DELAY2: ;PC7口置1，8253开始工作
PUSH DX
PUSH AX
MOV AL,00001111B
MOV DX,io8255_CTL
OUT DX,AL
POP AX
POP DX
MOV BL,00000000B
MOV CX,0FFFFH ;延时一段时间后，8253停止工作
call daily
PUSH DX
PUSH AX
MOV AL,00001110B ;PC7口置0，8253停止工作
MOV DX,io8255_CTL
OUT DX,AL
POP AX
POP DX
daily:
mov cx,2000H
D0:mov ax,0FFFFH
D1:dec ax
jz D1
loop D0
daily endp
