Future Technology Devices International Ltd. AN232R-04 Windows Combined Driver Model Copyright © 2006 Future Technology Devices International Ltd. 2 1 AN232C-04 Windows Combined Driver Model Introduction This document describes the Combined Driver Model (CDM) for the implementation of FTDI drivers on Windows 2000, Windows XP, Windows XP x64, Windows Server 2003 and Windows Server 2003 x64 operating systems. Copyright © 2006 Future Technology Devices International Ltd. Background 2 3 Background FTDI has evolved two types of driver for its ICs: VCP and D2XX. The VCP driver makes the device appear in the system as a serial port. Applications access the port using the Win32 COMM API as if it was a normal serial port. The driver consists of two layers: FTDIBUS and FTSER2K. FTDIBUS handles the creation of the serial port and access to the hardware and FTSER2K is the implementation of the serial port. These drivers communicate using the FTDIBUS class interface. The D2XX driver is used in situations where a serial port is not required. It allows access to the device via the proprietary D2XX API. The driver is implemented as a single layer, FTD2XX.SYS, and is normally accessed through the library FTD2XX.DLL. Copyright © 2006 Future Technology Devices International Ltd. 4 AN232C-04 Windows Combined Driver Model Copyright © 2006 Future Technology Devices International Ltd. Architecture 3 5 Architecture The key component of CDM is a new driver that supports D2XX and FTDIBUS class interfaces. The combined driver replaces FTD2XX and FTDIBUS, and an application can use either interface, although not both simultaneously. A feature of the newer FTDI devices (FT232R, FT245R and FT2232) is a configuration setting held in EEPROM that indicates what type of driver should be loaded for the device, thus determining the device type. This setting is read when the device is enumerated and determines whether a COM port is exposed or not. For example, if a device is programmed as D2XX then no COM port will be exposed for that device. In the case of older FTDI devices (AM and BM series) where there is not an EEPROM setting for driver type, a serial port will be exposed by default. This is to ensure compatibility with existing applications which could use either the D2XX or FTSER2K interface. Copyright © 2006 Future Technology Devices International Ltd. 6 AN232C-04 Windows Combined Driver Model The EEPROM settings can be overridden by changing the driver INF files or by changing the "Load VCP" option on the Advanced tab of the USB Serial Converter property page (see AN232B10 Advanced Driver Options). Please note that CDM 2.00.00 is Microsoft WHQL certified and changing any of the files in the driver package, including INF and INI files, invalidates the certification. Copyright © 2006 Future Technology Devices International Ltd. Advantages 4 7 Advantages The main advantages to using the CDM driver are: · A single driver package removes uncertainty over which driver to install. · CDM 2.00.00 is Microsoft WHQL certified for Windows 2000, Windows XP, Windows Server 2003, Windows XP x64 and Windows Server 2003 x64. This provides a Microsoft WHQL certified D2XX interface which has not been available before CDM. · CDM is compatible with driver pre-installation tools such as DPInst (see AN232R03 FTDI Windows Driver Pre-Installation). FTDI provide the certified CDM driver as an executable which uses DPInst to install the drivers (see http://www.ftdichip.com/Drivers/VCP.htm). · No longer a need to uninstall VCP drivers and install D2XX drivers to reprogram device EEPROMs. So long as only one application is communicating with the device, either interface can be used. Copyright © 2006 Future Technology Devices International Ltd. 8 5 AN232C-04 Windows Combined Driver Model Document Revision History Version Release Date Comments 1.0 June 2006 Initial release. Copyright © 2006 Future Technology Devices International Ltd. Disclaimer 6 9 Disclaimer Copyright © 2006 Future Technology Devices International Ltd. Neither the whole nor any part of the information contained in, or the product described in this manual, may be adapted or reproduced in any material or electronic form without the prior written consent of the copyright holder. This product and its documentation are supplied on an as-is basis and no warranty as to their suitability for any particular purpose is either made or implied. Future Technology Devices International Ltd. will not accept any claim for damages howsoever arising as a result of use or failure of this product. Your statutory rights are not affected. This product or any variant of it is not intended for use in any medical appliance, device or system in which the failure of the product might reasonably be expected to result in personal injury. This document provides preliminary information that may be subject to change without notice. Copyright © 2006 Future Technology Devices International Ltd. 10 7 AN232C-04 Windows Combined Driver Model Contact Information Head Office - Glasgow, UK Future Technology Devices International Limited 373 Scotland Street Glasgow G5 8QB United Kingdom Tel: +44 (0) 141 429 2777 Fax: +44 (0) 141 429 2758 E-Mail (Sales): [email protected] E-Mail (Support): [email protected] E-Mail (General Enquiries): [email protected] Web Site URL: http://www.ftdichip.com Web Shop URL: http://apple.clickandbuild.com/cnb/shop/ftdichip Branch Office - Taiwan Future Technology Devices International Limited (Taiwan) 4F, No 16-1, Sec. 6 Mincyuan East Road Neihu District Taipei 114 Taiwan ROC Tel: +886 2 8791 3570 Fax: +886 2 8791 3576 E-Mail (Sales): [email protected] E-Mail (Support): [email protected] E-Mail (General Enquiries): [email protected] Web Site URL: http://www.ftdichip.com Branch Office - Hillsboro, Oregon, USA Future Technology Devices International Limited (USA) 5285 NE Elam Young Parkway Suite B800 Hillsboro, OR 97124-6499 USA Tel: +1 (503) 547-0988 Fax: +1 (503) 547-0987 E-Mail (Sales): [email protected] E-Mail (Support): [email protected] E-Mail (General Enquiries): [email protected] Web Site URL: http://www.ftdichip.com Agents and Sales Representatives Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) in your country. Copyright © 2006 Future Technology Devices International Ltd. Index Index -CCDM 2, 3, 5, 7, 8, 9, 10 Combined Driver Model 2, 3, 5, 7, 8, 9, 10 Copyright © 2006 Future Technology Devices International Ltd. 11