SerialUART: Unable to change StopBits to "SerialStopBitCount.Two"

[ArthurOliveiraBR]

Hi folks,

I've tried to modify the "SerialSample" to use two stop bits instead of the default configuration in a RaspberryPI 3 Model B and any value different from "SerialStopBitCount.One" throws an exception as below:

'serialPort.StopBits = SerialStopBitCount.Two' threw an exception of type 'System.ArgumentException' Data: {System.Collections.ListDictionaryInternal} HResult: -2147024809 HelpLink: null InnerException: null Message: "Value does not fall within the expected range." ParamName: null Source: "Windows" StackTrace: " at Windows.Devices.SerialCommunication.SerialDevice.put_StopBits(SerialStopBitCount value)"

My understanding is that it's not allowing any "non-zero' value (SerialStopBitCount.One = 0, SerialStopBitCount.OnePointFive = 1 and SerialStopBitCount.Two = 2).

Anyone else have faced the same issue before?
Can someone try to reproduce it?

Entire function source code as reference:

private async void comPortInput_Click(object sender, RoutedEventArgs e)
        {
            try
            {
               string aqs = SerialDevice.GetDeviceSelector("UART0");                   /* Find the selector string for the serial device   */
                var dis = await DeviceInformation.FindAllAsync(aqs);                    /* Find the serial device with our selector string  */
                serialPort = await SerialDevice.FromIdAsync(dis[0].Id);                  /* Create an serial device with our selected device */

                if (serialPort == null) return;

                // Disable the 'Connect' button 
                comPortInput.IsEnabled = false;

                // Configure serial settings
                serialPort.WriteTimeout = TimeSpan.FromMilliseconds(1000);
                serialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000);
                serialPort.BaudRate = 38400;
                serialPort.Parity = SerialParity.None;
                serialPort.StopBits = SerialStopBitCount.Two;  // THIS LINE THROWS AN EXCEPTION
                serialPort.DataBits = 8;
                serialPort.Handshake = SerialHandshake.None;

                // Display configured settings
                status.Text = "Serial port configured successfully: ";
                status.Text += serialPort.BaudRate + "-";
                status.Text += serialPort.DataBits + "-";
                status.Text += serialPort.Parity.ToString() + "-";
                status.Text += serialPort.StopBits;

                // Set the RcvdText field to invoke the TextChanged callback
                // The callback launches an async Read task to wait for data
                rcvdText.Text = "Waiting for data...";

                // Create cancellation token object to close I/O operations when closing the device
                ReadCancellationTokenSource = new CancellationTokenSource();

                // Enable 'WRITE' button to allow sending data
                sendTextButton.IsEnabled = true;

                Listen();
            }
            catch (Exception ex)
            {
                status.Text = ex.Message;
                comPortInput.IsEnabled = true;
                sendTextButton.IsEnabled = false;
            }
        }

Thanks in advance!

[Apflkuacha]

I also encountered this problem, this is most probably a bug (or unsupported feature) in Windows IoT

Edit: it is possible to set it on external devices (USB - Serial converters)
At the internal serial port it isn't possible to set StopBits.