8255流水燈顯示代碼

; You may customize this and other start-up templates;

; The location of this template is c:\emu8086\inc\0_com_template.txt

org 100h

;T8255-2.asm

;8255流水燈顯示實驗

;****************根據(jù)查看端口資源修改下列符號值*******************

IOY0 EQU 00H ;片選IOY0對應(yīng)的端口始地址

;*****************************************************************

MY8255_A EQU IOY0+00H*2 ;8255的A口地址

MY8255_B EQU IOY0+01H*2 ;8255的B口地址

MY8255_C EQU IOY0+02H*2 ;8255的C口地址

MY8255_MODE EQU IOY0+03H*2 ;8255的控制寄存器地址

DATA SEGMENT

LA DB 1 DUP

LB DB 1 DUP

AXX DW 1 BUP

CXX DW 1 BUP

DATA ENDS

CODE SEGMENT

ASSUME CS:CODE,DS:DATA

START: MOV AX,DATA

MOV DS,AX

MOV DX,MY8255_MODE ;定義8255工作方式

MOV AL,80H ;工作方式0，A口和B口為輸出

OUT DX,AL

BEGIN: MOV DX,MY8255_A ;寫A口發(fā)出的起始數(shù)據(jù)

MOV AL,01H

OUT DX,AL

MOV LA,AL

MOV DX,MY8255_B ;寫B(tài)口發(fā)出的起始數(shù)據(jù)

MOV AL,80H

OUT DX,AL

MOV LB,AL

MOV CX,7

LOOP1: CALL DALLY

MOV AL,LA ;將A口起始數(shù)據(jù)左移再寫入A口

ROL AL,1

MOV LA,AL

MOV DX,MY8255_A

OUT DX,AL

MOV AL,LB ;將B口起始數(shù)據(jù)右移再寫入B口

ROR AL,1

MOV LB,AL

MOV DX,MY8255_B

OUT DX,AL

LOOP LOOP1

MOV CX,7

LOOP2: CALL DALLY

MOV AL,LA ;將A口起始數(shù)據(jù)右移再寫入A口

ROR AL,1

MOV LA,AL

MOV DX,MY8255_A

OUT DX,AL

MOV AL,LB ;將B口起始數(shù)據(jù)左移再寫入B口

ROL AL,1

MOV LB,AL

MOV DX,MY8255_B

OUT DX,AL

LOOP LOOP2

JMP BEGIN ;流水燈重新開始

DALLY PROC ;軟件延時子程序

MOV CXX,CX

MOV AXX,AX ;這里本應(yīng)該用堆棧，我用CXX，AXX變量代替了。

MOV CX,0FH

D1: MOV AX,0FFFH

D2: DEC AX

JNZ D2

LOOP D1

MOV AX,AXX

MOV CX,CXX

RET

DALLY ENDP

CODE ENDS

END START

ret

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