Coduino

The Coduino will be an Arduino-compatible CPU/support on a shield, to enable multiprocessor stacks. It may also be made in multi-CPU version (2 or 4 CPUs on a shield) for really cool projects.

• Will use ATMega328p for compatibility with the Duemilanove board.
• Standard bootloader will be used.
• Serial only in the first revision, no USB-Serial on the board itself (FTDI cables are easy to get now).
• Will communicate with the master Arduino (bottom of the stack) via I2C, leaving all other pins available.
• Main headers will just 'stack-through' the master Arduino, the I/O from the Coduino will be broken out on separate headers (maybe with a 'base board' that can connect to stack shields on the Coduino via a cable?).
• Board could have capability for 1, 2, or 4 (or 3 really, but I like more even numbers) processors, and just get stuffed with the desired number for cost control.
• Local voltage regulation would be best so as to not overload the master's regulator. Power can be pulled from the Vin pin (as long as this has power when using USB or DC) and regulated with a single local regulator for the whole board.