Sega Genesis
The Genesis — the Mega Drive outside North America — takes cartridges from your
roms/mega_drive folder. It is also the console Sega bolted the most hardware onto, and
both of its add-ons are real objects here.
They stack in opposite directions, which is what makes the full tower possible:
| Unit | Where it goes | Its media |
|---|---|---|
| 32X | Into the cartridge slot, with its own slot on top | roms/sega_32x |
| Sega CD | Underneath — the console stands on it | roms/sega_cd |
See expansion hardware for how a stack goes together.
The 32X
Section titled “The 32X”The 32X goes into the cartridge slot like a game, and has a cartridge slot of its own on top — it is the only Sega expansion here that a game cartridge goes into rather than past. Put a 32X cartridge in that upper slot.
A Genesis with a 32X on it is a different machine, and RetroXR switches to picodrive, which is both halves at once. Take the 32X off and the console goes back to its usual core.
The Sega CD
Section titled “The Sega CD”The Sega CD is a base the console stands on, and it loads from a tray — press the unit’s own eject button, put a disc in, close it.
On a Sega CD title the disc is the game and the console’s cartridge slot stays empty. The core is genesis_plus_gx.
The Power Base Converter
Section titled “The Power Base Converter”New in v0.6.0: the adapter that goes into the cartridge slot and lets a Genesis play Master System games. Put it in, put a Master System cartridge into it, and RetroXR switches to genesis_plus_gx, which is both machines.
Master System hardware has one add-on of its own here too — the FM Sound Unit, which attaches to a Master System and gets it the expanded soundtrack a number of Japanese releases shipped with. Like the Power Base Converter it sets the core options for you.
The Tower of Power
Section titled “The Tower of Power”Both at once: the Sega CD on the bottom, the Genesis standing on it, the 32X in the console’s slot. Sega never sold it as one product and it was famously precarious in real life — here it simply stacks.
RetroXR treats the full tower as its own machine rather than as two add-ons that happen to be present. It runs on picodrive, and the disc is still what boots — the tower exists so that a Sega CD game can use the 32X’s extra hardware, so the CD remains the thing being played.