4a_8255输出.asm

来自「自己做的单片机Proteus仿真实例」· 汇编 代码 · 共 61 行

   ;8255
       org 0000h
       LJMP START
       ORG 0030h

START:     
       mov   a,#80h
       mov   dptr,  #0FFFFH
       movx  @dptr,a
Loop:	mov  7eh,#0C0h
	mov  7dh,#0F9h
	mov  7ch,#0a4h
	mov  7bh,#0B0h
	mov  7ah,#99h
	mov  79h,#92h
l3:	mov  r3,#6	
       	mov  r0,#7eh
	MOV  r2,#01H
l1:	
Output: MOV  DPTR,#7FFFH
	mov  a,r2
	MOVX @DPTR,A

	rl a
	mov   r2,a
	mov   a, @r0
	 
       mov   dptr,#3FFFH
       movx  @dptr, a
	dec   r0
	Acall  Delay1
	;mov  20h,#100
l2:

	
	djnz r3,l1
	sjmp    l3	

      
	POP   ACC
       rl    a
       djnz  r2, Output
       ljmp  Loop

Delay:
       mov   r6, #0
       mov   r7, #0
DelayLoop:
       djnz  r6, DelayLoop
       djnz  r7, DelayLoop
       ret
Delay1:
       mov   r4, #03
loop2: mov   r5, #0ffh
Loop1:
       djnz  r5, Loop1
       djnz  r4, Loop2
       ret
       end