FTD2XX_NET.FTDI.Close C# (CSharp) Method

        public FT_STATUS Close()
        {
            // Initialise ftStatus to something other than FT_OK
            FT_STATUS ftStatus = FT_STATUS.FT_OTHER_ERROR;

            // If the DLL hasn't been loaded, just return here
            if (hFTD2XXDLL == IntPtr.Zero)
                return ftStatus;

            // Check for our required function pointers being set up
            if (pFT_Close != IntPtr.Zero)
            {
                tFT_Close FT_Close = (tFT_Close)Marshal.GetDelegateForFunctionPointer(pFT_Close, typeof(tFT_Close));

                // Call FT_Close
                ftStatus = FT_Close(ftHandle);

                if (ftStatus == FT_STATUS.FT_OK)
                {
                    ftHandle = IntPtr.Zero;
                }
            }
            else
            {
                if (pFT_Close == IntPtr.Zero)
                {
                    LogB.Debug("FTD2XX: Failed to load function FT_Close.");
                }
            }
            return ftStatus;
        }

		private void AttemptConnect()
		{
			connected = false;

			UInt32 DeviceCount = 0;
			FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK;

			// Create new instance of the FTDI device class
			ftdi = new FTDI();

			// Determine the number of FTDI devices connected to the machine
			ftStatus = ftdi.GetNumberOfDevices( ref DeviceCount );

			// Check status
			if(ftStatus != FTDI.FT_STATUS.FT_OK || DeviceCount == 0)
			{
				commStat = CommStatus.NoDevice;
				return;
			}

			commStat = CommStatus.NoElev8;

			// Allocate storage for device info list
			FTDI.FT_DEVICE_INFO_NODE[] DeviceList = new FTDI.FT_DEVICE_INFO_NODE[DeviceCount];

			try
			{
				// Populate our device list
				ftStatus = ftdi.GetDeviceList( DeviceList );

				bool FoundElev8 = false;
				for(int i = 0; i < DeviceCount && FoundElev8 == false; i++)
				{
					if(DeviceList[i].Type != FTDI.FT_DEVICE.FT_DEVICE_X_SERIES) continue;

					for(int baud = 0; baud < 2; baud++)
					{
						ftStatus = ftdi.OpenBySerialNumber( DeviceList[i].SerialNumber );
						if(ftStatus == FTDI.FT_STATUS.FT_OK)
						{
							string portName;
							ftdi.GetCOMPort( out portName );
							if(portName == null || portName == "")
							{
								ftdi.Close();
								continue;
							}

							if(baud == 0) {
								ftdi.SetBaudRate( 115200 );	// try this first
							}
							else {
								ftdi.SetBaudRate( 57600 );	// then try this (xbee)
							}

							ftdi.SetDataCharacteristics( 8, 1, 0 );
							ftdi.SetFlowControl( FTDI.FT_FLOW_CONTROL.FT_FLOW_NONE, 0, 0 );


							txBuffer[0] = (byte)'E';
							txBuffer[1] = (byte)'l';
							txBuffer[2] = (byte)'v';
							txBuffer[3] = (byte)'8';
							uint written = 0;

							for(int j = 0; j < 10 && FoundElev8 == false && !quit; j++)	// Keep pinging until it replies, or we give up
							{
								ftdi.Write( txBuffer, 4, ref written );
								System.Threading.Thread.Sleep( 50 );

								uint bytesAvail = 0;
								ftdi.GetRxBytesAvailable( ref bytesAvail );				// How much data is available from the serial port?
								if(bytesAvail > 0)
								{
									int TestVal = 0;

									while(bytesAvail > 0 && !quit)
									{
										uint bytesRead = 0;
										ftdi.Read( rxBuffer, 1, ref bytesRead );
										if(bytesRead == 1)
										{
											TestVal = (TestVal << 8) | rxBuffer[0];
											if(TestVal == (int)(('E' << 0) | ('l' << 8) | ('v' << 16) | ('8' << 24)) )
											{
												FoundElev8 = true;
												commStat = CommStatus.Connected;
												break;
											}
										}

										if(bytesRead == 0) break;
									}
								}
							}

							if(FoundElev8)
							{
								connected = true;
								if(ConnectionStarted != null) {
									ConnectionStarted();
								}
								break;
							}
							else
							{
								ftdi.Close();
							}
						}
					}
				}
			}

			catch(Exception)
			{
				return;
			}
		}