adzhuanhuan.txt

D/A转换程序

Z8279    EQU       212H
D8279    EQU       210H
LEDMOD   EQU       00   ;左边输入,八位显示外部译码八位显示
LEDFEQ   EQU       38H ;扫描频率
CODE     SEGMENT
ASSUME    CS:CODE,DS:code
START:   push      cs
	        pop       ds
	        call       delay
	        MOV     DX,Z8279
	        MOV     AL,LEDMOD
	        OUT      DX,AL
	        MOV     AL,LEDFEQ
	        OUT      DX,AL
		     MOV     CX,06H
XZ:       MOV     DX,D8279
	         MOV     AL,00H
	         OUT     DX,AL
	         LOOP     XZ
	         MOV     DX,D8279  
	        MOV     AL,5eH
	        OUT      DX,AL        
	        MOV     DX,D8279
	        MOV     AL,77H
	        OUT      DX,AL           ;以上为写(AD     )
	        NOP
  bg:    mov   dx,208h
	       mov   al,0
	    out   dx,al
	    call   delay
	    in    al,dx
		 mov   cl,04h
	     ror   al,cl
	     and   al,0fh
	     MOV   BL,AL             ;查表,将键码放入AL中
	  push    ax
       mov    cx,08h
       mov    al,00h
 clear:  out    dx,al
      loop  clear
	     mov    dx,z8279
	     mov    al,83h
	     out    dx,al
MOV    AL,BL
	     pop    ax
	     LEA    BX,LED
	     XLAT
	     MOV    DX,D8279          ;将AL中内容写到数码管上
	     OUT    DX,AL
	     call   delay
	     jmp bg
LED  DB  3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH,77H,7CH,39H
      DB  5EH,79H,71H
delay proc near
push cx
	mov cx,0f00h
	loop $
	pop cx
	ret
delay endp
CODE  ENDS
END   START