private void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
                try
                {
                    m_buffer = serialPort.ReadExisting();

                    if (m_buffer.Length >=2 && m_buffer.Substring(m_buffer.Length - 2, 2) == "\r\n")
                    {
                        this.Invoke((Action)delegate
                        {
                            this.txtSerialText.Text += m_buffer;
                        });

                        m_buffer = string.Empty;
                    }
                    if (!(serialPort.IsOpen))
                        serialPort.Open();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "");
                }
        }