Hi all,

I picked up an original Philips CD-i Roller Controller (22ER9012) and would like to use it with the CD-i core on MiSTer FPGA. Rather than going the SNAC level-shifting route (which the CD-i core’s SNAC documentation flags as potentially problematic for some pointing devices due to voltage-level mismatches), I’m considering converting it into a standard USB HID mouse instead.

The idea: tap the trackball’s quadrature signals directly from the optical encoders (bypassing the original CD-i serial protocol entirely) and feed them into a small microcontroller (Arduino Pro Micro/Leonardo) running USB HID mouse firmware. That way it would work as a plug-and-play USB mouse — usable in the CD-i core via a regular USB port, and also on a PC for things like ScummVM.

Before I start cutting into the PCB, I wanted to ask:

• Has anyone here already done this conversion (for any system, not just CD-i), or seen one documented?

• Does anyone have photos, traces, or a schematic of the Roller Controller’s internal PCB showing the encoder/sensor pinout? I’ve found references to the LTE-302 (IR emitter) and LTR-301 (phototransistor) parts used inside, but no full wiring diagram.

• Any known quirks with this specific unit’s signal levels or wiring I should watch out for?