Editing ANTIC (section)

{{Short description|Computer graphics chip}}
{{About|the Atari 8-bit display chip|the magazine|Antic (magazine)|the surname|Antić|the London pub chain|Antic Collective}}
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{{how-to|date=May 2019}}
{{More citations needed|date=May 2019}}
{{notability|date=February 2023}}
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[[File:ANTIC chip on an Atari 130XE motherboard.jpg|thumb|ANTIC chip on an Atari 130XE motherboard]]

'''Alphanumeric Television Interface Controller'''<ref name="service-manual-name">{{cite book |title=Atari Home Computer Field Service Manual - 400/800 |publisher=Atari, Inc. |type = PDF |pages=1–8}}</ref> ('''ANTIC''') is an [[Large Scale Integration|LSI]] [[ASIC]] dedicated to generating [[2D computer graphics]] to be shown on a [[television]] screen or [[computer monitor|computer display]].

Under the direction of [[Jay Miner]], the chip was designed in 1977–1978 by [[Joseph C. Decuir|Joe Decuir]], Francois Michel, and Steve Smith<ref>{{cite web |url=http://dougneubauer.com/atari/#headnumber3 |title=The Atari Years, by Doug Neubauer. Star Raiders, Solaris and Pokey |last=Neubauer |first=Doug |date=2009-06-20 |work=DougNeubauer.com }}</ref> for the [[Atari 8-bit computers]] first released in 1979. The chip was patented by [[Atari, Inc.]] in 1981.<ref>{{cite patent |country=US |number=4296476  |status=patent |title=Data processing system with programmable graphics generator |gdate=1981-10-20 |fdate=1979-01-08 |inventor=Mayer, Steven T.; [[Jay Miner|Miner, Jay G.]]; Neubauer, Douglas G.; Decuir, Joseph C. | assign1=Atari, Inc.}}</ref>  ANTIC is also used in the 1982 [[Atari 5200]] video game console, which shares most of the same hardware as the 8-bit computers.

For every frame of video, ANTIC reads [[instruction set architecture|instructions]] to define the playfield, or background graphics, then delivers a data stream to the companion [[CTIA and GTIA|CTIA or GTIA]] chip which adds color and overlays [[sprite (computer graphics)|sprite]]s (referred to as "Player/Missile graphics" by Atari). Each ANTIC instruction corresponds to either blank [[scan line]]s or one of 14 graphics modes used for a horizontal band of the display. The height of each band depends on the mode. The instructions comprise a [[display list]], in Atari parlance, which specifies how the entire display is built from a stack of individual modes.

The display list specifies where the data for each row comes from. For character modes, the base address of the character bitmaps is stored in an on-chip register and can be changed. Display list instructions can enable horizontal and vertical fine scrolling and mark that an interrupt should occur. An interrupt allows arbitrary 6502 code to execute, usually to change display-related settings in the middle of a frame.

Atari computer magazine ''[[Antic (magazine)|Antic]]'' was named after the chip.<ref>{{cite journal |last1=Bisson |first1=Gigi |title=Antic then and now. How the Atari community and this magazine grew up together |journal=Antic |date=May 1986 |volume=5 |issue=1 |pages=16–17 |url=https://archive.org/details/1986-05-anticmagazine/page/n15/mode/2up?view=theater |access-date=23 February 2023 |issn=0745-2527}}</ref>