The WR703N Expander is a compact PCB providing a 4 port USB hub and dual FTDI serial ports, with additional GPIO. It is perfect for use with the small TP-Link WR703N Linux based wireless router, or with almost any computer with USB (e.g. PC, Raspberry Pi, BBB, etc). The USB hub makes it easy to add a USB flash drive to expand the routers internal flash storage, and provide connection of additional USB devices (webcam, keyboard, sound, co-processor, etc), while the serial ports and GPIO allow versatile connectivity to other devices.
It was designed by
Kean Electronics in conjunction with
Robots & Dinosaurs for control and automation projects, and has been used in various designs such as robotics, smart LED lighting control, and wireless sharing of quadcopter webcams.
Features
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Compact size - designed to piggy back above WR703N router PCB
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Uplink USB port can be via mini-B, or 4 pin header to connect to WR703N
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3 available USB ports with alternate connection options (4 pin header or USB A female)
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2 FTDI virtual COM (serial) ports – using common 6 pin FTDI pinout (with RTS/CTS)
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Selectable 3.3V or 5V I/O voltages for Port A and Port B
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8 GPIO (part of Port A) – see GPIO pinout below
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EEPROM for use with FTDI FT_PROG configuration utility
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Incorporates FTDI MPSSE functions – allows SPI/I2C/JTAG emulation (e.g. see FTDI App Note AP_135)
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Can be powered from WR703N, or supply power to WR703N (short R113 on router)
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Works with most operating systems (FTDI driver required)
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Open source hardware design
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Info on OpenWRT and the WR703N available at http://wiki.openwrt.org/toh/tp-link/tl-wr703n and http://www.madox.net/blog/projects/tp-link-tl-wr703n/
Important
Note this unit does not include the TP-Link WR703N router
Specification
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Uses Genesys Logic GL850G USB hub IC, and FT2232L dual serial IC
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Connectors for USB and I/O come separately to allow end user customisation
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Weight: approx 7g-20g (depending on connectors installed)
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Size: 48x50x3mm (without connectors)
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PDF Schematic
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Eagle design files SCH & BRD
GPIO pinout (OC = Open Collector)
J1 pin FT2232 name VCP function (Port A)
1 ADBUS4 / GPIOL0 DTR# (out)
2 ADBUS5 / GPIOL1 DSR# (in)
3 ADBUS6 / GPIOL2 DCD# (in)
4 ADBUS7 / GPIOL3 RI# (in)
5 ACBUS0 / GPIOH0 TXDEN (out)
6 ACBUS1 / GPIOH1 SLEEP# (out)
7 ACBUS2 / GPIOH2 RXLED# (OC out)
8 ACBUS3 / GPIOH3 TXLED# (OC out)
9 5V - note above pins use logic voltage set by JMP3 (VCCA)
10 GND
