1.asm

来自「利用WAVE仿真集成开发系统建立、编译、执行和调试实验程序。 通过8255实现」· 汇编 代码 · 共 45 行

mode  equ  082h   ; 方式0，PA，PC输出，PB输入
       PortA equ  8000h  ; Port A
       PortB equ  8001h  ; Port B
       PortC equ  8002h  ; Port C
       CTL8255 equ  8003h  ; 控制字地址
  assume cs:code,ds:data
data segment
led db 24h,44h,04h,44h,04h,44h,04h
     db 81h,81h,81h,82h,80h,82h,80h,82h,80h
     db 0ffh
data ends
code   segment
Start:
    mov   ax,data
	mov ds,ax
	mov ax,80h
mov dx,CTL8255
out   dx, al       ; 输出控制字
re_on:
mov si,offset led
on: mov al,[si]
cmp al,0ffh
jz re_on

mov   dx, PortA
out   dx, al     ; 输出PortA
inc si
mov bx,1000
Test al,21h
jnz Delay0
mov bx,100
Delay0:
call delay
jmp on
ret
delay :
s:mov cx,1000
loop $
dec bx
cmp bx,0
jnz s
ret
code   ends
end start