Atari 520ST

The Atari 520ST introduced Atari’s new 16/32-bit computer family to retail buyers in 1985. Built around an 8 MHz Motorola 68000, it combined colourful bitmap graphics, the mouse-driven GEM desktop and extensive built-in interfaces at a price far below comparable graphical computers.

The original machine used an external power supply and external floppy drive. Early examples loaded TOS from disk, while later production placed the operating system in ROM. Its built-in MIDI ports made the ST family especially influential in music production.

Notable Features

• Combined an 8 MHz Motorola 68000, GEM graphical desktop and extensive built-in interfaces at an unusually low price.
• Offered three display modes, including a sharp 640x400 monochrome mode for productivity software.
• Included MIDI In and Out ports as standard, helping the ST become a fixture in music studios.

Historical Significance

• The 520ST was the first commercially released Atari ST and marked Atari’s return to the home-computer market under Jack Tramiel.
• After a limited initial release, wider retail availability began in July 1985.

Collector’s Notes

• Early machines load TOS from floppy disk; later examples contain TOS in ROM.
• A complete original system includes the external SF354 or SF314 floppy drive, power supply, mouse and an Atari monitor.

Specifications

Technical Information
Name	Atari 520ST
Manufacturer	Atari
Launched	Monday, July 1, 1985
Discontinued	April 1986
Launch Price	US$599 computer; US$799 complete monochrome system
Country	United States
CPU	Motorola MC68000 at 8 MHz
Units Sold
Operating System	Atari TOS with GEM desktop
I/O	MIDI In/Out, RS-232 serial, Centronics parallel, ACSI hard-disk, cartridge, floppy, monitor and two joystick/mouse ports
Keyboard	Integrated 95-key keyboard with numeric keypad and function keys
Storage	External 3.5-inch floppy drive; ACSI hard-disk support
Sound	Yamaha YM2149 three-channel programmable sound generator
Colour Palette	512 colours
Display	320x200 in 16 colours, 640x200 in 4 colours, or 640x400 monochrome
ROM	192KB on later ROM-TOS machines; early systems boot TOS from disk
RAM	512KB
CPU Speed	8 MHz