library

/****************************************
***** RC5 Protocol Counter **************
***** with special recognition RC5 ******
***** AT90S2313 4MHz ********************
***** 08/2005****************************
****************************************/

#include <90s2313.h> 

void PortInit(void);
void Delay(unsigned long int time); 

const unsigned char ir=64;                     //PD.6 je vstup IR signalu 

const unsigned char timer=46;                // 0,25 * bit = 0,4193325ms

/*merenim sem stanovil periodu jednoho bitu na 1,67733ms*/

unsigned char flag=1;                          //priznak prijmu signalu RC5
unsigned char ct=0;                            //pomocny citac 
unsigned char s[3]={0,0,0};         //vzorky start bitu pro presne urceni ramce rc5
unsigned char adr=0;                            //adresa prijimanych dat
unsigned char data=0;                           //data
unsigned char togg=0;                           //toggle bit

void main (void){
  PortInit();
  SREG|=128;                                    //vsechna prerus
  TIMSK|=2;                                     //prerus overflow ct0
  TCNT0=timer;
  
  for(;;){
  
    while((PIND&ir)==ir){}                //cekej na spadovou hranu - 1 start bit
    
    TCCR0|=2;                                   //zap ct0 + ck/8
    ct=0; flag=1;
    while(flag){}                               //cekej na konec prijmu
    TCCR0=0;                                    //vyp ct0
    TCNT0=timer;                                //znova nastavi dany interval
    Delay(1000); 
    
    if((s[0]==0)&(s[1]==1)&(s[2]==0)){PORTB=data;} //splnena startovaci podminka RC5
    
    }
}                                               
//***** Preruseni CT0 ****************************************************************
//prijem signalu
interrupt [TIM0_OVF] void timer0_overflow(void){
  TCNT0=timer;
  
  switch (ct++) {
    case 0: if((PIND&ir)==ir){s[0]=1;}else{s[0]=0;} break;  // 3/4 1.start bitu = 0
    case 2: if((PIND&ir)==ir){s[1]=1;}else{s[1]=0;} break;  // 1/4 2.start bitu = 1
    case 4: if((PIND&ir)==ir){s[2]=1;}else{s[2]=0;} break;  // 3/4 2.start bitu = 0
    
    /*case 6: if((PIND&ir)==ir){togg=1;}else{togg=0;} break;
    
    case 10: if((PIND&ir)==ir){adr|=16;}else{adr&=255-16;} break;
    case 14: if((PIND&ir)==ir){adr|=8;}else{adr&=255-8;} break;
    case 18: if((PIND&ir)==ir){adr|=4;}else{adr&=255-4;} break;
    case 22: if((PIND&ir)==ir){adr|=2;}else{adr&=255-2;} break;
    case 26: if((PIND&ir)==ir){adr|=1;}else{adr&=255-1;} break; */
    
    case 30: if((PIND&ir)==ir){data|=32;}else{data&=255-32;} break; 
    case 34: if((PIND&ir)==ir){data|=16;}else{data&=255-16;} break;
    case 38: if((PIND&ir)==ir){data|=8;}else{data&=255-8;} break;
    case 42: if((PIND&ir)==ir){data|=4;}else{data&=255-4;} break;
    case 46: if((PIND&ir)==ir){data|=2;}else{data&=255-2;} break;
    case 50: if((PIND&ir)==ir){data|=1;}else{data&=255-1;} flag=0; break;
    // co 4 preruseni je teprve cely bit
    }  
}
//***** Zpozdovaci procedura *********************************************************
void Delay(unsigned long int time) {
  unsigned int j=0;
  for (j=0;j<time;++j) {};
}
//***** Nastaveni portu **************************************************************
void PortInit(void){
  DDRB=255;  PORTB=0;                           //vystup + log0
  DDRD=0;  PORTD=ir;                            //vstupy + na ir pullup
}