Future Technology Devices International Ltd
USB TO RS422 UART SERIAL CONVERTER PCB
Datasheet
Document Reference No.: FT_000119
Version 1.02
Issue Date: 13-04-09
Future Technology Devices International Limited (FTDI)
Unit1, 2 Seaward Place, Centurion Business Park,, Glasgow G41 1HH United Kingdom
Tel.: +44 (0) 141 429 2777 Fax: + 44 (0) 141 429 2758
E-Mail (Support): support1@ftdichip.com Web: http://www.ftdichip.com
Copyright © 2008 Future Technology Devices International Limited
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. No freedom to use patents or other intellectual property rights is implied by
the publication of this document. Future Technology Devices International Ltd, Unit1, 2 Seaward Place, Centurion Business Park,
Glasgow, G41 1HH, United Kingdom. Scotland Registered Number: SC136640
Copyright © 2009 Future Technology Devices International Limited
Document Reference No.: FT_000119
USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
Version 1.02
Clearance No.: FTDI#79
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Description
The USB-RS422-PCB is a USB to RS422 level serial UART converter PCB incorporating FTDI’s FT232RQ
USB to Serial UART interface IC device which handles all the USB signalling and protocols. The PCB
provides a fast, simple way to connect devices with a RS422 interface to USB.
Each USB-RS422-PCB contains a small internal electronic circuit board, utilising the FT232R plus a USB
type-A connector. The FT232R datasheet, DS_FT232R, is available at http://www.ftdichip.com. The
integrated electronics also include an RS422 transceiver plus Tx and Rx LEDs which give a visual
indication of UART traffic.
The PCB is USB powered and USB 2.0 full speed compatible. Each PCB supports a data transfer rate up to
3 Mbaud and supports the FTDIChip-ID™, with a unique USB serial number programmed into the
FT232R. This feature can be used to create a security or password protected file transfer access using the
PCB. Further information and examples on this feature are available at http://www.ftdichip.com under
FTDIChip-ID Projects.
The USB-RS422-PCB requires USB drivers, available free from http://www.ftdichip.com, which are
used to make the FT232R on the PCB appear as a virtual COM port (VCP). This then allows the user to
communicate with the USB interface via a standard PC serial emulation port (for example TTY). Another
FTDI USB driver, the D2XX driver, can also be used with application software to directly access the
FT232R on the PCB though a DLL. This is illustrated in the Figure 1.1.
Figure 1.1 Using the USB-RS422-PCB
1.1 Part Number
The following Table 1.1 gives details of the available USB-RS422-PCB.
Part Number
Description
USB-RS422-PCB
USB to RS422 level UART PCB
Table 1.1 USB-RS422-PCB Part Number
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Table of Contents
1
Description ..................................................................................... 1
1.1
2
Part Number.................................................................................................. 1
Typical Applications ........................................................................ 3
2.1
Driver Support .............................................................................................. 3
2.2
Features ........................................................................................................ 4
3
Features of FT232R applicable to USB-RS422-PCB ......................... 5
4
USB-RS422-PCB Connector Pin Out and Mechanical details ............ 6
4.1
USB-RS422-PCB Signal Descriptions ............................................................. 8
4.2
USB-RS422-PCB Electrical Parameters .......................................................... 8
5
USB-RS422-PCB Circuit Schematic ............................................... 10
6
Contact Information ..................................................................... 11
Appendix A - PCB EEPROM Configuration ........................................... 13
Appendix B - List of Figures and Tables.............................................. 14
Appendix C - Revision History ............................................................ 15
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Typical Applications
•
USB to Serial RS422 Level Converter.
•
USB Instrumentation PC interface.
•
Upgrading Legacy Peripherals to USB.
•
USB Industrial Control.
•
Interface Microcontroller UART or I/O to USB.
•
USB password protected file transfers.
•
Interface FPGA / PLD to USB.
2.1 Driver Support
Royalty free VIRTUAL COM PORT
Royalty free D2XX Direct Drivers
(VCP) DRIVERS for...
(USB Drivers + DLL S/W Interface)
•
Windows 98, 98SE, ME, 2000, Server 2003 and
Server 2008
•
Windows 98, 98SE, ME, 2000, Server 2003 and
Server 2008
•
Windows XP and XP 64-bit
•
Windows XP and XP 64-bit
•
Windows Vista and Vista 64-bit
•
Windows Vista and Vista 64-bit
•
Windows XP Embedded
•
Windows XP Embedded
•
Windows CE 4.2, 5.0 and 6.0
•
Windows CE 4.2, 5.0 and 6.0
•
Mac OS 8/9, OS-X
•
Linux 2.4 and greater
•
Linux 2.4 and greater
•
Mac OS-X
The drivers listed above are all available to download for free from www.ftdichip.com. Various 3rd
Party Drivers are also available for various other operating systems - see www.ftdichip.com for details.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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2.2 Features
•
USB-RS422-PCB provides a USB to RS422
Serial UART interface.
•
Support for FT232R FTDIChip-ID™ feature for
improved security.
•
Entire USB protocol handled by the electronics
on the PCB.
•
PCB is USB Powered - no external supply
required.
•
EIA/TIA-422 interface with low power
requirements.
•
Low USB bandwidth consumption.
•
UHCI / OHCI / EHCI host controller compatible.
•
UART interface support for 7 or 8 data bits, 1
or 2 stop bits and odd / even / mark / space /
no parity.
•
USB 2.0 Full Speed compatible.
•
-40°C to +85°C operating temperature range.
•
RoHS compliant
•
ESD Protection for RS-422 I/O's
±15kV Human Body Model (HBM)
±15kV EN61000-4-2 Air Gap Discharge
±8kV EN61000-4-2 Contact Discharge
•
Data transfer rates from 300 baud up to 3
Mbaud.
•
Internal EEPROM with user writeable area.
•
FTDI’s royalty-free VCP allow for
communication as a standard emulated COM
port and D2XX ‘direct’ drivers provide DLL
application programming interface.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Features of FT232R applicable to USB-RS422-PCB
The USB-RS422-PCB uses FTDI’s FT232RQ USB to serial IC device. This section summarises the key
features of the FT232RQ which apply to the USB-RS422-PCB. For further details, and a full features and
enhancements description consult the FT232R datasheet, this is available from www.ftdichip.com.
Internal EEPROM. The internal EEPROM is used to store USB Vendor ID (VID), Product ID (PID), device
serial number, product description string and various other USB configuration descriptors. Each FT232RQ
is supplied with the internal EEPROM pre-programmed as described in Appendix A - PCB EEPROM
Configuration. The internal EEPROM descriptors can be programmed in circuit, over USB without any
additional voltage requirement. It can be programmed using the FTDI utility software called MPROG,
which can be downloaded from FTDI Utilities on the FTDI website (www.ftdichip.com). Additionally, there
is a user area of the internal EEPROM available to system designers to allow storing of data (note that
this is not modified by MPROG).
Lower Operating and Suspend Current. The FT232R has a low 15mA operating supply current and a
very low USB suspend current of approximately 70µA.
Low USB Bandwidth Consumption. The USB interface of the FT232R, and therefore the USB-RS422PCB has been designed to use as little as possible of the total USB bandwidth available from the USB host
controller.
FTDIChip-ID™. The FT232R includes the new FTDIChip-ID™ security dongle feature. This FTDIChip-ID™
feature allows a unique number to be burnt into each FT_232RQ during manufacture. This number cannot
be reprogrammed. This number is only readable over USB can be used to form the basis of a security
dongle which can be used to protect any customer application software being copied. This allows the
possibility of using the USB-RS422-PCB as a dongle for software licensing. Further to this, a renewable
license scheme can be implemented based on the FTDIChip-ID™ number when encrypted with other
information. This encrypted number can be stored in the user area of the FT232R internal EEPROM, and
can be decrypted, then compared with the protected FTDIChip-ID™ to verify that a license is valid. Web
based applications can be used to maintain product licensing this way. An application note, AN232R-02,
available from FTDI website (www.ftdichip.com) describes this feature.
Extended Operating Temperature Range - The USB-RS422-PCB is capable of operating over an
extended temperature range of -40º to +85ºC thus allowing it to be used in automotive or industrial
applications.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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USB-RS422-PCB Connector Pin Out and Mechanical details
RED
LED
TOP
GRN
LED
RS 422
Tranceiver
TXDTXD+
GND
RS 422
Tranceiver
RTSRTS+
GND
CTS-
BOTTOM
FT232R
CTS+
RXDRXD+
USB-RS422-PCB REV 2
Figure 4.1 USB-RS422-PCB Pin Out (Top is TOP View, Bottom is BOTTOM View)
The mechanical details of the PCB are shown in the following diagram Figure 4.2
The pads were re-arranged on the PCB to allow for easier wiring which resulted in a Rev 2 PCB. There
were no other changes between Rev 1 and Rev 2.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Figure 4.2 USB-RS422-PCB, Mechanical Details
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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4.1 USB-RS422-PCB Signal Descriptions
Name
Type
Description
GND
GND
Device ground supply pin.
CTS+
Input
Clear to Send Control + (B), Input
TXD-
Output
Data – (A) Output
TXD+
Output
Data + (B) Output
RXD+
Input
RTS+
Output
Request To Send Control + (B), Output
RTS-
Output
Request To Send Control – (A), Output
RXD-
Input
Data – (A) Input
CTS-
Input
Clear to Send Control input – (A), Input
Data + (B) Input
Table 4.1 USB-RS422-PCB Signal Descriptions
4.2 USB-RS422-PCB Electrical Parameters
Parameter
Description
Minimum
Typical
Maximum
Units
+12
V
Conditions
Receiver Input
VCM
Common-mode input
voltage range
-7
1.0
IN
Input Current
VIN = +12V
mA
–0.8
VTH
VIHYST
RIN
DIfferential Threshold
Voltage,VTH
-0.2
Input Hysteresis
Input Resistance, RIN
12
+0.2
VIN = –7V
V
20
mV
15
kΩ
Transmitter Output
VOD
DIfferential Output Voltage,
dVOD
1.5
5
V
With RL = 54Ω. CL = 50pF *
Table 4.2 USB-RS422-PCB I/O Characteristics
* - The 54 ohms is the equivalent of two 120 ohm termination resistors placed on each side of the
transmission line and the input impedance of 32 receivers on the line.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Description
Conditions
Minimum
Typical
ESD HBM
RS-422 Inputs and Outputs
±15 kV
EN61000-4-2ContactDischarge
RS-422 Inputs and Outputs
±8 kV
EN61000-4-2AirGapDischarge
RS-422 Inputs and Outputs
±15 kV
Maximum
Table 4.3 USB-RS422-PCB ESD Tolerance
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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USB-RS422-PCB Circuit Schematic
The circuit schematic of the USB-RS422-PCB, utilising the FTDI FT232R, is shown in Figure 5.1
Figure 5.1 Circuit Schematic of USB-RS422-PCB.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Contact Information
Head Office – Glasgow, UK
Future Technology Devices International Limited
Unit 1, 2 Seaward Place, Centurion Business Park
Glasgow G41 1HH
United Kingdom
Tel: +44 (0) 141 429 2777
Fax: +44 (0) 141 429 2758
E-mail (Sales) sales1@ftdichip.com
E-mail (Support) support1@ftdichip.com
E-mail (General Enquiries) admin1@ftdichip.com
Web Site URL http://www.ftdichip.com
Web Shop URL http://www.ftdichip.com
Branch Office – Shanghai, China
Future Technology Devices International Limited (China)
Room 408, 317 Xianxia Road,
ChangNing District,
ShangHai, China
Tel: +86 (21) 62351596
Fax: +86(21) 62351595
E-Mail (Sales): cn.sales@ftdichip.com
E-Mail (Support): cn.support@ftdichip.com
E-Mail (General Enquiries): cn.admin1@ftdichip.com
Web Site URL: http://www.ftdichip.com
Branch Office – Taipei, Taiwan
Future Technology Devices International Limited (Taiwan)
2F, No. 516, Sec. 1, NeiHu Road
Taipei 114
Taiwan , R.O.C.
Tel: +886 (0) 2 8797 1330
Fax: +886 (0) 2 8751 9737
E-mail (Sales)
tw.sales1@ftdichip.com
E-mail (Support)
tw.support1@ftdichip.com
E-mail (General Enquiries) tw.admin1@ftdichip.com
Web Site URL
http://www.ftdichip.com
Branch Office – Hillsboro, Oregon, USA
Future Technology Devices International Limited (USA)
7235 NW Evergreen Parkway, Suite 600
Hillsboro, OR 97123-5803
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987
E-Mail (Sales)
us.sales@ftdichip.com
E-Mail (Support) us.admin@ftdichip.com
Web Site URL
http://www.ftdichip.com
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) and
sales representative(s) in your country.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Appendix A - PCB EEPROM Configuration
Each USB-RS422-PCB is controlled by the FTDI FT232R IC. This FT232R device contains an EEPROM which
contains the USB configuration descriptors for that device. When the PCB is plugged into a PC or a USB
reset is performed, the PC will read these descriptors. The default values stored into the internal EEPROM
are defined in Table 0.1 Default Internal EEPROM Configuration
Parameter
Value
USB Vendor ID (VID)
0403h
FTDI default VID (hex)
USB Product UD (PID)
6001h
FTDI default PID (hex)
Serial Number Enabled?
Serial Number
Pull down I/O Pins in USB
Suspend
Yes
See Note
A unique serial number is generated and programmed into
the EEPROM during device final test.
Disabled
Enabling this option will make the device pull down on the
UART interface lines when the power is shut off (PWREN#
is high).
Manufacturer Name
FTDI
Product Description
See note
Max Bus Power Current
Power Source
Device Type
USB Version
Notes
USB-RS422-PCB
90mA
Bus Powered
FT232R
0200
Returns USB 2.0 device description to the host.
Note: The device is be a USB 2.0 Full Speed device
(12Mb/s) as opposed to a USB 2.0 High Speed device
(480Mb/s).
Remote Wake Up
Disabled
High Current I/Os
Enabled
Load VCP Driver
Enabled
Invert TXD
Disabled
Signal on this pin becomes TXD# if enable.
Invert RXD
Disabled
Signal on this pin becomes RXD# if enable.
Invert RTS#
Disabled
Signal on this pin becomes RTS if enable.
Invert CTS#
Disabled
Signal on this pin becomes CTS if enable.
Enables the high drive level on the UART and CBUS I/O
pins.
Makes the device load the VCP driver interface for the
device.
Table 0.1 Default Internal EEPROM Configuration
The internal EEPROM on the PCB can be re-programmed over USB using the utility program MPROG.
MPROG can be downloaded from the www.ftdichip.com. Version 2.8a or later is required for the FT232R
chip. Users who do not have their own USB Vendor ID but who would like to use a unique Product ID in
their design can apply to FTDI for a free block of unique PIDs. Contact FTDI support for this service.
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Clearance No.: FTDI#79
Appendix B - List of Figures and Tables
List of Figures
Figure 1.1 Using the USB-RS422-PCB........................................................................................................... 1
Figure 4.1 USB-RS422-PCB Pin Out (Top is TOP View, Bottom is BOTTOM View).................................. 6
Figure 4.2 USB-RS422-PCB, Mechanical Details .......................................................................................... 7
Figure 5.1 Circuit Schematic of USB-RS422-PCB. ..................................................................................... 10
List of Tables
Table 1.1 USB-RS422-PCB Part Number ....................................................................................................... 1
Table 4.1 USB-RS422-PCB Signal Descriptions ........................................................................................... 8
Table 4.2 USB-RS422-PCB I/O Characteristics ............................................................................................. 8
Table 4.3 USB-RS422-PCB ESD Tolerance ................................................................................................... 9
Table 0.1 Default Internal EEPROM Configuration..................................................................................... 13
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USB TO RS422 UART SERIAL CONVERTER PCB Datasheet
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Appendix C - Revision History
Version Draft
First Draft
January 2009
Version 1.0
First Release
21st January 2009
Version 1.01
Corrected the PCB drawing and TW address
09th February 2009
Version 1.02
Added rev1 and rev2 PCB drawings
13th April 2009
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