View source for Atari 8-bit computers

{{Short description|1979-1991 home computer series}}
{{Use mdy dates|date=April 2016}}
{{Being merged|dir=from |target=Atari 800XL |date=November 2025}}
{{Infobox computer
| logo=[[File:Atari 400 logo-02.svg|frameless|upright=0.5]]<br>[[File:Atari 800 logo-01.svg|frameless|upright=0.5]]
| image = Atari-800-Computer-FL.jpg
| caption = The Atari 800's nameplate is on the dual-width cartridge slot cover.
| manufacturer = {{plainlist|
*[[Atari, Inc.]] (1979–1984)
*[[Atari Corporation]] (1984–1992)}}
| type = [[Home computer]]
| release date = {{Start date and age|1979|11}}<ref name=fc2019>{{cite news |url=https://www.fastcompany.com/90432140/how-atari-took-on-apple-in-the-1980s-home-pc-wars |title=How Atari took on Apple in the 1980s home PC wars |author=Benj Edwards |date=2019-12-21 |publisher=[[Fast Company]] }}</ref><ref name=atari50>{{cite news |url=https://www.pcmag.com/news/atari-turns-50-a-look-back-on-the-original-name-in-video-games |title=Atari Turns 50: A Look Back on the Original Name in Video Games |author =Jamie Lendino|date=2022-06-27 |publisher=[[PC Magazine]]}}</ref>
| discontinued = {{End date and age|1992|1|1}}
| cpu = [[MOS Technology 6502|MOS Technology 6502B]] or<br>MOS Technology 6502 SALLY{{plainlist|
*@ {{val|1.79 |u=MHz}} ([[NTSC]])
*@ {{val|1.77 |u=MHz}} ([[PAL]])}}
| graphics = {{nowrap|384 pixels per TV line}}, {{nowrap|256 colors}}, [[sprite (computer graphics)|8 × sprites]], {{nowrap|[[raster interrupt]]s}}
| sound = {{nowrap|4 × [[Electronic oscillator|oscillators]] with [[White noise machine|noise mixing]]}}<br>or 2 × [[amplitude modulation|AM]] digital
| connectivity = {{plainlist|
*{{nowrap|2 or 4 × [[Atari joystick port]]}}
*1 × {{nowrap|[[Atari SIO]]}}
*0–1 × [[Parallel Bus Interface|PBI]]
*0–1 × Composite monitor
*{{nowrap|1–2 × [[ROM cartridge]]}}}}
| os = Custom<br>{{nowrap|[[Atari DOS]] (optional)}}
| units sold = {{val|4 |u=million}}{{citation needed|date=December 2024}}
| baseprice = {{plainlist|
* Atari 400: {{US$|550|1979|round=-1}}
* Atari 800: {{US$|1000|1979|round=-1}}<ref name=prices>{{cite journal|journal=Creative Computing|date=August 1979|volume=5|issue=8|page=26|url=http://mcurrent.name/atari1979/|title=Atari introduces the 400/800 computers}}</ref>}}
| successor = [[Atari ST]]
| related = [[Atari 5200]]
}}

The '''Atari 8-bit computers''', formally launched as the '''Atari Home Computer System''',<ref>{{cite book|title=Atari 800 Home Computer System Salesperson's Guide|year=1982|publisher=Atari, Inc. |url=https://archive.org/details/Atari800HomeComputerSystemSalespersonsGuide}}</ref> are a series of [[home computer]]s introduced by [[Atari, Inc.]], in 1979 with the Atari 400 and Atari 800.<ref>[https://www.pcworld.com/article/225776/history-atari-computers.html Atari's PC Evolution] The History of Atari Computers, Benj Edwards, ''PC World'' April 21, 2011, retrieved August 20 2016.</ref> The architecture is designed around the [[8-bit]] [[MOS Technology 6502]] [[central processing unit|CPU]] and three custom [[coprocessor]]s which provide support for [[sprite (computer graphics)|sprite]]s, smooth multidirectional scrolling, four channels of audio, and other features. The graphics and sound are more advanced than most of its contemporaries, and video games are a key part of the software library. The 1980 first-person space combat simulator ''[[Star Raiders]]'' is considered the platform's [[killer application|killer app]].

The Atari 800 was positioned as a high-end model and the 400 as more affordable. The 400 has a pressure-sensitive, spillproof [[membrane keyboard]] and initially shipped with a non-upgradable {{nowrap|8 KB}} of RAM. The 800 has a conventional keyboard, a second cartridge slot, and allows easy RAM upgrades to 48K. Both use identical 6502 CPUs at {{val|1.79|u=MHz}} ({{val|1.77 |u=MHz}} for PAL versions) and coprocessors [[ANTIC]], [[POKEY]], and [[CTIA and GTIA|CTIA/GTIA]]. The plug-and-play [[peripheral]]s use the [[Atari SIO]] [[serial bus]], and one of the SIO developers eventually went on to co-patent [[USB]] (Universal Serial Bus).<ref name=atarihistory/> The architecture of the Atari 8-bit computers was reused in the 1982 [[Atari 5200]] game console, but games for the two systems are incompatible.

The 400 and 800 were replaced by multiple computers with identical core technology and different presentation. The 1200XL was released in early 1983 to supplant the 800. It was discontinued in June 1983, but the [[industrial design]] carried over to the 600XL and bestselling 800XL released later the same year. After the company was sold and reestablished, [[Atari Corporation]] released the 65XE (called the 800XE in some European markets) and 130XE in 1985. The XL and XE are lighter in construction, have two [[Atari joystick port|joystick port]]s instead of four, and [[Atari BASIC]] is built-in. The 130XE has 128 KB of [[Bank switching|bank-switched]] RAM. In 1987, after the [[Nintendo Entertainment System]] reignited the console market, Atari Corporation packaged the 65XE as a game console, with an optional keyboard, as the [[Atari XEGS]]. It is compatible with 8-bit computer software and peripherals.

The 8-bit computers were sold both in computer stores and department stores such as [[Sears]] using a demo to attract customers.<ref>{{cite web|title=Atari 800 in store demo|url=http://games.greggman.com/game/atari_800_in_store_demo/|website=games.greggman.com|access-date=February 6, 2016|archive-date=March 7, 2021|archive-url=https://web.archive.org/web/20210307120703/https://games.greggman.com/game/atari_800_in_store_demo/|url-status=dead}}</ref> Two million Atari 8-bit computers were sold during its major production run between late 1979 and mid-1985.<ref name="reimer">{{Cite web|last=Reimer|first=Jeremy|title=Total Share: Personal Computer Market Share 1975-2010|url-status=live|access-date=2021-11-27|website=Jeremy Reimer|language=en-us|url=https://jeremyreimer.com/rockets-item.lsp?p=137|date=2012-12-07|archive-url=https://web.archive.org/web/20190705092524/http://jeremyreimer.com/rockets-item.lsp?p=137|archive-date=July 5, 2019}}</ref><ref>{{cite news |url=https://arstechnica.com/features/2005/12/total-share/ |title=Total share: 30 years of personal computer market share figures |author=Jeremy Reiner |date=2005-12-15 |publisher=ArsTechnica }}</ref> The primary global competition came when the similarly equipped [[Commodore 64]] was introduced in August 1982. In 1992, Atari Corporation officially dropped all remaining support for the 8-bit line.<ref name="droppedsupport">{{cite magazine |last=Poehland |first=Ben |date=December 1992 |title=Editor's Desk |url=https://archive.org/details/Atari_Classics_v1n1_Dec_1992/page/n3 |access-date=April 6, 2021 |magazine=Atari Classics |volume=1 |issue=1 |publisher=Unicorn Publications |publication-place=Ann Arbor, MI |page=4}}</ref>

== History ==

Design of the "Home Computer System" started at Atari as soon as the [[Atari 2600|Atari Video Computer System]] was released in late 1977. While designing the VCS in 1976, the engineering team from Atari Grass Valley Research Center (originally [[Cyan Engineering]])<ref>{{cite web |last=Fulton |first=Steve |title=The History of Atari: 1971-1977 |website=[[Game Developer (website)|Gamasutra]] |date=November 6, 2007 |at=para. 1974: The Crunch Hits |url=https://www.gamedeveloper.com/business/the-history-of-atari-1971-1977 |access-date=2023-07-23}}</ref> said the system would have a three-year lifespan before becoming obsolete. They started planning for a console that would be ready to replace it around 1979.<ref name=joe/>

They developed essentially a greatly updated version of the VCS, fixing its major limitations, but sharing a similar philosophy.<ref name=joe>{{cite conference |last=Decuir |first=Joe |author-link=Joseph C. Decuir |date=1999-08-15<!--Date taken from CGExpo99 program https://archive.org/details/classicgamingexpo1999/page/n6 --> |title=3 Generations of Game Machine Architecture |type=Presentation |url=https://www.atariarchives.org/dev/CGEXPO99.html |access-date=2023-07-16 |archive-url=https://web.archive.org/web/20230716120337/https://www.atariarchives.org/dev/CGEXPO99.html |archive-date=July 16, 2023 |conference=Classic Gaming Expo '99 |work=AtariArchives |location=Las Vegas |url-status=dead }}</ref> The newer design has better speed, graphics, and sound. Work on the chips for the new system continued throughout 1978 and focused on a much-improved video coprocessor known as the [[CTIA and GTIA|CTIA]] (the VCS version was the TIA).<ref>{{cite book|title=Atari Home Computer Field Service Manual - 400/800|publisher=Atari, Inc. |url=http://www.digitpress.com/library/techdocs/Atari_400-800_Service_Manual.pdf|pages=1–10}}</ref>

During the early development period, the home computer era began in earnest with the [[TRS-80]], [[Commodore PET|PET]], and [[Apple II (1977 computer)|Apple II]]—what [[Byte (magazine)|''Byte'']] magazine dubbed the "1977 Trinity".<ref>{{cite web|url=http://www.byte.com/art/9509/sec7/art15.htm|title=Most Important Companies|access-date=June 10, 2008|date=September 1995|work=[[Byte (magazine)|Byte Magazine]]|archive-url=https://web.archive.org/web/20080618072507/http://www.byte.com/art/9509/sec7/art15.htm|archive-date=June 18, 2008|url-status=dead}}</ref> [[Nolan Bushnell]] sold Atari to [[Warner Communications]] for {{US$|28 million}} in 1976 to fund the launch of the VCS.<ref>{{Cite book |last=Fisher |first=Adam |url=https://www.worldcat.org/title/on1042088095 |title=Valley of genius: the uncensored history of Silicon Valley, as told by the hackers, founders, and freaks who made it boom |date=2018 |publisher=Twelve |isbn=978-1-4555-5902-2 |edition= |location=New York |oclc=on1042088095}}</ref> In 1978, Warner hired [[Ray Kassar]] as CEO of Atari. Kassar wanted the chipset used in a home computer to challenge Apple,<ref name=atarihistory>{{cite web|title=Computer Systems|website=Atari|url=http://www.atarimuseum.com/computers/computers.html|access-date=September 23, 2019|archive-date=May 5, 2021|archive-url=https://web.archive.org/web/20210505141552/http://www.atarimuseum.com/computers/computers.html|url-status=dead}}</ref> so it needed character graphics, some form of expansion for [[peripheral]]s, and run the then-universal [[BASIC]] programming language.<ref name=joe/>

Atari engineer [[Jay Miner]] created a display architecture for the Atari 8-bit computer consisting of two chips. The CTIA chip handles sprites and background graphics, but to reduce load on the main CPU, loading video registers and buffers is delegated to a dedicated microprocessor, the Alphanumeric Television Interface Controller or [[ANTIC]]. CTIA and ANTIC work together to produce a complete display, with ANTIC fetching [[scan line]] data from a [[framebuffer]] and sprite memory in RAM, plus character set bitmaps for character modes, and feeding these to the CTIA. CTIA processes the sprite and playfield data via its own color, sprite, and graphics registers to produce the final color video output.<ref name=dere>{{cite book|last=Crawford | first=Chris|title=De Re Atari |publisher=Atari|year=1982|url=http://www.atariarchives.org/dere/}}</ref>

The resulting system was far in advance of anything on the market. [[Commodore International|Commodore]] was developing a video driver at the time, but [[Chuck Peddle]], lead designer of the [[MOS Technology 6502]] CPU used in the VCS and the new machines, saw the Atari work during a visit to Grass Valley. He realized the Commodore design would not be competitive but he was under a strict [[non-disclosure agreement]] with Atari, and was unable to tell anyone at Commodore to give up on their own design. Peddle later commented that "the thing that Jay did, just kicked everybody's butt."<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/enHF9lMseP8 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20191004084119/https://www.youtube.com/watch?v=enHF9lMseP8 Wayback Machine]{{cbignore}}: {{Cite interview |title=Oral History of Chuck Peddle |last= Peddle |first=Chuck | interviewer = Doug Fairbairn and Stephen Diamond |date=12 June 2014 |url=https://www.youtube.com/watch?v=enHF9lMseP8 |at=1:56:30}}{{cbignore}}</ref>

=== Development ===

Management identified two [[Sweet spot (economics)|sweet spot]]s for the new computers: a low-end version known internally as "Candy", and a higher-end machine known as "Colleen" (named after two Atari secretaries).<ref>{{cite web|author=Fulton, Steve|url=https://www.gamasutra.com/view/feature/3766/atari_the_golden_years__a_.php?page=4|archive-url=https://web.archive.org/web/20080825070844/http://www.gamasutra.com/view/feature/3766/atari_the_golden_years__a_.php?page=4|url-status=dead|archive-date=August 25, 2008|title=Atari: The Golden Years &nbsp; A History, 1978&nbsp;1981|website=Gamasutra|date=August 21, 2008|page=4}}</ref> Atari would market Colleen as a computer and Candy as a game machine or hybrid game console. Colleen includes user-accessible expansion slots for [[Random-access memory|RAM]] and [[Read-only memory|ROM]], two 8&nbsp;KB [[ROM cartridge]] slots, [[RF modulator|RF]] and [[composite video|monitor output]] (including two pins for separate luma and chroma suitable for superior [[S-Video]] output) and a full keyboard. Candy was initially designed as a game console, lacking a keyboard and input/output ports, although an external keyboard was planned for [[Atari joystick port|joystick ports]] 3 and 4. At the time, plans called for both to have a separate audio port supporting [[cassette tape]]s as a storage medium.{{sfn|Goldberg|Vendel|2012|p=455}}

A goal for the new systems was user-friendliness. One executive stated, "Does the end user care about the architecture of the machine? The answer is no. 'What will it do for me?' That's his major concern. ... why try to scare the consumer off by making it so he or she has to have a [[electrical engineering|double E]] or be a computer programmer to utilize the full capabilities of a personal computer?" For example, cartridges were expected to make the computers easier to use.<ref name=tomczyk>{{cite book|chapter-url=http://www.atariarchives.org/c1ba/page002.php|title=Compute!'s First Book of Atari|publisher=Compute! Books|author=Tomczyk, Michael S.|author-link=Michael Tomczyk|year=1981|pages=2|isbn=0-942386-00-0|chapter=Atari's Marketing Vice President Profiles the Personal Computer Market}}</ref> To minimize handling of bare circuit boards or chips, as is common with other systems of that period, the computers were designed with enclosed modules for memory, ROM cartridges, with keyed connectors to prevent them being plugged into the wrong slot. The operating system boots automatically, loading drivers from devices on the serial bus (SIO). The [[#Disk Operating System|disk operating system]] for managing floppy storage was menu-driven. When no software is loaded, rather than leaving the user at a blank screen or machine language monitor, the OS goes to the "Memo Pad" which is a built-in full-screen editor without file storage support.<ref name=dere/>

As the design process for the new machines continued, there were questions about what the Candy should be. There was a running argument about whether the keyboard would be external or built-in.{{sfn|Goldberg|Vendel|2012|p=456}} By the summer of 1978, education had become a focus for the new systems. The Colleen design was largely complete by May 1978, but in early 1979 the decision was made that Candy would also be a complete computer, but intended for children. As such, it would feature a new keyboard designed to be resistant to liquid spills.{{sfn|Goldberg|Vendel|2012|p=460}}

Atari intended to port [[Microsoft BASIC]] to the machine as an 8&nbsp;[[kilobyte|KB]] ROM cartridge. However, the existing 6502 version from Microsoft was around 7,900&nbsp;bytes, leaving no room for extensions for graphics and sound. The company contracted with local consulting firm [[Shepardson Microsystems]] to complete the port. They recommended writing a new version from scratch, resulting in [[Atari BASIC]].<ref>{{cite book|author=Wilkinson, Bill|title=Inside Atari Basic|publisher=COMPUTE! Books|year=1982 |url=http://www.atariarchives.org/iad/introduction.php}}</ref>

=== FCC issues ===

Televisions of the time normally had only one input: the antenna connection. For devices like a computer, the video is generated and then sent to an [[RF modulator]] to convert it to antenna-like output. The introduction of many game consoles during this era led to situations where poorly designed modulators generated so much signal as to cause interference with other nearby televisions, even in neighboring houses. In response to complaints, the [[Federal Communications Commission]] (FCC) introduced new testing standards which are extremely exacting and difficult to meet.{{sfn|Goldberg|Vendel|2012|p=466}}

To meet the FCC requirements, both new machines were built around cast aluminum shields forming a partial [[Faraday cage]], with the various components screwed onto this internal framework. This resulted in a sturdy computer, at the disadvantage of added manufacturing expense and complexity.<ref name=atarihistory/>

The FCC ruling also made it difficult to have any sizable holes in the case, which would allow RF leakage. This eliminated expansion slots or cards that communicated with the outside world via their own connectors. Instead, Atari designed the [[Atari SIO|Serial Input/Output]] (SIO) [[Bus (computing)|computer bus]]: a system for daisy-chaining multiple, auto-configuring devices to the computer through a single shielded connector. The internal slots are reserved for ROM and RAM modules; they do not have the control lines necessary for a fully functional expansion card, nor room to route a cable outside the case to communicate with external devices.<ref name=atarihistory/>

=== 400 and 800 release ===
[[File:Atari-400-Comp.jpg|thumb|Atari 400 (1979) has a [[membrane keyboard]] and a door covering the single cartridge slot.]]
[[File:Atari-800-Computer-FL-No-Cover-Expansions.jpg|thumb|Atari 800 with the cover removed, showing expansion cards and two cartridge slots. The slots are molded into the cast aluminum RF shield.]]
[[File:Atari-800-Expansion-Board-16K-RAM.jpg|thumb|The Atari 800 has expansion cards for the RAM, ROM, and processor. It eventually shipped with three of these 16KB RAM cards, for a total of 48KB.]]

After Atari announced its intent to enter the home computer market in December 1978,<ref>{{cite news|last=Schuyten | first=Peter J.|title=Technology; The Computer Entering Home|newspaper=[[The New York Times]]|department=Business & Finance|date=December 6, 1978|page=D4|issn=0362-4331}}</ref> the Atari 400 and Atari 800 were presented at the Winter [[Consumer Electronics Show|CES]] in January 1979<ref>{{cite magazine|author=Craig, John|date=April 1979|title=Winter Consumer Electronics Show|url=https://archive.org/details/creativecomputing-1979-04|access-date=May 25, 2014| magazine=[[Creative Computing]]|volume=5|issue=4|page=16}}</ref> and shipped in November 1979.<ref name=fc2019 /><ref name=atari50 />

The names originally referred to the amount of memory: 4&nbsp;KB RAM in the 400 and 8&nbsp;KB in the 800. By the time they were released, RAM prices had started to fall, so the machines were both released with 8&nbsp;KB, using 4kx1 DRAMs. The user-installable RAM modules in the 800 initially had plastic casings but this caused overheating issues, so the casings were removed. Later, the expansion cover was held down with screws instead of the easier-to-open plastic latches.<ref>{{cite web|title=The Atari 800| last=Vendel | first=Curt|website=Atari Museum|url=http://www.atarimuseum.com/computers/8bits/400800/atari800/a800.html|access-date=October 20, 2016|archive-date=December 8, 2012|archive-url=https://archive.today/20121208194608/http://www.atarimuseum.com/computers/8BITS/400800/ATARI800/A800.html|url-status=dead}}</ref> The computers eventually shipped with maxed-out RAM: 16k and 48k, respectively, using 16kx1 DRAMs.

Both models have four joystick ports, permitting four simultaneous players, but only a few games (such as ''[[M.U.L.E.]]'') use them all. Paddle controllers are wired in pairs, and ''[[Super Breakout]]'' supports eight players.{{r|edwards}} The Atari 400, with a [[membrane keyboard]] and single internal ROM slot, outsold the Atari 800 by a 2-to-1 margin.<ref name="reimer"/> Only one cartridge for the 800's right slot was produced by March 1983, and later machines in the series have only one slot.<ref name="halfhill198303">{{cite news|url=http://www.atarimagazines.com/compute/issue34/025_1_ATARIS_NEW_TOP-LINE_HOME_COMPUTER.php|title=Atari's New Top-Line Home Computer|work=Compute!|date=March 1983|access-date=June 30, 2014|last=Halfhill |first=Tom R.|page=66}}</ref><ref name=edwards>{{cite web|url=http://www.pcworld.com/article/181421/inside_atari_800.html|title=Inside the Atari 800|work=PC World|date=November 4, 2009|access-date=July 19, 2014|last=Edwards |first=Benj}}</ref>

''[[Creative Computing (magazine)|Creative Computing]]'' mentioned the Atari machines in an April 1979 overview of the CES show. Calling Atari "the videogame people", it stated they came with "some fantastic educational, entertainment and home applications software".<ref>{{cite magazine|magazine=Creative Computing|date=April 1979|url=https://archive.org/stream/CreativeComputingbetterScan197904#page/n17|page=16|title=Winter Consumer Electronics Show|last=Craig | first=John}}</ref> In an August 1979 interview Atari's Peter Rosenthal suggested that demand might be low until the 1980–81 time frame, when he predicted about one million home computers being sold.<ref>{{cite magazine|magazine=Creative Computing|date=August 1979|url=https://archive.org/stream/CreativeComputingbetterScan197908#page/n59|pages=58–59 |title=Atari Speaks Out| last=Ahl | first=David}}</ref> The April 1980 issue compared the machines with the [[Commodore PET]], focused mostly on the BASIC dialects.<ref>{{cite magazine|magazine=Creative Computing|date=April 1980 |url=https://archive.org/details/CreativeComputingbetterScan198004/page/n23/mode/1up|pages=22–30|title=Atari in Perspective|last=Lindsay | first=Len}}</ref> [[Ted Nelson]] reviewed the computer in the magazine in June 1980, calling it "an extraordinary graphics box". Describing his and a friend's "shouting and cheering and clapping" during a demo of ''[[Star Raiders]]'', Nelson wrote that he was so impressed that "I've been in computer graphics for twenty years, and I lay awake night after night trying to understand how the Atari machine did what it did". He described the machine as "something else" but criticized the company for a lack of developer documentation. He concluded by stating "The Atari is like the human body – a terrific machine, but (a) they won't give you access to the documentation, and (b) I'd sure like to meet the guy that designed it".<ref name=nelson198006>{{cite magazine|url=https://archive.org/details/CreativeComputingbetterScan198006/page/n35|pages=34–35, 37|title=The Atari Machine|magazine=Creative Computing|date=June 1980|last=Nelson |first=Ted}}</ref> ''[[Kilobaud Microcomputing]]'' wrote in September 1980 that the Atari 800 "looks deceptively like a video game machine, [but had] the strongest and tightest chassis I have seen since [[Raquel Welch]]. It weighs about ten pounds ... The large amount of engineering and design in the physical part of the system is evident". The reviewer praised the documentation as "show[ing] the way manuals should be done", and the "excellent 'feel{{'"}} of the keyboard.<ref>{{cite magazine|url=https://archive.org/stream/kilobaudmagazine-1980-09/Kilobaud_Microcomputing_1980_September#page/n97/mode/2up|title=Moonshine, Dixie and the Atari 800|magazine=Kilobaud |date=September 1980|access-date=June 23, 2014|last=Derfler |first=Frank J. Jr.|pages=100–103}}</ref> ''[[InfoWorld]]'' favorably reviewed the 800's performance, graphics, and ROM cartridges, but disliked the documentation and cautioned that the unusual right Shift key location might make the computer "unsuitable for serious word processing". There is an "Atari key" between the {{key|/}} and shift, whereas a typical keyboard would extend the shift key into this area. Noting that the amount of software and hardware available for the computer "is no match for that of the Apple II or the TRS-80", the magazine concluded that the 800 "is an impressive machine that has not yet reached its full computing potential".<ref name="hogan19810511">{{cite magazine|title=The Atari 800 Personal Computer|magazine=InfoWorld|date=May 11, 1981| last=Hogan | first=Thom|pages=34–35}}</ref>

===400/800 evolution===

In October–November 1981, Atari began shipping the 400 and 800 with the GTIA chip instead of the CTIA chip used since launch.<ref>{{cite journal |last=Mace |first=Scott |date=1982-03-15 |title=Atari quietly switches to a 16-color graphics chip |journal=[[InfoWorld]] |volume=4 |issue=10 |pages=3–4 |publisher=Popular Computing |location=Palo Alto, CA |issn=0199-6649 |url=https://books.google.com/books?id=gD4EAAAAMBAJ&pg=PA3 |access-date=2011-02-01}}</ref><ref>{{cite web |last1=Jung |first1=Robert A. |title=The Atari Timeline |url=https://www.landley.net/history/mirror/atari/museum/Atari-Timeline.html |website=Landley}}</ref> Existing computers could be upgraded. GTIA adds three graphics modes with more colors, but at a low horizontal resolution ({{resx|80|192}}).<ref name="compute-26">{{cite journal |last=Chamberlain |first=Craig |date=July 1982 |title=Atari Video Graphics And The New GTIA |journal=[[Compute!]] |issue=26 |page=124 |issn=0194-357X |url=http://www.atarimagazines.com/compute/issue26/Atari_Video_Graphics_And_The_New_GTIA.php |access-date=2011-01-24}}</ref> Some later software relies on GTIA modes such as ''[[Koronis Rift]]'' and ''[[Space Lobsters]]''.

Circa 1982, the base memory in both models increased: from 8K to 16K for the Atari 400 and from 16K to 48K for the Atari 800.{{Citation needed|date=June 2025}}

=== Sweet/Liz project ===

Though planning an extensive advertising campaign for 1980,{{r|tomczyk}} Atari found difficult competition from Commodore, Apple, and Tandy. By mid-1981, it had reportedly lost $10 million on sales of $10–13 million from more than 50,000 computers.<ref name="hogan19810831">{{cite magazine|title=From Zero to a Billion in Five Years|magazine=InfoWorld|date=August 31, 1981|author=Hogan, Thom|pages=6–7}}</ref><ref name="hogan19810914state">{{cite magazine| magazine=[[InfoWorld]] | title=State of Microcomputing: Some Horses Running Neck and Neck| first=Hogan | last=Thom|date=September 14, 1981| url={{Google Books | id=Mj0EAAAAMBAJ | page=10 | plainurl=yes}} | pages=10–12 | access-date=February 9, 2023}}</ref>

In 1982, Atari started the Sweet 8 (also called Liz NY) and Sweet 16 projects to create new machines that were easier to build and less costly to produce. Atari ordered a custom 6502 with logic to disable the clock signal, called <code>HALT</code>, which ANTIC uses to shut off the CPU to access the data/address bus.{{sfn|Current|2023|loc=1.12) What are SALLY, ANTIC, CTIA/GTIA/FGTIA, POKEY, and FREDDIE?}} This "SALLY" CPU was incorporated into late-production 400 and 800 models, all XL/XE models, and the [[Atari 5200]] and [[Atari 7800]] consoles.

Mirroring the 400/800, two systems were planned, the 1000 with 16&nbsp;KB and the 1000X with 64&nbsp;KB, each expandable via a [[Parallel Bus Interface]] slot on the back of the machine.

=== 1200XL===
[[File:Atari 1200XL.jpg|thumb|Atari 1200XL]]

The original Sweet 8/16 plans were dropped and only one machine using elements of the new design was released. Announced at a New York City press conference on December 13, 1982,<ref>{{cite press release|title=Atari introduces the 1200XL computer|url=http://mcurrent.name/atari1983/|place=New York|publisher=[[Atari, Inc.]]|date=December 13, 1982|agency=[[PR Newswire]]}}</ref><ref name="creative-atari-1200xl">{{cite book|author=Anderson, John|title=The Creative Atari|chapter=New Member of the Family - Atari 1200|chapter-url=http://www.atariarchives.org/creativeatari/New_Member_of_the_Family.php|year=1983|publisher=Creative Computing Press|location=Morris Plains, NJ|page=116|url=http://www.atariarchives.org/creativeatari/|access-date=May 7, 2014|isbn=0-916688-34-8|editor=Small, David|editor2=Small, Sandy|editor3=Blank, George}}</ref> the 1200XL was presented at the Winter [[Consumer Electronics Show|CES]] on January 6–9, 1983.<ref name=creative-83-ces>{{cite magazine|author=Ahl, David H.|author2=Staples, Betsy|date=April 1983|title=1983 Winter Consumer Electronics Show; Creative Computing presents the Short Circuit Awards|url=http://www.atarimagazines.com/creative/v9n4/18_1983_Winter_Consumer_Elec.php |archive-url=https://web.archive.org/web/20130702024034/http://www.atarimagazines.com/creative/v9n4/18_1983_Winter_Consumer_Elec.php|archive-date=July 2, 2013|magazine=Creative Computing|volume=9|issue=3|publisher=Ahl Computing|page=50|issn=0097-8140}}</ref> It shipped in March{{citation needed|date=May 2014}} 1983{{sfn|Goldberg|Vendel|2012|p=698|ps=: <q>Released in early 1983, it will only remain in production until June 1983.</q>}} with 64&nbsp;KB of RAM, 2 joysticks ports instead of 4, built-in self test, a redesigned keyboard (with four function keys and a HELP key), redesigned cable port layout,{{r|halfhill198303}} and a case designed by Regan Cheng.<ref name=cfch1200>{{cite web |url=https://www.computinghistory.org.uk/det/22449/Atari-1200XL/ |website=Centre for Computing History |title=Atari 1200XL}}</ref> There is no PAL version of the 1200XL.<ref name=cfch1200/>

Announced at a retail price of $1000,<ref name="lock198306">{{cite magazine|url=https://archive.org/stream/1983-06-compute-magazine/Compute_Issue_037_1983_Jun#page/n7/mode/2up|title=Editor's Notes|magazine=Compute!|date=June 1983|access-date=October 30, 2013|author=Lock, Robert|pages=6}}</ref> the 1200XL was released at {{USD|899|1983|about=yes|long=no|round=-2}}.{{r|creative-83-ces}} This is $100 less than the announced price of the Atari 800 at its release in 1979,<ref name=prices/> but by this time the 800 was priced much lower.

The system uses the SIO port again instead of the Parallel Bus Interface. The +12V pin in the SIO port is not connected, which prevents a few devices from working. The +12V was typically used to power RS-232 devices, which now required an external power source. An improved video circuit provides more chroma for a more colorful image, but the chroma line is not connected to the monitor port, the only place that could make use of it. The operating system has compatibility problems with some older software.

The 1200XL was discontinued in June 1983.

''[[Compute!]]'' stated in an early 1983 editorial that the 1200XL was too expensive;<ref name="lock198302">{{cite magazine|url=https://archive.org/stream/1983-02-compute-magazine/Compute_Issue_033_1983_Feb#page/n9/mode/2up|title=Editor's Notes|magazine=Compute!|date=February 1983|access-date=October 30, 2013|author=Lock, Robert|pages=8}}</ref> [[John J. Anderson]] of ''[[Creative Computing (magazine)|Creative Computing]]'' agreed.<ref>{{cite journal|author=Anderson, John|title=Outpost: Atari|url=http://www.atarimagazines.com/creative/v9n5/272_Outpost_atari.php|journal=Creative Computing|date=May 1983|page=272}}</ref> Bill Wilkinson, author of Atari BASIC, co-founder of [[Optimized Systems Software]], and columnist for ''Compute!'', criticized the computer's features and price. He wrote that the 1200XL was a "terrific bargain" if sold for less than $450, but that if it cost more than the 800, "buy an 800 quick!"<ref>{{cite news|url=https://archive.org/stream/1983-05-compute-magazine/Compute_Issue_036_1983_May#page/n199/mode/2up|title=INSIGHT: Atari|work=Compute!|date=May 1983|access-date=October 30, 2013|author=Wilkinson, Bill|pages=198}}</ref>

=== 600XL and 800XL ===
[[File:Atari-800XL.jpg|thumb|The 800XL is the best-selling model.]]
[[File:Atari-600XL-PC.jpg|thumb|The 600XL has a slightly shallower case than the 800XL.]]

In May 1981, the Atari 800's price was {{US$|long=no|1050|1981|round=-2}},{{r|hogan19810511}} but by mid-1983, because of price wars in the industry, it was {{US$|long=no|165|1983|round=-1}}<ref name="bisson198605">{{cite magazine|url=https://archive.org/stream/1986-05-anticmagazine/Antic_Vol_5-01_1986-05_Fourth_Anniversary_Issue#page/n15/mode/2up|title=Antic Then & Now|magazine=Antic|date=May 1986|access-date=January 28, 2015|author=Bisson, Gigi|pages=16–23}}</ref> and the 400 was under {{US$|long=no|150|1983|round=-1}},{{r|lock198306}} down from under {{US$|long=no|300|1982|round=-1}} in 1982.<ref>{{cite news |url=https://time.com/archive/6883869/price-war-in-small-computers/ |title=Price Wars in Small Computers |author=John Greenwald |date=1982-09-20 |publisher=Time }}</ref> The 1200XL was a flop, and the earlier machines were too expensive to produce to be able to compete at the rapidly falling price points.<ref>{{Cite journal |last=Knight |first=John |date=April 2007 |title=''Handbook of Computer Game Studies'' edited by Joost Raessens and Jeffrey Goldstein. MIT Press, Cambridge, MA, U.S.A., 2005. 496 pp., hardcover. ISBN 0-262-18240-8 |url=https://doi.org/10.1162/leon.2007.40.2.207 |journal=Leonardo |volume=40 |issue=2 |pages=207–208 |doi=10.1162/leon.2007.40.2.207 |issn=0024-094X|url-access=subscription }}</ref>

A new lineup was announced at the 1983 Summer [[Consumer Electronics Show]], closely following the original Sweet concepts. The 600XL is essentially the Liz NY model and the spiritual successor of the 400, and the 800XL would replace both the 800 and 1200XL. The machines follow the styling of the 1200XL but are smaller from back to front, and the 600XL is more so.

[[File:Inside Atari 800XL.JPG|thumb|800XL main circuit board]]

Atari had difficulty in transitioning manufacturing to Asia after closing its US factory in 1983.<ref>{{cite news|url=https://www.washingtonpost.com/archive/business/1984/02/06/colecos-adam-gets-gentlemans-c-for-performance/c231169a-0e52-4192-b54f-b2b9f5bfd84d/|title=Coleco's 'Adam' Gets Gentleman's 'C' for Performance|author=Reid, T. R.|date=February 6, 1984|newspaper=The Washington Post|author-link=T. R. Reid}}</ref><ref>{{cite news |url=https://www.nytimes.com/1983/07/08/business/chief-is-replaced-at-troubled-atari.html |title=Chief Is Replaced at Troubled Atari |author=Andrew Pollack |date=1983-07-08 |work=[[New York Times]] }}</ref><ref>{{cite news |url=https://www.latimes.com/archives/la-xpm-1986-06-04-fi-8716-story.html |title=Ex-Workers Win Back Pay for Layoffs Without Notice : Atari Settles Landmark Lawsuit |author=Henry Weinstein |date=1986-06-04 |work=[[Los Angeles Times]] }}</ref> Originally intended to replace the 1200XL in mid-1983, the new models did not arrive until late that year. Although the 600XL/800XL were well positioned in terms of price and features, during the critical Christmas season they were available only in small numbers while the [[Commodore 64]] was widely available.<ref name="reimer"/> [[Brian Moriarty]] stated in ''[[ANALOG Computing]]'' that Atari "fail[ed] to keep up with Christmas orders for the 600 and 800XLs", reporting that as of late November 1983 the 800XL had not appeared in Massachusetts stores while 600XL "quantities are so limited that it's almost impossible to obtain".<ref name="analog198401">{{cite magazine|author=Moriarty, Brian|author-link=Brian Moriarty|author2=Nowell, Robin E.|author3=Franklin, Austin|date=January 1984|title=Inside the Atari 600XL|url=https://archive.org/stream/analog-computing-magazine-15/Analog_Computing_15_1984-01_Inside_the_600XL#page/n33/mode/2up|magazine=ANALOG Computing|page=32}}</ref>

After losing {{US$|long=no|563 million}} in the first nine months of the year, Atari that month announced that prices would rise in January, stating that it "has no intention of participating in these suicidal price wars."<ref>{{cite news|title=Atari, Coleco to Raise Prices of Home Computers on January 1|author=Wessel, David|date=November 10, 1983|work=The Boston Globe}}</ref> The 600XL and 800XL's prices in early 1984 were $50 higher than for the VIC-20 and Commodore 64.<ref>{{cite news|title=Can Atari Bounce Back?|work=InfoWorld|date=February 27, 1984|last=Mace | first=Scott|pages=100}}</ref>

''ANALOG Computing'', writing about the 600XL in January 1984, stated that "the Commodore 64 and [[TRS-80 Color Computer|Tandy CoCo]] look like toys by comparison." The magazine approved of its not using the 1200XL's keyboard layout, and predicted that the XL's parallel bus "actually makes the 600 ''more'' expandable than a 400 or 800." While disapproving of the use of an operating system closer to the 1200XL's than the 400 and 800's, and the "inadequate and frankly disappointing" documentation, ''ANALOG'' concluded that "our first impression ... is mixed but mostly optimistic." The magazine warned, however, that because of "Atari's sluggish marketing", unless existing customers persuaded others to buy the XL models, "we'll all end up marching to the beat of a drummer whose initials are IBM."{{r|analog198401}} By March 1984, all of Atari's computer models were produced in Hong Kong by the Atari-Wong joint venture.<ref>{{cite news |url=https://www.atarimagazines.com/v2n12/atariinternational.html |title=Inside Atari: Atari International |author=Robert DeWitt |date=1984-03-01 |publisher=ANTIC }}</ref>

=== Unreleased XL models ===

The high-end 1400XL and 1450XLD were announced alongside the 600XL and 800XL. They added a built-in 300 baud [[modem]] and a [[voice synthesizer]], and the 1450XLD has a built-in [[Double-sided disk|double-sided]] [[floppy disk]] drive in an enlarged case, with a slot for a second drive. Atari BASIC is built into the [[Read-only memory|ROM]] and the PBI at the back for external expansion.

The 1400XL and the 1450XLD had their delivery dates pushed back, and in the end, the 1400XL was canceled outright, and the 1450XLD so delayed that it would never ship. Other prototypes which never reached market include the 1600XL, 1650XLD, and 1850XLD. The 1600XL was to have been a dual-processor model capable of running 6502 and 80186 code, and the 1650XLD is a similar machine in the 1450XLD case. These were canceled when [[James J. Morgan]] became CEO and wanted Atari to return to its video game roots.<ref>{{Cite web |url=http://www.atarimuseum.com/computers/8BITS/XL/1600xl/1600xl.html |title="Atari 1600XL" |access-date=April 14, 2008 |archive-date=September 13, 2011 |archive-url=https://wayback.archive-it.org/all/20110913014906/http://www.atarimuseum.com/computers/8BITS/XL/1600xl/1600xl.html |url-status=dead }}</ref> The 1850XLD was to have been based on the Lorraine chipset<ref>{{Cite web |url=http://archives.atarimuseum.com/archives/archives.html |title=Afterthoughts: The Atari 1600XL Rumor |access-date=September 19, 2008 |archive-date=April 15, 2009 |archive-url=https://web.archive.org/web/20090415111352/http://archives.atarimuseum.com/archives/archives.html |url-status=dead }}</ref> which became the [[Amiga]].

=== Tramiel takeover, declining market ===

Commodore founder [[Jack Tramiel]] resigned in January 1984 and in July, he purchased the Atari consumer division from Warner for an extremely low price. No cash was required, and instead Warner had the right to purchase {{US$|long=no|240 million}} in long-term notes and warrants, and Tramiel had an option to buy up to {{US$|long=no|100 million}} in Warner stock. When Tramiel took over, the high-end XL models were canceled and the low-end XLs were redesigned into the XE series. Nearly all research, design, and prototype projects were canceled, including the [[Amiga#1850XLD|Amiga-based 1850XLD]]. Tramiel focused on developing the [[Motorola 68000|68000]]-based [[Atari ST]] computer line and recruiting former Commodore engineers to work on it.

Atari sold about 700,000 computers in 1984 compared to Commodore's two million.<ref>{{cite news|title=Trading Up in Computer Gifts|work=The New York Times|date=December 22, 1984|author=Kleinfield, N. R.}}</ref> As his new company prepared to ship the Atari&nbsp;ST in 1985, Tramiel stated that sales of Atari 8-bit computers were "very, very slow".<ref>{{cite news|title=Atari Ships New 520 ST|work=InfoWorld|date=June 3, 1985|author=Maremaa, Tom|pages=23}}</ref> They were never an important part of Atari's business compared to video games, and it is possible that the 8-bit line was never profitable for the company though almost 1.5 million computers had been sold by early 1986.{{r|hogan19810831}}<ref name="pollack19821219">{{Cite news |last=Pollack |first=Andrew |date=1982-12-19 |title=The Game Turns Serious at Atari |language=en-US |page=Section 3, Page 1 |work=The New York Times |url=https://www.nytimes.com/1982/12/19/business/the-game-turns-serious-at-atari.html |access-date=2021-02-18 |issn=0362-4331|url-access=limited}}</ref><ref name=anderson>{{cite news|url=https://archive.org/stream/creativecomputing-1984-03/Creative_Computing_v10_n03_1984_Mar#page/n51/mode/2up|title=Atari|work=Creative Computing|date=March 1984|author=Anderson, John J.|pages=51}}</ref>{{r|bisson198605}}

By that year, the Atari software market was decreasing in size. ''[[Antic (magazine)|Antic]]'' magazine stated in May 1985 that it had received many letters complaining that software companies were ignoring the Atari market, and urged readers to contact the companies' leaders.<ref>{{cite news|url=https://archive.org/stream/1985-05-anticmagazine/Antic_Vol_4-01_1985-05_New_Super_Ataris#page/n7/mode/2up|title=and we won't take it anymore!|work=Antic|date=May 1985|author=Capparell, James|pages=8, 10}}</ref> "The Atari 800 computer has been in existence since 1979. Six years is a pretty long time for a computer to last. Unfortunately, its age is starting to show", ''[[ANALOG Computing]]'' wrote in February 1986. The magazine stated that while its software library was comparable in size to that of other computers, "now—and even more so in the future—there is going to be less software being made for the Atari 8-bit computers", warning that 1985 only saw a "trickle" of major new titles and that 1986 "will be even leaner".<ref>{{cite news|url=https://archive.org/stream/analog-computing-magazine-39/Analog_Computing_39_1986-02_Fifth_Anniversay_and_CES#page/n117/mode/2up|title=The End User|work=ANALOG Computing|date=February 1986|author=Leyenberger, Arthur|pages=109–110}}</ref>

''[[Computer Gaming World]]'' that month stated "games don't come out for the Atari first anymore".<ref name=greggman>{{cite magazine|title=Atari Playfield|magazine=[[Computer Gaming World]]|issue=25|date=January–February 1986|url=http://www.cgwmuseum.org/galleries/issues/cgw_25.pdf|author=Williams, Gregg|pages=32}}</ref> In April, the magazine published a survey of ten game publishers which found that they planned to release 19 Atari games in 1986, compared to 43 for Commodore&nbsp;64, 48 for Apple&nbsp;II, 31 for IBM&nbsp;PC, 20 for Atari ST, and 24 for Amiga. Companies stated that one reason for not publishing for Atari was the unusually high amount of [[Copyright infringement|software piracy]] on the computer, partly caused by the [[Happy Computers|Happy Drive]].<ref>{{cite magazine|title=Survey of Game Manufacturers|magazine=[[Computer Gaming World]]|issue=27|date=April 1986|url=http://www.cgwmuseum.org/galleries/issues/cgw_27.pdf|access-date=April 17, 2016|pages=32}}</ref><ref name=williams>{{cite magazine|title=Atari Playfield|magazine=[[Computer Gaming World]]|issue=31|date=September–October 1986|url=http://www.cgwmuseum.org/galleries/issues/cgw_31.pdf|author=Williams, Gregg|pages=35}}</ref><ref>{{cite magazine|title=Computer Wargaming 1988-1992|magazine=[[Computer Gaming World]]|issue=37|date=May 1987|url=http://www.cgwmuseum.org/galleries/issues/cgw_37.pdf6|author=Brooks, M. Evan|pages=13|access-date=September 23, 2019|archive-date=September 23, 2025|archive-url=https://web.archive.org/web/20250923120032/http://www.cgwmuseum.org/galleries/issues/cgw_37.pdf6|url-status=dead}}</ref> The magazine warned later that year, "Is this the end for Atari 800 games? It certainly looks like it might be from where I write".<ref name=williams/> In 1987, [[MicroProse]] confirmed that it would not release ''[[Gunship (video game)|Gunship]]'' for the Atari 8-bits, stating that the market was too small.<ref>{{cite magazine|title=Titans of the Computer Gaming World / MicroProse|magazine=[[Computer Gaming World]]|issue=41|date=November 1987|url=http://www.cgwmuseum.org/galleries/issues/cgw_41.pdf|author=Brooks, M. Evan|pages=17}}</ref>

=== XE series ===
[[File:Atari-130XE.jpg|thumb|Atari 130XE]]

The 65XE and 130XE (XE stands for XL-Compatible Eight-bit)<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=ROaNQc8IiZE |title=Jack Tramiel - Atari - Rare UK TV Appearance |via=[[YouTube]] |access-date=August 6, 2022 |archive-date=July 24, 2019 |archive-url=https://web.archive.org/web/20190724203243/https://www.youtube.com/watch?v=ROaNQc8IiZE&gl=US&hl=en |url-status=dead }}</ref> were announced in 1985 at the same time as the [[Atari ST|Atari 520ST]], and they visually resemble the ST. The 65XE has 64 KB of RAM and is functionally equivalent to the 800XL minus the PBI connection. The 130XE has 128 KB of memory, accessible through [[bank switching]]. The additional 64K can be used as a [[RAM drive]].

The 130XE includes the Enhanced Cartridge Interface (ECI), which is almost compatible with the Parallel Bus Interface, but physically smaller and located next to the standard 400 and 800 compatible cartridge slot. It provides only those signals that do not exist in the latter. ECI peripherals were expected to plug into both the standard Cartridge Interface and the ECI port. Later revisions of the 65XE contain the ECI port.

The 65XE was sold as the 800XE in [[Germany]] and [[Czechoslovakia]]<ref>{{cite book|title=Breakout: How Atari 8-Bit Computers Defined a Generation|author=Lendino, Jamie|editor=Murray, Matthew|publisher=Ziff Davis|year=2017|page=106|isbn=978-0692851272}}</ref> to ride on the popularity of the 800XL in those markets. All 800XE units contain the ECI port.{{sfn|Current|2023|loc=1.10) What is the Atari 800XE?}}

=== XE Game System ===
{{Main|Atari XEGS}}
[[File:Atari XEGS.jpg|thumb|Atari XE Game System]]

The Atari XEGS (XE Game System) was launched in 1987. A repackaged 65XE with a removable keyboard, it boots to the 1981 port of ''[[Missile Command]]'' instead of BASIC if the keyboard is disconnected.

== Design ==
[[File:Atari-800-Expansion-Board-CPU.jpg|thumb|The processor board for the Atari 800 has the 6502, ANTIC, and CTIA chips.]]

The Atari machines consist of a 6502 as the main processor, a combination of [[ANTIC]] and [[CTIA and GTIA|GTIA]] chips to provide graphics, and the [[POKEY]] chip to handle sound and serial input/output. These support chips are controlled via a series of [[hardware register|register]]s that can be user-controlled via memory load/store instructions running on the 6502. For example, the GTIA uses a series of registers to select colors for the screen; these colors can be changed by inserting the correct values into its registers, which are [[Memory-mapped I/O|mapped into the address space]] that is visible to the 6502.  Some of the coprocessors use data stored in RAM, such as ANTIC's display buffer and [[display list]], and GTIA's Player/Missile ([[sprite (computer graphics)|sprite]]) information.

Atari reportedly spent $10 million to develop its three custom chips.<ref name="lundell19810817">{{Cite magazine |last=Lundell |first=Allan |date=1981-08-17 |title=Computer Animation on Personal Computers |url=https://books.google.com/books?id=pD0EAAAAMBAJ&pg=PT44#v=onepage&q&f=true |access-date=November 13, 2025 |magazine=InfoWorld |pages=40, 44 |volume=3 |issue=16}}</ref> These allow many functions directly in hardware, such as smooth background scrolling, that would need to be done in software in most other systems. Computers running in-store graphics and sound demos were part of Atari's early marketing.<ref name=greggman/>

=== ANTIC ===

[[ANTIC]] is a microprocessor which processes a sequence of instructions known as a [[display list]]. An instruction adds one row of the specified graphics mode to the display. Each mode varies based on whether it represents text or a bitmap, the resolution and number of colors, and its vertical height in [[scan line]]s. An instruction also indicates if it contains an interrupt, if fine scrolling is enabled, and optionally where to fetch the display data from memory.<ref>{{Cite book |last1=Small |first1=David |url=https://books.google.com/books?id=O4Y_AQAAIAAJ |title=The Creative Atari |last2=Small |first2=Sandy |last3=Blank |first3=George |date=1983 |publisher=Creative Computing Press |isbn=978-0-916688-34-9 |language=en |access-date=18 December 2023}}</ref>

Since each row can be specified individually, the programmer can create displays containing different text or bitmapped graphics modes on one screen, where the data can be fetched from arbitrary, non-sequential memory addresses.<ref>{{Cite book |url=https://books.google.com/books?id=9tsnHAAACAAJ |title=De Re Atari Anno Domini MCMLXXXI: A Guide to Effective Programming of the Atari 400/800 Home Computer |date=1981 |publisher=[[Atari, Inc.]] |language=en |access-date=18 December 2023}}</ref>

ANTIC reads this display list and the display data using DMA (Direct Memory Access), then translates the result into a pixel data stream representing the playfield text and graphics. This stream then passes to [[CTIA and GTIA|GTIA]] which applies the playfield colors and incorporates Player/Missile graphics ([[sprite (computer graphics)|sprite]]s) for final output to a TV or composite monitor. Once the display list is set up, the display is generated without any CPU intervention.

There are 15 character and bitmap modes. In low-resolution modes, 2 or 4 colors per display line can be set. In high-resolution mode, one color can be set per line, but the luminance values of the foreground and background can be adjusted. High resolution bitmap mode (320x192 graphics) produces NTSC [[composite artifact colors]]; these colors do not occur on PAL machines.

For text modes, the [[character set]] data is pointed to by a register. It defaults to an address in ROM, but if pointed to RAM then a programmer can create custom characters. Depending on the text mode, this data can be on any 1K or 512 byte boundary. Additional registers flip all characters upside down and toggle inverse video.

[[File:Atari8.png|thumb|A [[Moiré pattern]] in 320 horizontal pixel graphics mode creates [[artifact colors]] from displaying hi-res pixels which are half the size of the NTSC color clock.]]

The [[ANTIC]] chip allows a variety of Playfield modes and widths, and the original Atari Operating System included with the Atari 800/400 computers provides easy access to a subset of these graphics modes. These are exposed to users through Atari BASIC via the "GRAPHICS" command and to some other languages via similar system calls. The later version of the OS used in the XL/XE computers added support for most of these "missing" graphics modes.

ANTIC text modes support soft, redefineable character sets. ANTIC has four different methods of glyph rendering related to the text modes: Normal, Descenders, Single color character matrix, and Multiple colors per character matrix.

The ANTIC chip uses a display list and other settings to create these modes. Any graphics mode in the default [[CTIA and GTIA|CTIA/GTIA]] color interpretation can be freely mixed without CPU intervention by changing instructions in the display list.

The actual ANTIC screen geometry is not fixed. The hardware can be directed to display a narrow Playfield (128 color clocks/256 hi-res pixels wide), the normal width Playfield (160 color clocks/320 hi-res pixels wide), and a wide, overscan Playfield (192 color clocks/384 hi-res pixels wide) by setting a register value. The operating system's default height for creating graphics modes is 192 scan lines, and ANTIC can display vertical overscan up to 240 TV scan lines tall by creating a custom display list.

The display list capabilities provide [[ANTIC#Scrolling|horizontal and vertical coarse scrolling]] requiring minimal CPU direction. Furthermore, the ANTIC hardware supports horizontal and vertical fine scrolling—shifting the display of screen data incrementally by single pixels (color clocks) horizontally and single scan lines vertically.

The system CPU clock and video hardware are synchronized to one-half the NTSC clock frequency. Consequently, the pixel output of all display modes is based on the size of the NTSC color clock which is the minimum size needed to guarantee correct and consistent color regardless of the pixel location on the screen. The fundamental accuracy of the pixel color output allows horizontal fine scrolling without color "strobing"—unsightly hue changes in pixels based on horizontal position caused when signal timing does not provide the TV/monitor hardware adequate time to reach the correct color.

=== CTIA/GTIA ===

The [[CTIA and GTIA|Color Television Interface Adaptor]]<ref name="service-manual-name-2">{{cite book|title=Atari Home Computer Field Service Manual - 400/800|section=I. Theory of Operation|publisher=Atari, Inc.|url=http://www.digitpress.com/library/techdocs/Atari_400-800_Service_Manual.pdf|access-date=September 10, 2010|pages=1–10}}</ref> (CTIA) is the graphics chip originally used in the Atari 400 and 800. It is the successor to the [[Television Interface Adaptor|TIA]] chip of the 1977 Atari VCS. According to Joe Decuir, George McLeod designed the CTIA in 1977. It was replaced with the [[CTIA and GTIA|Graphic Television Interface Adaptor]]<ref name="service-manual-name-2"/> (GTIA) in later revisions of the 400 and 800 and all later 8-bit models. GTIA, also designed by McLeod, adds three new playfield graphics modes to ANTIC which enable more colors.{{sfn|Current|2023|loc=1.12) What are SALLY, ANTIC, CTIA/GTIA/FGTIA, POKEY, and FREDDIE?}}

The CTIA/GTIA receives Playfield graphics information from ANTIC and applies colors to the pixels from a 128 or 256 color palette depending on the color interpretation mode in effect. CTIA/GTIA controls Player/Missile Graphics ([[sprite (computer graphics)|sprites]]) including collision detection between players, missiles, and the playfield; display priority for objects; and color/luminance control of all displayed objects. CTIA/GTIA outputs separate digital luminance and chroma signals, which are mixed to form an analog composite video signal.

CTIA/GTIA reads the joystick triggers and the Option, Select and Start keys, and controls the keyboard speaker in the Atari 400 and 800. In later computer models the audio output for the keyboard speaker is mixed with the audio out for transmission to the TV/video monitor.

=== POKEY ===

[[POKEY]] is a custom chip used for reading the keyboard, paddles, generating sound and serial communications, commands and IRQs, plus (in conjunction with the [[Peripheral Interface Adapter]] chip with two 8-bit bidirectional ports<ref>Rockwell 6520, Doc# 29651N30</ref>) controlling the 4 joystick movements on the 400 and 800 models, and later RAM banks or ROM (OS/BASIC/Self-test) enables for XL/XE lines.<ref>Mapping The Atari, Ian Chadwick and Atari 130XE owner's manual</ref> It provides timers, a [[Random number generation|random number generator]] for generating acoustic [[noise]] and random numbers, and [[maskable interrupt]]s. POKEY has four semi-independent audio channels, each with its own frequency, noise and volume control. Each 8-bit channel has its own audio control register which select the noise content and volume. For higher sound frequency resolution (quality), two of the audio channels can be combined for more accurate sound (frequency can be defined with 16-bit value instead of usual 8-bit). The name POKEY comes from the words "POtentiometer" and "KEYboard", which are two of the I/O devices that POKEY interfaces with (the potentiometer is the mechanism used by the [[Paddle (game controller)|paddle]]). The POKEY chip—and its dual- and quad-core versions—was used in many Atari coin-op arcade machines of the 1980s, including ''[[Centipede (video game)|Centipede]]'' and ''[[Millipede (video game)|Millipede]]'',<ref>[http://www.brasington.org/arcade/cm/trouble.shtml Multipede—Trouble shooting guide], Braze Technologies</ref> ''[[Missile Command]]'', ''[[Asteroids Deluxe]]'', ''[[Major Havoc]]'', and ''[[Star Wars: Return of the Jedi (video game)|Return of the Jedi]]''.

=== Models ===

Atari, Inc. shipped three updated versions of the 400/800 using the same chipset and with a different case aesthetic: the short-lived 1200XL, then the 600XL and 800XL. Numerous other, wide-ranging projects to develop successors to the 8-bit line were cancelled. After the re-establishment of Atari as Atari Corporation, three more systems were released using largely the same technology as earlier machines: the 65XE and 128 KB 130XE in 1985, and finally the game console inspired [[Atari XEGS]] in 1987.

* 400 and 800 (1979)&nbsp;– original machines in beige cases. Both have 4 joystick ports below the keyboard and a cartridge slot covered by a door on the top of the machine. The 400 has a [[membrane keyboard]]. The 800 has full-travel keys, a second, rarely used, cartridge slot, and monitor output. Both have expandable memory (up to 48&nbsp;KB); the RAM slots are easily accessible in the 800. Later [[PAL]] versions have the 6502C processor.
* 1200XL (1983)&nbsp;– new aluminum and smoked plastic case. Includes 64&nbsp;KB of RAM, two joystick ports, a Help key, and four function keys. Some older software was incompatible with the new OS. Starting with the 1200XL, the single cartridge slot is on the side of the case, and there are only 2 joystick ports.
* 600XL and 800XL (1983)&nbsp;– the 600XL has 16&nbsp;KB of memory and PAL versions have a monitor port. The 800XL has 64&nbsp;KB and monitor output. Both have built-in BASIC and a [[Parallel Bus Interface (PBI)]] expansion port. The last produced PAL units contain the [[Atari FREDDIE]] chip and Atari BASIC revision C.
* 65XE and 130XE (1985)&nbsp;– the 65XE has 64&nbsp;KB of RAM. The 130XE has 128&nbsp;KB of bank-switched RAM and an [[Enhanced Cartridge Interface (ECI)]] instead of a PBI. The first revisions of the 65XE have no ECI or PBI, and the later ones contain the ECI. The 65XE was rebranded as the as 800XE in [[Central Europe]] due to the local popularity of the 800XL.{{sfn|Current|2023|loc=1.10) What is the Atari 800XE?}}<ref>{{cite web |title=Atari 800XE |url=https://gury.atari8.info/tech_atari800xe.php |website=Atari8.info |archive-url=https://web.archive.org/web/20140818010334/http://gury.atari8.info/tech_atari800xe.php |archive-date=18 August 2014}}</ref>
* XE Game System (1987)&nbsp;– a 65XE styled as a game console. The basic version of the system shipped without the detachable keyboard. With the keyboard it operates just like other Atari 8-bit computer models. The cartridge slot is on the top, like other consoles.

===Production timeline===
<timeline>
ImageSize = width:800 height:auto barincrement:25
PlotArea  = left:115 bottom:110 top:20 right:10
Alignbars = justify
DateFormat= mm/dd/yyyy
Period    = from:01/01/1979 till:06/30/1992
TimeAxis  = orientation:horizontal format:yyyy
Legend    = orientation:vertical position:bottom columns:4
ScaleMajor= increment:1 start:1979
ScaleMinor= increment:2 start:1979

Colors =
  id:400_Line       value:green         legend:400_&_800_Line
  id:XE_Line        value:blue  legend:XE_Line
  id:XL_Line      value:orange      legend:XL_Line
  id:Lines       value:black       legend:Vertical_lines_are_Product_Announcements
  id:XEGS    value:lavender      legend:XEGS

LineData =
  at:01/05/1979 color:green layer:back
  at:12/13/1982 color:orange layer:back
  at:06/10/1983 color:orange layer:back
  at:01/05/1985 color:blue layer:back
  at:01/05/1987 color:lavender layer:back
  at:01/01/1992 color:black layer:back

BarData =
  bar:400 text:"400 & 800"
  bar:5200 text:"5200"
  bar:1200XL text:"1200XL"
  bar:600XL text:"600XL"
  bar:800XL text:"800XL"
  bar:65XE text:"65XE"
  bar:130XE text:"130XE"
  bar:800XE text:"800XE"
  bar:XEGS text:"XEGS"

PlotData =
  width:10 textcolor:black align:left anchor:from shift:(10,-4)
  bar:400 from:06/05/1979 till:05/01/1983 color:400_Line
  bar:5200 from:11/01/1982 till:05/21/1984 color:400_Line
  bar:1200XL from:03/01/1983 till:07/01/1983 color:XL_Line
  bar:600XL from:07/01/1983 till:07/15/1984 color:XL_Line
  bar:800XL from:07/01/1983 till:02/14/1985 color:XL_Line
  bar:65XE from:05/05/1985 till:06/02/1991 color:XE_Line
  bar:130XE from:01/05/1985 till:02/02/1991 color:XE_Line
  bar:800XE from:05/05/1987 till:01/01/1992 color:XE_Line
  bar:XEGS from:08/05/1987 till:02/14/1991 color:XEGS

  width:3 textcolor:black align:left anchor:from shift:(10,-4)
</timeline>

The production timeline is from 1979 to 1987.{{sfn|Current|2023|loc=1.10) What is the Atari 800XE?}}<ref>{{cite news|url=http://pctimeline.info/comp1978.htm|title=Chronology of Personal Computers|date=April 3, 2014|access-date=February 5, 2015|author=Polsson, Ken|pages=1978|archive-url=https://web.archive.org/web/20150912005639/http://pctimeline.info/comp1978.htm|archive-date=September 12, 2015|url-status=dead}}</ref>

=== Prototypes and vaporware ===
{{unreferenced section|date=July 2023}}

* 1400XL: similar to the 1200XL but with a PBI, FREDDIE chip, built-in modem and a [[Votrax]] SC-01 speech synthesis chip. Cancelled.
* 1450XLD: a 1400XL with built-in {{frac|5|1|4}}″ disk drive and expansion bay for a second {{frac|5|1|4}}″ disk drive. Code named ''Dynasty''. Made it to pre-production, but was abandoned by Tramiel.
* 1600XL: codenamed ''Shakti'', this was dual-processor system with 6502 and [[Intel 80186|80186]] processors and two built-in {{frac|5|1|4}}″ floppy disk drives.<ref>{{Cite web |url=http://www.atarimuseum.com/computers/8BITS/XL/1600xl/1600xl.html |title=1600XL information |access-date=April 14, 2008 |archive-date=September 13, 2011 |archive-url=https://wayback.archive-it.org/all/20110913014906/http://www.atarimuseum.com/computers/8BITS/XL/1600xl/1600xl.html |url-status=dead }}</ref>
* 1850XL: codenamed ''Mickey'', this was to use the "Lorraine" (aka "[[Amiga]]") custom graphics chips
* 65XEM: 65XE with AMY sound synthesis chip. Cancelled.
* 65XEP: "portable" 65XE with {{frac|3|1|2}}" disk drive, 5" green [[Cathode-ray tube|CRT]] and battery pack.

==Peripherals==
{{Main|Atari 8-bit computer peripherals}}
[[File:Atari 1020 plotter.jpg|thumb|[[Atari 1020]] four-color [[plotter]]]]

During the lifetime of the 8-bit series, Atari released a large number of peripherals including cassette tape drives, 5.25-inch floppy drives, printers, modems, a touch tablet, and an 80-column display module.

Atari's peripherals use the proprietary [[Atari SIO]] port, which allows them to be [[daisy chain (electrical engineering)|daisy chain]]ed together. A primary goal of the Atari computer design was user-friendliness which was assisted by the SIO bus. Since only one kind of connector plug is used for all devices the Atari computer was easy for novice users to expand. Atari SIO devices use an early form of plug-n-play. Peripherals on the bus have their own IDs, and can deliver downloadable drivers to the Atari computer during the boot process. The additional electronics in these peripherals made them cost more than the equivalent "dumb" devices used by other systems of the era.

==Software==
{{Main|Atari 8-bit computer software}}

Atari did not initially disclose technical information for its computers, except to software developers who [[non-disclosure agreement|agreed to keep it secret]], possibly to increase its own software sales.{{r|nelson198006}} Cartridge software was so rare at first that ''InfoWorld'' joked in 1980 that Atari owners might have considered turning the slot "into a fancy ashtray". The magazine advised them to "clear out those cobwebs" for Atari's ''[[Star Raiders]]'',<ref>{{cite news|title=Star Raiders from Atari|work=InfoWorld|date=July 7, 1980|author=Cole, David C.|pages=13}}</ref> which became the platform's [[killer app]], akin to [[VisiCalc]] for the Apple II in its ability to persuade customers to buy the computer.<ref>{{cite magazine|url=https://archive.org/stream/byte-magazine-1981-05/1981_05_BYTE_06-05_Software_Piracy#page/n107/mode/2up|title=Star Raiders|magazine=BYTE|date=May 1981|author=Williams, Gregg|pages=106}}</ref>{{sfn|Goldberg|Vendel|2012|p=526}}

[[Chris Crawford (game designer)|Chris Crawford]] and others at Atari published detailed technical information in ''[[De Re Atari]]''.<ref>{{cite news |url=https://archive.org/stream/Atari_Program_Exchange_catalog_Fall_1983#page/n35/mode/2up|title=The quarterly APX contest / APX: Programs by our users...for our users / Publications / Hardware|work=APX Product Catalog|date=Fall 1983 |access-date=July 29, 2014|pages=34, 72}}</ref> In 1982, Atari published both the ''Atari Home Computer System Hardware Manual''<ref>{{cite book|title=Atari Home Computer System Hardware Manual|year=1982|publisher=Atari, Inc.|url=http://www.atarimania.com/documents/atari-400-800-hardware-manual.pdf}}</ref> and an annotated source listing of the operating system. These resources resulted in many books and articles about programming the computer's custom hardware.

Because of graphics superior to those of the Apple II<ref>{{cite news|url=https://archive.org/stream/byte-magazine-1982-07/1982_07_BYTE_07-07_Computers_in_the_Arts_and_Sciences#page/n381/mode/2up|title=Computers for Humanity|work=BYTE|date=July 1982|author=Pournelle, Jerry|pages=392}}</ref> and Atari's home-oriented marketing, games dominated its software library. A 1984 compendium of reviews used 198 pages for games compared to 167 for all others.<ref>{{cite book|url=https://archive.org/stream/Atari_Software_1984#page/n3/mode/2up|title=The Addison-Wesley Book of Atari Software|publisher=Addison-Wesley|year=1984|pages=TOC,12,210|isbn=0-201-16454-X|editor1=Stanton, Jeffrey|editor2=Wells, Robert P.|editor3=Rochowansky, Sandra|editor4=Mellid, Michael}}</ref>

===Built-in operating system===
[[File:Atari Computer Memo Pad.png|thumb|When no other program is available, the Atari 400 and 800 boot into Memo Pad: a fullscreen text editor which can't save or load.]]

The Atari 8-bit computers have an operating system built into the [[read-only memory|ROM]]. The Atari 400 and 800 have two versions:
*OS Rev. A – 10 KB ROM (3 chips) early machines
*OS Rev. B – 10 KB ROM (3 chips) most common

The XL/XE all have OS revisions, which created compatibility issues with certain software. Atari responded with the Translator Disk, a floppy disk which loads the older 400 and 800 Rev. 'B' or Rev. 'A' OS into the XL/XE computers.
*OS Rev. 10 – 16 KB ROM (2 chips) for 1200XL Rev A
*OS Rev. 11 – 16 KB ROM (2 chips) for 1200XL Rev B (bug fixes)
*OS Rev. 1 – 16 KB ROM for 600XL
*OS Rev. 2 – 16 KB ROM for 800XL
*OS Rev. 3 – 16 KB ROM for 800XE/130XE
*OS Rev. 4 – 32 KB ROM (16 KB OS + 8 KB BASIC + 8 KB Missile Command) for XEGS

The XL/XE models that followed the 1200XL also have the [[Atari BASIC]] ROM built-in, which can be disabled at startup by holding down the silver <code>OPTION</code> key. Originally this was revision B, which has some serious bugs. Later models have revision C.

===Disk Operating System===
{{Main|Atari DOS}}

The standard Atari OS only contains low-level routines for accessing [[floppy disk]] drives. An extra layer, a [[disk operating system]], is required to assist in organizing [[file system]]-level disk access. [[Atari DOS]] has to be booted from floppy disk at every power-on or reset. Atari DOS is entirely menu-driven.

*DOS 1.0
*DOS 2.0S – Improved over DOS 1.0; became the standard for the 810 disk drive.
*DOS 3.0 – Came with 1050 drive. Uses a different disk format which is incompatible with DOS 2.0, making it unpopular.
*DOS 2.5 – Replaced DOS 3.0 with later 1050s. Functionally identical to DOS 2.0S, but able to read and write [[Atari DOS#Disk formats|enhanced density]] disks.
*DOS XE – Designed for the [[Atari XF551]] double-density drive.

[[Atari DOS#Third-party DOS programs|Third-party replacement DOSes]] were also available.

== Legacy ==

At the beginning of 1992, Atari Corporation officially [[End-of-life product|dropped all remaining support]] for all the 8-bit computers.<ref name="droppedsupport"/> In 2006, Curt Vendel, who designed the [[Atari Flashback]],<ref>{{cite web|url=http://www.ign.com/articles/2004/12/15/atari-flashback|title=Atari Flashback|website=[[IGN]]|date=December 15, 2015|access-date=September 23, 2019}}</ref> claimed that Atari released the 8-bit chipset into the [[public domain]].<ref>[http://atariage.com/forums/topic/74783-fb3/page-17#entry1035425 FB3...] by Curt Vendel on atariage.com "Atari released the Atari 8bit chipset into PD for me several years ago, so any FB3 project at this point could very well turn into a PD or individual released project/product"</ref> There is agreement in the community that Atari authorized the distribution of the Atari 800's ROM with the Xformer 2.5 [[emulator]], which makes the ROM legally available today as [[freeware]].<ref>{{Cite web|url=http://atariarea.krap.pl/PLus/index_us.htm|title=Atari800Win PLus - The Atari 8-bit Emulator: News|website=atariarea.krap.pl}}</ref><ref>[https://groups.google.com/forum/#!topic/comp.sys.mac.apps/_E74sEbiXTU How to Get Roms for "Rainbow" (Atari XL Emulator)! The answer] on groups.google.com (1995)</ref>

On March 29, 2024, [[Atari SA]] and Retro Games Ltd, via the distributor [[Plaion]], released the Atari 400 Mini, at a cost of £99.99 (€119.99 / $119.99). It is a half-sized scale-model [[microconsole]] emulation of the Atari 400, preloaded with 25 games. It comes with an updated [[Atari CX40 joystick]] with additional buttons.<ref>{{cite web | url =https://presse.plaion.com/AN-ICON-RETURNS-RETRO-GAMES-LTD-AND-PLAION-ANNOUNCE-MINI-RECREATION-OF | title = An Icon Returns: Retro Games Ltd. and Plaion Announce Mini Recreation of the Atari 400™ Press Server|website=presse.plaion.com | date = January 11, 2024}}</ref><ref>{{cite web | url = https://www.theverge.com/24113699/atari-400-mini-hands-on | title = The Atari 400 Mini is a cute little slice of video game history | first = Andrew | last= Webster | date = March 30, 2024 | accessdate = March 30, 2024 | work = [[The Verge]] }}</ref>

==References==
{{Reflist}}

== Bibliography ==

* {{ cite web | url = http://www.atarimuseum.com/computers/8BITS/400800/ATARI800/A800.html | title = The Atari 800 Personal Computer System | archiveurl = https://archive.today/20121208194608/http://www.atarimuseum.com/computers/8BITS/400800/ATARI800/A800.html | archivedate=December 8, 2012 | publisher = Atari Museum |accessdate = November 13, 2008 }}
* {{ cite book | last1 = Goldberg | first1 = Marty | last2 = Vendel | first2 = Curt | title = Atari Inc: Business is Fun | date = 2012 | url = https://archive.org/details/atariincbusiness0000gold | url-access = registration | publisher = Syzygy Press | isbn = 9780985597405 }}
* {{ cite book |title=Hackers: Heroes of the Computer Revolution |year=1984 |isbn=0-385-19195-2|last=Levy |first=Steven |publisher=Doubleday }}
* {{ cite interview | title = ANTIC Interview 32 - Al Alcorn, Atari Employee #3 | date = 12 April 2015 | last = Alcorn | first = Al | url = http://ataripodcast.libsyn.com/antic-interview-32-al-alcorn-atari-employee-3 | website = Antic | interviewer = Randy Kindig }}
* {{ cite web |last=Current |first=Michael D. |title=Atari 8-Bit Computers: Frequently Asked Questions |date=May 29, 2023 |orig-date=1992 |url=https://mcurrent.name/atari-8-bit/faq.txt |access-date=October 10, 2023 }}

== External links ==

* [http://www.atarimuseum.com/computers/8BITS/400800/peripherals/index.html Atari 400/800 Peripherals] {{Webarchive|url=https://web.archive.org/web/20141211090247/http://www.atarimuseum.com/computers/8BITS/400800/peripherals/index.html |date=December 11, 2014}}
* [https://www.gamedeveloper.com/game-platforms/a-history-of-gaming-platforms-atari-8-bit-computers "A History of Gaming Platforms: Atari 8-bit Computers"] at Gamasutra
* [http://www.atarimuseum.com/computers/8BITS/XL/XL-Pages/xl-range-main.htm Atari XL Series Systems & Prototypes] {{Webarchive|url=https://web.archive.org/web/20190702201614/http://www.atarimuseum.com/computers/8BITS/XL/XL-Pages/xl-range-main.htm |date=July 2, 2019}}
* [http://www.xmission.com/~trevin/atari/atari.html Technical chipset information]

{{Atari hardware}}
{{Authority control}}

[[Category:Atari 8-bit computers| ]]
[[Category:6502-based home computers]]
[[Category:Home computers]]
[[Category:Computer-related introductions in 1979]]