[Coco] The Coco3FPGA - Bringing the Color Computer 3 into the new Millenium!

Bill Pierce ooogalapasooo at aol.com
Tue Feb 7 17:01:30 EST 2017

 I know most everyone (but a few newcomers), at one point or another, have heard mentions of Gary Becker's Coco3FPGA project. He's had this project going for many years now, but in talking with others, I find very few who know just how far the Coco3FPGA has come. Well... it's come a long waaay babeeee!!

At this point in the development of the Coco3FPGA, I feel that if we had more people involved in the project.. testing, writing software, etc, that this project would move along much farther than it already has, and I'll be a witness, it's come a long way already.

I know there's a few on the list that already know what I'm talking about, but this message is for all the others who think the Coco3FPGA project is just in some "BETA" stage and not very usable.... because this is not true. Over the past few years, the Coco3FPGA has matured greatly and has become a VERY usable machine, to say the least.

What I would like to do, is list the current features of the Coco3FPGA so that the uninformed will know the facts, for the truth will set your Coco free!!

The Coco3FPGA runs on a Terasic De-1 (DE-2 is a WIP) and completely simulates (not emulates) a real 512k Coco 3 with about 90% compatibility to it's mentor. It's "almost" cycle accurate in that a few instructions are a slight bit faster than the original (WIP). There is now a "daughter board" which adds an RTC, WiFi, 2nd RS-232, 2x Coco joystick ports (yes, Coco joysticks!), and 4 megs of RAM. Here's the lowdown on all the features:

Coco3FPGA (Stock DE-1 without the Analog Board):
(Coco 3 Features)

Full 6809 Coco 3 on the DE-1 project board (VHDL at v4.1) 98% cycle accurate (0.89mhz & 1.78mhz) based on John Kent's (System09 6809 core) & Gary's GIME core.

512k of RAM (1 Meg with special memory mod)
Color BASIC, Extended Color BASIC, & Super Extended Color BASIC fully supported (unmodified)
1 bit (cass) & 6 bit (DAC) sound
All GIME features supported

4x Emulated Floppy drives (utilizing Drivewire, but invisible to the user. abo. 98% compatible).
1x Full RS-232 (DB-9) port. Configurable to DriveWire or RS-232 Pak
PS/2 Keyboard, fully mapped to the Coco keymap (RSDOS & OS9)
VGA Video output
Run NitrOS-9 L2 v3.3.0 (Coco3FPGA port boot disks available on the NitrOS-9 snapshot site)

(Extended Features, all accessable via software)

25mhz Turbo Mode!!!!!!

Direct single byte memory access to ALL memory above 64k (no need for mapping in 8k blocks) with single byte to 64k block memory copies (from anywhere to anywhere) and "auto-increment" read/write on all memory access including block copies.
8 meg OS-9 Ramdisk (does not use the Coco 3 memory) (could be adapted easily for RSDOS) (NitrOs-9 driver on Coco3FPGA NitrOS-9 boot disks)

4 Slot Multipak Interface Emulation
2 Meg of flashable ROM memory usable for 8k, 16k, 32k and up to 128k banks for ROM storage, all selectable for the MultiPak above.

Orchestra90 Stereo 8 bit sound with direct access to stereo 16 bit sound!!
Extended Graphics mode with 640x450 full screen graphics with up to 256 colors, giving the user a 106x56 full screen text in 256 colors!!! (no Os-9 driver yet, WIP)

Coco 1 & 2 Semi-Graphics modes supported (not available on a real Coco 3, only SG4 was supported)
Software "RTC" (not battery backed)
SD card HD emulation Read/Write (OS9 only, for now)
Full DriveWire4 support via the "Becker Port" via emulated Floppy Disk Controller for RSDOS and normal DW4 access in NitrOs-9.

Switch to toggle blanking the 2nd scanline for that "real Coco 3" look

Coco3FPGA Analog Board Features:
(All features available via software)

4 Megs of Coco 3 memory (5 meg with the DE-1 memory mod). All memory has the same "direct access" as above including block copying. NitrOS-9 uses up to 2 megs transparently. Accessing the upper 2 meg of the 4 meg is a WIP.

2x Standard Coco Joystick ports with standard resolution as well as 12 bit resolution.
2nd DB-9 serial port, which allows the user to switch the Analog board port and the DE-1 port between DriveWire and RS-232 Pak modes.
Battery backed RTC (NitrOS-9 driver on Coco3FPGA NitrOS-9 boot disks)

WiFi module (no driver yet)
8 GPIO header for more expansion

VHDL source code available for conversion/expansion to other developer boards

As you can see, the Coco3FPGA has matured nicely :-)

We have a Yahoo Group page where you can find out about getting used DE-1s as well as the Analog Board (designed by Gary Becker and built by Ed Snider) and keep up with all the new developments and features (which seem to keep coming :-)
We keep ongoing conversations on various aspects of the Coco3FPGA as well as discussing software development. There's currently 370 members and many who have working Coco3FPGAs.

The Yahho Group site is here:


Come join in on the FUN!!

The Coco3FPGA - Bringing the Color Computer 3 into the new Millenium!!

Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull


My Music from the Tandy/Radio Shack Color Computer 2 & 3
Co-Contributor, Co-Editor for CocoPedia
Global Moderator for TRS-80/Tandy Color Computer Forums

E-Mail: ooogalapasooo at aol.com

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