VaComm.Close() Program Freezes

VCL TMS Async
1

Good day,
I have been using the VaComm component for many years, everything is always ok.
Currently I have a problem with one device where the COM port is virtual from USB.
I created a separate simple application (Delphi 7), VaComm1, Button1 - Connect, Button2 - Disconnect.
The VaComm1.Close () command blocks the entire application, it cannot be terminated via the task manager.

  • I usually use USB <-> RS232 (maybe only another manufacturer)
  • I do not send or indirect anything after opening the port
  • other devices, other ports do not behave this way
  • created a similar application in Visual Studio 2019. I will open the COM port, write the text, close it - everything is OK.
  • using foreign applications (Hercules SETUP utility | HW-group.com) - https://www.hw-group.com/files/styles/large/public/swapplication/5462- hercules-setup-utility / anothersterminal19b.png? itok = bVr8wN0l
  • I also tried VaComm1.PurgeReadWrite before closing
  • Read and write buffers are empty
  • I purchased and updated to the latest version. Same behavior.
  • when opening the data sending port it works, I just deleted it all. I am not able to close the port with or without communication.

thanks for support

Zdenek

2

Not sure what is causing this.
Are you executing any other code after calling .Close()? What is "Disconnect" ? Does this mean you physically disconnect the USB?

3

Thank you for your response.
procedure TForm1.Button1Click (Sender: TObject);
begin
VaComm1.Open;
end;

procedure TForm1.Button2Click (Sender: TObject);
begin
VaComm1.Close;
end;

Nothing else. I start the application, click on Button1 and then on Button2. The application is frozen and cannot be terminated.

Further information:

  • disconnect here I mean .Close (). I'm not dealing with anomalies with USB disconnection ...
  • it is a POS device and the virtual COM port (in this case COM8) is a printer.
  • the printer transmits CTS, DSR status
  • on the same device another (non-virtual) COM (1,2,3). Open () /. Close () is ok. No device is connected to COM1,2,3.
  • The device is also available via TeamViewer if there is interest
  • I found (my) very old application with VaComm component, which has no problem with .Open () /. Close ().
    I will now translate this application with VaComm version 2.0.2.0 or 2.2.0.1 and the application will start freezing.
    The old * .dfm does not contain an info version of the component, so I don't know when this behavior started.
    Old * .dfm
    object VaComm1: TVaComm
    Baudrate = br19200
    FlowControl.OutCtsFlow = False
    FlowControl.OutDsrFlow = False
    FlowControl.ControlDtr = dtrDisabled
    FlowControl.ControlRts = rtsEnabled
    FlowControl.XonXoffOut = False
    FlowControl.XonXoffIn = False
    FlowControl.DsrSensitivity = False
    FlowControl.TxContinueOnXoff = False
    DeviceName = '\. \ COM% d'
    MonitorEvents = [ceCts, ceError, ceRxChar, ceTxEmpty]
    Buffers.WriteSize = 12072
    OnCts = VaComm1Cts
    OnRxChar = VaComm1RxChar
    Left = 208
    Top = 16
    end

New * .dfm
object VaComm1: TVaComm
Baudrate = br19200
FlowControl.OutCtsFlow = False
FlowControl.OutDsrFlow = False
FlowControl.ControlDtr = dtrDisabled
FlowControl.ControlRts = rtsEnabled
FlowControl.XonXoffOut = False
FlowControl.XonXoffIn = False
FlowControl.DsrSensitivity = False
FlowControl.TxContinueOnXoff = False
DeviceName = '\. \ COM% d'
MonitorEvents = [ceCts, ceError, ceRxChar, ceTxEmpty]
Buffers.WriteSize = 12072
SettingsStore.RegRoot = rrCURRENTUSER
SettingsStore.Location = slINIFile
OnCts = VaComm1Cts
OnRxChar = VaComm1RxChar
Version = '2.2.0.1'
Left = 208
Top = 16
end

Have a nice day
Zdenek

1 Like
4

I could not reproduce this. Test project attached.
Project1.zip (4.8 KB)