大家好！不知道是什么原因？ (100分)

我用delphi编的串口通讯程序接收插在PCI插槽板上的数据出错。
我板上发送的数据是55H，而接收的是‘fffef8’而且每次接收的都不一样。请问是什么原因？
我用本机的com2口接收。
delphi程序如下：
unit Comm;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, SPComm;

type
TFCOMM = class(TForm)
Memo1: TMemo;
Btn_send: TButton;
Button1: TButton;
Comm2: TComm;
Memo2: TMemo;
procedure FormShow(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure Btn_sendClick(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Comm2ReceiveData(Sender: TObject; Buffer: Pointer;
BufferLength: Word);
private
{ Private declarations }
public
{ Public declarations }
end;

var
FCOMM: TFCOMM;
Viewstring:string;
i:integer;
rbuf,sbuf:array[1..5] of byte; //定义发送和接收数组

implementation

{$R *.DFM}

procedure TFCOMM.FormShow(Sender: TObject);
begin
//comm1.StartComm; //打开串口
comm2.StartComm;
end;

procedure TFCOMM.FormClose(Sender: TObject; var Action: TCloseAction);
begin
// comm1.StopComm; //关闭串口
comm2.StopComm;
end;

procedure senddata; //自定义的发送数据过程
var
i:integer;
commflg:boolean;
begin
viewstring:='';
commflg:=true;
for i:=1 to length(sbuf) do
begin
if not fcomm.comm2.writecommdata(@sbuf,1) then
begin
commflg:=false;
break;
end;
sleep(2); //发送时字节间的延时
viewstring:=viewstring+inttohex(sbuf,2)+'';
end;
viewstring:='发送:'+viewstring;
fcomm.memo1.lines.add(viewstring);
//fcomm.memo1.lines.add('');
if not commflg then
messagedlg('发送失败!',mterror,[mbyes],0);
end;

procedure TFCOMM.Btn_sendClick(Sender: TObject);
begin
sbuf[1]:=byte($55);
sbuf[2]:=byte($00);
sbuf[3]:=byte($00);
sbuf[4]:=byte($00);
sbuf[5]:=byte($55);
senddata;{调用发送函数}
end;

procedure TFCOMM.Button1Click(Sender: TObject);
begin
close();
end;

procedure TFCOMM.Comm2ReceiveData(Sender: TObject; Buffer: Pointer;
BufferLength: Word); //COM2接收过程
var
i:integer;
begin
viewstring:='';
move(buffer^,pchar(@rbuf)^,bufferlength);
for i:=1 to BufferLength do
begin
viewstring:=viewstring+inttohex(rbuf,2)+'';
end;
viewstring:='接收:'+viewstring;
memo2.lines.add(viewstring);
//memo2.lines.add('');
end;

end.

如果我没有说清楚，请给我指出来，谢谢！

波特率不一致