[Alan Anderson]

The OI is designed to accept two kinds of inputs. One is a variable resistor from ~2K to ~100K ohms; that's what the joysticks are. The other is a contact closure to ground; that's what the buttons are. You can provide a voltage between 0 and +5 volts on the joystick input pin and have it work.

There is absolutely no programming involved in connecting things to the OI. It is what it is, and we can't change how it works.

For a rotation input, a simple potentiometer will work. If the control needs to spin continuously, use a pot without an end stop. There is some programming you can do here, to accommodate the sudden jump from one end of the scale as the potentiometer wraps around. If your rotation rate is slow enough, you might be able to get away with using a quadrature sensor and a pair of digital inputs, but I wouldn't count on it.