private static extern int ftdi_write_data(ref ftdi_context ftdi, Byte[] buf, int size);
private static extern int ftdi_usb_purge_tx_buffer(ref ftdi_context ftdi);
private static extern int ftdi_read_chipid(ref ftdi_context ftdi, ref int chipid);
private static extern int ftdi_usb_reset(ref ftdi_context ftdi);
private static extern int ftdi_write_data_set_chunksize( ref ftdi_context ftdi, UInt32 chunksize);
private static extern int ftdi_usb_open(ref ftdi_context ftdi, int vendor, int product);
private static extern int ftdi_usb_close(ref ftdi_context ftdi);
private static extern int ftdi_deinit(ref ftdi_context ftdi);