4-d79.asm

编写程序

Z8279    EQU       212H
D8279    EQU       210H

DATA SEGMENT

DATA ENDS

STACK SEGMENT STACK
STA DW 32 DUP(?)
TOP DW ?
STACK ENDS

CODE     SEGMENT
ASSUME  CS:CODE,DS:CODE,SS:STACK
START:  PUSH   CS                     ;初始化
	 	POP    DS
 
	 	MOV       DX,Z8279   ;左边输入,八位显示外部译码八位显示
	        MOV       AL,00H
	        OUT       DX,AL
                		;清FIFO RAM
	 	MOV AL,0C2H
	 	OUT DX,AL
	 
	    MOV CX,8				;LED显示'-'.
   		MOV DX,D8279
	   	MOV AL,40H
LDP:	OUT DX,AL
    	LOOP LDP

WAIIT:  MOV DX,Z8279		   ;检测是否有键按下
TST:	IN     AL,DX
        AND    AL,0FH
	 	CMP    AL,00H
	 	JE     TST             ;AL=0,无键按下则等待; AL<>0,有键按下

		MOV AL,40H				;设置读FIFO RAM命令
		OUT DX,AL

	 	MOV    DX,D8279             ;读入FIFO RAM内容
     	        IN     AL,DX
	 	PUSH 	AX
	 	
	 	MOV    DX,D8279               
     	        LEA    BX,LED 			  ;查表,将键值字形码放入AL中
	 	XLAT
	 	OUT    DX,AL			  ;将AL中内容写到数码管上
	 
	 	POP 	AX	 
	 	CMP    AL,15           ;是结束符(F键)则结束  
	 	JE     FINI
	 
	 	JMP    WAIIT             ;等待下一次键输入
	 
FINI:   MOV DX,Z8279		  
        MOV AL,0D1H           ;清除显示RAM
        OUT DX,AL
FINI1:  IN  AL,DX                
        AND  AL,80H
     
        JNZ  FINI1            ;未清除完等待,或用延时完成(MOV  CX,0FFH   
                              ;                     DELAY : LOOP  DELAY)        
                                                 
        MOV AL,90H               ;置显示RAM地址为0,写入数据后地址自动加1      
        OUT DX,AL
        
        MOV DX,D8279		  ;显示"     End"
        MOV AL,5EH
        OUT DX,AL
        MOV AL,54H
        OUT DX,AL
        MOV AL,79H
        OUT DX,AL
        MOV CX,5      ;填充5个空
        MOV AL,0
WZ:     OUT DX,AL
        LOOP WZ
        
		JMP  $				  ;结束后再按键，则有蜂鸣器声响

	 LED  	DB  3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH,77H,7CH,39H,5EH,79H,71H;0-9,A-F
	        DB  80H,04H,40H,46H,48H,50H,00H,00H; . , - + : 
	 
	 CODE  ENDS
END      START