就下个亮 上个灭 每个亮一秒
ORG 0000H
LJMP MAIN
ORG 0030H
MAIN:
MOV TMOD,#01H
MOV TH0,#HIGH(65536-50000)
MOV TL0,#LOW(65536-50000)
SETB TR0
SETB EA
MOV R2,#20
MOV A,#0F0H
MOV P0,A
LP:
JNB TF0,$
CLR TF0
DJNZ R2,LP
CPL A
MOV P0,A
DJNZ R2,LP
MOV R2,#20
SJMP LP
END