The Dragon 32/64 Computers

• Introduction
• Software
• Documentation
• Links
• Pictures

Introduction

The Dragon is an 8-bit personal computer based upon the Motorola MC6809E microprocessor. Made in Wales by Dragon Data Ltd., two variants were sold in the UK: the Dragon 32 (basic version, 32K RAM) and the Dragon 64 (64K RAM, serial port, other very minor differences). The on-board ROM contains a version of Microsoft Extended Colour BASIC, but more advanced operating systems like OS-9 and FLEX are available.

An NTSC version of the Dragon 64 was released in the USA as the Tano Dragon, and Eurohard repackaged it in Spain as the Dragon 200.

David Linsley has written a comprehensive history, available here.

Software

Available for download from this site:

XRoar

A free, cross-platform emulator of Dragon 32/64, Tano Dragon and Tandy CoCo 1/2.

• XRoar home page.

asm6809.pl

A 6809 macro assembler written in Perl. Quite good at generating efficient output.

• asm6809.pl Perl script v0.7.
• Usage guide.

6809dasm.pl

A 6809 disassembler written in Perl. The aim is to always produce code that can be reassembled by "a09".

• 6809dasm.pl Perl script.
• Usage guide.

PD Dragon 1 & 2

The two Dragonfire PD disks. There are a couple of little adventure games in there (probably by Robin Hemmings). Most interesting to me was "1770.BAS" (by M. Edwards) which allowed you to read BBC Micro disks.

• Archive containing both virtual disks: pd_dragon.zip (zip 110K).

The rest of these were written a long time ago and are included here more for historical purposes than because they're still useful:

DragonDOS disk reading tools

PC/MS-DOS tools written in Turbo C for reading DragonDOS disks. Includes tools to translate disk files into CAS files. Unfortunately, there is little documentation available, and I seem to remember the drive being hard-coded. Like most equivalent software, won't work in this day and age unless you have a drive controller that can handle SD/DD disks (sadly rare).

• Binary: pcdbin.tar.gz (tar.gz 15K) or pcdbin.zip (zip 24K).
• Source: pcdsrc.tar.gz (tar.gz 3.4K) or pcdsrc.zip (zip 6.7K).

FBACK2

A Dragon 64 tool to use the maximum possible memory for copying disks. Works very much like Graham Kinns' FASTBACK, but is relocatable so you don't have to lose current work.

• fback2.tar.gz (tar.gz 2.6K) or fback2.zip (zip 2.9K).

Miscellaneous

• 64K.CAS, standard ROM->RAM copy code.
• ALPHA.CAS, the VDG character set (originally obtained, I think, from Graham Kinns).
• HIRES.CAS, a hi-res screen driver that locates both the screen and the program code in high-RAM.
• VORDY.CAS and VBIN.CAS, the BASIC and binary sections of a small text editor that runs under HIRES.

• progs.tar.gz (tar.gz 5.0K) or progs.zip (zip 5.6K).

Documentation

• Hardware details - how the Dragon is put together.

Some that I wrote as a very young person (so please forgive the terrible writing style):

• Dragon video modes: a partial description of some of the results of SAM-VDG interactions better described in the hardware details page.
• Illegal 6809 Op-codes: an article written for Dragon Update, mostly about the "illegal" uses of the TFR and EXG instructions.

From other sources:

• 6809 Pinout and instruction set (local copy of a document by Jonathan Bowen).
• Technical information on the 6309 (local copy of a document by Chet Simpson and Alan DeKok).
• Fitting a 6309 (local copy of a document by Chris Burke).

Note: The 6309 is a version of the 6809 created by Hitachi, and includes more instructions, extra registers and a native, faster, execution mode.

Links

Other sites about the Dragon:

• The Dragon Archive. Including documentation, discussion forums and software downloads.
• Dragon Data Archive: lots of historical information about the company and pictures of hardware.
• Jon Bird has some good stuff on OS-9 and interesting hardware modifications.
• Paul Burgin's Dragon page, including:
  • The T3 and PC-Dragon emulators.
  • Description Of The Motorola 6809 Instruction Set.
  • Description of the Dragon Keyboard And Video Hardware.
• Graham Kinns's Dragon page, with lots of useful information files.
• Dragon Update on-line! A selection of newsletters converted to HTML.
• Dragnet Dragon Users Support Pages. Lots of info on the (now sadly defunct) NDUG.

And less directly Dragon-related:

• The Tandy Color Computer SuperSite. Versions 1 & 2 of the CoCo were very compatible with the Dragon, and although this site focusses quite strongly on the CoCo 3, there's still a lot of relevant information. Includes discussion forums and web-based chat area.
• L. Curtis Boyle's CoCo 1/2/3 web pages. Containing a fairly comprehensive (and still regularly updated) list of CoCo games, many of which were also released for the Dragon.
• MESS, the "Multiple Emulator Super System" - emulates a variety of old computer hardware, Dragon included. SDLMESS might be more appropriate, depending on your system.
• 6809 Emulation Page - lots and lots of information.
• Bill Yakowenko's CoCo stuff.

Updated 18 Apr 2008