程序代码：

    .MODEL    TINY
;PC.0-----------------CS----------KZ7
;PC.1-----------------I/O CLK-----KZ5
;PA.0-----------------DO----------KZ4
;
Con_8255    EQU    0F003H
PC_8255        EQU    0F002H
PA_8255         EQU     0F000H 
EXTRN    Display8:NEAR

    .STACK        300 
    .DATA
buffer        DB    8 DUP(0)                ;数据临时存放区

    .CODE        
START:        MOV    AX,@DATA
            MOV    DS,AX
            MOV    ES,AX
            NOP
            CALL    Init8255
            
MAIN:            CALL    Read549                ;从TLC549读取两次AD转换结果
            CALL    DL2
            CALL    Read549
            CALL    DIS_BCD
            CALL    DelayTime
        ;提取电压数据，转换为非压缩型BCD码,并显示
            JMP    MAIN

;********************************
;电压电流转换/显示
;********************************       
DIS_BCD        PROC    NEAR
            MOV    AX,BX
            LEA    DI,buffer+7
            STD
            MOV    AL,10H                    ;10H表示不需要显示
            STOSB                       ;STD地址减，buffer+7654不显示
            STOSB
            STOSB
            STOSB
            STOSB
                
                    XOR    AH,AH
            MOV    BL,51                    ;255/51 (16进制的1 = 1/51V)
            DIV    BL
            OR    AL,80H                    ;加上小数点
            MOV    BUFFER+2,AL
        
            MOV    AL,10
            MUL    AH
            DIV    BL
            MOV    BUFFER+1,AL                ;第一位小数
        
            MOV    AL,10
            MUL    AH
            DIV    BL
            MOV    BUFFER,AL                ;第二位小数
        
            LEA    SI,buffer                ;显示    
            CALL    Display8
            RET
DIS_BCD        ENDP

;延时程序
DelayTime    PROC    NEAR
            XOR    CX,CX
            ;LOOP    $
            ;loop   $
            ;loop   $
            RET
DelayTime    ENDP        

DL1        PROC    NEAR
        PUSH    CX
        ;MOV    CX,2000
;DL11:        LOOP    DL11
        POP    CX
        RET
DL1        ENDP

DL2        PROC    NEAR
        PUSH    CX
        ;mov    CX,20000
        ;loop    $
        POP    CX
        nop
        nop
        RET
DL2        ENDP

;读操作
Read549      PROC    NEAR
        PUSH    CX
        MOV     CX,8                ;数据一共有8位
         MOV    DX,PC_8255            ;CS=1,CS=0 
               MOV     AL,0FFH
               OUT     DX,AL
               mov     dx,Con_8255
               mov     al,02H
               out     dx,al
               nop
               nop
               nop
               nop
               mov     AL,00H
               OUT     DX,AL
               nop
               nop
               nop
               nop
           
Read549_1:      MOV     DX,PA_8255
               IN      AL,DX
               ROR     AL,1
        RCL     BL,1
               MOV     DX,Con_8255
               ;MOV     AL,00H              ;CLK高，CS低，TLC549在外部CLK下降沿输出数据
               ;OUT     DX,AL
               mov     AL,03H
               out     dx,al
               call    DL1
               MOV     AL,02H              ;CLK低，CS低
               OUT     DX,AL
            LOOP    Read549_1
            
            MOV     AL,03H
            MOV     DX,Con_8255
               out     DX,AL
               mov     al,01H
               out     dx,al
               POP     CX
               RET
Read549     ENDP        


Init8255    PROC    NEAR
            MOV    DX,Con_8255
            MOV    AL,90H
            OUT    DX,AL
            RET
Init8255    ENDP

            END    START