I've been developing a concept that combines the hardware legacy of the original Macintosh with the flexibility of the Sega Genesis. The goal is to create a cartridge-based add-on for the Genesis that effectively transforms it into a Macintosh Plus clone while still allowing for normal Genesis game playback.
The project is called MacintoshX.
What is MacintoshX?
MacintoshX is a hybrid cartridge that contains its own 68010 CPU, memory, MMU, and framebuffer logic. The Genesis’s onboard 68000 CPU is electrically disabled via the cartridge interface (/HALT), and the cartridge-mounted 68010 takes over as the system’s CPU. The cartridge manages the transition between Macintosh and Genesis environments through clean bus arbitration and memory isolation, enabling both systems to operate independently but share the same processor.
Features:
The MacintoshX operates similarly to the Sega 32X or Power Base Converter, but instead of extending the Genesis into a newer (or older) generation of game hardware, it expands the system into a fully functioning compact Macintosh. Projects like the Plus Too have provided inspiration for simplifying the Macintosh hardware logic, making this idea more viable.
Why do this?
This project is born from a fascination with retrocomputing and the idea of pushing shared architecture to the limit. The 68010 is capable of handling both systems, and with proper arbitration, can switch between modes cleanly. By isolating the memory and peripherals for each environment, you can play Genesis games or run Macintosh software without the two interfering.
Project Status:
This will be an open hardware and open software community project. Collaboration is encouraged. Hardware developers, FPGA enthusiasts, 68K aficionados, and anyone with experience in bus arbitration or Macintosh internals are welcome to contribute.
Links:
GitHub Repository (including full README and):
https://github.com/twinec/MacintoshX
Thanks for reading, and I’m looking forward to feedback from the community.
Two systems. One CPU. Game like it's 1991. Compute like it's 1986.
Apologies for the AI-ness of this description, I thought about this with ChatGPT
The project is called MacintoshX.
What is MacintoshX?
MacintoshX is a hybrid cartridge that contains its own 68010 CPU, memory, MMU, and framebuffer logic. The Genesis’s onboard 68000 CPU is electrically disabled via the cartridge interface (/HALT), and the cartridge-mounted 68010 takes over as the system’s CPU. The cartridge manages the transition between Macintosh and Genesis environments through clean bus arbitration and memory isolation, enabling both systems to operate independently but share the same processor.
Features:
- Cartridge-form factor compatible with Genesis Model 1/2/3, Nomad, Sega CDX, and JVC X’Eye
- Uses a single 68010 CPU shared between Macintosh and Genesis environments
- On-cartridge ROM, SRAM, MMU logic, and framebuffer
- Passthrough slot to retain Genesis cartridge compatibility (for games or accessories)
- DB-19 floppy connector to support original Macintosh drives or the BMOW Floppy Emu
- VGA output at 640×480 resolution for a clean Macintosh display (letterboxed from 512×342)
- Power supplied by an onboard PicoPSU to generate necessary +12V and –5V rails
- FPGA or CPLD handles bus arbitration and memory mapping
- Compatible with future expansion and reversible—no permanent modification to the Genesis is required
The MacintoshX operates similarly to the Sega 32X or Power Base Converter, but instead of extending the Genesis into a newer (or older) generation of game hardware, it expands the system into a fully functioning compact Macintosh. Projects like the Plus Too have provided inspiration for simplifying the Macintosh hardware logic, making this idea more viable.
Why do this?
This project is born from a fascination with retrocomputing and the idea of pushing shared architecture to the limit. The 68010 is capable of handling both systems, and with proper arbitration, can switch between modes cleanly. By isolating the memory and peripherals for each environment, you can play Genesis games or run Macintosh software without the two interfering.
Project Status:
This will be an open hardware and open software community project. Collaboration is encouraged. Hardware developers, FPGA enthusiasts, 68K aficionados, and anyone with experience in bus arbitration or Macintosh internals are welcome to contribute.
Links:
GitHub Repository (including full README and):
https://github.com/twinec/MacintoshX
Thanks for reading, and I’m looking forward to feedback from the community.
Two systems. One CPU. Game like it's 1991. Compute like it's 1986.
Apologies for the AI-ness of this description, I thought about this with ChatGPT
? (it was only the Sega Genesis in the US).
.
