Atari 7800

The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console officially released by the Atari Corporation in 1986.[3] It is almost fully backward-compatible with the Atari 2600, the first console to have backward compatibility without the use of additional modules. It was considered affordable at a price of US$140 (equivalent to $327 in 2019).

Atari 7800 ProSystem
Atari 7800 Logo.png
Atari 7800 System (American system with joystick controller)
Atari 7800 System (PAL system with Joypad controller)
Top: North American 7800
Bottom: European 7800
ManufacturerAtari, Inc.
Atari Corporation
TypeHome video game console
GenerationThird generation
Release dateUS: May 1986[1]
PAL: 1987
Introductory priceUS$140 (equivalent to $327 in 2019)
DiscontinuedJanuary 1, 1992[2]
MediaROM cartridge
CPUAtari SALLY 6502 ("6502C") clocked at 1.19-1.79MHz,
Memory4KB RAM, 4KB BIOS ROM, 48KB Cartridge ROM Space
Display160×240, 320×240 (160×288/320×288 if PAL), 25 on-screen colors out of possible 256
GraphicsMARIA custom chip @ 7.16 MHz
Atari 2600
PredecessorAtari 5200
SuccessorAtari XEGS

The 7800 has significantly improved graphics hardware over the 2600 but uses the same audio chip. It shipped with a different model of joystick from the 2600-standard CX40 and Pole Position II as the pack-in game. Most of the announced titles at launch were ports of 1981–83 arcade games.

The 1986 launch is sometimes referred to as a "re-release" or "relaunch" because the Atari 7800 had originally been announced on May 21, 1984, to replace Atari Inc.'s Atari 5200,[4][5] but a general release was shelved due to the sale of the company.[6]


Atari had been facing pressure from Coleco and its ColecoVision console, which supported graphics that more closely mirrored arcade games of the time than either the Atari 2600 or 5200. The Atari 5200 (released as a successor to the Atari 2600) was criticized for not being able to play 2600 games without an adapter.

The Atari 7800 ProSystem was the first console from Atari, Inc. designed by an outside company, General Computer Corporation (GCC). It was designed in 1983–1984 with an intended mass market rollout in June 1984, but was canceled shortly thereafter due to the sale of the company to Tramel Technology Ltd on July 2, 1984. The project was originally called the Atari 3600.[7]

With a background in creating arcade games such as Food Fight, GCC designed the new system with a graphics architecture similar to arcade machines of the time. Powering the system is a slightly customized 6502 processor, the Atari SALLY (sometimes described as a "6502C"),[8] running at 1.79 MHz. By some measures the 7800 is more powerful, and by others less, than Nintendo's 1983 NES.[9] It uses the 2600's Television Interface Adaptor chip, with the same restrictions, for generating two-channels of audio.


The 7800 was initially released in southern California in June 1984,[10] following an announcement on May 21, 1984, at the Summer Consumer Electronics Show.[4] Thirteen games were announced for the system's launch: Ms. Pac-Man, Pole Position II, Centipede, Joust, Dig Dug, Desert Falcon, Robotron: 2084, Galaga, Food Fight, Ballblazer, Rescue on Fractalus!, Track & Field, and Xevious.

On July 2, 1984, Warner Communications sold Atari's Consumer Division to Jack Tramiel.[11] All projects were halted during an initial evaluation period. Modern publications have often incorrectly asserted that Jack Tramiel mothballed the Atari 7800, feeling that video games were a past fad, and subsequently asserted that he dusted off the Atari 7800 once the Nintendo Entertainment System became successful. The reality was that a contractual issue arose in that GCC had not been paid for their development of the 7800. Warner and Tramiel battled back and forth over who was accountable, with Tramiel believing that the 7800 should have been covered as part of his acquisition deal. In May 1985, Tramiel relented and paid GCC the overdue payment. This led to additional negotiations regarding the initial launch titles that GCC had developed and then an effort to find someone to lead their new video game division, which was completed in November 1985.[12] The original production run of the Atari 7800 languished on warehouse shelves until it was re-introduced in January 1986 after negotiations with GCC concluded. The console was released nationwide in May 1986 for $79.95.[1][13] The console's launch was aided by a marketing campaign with a budget in the "low millions" according to Atari Corporation officials, which was substantially less than the $9 million dollars spent by competitor Sega, and the $16 million spent by competitor Nintendo.[14] This is likely attributed to Atari Corporations lack of finances early on, which had brought skepticism from insiders during the launch of the Atari ST.[15] Atari Corporation's launch of the Atari 7800 was different than the original plans under Warner, the keyboard and high score cartridge were canceled, the expansion port was removed from later production runs of the system and, in lieu of new titles, the system was launched with titles intended for the 7800's debut in 1984.[16]

By the end of 1986, Computer Entertainer claimed the Atari 7800 had sold 100,000 consoles in the United States,[1][17] less than the Master System's 125,000 and the NES's 1.1 million.[1] According to Atari, due to manufacturing problems, it only managed to produce and sell 100,000 units by 1986, including units that had been in a warehouse since 1984. A common complaint in 1986 was a lack of games, including a gap of months between new releases (Galaga's release in August was followed by Xevious in November).[17] By the end of 1986, the 7800 had 10 games, compared to Sega's 20 and Nintendo's 36. Nine of the NES games were third-party, whereas the 7800 and Master System had no third-party games.[1]


Atari's lineup for the 7800 emphasized high-quality versions of games from the golden age of arcade video games like Joust and Asteroids,[18] which at the time of the 1986 launch were four and seven years old, respectively.

Eleven titles were developed and sold by three third-party companies under their own labels for the 7800 (Absolute Entertainment, Activision, and Froggo) with the rest published by Atari. Most of the games from Atari were developed by outside companies under contract.[19]

Some NES titles were developed by companies who had licensed their title from a different arcade manufacturer. While the creator of the NES version would be restricted from making a competitive version of an NES game, the original arcade copyright holder was not precluded from licensing out rights for a home version of an arcade game to multiple systems. Through this loophole, Atari 7800 conversions of Mario Bros., Double Dragon, Commando, Rampage, Xenophobe, Ikari Warriors, and Kung-Fu Master were licensed and developed.[citation needed]


The Atari 7800 remained officially active in the United States between 1986 and 1991 and in Europe between 1989 and 1991. On January 1, 1992, Atari Corp. formally announced that production of the Atari 7800, the Atari 2600, the Atari 8-bit computer line, and the Atari XE Game System would cease. (It has since been discovered that Atari Corp. continued to develop games such as Toki for the Atari 7800 until all development was shut down in May 1993.[20]) By the time of the cancellation, Nintendo's NES dominated the North American market, controlling 80% while Atari Corp. controlled just 12%.[21]

Despite trailing the Nintendo Entertainment System in terms of the number of units sold, the 7800 was a profitable enterprise for Atari Corp., benefiting largely from Atari's name and the system's 2600 compatibility. Profits were strong owing to low investment in game development and marketing.[citation needed]

Retro Gamer magazine issue 132 reported that according to Atari UK Marketing Manager Darryl Still "it was very well stocked by European retail; although it never got the consumer traction that the 2600 did, I remember we used to sell a lot of units through mail order catalogues and in the less affluent areas".[22]

Technical specificationsEdit

Motherboard of an American 7800 with the RF shielding removed
European motherboard modified by Atari to output RGB though a SCART connector
  • CPU: Atari SALLY 6502 ("6502C")
  • RAM: 4 KB[8] (2 6116 2Kx8 RAM ICs)
  • ROM: built in 4 KB BIOS ROM, 48 KB Cartridge ROM space without bank switching
  • Graphics: MARIA custom chip
  • I/O: Joystick and console switch IO handled by 6532 RIOT and TIA
  • Ports
    • 2 joystick ports
    • cartridge port
    • expansion connector
    • power in
    • RF output
  • Sound: TIA as used in the 2600 for video and sound. In 7800 mode it is only used for sound.


Graphics are generated by the custom MARIA chip, which uses an approach common in contemporary arcade system boards[29] and is different from other second and third generation consoles. Instead of a limited number of hardware sprites, MARIA treats everything as a sprite described in a series of display lists. Each display list contains pointers to graphics data and color and positioning information.

MARIA supports a palette of 256 colors and graphics modes which are either 160 pixels wide or 320 pixels wide. While the 320 pixel modes theoretically enable the 7800 to create games at higher resolution than the 256 pixel wide graphics found in the Nintendo Entertainment System and Master System, the processing demands of MARIA result in most games using the 160 pixel mode.[citation needed]

Depending on various parameters, each individual sprite can use from 1 to 12 colors, with 3 colors (plus a 4th "transparency" color) being the most common. In this format, the sprite is referenced to one of 8 palettes, where each palette holds 3 assignable colors. There is also an assignable background color, which is visible wherever another object has not covered it up. In total the system can reference a 25-color palette on a scanline.[32]

The graphics resolution, color palette assignments, and background color can be adjusted in between scanlines. This technique is documented in the original 1983 Atari 3600 Software Guide.[32] This can be used to render high resolution text in one area of the screen, while displaying more colorful graphics at lower resolution in the gameplay area.


The 7800 uses the TIA chip for two channel audio, the same chip used in the 1977 Atari VCS, and the sound is of the same quality as that system. To compensate, GCC's engineers allowed games to include a POKEY audio chip in the cartridge. GCC originally planned to make a low-cost, high performance sound chip, GUMBY, which could also be placed in 7800 cartridges to enhance its sound capabilities further.[citation needed] This project was cancelled when Atari was sold to Jack Tramiel.

Only Ballblazer and Commando include POKEY hardware.

Lockout featuresEdit

Following the debate over Custer's Revenge, an Atari 2600 VCS title with adult themes, Atari had concerns over similar adult titles finding their way onto the 7800 and displaying adult content using the significantly improved graphics capabilities of the MARIA chip. To combat this, they included a digital signature protection method which prevented unauthorized 7800 games from being played on the system.

When a cartridge is inserted into the system, the 7800 BIOS generates a digital signature of the cartridge ROM and compares it to the signature stored on the cartridge. If a correct signature is on the cartridge, the console operates in 7800 mode, granting the game access to MARIA and other features. If a signature is not located, the 7800 remains in 2600 mode and MARIA is unavailable. All 7800 games released in North America had to be digitally signed by Atari. This digital signature code is not present in PAL 7800s, which use various heuristics to detect 2600 cartridges, due to export restrictions. The signing utility was found and released by Classic Gaming Expo in 2001.[33]

Backward compatibilityEdit

The Atari 7800 differs from the 2600 in several key areas. It features a full Atari SALLY 6502 processor whereas the 2600 VCS has a stripped-down 6507 processor running at a slower speed. It has additional RAM and the ability to access more cartridge data at one time than the 2600. The most substantial difference, however, is a graphics architecture which differs markedly from either the Atari 2600 VCS or Atari's 8-bit line of computers.

The 7800's compatibility with the Atari 2600 is made possible by including many of the same chips used in the Atari 2600. When operating in “2600” mode to play Atari 2600 titles, the 7800 uses a Television Interface Adapter (TIA) chip to generate graphics and sound. The processor is slowed to 1.19 MHz, enabling the 7800 to mirror the performance of the 2600's 6507 processor. RAM is limited to 128 bytes found in the RIOT and game data is accessed in 4K blocks.

When in “7800” mode (signified by the appearance of the full-screen Atari logo), the graphics are generated entirely by the MARIA graphics processing unit. All system RAM is available and game data is accessed in larger 48K blocks. The system's SALLY 6502 runs at its normal 1.79 MHz instead of the reduced speed of 2600 mode. The 2600 chips are used in 7800 mode to generate sound and to provide the interfaces to the controllers and console switches.

The Atari 7800 does not support backward compatibility for Atari 5200 games or accessories.

System revisionsEdit


  • Atari 3600, original model number
  • Atari CX-9000 Video Computer System


  • Atari CX7800, two joystick ports on lower front panel. Side expansion port for upgrades and add-ons. Bundled accessories included two CX24 Pro-Line joysticks, AC adapter, switchbox, RCA connecting cable, and Pole Position II cartridge.
  • Atari CX7800, second revision. Slightly revised motherboard, added an additional timing circuit. Expansion port connector removed from motherboard but is still etched. Shell has indentation of where expansion port was to be.
  • Atari CX7800, third revision. Same as above but with only a small blemish on the shell where the expansion port was.


The gamepad of later European Atari 7800s with the thumbstick screwed in

The Atari 7800 came bundled with the Atari Pro-Line Joystick, a two-button controller with a joystick for movement. The Pro-Line was originally developed for the 2600 and was advertised in 1983,[34] but delayed until Atari proceeded with the 7800. The right fire button only works as a separate fire button for certain 7800 games that utilize it; otherwise, it duplicates the left fire button, allowing either button to be used for 2600 games. While physically compatible, the 7800's controllers were incompatible with the Sega Master System, and Sega's controllers were unable to use the 7800's two-button mode.

In response to criticism over ergonomic issues in the 7800's Pro-Line controllers, Atari later released a joypad controller with the European 7800.[citation needed] It was similar in style to controllers found on Nintendo and Sega Systems. The joypad was not available in the United States.

There were few add-on peripherals for the 7800, though its backwards compatibility feature allowed it to use most Atari 2600 peripherals. The Atari XG-1 light gun, which came bundled with the Atari XEGS, was sold separately for other Atari systems and was compatible with the 7800. Atari released five 7800 light gun games: Alien Brigade, Barnyard Blaster, Crossbow, Meltdown, and Sentinel.

Canceled peripheralsEdit

After the acquisition of the Atari Consumer Division by Jack Tramiel in 1984, a number of planned peripherals for the system were canceled:

  • The High Score Cartridge was designed to save player high scores for up to 65 separate games.[citation needed] The cartridge was intended as a pass-through device (similar to the later Game Genie). Nine games were programmed with the feature but the cartridge was canceled before it was released.
  • The 7800 has an expansion port to allow for the addition of a planned computer keyboard and connection to laserdisc players and other peripherals. The expansion port was removed in the second and third revisions of the 7800.[35]
  • A dual joystick holder was designed for Robotron: 2084 and future games like Battlezone, but not produced.[36]

Software libraryEdit

Atari 7800 with Donkey Kong Junior cartridge

While the 7800 can actually play hundreds of titles due to its compatibility with the Atari 2600, there was limited third-party support for the 7800 and fewer than 100 titles were specifically designed for it.


Atari FlashbackEdit

In 2004, Atari (now owned by Infogrames) released the first Atari Flashback console. This system resembled a miniature Atari 7800 and joysticks and had 20 built in games (five 7800 and fifteen 2600 titles). While the unit sold well, it was controversial among Atari fans. Atari had given the engineering firm, Legacy Engineering, extremely limited development timelines. The firm was forced to build the Flashback using NES-On-A-Chip hardware instead of recreating the Atari 7800 hardware. As a result, the Flashback has been criticized for failing to properly replicate the actual Atari gaming experience.

Legacy Engineering was later commissioned to create another 7800 project that was subsequently cancelled after prototypes were made.[37]

Emulation and homebrewEdit

When emulators of 1980s video game consoles began to appear on home computers in the late 1990s, the Atari 7800 was one of the last to be emulated. The lack of awareness of the system, the lack of understanding of the hardware, and fears about the digital signature lockout initially caused concerns. Since that time, however, the 7800 has been emulated successfully and is now common on emulation sites. One such program is ProSystem, written in C/C++ for the Microsoft Windows operating system.[38] It uses the Windows API and DirectX to display what it emulates in both PAL and NTSC.

The digital signature long prevented homebrew games from being developed until the original encryption generating software was discovered. When the original digital signature generating software was turned over to the Atari community, development of new Atari 7800 titles began. In addition, the Atari community has slowly uncovered the original 7800 development tools and released them into the public domain. New tools, documentation, source code and utilities for development have since been created which has sponsored additional homebrew development. Several new commercial Atari 7800 titles such as Beef Drop, B*nQ, Pac-Man Collection, Combat 1990, Santa Simon, and Space War have been released.

Source codeEdit

The source code for 13 games, as well as the OS and development tools (for the Atari ST computer system) were discovered in a dumpster behind the Atari building in Sunnyvale, California.[39] Commented assembly language source code was made available for Centipede, Commando, Crossbow, Desert Falcon, Dig Dug, Food Fight, Galaga, Hat Trick, Joust, Ms. Pac-Man, Super Stunt Cycle, Robotron: 2084, and Xevious.[40]

See alsoEdit


  1. ^ a b c d e Computer Entertainer, February 1987, page 13
  2. ^ Patterson, Shane; Brett Elston. "Consoles of the '80s". GamesRadar. Retrieved 1 April 2011.
  3. ^ Top 25 Videogame Consoles of All Time: Atari 7800 is Number 17, IGN.
  4. ^ a b "Atari unveils advanced video game that is expandable to introductory computer" (Press release). Atari, Inc. 1984-05-21. Retrieved 2010-04-30.
  5. ^ "Atari Video Game Unit Introduced", New York Times
  6. ^ AtariAge: Atari 7800 History, AtariAge.
  7. ^ "The Atari 7800 ProSystem". Archived from the original on 2013-01-17.
  8. ^ a b c "When Pac Ruled the Earth". Electronic Gaming Monthly (62). EGM Media, LLC. September 1994. p. 18.
  9. ^ "7800 compared to the NES". Atari 7800 Programming.
  10. ^ Goldberg, Marty (2012). Atari, Inc. Carmel, NY: Syzygy Co. ISBN 978-0985597405.
  11. ^ [Retrogamer Magazine, Issue #78, pp 53.]
  12. ^ [Retrogamer Magazine, Issue #78, pp 57]
  13. ^ Semrad, Edward (1986-06-26). "Atari's "Jr Pac-Man" scores for looks, sound". The Milwaukee Journal.
  14. ^ [blob:], Detroit Press, August 15th, 1986
  15. ^ [1], San Francisco Examiner, Jan 07, 1985
  16. ^ Atari 7800 - History of Video Game Consoles Wiki Guide - IGN, retrieved 2019-01-23
  17. ^ a b Computer Entertainer, December 1986, page 8
  18. ^ Katz, Arnie; Kunkel, Bill; Worley, Joyce (August 1988). "Video Gaming World" (PDF). Computer Gaming World. No. 50. p. 47. Retrieved 17 April 2016.
  19. ^ Jung, Robert A. "The Atari Timeline". Landley. Retrieved 13 February 2017.
  20. ^ "TOKI FOR 7800: DISCOVERY ANNOUNCEMENT". Beta Phase Games. Retrieved 2018-04-18.
  21. ^ "COMPANY NEWS; Nintendo Suit by Atari Is Dismissed". The New York Times. May 16, 1992. Retrieved April 25, 2010.
  22. ^ "Atari 7800 Prosystem 30th Anniversary". Retro Gamer. Retrieved 18 August 2018.
  23. ^ "Atari 7800 - Game Console - Computing History". Retrieved 2020-02-19.
  24. ^ a b c [2]
  25. ^
  26. ^ "Archived copy". Archived from the original on 2014-06-28. Retrieved 2014-09-29.CS1 maint: archived copy as title (link)
  27. ^ "The Atari 7800 ProSystem". Archived from the original on 2003-06-24.
  28. ^ a b
  29. ^ a b c
  30. ^ Grand, Joe; Mitnick, Kevin D.; Russell, Ryan (2004-01-29). Hardware Hacking: Have Fun while Voiding your Warranty. Elsevier. p. 201. ISBN 978-0-08-047825-8.
  31. ^ "Atari C012294 POKEY". Retrieved 2019-12-05.
  32. ^ a b [3]
  33. ^ Boris, Dan. "The Encryption Issue". Atari 7800 Tech Page. Retrieved 2 October 2013.
  34. ^ "Catalog - Atari (CO21776-Rev. A)". AtariAge.
  35. ^ "Atari Compendium".
  36. ^
  37. ^ "Archived copy". Archived from the original on 2011-03-11. Retrieved 2010-12-22.CS1 maint: archived copy as title (link) Legacy 7800 remade
  38. ^ Kohler, Chris (2005-10-12). "Playing Classic Console Games". Retro Gaming Hacks. foreword by Al Lowe (1st ed.). Sebastopol, CA: O'Reilly Media. pp. 156–157. ISBN 0-596-00917-8.
  39. ^ AtariMuseum - Site News: June 11, 2009, retrieved July 3, 2009
  40. ^ "7800 Games & Development" at The Atari History Museum website, retrieved July 3, 2009

External linksEdit