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Table of Contents
Microchip MCP2221
These are USB I2C/UART/GPIO bridges which can achieve 115200 baud.
Since they are available in a DIP package they are very easy to utilise.
Schematic
LED demo
A simple utility named Dougal has been written to query the MCP2221 and also demonstrate how to bit-bang the GPIOs.
hg clone http://hg.kewl.org/pub/Dougal cd Dougal/src make sudo ./mcp2221 -b