8251.asm

使用8251发送数据实验连续发送一个二进制数（比如53H

CODE SEGMENT
ASSUME CS:CODE
DATAPORT1 EQU 50H
CONTRO EQU 51H
CONTPORT EQU 00DFH
DATAPORT EQU 00DEH
DATA1 EQU 0500H
      ORG 1000
START:JMP MAIN
MAIN:CALL FORMAT
     CALL LEDDISP
  L: MOV DX,51H
     IN AL,DX
     AND AL,0H
     JZ L
     MOV DX,50H
     MOV AL,37H
     OUT DX,AL
     JMP L
     MOV AX,4C00H
     INT 21H

LEDDISP: MOV AL,90H
         MOV DX,CONTPORT
         OUT DX,AL
         MOV BYTE PTR DS:[0600H],00
LED1:    CMP BYTE PTR DS:[0600H],07H
         JA LED2
         MOV BL,DS:[0600H]
         MOV BH,0H
         MOV AL,CS:[BX+DATA1]
         MOV DX,DATAPORT
         OUT DX,AL
         ADD BYTE PTR DS:[0600H],01H
         JNZ LED1
LED2:    RET
FORMAT:  MOV BX,0
         MOV WORD PTR DS:[BX+DATA1],3F66H
         ADD BX,2
         MOV WORD PTR DS:[BX+DATA1],4077H
         ADD BX,2
         MOV WORD PTR DS:[BX+DATA1],6D6FH
         ADD BX,2
         MOV WORD PTR DS:[BX+DATA1],7F5BH
         RET
CODE     ENDS 
         END START