/*****************************************************************************
 * ECE476 Final Lab - Stepper Motor Test Program                             *
 * David Shu (dhs25)                                                         *
 * Thientu Ho (th243)                                                        *
 * 4/05                                                                      *
 *****************************************************************************/

/* 
 * Ports
 * ~~~~~
 * PORTA : 
 * PORTB : [output] Output to motor control
 * PORTC : [output] Debug LED's
 * PORTD : 
 *
 */

#include <Mega32.h>
#include <Stdio.h>
#include <Stdlib.h>

// ### DEFINITIONS ############################################################
// Time definitions
#define t0		10

// Wire definitions
/* BLUE		1011
 * ORANGE	1110
 * RED		1101
 * WHITE	0111
 */
#define STEP0	0b00000110
#define STEP1	0b00001010
#define STEP2	0b00001001
#define STEP3	0b00000101

void initialize(void);

// Timer used for counting 1 ms
unsigned int	time_step;
// Used for counting the number of steps
unsigned char	step;

// ### ISRs ###################################################################
interrupt [TIM0_COMP] void isr_onems(void) {
	if (time_step>0) time_step--;
}	// end isr_onems

// ### INITIALIZE #############################################################
void initialize(void) {
	// PORTB : [output] Output to motor control
	DDRB	= 0xff;
	PORTB	= 0;

	// PORTC : [output] Debug LED's
	DDRC	= 0xff;
	PORTC	= 0xff;

        // Set up Timer0, 1 ms
        TIMSK = 2;                      // t0 compare match enable
        OCR0 = 249;                     // 250 ticks until clear
        TCCR0 = 0b00001011;             // CTC, clk/64
          
	// Initialize counters
//	time_step = t0;
	step = 0;
      
	#asm
		sei
	#endasm
}	// end initialize()

// ### MAIN ###################################################################
void main(void) {
	initialize();

	while(1) {
		if (time_step == 0) {
			time_step = t0;

			if (step < 3) step++;
			else step = 0;
		}


		if (step == 0) {
			PORTB = STEP0;
			PORTC = ~STEP0;
		}	// end step 0

		if (step == 1) {
			PORTB = STEP1;
			PORTC = ~STEP1;
		}	// end step 1

		if (step == 2) {
			PORTB = STEP2;
			PORTC = ~STEP2;
		}	// end step 2

		if (step == 3) {
			PORTB = STEP3;
			PORTC = ~STEP3;
		}	// end step 3

	}	// end while(1)
}	// end main