5_3.txt

This are the Laboratory programs for the 89c51

;DEPENDING ON THE STATUS OF P2.0 GENERATE TWO PULSES OF DIFF FREQ ON P1.0
ORG 0000H
SJMP MAIN 
ORG 000BH
SJMP ISR
ORG 0030H
MAIN:
MOV TL0,#0CH
MOV TH0,#0FCH
SETB EA
SETB ET0
CLR P1.0
SETB TR0
ST:SJMP ST


ISR:
CLR TR0
JB P2.0,XXX
MOV TL0,#00CH
MOV TH0,#0FCH
SJMP YYY
XXX:
MOV TL0,#00CH
MOV TH0,#0FEH
YYY:
CPL P1.0
SETB TR0
RETI
END