Copyright © 2009 Future Technology Devices International Limited 3
Document Reference No.: FT_000160
FTDI Drivers Installation guide for Windows 7
Application Note AN_119 Version 1.0
Clearance No.: FTDI# 120
2 Installing FTDI Device Drivers
FTDI have previously provided two types of driver for Windows OS: a D2XX direct driver and a virtual
COM port (VCP) driver. Previously, these drivers were mutually exclusive and could not be installed at the
same time. The new Windows combined driver model (CDM) which may be installed on Windows 2000,
XP, VISTA or Windows 7 allows applications to access FTDI devices through either the D2XX DLL or a
COM port without having to change driver type. However, it should be noted that an application can only
communicate through one of these interfaces at a time and cannot send commands to the D2XX DLL and
the associated COM port at the same time.
The CDM driver comes in two parts. The first part is the bus layer that provides D2XX style functionality
and is always installed. The second part is the serial COM port layer and the CDM driver will determine
whether a COM port should be exposed by reading the EEPROM of FT232R, FT245R, FT2232D, FT2232H
and FT4232H devices. In the case of FT232BM, FT245BM, devices, the CDM driver will default to always
installing a COM port.
This behavior can be changed and EEPROM settings ignored by changing the driver INF files as detailed in
FTDI Application Note AN-107, Advanced Driver Options. Please note that modifying the INF files of a
Microsoft WHQL certified driver will invalidate the Windows certification.
The driver is downloadable from the FTDI website by clicking the word download: download.
