/*****************************************************************************
 *                          MODULE: SAMPLE8.C                                *
 *                                                                           *
 *  This sample program will sequentially turn on all bits in port a and then*
 *  seqentially turn them off.  Each time it sets a new bit, both port a and *
 *  port b are read and the data displayed.  This demonstartaes how to read  *
 *  and write to a port, and to use the read back function of the 8255 chip. *
 *  If the port a pins are jumpered to the port b pins, then a board test    *
 *  program results, with port b being used to verify what has been written  *
 *  to port a.  The program will use port 0 of cards with mulitple 8255's.   *
 *                                                                           *
 *****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <sys/io.h>
#include <ctype.h>

unsigned int Address; /* assign Base Address to variable */

/* this typedef allow use to duplicate the boolean type as used in pascal */

typedef enum {FALSE,TRUE} boolean;

void IOPermission(unsigned abase) {
  if(ioperm(abase,32,1)<0)
  {
     fprintf(stderr, "NO IO PERMISSION\n");
  }
}

unsigned AskForBaseAddress(unsigned int OldOne)
{
	char msg[3];
	unsigned int newone;
        unsigned int temp = 0;
        int index = 0;        
	int letter;

	puts("Please enter the Base Address for your card (in hex)");
 	printf("or press ENTER for %X.\n>", OldOne); 
        while(temp==0)
        {  
          newone=0;
          index=0; 
          while((letter = getchar())!='\n')
          msg[index++] = letter;
          sscanf(msg, "%X", &newone);
          if(newone==0){
            temp=OldOne;
 	  } else if((newone>=0x100)&&(newone<=0x3f0)){
	    temp=newone;
          } else {
             printf("\nEnter the Base Address or press ENTER for %x > ", OldOne);
             for(index=0; index<=3; index++)
              msg[index]=0;
	  }
        } 
        return(temp);
} /* end of AskForBaseAddress */



/*****************************************************************************
 *  FUNCTION: signon -- local routine                                        *
 *                                                                           *
 *   PURPOSE: To display an initial sign on message on the screen.           *
 *                                                                           *
 *     INPUT: None.                                                          *
 *                                                                           *
 *    OUTPUT: None.                                                          *
 *                                                                           *
 *****************************************************************************/
void signon()
{
  int	  clear;

  system("clear"); 
  printf(
   "                     8255 Digital I/O Sample Program                      \n"
   "This sample program will sequentially turn on all bits in port a and then \n"
   "seqencially turn them off.  Each time it sets a new bit, both port a and  \n"
   "port b are read and the data displayed.  This demonstrates how to read    \n"
   "and write to a port, and to use the read back function of the 8255 chip.  \n"
   "If the port a pins are jumpered to the port b pins, then a board test     \n"
   "program results, with port b being used to verify what has been written   \n"
   "to port a.  The program will use port 0 of cards with mulitple 8255's.    \n");

   /* print the string display and ask for the base address */
  
   Address=AskForBaseAddress(0x340);
   IOPermission(Address);
   system("clear");  
   puts("Board Configuration:\n");
   printf(" -- Base Address is %X hex\n",Address);
   printf(" -- Connect a loopback cable from PORT A to PORT B of PPI0. (required)\n");
   printf("PRESS ENTER TO CONTINUE");
   while((clear=getchar())!='\n');
   system("clear");
   printf(" PORT A OUTPUT     PORT A INPUT      PORT B INPUT \n");
   printf(" -------------     ------------      ------------ \n");
   system("tput cup 27 10");
   puts(" PRESS ANY KEY TO EXIT PROGRAM ");
} /* end signon */

/*****************************************************************************
 *  FUNCTION: write_port_data -- local routine                               *
 *                                                                           *
 *   PURPOSE: Displays the current port values on the screen.                *
 *                                                                           *
 *     INPUT: current: array with the port reading to display.               *
 *                                                                           *
 *****************************************************************************/
void write_port_data(unsigned char current[3])
{
   unsigned      index1,index;
   unsigned char value;
   int i;

   i=1;
   system("tput cup 0 0 ");
   /* x coordinate to write value to screen */
   for (index = 0;index <= 2;index++)       /* for each array member */
      {
      value = current[index];  
      if (i==1) { system("tput cup 1 3"); i++; } else if (i==2) { system("tput cup 1 21"); i++; } else if (i==3) { system("tput cup 1 39"); }
      for (index1 = 0;index1 <= 7;index1++) /* for each bit in array member */
         {
         if (value % 2) putchar('1');
         else putchar('0');
         value = value >> 1;                /* roll next diaplay bit */
         }
      puts("\n");
      }
}  /* end write_port_data */

int main()
{
   unsigned char           current[3];
   boolean		   shift_left;
   //  int                     clear;
   int  x=0;

   signon();   
   outb(0x8b,Address+19);        /* send the control byte              */
   current[0] = 0;
   shift_left = TRUE;
   do
      {
      outb(current[0],Address+16);     /* write value to port a              */
      current[1] = inb(Address+16);    /* read back what we wrote to port A  */
      current[2] = inb(Address+17);    /* read the data on port B            */
      write_port_data(current);       /* write new data to screen           */
      x++; 
      system("sleep 1");
      /* compute value to turn on/off nesxt bit in line */
      if (current[0] == 0) shift_left = TRUE;
      if (current[0] == 255) shift_left = FALSE;
      if (shift_left) current[0] = (current[0] << 1) + 1;
      else current[0] = (current[0] - 1) >> 1;
      }while(x!=5);

   return 0;
} /* end main program */