Special controller only used in The Irritating Maze cabs.
Works the same way as an upside-down mechanical mouse. Uses two optical encoders for X and Y movement, handled by the SIT board.
A special system ROM is used (236-bios.sp1).
The counter values are read from REG_P1CNT:
- The X counter value when bit 0 of REG_POUTPUT is 0.
- The Y counter value when bit 0 of REG_POUTPUT is 1.
Speed and direction are computed from the counter deltas.