;gg203.asm/gg3.asm
;for 讀A口送B口<芯片8255A：A口接4開關,B口接1個八段顯示器，pc7單脈沖>
;2005-05
;lcy/p_Sa
data	SEGMENT
        BUF	DB	0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H,88h,83h,0c6h,0a1h,86h,09h;0-F八段顯示器代碼
        PA	EQU	280h
        PB	EQU	281h
        PC	EQU	282h
        PCTL EQU	283h
data	ENDS
stack0 SEGMENT para stack
        DW	20h	DUP(0)
stack0 ENDS
        
coseg	SEGMENT
        ASSUME CS:coseg,DS:data,SS:stack0
start:  MOV AX, data
        MOV DS, AX
;================MOV-DS-AX============== 
        MOV DX, PCTL
        MOV AL, 98h	;1-0011-000B:A口方式0輸入，B口方式0輸出
        OUT DX, AL
        XOR BX, BX
        LEA BX, BUF
        MOV CX, 30H

    L1: MOV DX, PC
        IN  AL, DX
        TEST AL, 80H
        JZ	L1
        MOV DX, PA
        IN AL, DX
        AND AL, 0FH	;A口輸入取低4位
        XLAT		;AL <= ((BX)+(AL))，AL取得相應八段顯示器代碼
        			;或者
        			;XOR BX, BX
        			;MOV BL, AL
        			;MOV AL, BYTE PTR BUF[BX]
        INC DX		;A口變B口
        OUT DX, AL
        MOV DX, PC
    L2: IN  AL, DX
        TEST AL, 80H
        JNZ	L2
        LOOP	L1 
;================INT-21H================
        MOV AH, 4ch
        INT 21h
coseg	ENDS
        END	start