serin2 komutu çalışmayı engelliyor

@   device  pic12f675, intrc_osc_noclkout, wdt_on, pwrt_on, mclr_off, protect_off           
           cmcon = %00000111 
           ansel = 0 
           OPTION_REG.7=0 
           trisio = %111101 
            
           SYMBOL CIKIS=GPIO.1 
           SYMBOL TUS=GPIO.0 
             gpio=0  
              BILGI VAR Byte 
               
              PAUSE 200 
  BASLA: 
  BILGI=0 
      IF TUS=0 then 
      BILGI=1 
      GOSUB GONDER 
      WHILE TUS=0 :WEND 
      ENDIF 
             PAUSE 100 
             GOTO BASLA 
   
  GONDER: 
        serout2 CIKIS,396,[REP$AA\5,REP$00\5,REP$FF\5]  
        serout2 CIKIS,396,[("O"),("Z"),("B"),BILGI] 
        serout2 CIKIS,396,[("O"),("Z"),("B"),BILGI] 
        serout2 CIKIS,396,[("O"),("Z"),("B"),BILGI] 
          return 
  END

@   device  pic12f675, intrc_osc_noclkout, wdt_on, pwrt_on, mclr_off, protect_off 
           cmcon=%00000111 
           ansel=0 
           trisio=%000110 
           GPIO=0 
          BILGI VAR Byte 
          GIRIS VAR GPIO.1 
          LED VAR GPIO.0 
          TUS VAR GPIO.2 
          PAUSE 100         
  BASLA: 
  serIN2 GIRIS,396,1,ZAMAN,[WAIT ("OZB"),BILGI] 
      IF BILGI=1 then 
      TOGGLE LED 
      PAUSE 50 
      ENDIF 
  ZAMAN: 
      IF TUS=0 THEN 
      TOGGLE LED 
      WHILE TUS=0 :WEND 
      PAUSE 50 
      ENDIF 
      GOTO BASLA 
      END