#include "Xbus.h"
#include <reg51.h>
#include <stdlib.h>

#define ZERO 0x77
#define ONE 0x12
#define TWO 0x5d
#define THREE 0x5b
#define FOUR 0x3a
#define FIVE 0x6b
#define SIX 0x6f
#define SEVEN 0x52
#define EIGHT 0x7f
#define NINE 0x7b
#define ERROR 0x6d

void PCReset()
{
	IE = 0x00; /* no interrupts */
	P0 = 0xff; /* tristate (not pull down) the port */
	P1 = 0xff; /* tristate (not pull down) the port */
	P2 = 0xff; /* tristate (not pull down) the port */
	P3 = 0xff; /* tristate (not pull down) the port */
}

// Pins for debugging
sbit NOSRAM = 0xB0;   /* error pin is P3.0 */
sbit SRAM = 0xB2;   /* noerror pin is P3.2 */
sbit DONE = 0xB3;   /* noerror pin is P3.3 */

void main()
{
	 unsigned char value = 0x01;
	 unsigned char back = 0x00;
     long i;
	PCReset();
	XInit();
	NOSRAM = 0; 
	SRAM = 0;
	DONE = 0;

	value = ZERO;
     while (1) { // all programs run forever
       XWrite(0x7fff, value);  // write new data to the led

	   back = XRead(0x7fff);	//read back the data
	   if(back != value) {
	   		value = ERROR;
		}
		else {
			switch (back) {
	   		case ZERO:
				value = ONE;
				break;
			case ONE:
				value = TWO;
				break;
			case TWO:
				value = THREE;
				break;
			case THREE:
				value = FOUR;
				break;
			case FOUR:
				value = FIVE;
				break;
			case FIVE:
				value = SIX;
				break;
		    case SIX:
				value = SEVEN;
				break;
			case SEVEN:
				value = EIGHT;
				break;
			case EIGHT:
				value = NINE;
				break;
			case NINE:
				value = ZERO;
				break;
			}
		}
	   
       for (i=0; i < 20000; i++); // wait 
     }
}