MOV TMOD,#10H       ;timer 1, mode 1 (16-bit)
AGAIN:                  MOV TL1,#34H        ;TL1=34H,low byte of timer
                        MOV TH1,#76H        ;TH1=76H,HI byte
                                            ;(7634H=timer value)
                        SETB TR1            ;start the timer1
BACK:                   JNB  TF1,BACK       stay till timer rolls over
                        CLR TR1             ;stop timer 1
                        CPL P1.5            ;comp. p1.5 to get hi, lo
                        CLR TF1             ;clear timer flag 1
                        SJMP AGAIN          ;reload timer since mode 1
                                            ;is not auto-reload