[evanperryg]

The MXPduino is in early development, here's a very, very basic prototype.
Features:

• on-board ATMEGA328 will be loaded with Arduino bootloader
• The ADC inputs on the 328 go directly to IOs on the MXP port, including 2 PWM-capable outputs, 2 I2C capable outputs, and 2 analog outs,
• Access to MXP DIOs 0-11, AIs 0-3, I2C, and UART
• Access to Arduino DIOs 2-13 and UART
• 2x4 header allows shared 5V power between the MXP and arduino, and makes it easy to connect/disconnect serial communication between the roboRIO and the ATMEGA328.
• Holes for secure mounting to the roboRio

Plans for Revision 2:

• Adjust placement of the interface header, MXP-UART header, and I2C header down into less crowded board space
• Add access to MXP DIO12, DIO13, AO0, and AO1, and header for Arduino analogs (although the addition of the MXP pins would do the same thing, a separate header that puts all 6 connections close together could be useful.
• Reduce space inefficiencies, especially at the bottom of the board

EDIT: some of the traces look a little nerfed in the screenshot. Ignore that, it's been fixed since the screenshot was made.