The Atari 520ST
Personal Computer System

    In 1985 Atari Corporation introduced its new 16-bit computer system.   Called the 520ST.   520 being the memory size and ST for Sixteen/Thirty Two bit processor.   The Atari ST originally had its OS delivered on floppy disk since the OS ROM's were not ready for shipping.   The 520ST represents a major step forward in computer design and OS design.   However many rough spots do show through and this most likely is a result of the machine being rushed market to gain a lead on the soon to be release Amiga computer system which was bought by Commodore and the money that Atari had been supplying to Amiga for development to use the technology in the Atari 1850XL computer before the Tramiels bought Atari was paid back.    The ST computer utilized the Digital Research GEM interface for a graphics environment.   (As an interesting note, Apple Computer sued Digital Research for the GEM "Look & Feel" on the PC version and Digital Research was forced to change it, how Apple never sued Atari or Digital for the version used on the Atari ST's.   Perhaps Apple felt that the Atari ST's were not going to be a enough of a threat to merit a lawsuit.)


 
 
 

Technical Specifications

Architecture

Processor
CPU: Motorola 68000 Running at 8 Mhz

Memory
RAM 512K
ROM up to 192K
Cartridge 128K external

Storage
Floppy-Standard 3.5inch Floppy Disk via DMA
Drive Capacity: 360K
2nd Drive Optional
Hard Disk DMA Interface built-in
Data Transfer: 1.33Mbps

Graphics/Video
Bitmapped

Monocrome
640X400
Sync: Seperate 5vdc, 3.3k ohm
Horizontal: 35.7 Khz
Vertical: 71.2 Hz

Color
640X200 X 4 Color
320X200 X 16 Color
Pallette size: 512 Colors
Video: RGB
Sync: 5vdc, 3.3k ohm
Horizontal: 15.75 Khz
Vertical 60 hz

 

User Interface

Keyboard
Standard QWERTY
Seperate Numeric Keypad and cursor cluster

Mouse
2-button control
High precision, non-slip motion-sensor

Sound
3 programmable sound channels
Frequency 30Hz to 125 Khz
Dynamic envelope shaping
Audio out 1.0v peak to peak 10K ohm

Input/Output

Printer
Industry Standard Parallel
23 pin D-type connector

Modem
RS-232-C Standard (DTE)
50-19,200 Baud
25 Pin D-type connector

MIDI (Musical Instrument Digital Interface)
2 Ports: MIDI IN, MIDI OUT/THROUGH
31.25K baud
Optically isolated receiver
5 pin din connectors

Operating System
TOS with GEM Environment
Hierarchical filing with sub-directories and path names
User interface via GEM with self-explanitory command functions
Icons, Multi-Windowing
Drop-down menus
GEM virtual device interface