ORG 0000H
       jmp st

ST:    CLR P3.3
       MOV A,#0FEH
       MOV R1,#08H
       MOV R2,#08H
       MOV R3,#08H
ST0:   MOV P0,A
       RL A
       ACALL DELAY
       DJNZ R1,ST0
       MOV A,#0FEH
ST1:   MOV P1,A
       RL A
       ACALL DELAY
       DJNZ R2,ST1
       MOV A,#0FEH
ST2:   MOV P2,A
       RL A
       ACALL DELAY
       DJNZ R3,ST2
       SETB P3.3
SHT:   MOV A,#01H
       MOV R1,#08H
       MOV R2,#08H
       MOV R3,#08H
SHT0:  MOV P0,A
       RL A
       ACALL DELAY
       DJNZ R1,SHT0
       MOV A,#01H
SHT1:  MOV P1,A
       RL A
       ACALL DELAY
       DJNZ R2,SHT1
       MOV A,#01H
SHT2:  MOV P2,A
       RL A
       ACALL DELAY
       DJNZ R3,SHT2
       LJMP ST

DELAY: MOV R6,#90H
H1 :   MOV R7,#0FFH
H2:    DJNZ R7,H2
       DJNZ R6,H1
       RET
       END