private void BtnDisconnect_Click(object sender, EventArgs e)
        {
            try
            {
                if (UART.IsOpen)
                {
                    while (UART.BytesToWrite > 0)
                    {
                    }
                    UART.DiscardInBuffer();
                    UART.Dispose();
                    UART.Close();

                    btnConnect.Enabled    = true;
                    btnDisconnect.Enabled = false;
                    lblStatus.Text        = "Port is closed !";
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
 private void BtnConnect_Click(object sender, EventArgs e)
 {
     try
     {
         if (UART.IsOpen == true)
         {
             UART.DiscardInBuffer();
             UART.Close();
         }
         UART.PortName = cbxCom.Text;
         UART.Open();
         lblStatus.Text = "PC is connecting with " + UART.PortName.ToString();
         if (UART.IsOpen == true)
         {
             btnConnect.Enabled    = false;
             btnDisconnect.Enabled = true;
             btnStart.Enabled      = true;
         }
     }
     catch
     {
         MessageBox.Show("Bạn chưa chọn cổng COM !");
     }
 }