/* 
 **********************************************************************
 * File  demo_ppi.C    -     Rel. 1.1  compile with  uC/51 V. 1.10.10 *
 * GRIFO(R)   via Dell'Artigiano 8/6   40016 S. Giorgio di Piano (BO) *
 * Cards: GPC(r) F2 d.s. 130688 and DEB01 or TIO16                    *
 *     Tel. +39 051 892052                      Fax. +39 051 893661   *
 *     http://www.grifo.com                     http://www.grifo.it   *
 *     sales@grifo.it         tech@grifo.it          grifo@grifo.it   *
 *     by Graziano Gaiba                                   29.09.03   *
 **********************************************************************

 Rel. 1.1 - 29.09.2003 by Graziano Gaiba

 Connect CN15 of DEB01 or CN1 of TIO16 through a 20 pins flat to CN3 
 of GPC(r) F2.

 This program allows to manage all the 24 TTL digital lines of PPI
 82c55, at the same time a sound indicates output setting.
*/

#include <reg52.h>
#include <stdio.h>
#include <ctype.h>

// Clock frequency of CPU used
#define FCLOCK              11059200

#define FALSE 0x00					   // Boolean values
#define TRUE 0xFF



// On board peripherals registers allocation addresses.
static unsigned char  	    PORTA   @ 0xFA00,
			    PORTB   @ 0xFA01,
			    PORTC   @ 0xFA02,
			    CNT     @ 0xFA03;

	
/********* General purpose utilities and hw sections management ***********/
void iniser(unsigned long baud)
/* Initialise serial port with:		Bit x chr   = 8
					Stop bit    = 1
					Parity	    = None
					Baud rate   = baud
   using timer 1 as baud rate generator.				   */
{
  SCON=0x052;					  // Modo 1, receiver enabled
  TMOD&=0x00F;				       // Timer 1 in auto-reload mode
  TMOD|=0x020;
  TR1=0;						      // Stop TIMER 1
  TH1=256-((2*FCLOCK)/(384*baud));		       // baud at 14.7456 MHz
  PCON=PCON|0x080;			   // Set SMOD=1 for higher baud rate
  TR1=1;						     // Start TIMER 1
}


// Wait for signals settling
void setup(void)
{
  unsigned int i;

  for(i=10000; i!=0; i--)
    ;
}


// Initialise 82c55 with value in parameter
void init8255(unsigned char c)
{
  CNT=c;
}


// Set port A of 82c55
void setPortA(unsigned char v)
{
  PORTA=v;
}


// Set port B of 82c55
void setPortB(unsigned char v)
{
  PORTB=v;
}


// Set port C of 82c55
void setPortC(unsigned char v)
{
  PORTC=v;
}


// Get port A of 82c55
unsigned char getPortA(void)
{
  return PORTA;
}


// Get port B of 82c55
unsigned char getPortB(void)
{
  return PORTB;
}


// Get port C of 82c55
unsigned char getPortC(void)
{
  return PORTC;
}


// Get value of DSW1
unsigned char getDSW1(void)
{
  return PORTB;
}


void ritardo(unsigned int rit)
/* Software delay of rit milliseconds, calibrated for 22.1184 MHz,
   according to the CPU installed.                                   */
{
unsigned int r;

  do
  {
    for (r=0 ; r<150 ; r++);
    rit--;
  }
  while (rit>0);
}


// Makes a short noise and performs about three seconds of total delay
void ritardo_bip(void)
{
  unsigned int i;

  // Sound of aboot 500 Hz of frequency lasting about 300 msec
  for(i=0; i<150; i++)
  {
    P1_B2=0;	// Turn on buzzer
    ritardo(1);
    P1_B2=1;    // Turn off buzzer
    ritardo(1);
  }

  ritardo(700);
}



// **************************** Main program *****************************

void main(void)
{
  unsigned char c;

  setup();                         // Wait for signals settling

  iniser(9600);
  TI=0;
  RI=0;

  // Comment next two lines if serial port is used in polling (SIOTYPE=p or k)
  ES=1;                                 // Enable serial port interrupt
  EA=1;					// Enable all interrupts

// Initialisation of PPI 8255.
  init8255(0x82);	        // PORT A and C in OUTPUT, PORT B in INPUT.

  puts("*************************** Demo PPI  ***************************");
  puts("");
  puts("This demo drives the shift activation of the lines of Port A and C available on");
  puts("connector CN2 and shows continuously the value of Port B, available on CN1.\n");

  for (;;)		           // Loop forever.
  {
    // Shift from red LEDs to yellow and green LEDs
    c=1;
    setPortC(0xff);                // Clears Port C
    while(c)
    {
      setPortA(~c);
      c<<=1;
      // Delay to make the movement of the LED visible
      ritardo_bip();
      printf("%X\r", getPortB());
    }
    c=1;
    setPortA(0xff);                // Clears Port A
    while(c)
    {
      setPortC(~c);
      c<<=1;
      // Delay to make the movement of the LED visible
      ritardo_bip();
      printf("%X\r", getPortB());
    }


    // Shift from yellow and green LEDs to red LEDs
    c=0x80;
    setPortA(0xff);                // Clears Port A
    while(c)
    {
      setPortC(~c);
      c>>=1;
      // Delay to make the movement of the LED visible
      ritardo_bip();
      printf("%X\r", getPortB());
    }
    c=0x80;
    setPortC(0xff);                // Clears Port A
    while(c)
    {
      setPortA(~c);
      c>>=1;
      // Delay to make the movement of the LED visible
      ritardo_bip();
      printf("%X\r", getPortB());
    }
  }			  			  	 
}