ad574.asm

汇编相关。D/A转换和A/D转换

AD574_0  EQU  9C00H
AD574_1  EQU  9C01H

DATA SEGMENT
DTABLE DB 31H,30H,56H,49H,4EH,3AH,20H,'$'
HB    DB  ?
LB    DB  ?
DATA ENDS

CODE SEGMENT
	ASSUME CS:CODE,DS:DATA

START:	MOV AX,DATA
	MOV DS,AX
        MOV DX,AD574_0
	OUT DX,AL
	CALL DALLY
        MOV DX,AD574_0
        IN AL,DX
        MOV HB,AL
        CALL DALLY
        MOV DX,AD574_1
        IN AL,DX
        MOV LB,AL
        MOV AL,HB
	AND AL,0F0H
	MOV CL,04H
	SHR AL,CL
	CMP AL,09H
	JG A1
	ADD AL,30H
	JMP A2
A1:	ADD AL,37H
A2:     MOV DX,OFFSET DTABLE  
        PUSH AX
	MOV AH,09H
	INT 21H
        POP AX 
	MOV DL,AL
        MOV AH,02H
	INT 21H
	MOV AL,HB
	AND AL,0FH
	CMP AL,09H
	JG A3
	ADD AL,30H
	JMP A4
A3:	ADD AL,37H
A4:	MOV DL,AL
        MOV AH,02H
	INT 21H

        MOV AL,LB
 	AND AL,0F0H
	MOV CL,04H
	SHR AL,CL
	CMP AL,09H
	JG A5
	ADD AL,30H
	JMP A6
A5:	ADD AL,37H
A6:	MOV DL,AL
        MOV AH,02H
	INT 21H

	CALL DALLY
        MOV DL,0DH
        MOV AH,02H
	INT 21H
        CALL BREAK
  	JMP START

DALLY:	PUSH CX
	PUSH AX
	MOV CX,4000H
A7:     MOV AX,0600H
A8:	DEC AX
	JNZ A8
	LOOP A7
	POP AX
	POP CX
	RET

BREAK  PROC  NEAR 
        MOV AH,06H
        MOV DL,0FFH
        INT 21H
        JE  RETURN
        MOV AX,4C00H
        INT 21H
RETURN:RET
BREAK  ENDP
	
CODE ENDS
     END START