/****************************************************************************
 Function
     STEPS12_Init

 Parameters
     Period: Number of milliseconds between each step (must be an integer);
     Direction: 0 for CW or non-zero for CCW
     Steps: Number of steps to advance motor

 Returns
     None.

 Description
     Initializes the RTI module for OSCCLK=8MHz and sets global variables. 
 Notes
     
 ****************************************************************************/
void STEPS12_Init(long Period, unsigned char Direction, long Steps) {    
    
    TERMIO_Init();

   TIOS |= TIOS_IOS4_MASK; // enable output capture
   TSCR1 |= TSCR1_TEN_MASK; // enable timer module
   TCTL1 &= ~(TCTL1_OM4_MASK|TCTL1_OL4_MASK); // disconnects output pins from TIM
  TSCR2 |= (TSCR2_PR0_MASK|TSCR2_PR1_MASK|TSCR2_PR2_MASK);
  TSCR2 &= ~(TSCR2_TCRE_MASK|TSCR2_TOI_MASK);
      
   TC4 = TCNT+PERIOD;
   TFLG1=TFLG1_C4F_MASK;
   TIE |= TIE_C4I_MASK;   
    
    StepDirection=Direction;
    StepsLeft=Steps;
    StepState=1;
    StepPeriod=Period;
    Counter=1;
    CurrentlyStepping=1;
    
    DDRA|=0x0F; // First 4 pins on PORTA all set to be outputs.
  
    EnableInterrupts;
 
  return; 
}


/****************************************************************************
 Function
     STEPS12_RTI_Resp     

 Parameters
     None.

 Returns
     None.

 Description
     Interrupt routine that consists of the state machine for stepping the motor 
     in the proper order.  Interrupt Routine to handle RTI.  Function will be
     executed by rate defined in STEPS12_Init.
     
 Notes
 
****************************************************************************/


void interrupt 12 STEPS12_OC4_Resp(void)
{  
   TC4 += PERIOD;
   TFLG1=TFLG1_C4F_MASK;   

    
   if(Counter>=StepPeriod)
    Counter=1;
   else {
    Counter++;
    return;
   }
   
  
   if(StepsLeft<=0) {
    CurrentlyStepping=0;
    return;
   } else
    StepsLeft--;
      
   if(StepDirection)  {
    if(StepState>=MAX_STEPS)
      StepState=1;
    else
      StepState++;
   } else {
    if(StepState<=1)
      StepState=MAX_STEPS;
    else
      StepState--;
   }
   
   // Use PortA for motor direction logic
   // PortA0 = Motor 1 enable
   // PortA1 = Motor 1 direction
   // PortA2 = Motor 2 enable
   // PortA3 = Motor 2 direction
   
   // For Full Step driving both motor outputs always enabled
   // HINT: both motors outputs will not always be on for wave driving or
   //       half step driving!
   PORTA|=PORTA_BIT0_MASK;
   PORTA|=PORTA_BIT2_MASK;
   
   switch(StepState) {
    case 1:
      PORTA|=PORTA_BIT1_MASK;
      PORTA|=PORTA_BIT3_MASK;  
      break;
    case 2:
    	PORTA|=PORTA_BIT1_MASK;
      PORTA&=~PORTA_BIT3_MASK;
      break;
    case 3:
      PORTA&=~PORTA_BIT1_MASK;
      PORTA&=~PORTA_BIT3_MASK;
      break;     
    case 4:
      PORTA&=~PORTA_BIT1_MASK;
      PORTA|=PORTA_BIT3_MASK;
      break;
   }						  
   
   return;
}

/****************************************************************************
 Function
     STEPS12_Stop     

 Parameters
     None.

 Returns
     None.

 Description
     Stops the RTI from advancing the motor.
     
 Notes
 
****************************************************************************/


void STEPS12_Stop(void) {
   StepsLeft=0;
   CurrentlyStepping=0;
   
   return; 
}

/****************************************************************************
 Function
     STEPS12_IsStepping

 Parameters
     None.

 Returns
     1 is StepsLeft > 1, non-zero if finished stepping.

 Description
     Used to check status of stepper motor driver.
     
 Notes
 
****************************************************************************/

unsigned char STEPS12_IsStepping(void) {
  return CurrentlyStepping;
  
}


#ifdef TEST

void main(void) {  
 
  while(1) {
   while(STEPS12_IsStepping()); // wait until the active steps are done
   STEPS12_Init(10,1,100); 
   while(STEPS12_IsStepping());
   STEPS12_Init(10,0,100); 
  }
  
 return;
}


#endif // TEST
/*------------------------------ End of file ------------------------------*/