Casio PV-1000/Controller port pinout

The TJ-1 controllers used by Casio's PV-1000 and PV-2000 use a Mini-DIN-8.

Existing games expect the controllers to form a 4x4 button matrix, manually scanned by the software.

GPI2 ___|___    GND ---8/-O O O-\6--- GPO52 /        \ GPO55 ---5|-O   O   O-|3--- GPO53 \   |    /    GPI1 ---2]-O | O-[1--- n/c ---|---                |               GPO54

The actual mapping of which General Purpose Outputs and Inputs correspond to which button and thus which bits read from I/O port $FD has not yet been determined.