/*
 * stepper.c
 *    A program that turns turns the stepper motor, first clockwise, then
 *    counter-clockwise
 *
 * Author: C.Schramm
 * Date: February 10, 2006
 */

#define _IO_BASE        0
#define _ADDR(off)      (unsigned char volatile *)(_IO_BASE + off)
#define _P(off)         *(unsigned char volatile *)(_IO_BASE + off)
#define DDRP    _P(0x025A)
#define PTP     _P(0x0258)
#define PTT     _P(0x0240)
#define DDRT    _P(0x0242)

void delay(int n);

void main(void)
{
 	int i;
	
	// Initialize the ports required for the Stepper motor	
	// DO NOT ALTER
	DDRT |= 0b01100000;
	DDRP |= 0b00100000;
	PTP |= 0b00100000;
	PTT = 0b01100000;
	
	//Spin Stepper Motor in the clockwise direction
	for(i = 0; i < 5; i++)		// for: Repeats whatever follows between {...}
	{ 	  	   	   	  			// TIP: You may change the number of times it repeats,
	    						//      but to begin, let it as '5'. 
		// TO BE COMPLETED: In each statement below, a dummy value has been
		// 	  	 			sent to Port T. You must supply the correct
		//					sequence of values so that the two stators in our
		//					stepper motor are activated so as to induce clockwise
		//					motion in the rotor.
		//					Remember: Port T Bit 5 is the vertical stator 
		//							  Port T Bit 6 is the horizontal stator
		// TIP: You may alter the length of the delay, to make your motor
		//      change at quicker or slower intervals
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
	}
 	//Spin Stepper Motor in the counter-clockwise direction	
	for(i = 0; i < 5; i++)
	{ 
	    // TO BE COMPLETED: Repeat as above, but reverse the direction.
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
		PTT = 0b00000000; delay(5);
	}

} 

/* delay
 *   Does idle work for a period of time, keeping the CPU busy
 *   but doing nothing useful
 */
void delay(int n)
{
	int x;
	int y;
	int dummy = 1000;
	for (;n>0;n--)
	{
	 for(y=0; y<0x1F; y++)
	 {
	  for(x=0; x<0x1FF; x++)
	  {
		dummy = dummy + 0;
		dummy = dummy * 1;
		dummy = dummy / 1;
	  }
	 }
	}
}