CODEWITHSUNDEEP
c#serial-port
K Sco
K Sco

Reputation: 51

SerialPort Write does not trigger any BytesToRead in the buffer

I'm writing a sequence to a serial port telling it to send me data. After sending the sequence and trying to read the data from the serial port there is nothing there. However, if I close the program and open the port in HyperTerminal, the data immediately shows up without needed to prompt for it.

private string ReadSerialPort()
    {
       var _comPort = new SerialPort()
       {
            PortName = "COM2",
            BaudRate = 1200,
            DataBits = 7,
            Parity = System.IO.Ports.Parity.Odd,
            StopBits = System.IO.Ports.StopBits.One,
            NewLine = Environment.NewLine,
            WriteTimeout = 500,
            ReadTimeout = 500,
            Handshake = System.IO.Ports.Handshake.None
        };

        if (!_comPort.IsOpen)
        {
            _comPort.Open();
        }

        int unicode = 27;
        char character = (char)unicode;
        string text = character + "P";

        _comPort.WriteLine(text);

        //System.Threading.Thread.Sleep(200); // Didn't help

        string serialData = string.Empty;
        while (serialData.Length == 0)
        {
            serialData = _comPort.ReadLine();
        }

        return serialData;
    }

If I write the escape sequence to the serial port 3 times, I will see nothing in my code but if I open up HyperTerminal it will appear 3 times.

What could be causing the code to not see anything in the buffer, but I can see it once I exit the program?

Upvotes: 0

Views: 979

Answers (1)

K Sco
K Sco

Reputation: 51

My solution was to set DtrEnable = true. Everything is now working as intended!
This question helped lead me to the solution

SerialPort.DtrEnable Property

Upvotes: 2

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