userial

Index

Description
Documentation
Download
News
To Do

Description

userial is an Open Source project containing both Hardware and Software to build your own USB to I2C bridge. It uses an Atmel AT90USB647 chip. It supports the following interfaces:

• USB interface (serial emulation)
• JTAG
• I2C (TWI)
• SPI (currently no firmware support)
• 8 General purpose digital I/O (firmware support in v1.3)
• 4 Analog to Digital converters (currently no firmware support)

The board communicates with the host computer using a CDC (USB communications device class). This makes it easy to use userial without installing a device driver or special libraries. Due to the ASCII based command interface it is easy to control devices manually with just a terminal emulation. This makes it easy to obtain quick results, to configure devices on-the-fly or to control prototyping boards in a straight-forward way.

Schematics and firmware are available to the public. The firmware is released under the terms of the MIT license and the hardware is released under the terms of the Creative Commons Attribution-Share Alike 3.0 Unported License.

Documentation

• User guide in HTML format
• User guide in PDF format

Download

• Firmware (v1.4, compatible with hardware v1.0)
• Schematic as PDF (v1.0)
• Schematic as PNG (v1.0)
• Eagle source files (v1.0)
• Gerber files (v1.0)

News

Firmware v1.4   (16 December 2008)
userial firmware v1.4 released. This version fixes a few bugs and contains minor improvements:

• Fixed a bug in the Ack/Nack signal handling on master read operations.
• Made the command handler more robust. Now it is possible to send commands in batch mode.
• Added new command '#' (comment line).
• Updated LUFA library to version 081217.

Firmware v1.3   (07 December 2008)
userial firmware v1.3 released. This version contains a few improvements:

• Added GPIO support.
• Fixed a bug in the calculation of the I2C frequency calculator.
• Reduced RAM footprint.
• Relicensed the source code under the terms of the MIT licence.

Firmware v1.2   (26 November 2008)
userial firmware v1.2 released. Fixed a bug in the command parser. After an error the response was delayed.

Firmware v1.1   (14 November 2008)
userial firmware v1.1 released. Added settings for I2C speed.

Firmware v1.0   (31 August 2008)
userial firmware v1.0 released.

To Do

• FW: There is a bug in the firmware that prevents packets of 5 bytes to be sent immediately. The packet is queued and sent on the next USB transmission.
• FW: Support for ADC and SPI.
• HW: Use ATmega32U4—if and when it becomes available—for a new hardware design.