The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console released by Atari Corporation in May 1986 as the replacement for the Atari 2600 and Atari 5200. It can play most games made for the Atari 2600, which made it the first console with backward compatibility. It came with a two-button controller instead of the Atari CX40 joystick used with the 2600, and included the game Pole Position II as a free gift with purchase. The European version of the console used a gamepad instead of a joystick. Many early games for the 7800 were versions of arcade games released between 1981 and 1983. Later games for the system had styles similar to those found on other consoles from the late 1980s, such as Scrapyard Dog and Midnight Mutants.

The 7800 was designed by General Computer Corporation. It has special graphics hardware similar to early 1980s arcade games and improved upon Atari’s earlier consoles. A special chip called the Television Interface Adaptor, first used in the Atari VCS in 1977, was included in the 7800 to allow compatibility with older games and to create two-channel audio for games. To avoid the problems that led to the video game crash of 1983, all cartridges for the 7800 had to be approved by Atari before being released.

The Atari 7800 and its first games were announced by Atari, Inc. on May 21, 1984. However, the release was delayed after Atari was purchased by Jack Tramiel, who rebranded the company as Atari Corporation. Support for the 7800, along with the 2600 and Atari 8-bit computers, ended on January 1, 1992.

History

The Atari 7800 ProSystem was the first console from Atari, Inc. created by an outside company called General Computer Corporation. It was developed between 1983 and 1984 with plans to release it to the public in June 1984. However, the project was canceled after Atari was sold to Tramel Technology Ltd on July 2, 1984. The system was originally named the Atari 3600.

General Computer Corporation, which had experience making arcade games like Food Fight, designed the 7800 with a graphics system similar to arcade machines from that time. The console used a modified 6502 processor called the Atari SALLY, which ran at 1.79 MHz. Compared to the 1983 Nintendo Entertainment System, the 7800 had both stronger and weaker features in some areas. It used the same Television Interface Adaptor chip as the Atari 2600, which limited audio to two channels. However, some games used a cartridge port to add extra sound through a sound chip in the cartridge.

The 7800 was announced on May 21, 1984. Thirteen games were planned for its launch, including Ms. Pac-Man, Centipede, Joust, Dig Dug, Galaga, and Food Fight. It was a major improvement over the Atari 2600 and Atari 5200.

On July 2, 1984, Warner Communications sold Atari’s Consumer Division to Jack Tramiel. All projects were paused during an evaluation period. General Computer Corporation was not paid for its work on the 7800, and Warner and Tramiel argued over who was responsible. In May 1985, Tramiel agreed to pay GCC. This led to further discussions about the games GCC had developed and efforts to hire a leader for Atari’s new video game division, which was completed in November 1985. The original batch of Atari 7800 consoles remained in storage until January 1986.

The console was released nationwide in May 1986 for $79.95, with games originally planned for its 1984 debut. Atari’s marketing campaign had a budget in the "low millions," which was much less than Sega’s $9 million and Nintendo’s $16 million. Plans for a keyboard and high score cartridge were canceled. The 7800 fixed many issues with the Atari 5200, such as a smaller size, built-in backward compatibility, and better controller design.

In February 1987, Computer Entertainer reported that 100,000 Atari 7800 consoles had been sold in the United States, including those stored since 1984. This number was lower than Sega’s Master System (125,000) and Nintendo’s NES (1.1 million). Games were released slowly: Galaga in August 1986 and Xevious in November 1986. By the end of 1986, the 7800 had 10 games, compared to Sega’s 20 and Nintendo’s 36. Atari sold over 1 million 7800 consoles by June 1988.

The Atari 7800 was released in the UK in September 1989 for £69.95, with two joypad controllers included.

On January 1, 1992, Atari Corporation announced the end of production and support for the 7800, 2600, and the 8-bit computer family, including the Atari XEGS. At least one game, an unreleased version of Toki, was still being worked on after this date. In Europe, the last Atari 7800 consoles were sold until summer or fall of 1995.

According to Atari UK Marketing Manager Darryl Still, as reported in Retro Gamer issue 132, the 7800 was well-stocked in European stores. Although it did not achieve the same popularity as the Atari 2600, it sold many units through mail-order catalogs and in areas with lower incomes.

Technical specifications

• CPU: The Atari 7800 uses a custom version of the 6502 chip called SALLY. It runs at 1.79 MHz (NTSC) or 1.77 MHz (PAL), but slows to 1.19 MHz (NTSC) or 1.18 MHz (PAL) when accessing the Television Interface Adaptor or 6532 RAM-I/O-Timer chips. Unlike a standard 6502, SALLY can be paused using a single pin to allow other devices to control the bus. Atari sometimes called it "6502C," but it is not the same as the official MOS Technology 6502C.
• RAM: 4 KB of memory (two 6116 2Kx8 RAM ICs).
• ROM: The system includes 4 KB of built-in BIOS ROM (NTSC) or 16 KB of BIOS and Asteroids ROM (PAL). There is 48 KB of General Purpose space for ROM, RAM, and other functions without bank switching.
• Graphics: Powered by the MARIA custom chip. Resolution options: 160×240 (160×288 PAL) or 320×240 (320×288 PAL). Color palette: 256 colors (16 hues × 16 brightness levels). Graphics modes limit usable colors and colors per sprite. Direct Memory Access (DMA) is available but can be disabled. Note: DMA Modes 0 and 1 should not be used, as they may cause system issues. Programmers should use DMA Mode 2 or 3 instead. Graphics clock: 7.16 MHz (NTSC), 7.09 MHz (PAL). Line buffer: 200 bytes (double buffering), 160 sprite pixels per scanline, up to 30 sprites per scanline (without background), up to 100 sprites on screen. Sprite/zone sizes: Up to 32 bytes wide (pixel count depends on video mode), height of 1 to 16 pixels. Colors per sprite: 1 to 12 (1 to 12 visible colors, 1 to 4 transparent/background colors). Video Modes:
• 160A: 160-pixel mode, 2bpp sprites (Read Mode 0, Write Mode 0), up to 128-pixel wide sprites, all 25 colors available.
• 160B: 160-pixel mode, 4bpp sprites (Read Mode 0, Write Mode 1), up to 64-pixel wide sprites, all 25 colors available. Read Mode 1 does not exist.
• 320D: 320-pixel mode, 1bpp sprites (Read Mode 2, Write Mode 0), up to 256-pixel wide sprites, 7 colors available.
• 320B: 320-pixel mode, 2bpp sprites (Read Mode 2, Write Mode 1), up to 128-pixel wide sprites, 7 colors available.
• 320A: 320-pixel mode, 1bpp sprites (Read Mode 3, Write Mode 0), up to 256-pixel wide sprites, 9 colors available.
• 320C: 320-pixel mode, 2bpp sprites (Read Mode 3, Write Mode 1), up to 128-pixel wide sprites, 9 colors available.
• I/O: Joystick and console switch input is managed by the 6532 RIOT and TIA chips.
• Ports: Two joystick ports, cartridge port, expansion connector (only on rev 1 boards), power input, and RF output.
• Sound: The TIA chip, used in the 2600 for video and sound, is used only for sound in 7800 mode. At least three games include a POKEY sound chip for improved audio.

Graphics are generated by the MARIA chip, which uses a method common in arcade systems and differs from second- and third-generation consoles. Instead of limited hardware sprites, MARIA processes everything as a sprite using display lists. Each display list contains pointers to graphics data, color, and positioning details.

MARIA supports 256 colors and two graphics resolutions: 160 pixels wide or 320 pixels wide. While 320-pixel modes allow higher resolution than the Nintendo Entertainment System and Master System, most games use the 160-pixel mode due to MARIA’s processing demands.

Each sprite can use 1 to 12 colors, with 3 colors plus transparency being most common. Sprites reference one of 8 palettes, each holding 3 colors. The background can also be assigned a color. Up to 25 colors can appear on a scan line.

Graphics resolution, color palettes, and background color can be adjusted between scan lines.

The 7800 uses the TIA chip for two-channel audio, the same chip used in the 1977 Atari VCS. To improve sound quality, some games include a POKEY chip. Official

Peripherals

The Atari 7800 came with the Atari Pro-Line Joystick, a two-button controller that included a joystick for movement. The Pro-Line was created for the Atari 2600 and promoted in 1983, but its release was delayed until Atari began making the 7800. On the 7800, the right fire button only functions as a separate fire button for some games. For other games, it acts the same as the left fire button, allowing either button to be used for games originally made for the 2600. Although the 7800’s controllers physically fit with the Master System, they do not work with it. Similarly, Sega’s controllers cannot use the 7800’s two-button mode.

Because of comfort problems with the Pro-Line controllers, Atari released a joypad controller for the European version of the 7800. This controller had a design similar to those on Nintendo and Sega systems. It was not sold in the United States.

The XG-1 light gun, which came with the Atari XEGS and was also sold separately, works with the 7800. Atari released five light gun games for the 7800: Alien Brigade, Barnyard Blaster, Crossbow, Meltdown, and Sentinel.

After Jack Tramiel bought the Atari Consumer Division in 1984, several expansion options for the 7800 were cancelled:

• The High Score Cartridge was made to save high scores from up to 65 different games. It worked like a pass-through device, similar to the later Game Genie. Nine games were made to work with the cartridge.
• A computer keyboard with an SIO port and audio input/output ports for a cassette storage device was planned. The keyboard connected to a controller port and allowed standard Atari 8-bit computer hardware to be used. However, it did not make the 7800 compatible with Atari computer software.
• The expansion port for connecting to laserdisc players and other devices was removed in later versions of the 7800.
• A dual joystick holder was designed for Robotron: 2084 and future games like Battlezone, but it was never made.
• A 7800 cartridge adaptor was planned to make the 7800 compatible with the Atari 5200. It would have been a 7800 circuit board designed to fit into the 5200’s cartridge slot, similar to the VCS Cartridge Adaptor.

Games

The Atari 7800 system could play over 400 games from the Atari 2600, but only 59 games were officially released for the 7800. The selection focused on high-quality versions of games from the golden age of arcade video games. By the time the 7800 launched in 1986, games like Pole Position II, Dig Dug, and Galaga were already 3, 4, and 5 years old, respectively. A version of the 1979 game Asteroids was released in 1987. In 1988, Atari published a version of Donkey Kong, which was seven years old when it first appeared in arcades and five years old when it was released on the Atari 8-bit computer. Atari also offered a line of games called "Super Games," which included arcade and computer games that had not previously been playable on a home console, such as One-On-One Basketball and Impossible Mission.

Eleven games were developed and sold by three third-party companies—Absolute Entertainment, Activision, and Froggo—under their own labels. The remaining games were published by Atari Corporation. Most of the games made by Atari were created by outside companies under contract.

Some games for the Nintendo Entertainment System (NES) were developed by companies that had licensed their rights from other arcade manufacturers. While the creator of an NES version could not make a competing version of the same game, the original arcade copyright holder could still license rights for a home version of an arcade game to multiple systems. This allowed Atari 7800 versions of games like Mario Bros., Double Dragon, Commando, Rampage, Xenophobe, Ikari Warriors, and Kung-Fu Master to be made and released.

In 1990, Atari released a final set of games: Alien Brigade, Basketbrawl, Fatal Run, Meltdown, Midnight Mutants, Motor Psycho, Ninja Golf, Planet Smashers, and Scrapyard Dog. Later, Scrapyard Dog was released for the Atari Lynx.

Legacy

In 2004, the version of Atari owned by Infogrames released the Atari Flashback console. This device looks like a small version of the Atari 7800 and includes five games from the 7800 and fifteen games from the 2600. Instead of using the original Atari 7800 hardware, it used a different type of hardware called famiclone. This choice led to criticism because the console did not accurately recreate the original gaming experience. A later project to make a new 7800 console was stopped after some early models were created.

On November 29, 2024, Atari and Plaion released the Atari 7800+, a small console designed to look like the European version of the 7800. It supports physical cartridges for both the 2600 and 7800 through emulation. This console is similar to the Atari 2600+, which was released in 2023.

A digital signature system had previously stopped people from creating new games for the Atari 7800. The software used to create these signatures was discovered and shared at the Classic Gaming Expo in 2001. This allowed the development of new Atari 7800 games, including Beef Drop, B*nQ, Combat 1990, CrazyBrix, Failsafe, and Santa Simon.

In July 2009, the source code for 13 games, the operating system, and development tools for the Atari ST were made public. This included commented assembly language code for the games Centipede, Commando, Crossbow, Desert Falcon, Dig Dug, Food Fight, Galaga, Hat Trick, Joust, Ms. Pac-Man, Super Stunt Cycle, Robotron: 2084, and Xevious.