High or low state are identify by the length of the infrared signal.

 stateH: mov     r1,#100  

             acall   highled

             mov     r1,#50                                                                                                            

            acall   lowled                                                                                                           ret                                                                                                                                    stateL: mov     r1,#50                                                                                                     acall   highled                                                                                                               mov     r1,#50                                                                                                                  acall   lowled                                                                                                                           ret

                                                                                                              ret