110.asm

来自「微机原理——接口应用编程源码」· 汇编 代码 · 共 54 行

STACK segment  stack
      dw 64 dup(?)
STACK ends

data segment

data ends

code segment
    assume  cs:code, ds:data
start:
   mov ax,data
   mov ds,ax

   mov dx,43h  ;8253 Init
   mov al,0b6h
   out dx,al

   mov dx,63h  ;8255  Init
   mov al,82h
   out dx,al
 s:mov dx,61h
   in  al,dx
   mov dx,60h
   out dx,al
   cmp al,00b
   jz  A
   cmp al,01b
   jz  B 
   cmp al,10b
   jz  C
   jmp s 

 A: mov ax,2d69h   ;Counternumber(100hz)
    mov dx,42h
    out dx,al
    mov al,ah
    out dx,al
    jmp s
 B: mov ax,048ah    ;(1000hz)
    mov dx,42h
    out dx,al
    mov al,ah
    out dx,al
    jmp s
 C: mov ax,0074h  ;(10khz)
    mov dx,42h
    out dx,al
    mov al,ah
    out dx,al
    jmp s
 
 code ends
 end start