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Bally Professional Arcade/Astrocade
Console Information

The Bally Professional Arcade's beginnings date back
to the late 1970s when Midway Manufacturing (the video game division
on Bally) contracted Dave Nutting Associates to design a video display
chip for use in their arcade and video game systems. Powered by
a Zilog Z80 processor, the system he developed is still considered
one of the most powerful systems in the 8-bit generation and was
used in most of Midway's classic arcade games (such as Gorf).
This same system was used in the Bally Professional
Arcade, although not to the same extent as in the Arcade machines
as the Professional Arcade only allowed for the low-resolution mode
of the system and not the high- and low-resolution modes available
in the Arcade machines. The Bally Professional Arcade itself was
designed by a team at Midway, and originally named the "Bally
Home Library Computer" and only available through mail order
upon its release in 1977. Delays in the production menat that none
of the units were actually shipped until 1978. By this time the
system had been renamed the "Bally Professional Arcade"
and was now available in retail stores (mostly computer stores)
and had little publicity when compared to the Atari
Video Computer System.
Due to such competition, the system was withdrawn
in 1979 and Bally decided to sell off their Consumer Products Division,
including development and production of the console. By this point,
a dedicated user base had grown who saw the system's potential through
the Basic Programming cartridge. A group of them bought the rights
to the system off Bally in 1980 and set up a company called Astrovision.
They re-introduced the system in 1981 as the "Bally Computer
System", which came with a free Basic Programming Cartridge.
In 1982, they changed the system name to "Astrocade" and
continued production until about 1985, when it was discontinued
after the video game crash of previous years.
Due to the bitmap structure of the system, this allows
for 4 colour settings, however, by dividing the screen with a left/right
boundary control byte, 2 sets of colours could be used on the 1
screen.
The system uses custom cassettes for its programs
which were designed similar to audio cassettes (same dimensions).
The system displays a menu showing the system's built-in programs
(2 games, a calculator and a drawing program) as well as the contents
of the inserted cassette. The controllers are pistol-shaped with
a trigger with a knob at the top which acts as a paddle and short-throw
joystick. These controllers are very responsive when compared to
other systems controllers of the time.
There were quite a few games produced for the system,
some which were programmed in Bally/Astro Basic. These Basic games
were found to be a little slow at times, which prompted production
companies to use Machine Language routines from the built-in games
to power their games - a hybrid programming method that produced
good results using the limited amount of space available in the
unit. Other games were entirely written in Machine Language. Hiding
the Machine Language code at the bottom of the screen by reducing
the vertical resolution would allow 4-8 colours to be displayed
on-screen (the same quality as a cartridge game).
Bally Professional Arcade/AstrocadeTechnical Specifications
- CPU: Zilog Z80 Processor running at 1.8MHz (up to 3.579MHz)
- Resolution: True 160 x 102 x 2 (4 colours), Basic 160 x 88 x
1 (2 colours)
- Graphics: Bitmap, 2-plane, bit-packed
- RAM: 4K (up to 64K with external modules in the expansion port)
- ROM: 8K
- Cartridge ROM: 8K
- Colours: 8 x 2
- Colour Palette: 32 Colours, 8 intensities, 256 total
- Expansion: 64K total
- Sound: 3 voice + Noise & Vibrato effects
- Ports: 4 controller ports, 1 expansion port, 1 light pen port
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