c# serial port data parsing RRS feed

  • Question

  • Hi,

    I'm a total newbie to VC#, but have managed to scrape a basic terminal program together which reads the data a microcontroller is spewing out (async) using example code and tutorials :P. I'm a little stuck now, as I need to parse the data I am recieving via the serial port.

    Example of data I am recieving:

    Which is displayed in my terminal window as:

    (fyi, the 0 and 1s represent the on/off state of switches connected to the microcontroller, the M and L just indicate the beginning and end of the data set (for ease of reading :P))

    I would like to automatically update a string with the content of each complete line as it is recieved, so I can check and manipulate it, however I have no idea how to create a string such as this, or how to 'stop adding' characters when it reaches the end of each data segment...

    Obviously the program just sees a string of junk and displays it, and I don't know how to put into something more coherent xD

    Here's the code of my program.

    using System; 
    using System.Diagnostics; 
    using System.Collections.Generic; 
    using System.ComponentModel; 
    using System.Data; 
    using System.Drawing; 
    using System.Text; 
    using System.Windows.Forms; 
    using System.IO; 
    using System.IO.Ports; 
    namespace PSComm 
        public partial class Form1 : Form 
            string RxString; 
            public Form1() 
                string[] ports = SerialPort.GetPortNames();//gets the names of COM ports installed in the system and adds them to the port selection list 
                foreach (string port in ports) 
                portBox.DropDownStyle = ComboBoxStyle.DropDownList;//ensures user can't enter their own value 
                portBox.SelectedIndex = 0;//selects the first port in the port selection list 
                baudrateBox.Items.AddRange(new string[] { "2400""9600""19200""38400" });//adds a list of baud rates to the baud rate selection list 
                baudrateBox.DropDownStyle = ComboBoxStyle.DropDownList;//ensures user can't enter their own value 
                baudrateBox.SelectedIndex = 1;//selects 9600bps baud rate 
            private void buttonStart_Click(object sender, EventArgs e) 
                try//attempts to set up and open the selected port 
                    serialPort1.PortName = Convert.ToString(portBox.SelectedItem); 
                    serialPort1.BaudRate = Convert.ToInt32(baudrateBox.SelectedItem); 
                    serialPort1.Handshake = Handshake.None; 
                    serialPort1.Parity = Parity.None; 
                    serialPort1.DataBits = 8; 
                    serialPort1.StopBits = StopBits.One; 
                    if (serialPort1.IsOpen)//temporarily disables the options if the port is successfully opened 
                        buttonStart.Enabled = false
                        buttonStop.Enabled = true
                        terminalBox.ReadOnly = false
                        portBox.Enabled = false
                        baudrateBox.Enabled = false
                catch (Exception ex)//any errors during this operation are captured and displayed in a message box 
            private void buttonStop_Click(object sender, EventArgs e) 
                if (serialPort1.IsOpen)//closes the serial port if it is open 
                buttonStart.Enabled = true;//re-enables the options 
                buttonStop.Enabled = false
                terminalBox.ReadOnly = true
                portBox.Enabled = true
                baudrateBox.Enabled = true
            private void Form1_FormClosing(object sender, FormClosingEventArgs e) 
                if (serialPort1.IsOpen)//closes the serial port if application is exited while it is open 
            private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
                if (!serialPort1.IsOpen) return;//if the port is closed, don't try to send a character 
                char[] buff = new char[1];//if the port is Open, declare a char[] array with one element 
                buff[0] = e.KeyChar;//load element 0 with the key character 
                serialPort1.Write(buff, 0, 1);//send the one character buffer 
                e.Handled = true;//set the KeyPress event as handled so the character won't display locally 
            private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) 
                RxString = serialPort1.ReadExisting();//reads the data in the serial port buffer and stores it in RxString 
                this.Invoke(new EventHandler(DisplayText)); 
            private void DisplayText(object sender, EventArgs e) 
                terminalBox.AppendText(RxString);//updates the terminal box with the value of RxString 

    Any advice is appreciated!

    • Moved by jack 321 Tuesday, September 2, 2008 8:11 AM off topic (Moved from Visual C# General to Off-Topic Posts (Do Not Post Here))
    Thursday, August 28, 2008 6:39 PM

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