AccessViolation beim öffnen einer Com Verbindung

[EDatabaseError]

Wenn ich mit diesem Code:

Delphi-Quellcode:

procedure TfComm.Button1Click(Sender: TObject);
begin
 GroupBox1.Enabled := false;
 Combobox1.Enabled := false;

 
 rs2321 := trs232.create(self);

 with rs2321 do begin
  ComPortSpeed := br19200;
  ComPortDatabits := db8bits;
  ComPortHwHandshaking := hhNone;
  ComPortParity := ptNone;
  ComPortStopBits := sb1bits;
  ComPortSwHandshaking := shnone;
  TimeOut := -1;
  TimeOutException := false;
 end;

 case combobox1.ItemIndex of
  0: rs2321.ComPort := pnCom1;
  1: rs2321.ComPort := pnCom2;
  2: rs2321.ComPort := pnCom3;
  3: rs2321.ComPort := pnCom4;
 end;

 RS2321.Connect;

 if RS2321.Connected then
  begin
   (Sender as tbutton).Caption := 'Verbindung erfolgreich!';

   GroupBox2.Enabled := false;
   Button1.Enabled := false;
   GroupBox3.Enabled := true;
   Button2.Enabled := true;
  end
 else
  messagedlg('Fehler bei dem Herstellen der Verbindung!'+#13+#10+'Bitte das Kabel nochmals überprüfen.', mtError, [mbOK], 0);
end;

...versuche eine RS232 Verbindung herstellen knallts in der Zeile : RS2321.Connect;

Die Connect Funktion sieht folgendermaßen aus:

Delphi-Quellcode:

function TCommPortDriver.Connect: boolean;
var comName: array[0..4] of char;
    tms: TCOMMTIMEOUTS;
begin
  FDatainbuffer('A');
  // Do nothing if already connected
  Result := Connected;
  if Result then exit;
  // Open the COM port
  StrPCopy( comName, 'COM' );
  comName[3] := chr( ord('1') + ord(FComPort) );
  comName[4] := #0;
  FComPortHandle := CreateFile(
                                comName,
                                GENERIC_READ or GENERIC_WRITE,
                                0, // Not shared
                                nil, // No security attributes
                                OPEN_EXISTING,
                                FILE_ATTRIBUTE_NORMAL,
                                0 // No template
                              ) ;
  Result := Connected;
  if not Result then exit;
  // Apply settings
  ApplyCOMSettings;
  // Setup timeouts: we disable timeouts because we are polling the com port!
  tms.ReadIntervalTimeout := 1; // Specifies the maximum time, in milliseconds,
                                // allowed to elapse between the arrival of two
                                // characters on the communications line
  tms.ReadTotalTimeoutMultiplier := 0; // Specifies the multiplier, in
                                       // milliseconds, used to calculate
                                       // the total time-out period
                                       // for read operations.
  tms.ReadTotalTimeoutConstant := 1; // Specifies the constant, in milliseconds,
                                     // used to calculate the total time-out
                                     // period for read operations.
  tms.WriteTotalTimeoutMultiplier := 0; // Specifies the multiplier, in
                                        // milliseconds, used to calculate
                                        // the total time-out period
                                        // for write operations.
  tms.WriteTotalTimeoutConstant := 0; // Specifies the constant, in
                                      // milliseconds, used to calculate
                                      // the total time-out period
                                      // for write operations.
  SetCommTimeOuts( FComPortHandle, tms );

  Sleep(1000);  // to avoid timing problems, wait until the Comm-Port is opened
end;

(Für die die es wissen wollen die Exception tritt genau bei pop esi auf)

In einer anderen Anwendung funktioniert alles...ohne Exception.


Hoffe ihr könnt mir helfen.



Mfg
Tobi