A 65c816-based MiniITX motherboard.

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lenore-byron has 7 orders / 0 reviews
Ships from United States of America
This project is about the design of an 8-bit/16-bit nostalgia motherboard using currently in-production parts, and designed to interface primarily with modern peripherals.

Features based on modern peripherals:
- 2 Atari or Sega-style joystick ports. Should work with 6-button Genesis controllers, and many compatible controllers are currently in production.
- DVI-D output and HD-Audio-pinout case audio connections for modern systems.
- PC-style floppy drive controller.
- ATX power connector, including support for soft power.
- SD card connector.
- PS/2 keyboard input

Also some retro and general fun:
- Commodore serial bus.
- MIDI in and out.
- GPIO header for user IO.

It's specifications:
- Western Design Center W65c816S fully static 6502-compatible 16-bit CPU.
- 1MB of main system ram and an additional 512k of video RAM.
- 128k of Flash for system ROM image.
- Lattice XP2 8000LUT FPGA for video and audio generation.

I'm aiming for a blend of 8-bit and 16-bit generation hardware and capabilities, but with a decidedly 8-bit themed user experience.  The most important thing is the immediacy of 8-bit style computers, without complicated boot sequences, memory protection, or multi-user, multitasking operating systems.  It should be easy to just power it up and start poking ports to see what happens.

That said, I plan to add some capabilities normally seen in the 16-bit generation, including some inspiration from the Amiga, Genesis, and SNES.

The current status of the project: the hardware design is complete and all parts are in house.  Currently working on initial build and test.

A Facebook group exists for those who like that sort of thing:


Neon firmware loader for Linux.

x-gtar - 14.28 kB - 12/01/2019 at 15:07



Neon816 Programmer's Reference Manual (Version 0.1)

Adobe Portable Document Format - 156.59 kB - 11/20/2019 at 20:04


  • A couple revisions and a lot of work later.

    Lenore Byron10/21/2019 at 08:30 0 comments

    It now boots into a Forth OS and is interactive over a serial connection.  HP serial protocol analyzer is being used as a dumb terminal here.

  • On to Rev2 and manufacturing plan.

    Lenore Byron06/13/2019 at 14:02 0 comments

    This is what the finished Rev1 looks like.  There were some issues around the joystick port, and I've added a couple features for Rev2.  I'm working on that now.

  • Video Generation!

    Lenore Byron04/07/2019 at 23:07 0 comments

    So the video generation is working.  DVI-D through a passive HDMI converter, to an HDMI small form factor monitor.  Also, the CPU is running and executing code, and I used it to configure the DVI encoder via I2C.

  • Building and Testing

    Lenore Byron03/23/2019 at 12:40 0 comments

    I'm working on building up the board.  The FPGA is programming nicely, I've got the UART working, and I'm building up all the missing parts.  Still waiting on a few connectors, and adding things as I test.

  • Oops decoupling.

    Lenore Byron03/21/2019 at 11:55 0 comments

    Had a bit of an issue sending a bitstream to the FPGA.  After some bug hunting, I realized it was just an electrical noise issue.  Added a bunch more decoupling capacitors and now I can program it.

    I'll fix that in the next revision.

  • It's alive!

    Lenore Byron03/20/2019 at 05:48 0 comments

    I built up the power supply sections, and they're working.  Then I tried to read the ID code from the FPGA - success!

    I guess my first attempt at BGA soldering worked out after all.

  • Reflowed my first BGA!

    Lenore Byron03/17/2019 at 21:14 0 comments

    I got my reflow oven working and attached my first BGA!

    I didn't know how well it would work, so I only attached the 2 parts I absolutely needed reflow for.  I'll hand solder things on as I need them for this board.

  • Boards arrived!

    Lenore Byron03/11/2019 at 18:08 0 comments

    The boards are here!  Now I need to figure out how I'm supposed to attach a BGA.

    Also I need to dig out a proper camera and take a decent picture.

View all 8 project logs

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Carol Driscoll wrote 12/12/2019 at 14:55 point

I was in dire need of A 65c816-based MiniITX motherboard but price of your similar product is very high that I am unable to purchase it. You have kept some of the very exciting features in this product but it is very expensive. Spotify Premium is the best for me to indulge in such projects and share with others safely.

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rwbaskette wrote 06/08/2019 at 20:04 point

This is almost a ITX Apple IIgs!

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bobcousins42 wrote 03/17/2019 at 15:42 point

I think you've got a good blend of old+new there, looking forward to seeing how you get on.

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Jonathan 'theJPster' Pallant wrote 03/17/2019 at 10:42 point

I'm making something similar but with an ARM Cortex M4. Where did you get the double stacked PS/2 and DE9 headers? They look ace! Couldn't find anything good on the usual catalog retailers but the singles take so much board space. PS: Have you considered pin headers to hook up an old PC expansion plates with 2x Serial / 1x Parallel ports?

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Lenore Byron wrote 03/17/2019 at 11:41 point

I think Digikey has the DE9, but I got them from Aliexpress.  Or "will get", the lead times are pretty long and I don't have them yet.

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cuvtixo wrote 03/17/2019 at 06:42 point

I'm not really clear on how much you are thinking of this as a gaming device. Are you thinking of also providing a Basic language (or 2 or more?) so we can relive early programming experiences? Personally, though, I mostly remember a lot of frustration and failures to actually make anything but the simplest programs to work, so maybe not. My nostalgia is for the Apple IIe, but I don't know if your thinking of anything in that direction, though.

  Are you sure? yes | no

Lenore Byron wrote 03/17/2019 at 10:14 point

That depends on if anyone likes it!  For the moment I'm focused on the hardware and digital design, but a few people are looking at software already.

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Lenore Byron wrote 03/11/2019 at 22:25 point

My old project was restored by the admins.  I'd spent a bit more time on the description the first time around, so I'm making some edits here before removing the old one.

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Ekkehard Morgenstern wrote 03/11/2019 at 18:20 point

Test comment! :) 

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Dan Maloney wrote 03/11/2019 at 16:30 point

Looks like it's sticking around so far. And good thing - looking forward to more details.

  Are you sure? yes | no

Lenore Byron wrote 03/11/2019 at 17:20 point

I'll be posting more details soon.  The boards are currently being delivered to my workshop today, and most of the parts have already arrived.

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Lenore Byron wrote 03/11/2019 at 15:27 point

This is a repost, because the previous project just vanished without a trace.  Hopefully this one stays?

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