ORG 0000H
LJMP MAIN
ORG 000BH
LJMP T0_INT
ORG 0100
MAIN:
MOV TMOD,#01H
MOV TH0,#0D8H
MOV TL0,#0F0H
MOV A,#00H
MOV P1,A
MOV R0,#20
SETB EA
SETB ET0
SETB TR0
LOOP: NOP
LJMP LOOP
T0_INT:
MOV TH0,#0D8H
MOV TL0,#0F0H
DJNZ R0,OUT
MOV R0,#20H
CPL A
MOV P1,A
OUT: RETI
END