The MiniITX Retro System

There are hundreds of modern, retrocomputing projects out there that put ancient CPUs and chips in a modern context. The Neon816 from [Lenore] is perhaps one of the most impressive projects like this we’ve seen. It’s a classic system in a modern form factor, with modern video output, mashed together into a MiniITX motherboard.

The powerhouse of this computer is the Western Design Center W65C816 CPU. This is the second generation of the venerable 6502 CPU, the same chip found in everything from the Commodore 64 to the Apple II to the Nintendo Entertainment System. The 65816 is a 6502 at start-up until you flip a bit in a register, at which time the signalling on the address bus becomes much weirder. We’ve seen some single board computers based on the 65816 before and The 8-Bit Guy has a few ideas to build a computer around this CPU, but for the foreseeable future work on that will be trapped in development hell.

Of note, the Neon816 will feature DVI output (I guess technically you can just run the analog signals through the connector), a PS/2 Joystick input, two Atari / Sega joystick ports, MIDI in and out, a PC-style floppy disc connector, and a Commodore serial bus. It’s a hodge-podge of classic retrotainment, all in a single MiniITX motherboard.

The key other feature of the Neon816 is an FPGA, specifically a Lattice XP2 8000 LUT chip that is used for video and audio. This is combined with 1MB of main RAM (looks like a simple SRAM) and 128k of Flash storage for the ROM. There’s also an SD card in there for storage.

Right now, [Lenore] is populating the first prototype board, and we can’t wait to see some video generated with this impressive little system.

12 thoughts on “The MiniITX Retro System

  1. I don’t know how or why you would consider the 8BG’s project “trapped in development hell” when it just became an idea and they’re at the point of brainstorming what parts to put on the board, among other things. The project basically just began. This sounds like nothing more than an attempt to bash someone else’s project in favor of this one, and that’s a pretty disgusting thing to do in such a niche community, imo.

    1. Yah. I believe this is the same pro cr he had mentioned in a vlog that he was considering, and working with the developer on, but for various creasons decided to move in different direction.
      Main technical reasons seemed to be form factor and that FPGA. Both of which put it over the cost edge. I got the feeling though there were other (unspoken) issues(?)

      Anyway I’d have to agree with 8BG. I mean no sound it would be a niceachine to play with, and in a modern, tight case, wonderful.

      But I’ll never use midi.
      I don’t have C= drives (just the 1541 raspberry pi emulator).
      Doubt I’d have any use for a floppy disk either.
      With an FPGA, might as well build any CPU / architecture you want. And canbeven do decide at boot.
      So then how does it differentiate from all the other modern fpga retro toys?

      I’d rather have all those options as modular expansion. A minimum viable retro board in my opinion just needs CPU, RAM, easily flashable ROM, SD card file system, and some form of AV out (rgb or HDMI, but even composite would be fine). Plus the expected keyboard / game ports.

    2. Not really, Leonor is engaged with the CX16 project, she just seems to have formed her own project but not with any malice on either side. She’s jumped ahead with her board but, while we should all wish her the best, it remains to be seen what her solo development velocity will be over time.

  2. Sounds like its custom build for the 8bit guy (who else would need midi-ports)

    If the Lattice is used for both audio and video, why not mux in the digital audio and generate a hdmi signal?
    and by using a passive dvi to hdmi adapter no hardware changes are needed.

    1. The reason for not adding HDMI is legal – yay patents. The DVI is electrically compatible, though.

      Unlike what the article above suggests, the DVI is DVI-D (digital), and it’s being generated with a dedicated serializer IC.

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