This is my first post after working with arduinos for almost 2 years. Arduino had taught me a lot and I am very thankful to the team that developed it.
I am in the process of making an I/O board with at least 100 usable I/O pins. It is easier to choose a hardware such as AVR32 but then, I would not be able to use the Arduino development platform.
For that matter, I am looking into making a single board design that consists of two ATmega1280 or two ATxmega (74 pin series).
Given the situation that ATxmega is in (lack of availability), I am sure the ATmega1280 would be my only option.
The idea is simple, put two ATmega1280 in one board, wire up the two microcontroller via I2C as described here so the two microcontroller can communicate if desired.
Next step is to figure out how to interface both microcontroller to an FTDI chip, so that a single RS232 interface is shared between the controllers, only for programming purposes.
While running, the two controller can use I2C to communicate. Several digital I/O lines (with selectable pull up / pull down operation )could also be connected for interrupt operation between the two microcontrollers.
I would really appreciate any inputs from everyone about the design and hope that I could contribute to the community this time.