C# serial port issues

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Hi everyone.

Iam having some trouble reading data from my serial port.
Iam sending data from two sensors every second as a ;-seperated string and want to read them and update two textboxes continously.

When I try to read data from the Serial port with ReadExcisting() Iam getting more then just the two values. Readline() doesn't seem to work either.

Any help woule be great:-)

Thanks in advance,

Michael

What I have tried:

C#

private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort sp = (SerialPort)sender;
    string inData = sp.ReadExisting();
    data = inData.Split(delimiterChars);

    if(data.Contains("Temp1"))
    {
        Temp1txt.Invoke(this.myDelegate, new Object[] { data });
    }
    else if (data.Contains("Temp2"))
    {
        Temp2txt.Invoke(this.myDelegate, new Object[] { data });
    }

    richBox1.Invoke(new Action(() => { richBox1.AppendText(data[1]); }));
    richBox1.Invoke(new Action(() => { richBox1.SelectionStart = richBox1.Text.Length; }));            
    richBox1.Invoke(new Action(() => { richBox1.ScrollToCaret(); }));
}

Posted 9-Jan-17 23:46pm

MikeSv_

Updated 10-Jan-17 3:40am

#realJSOP

v2

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#realJSOP 10-Jan-17 6:05am

What is the additional data you're getting that you're not expecting?

2 solutions

Solution 2

Thanks!

I just send a new line character from Microcontroller which works perfectly!

Best regards,

Michael

Posted 10-Jan-17 3:40am

MikeSv_

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Jochen Arndt · Accepted Answer · 2017-01-10T00:05:00

ReadExisting reads all data available in the internal input buffer. This might be multiple data sets if the previous read was too long ago and might also be an incomplete last data set.

So you need some kind of detection to differentiate between data sets and if the last data are complete. This depends on the format of your data. Often a data set is terminated by a line feed which can then be used. If so, ReadLine can be used instead (and should be used because it makes processing the data much simpler).

But when ReadLine does not return, there seems to be no or a different end of line indicator. If there is a different indicator, you can set it using the SerialPort.NewLine Property (System.IO.Ports)[^] to let ReadLine return when that character is received.

So it depends on the end of line / data set indicator that is used by your sensors.