How to write the raw data coming from a serial port to a .txt file

Question

I am currently working on a project with a STM32 that reads from a camera and sends the data through an UART connection.

On the other end I have my C# application connected to the serial port where the data is coming. I write incoming data in a.txt file to see what it looks like for now, before going further in my project (putting back the data into an image in C#).

This is the function that writes in the.txt upon the "receive" button being pressed.

private void btnReceive_Click(object sender, EventArgs e)
{
    try
    {
        if (serialPort1.IsOpen)
        {
            //Debug.Write(serialPort1.ReadExisting());
            using (StreamWriter writetext = new StreamWriter("write.txt", false, Encoding.UTF8))
            {
                writetext.WriteLine(serialPort1.ReadExisting());
            }
        }

    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

Here I get the data with a UTF8 encoding, but my wish would be to be able to write the data in a raw way, with no encoding at all. But I have no idea how to write the decimal value coming in the serial port directly in the file. Is there something else than the StreamWriter that I can use? Or another king of encoding value?

NB: using Docklight I am able to get some positive results regarding the data I receive, but I can't get the same in my own app.

Answer 1

If you just want to read bytes from the port and write these to a file, you need to read bytes from the port.

var buffer = new byte[serialPort1.ReadBufferSize];
using var fs = File.OpenWrite(...);
while(serialPort1.IsOpen){
    var readBytes = serialPort1.Read(buffer, 0, buffer.Length);
    fs.Write(buffer, 0, readBytes );
}

Note that if the data is actually text it will still use some form of encoding, it will just use whatever encoding the sending device is using.