public Form1()
    {
        InitializeComponent();
    }




    private void Form1_Load(object sender, EventArgs e)
    {
        string[] ports = SerialPort.GetPortNames();
        CoMports_list.Items.AddRange(ports);
        CoMports_list.SelectedIndex = 0;
        serialPort1.DataReceived+= new System.IO.Ports.SerialDataReceivedEventHandler(serialPort1_DataReceived);
    }



    private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {
        while ((serialPort1.IsOpen) && (serialPort1.BytesToRead > 0))
        {
            rxString = string.Empty;
            try
            {
                rxString = serialPort1.ReadTo("\r\n");
                this.Invoke(new EventHandler(handleRXData));
                while ((serialPort1.IsOpen)) ;
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception.Message , "can not received data");
               
            }
        }

    
    }



    public void addToLog(string text)
    {
        richTextBox1.AppendText(text + "\r");
        richTextBox1.ScrollToCaret();
    }


    private void handleRXData(object sender, EventArgs e)
    {
        char[] charsToTrin = {'<', '>', '[', ']', ' '};
        int tmp;

        if (rxString.IndexOf("ok") >=0)
        {

                addToLog(string.Format("<{0}",rxString));

            return;

        }
        else if (((tmp = rxString.IndexOf('<')) >= 0) && (rxString.IndexOf('>') > tmp))
        {
            if (scroling_chek_box.Checked)
                addToLog(rxString);
           
            return;
        }

    }



    private void Connect_btn_Click(object sender, EventArgs e)
    {

        serialPort1.BaudRate = Convert.ToInt32(baudRate_list.Text);
        try
        {
            serialPort1.PortName = CoMports_list.Text;
            serialPort1.Open();
        }
        catch (Exception er)
        {
            MessageBox.Show(er.Message, "message", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

    }

    private void timer1_Tick(object sender, EventArgs e)
    {

        if (serialPort1.IsOpen) // 
        {
            try
            {
                var dataArray = new byte[]
                {
                    Convert.ToByte('?')
                }; 
                serialPort1.Write(dataArray, 0, 1);                      
            }
            catch (Exception er)
            {

                serialPort1.Close(); 
            }
        }


    }

}