LJMP MAIN
ORG 000BH
LJMP T0ISR
ORG 0030H
MAIN:
MOV TMOD,#01H
MOV TH0,#HIGH(65536-50000)
MOV TL0,#LOW(65536-50000)
SETB TR0
SETB ET0
SETB EA
MOV R2,#0
MOV R3,#6
MOV R4,#0FEH
CLR 00H
SJMP $
T0ISR:
CLR TR0
MOV TH0,#HIGH(65536-50000)
MOV TL0,#LOW(65536-50000)
SETB TR0
INC R2
CJNE R2,#20,T0E
MOV R2,#0
JB 00H,T0LS
MOV A,P0
CPL A
MOV P0,A
DJNZ R3,T0E
SETB 00H
SJMP T0E
T0LS:
MOV A,R4
MOV P0,A
RL A
MOV R4,A
T0E:
RETI
END