GPIO to Spare? SPI? I2C?

[HalleysCometMan]

Finally got myself an arcade cab for my mister project and the first idea that springs to mind is....

Wouldn't it be nice to put digital pots in place of some of the controls on monitor chassis and have them settable when launching a core. Mainly width and height,

Had a quick browse around, and thinking this kind of thing should do the trick, though admittedly I know nothing about what spanners the intricacies of an arcade chassis might through into the equation. 6 Channels seems like a good start, maybe even enough for rgb gains.

https://docs.arduino.cc/tutorials/commu ... PotControl

Question is, what's the smartest way to interface with the nano and get access to?

I can see the nano technically can do SPI and I2C, though I can't really get much of an idea of what things are accessible to us who may want to extend functions.

Serial over spare GPIOs?

Or is it going to wind up making things easier to put the communication over TCP?

[caad]

Whatever you do, use optical isolation to protect your MiSTer.

The circuits of a CRT are not friendly to sensitive equipment like the DE-10. Even if the remote board is lower voltage (i.e. not 20kV) I would never want to risk it...

So first design a way to control the remote board using optocoupled inputs, maybe experiment with an Arduino... then move on to interfacing with the DE-10. Imho.