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USB-I2C/IO Changes


Photo of USB-I2C/IO Rev. B2 boardPhoto of USB-I2C/IO Rev. C1 board
USB-I2C/IO P.C.B.s (Rev. B2 on left, Rev. C1 on right)

What's the same?

The Rev. C1 board is nearly identical to the Rev. Bx boards in both form factor and function. It was our intention that the board would be as close to a "drop-in" replacement for the Rev. B boards as possible.

Physical Dimensions (2.25" X 3.0").
Location and size of mounting holes (0.150" from edges, 0.125 diameter hole).
Physical location of connectors and signals for USB-B, General Purpose I/O (J2), and I2C (J4)connectors.
The API.  The Revision C1 board firmware (version 5.) is a port of the Revision B firmware (version 3.7).

What's different?

The Rev. C1 board has been enhanced in an effort to provide more features and some additional protection.

It's red! The Rev. C1 board uses red solder mask to make it easy to distinguish between Rev. C1 and Rev. Bx boards (which are blue).
It's RoHS compliant (lead free)!  We may have some documentation and/or labeling work to do, but the p.c.b., all components, and the assembly process, all conform to the requirements.
Changed the micro-controller from the obsolete Cypress AN2131QC to the Silicon Labs C8051F340.  We are very excited about this new micro, as it solves a number of issues with the old micro, while providing greatly enhanced speed and functionality.
Changed the three voltage test-points from through-hole to surface mount.
Enhanced the ESD protection using 3 separate devices for USB D+/D-, I2C SCL/SDA signals, and Auxiliary connector signals.
Moved onboard I2C eeprom to it's own I2C bus segment to solve I2C address conflict issues.
Renamed "Breakpoint" LED function to "Error" for use as an error indicator.
Changed pin-out and function of the J1 header from "Debug" to "Auxiliary".  This header is intended to eventually provide for enhanced functionality, like a a second I2C channel, or possibly support for some 1-wire interfaces.  The Debug header was largely unused by customers, so we do not anticipate this change to be a problem for most customers.
Replaced the Data Bus signals on the J2 header with 8 more general purpose I/O pins.  These pins will eventually be configurable to support other configurable functions such as SPI bus, another I2C channel, etc.
Moved the configuration headers and jumpers around (see schematics for circuit details).


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Last modified: August 25, 2008