Editing Atari Jaguar (section)

==Technical specifications==
From the Jaguar Software Reference manual, page 1:<ref name=atarimanual>{{cite book | author = Atari Corp. | title = Jaguar Software Reference Manual - Version 2.4 | publisher = Atari Corp. | year = 1995 | url = http://www.hillsoftware.com/files/atari/jaguar/jag_v8.pdf | access-date = November 26, 2012 | archive-url = https://web.archive.org/web/20130315005843/http://www.hillsoftware.com/files/atari/jaguar/jag_v8.pdf | archive-date = March 15, 2013 | url-status = dead }}</ref>

{{blockquote|Jaguar is a custom chip set primarily intended to be the heart of a very high-performance games/leisure computer. It may also be used as a graphics accelerator in more complex systems, and applied to workstation and business uses. As well as a general purpose CPU, Jaguar contains four processing units. These are the Object Processor, Graphics Processor, Blitter, and Digital Sound Processor. Jaguar provides these blocks with a 64-bit data path to external memory devices, and is capable of a very high data transfer rate into external dynamic RAM.}}

[[File:Atari-Jaguar-Motherboard-Flat.jpg|thumb|The Jaguar's multi-chip architecture was difficult to use for most contemporary developers.]]
Design specs for the console allude to the GPU or DSP being capable of acting as a CPU, leaving the Motorola 68000 to read controller inputs. Atari's Leonard Tramiel also specifically suggested that the 68000 not be used by developers. In practice, however, many developers use the Motorola 68000 to drive gameplay logic due to the greater developer familiarity of the 68000 and the adequacy of the 68000 for certain types of games. Most critically, a flaw in the [[memory controller]] means that certain obscure conventions must be followed for the RISC chips to be able to execute code from [[Random-access memory|RAM]].<ref name="Owl">{{cite web |url=http://atariowlproject.blogspot.com/2009/10/atari-jaguar-homebrew-whats-this-lay.html |title=What's this "Lay off the 68k" and "GPU in Main" Malarkey? (TECHNICAL) |author=Joe Venor |publisher=The Owl Project |date=2009 |access-date=February 18, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612142447/http://atariowlproject.blogspot.com/2009/10/atari-jaguar-homebrew-whats-this-lay.html |url-status=live }}{{better source needed|date=October 2021}}</ref>

The system was notoriously difficult to program for, because its multi-processor design is complex,  development tools were released in an unfinished state, and the hardware had crippling bugs.<ref>[https://www.retrogamer.net/profiles/hardware/atari-jaguar-2/ ATARI JAGUAR] {{Webarchive|url=https://web.archive.org/web/20150906051454/http://www.retrogamer.net/profiles/hardware/atari-jaguar-2/ |date=September 6, 2015 }} by Retro Gamer Team, November 27, 2014</ref>

===Processors===
* Tom chip, 26.59&nbsp;[[megahertz|MHz]]
** [[Graphics processing unit]] (GPU) – 32-[[bit]] [[reduced instruction set computing|RISC]] architecture, 4 [[kilobyte|KB]] internal RAM, all graphical effects are software-based, with additional instructions intended for 3D operations
** Object Processor – 64-bit fixed-function video processor, converts display lists to video output at scan time.
** [[Blitter]] – 64-bit high speed logic operations, [[z-buffering]] and [[Gouraud shading]], with 64-bit internal registers.
** [[Dynamic random-access memory|DRAM]] controller, 8-, 16-, 32- and 64-bit memory management
* Jerry chip, 26.59&nbsp;[[megahertz|MHz]]
** Digital Signal Processor – 32-[[bit]] [[Reduced instruction set computing|RISC]] architecture, 8&nbsp;KB internal RAM
*** Similar [[reduced instruction set computing|RISC]] core as the [[graphics processing unit|GPU]], additional instructions intended for audio operations
** CD-quality sound (16-bit stereo)
*** Number of sound channels limited by software
*** Two DACs (stereo) convert digital data to analog sound signals
*** Full [[stereophonic sound|stereo]] capabilities
** [[Sample-based synthesis|Wavetable synthesis]] and AM synthesis
** A clock control block, incorporating timers, and a [[universal asynchronous receiver-transmitter|UART]]
** Joystick control
* [[Motorola 68000]] - system processor "used as a manager".<ref>Atari Jaguar Software Reference Manual, Atari Corp. 1995, Pg 2</ref>
** General purpose 16-/32-bit control processor, 13.295&nbsp;[[megahertz|MHz]]

===Other features===
[[File:Atari-Jaguar-Console-Back.jpg|thumb|The inputs and outputs of an [[NTSC]] Jaguar]]
* [[Random-access memory|RAM]]: 2&nbsp;[[Megabyte|MB]] on a 64-bit bus using 4 16-bit fast-page-mode DRAMs (80&nbsp;[[Nanosecond|ns]])<ref>[http://untergrund.net/users/ggn/Atari%20HQ/Documents/Atari/Jaguar/Eco1686.pdf Atari Jaguar Order]{{Dead link|date=January 2022 |bot=InternetArchiveBot |fix-attempted=yes }}, [[Atari]], 1994</ref>
* Storage: [[ROM cartridge]]s – up to 6&nbsp;MB
* DSP-port (JagLink)
* Monitor-port (composite/S-Video/RGB)
* Antenna-port (UHF/VHF) - fixed at 591&nbsp;MHz in Europe; not present on French model
* Support for ComLynx [[input/output|I/O]]
* NTSC/PAL machines can be identified by their power LED colour, Red: NTSC; Green: PAL.

===COJAG arcade games===
{{Main|Atari CoJag}}
[[Atari Games]] licensed the Jaguar's chipset for use in its arcade games. The system, named CoJag (for "Coin-Op Jaguar"), replaced the [[Motorola 68000|68000]] with a [[Motorola 68020|68020]] or [[MIPS Technologies|MIPS]] [[R3000]]-based CPU (depending on the board version), added more RAM, a full 64-bit wide ROM bus (Jaguar ROM bus is 32-bit), and optionally a hard drive (some games such as ''Freeze'' are ROM only). It runs the lightgun games ''[[Area 51 (1995 video game)|Area 51]]'' and ''[[Maximum Force]]'', which were released as dedicated cabinets or as the ''Area 51'' and ''Maximum Force'' combo machine. Other games were developed but never released: ''3 On 3 Basketball'', ''Fishin' Frenzy'', ''Freeze'', and ''Vicious Circle''.