/*
   FILE: 7266_03.C
   DATE: 07/26/99 - 1.0
	 05/16/00 - 2.0 started - WORKS!
	 05/17/00 - 13:10 3.0 started - WORKS!
   AUTH: P.OH
   DESC: Testing prototyped 7266 card.  Code based on US Digital's
	 sample.c file and Tom Kulaga's txt_dro.cpp
	 Added some things like, DEGREEs printout
	 3.0: rewrite things as I understand it
*/

#include <stdio.h>
#include <dos.h>
#include <conio.h>
#include <process.h>

/* LS7266 commands */
#define CLOCK_DATA 	14	/* FCK frequency divider                */
#define CLOCK_SETUP 	0X98	/* transfer PR0 to PSC (x and y)        */
#define INPUT_SETUP     0XC1	/* enable inputs A and B (x and y)      */
#define QUAD_X1         0XA8	/* quadrature multiplier to 1 (x and y) */
#define QUAD_X2         0XB0	/* quadrature multiplier to 2 (x and y) */
#define QUAD_X4         0XB8	/* quadrature multiplier to 4 (x and y) */
#define BP_RESET    	0X01	/* reset byte pointer                   */
#define BP_RESETB  	0X81	/* reset byte pointer (x and y)         */
#define CNTR_RESET      0X02	/* reset counter                        */
#define CNTR_RESETB     0X82	/* reset counter (x and y)              */
#define TRSFRPR_CNTR    0X08	/* transfer preset register to counter  */
#define TRSFRCNTR_OL	0X90	/* transfer CNTR to OL (x and y)        */
#define EFLAG_RESET	0X86	/* reset E bit of flag register         */

#define SLOTS_ON_DISK   500     /* US Digital's encoder S1-500-INT encoder */

/* prototypes */
void initialize7266(int, int, int);
long xReadEncoder(int, int);
void xPrintValue(long, int);

void main(void) {

  long xEncoderValue;
  int quadrature, desiredQuadrature;
  int BASEADDR;
  int xControl, xData;

  clrscr();
  window(5,5,75,30);
  gotoxy(1,1);
  cprintf("Enter base address (decimal) e.g. 608\n");
  gotoxy(1,2); scanf("%d", &BASEADDR);

  xData =    BASEADDR;
  xControl = BASEADDR + 1;

  gotoxy(1,3);
  cprintf("Desired quadrature: 1 (single), 2 (double), 4 (quad) e.g. 1\n");
  gotoxy(1,4); scanf("%d", &desiredQuadrature);
  switch (desiredQuadrature) {
	case 1 : quadrature = QUAD_X1; break;
	case 2 : quadrature = QUAD_X2; break;
	case 4 : quadrature = QUAD_X4; break;
  }

  gotoxy(1,5); cprintf("Initializing...");
  initialize7266(quadrature, xControl, xData);
  cprintf("...done\n");
  gotoxy(1,7); cprintf("Spin encoder or hit a key to quit\n");

  while (!kbhit()) {
    outportb(xControl, TRSFRCNTR_OL); /* transfer CNTR to OL */
    xEncoderValue = xReadEncoder(xControl, xData);
    xPrintValue(xEncoderValue, desiredQuadrature);
 }
} /* end of main */

void initialize7266(int quadrature, int xControl, int xData) {

  /* initialize the 7266 */

  int fail = 0;

  outportb(xControl, EFLAG_RESET); /* reset E bit of flag register */
  outportb(xControl, BP_RESETB); /* reset byte pointer */
  outportb(xData, CLOCK_DATA); /* FCK freq divider */
  outportb(xControl, CLOCK_SETUP); /* transfer PR0 to PSC */
  outportb(xControl, INPUT_SETUP); /* enable inputs A and B */
  outportb(xControl, quadrature); /* desired quadrature e.g. 1, 2 or 4 */
  outportb(xControl, CNTR_RESETB); /* reset counter */

  /* preset values to the X-axis preset register */
  outportb(xControl, BP_RESET); /* reset byte pointer  */
  outportb(xData, 0x12); /* output preset value */
  outportb(xData, 0x34);
  outportb(xData, 0x56);

  /* read counter back to test it */
  outportb(xControl, TRSFRPR_CNTR); /* transfer preset to counter */
  outportb(xControl, TRSFRCNTR_OL); /* transfer CNTR to OL */
  outportb(xControl, CNTR_RESET); /* reset counter */

  outportb(xControl, BP_RESET); /* reset byte pointer */

  /*
   if all goes well, then the 3 output preset values should
   read back the same 3 values.  If not then fail variable is incremented
   and initialize7266 failure message is printed.
  */

  if (inportb(xData) != 0x12) fail++;
  if (inportb(xData) != 0x34) fail++;
  if (inportb(xData) != 0x56) fail++;
  if (fail) {
    printf("initialize7266 failed\n");
    exit(0);
  };
  return;
} /* end of init */

long xReadEncoder(int xControl, int xData) { /* read position of X encoder */

 long position;

 outportb(xControl, BP_RESETB);	/* reset byte pointer */

 /* read 3 consecutive bytes and add them */
 position  = (long)inportb(xData); /* least significant byte */
 position += (long)inportb(xData) << 8;
 position += (long)inportb(xData) <<16;	/* most significant byte  */

 return position;
} /* end of xReadEncoder */

void xPrintValue(long xEncoderValue, int desiredQuadrature) {

  /* print X encoder value */
  /* NB: 2^24 = 16777216 */

  float degreesPerPulse = 360.0/SLOTS_ON_DISK/desiredQuadrature;

  gotoxy(5,15);
  cprintf("Value   = %7lX (HEX) = %10ld (DECIMAL)", xEncoderValue, xEncoderValue);
  gotoxy(5,17);
  cprintf("Pulses  = %10ld", (16777216-xEncoderValue) );
  gotoxy(5,18);
  cprintf("Degrees = %10.3f", (16777216-xEncoderValue)*degreesPerPulse);

} /* end of xPrintValue */