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54-521: In the late 1970s, Midway contracted Dave Nutting Associates to design a video display chip that could be used in all of their videogame systems, from standup arcade games , to a home computer system. The system Nutting delivered was used in most of Midway's classic arcade games of the era, including Gorf and Wizard of Wor . The chipset supported what was at that time relatively high resolution of 320×204 in four colours per line , although to access this mode required memory that could be accessed at

108-497: 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 is "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

162-411: 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. 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. The Astrocade featured

216-576: A horizontal blank interrupt they could be changed from line to line. An additional set of four color registers could be "swapped in" at any point along the line, allowing the creation of two screen "halves", split vertically. Originally intended to allow creation of a score area on the side of the screen, programmers also used this feature to emulate 8 color modes. Unlike the VCS, the Astrocade did not include hardware sprite support. It did, however, include

270-499: A horizontal blank interrupt ) is an interrupt signal in a legacy computer system which is used for display timing. It is usually, though not always, generated by a system's graphics chip as the scan lines of a frame are being readied to send to the monitor for display. The most basic implementation of a raster interrupt is the vertical blank interrupt . Such an interrupt provides a mechanism for graphics registers to be changed mid-frame, so they have different values above and below

324-569: A 'vertical interrupt' source to reposition the hardware sprites on the screen. The C64 's and C128 's VIC-II has a flexible raster interrupt system. Raster interrupts and CPU intervention are necessary to reuse sprites on the screen, mix graphics modes, and selectively scroll screen regions. Raster interrupts are also supported by the Plus/4 's and C16 's TED . The Nintendo Entertainment System 's PPU graphics chip does not support true raster interrupts - an interrupt can be set to trigger during

378-724: A department store salesman, David joined the Army Corps of Engineers and intended to follow a career path in engineering. After a year studying at Denison University , Nutting learned about the discipline of industrial design . He switched colleges to the Pratt Institute in their industrial design program, then rejoined the Army Corps of Engineers. Thereafter, he joined prestigious industrial design firm Brook Stevens Associates in Milwaukee, Wisconsin. He worked to design

432-697: A design based on the legacy of the Jeep automobile. His design was subsequently chosen for what was called the Jeep Wagoneer , thereafter inaugurating the category of sport utility vehicles (SUVs). David became involved with the coin-operated games industry after his brother, Bill Nutting, started as an agent for the Knowledge Computer (1963) electro-mechanical quiz game . The device needed redesigning, so David and his friend Harold Montgomery who worked at engineering firm Cutler-Hammer created

486-595: A faster rate than the common 2 MHz dynamic RAM of the era. 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

540-462: A full keyboard, a math co-processor ( FPU ), 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 . Games magazine included Bally Professional Astrocade in their "Top 100 Games of 1981", noting that "Our favorite cartridges are

594-415: A key press, which could be output to TV , meaning that characters could be read in from the keyboard, stored in an array, and then output. The character display was 11 lines of 26 characters across. The resolution for the graphic commands is 88x160, with X ranging from -80 to 79 and Y ranging from -44 to 43. Music could be produced in four ways: The following sample program from the manual demonstrates

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648-468: A microprocessor. Dave Nutting Associates kept close communication with Bally as they continued to work on microprocessor prototypes. After producing a working example of a video game, Bally proposed that Dave Nutting Associates adapt the Taito game Western Gun (1975) to a microprocessor. Dave, working with Fredriksen as hardware designer and University of Milwaukee graduate Tom McHugh as programmer, designed

702-473: A mostly autonomous operation focused around video game development for their subsidiary Midway. They also developed and released the Bally Professional Arcade console, developed by team members at Dave Nutting Associates. David mentored a number of arcade game designers at his company. These included Alan McNeil, creator of Berzerk (1980), and Jamie Fenton , creator of Gorf (1981). Another employee, Bob Ogdon, later took over development of home games for

756-547: A new company in 1971 called Milwaukee Coin Industries Inc. (MCI) with partner David Winter, dedicated to producing electro-mechanical games starting with Red Baron . The company did well in the business of arcade games and recruited engineers from the Milwaukee area to help implement David’s game ideas. In 1972, former Air Force engineer Jeffery Frederiksen began working with MCI as a contractor. Trained in solid-state electronics and computer engineering, Frederiksen

810-468: A new version of the machine. After a falling out between the brothers, David and Harold decided to form their own company, Nutting Industries, in Milwaukee to distribute their device. They launched their machine I.Q. Computer (1967) to the coin-op industry in 1967, competing with Nutting Associates ’ Computer Quiz (1966). David continued to design the games produced by Nutting Industries, initially different styles of quiz games. Nutting Industries opened

864-399: 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 . On the front of the unit

918-567: A single scan line. Modern protected mode operating systems generally do not support raster interrupts as access to hardware interrupts for unprivileged user programs could compromise the system stability. As their most important use case, the multiplexing of hardware sprites, is nowadays no longer relevant there exists no modern successor to raster interrupts. Several popular home computers and video game consoles included graphics chips supporting raster interrupts or had features that could be combined to work like raster interrupts. The following list

972-444: A subsidiary called Modec to expand into the teaching machine market outside of the coin-op industry, which wound up as a financial disappointment. Nutting and Montgomery convened to create a traditional electro-mechanical shooting game called Red Baron (1971), which was the final game released by Nutting Industries. Nutting Industries entered receivership, but David purchased the company’s assets with his personal finances. He formed

1026-511: 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. 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

1080-456: A working unit which ran using a microprocessor, the implementation of which was subsequently patented. Bally representatives were impressed with the demonstration, but did not produce a pinball game based on the technology. Instead, David offered the design to Mirco Games in Arizona, who produced the pinball table The Spirit of ’76 (1975) which was the first commercial pinball table to use

1134-583: Is not exhaustive. The Bally Astrocade supported a horizontal blank interrupt to select the four screen colors from a palette of 256 colors. The Astrocade did not support hardware sprites. The ANTIC chip used by the Atari 8-bit computers includes display list interrupts (DLIs), which are triggered as the display is being drawn. The ANTIC chip itself is considerably powerful and inherently capable of many features which other systems require raster interrupts to duplicate. ANTIC can mix multiple graphics modes on

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1188-516: The Atari VCS ). 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 third-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

1242-549: 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 videotape . These were offered for sale some time between 1980 and 1982 , but it is unknown how many were built. The basic system

1296-444: The microprocessor , but the executive board of MCI was not interested. In 1972, they had opened their Red Baron Amusement Center arcade locations and increasingly wanted to exit game manufacturing. David was removed from the company, though he allowed them use of the building under his lease as they wound down manufacturing. He and Frederiksen jointly established a new research and development company dedicated to coin-op games located in

1350-457: The vertical blank interval, but not at any arbitrary scan line - instead required polling of a "hit flag" that indicated when the first sprite was being drawn. Although early games like Super Mario Bros. , Castlevania , and The Legend of Zelda managed to produce effective split-screen scrolling with this method, it is CPU-intensive. Some later cartridges incorporated MMC circuitry (most prominently Nintendo's MMC3 chip) that kept track of

1404-581: The Bally Professional Arcade with his company Action Graphics with Nutting’s support. David continued to design arcade games including Wizard of Wor (1981) and quiz game Professor Pac-Man (1983). Eventually, Dave Nutting Associates was sidelined in favor of Midway’s internal development. David Nutting worked on several unreleased games, including a proposal for the game that eventually became Tron (1982). With home games being developed by Action Graphics and arcade games handled by

1458-605: 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 , with the name changing 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

1512-499: The Midway team, Bally closed Dave Nutting Associates in 1984. Nutting left the industry and Jeff Frederiksen moved on to work in graphical display technology, which he had worked on as part of his work with the GRASS programming language on the Bally Professional Arcade. In the following years, Nutting moved to Colorado spent time pursuing interests in aviation. He built an experimental helicopter called Tiger Shark. David returned to

1566-517: The PAUSE key would load the next character from memory. An Astro BASIC program that later became commercialized is Artillery Duel . John Perkins wrote the game first and submitted it to The Arcadian fanzine , from which it was adapted for the Astro BASIC manual. Perkins subsequently developed the Astrocade cartridge of the game. Astro BASIC supported the following keywords: A period . at

1620-670: The PPU's address and data lines and generated raster interrupts. The IBM PCjr using the Video Gate Array graphics chip supported a 'vertical retrace interrupt' implemented as IRQ5. Later in 1984, IBM introduced the EGA graphics standard which also supported a vertical retrace interrupt, but implemented as XT IRQ2 and disabled by default. However, not all EGA cards implemented this feature and just very few programs utilizing EGA modes relied on it. Modern GPUs have an IRQ registered on

1674-454: The back of the building, Dave Nutting Associates. Their first contact in the industry was with Bally Mfg, who were interested in the proposed application of the microprocessor to their pinball business. Nutting and Frederiksen acquired a development kit for the Intel 4040 microprocessor and obtained a table of Bally’s Flicker (1974) to experiment with. On September 26, 1974, they demonstrated

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1728-455: The classic Gunfight, Red Baron air war, and Demolition Derby." Danny Goodman of Creative Computing Video & Arcade Games stated in 1983 that Astrocade "has one of the best graphics and sound packages of any home video game". There are 28 officially released video games for the system. Other cartridges Prototypes Unlicensed Homebrew Dave Nutting Associates David Judd Nutting (December 26, 1930 – September 23, 2020)

1782-548: The coin-op industry in 1993, designing a video-based baseball pitching game. He later wrote two books, the quantum mechanics primer Language of Nature: Quantum World Revealed (2005) and the creative motivational book Secrets of a Creative Mind (2012). David married Phyllis Mason on August 8, 1953. They had a daughter named Elizabeth. He died at his home in Green Valley, Arizona, on September 23, 2020. Horizontal blank interrupt A raster interrupt (also called

1836-401: 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. This managed to squeeze out 1760 bytes of RAM for BASIC programs. The downside was that most of the graphics system's power

1890-500: The contents of a custom chip hardware register. This is typically used for modifying display parameters, such as mixing display modes, reusing sprites, or changing color registers, but can also be used to trigger a CPU interrupt. The X68000 , a 16-bit home computer sold in Japan, has a flexible raster interrupt system to multiplex hardware sprites. The Game Boy 's PPU has support for four raster interrupts: it can be set to trigger at

1944-425: The display chip, and included common instructions like XOR and bit-shift . This allowed the Astrocade to support any number of sprite-like objects 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

1998-413: The interrupt point. This allows a single-color object such as the background or the screen border to have multiple horizontal color bands , for example. Or, for a hardware sprite to be repositioned to give the illusion that there are more sprites than a system supports. The limitation is that changes only affect the portion of the display below the interrupt. They don't allow more colors or more sprites on

2052-399: The joystick input and graphics functions. "Try your skill... The first player's knob moves the phaser left or right and the trigger shoots... Player two controls the target while player one shoots." This listing illustrates how keywords, which were tokenized, were always displayed with a following space. The ZGRASS unit sat under the Astrocade and turned it into a "real" computer, including

2106-486: The main processor. Importantly, this is neither a vertical nor a horizontal 'blank interrupt' and it is handled by the device driver for the graphics card. MSX2 computers feature a Yamaha V9938 graphics chip that, like the NES, supports 'vertical blank interrupts' but requires polling for 'horizontal blank interrupts'. It was commonly used to create split screens, mix multiple video modes together on one screen and to increase

2160-525: The number of unique colours on the screen beyond the official spec. Prominent usage examples are the Aleste series and Konami's Space Manbow . The Amiga computers include a custom coprocessor called the Copper which is dedicated to servicing raster interrupts. The Copper runs a program of simple instructions directing it to wait for a specific vertical scan line and horizontal beam position, then update

2214-504: The physical shape of many different items for clients including 3M , Studebaker , cookware for Mirro , tractors for Bolens , and Evinrude Outboard Motors . He also designed one of the first computer-controlled interfaces for milling machines . In 1961, Brooks Stevens Associates received a contract from Willys to design an update on the concept of the station wagon. Though the initial design parameters called for Detroit automotive style exteriors, Nutting worked on his own time to create

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2268-584: The screen, display horizontal and vertical overscan graphics, and fine scroll selected horizontal regions. DLIs on the Atari are typically used to add additional color to the display and reuse Player/Missile graphics elements. The ColecoVision , an 8-bit game console released in 1982, as well as the MSX , a standardized home computer from 1983, utilized the Texas Instruments TMS9918 . It includes

2322-470: The screen. Since the machine had only 4 kiB (4096 bytes) of RAM, this left very little room for program functions such as keeping score and game options. The rest of the program would have to be placed in ROM . The Astrocade used color registers , or color indirection , 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

2376-461: The start of the line was equivalent to REM in other BASIC implementations. Certain commands were handled by the keypad instead of by keywords: the RESET button was equivalent to NEW in other interpreters. The language supported 26 integer variables A to Z , and two pre-defined arrays , @() - which was stored starting after the program, ascending - and *() - which was stored from

2430-470: The top of memory, descending. The language lacked a DIM statement for dimensioning the arrays, the size of which was determined by available memory ( SZ ) not used by the program listing (2 bytes per item). Ports were accessed via the array &() , and memory was accessed via the array %() , rather than using PEEK and POKE . While the language lacked strings, KP would provide the ASCII value of

2484-562: 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

2538-479: The video game Gun Fight (1975) which became a huge hit and the first commercially successful video game using a microprocessor. Dave Nutting subsequently designed Sea Wolf (1976) which was the highest grossing arcade video game of 1976 and 1977. Sequels to Western Gun and Sea Wolf – Boot Hill (1977) and Sea Wolf II (1977), respectively – were also successful. Bally purchased Dave Nutting Associates in 1977, moving it to Illinois and allowing Nutting to run

2592-532: Was a 24-key "hex-pad" keyboard used for selecting games and options as well as operating the calculator. 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 video game 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

2646-594: Was an industrial design engineer who played a role in the early video game industry . He also designed the exterior of the Jeep Wagoneer . David Judd Nutting was born in 1930 to parents Harold Judd Nutting and Margaret P. Peet in River Forest, Illinois. He was the youngest of four brothers, including the second oldest brother William Gilbert "Bill" Nutting. David came to be interested in engineering, disassembling and reassembling household items to understand how they worked. Despite pressure from his father to become

2700-425: Was listed by Jeff Rovin as one of the seven major video game suppliers. The Astrocade also included a BASIC programming language cartridge, written by Jamie Fenton , who expanded Li-Chen Wang 's Palo Alto Tiny BASIC . First published as Bally BASIC in 1978. Developing a BASIC interpreter on the system was difficult, because the display alone used up almost all the available RAM. The solution to this problem

2754-533: Was 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 system used page mode addressing allowing them to read one "line" at

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2808-457: Was recognized by David Nutting for his technical skill. Nutting increasingly wanted to explore the benefits of solid-state electronics and the two of them collaborated on a game called The Safe (1974) which utilized integrated circuits for the game logic. Shortly thereafter, David heard about the potential of the Intel microprocessor. Both he and Frederiksen wanted to pursue creating games using

2862-406: Was to store the BASIC program code in the video RAM. This was accomplished by interleaving every bit of the program along with the display itself; BASIC used all the even-numbered bits, and the display 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

2916-447: Was unavailable. Programs were entered via the calculator keypad, with a plastic overlay displaying letters, symbols, and BASIC keywords. These were selected through a set of 4 colored shift keys. For example; typing "WORD"(gold) shift then the "+" key would result in GOTO . A simple line editor was supported. After typing the line number corresponding to an existing program, each press of

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