The Kenny McCormick Memorial

Atari 2600 Programming Page

Updated 11/3/97: Minor corrections. Watch for OYSTRON coming soon!

Tools | Games | Homebrew | Docs | Links | Misc | Mail

The Atari 2600 is one of the simplest video game systems ever invented, yet it is one of the most complicated for which to program. Even the simplest games have required programmers to write tight code to fit in the 4K of address space, fast code to account for many timing considerations, and smart code to squeeze as much as possible out of the primitive TIA chip. For this reason, very few new Atari 2600 games have come out despite the availability of the Supercharger and all of the development tools designed to work with it. Even the Vectrex has had five new games released in the past two years. Hopefully, this page will change all that.

• Programming Tools: Compilers, converters, disassemblers and emulators. For DOS, Amiga, Mac, and Linux.
• Disassembled Games: See some of your favorite Atari games as you've never seen them before.
• Homebrewed Games: New games and demos programmed by hobbyists in the last year or so.
• Technical Documents: Manuals and how-to files regarding the intricate details of the 2600's hardware.
• VCS Links: Mine isn't the only page out there with useful information.

Programming Tools

• StellaGraph 1.1 by Christopher James Pepin - Makes the task of designing playfield graphics that much more bearable. Visit the homepage. Requires version 4 of the VB runtime libraries, see readme file.
• Stella version 0.7, by Bradford W. Mott, et al. A faithful Atari emulator for many platforms. Originally developed for Linux, eventually ported to DOS, OS/2, Power Mac, Unix/X-Windows, and now Windows 95.
• PC Atari version 2.0b, by John Dullea. . Runs under DOS or Windows 95. Invaluable for those developing on slow machines, especially now that it's so much more compatible. This one even handles the Cosmic Ark starfield effect, as well as Pitfall II.
• DASM version 2.02 by Matt Dillon. Zip file. Compiles 6502 source code. Much of the code on this page is in DASM format. Use -f3 switch to compile standard .BIN files.
• Makewav version 3.1, by Bob Colbert. Zip file. Converts 2k, 4k, or 6k BIN files into WAV files that can be played into the Supercharger.
• DiStella by Bob Colbert. Zip file. Disassembles BIN files. Includes cycle counts, too. Find out what makes your favorite game tick.

• DASM version 2.02 by Matt Dillon. LHA file.
• Makewav version 3.1, by Bob Colbert. LHA file.

• Linux VCS package, contains DASM, Makewav, and DiStella executables for Linux. Executables ONLY, no source code or docs. Thanks to Greg Troutman for compiling these for everyone. Download the zipped file, and then visit the pages for Makewav, and DiStella.

Disassembled Games

• Combat Updated 2/26/97. Reverse-engineered by Nick Bensema. One of the first public-released reverse-engineering attempts. Compiles with DASM.
• Defender Updated 2/24/97. Far from even close to coherent, but it does compile.
• Adventure From VGR, almost every line of code is explained here. Strange format, hex numbers have & and there are no equates. But still a smashing job. He used these notes to write Indenture.
• Freeway Reverse-engineered by Bill Heineman, Very complete. Compiles on an Apple II; it's that old. :-)

Home-Brewed Projects

If you have any programs you would like added to this list, please mail me at nickb@primenet.com. PLEASE remember to do this because I usually won't put up anything unless I get explicit permission to put it up.

These games are in formats which may not be familiar to some users. Games in .BIN format can be run on emulators for play on your computer of choice, or converted into .WAV files by a program like Makewav. Both kinds of programs are available in the tools section. Games in .WAV format can be played on Atari systems equipped with Starpath Superchargers. Some games take advantage of the Supercharger's memory capabilities and are only available in .WAV format.

For your convenience, these games are now listed so that the newest entries are listed first, for your convenience.

Keep an eye out for OYSTRON by Piero Cavina - Currently up to version 2.9, and almost ready for release!

• RESCUE by Greg Troutman - There's this space station, you're supposed to dodge the asteroids so you can land and rescue the guys. Here's an off-site link to the game; it's updated quite often. I can't keep up with the updates, frankly, but the link will always give you the latest public version.
• INV by Erik K Mooney - This project was intended to become a more arcade-faithful version of Space Invaders. It has animated invaders, and almost-functional shields and two-player modes. The project is halted, for now, but released for the benefit of other programmers. Everything you need is in thie zip file
• Stell-A-Sketch by Bob Colbert - homepage - another Bob Colbert production. Makes extensive use of the Supercharger's RAM. The latest version allows use of driving controllers, the joystick, or mice from the Atari ST or Amiga. Wow.
• Tetris26 by Colin Hughes - 9-Jun-97 version, a tetris clone made as a programming exercise. Uses a 20-column display for top line, color playfield, blocks are slightly spaced, playfield is arcade-size (10 blocks wide). Read the source code to see how he did it. Download the zip file for everything you need. Freeware.
• Led Zeppelin Demo - version 0. As far as I know, this is the first Atari 2600 demo with sound. It sucks, though, because I haven't put in drums, and it doesn't follow proper VCS program flow; i.e. it doesn't draw a screen. Look for updates this summer by me, or sooner by other programmers. Source and binary are all available in this zip file.
• The Dark Mage by Greg Troutman - The first text adventure for the Atari 2600. Text routines are based on Stellar Track by Atari. The most current version of the program is available as zipped .WAVs that work on your Supercharger, and now in an 8K .BIN that works with emulators and on cartridges. Also, check out the original 4k version: zipped with source, .BIN only. Note: The source code compiles with DASM 2.12. Unfortunately, only 2.02 is available for DOS, so far.
• Okie Dokie by Bob Colbert - homepage, zipped archive, believed to be the first home-brewed VCS game since Edtris. Based loosely on games like Merlin and Lights-Out. The home page contains the source code, cartridge information and other information regarding this shining ray of hope to all VCS programmers.

Programming Documents

• Stella Programmer's Manual Detailed descriptions of most of the hardware of the Atari 2600.
• Stella Manual in Word for Windows Explains the Atari hardware with formatting and illustrations. If you know where to find the version in PDF format, please let me know.
• Supercharger Notes" by Christopher Salomon, 16-Jun-97. Notes concerning tape formats, Supercharger RAM, and bankswitching.
• Sound Frequency and Waveform Guide by Eckhard Stolberg, updated 22-Jun-97. This file contains, so far, the most complete information available on the 2600's sound hardware. This chart lists every distortion's approximate note value where applicable, and contains some extra technical information. Also see an earlier version done by Glenn Saunders in April.
• Guide to Cycle Counting Updated 4/3/97. My first programming document. The easy way to deal with a few of the timing issues of the 6502 and TIA.
• How to Draw a Playfield Updated 3/2/97. Covers concepts of program flow on an Atari 2600, as well as a complex look at a simple display routine. Compiles with DASM, so feel free to experiment with it; filter all the lines that begin with ';' to get a compact source listing.
• VCS.H - The one used in Dark Mage. The one I used to use sucks.
• How to Program the 2600 in BASIC :-)
• 6502 information... an off-site link to a file on the Wiretap archive.

VCS Programming Links

• Bob Colbert's Atari 2600 Homepage Contains information and tools for the Starpath Supercharger, allowing one to use it as an inexpensive development system. Also has some hardware information, such as how to build a 2600 multicart, and how to modify your Supercharger to run ALL of the 2k or 4k games available.
• Dan Boris' Atari tech page Highlights of this page include Boris' 6502 Processor Page which contains many files with information on the processor used in the Atari 2600. These files are especially useful for those who have no experience in 6502 assembly. Also, check out his section on 2600 development systems.
• Stella Mailing List Archives contains all of the brilliant ponderings of contributors to the programmers' mailing list administered by Glenn Saunders. Contains much information that is too specific, outdated, or incomplete to be included here. You may also subscribe to the list if you're interested in keeping up with current developments.

MIscellaneous

These links aren't entirely about VCS programming, but are related in some way and are most likely of interest to VCS programmers.

• Vectrex Development Pages The Vectrex shares much in common with the VCS, and is certainly just as unique.
  • Clay Cowgill's Page - get programming info here
  • John Dondzila's Page - get RAMcart instructions here
• Cyberpunks Project Page updated 9/10/97 - The FAQ is now HTML-ized. Multimedia coming soon. Cyberpunks brought us the Supercharger CD, and their latest project is a documentary about the 2600.
• Yoshi's NES Development page - Just like this page but not quite as many files; there are even fewer NES developers than there are VCS developers.
• NEScript - NEScript is intended to be a mid-level programming language for the Nintendo Entertainment System. It is currently in the design stages, and so far is very similar to C. The author hopes to have a compiler out in about two months. Such a thing is highly improbable for the VCS, so this is your best bet if you want to program a legacy video game system without learning assembly language.
• NES Software Development Information - Not really an organized information repository, but the story about how the author managed to create his own working home-brewed NES demo.

© 1997 Nick Bensema