/*
   FILE: 3SQWAVE.C
   DATE: 03/18/99
   AUTH: P.OH. Boondog Automation
   DESC: Counters are programmed in Mode 3 square wave
         User enters in desired counter and frequency between 16 Hz and 500 kHz
*/

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

#define crystalValue 1000000
#define TRUE  1
#define FALSE 0

void main(void) {

  int baseAddress;
  int counter0, counter1, counter2, counter, counterNumber;
  int CNTRL;
  int gateAddress, gateNumber, gateValue, gateOn;

  long freq;   /* thus freq is a 32-bit value ranging from 0 to  4.2E9 */
  long actFreq;
  unsigned int counterValue;  /* counterValue ranges from 0 to 65535 */
  int validChoice;

  window(5,5,75,30);
  clrscr(); gotoxy(1,1);
  cprintf("Base Address is assumed to be 608 decimal\n");

  baseAddress = 608;
  counter0    = baseAddress;
  counter1    = baseAddress + 1;
  counter2    = baseAddress + 2;
  CNTRL       = baseAddress + 3;
  gateAddress = baseAddress + 4;
  gateOn      = FALSE;

  /* setup all counters for Mode 3 square wave, LSB then MSB loading */
  /* Counter 0 Binary word: 00 11 011 0 = 54 d */
  /* Counter 1 Binary word: 01 11 011 0 = 118 d */
  /* Counter 2 Binary word: 10 11 011 0 = 182 d */

  outportb(CNTRL, 54);  /* counter 0 */
  outportb(CNTRL, 118); /* counter 1 */
  outportb(CNTRL, 182); /* counter 2 */

  do
    {
       gotoxy(1,4); cprintf("Select a counter: \n");
       gotoxy(1,5); cprintf("(0) Counter 0\n");
       gotoxy(1,6); cprintf("(1) Counter 1\n");
       gotoxy(1,7); cprintf("(2) Counter 2\n");
       gotoxy(20,4); scanf("%d", &counter);

       switch(counter) {
	case 0 : /* counter 0 */
		 counter = counter0;
		 validChoice = TRUE;
		 gateValue = 1; /* set gate0 bit on */
		 gateNumber = counterNumber = 0;
		 break;
	case 1:  /* counter 1 */
		 counter = counter1;
		 validChoice = TRUE;
		 gateValue = 2; /* set gate1 bit on */
		 gateNumber = counterNumber = 1;
		 break;
	case 2: /* counter 2 */
		 counter = counter2;
		 validChoice = TRUE;
		 gateValue = 4; /* set gate0 bit on */
		 gateNumber = counterNumber = 2;
		 break;
	default: /* invalid choice */
		 gotoxy(1,2); cprintf("Must choose 0, 1 or 2 !!\n");
		 validChoice = FALSE;
		 break;
	}; /* end of switch */

     } while(!validChoice);

  /* frequency calculations */
  do {
     gotoxy(1,16);
     cprintf("Enter an integer frequency between 16 to 500000 Hz: ");
     scanf("%ld", &freq);
     gotoxy(1,17); cprintf("Type 0 to quit or 1 to toggle gate\n");

     if( freq > 1 )
	{
	   /* calculate values to load into counter */
	   counterValue = (unsigned int)(crystalValue / freq);
	   actFreq = (long)(crystalValue/counterValue);

	   /* load LSB first then MSB second */
	   outportb(counter, counterValue & 0x00FF);
	   outportb(counter, counterValue >> 8 );
	   outportb(gateAddress, gateValue);
	   gateOn = TRUE;
	}
     else if( freq == 1)
	{
	     if(gateOn) { /* then toggle off */
		 outportb(counter, 0 & 0x00FF);
		 outportb(counter, 0 >> 8);
		 outportb(gateAddress, 0);
		 gotoxy(1,22); cprintf("gate %d is turned off\n", gateNumber);
		 gateOn = FALSE;
	     }
	    else { /* then gate was off, so toggle on */
		 outportb(counter, counterValue & 0x00FF);
		 outportb(counter, counterValue >> 8);
		 outportb(gateAddress, gateValue);
		 gotoxy(1,22); cprintf("gate %d is turned on \n", gateNumber);
		 gateOn = TRUE;
	     }
	}
	gotoxy(53,16); cprintf("         ");  /* clear input field */
	gotoxy(1,12);
	cprintf("Counter %d Freq:     Desired = %ld Hz,     Actual = %ld Hz\n", counterNumber, freq, actFreq);
	gotoxy(1,15); cprintf("Enter another frequency if you want\n");

     } while (freq != 0 );

  clrscr();
  cprintf("Finished! Turning off gates\n");
  outportb(gateAddress, 0); /* turn off gate */

} /* end of main */