How to Build a Matchbox CoCo

The Matchbox CoCo is a Do It Yourself CoCo 3 clone that may or may not be offered by third parties fully assembled or by snap-together components.  This is not a Tandy or Radio Shack product, but you are welcome to customize your own system with Tandy or Radio Shack logos for cosmetic purposes.

Before you build this awesome all-hardware CoCo clone, let’s get a grand picture of things…

CoCo Clones Quick Reference

Some notable features

• The most accurate and capable all-hardware Tandy Color Computer 3 clone available.
• Very compact, cool running temperature
• Employs Greg Miller’s cycle-perfect 6809 core with .89, 1.79, 3.58, 7.16 Mhz rates.
• 1MB of RAM
• VGA port
• 512 colors
• Up to 640×480 resolution
• Up to 80×60 full color text
• Double height of any graphics/text mode
• HQ stereo sound jack for all audio generated by the system, 8 to 12 bits of precision per speaker.
• PS/2 keyboard and mouse ports
• SD card virtual disks/drives are also mapped to the FDC for high compatibility with floppy-based software.
• Cassette deck support
• Two dual-button joysticks
• Smart hi-res joystick/mouse circuit lets you run ColorMax Deluxe, CoCoMax III, gshell, etc. using your PS/2 mouse without having to toggle any switches.
• A/V digitizing support
• 40-bit fixed-point FPU
• Halt / no-halt GPU draws super fast lines, boxes, filled boxes, memory copies and memory fills.
• WIFI and bluetooth serial capable.
• CoCoNet bluetooth disk drives from DOS or OS-9.
• Reprogram the 8266-01 WIFI module using the Arduino IDE and other flashing utilities, over bluetooth!
• Runs OS-9/NitrOS-9 and Sock Master demos like a boss.

Summary of the main parts

• Terasic DE0-Nano FPGA board (Terasic) (Digi-Key)
  • What does the Terasic DE0-Nano do? It has chip real estate space that we will program to become a 6809 CPU, GIME, 6821 PIA, 6551 ACIA, AY-3-8910, and much more!
  •  Where can I get a Terasic DE0-Nano? From the Terasic web site, Amazon, ebay, and many other sellers, with Terasic being the cheapest source for a brand new unit.
• NanoMate upper daughter board for the DE0-Nano
  • What does the NanoMate board do? It adds VGA, SRAM, PS/2, audio, WIFI, Bluetooth, SD card to the DE0-Nano!
  • Where can I get most or all of the required components for the NanoMate board? Jameco, Digikey, are just a few places you can round up many of these items in one shipment.  Amazon and ebay are great places to find many of the optional and Arduino type components for cheap!
• NanoLog lower daughter board for the DE0-Nano
  • What does the Nanolog board do? It adds two dual-button joystick support and audio/video digitizing to the DE0-Nano.
• Plastic case
• PS/2 keyboard
• PS/2 mouse (if you don’t have a real CoCo joystick)
• VGA monitor or VGA-capable TV
• 1/8″ male to male stereo audio cable for amp or TV input
• FAT32 SD card with your favorite CoCo .dsk images and OS-9 images.
• DE0-Nano JIC Configuration File (Matchbox CoCo 3/4 core)

A few words about this project

To get up to speed on this new CoCo before you decide to build one or buy a pre-assembled kit from somebody in the CoCo community, first visit the Matchbox CoCo facebook group to see actual videos, snapshots, and discussions about this awesome CoCo clone that was started on July 4, 2015.

No, this CoCo model is not “smoke and mirrors” and it’s certainly not vapor ware or vapor hardware but more importantly much thought has been put into how this computer will be adopted by people in the CoCo community who want an alternative system for whatever reason they need.  Components have been chosen based on the endless supply of them so that no component will just suddenly “vanish” from the web after somebody does a huge buy-in, etc.  Any component that “dries up” suddenly like the 4D Systems uDrive module did or the EB301 bluetooth that were used in past products of mine have been secured. If something truly dries up and can’t be found (not a chance) I will simply release a new PCB that fits another brand of the required component such as SRAM, PS/2 connectors, audio jack, and VGA jack, etc.

I also want to re-introduce myself.  My name is Roger Taylor and I was studying digital logic and circuits as far back as 12 years old.  For some unknown reasons I was also writing programs in notebooks before I even owned my first home computer.  Some know me as a software guy.  None know me as a hardware guy.  You might even say that this new CoCo clone sort of “created itself”.  “It” knew it had to be done, and the original flashing LEDs of a simple 6809 CPU with 4K of RAM with no video “reached out to me” and said “I need more gates”.  “Give me video or give me death.”  “Hey man, 1MB, please?”  About, oh, 2 years later, the system has evolved into a full CoCo 3 clone that runs OS-9 like a boss and even runs Sock Master’s demos like a champ.  This project has been very fun yet extremely demanding.  This thing just didn’t happen out of thin air.  Family vacations were sacrificed and much soul has been put into this system on a daily basis. I’ve put all of my knowledge of digital design and programming into this system but I’m still learning new things as I go which is also important — always keep learning.  Never let others discourage you on something you love doing.  Just do it and knock their socks off.

Programming the DE0-Nano to become the Matchbox CoCo

The core IP for the Matchbox CoCo clone is available at Patreon.

Either you or somebody else will have to program your DE0-Nano board once or each time an upgrade to the CoCo system is released online.  To program the Nano yourself, you’ll need a copy of the free/lite Quartus II software and a Windows PC with a USB port.  Links to people who can provide a pre-programmed DE0-Nano or program yours for you will be provided over time on this site or you can ask around in the Matchbox CoCo facebook group.

You might ask, what about ROM paks and my Speech/Sound cartridge, hard drive controller, etc?  No cartridges are used or required.  For example, the SDC supports 1793 FDC mode and large hard drive images alike, and the Orchestra-90CC is also built into this system.  Need I say more? This will be an all-in-one solution to the best of my ability, and if I may say so, the idea is going Very Well.

By the way, this FPGA-based CoCo system uses what some people call an “FPGA development kit” with one giant “gotcha” catch…  the DE0-Nano FPGA kit is just a small board with headers with a plastic dust cover mounted to the top which when easily removed using 4 screws takes away the whole “kit” look.  Really, you’d be hard pressed to spend money developing anything close to the power of this small board that can work in harmony with a daughter board to do almost anything imaginable with digital signals. So, this system is far from being the fpgacoco3 project which requires a large and more expensive DE1 FPGA *Kit* and an analog board and possibly even an SRAM replacement (Scooby Doo says ughhh?)  but ours is just as powerful, so… please read on!

Matchbox CoCo case

After you assemble your Matchbox CoCo rig, you’ll want to protect it with the official Matchbox CoCo case.  Based on the “snappy boots” design the CoCo clone slides right in and gets snapped in snug and safe.  Buy one today.

The following people and others have contributed significant information or resources to this project:

• Bill Nobel (NitrOS-9 support: 80×28, 80×30, 80×48, 80×50, 80×56, 80×60 text mode drivers, GrfDrv, Turbo/80×60 REL module, lcdmode, mount, and more).
• Erik Gavriluk (donated an extra new Terasic DE0-Nano for lab work).
• Greg Miller (cycle-accurate 6809 CPU core, first of it’s kind!)
• Allen Huffman (CoCoFEST demonstrations, $ donations)
• Mike Craig (3-D renderings and printed case design)
• John Strong (3-D case)
• Kind donations and support from
  • James Jones (winner of the 2017 Christmas Cyclone drawing)
  • Richard Hawk
  • Steve Batson
  • Scott Brooker
  • Daniel Loyle
  • Arthur Kalwhite
  • John Robbs
  • Justin Thomas
  • Scott Wendt
  • Craig Madsen
  • Richard Ivey
  • Luciano Scharf
  • Norman Davie
  • James Ross
  • Mark Kohler
  • Ron Klein
  • Erik Gavriluk
  • Greg Miller
  • Don’t see your name?  Let me know and I’ll get you added.