请教高手、前辈们51 单片机串口通讯问题

只看该作者 · 2007-12-13 23:24

pc机我采用串口助手，单片机at89c2051。目的，从pc机传命令“aa2425”(字符串)给单片机，单片机接收到数据后正确，上传50h(16进制)，错误上传05h。
但是结果传送“aa4aaa"（61h61h34h61h61h61h ---16进制传）是正确的，程序如下，请高手指点一二。
           ORG     0000h
           AJMP    MAIN
           ORG     0023H
           AJMP    SERVUART
           org     0030h
MAIN:      MOV PSW,#00H      ;0区  默认
;;;;;;;;;;;;;;设置T1;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
           mov TMOD,#20H     ;T1方式2
           MOV TH1,#0FDH     ;12MHZ,BOTERATE 9600,加倍192000
           MOV TL1,#0FDH     ;自动加载值
           SETB TR1          ;启动定时器1 ,注意顺序

           MOV SCON,#50H     ;串口工作方式1，允许接收数据
           MOV PCON,#00H     ;SMOD=0不加倍

           SETB EA           ;开中断
           SETB ES           ;允许串口中断
           MOV R1,#06H       ;接收字节个数

HERE:      SJMP HERE

           ORG  0060H
SERVUART:  CLR EA
           PUSH PSW
           JBC RI,LOOP1
           JBC TI,ENDT

LOOP1:     mov A,R1
           XRL A,#06H
           JZ  RECEIVE1

           XRL A,#05H
           JZ  RECEIVE2

           XRL A,#04H
           JZ  RECEIVE3

           XRL A,#03H
           JZ  RECEIVE4

           XRL A,#02H
           JZ  RECEIVE5

           XRL A,#01H
           JZ  RECEIVE6
RECEIVE1:  MOV A,SBUF
           CJNE A,#61H,ERROR
           SJMP  NEXT
RECEIVE2:  MOV A,SBUF
           CJNE A,#61H,ERROR
           SJMP  NEXT
RECEIVE3:  MOV A,SBUF
           CJNE A,#32H,ERROR
           SJMP  NEXT
RECEIVE4:  MOV A,SBUF
           CJNE A,#34H,ERROR
           SJMP  NEXT
RECEIVE5:  MOV A,SBUF
           CJNE A,#32H,ERROR
           SJMP  NEXT
RECEIVE6:  MOV A,SBUF
           CJNE A,#35H,ERROR
           SJMP  NEXT

ERROR:     MOV A,#05H       ;错误应答信号
           MOV SBUF,A
WAIT1:     JBC TI,ENDT
           SJMP WAIT1

NEXT:      DEC R1             ;不正确r1不减一，直到下一个数据对
           CJNE R1,#00H,ENDT
           CLR P3.7
           MOV A,#50H        ;正确应答信号
           MOV SBUF,A
WAIT2:     JBC TI,ENDT
           SJMP WAIT2

ENDT:      POP PSW
           SETB EA
           RETI
           END