This product is currently under development!

USB to Quad RS-485 Conv. Module

This product is USB to 4 RS-485 conversion module. The FTDI FT4232H is used for USB to quad UART conversion, and the Analog Devices ADM3078E is used for UART to RS-485 conversion. USB is 2.0 High Speed (480 Mb/s) and RS-485 supports a maximum baud rate of 16 MBps. The RS-485 I/O voltage is 3.3 V and is supplied by USB bus power from the regulator on the board. This product has a internal EEPROM and programmable in-circuit over USB using a utility program called FT_PROG available from FTDI’s web site (www.ftdichip.com).

Note: For this product, RI must be RS485 enabled (Enables the RI pin to be used as the TXDEN signal for RS485 busses) using FT_PROG in order to convert USB to RS-485 for transmission.

Features Rev. 1

Top Surface of PCB	Bottom Surface of PCB	Assembled Electronic Components

PCB

• 58 mm x 22.5 mm PCB layout
• Two types of USB connectors
  • USB Mini-B Connector
  • 1" (2.54mm) pitch through-holes for pin headers
    • VBUS
    • DM: USB Data Signal Minus
    • DP: USB Data Signal Plus
    • GND: Common Ground
• 4 x RS-485 ports
  • 1" (2.54mm) pitch through-holes for pin headers
    • 3V3: 3.3 V power output (Power generated by the regulator on the board from USB bus power)
    • DP: RS-485 Data Signal Plus
    • DM: RS-485 Data Signal Minus
    • GND: Common Ground
• 1 x Expansion port for FTDI FH4232HQ
  • 1" (2.54mm) pitch through-holes for pin headers
    • 3V3: 3.3 V power output (Power generated by the regulator on the board from USB bus power)
    • PWREN: Connected to FT4232HQ Pin#: 60 PWREN#
    • CLK: Connected to FT4232HQ Pin#: 62 EECLK
    • CS: Connected to FT4232HQ Pin#: 63 EECS
    • DATA: Connected to FT4232HQ Pin#: 61 EEDATA
    • GND: Common Ground
    This port can be used for 4-channel transmit/receive LED display by decoding EEDATA data using 74HCT595, etc. Check the Data Sheet for details.

Development Environments

This product is designed with the following software.

• Autodesk Eagle 9.6.2

Repository Contents

\images

PCB preview images and capture of design screen

\libraries

Libraries used in Autodesk Eagle design

\pcb_order

Gerber data and documentation for ordering PCB

schematic.pdf

Circuit diagram of this product

*.brd

Board wiring design file by Autodesk Eagle

*.sch

Circuit diagram design file by Autodesk Eagle

.gitignore

A file that tells Git not to track a particular file

LICENSE

License to use this product

Documentation

The following documents are available for this product.

• \pcb_order\README.md: Information for ordering the PCB

References

This product was designed with reference to the following products.

• FTDI USB Hi-Speed FT4232H Evaluation Module: FT4232H Mini Module
• KONDO RS485USB/Serial Conversion Adapter

In addition, the following documents were referenced in the design

• FTDI USB Hardware Design Guidelines for FTDI ICs
• Analog Devices Safeguard Your RS-485 Communication Networks from Harmful EMC Events
• KONDO B3M Series Manual Ver1.13 pp.8

Acknowledgements

The background to the development of this product was the development of QUADDXL, which was introduced in the following paper.

• Bestmann, M., Güldenstein, J., Zhang, J. : High-Frequency Multi Bus Servo and Sensor Communication Using the Dynamixel Protocol. RoboCup 2019: Robot World Cup XXIII, pp.16–29 (2019)

Development data and other information on QUADDXL are available in the following repositories.

• bit-bots/bitbots_quaddxl: USB to RS485 Converter using FT4232H

I would like to take this opportunity to thank you.

Contact

If you have any questions, please contact the designer of this product, Masato Kubodera, by e-mail.
E-mail: [email protected]

License Information

This product is open source. Please review the LICENSE for license information.

This product by Masato Kubotera is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.