Editing Atari XE Game System

{{Infobox computer
| name         = Atari XE Game System
| image        = [[File:Atari XEGS with keyboard.jpg|300px]]
| caption      = Atari XEGS with detachable keyboard
| manufacturer = Atari Corporation
| type         = Home Video Game Console / Home Computer
| release date = Late 1987
| discontinued = December 1991
| price        = US$149.95 (deluxe set); US$79.95 (basic set)
| cpu          = MOS Technology 6502C (SALLY) @ 1.79 MHz (NTSC) / 1.77 MHz (PAL)
| memory       = 64 KB RAM, 24 KB ROM (OS, BASIC, Missile Command)
| storage      = ROM cartridge; SIO peripherals (disk, cassette) with keyboard
| display      = 320×192 pixels max, 16 colours from 256-colour palette (ANTIC/GTIA)
| sound        = POKEY: 4 voices, 8-bit
| os           = Atari OS (Rev. 4), Atari BASIC Rev. C (in keyboard ROM)
| predecessor  = [[Atari 7800]]
| successor    = [[Atari Jaguar]] (Atari Panther, cancelled)
| model        = XEGS (C100417)
}}

The '''Atari XE Game System''' (commonly referred to as the '''XEGS''') is a home video game console and computer hybrid released by [[Atari Corporation]] in late 1987. It is essentially a repackaged '''Atari 65XE''' home computer housed in a console-style enclosure with a detachable keyboard, positioning it as both a gaming console and a fully functional 8-bit computer. The XEGS was the final hardware release in the [[Atari 8-bit computer]] family.

== History and Market Context ==

By 1987, Atari Corporation was competing in the console market with its [[Atari 7800]] against Nintendo's NES and Sega's Master System. Atari conceived the XEGS as a way to leverage its mature 8-bit computer platform—with a library of thousands of existing software titles—while presenting it as a contemporary game console to mass-market retailers.

Atari executives reportedly found that major toy store chains preferred to stock a "fancy new game system" at US$150 rather than the 65XE home computer at US$80. The XEGS was therefore marketed primarily as a gaming device, with computer functionality available via the optional detachable keyboard.

The system was released alongside new game titles including ''Barnyard Blaster'' and ''Bug Hunt'' (both designed for the XG-1 light gun), as well as cartridge ports of older 8-bit titles. '''Missile Command''' was built into the console's ROM and could be played without a cartridge inserted.

Atari discontinued the XEGS along with the rest of its 8-bit product line in December 1991. Approximately 100,000 units were sold.

== Technical Specifications ==

The XEGS is internally identical to the Atari 65XE computer and shares the same custom chipset used across all Atari XE-series machines.

=== Processor ===

The XEGS uses the '''MOS Technology 6502C''' (SALLY) microprocessor, a modified version of the 6502 with additional bus control features required by the Atari architecture. It runs at:
* '''1.79 MHz''' (NTSC systems)
* '''1.77 MHz''' (PAL systems)

The SALLY variant includes a HALT input that allows the ANTIC chip to steal bus cycles for direct memory access (DMA) during display generation.

=== Custom Chipset ===

<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''XEGS Custom Chipset'''
! Chip !! Function !! Package !! Key Features
|-
| '''ANTIC''' (C021697) || Display controller || 40-pin DIP || Generates display list DMA, handles playfield graphics modes 2–15, horizontal/vertical scrolling, display list interrupts (DLI)
|-
| '''GTIA''' (C014805) || Graphics/colour processor || 40-pin DIP || Player/missile (sprite) graphics, colour processing, 16 colours from 256-colour palette, console key inputs (Start/Select/Option)
|-
| '''POKEY''' (C012294) || Sound and I/O || 40-pin DIP || 4-channel audio, keyboard scanning, serial I/O (SIO bus), timer/IRQ generation, paddle input, random number generator
|-
| '''FREDDIE''' (C061991) || Memory controller || 28-pin DIP || DRAM multiplexing and refresh, address bus control, replaces discrete multiplexers used in earlier XL models
|-
| '''PIA''' (6520) || Peripheral interface || 40-pin DIP || Joystick port I/O, peripheral control lines
|-
| '''MMU''' (C061618) || Memory management || 20-pin DIP || Address decoding, bank select, ROM/RAM mapping
|}

=== Memory ===

* '''64 KB DRAM''' — Eight 4464 (64K×4) DRAM chips (unlike the 65XE's eight 4164 chips, the XEGS board uses 4464s in some revisions)
* '''24 KB ROM''' — Operating system (Rev. 4), Atari BASIC Rev. C, and built-in Missile Command game
* ROM is active when the keyboard is attached; without keyboard, only the OS and Missile Command ROMs are mapped

=== Video Output ===

* '''Composite video''' via RCA jack
* '''RF modulated output''' via RCA jack (channel 2/3 switchable)
* Resolution: up to 320×192 pixels (Graphics 8), 384×240 with overscan
* Text: 40 columns × 24 rows
* 16 simultaneous colours from a palette of 256 (128 hues × 8 luminances on NTSC)
* Hardware scrolling, player/missile graphics (sprites)

=== Audio ===

* '''POKEY''' chip provides 4 independent audio channels
* 8-bit resolution per channel
* Frequency range approximately 30 Hz to 56 kHz (audible range)
* Noise generation, high-pass filter capability
* Two channels can be combined for 16-bit resolution

== Physical Design and Ports ==

The XEGS features a wedge-shaped grey console case distinct from the 65XE's computer-style housing. The top panel includes five pastel-coloured membrane buttons: '''Power''', '''Start''', '''Select''', '''Option''', and '''Reset'''.

=== Rear Ports ===

* '''Power input''' — Standard Atari XE/XL power connector (centre-positive 5 V DC)
* '''SIO (Serial I/O) port''' — 13-pin proprietary connector for disk drives, cassette, printers, and modems
* '''Composite video output''' — RCA jack
* '''RF output''' — RCA jack
* '''Channel select switch''' — Channel 2/3 for RF output
* '''Monitor audio output''' — RCA jack

=== Front/Side Ports ===

* '''Two DE-9 joystick ports''' — Compatible with Atari-standard digital joysticks, paddles, and the XG-1 light gun
* '''Cartridge slot''' — Top-loading, accepts all standard Atari 8-bit cartridges
* '''ECI (Enhanced Cartridge Interface)''' — Active active connector for enhanced peripherals

=== Keyboard ===

The XEGS detachable keyboard connects via a proprietary flat ribbon cable and connector on the right side of the console. When attached, the system boots to the Atari BASIC '''READY''' prompt (identical to the 65XE) and can run the full range of Atari 8-bit software including disk-based and cassette-based programs via SIO. Without the keyboard, the system boots directly into Missile Command or a cartridge game.

== Included Accessories ==

The XEGS was sold in two configurations:

* '''Basic set''' — Console and CX40 joystick (grey base variant)
* '''Deluxe set''' — Console, detachable keyboard, CX40 joystick, and XG-1 light gun

The '''XG-1 light gun''' was Atari's first light gun peripheral, also compatible with the [[Atari 7800]] and [[Atari 2600]]. Games supporting the light gun include ''Bug Hunt'' and ''Barnyard Blaster''.

== Software Compatibility ==

The XEGS is fully compatible with the Atari 8-bit software library:
* All standard Atari 8-bit cartridges (400/800/XL/XE format)
* Disk-based software via SIO-connected drives (keyboard required for BASIC loading)
* Cassette-based software (keyboard required)

Some older titles designed for the Atari 400/800 may have minor compatibility issues due to the Rev. 4 OS, which can be resolved by using an older OS ROM.

== PCB and Board Revisions ==

The XEGS mainboard is designated '''C100417''' and exists in at least one revision (Rev. A). The board layout is derived from the 65XE but is redesigned to fit the console-style enclosure and includes provisions for the detachable keyboard connector.

== Gallery ==

<gallery>
File:Atari XEGS with keyboard.jpg|Atari XEGS with keyboard attached
</gallery>

== See Also ==

* [[Atari XE Game System General Maintenance]]
* [[Atari XE Game System Troubleshooting Guide]]
* [[Atari XE Game System Capacitor Replacement Guide]]
* [[Atari 65XE]]
* [[Atari 130XE]]
* [[Atari 7800]]

{{Navbox-AtariVintageComputers}}
[[Category:Atari Systems]]