The bare board came back from from OSH Park late last week. I built the first board up over the weekend and am now testing and bringing the board up. The 3.3V and 5V power supplies are working. The firmware for step pulse generation is working and the I/O from the microcontroller is configured correctly. The driver microstep configuration, chop current and sleep enables are controlled by chips on the I2C bus and I am still having trouble with the I2C driver. Once that is working, it should move motors with the simple test firmware that I have written so far. It may be simpler to write my own driver from scratch than to debug the vendor supplied one. Still need to check out the limit switch input conditioning circuits and RS232 level shifters on the board. These are both blocks that I have used on similar boards in the past, so I don't expect problems on them.