7i76e Expansion Ports

Hello,

The 7i76e also has two "Expansion ports". I don't really understand them fully.

I do understand they're some kind of GPIO pins for the FPGA and can be configured with the right VHDL or similar, or I can purchase some kind of cards from Mesa that interface and use something pre-built.

Is there something I can find something akin to the 7i75 breakout card that offers protection circuitry that I can use, but probably not from Mesa?

And what limitations am I stuck with using a breakout card versus say the 7i85 if I wanted to have, as an example, MPG input? (I'm aware there's two dedicated MPG inputs on the 7i76e already, but say I wanted 3 MPGs after watching a certain This Old Tony video)

Thanks

You can use generic parallel port breakouts with the 7I76E