Bally Astrocade
Encyclopedia
The Astrocade is an early video game console
and simple computer system designed by a team at Midway
, the videogame division of Bally. It was marketed only for a limited time before Bally decided to exit the market. The rights were later picked up by a third-party company, who re-released it and sold it until around 1983. The Astrocade is particularly notable for its very powerful graphics capabilities, and for the difficulty in accessing those capabilities.
). In 1979 Bally grew less interested in the arcade market and decided to sell off their Consumer Products Division, including development and production of the game console.
At about the same time a 3rd party group had been unsuccessfully attempting to bring their own console design to market as the Astrovision. A corporate buyer from Montgomery Ward
who was in charge of the Bally system put the two groups in contact, and a deal was eventually arranged. In 1981 they re-released the unit with the BASIC cartridge included for free, this time known as the Bally Computer System, and then changed the name again in 1982 to Astrocade. It sold under this name until the video game crash of 1983
, and then disappeared around 1985.
Midway had long been planning to release an expansion system for the unit, known as the ZGRASS-100. The system was being developed by a group of computer artists at the University of Illinois at Chicago
known as the 'Circle Graphics Habitat'
, along with programmers at Nutting. Midway felt that such a system, in an external box, would make the Astrocade more interesting to the market. However it was still not ready for release when Bally sold off the division. A small handful may have been produced as the ZGRASS-32 after the machine was re-released by Astrovision.
The system, combined into a single box, would eventually be released as the Datamax UV-1
. Aimed at the home computer market while being designed, the machine was now re-targeted as a system for outputting high-quality graphics to video tape. These were offered for sale some time between 1980 and 1982, but it is unknown how many were built.
to design a video display chip that could be used in all of their videogame systems, from standup arcade game
s, to a home computer
system. The system Nutting delivered remains perhaps the most powerful graphics system of the 8-bit generation, and was used in most of Midway's classic arcade games of the era, including Gorf
and Wizard of Wor
.
The basic systems were powered by a Zilog Z80
driving the display chip with a RAM buffer in between the two. The display chip had two modes, a low-resolution mode at 160 × 102, and a high-resolution mode at 320 × 204, both with 2-bits per pixel for four colors. This sort of color/resolution was normally beyond the capabilities of RAM of the era, which could not read out the data fast enough to keep up with the TV display. The chip used a clever trick to work around this problem, technically "holding the RAS high", allowing them to read one "line" at a time at very high speed into a buffer inside the display chip. The line could then be read out to the screen at a more leisurely rate, while also interfering less with the CPU, which was also trying to use the same memory.
Sadly, on the Astrocade the pins needed to use this "trick" were not connected. Thus the Astrocade system was left with just the lower resolution 160 × 102 mode. In this mode the system used up 160 × 102 × 2bits = 4080 bytes of memory to hold the screen. Since the machine had only 4k of RAM, this left very little room left over for the program's use, which was used for things like holding the score, or game options. The rest of the program would have to be placed in ROM.
The Astrocade used color register
s, or color indirection as it was often referred to then, so the four colors could be picked from a palette of 256 colors. Color animation was possible by changing the values of the registers, and using a horizontal blank interrupt
you could change them from line to line. An additional set of four color registers could be "swapped in" at any point along the line, allowing you to create two "halves" of the screen, split vertically. Originally intended to allow you to easily create a "score area" on the side of the screen, clever programmers used this feature to emulate 8 color modes.
Unlike the VCS, the Astrocade did not include hardware sprite
support. It did, however, include a blitter
-like system and software to drive it. Memory above 0x4000 was dedicated to the display, and memory below that to the ROM. If a program wrote to the ROM space (normally impossible, it's "read only" after all) the video chip would take the data, apply a function to it, and then copy the result into the corresponding location in the RAM. Which function to use was stored in a register in the display chip, and included common instructions like XOR and bit-shift. This allowed the Astrocade to support any number of "sprites" independent of hardware, with the downside that it was up to the software to re-draw them when they moved.
The Astrocade was one of the early cartridge-based systems, using cartridges known as Videocades that were designed to be as close in size and shape as possible to a cassette tape. The unit also included two games built into the ROM, Gunfight and Checkmate, along with the simple but useful Calculator and a "doodle" program called Scribbling.
The Astrocade featured a relatively complex input device incorporating several types of control mechanisms: the controller was shaped as a pistol-style grip with trigger switch on the front; a small 4-switch/8-way joystick
was placed on top of the grip, and the shaft of the joystick connected to a potentiometer
, meaning that the stick could be rotated to double as a paddle controller. By most reports the controllers were excellent, but had the downside of breaking frequently.
On the front of the unit was a 24-key "hex-pad" keyboard used for selecting games and options. Most cartridges included two games, and when they were inserted the machine would reset and display a menu starting with the programs on the cartridge and then listing the four built-in programs. On the back were a number of ports, including connectors for power, the controllers, and an expansion port. One oddity was that the top rear of the unit was empty, and could be opened to store up to 15 cartridges. The system's ability to be upgraded from a Videogame console to Personal computer
along with its library of nearly 30 games in 1982 are some reasons that made it more versatile than its main competitors, and was listed by Jeff Rovin as one of the seven major video game suppliers.
BASIC programs were stored in the video RAM by interleaving every bit
of the program along with the display itself; BASIC used all the even-numbered bits, and the display got the odd-numbered bits. The interpreter would read out two bytes, drop all the odd-numbered bits, and assemble the results into a single byte
of code. This was rendered invisible by setting two of the colors to be the same as the other two, such that colors
BASIC was programmed, laboriously, through this keyboard by assigning each of the keys a single command, number and several alpha characters. These were selected through a set of 4 colored shift keys. This way you simply typed "WORD"(gold) shift then the "+" key and got
), 32k of RAM, and a new 32k ROM containing the GRASS programming language
(sometimes referred to as GRAFIX on this machine). The unit also added I/O ports for a cassette and floppy disk
, allowing it to be used with CP/M
.
Video game console
A video game console is an interactive entertainment computer or customized computer system that produces a video display signal which can be used with a display device to display a video game...
and simple computer system designed by a team at Midway
Midway Games
Midway Games, Inc. is an American company that was formerly a major video game publisher. Following a bankruptcy filing in 2009, it is no longer active and is in the process of liquidating all of its assets. Midway's titles included Mortal Kombat, Ms.Pac-Man, Spy Hunter, Tron, Rampage, the...
, the videogame division of Bally. It was marketed only for a limited time before Bally decided to exit the market. The rights were later picked up by a third-party company, who re-released it and sold it until around 1983. The Astrocade is particularly notable for its very powerful graphics capabilities, and for the difficulty in accessing those capabilities.
History
Originally referred to as the Bally Home Library Computer, it was released in 1977 but available only through mail order. Delays in the production meant none of the units actually shipped until 1978, and by this time the machine had been renamed the Bally Professional Arcade. In this form it sold mostly at computer stores and had little retail exposure (unlike the Atari VCSAtari 2600
The Atari 2600 is a video game console released in October 1977 by Atari, Inc. It is credited with popularizing the use of microprocessor-based hardware and cartridges containing game code, instead of having non-microprocessor dedicated hardware with all games built in...
). In 1979 Bally grew less interested in the arcade market and decided to sell off their Consumer Products Division, including development and production of the game console.
At about the same time a 3rd party group had been unsuccessfully attempting to bring their own console design to market as the Astrovision. A corporate buyer from Montgomery Ward
Montgomery Ward
Montgomery Ward is an online retailer that carries the same name as the former American department store chain, founded as the world's #1 mail order business in 1872 by Aaron Montgomery Ward, and which went out of business in 2001...
who was in charge of the Bally system put the two groups in contact, and a deal was eventually arranged. In 1981 they re-released the unit with the BASIC cartridge included for free, this time known as the Bally Computer System, and then changed the name again in 1982 to Astrocade. It sold under this name until the video game crash of 1983
Video game crash of 1983
The North American video game crash was a serious event that brought an abrupt end to what is considered the second generation of console video gaming in North America. Beginning in 1983, the crash almost destroyed the then-fledgling industry and led to the bankruptcy of several companies producing...
, and then disappeared around 1985.
Midway had long been planning to release an expansion system for the unit, known as the ZGRASS-100. The system was being developed by a group of computer artists at the University of Illinois at Chicago
University of Illinois at Chicago
The University of Illinois at Chicago, or UIC, is a state-funded public research university located in Chicago, Illinois, United States. Its campus is in the Near West Side community area, near the Chicago Loop...
known as the 'Circle Graphics Habitat'
Electronic Visualization Laboratory
The Electronic Visualization Laboratory is a cross-disciplinary research lab at the University of Illinois at Chicago. It brings together faculty and students from the Art and Computer Science departments of UIC...
, along with programmers at Nutting. Midway felt that such a system, in an external box, would make the Astrocade more interesting to the market. However it was still not ready for release when Bally sold off the division. A small handful may have been produced as the ZGRASS-32 after the machine was re-released by Astrovision.
The system, combined into a single box, would eventually be released as the Datamax UV-1
Datamax UV-1
The Datamax UV-1 was a pioneering computer designed by a group of computer graphics artists working at the University of Illinois at Chicago, known as the Circle Graphics Habitat...
. Aimed at the home computer market while being designed, the machine was now re-targeted as a system for outputting high-quality graphics to video tape. These were offered for sale some time between 1980 and 1982, but it is unknown how many were built.
Description
In the late 1970s Midway contracted Dave Nutting AssociatesDave Nutting Associates
David Judd Nutting is a graduate of the Pratt Institute with a degree in industrial design. After leaving the Army Corps of Engineers, he joined the design firm of Brooks Stevens Associates. During his time there he was involved in a wide variety of projects, working on everything from Evinrude...
to design a video display chip that could be used in all of their videogame systems, from standup arcade game
Arcade game
An arcade game is a coin-operated entertainment machine, usually installed in public businesses such as restaurants, bars, and amusement arcades. Most arcade games are video games, pinball machines, electro-mechanical games, redemption games, and merchandisers...
s, to a home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
system. The system Nutting delivered remains perhaps the most powerful graphics system of the 8-bit generation, and was used in most of Midway's classic arcade games of the era, including Gorf
Gorf
Gorf is an arcade game released in 1981 by Midway Mfg., whose name was advertised as an acronym for "Galactic Orbiting Robot Force". It is a multiple-mission fixed shooter with five distinct modes of play, essentially making it five games in one...
and Wizard of Wor
Wizard Of Wor
Wizard of Wor is an arcade game from 1981 , developed by Midway. Other systems it was ported to include the Atari 800, Commodore 64, the Atari 2600, Atari 5200 and the Bally Astrocade as "The Incredible Wizard". The title of the game is often misspelled as "Wizard of War"...
.
The basic systems were powered by a Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
driving the display chip with a RAM buffer in between the two. The display chip had two modes, a low-resolution mode at 160 × 102, and a high-resolution mode at 320 × 204, both with 2-bits per pixel for four colors. This sort of color/resolution was normally beyond the capabilities of RAM of the era, which could not read out the data fast enough to keep up with the TV display. The chip used a clever trick to work around this problem, technically "holding the RAS high", allowing them to read one "line" at a time at very high speed into a buffer inside the display chip. The line could then be read out to the screen at a more leisurely rate, while also interfering less with the CPU, which was also trying to use the same memory.
Sadly, on the Astrocade the pins needed to use this "trick" were not connected. Thus the Astrocade system was left with just the lower resolution 160 × 102 mode. In this mode the system used up 160 × 102 × 2bits = 4080 bytes of memory to hold the screen. Since the machine had only 4k of RAM, this left very little room left over for the program's use, which was used for things like holding the score, or game options. The rest of the program would have to be placed in ROM.
The Astrocade used color register
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
s, or color indirection as it was often referred to then, so the four colors could be picked from a palette of 256 colors. Color animation was possible by changing the values of the registers, and using a horizontal blank interrupt
Horizontal blank interrupt
A horizontal blank interrupt is a programming technique used in some systems, notably video games and consoles, to allow program code to be run in the periods when the display hardware is turned off, waiting for the TV to complete its horizontal blank, which takes about 10 μS.The technique was only...
you could change them from line to line. An additional set of four color registers could be "swapped in" at any point along the line, allowing you to create two "halves" of the screen, split vertically. Originally intended to allow you to easily create a "score area" on the side of the screen, clever programmers used this feature to emulate 8 color modes.
Unlike the VCS, the Astrocade did not include hardware sprite
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
support. It did, however, include a blitter
Blitter
In a computer system, a blitter is a circuit, sometimes as a coprocessor or a logic block on a microprocessor, that is dedicated to the rapid movement and modification of data within that computer's memory...
-like system and software to drive it. Memory above 0x4000 was dedicated to the display, and memory below that to the ROM. If a program wrote to the ROM space (normally impossible, it's "read only" after all) the video chip would take the data, apply a function to it, and then copy the result into the corresponding location in the RAM. Which function to use was stored in a register in the display chip, and included common instructions like XOR and bit-shift. This allowed the Astrocade to support any number of "sprites" independent of hardware, with the downside that it was up to the software to re-draw them when they moved.
The Astrocade was one of the early cartridge-based systems, using cartridges known as Videocades that were designed to be as close in size and shape as possible to a cassette tape. The unit also included two games built into the ROM, Gunfight and Checkmate, along with the simple but useful Calculator and a "doodle" program called Scribbling.
The Astrocade featured a relatively complex input device incorporating several types of control mechanisms: the controller was shaped as a pistol-style grip with trigger switch on the front; a small 4-switch/8-way joystick
Joystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...
was placed on top of the grip, and the shaft of the joystick connected to a potentiometer
Potentiometer
A potentiometer , informally, a pot, is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider. If only two terminals are used , it acts as a variable resistor or rheostat. Potentiometers are commonly used to control electrical devices such as volume controls on...
, meaning that the stick could be rotated to double as a paddle controller. By most reports the controllers were excellent, but had the downside of breaking frequently.
On the front of the unit was a 24-key "hex-pad" keyboard used for selecting games and options. Most cartridges included two games, and when they were inserted the machine would reset and display a menu starting with the programs on the cartridge and then listing the four built-in programs. On the back were a number of ports, including connectors for power, the controllers, and an expansion port. One oddity was that the top rear of the unit was empty, and could be opened to store up to 15 cartridges. The system's ability to be upgraded from a Videogame console to Personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
along with its library of nearly 30 games in 1982 are some reasons that made it more versatile than its main competitors, and was listed by Jeff Rovin as one of the seven major video game suppliers.
BASIC
The Astrocade also included a BASIC programming language cartridge, based on Lee Chen Wang's Palo Alto Tiny BASIC. Supporting BASIC on the system was very difficult, because the display alone used up almost all the available RAM. The solution to this problem was very complex, yet very clever.BASIC programs were stored in the video RAM by interleaving every bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
of the program along with the display itself; BASIC used all the even-numbered bits, and the display got the odd-numbered bits. The interpreter would read out two bytes, drop all the odd-numbered bits, and assemble the results into a single byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
of code. This was rendered invisible by setting two of the colors to be the same as the other two, such that colors
01 and 11 would be the same (white), so the presence, or lack, of a bit for BASIC had no effect on the screen. Additional memory was scavenged by using fewer lines vertically, only 88 instead of the full 102. The end result of all this was to manage to squeeze out 1760 bytes of RAM for BASIC programs. The downside was that most of the graphics system's power was unavailable.BASIC was programmed, laboriously, through this keyboard by assigning each of the keys a single command, number and several alpha characters. These were selected through a set of 4 colored shift keys. This way you simply typed "WORD"(gold) shift then the "+" key and got
GOTO.ZGRASS
The ZGRASS unit sat under the Astrocade and turned it into a "real" computer, including a full keyboard, a math co-processor (FPUFloating point unit
A floating-point unit is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root...
), 32k of RAM, and a new 32k ROM containing the GRASS programming language
GRASS programming language
GRASS was a programming language created to script 2D vector graphics animations. GRASS was similar to BASIC in syntax, but added numerous instructions for specifying 2D object animation, including scaling, translation, rotation and color changes over time...
(sometimes referred to as GRAFIX on this machine). The unit also added I/O ports for a cassette and floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
, allowing it to be used with CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
.
Circuit Board and Cartridges
- CPU: Z80, 1.789 MHz
- RAM: 4k (up to 64k with external modules in the expansion port)
- ROM: 8k
- Cart ROM: 8k
- Expansion: 64K total
- Ports: 4 controller, 1 expansion, 1 light pen
- Sound: 3 voices + noise/vibrato effects (played through the TV)
Video
- Resolution: True 160×102 / Basic 160×88 / Expanded RAM 320×204
- Colors: True 8* / Basic 2
- The bitmap structure of the Bally actually only allows for 4 color settings. However, through the use of 2 color palettes and a left/right boundary control byte you could have the left section of screen (this could be the play field) use 1 set of colors while the right side (this could show information such as lives and score) used an entirely different set of colors, thus 8 total colors were possible.
- Graphic type: Bitmap, 2 plane bitpacked
List of games
- 280 Zzzap / Dodgem
- Amazing Maze / Tic Tac Toe
- Artillery Duel
- Astro BattleAstro Battle (arcade game)Astro Battle is a Space Invaders clone arcade game released by Bally in 1977 For the Bally Astrocade arcade system. The aim is to defeat waves of aliens with a laser cannon and earn as many points as possible....
(originally titled Space Invaders) - Bally Pin
- BASICBASICBASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....
(not a game but included for completeness ) - Baseball
- Basketball
- Bingo Math / Speed Math
- Biorhythm
- Blackjack / Poker / Acey-Deucey
- Blast Droids
- Bowling
- Checkers / Backgammon
- Clowns / Brickyard
- Coloring Book
- Conan The Barbarian
- Cosmic Raiders
- Dog Patch
- Drag Race / Desert Fox
- Football
- Galactic Invasion (originally titled Galaxian)
- GalaxianGalaxianis an arcade game developed by Namco in 1979. It was published by Namco in Japan and was imported to North America by Midway in 1980. A fixed shooter-style game in which the player controls a spaceship at the bottom of the screen and shoots enemies descending in various directions, it was designed...
- Grand Prix / Demolition Derby
- Gunfight
- ICBM Attack
- Letter Match / Spell 'N Score / Crosswords
- Machine Language Manager (not a game but included for completeness )
- Mazeman
- Median
- Missile Attack
- Ms. CandyMan
- Muncher
- Music Maker
- Panzer Attack / Red Baron
- Pirates Chase
- Sea Devil
- Seawolf / Missile
- Soccer
- Solar Conqueror
- Space Fortress
- Space InvadersSpace Invadersis an arcade video game designed by Tomohiro Nishikado, and released in 1978. It was originally manufactured and sold by Taito in Japan, and was later licensed for production in the United States by the Midway division of Bally. Space Invaders is one of the earliest shooting games and the aim is to...
- Star Battle
- The Incredible Wizard
- Tornado Baseball / Tennis / Hockey / Handball
- Treasure Cove
- War