9tx.asm

几个接口实验的代码。内含：8253、8255、8237、8251、DA0832、AD0809等芯片的实验代码！

code segment
   assume cs:code,ds:code
start:
    mov ax,code
    mov ds,ax
   
s1: 
    mov cx,1ffh  ;锯齿波
   
    mov al,0ffh
s4: mov dx,228h
    out dx,al
    mov dx,229h
    out dx,al
    inc al
    loop s4
l5: dec al     ;输出高低平
    mov dx,228h
    out dx,al
    mov dx,229h
    out dx,al
    loop l5


    jmp s1

code     ends
   end     start