// oh3nwq 25.2.2007
// 
// reads a 24 bit counter a nibble at a time 
// using parallel port

// work flow

// send 0 
// send 0x10 = latch enable 
// send 0
// send 1    = read 1st byte from counter to PIC 16F84 memory
// send 0
// send 2    = read 2nd byte from counter to PIC 16F84 memory
// send 0
// send 3    = read 3rd byte from counter to PIC 16F84 memory
// send 0
// send 4    = read 4th byte from counter to PIC 16F84 memory
// send 0

//LOOP send 13..6; 
//LOOP read nibble x from PIC 16F84 memory
//LOOP send 0


#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <asm/io.h>

#define wbase 0x378           /* printer port base address */
#define rbase 0x379           /* I/O address to read */

main(int argc, char **argv)
{
  int value,rvalue,inverted,nibble;
  int j;

   value = 0;
    
   if (ioperm(wbase,1,1))
    fprintf(stderr, "Couldn't get the port at %x\n", wbase), exit(1);

   outb(value, wbase);
			// start with 0

   if (ioperm(rbase,1,1))
    fprintf(stderr, "Couldn't get the port at %x\n", rbase), exit(1);

   
   value = 0x10;
   outb(value, wbase);
			// latch enable
   for (j=0;j<2000000;j++);
   value = 0x00;
   outb(value, wbase);
   for (j=0;j<2000000;j++);
			// latch disable

   value = 0x01;
   outb(value, wbase);
                        // read byte 1
   for (j=0;j<2000000;j++);
   value = 0x00;
   outb(value, wbase);
   for (j=0;j<2000000;j++);
                        // done

   value = 0x02;
   outb(value, wbase);
                        // read byte 2
   for (j=0;j<2000000;j++);
   value = 0x00;
   outb(value, wbase);
   for (j=0;j<2000000;j++);
                        // done


   value = 0x03;
   outb(value, wbase);
                        // read byte 3
   for (j=0;j<2000000;j++);
   value = 0x00;
   outb(value, wbase);
   for (j=0;j<2000000;j++);
                        // done

   value = 0x04;
   outb(value, wbase);
                        // read byte 4
   for (j=0;j<2000000;j++);
   value = 0x00;
   outb(value, wbase);
   for (j=0;j<2000000;j++);
                        // done

   printf("0x");  
  for (value=13;value>5;value--){
  outb(value, wbase);
  for (j=0;j<100000;j++);

  rvalue = inb(rbase);
  nibble = ((rvalue >> 3) & 0x0f);
    printf("%X", nibble);
  j=0;   
  outb(j, wbase);
  for (j=0;j<100000;j++);
  }

  printf("\n");
}