#include <16f877A.h>  
  #fuses HS,NOWDT,NOPROTECT,NOBROWNOUT,NOLVP,NOPUT,NOWRT,NODEBUG,NOCPD 
  #use delay (clock=20000000) 
  #use rs232(baud=9600,parity=N,xmit=pin_C6,rcv=pin_C7,bits=8,stop=1) 
  char c; 
   
  #int_rda 
  void seri() 
  { 
     disable_interrupts(int_rda); 
     c=getc(); 
     if(c=='1')             // TEK BIT VERI OKUMA 
     { 
        output_high(pin_d0); 
        output_low(pin_d1); 
     } 
     if(c=='2')  
     { 
        output_low(pin_d0); 
        output_high(pin_d1); 
        output_low(pin_d2); 
     } 
     putc(c);             // KONTROL AMACLI TEK BITI GERI GONDERME 
  } 
   
  void main() 
  { 
     set_tris_d(0x00); 
     output_d(0x00); 
     enable_interrupts(global); 
      
     while(true) 
     { 
        enable_interrupts(int_rda); 
     } 
  }