Hardware Catalog (in progress)

Here you will find basic information about ATARI hardware.

The specifications, particularly regarding memory and the number of colors/sound that can be displayed simultaneously, refer to the factory settings. Through clever programming, significantly more colors can be displayed on the screen at the same time (without any hardware modifications!). Sound output can be programmed to play samples, for example.

This section initially covers the computers themselves and will be expanded gradually (floppy drives, printers, accessories, third-party manufacturers). Some features are common to all computers. Listing these individually for each computer would unnecessarily bloat the articles, so I’m summarizing them here. If a computer has specific characteristics, these will be described in the corresponding article.

Throughout the entire production period of the 8-bit series (1979 to 1992), ATARI used virtually the same custom ICs. As a result, the “capabilities” across the three series are virtually identical. Nevertheless, there are ongoing improvements in sound and graphics made possible by new programming techniques.

POKEY (IC) The Potentiometer and Keyboard Controller is, as the name suggests, responsible for polling the keyboard and the analog inputs of the joystick ports. Its responsibilities also include sound generation (four channels, each with 3.5 octaves) and communication with peripherals via the SIO bus.

ANTIC (IC) The Alphanumeric Television Interface Controller has its own instruction set, which it uses to build the screen without the CPU. It accesses memory directly via DMA. The program for the ANTIC, known as the Display List (DL), runs independently of the actual program being processed by the CPU. By modifying the DL, custom graphics modes can be created.

CTIA / GTIA (IC) The Color (or Graphics) Television Interface Adapter generates the actual television image based on data from the ANTIC. It is responsible for the player and missile graphics: There are four players and four missiles (comparable to sprites) that can move over the background independently of it. It polls the fire buttons and function keys and generates the keyboard click—this “sound channel” can also be used for custom sounds through clever programming. The first ATARI 400/800 models used the CTIA, which was later replaced by the GTIA. The GTIA expanded the color palette from 128 to 256 colors and provided the extended graphics modes 9–11. ATARI BASIC (available as a plug-in module for the ATARI 400/800 and 1200XL; built-in on all other XL, XE, and XEGS models) provides the following 16 graphics modes (values in parentheses apply when the text window is displayed at the bottom of the screen):

  • GRAPHICS 0: 40 x 24 characters / 2 colors (normal text, 992 bytes)
  • GRAPHICS 1: 20 x 24 (20) characters / 5 colors (large text, 672 bytes)
  • GRAPHICS 2: 20 x 12 (10) characters / 5 colors (large text, 420 bytes)
  • GRAPHICS 3: 40 x 24 (20) pixels / 4 colors (bitmap, 432 bytes)
  • GRAPHICS 4: 80 x 48 (40) pixels / 2 colors (bitmap, 696 bytes)
  • GRAPHICS 5: 80 x 48 (40) pixels / 4 colors (bitmap, 1176 bytes)
  • GRAPHICS 6: 160 x 96 (90) pixels / 2 colors (bitmap, 2184 bytes)
  • GRAPHICS 7: 160 x 96 (90) pixels / 4 colors (bitmap, 8138 bytes)
  • GRAPHICS 8: 320 x 192 (160) pixels / 1 color in 16 shades (bitmap, 8138 bytes)
  • GRAPHICS 9: 80 x 192 pixels / 1 color in 16 shades (GTIA mode, 8138 bytes)
  • GRAPHICS 10: 80 x 192 pixels / 9 colors (GTIA mode, 8138 bytes)
  • GRAPHICS 11: 80 x 192 pixels / 16 colors (GTIA mode, 8138 bytes)
  • GRAPHICS 12: 40 x 24 (20) character text graphics / 5 colors (text, 1152 bytes)
  • GRAPHICS 13: 40 x 12 (10) character text graphics / 5 colors (text, 660 bytes)
  • GRAPHICS 14: 160 x 192 (160) pixels / 2 colors (bitmap, 4296 bytes)
  • GRAPHICS 15: 160 x 192 (160) pixels / 4 colors (bitmap, 8138 bytes)

In addition, the ATARI hardware offers the ability to redefine both the graphics mode and the color registers in every line, making the display very flexible since you are not limited to the predefined graphics modes and can increase the number of colors that can be displayed simultaneously across the entire screen.

SALLY (IC) Inside the 8-bit ATARI runs a 6502A (400/800) or a 6502C (all others). The “C” type was equipped with an additional pin (HALT) for ATARI and should not be confused with the 65C02.

SIO BUS (I/O) The Serial Input/Output bus can be considered a precursor to USB. In addition to original accessories such as floppy drives, Datasettes, and printers, it also connects MIDI interfaces or modern mass storage devices using SD cards or USB flash drives as media. The devices are connected in parallel on the bus and are addressed via their own addresses.

Joystick Ports (I/O) For each port, 4 bits for direction, 1 fire button, and two analog values (paddles) can be read. Data can also be output via the 4 direction bits, allowing a printer, an 80-character card, or other hardware to be controlled via the joystick ports.

RF Output (O) The antenna output is on VHF channel 3 or 4; on some devices, it is also switchable (NTSC/SECAM?).

Monitor Jack (O) A monitor can be connected to all computers (except the ATARI 400). A 5-pin DIN jack is used, from which the video signal is available as F-Bas (composite video) and the audio signal can be picked up. Only the XEGS uses two RCA jacks for this purpose.

Power Supply (I) The 400/800 and the 1200XL are powered via a barrel plug with 9V AC. All XL/XE models and the XEGS (XE GameSystem) are powered via a 7-pin DIN plug with 5V DC. Connecting a Commodore power supply with an identical plug is fatal! The accessories are generally powered by an external (plug-in) power supply that provides AC voltage. Devices with lower power requirements, such as the Datasette or MIDI interface, are powered via the SIO bus. A few devices have a built-in power supply.

On the right, after the computers, you will find a list of ATARI power supplies and the devices they are compatible with.

Pages/images are still missing for:

  • ATARI Super SALT Controller
  • ATARI 1055 (3.5" Disk, Prototype)
  • CX75 (light pen)
  • XC1411 (monitor)
  • XTC201 (color printer)
  • XDM121 (dot matrix printer)
  • Mindlink