For PropBerry, I was thinking using a Parallax Propeller* (or just Prop) as a super i/o co-processor for the RPi where the Prop would be used to offload the real-time I/O and let the RPi handle the higher program features. After talking about this combo on the Parallax forums, the Props VGA video capabilities were mentioned which got me thinking about using the PropBerry as a VGA serial terminal console and shelve the i/o co-processor idea for now.
The Parallax community is great and they’ve released a lot of good stuff. One of the things I remember (from about 2009) was Vincent Briel’s PockeTerm terminal software for the Prop. Using this on a Propeller Demo Board gives us a VGA video output and PS/2 keyboard for user input. A serial interface connects the Propeller demo board to the Raspberry Pi.
* The Parallax P8X32A Propeller chip (or just Prop) is a cool chip. It is a multi-core architecture parallel microcontroller with eight 32-bit RISC CPU cores (cogs) which share a common hub of 32K-RAM