/***********************************************************************
 * upDown.cpp
 *
 * Driver program for up/down counter project.
 *
 * This program assumes the following:
 *
 *    Parallel port pin             FPGA signal
 *    --------------------          ------------
 *    D0                            Reset
 *    D1                            Hold
 *    D2                            Up/!Down
 *
 * The program allows the user to control the above three parallel port
 * pins from the keyboard:
 *
 *    Key                           Action
 *    --------------------          -------------------------------
 *    r                             Toggle D0.
 *    h                             Toggle D1.
 *    c                             Toggle D2.
 *    q                             Exit.
 *
 * "Enter" must be pressed after a keystroke.
 *
 * This program will first reset the counter, then begin counting up.
 *
 * For compilation, this program requires pport.h and pport.cpp.
 ***********************************************************************/


#include <stdio.h>
#include "pport.h"


/***********************************************************************
 * main()
 ***********************************************************************/

int main()
{
   /* Current values of the parallel port's data pins. */
	int reset = 1;
	int hold = 0;
	int count = 1;

	/* Reset counter */
	writeDataReg(0x4);
   /* Begin counting up. */
	writeDataReg(0x5);

   /* Print simple instructions. */
	printf("Press 'r' to toggle reset, 'h' to toggle hold, or 'c' to"
          " toggle count\n");
	printf("direction.  Press 'q' to quit.\n\n");

   /* Action loop.  We read a keystroke, act on it, and wait for the next
    * keystroke.
    */

	while (1)
	{
		printf("\rReset: %d, Hold: %d, Count Direction: %d."
             "  Command: ", reset, hold, count);

		switch (getchar())
		{
		case 'r' :
      case 'R' :
			reset = (reset + 1) % 2;
			break;

		case 'h' :
      case 'H' :
			hold = (hold + 1) % 2;
			break;

		case 'c' :
      case 'C' :
			count = (count + 1) % 2;
			break;

		case 'q' :
      case 'Q' :
			printf("\n");
			return 0;
			break;

		default :
			break;
		}

      /* Write new values to parallel port. */
		writeDataReg((reset) | (hold << 1) | (count << 2));
	}

	return 0;
}