4_2.txt

This are the Laboratory programs for the 89c51

;GENERATE PULSE OF D=70% ON P1.0
ORG 0000H
SETB P1.0
MOV TMOD,#10H
BACK:MOV TL1,#44H
MOV TH1,#0FDH
SETB TR1
XXX: JNB TF1 ,XXX
CLR TR1
CLR TF1
CPL P1.0
MOV TL1,#0D4H
MOV TH1,#0FEH
SETB TR1
YYY: JNB TF1 ,YYY
CLR TR1
CLR TF1
CPL P1.0
SJMP BACK
END