/*****************************************************
Project : PT2272 series Simulator
Version : 1.0
Date    : 2006/10/28
Author  : behzad khazama                            
Company : www.khazama.com                            
Comments: finally implemented at 1385/08/06 -- 04:43AM IRAN - SABZEVAR       
Chip type           : ATmega32
Clock frequency     : 12.000000 MHz

Some Important Notice about Calibration.     
  with a 2.2Mega OHM Oscillator Calibrator risistor 
  used with PT2262(Pin 15,16) ,
  -> Timer1 overflow must trigger every 120us.
  see Timer1 overflow routin for more.

  THIS Project is AS-IS and FREE to USE and FREE to Modify.
  BUT Please put my sites link into your projects that use this code.
  and finally I Implement this code very rush and it maybe have some BUGs.  
  SO : ANY BUGs OR SUGGESTIONs ARE WELCOME.

  Pin connections:
	INPUT Code(insted DIN of PT2272) is "INT0 PORTD.2"
	LCD 2*16 -> PORTA as discribed on CodevisionAvr	
	

  Fell Free and contact me by :
   my contact Number : +98-09155714862
   or via eMail       : behzad@khazama.com
*****************************************************/

#include <mega32.h>
#include <delay.h>
// Standard Input/Output functions
#include <stdio.h>

// Alphanumeric LCD Module functions
#asm
   .equ __lcd_port=0x1B ;PORTA
#endasm
#include <lcd.h>

// Declare your global variables and FUNCTIONS here
extern void init(void);
unsigned char edge=1;
unsigned int HTime=0,LTime=0 ;
unsigned long Tm=0;
unsigned char bufer[13];
unsigned char Tmp[24];
unsigned char DetectTruePacket=0;

#pragma warn-
void FinalAnalyse(void){
 unsigned char i=0;
 for(i=0;i<12;i++){
    if     (Tmp[i*2]==0 && Tmp[(i*2)+1]==0){
        bufer[i]='0';
    }
    else if(Tmp[i*2]==1 && Tmp[(i*2)+1]==1){             
        bufer[i]='1';    
    }
    else{
        bufer[i]='F';        
    }
 };  
 bufer[12]=0; // terminate string 
}
#pragma warn+

unsigned char isSync(void){
 if (HTime<LTime)
    if(HTime>13 && HTime<30)
     if(LTime>570 && LTime<700)
         return(1);            
 return(0);     
}

unsigned char isZero(void){
 if (HTime<LTime)
    if(HTime>13 && HTime<30)
     if(LTime>50 && LTime<70)
         return(1);            
 return(0);     
}

unsigned char isOne(void){
 if (HTime>LTime)
    if(LTime>13 && LTime<30)
     if(HTime>50 && HTime<70)
         return(1);            
 return(0);     
}

// Timer 1 overflow interrupt service routine
interrupt [TIM1_OVF] void timer1_ovf_isr(void)
{
 /* TCNT1 = 0xFF9B that mean 65535-100 
  so this routin will trigger every 120us on 12MHZ.  
  if your project is using different clock rate 
  u must modify TCNT1 rigisters to project work fine.*/
  
 TCNT1H=0xFF;
 TCNT1L=0x9B;
 Tm++;   
}

// External Interrupt 0 service routine
interrupt [EXT_INT0] void ext_int0_isr(void)
{
  static unsigned char bitCnt=0;    
    if(edge>0){
         LTime=Tm;
         Tm=0;
         MCUCR = 2;            // Set interrupt on falling edge
         edge = 0;
         if(isSync()){
          if(bitCnt==24){ 
            FinalAnalyse() ;
            DetectTruePacket=1;
          };
          bitCnt=0;

         } else if(isZero()){
          Tmp[bitCnt++]=0;

         } else if(isOne()){
          Tmp[bitCnt++]=1;         

         } else{
          bitCnt=0;
         }
    }else{       
         HTime=Tm;
         Tm=0;
         MCUCR = 3;            // Set interrupt on rising edge
         edge = 1;      
    };
}


void main(void)
{
init();
lcd_init(16);
#asm("sei")

while (1)
      {
      if(DetectTruePacket){
           lcd_gotoxy(0,0);     
           lcd_puts(bufer);     
           DetectTruePacket=0;
      };
      };
}