Hot answers tagged

50

Video game hardware, whether for home consoles or arcade machines, is designed pretty much from scratch. Hardware designers have pretty much free rein on choosing what CPU to use, basing their choice on factors like cost and ease of programming. The Intel 8086, quite frankly, was a poorly designed processor and was never well regarded. While you could ...


49

There are only seven fruit in Pac-man. The way the game calculates the number of fruit to draw is as follows: LD A,(#4E13): Load the level number (at memory address 0x4E13) into A. INC A: Increment A. CP #08: Is A < 8? JP NC,#2C2E: If not, jump to large-number fruit handling code. LD DE,#3B08: Load the address of the cherry into DE. Start the fruit-...


39

This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side. A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times ...


37

The way I understand it, ROMs are like virtual games, Not really. ROMs are a piece of hardware storing a bit image. Like a disk, a tape or a punch card. It holds an image of the game's software. and emulators are like virtual game consoles, or handhelds. Basically yes. What I don't understand is how there are ROMs for arcade games, which don't have ...


35

To understand what was going on with licensed and unlicensed ports of popular arcade games in the 1980s, you have to understand two critical factors. The video gaming culture of the time, and the preeminence of coin-op arcade games. The role of trademarks and legal trademark protections, which was the more crucial law pertaining to arcade game ports at the ...


35

CRTs don't have pixels, they don't work that way. Also, arcade monitors expose all the picture controls at the back so it is possible to adjust them quite extensively. Operators would have made sure that the picture was the right shape and in focus near the edges. Since the controls are all analogue and no-one bothered to measure the display geometry the ...


34

The reason for this glitch is rather obscure; it's not surprising that the developers didn't catch it. It all starts with the tunnels on the sides of the screen. These tunnels allow Ms. Pac-man and the ghosts to move from one side of the screen to the other. But, somewhere in development, somebody decided that the ghosts were moving too quickly through them. ...


32

Ken's answer is close but not quite right. On the real arcade hardware the signal sent to the CRT monitor is read directly from RAM as the electron beam scans over the screen. That means that whatever is shown on screen is whatever is in RAM at the moment the beam passes that area. The game's CPU takes a few frames to draw the entire play area (the girders, ...


28

Dig Dug stores the positions of objects in tables in memory. There are two tables for this: an enemy table containing the positions of up to four Pookas and four Fygars, and a rock table containing the positions of up to six rocks. There is also a table containing tunnel data, but this is stored in a different way. The game divides the playable area into ...


22

Space Invaders uses a simple display format where bytes are read from memory in order via an address counter, and shifted out via a shift register. Timing is controlled by discrete hardware. The video hardware has priority over the CPU. When it needs to read a byte it asserts the 8080's READY signal, giving it exclusive access to the memory bus. This can be ...


21

The other answers already covered a lot, but there is something else that is important but which hasn't already been addressed in detail: Despite appearances to the contrary, arcade machines are quite frequently not built with unique hardware. For example, the hardware originally designed for Galaga was used for several additional games, including well ...


18

The 6502 accesses the Atari Math Box, via a pre-defined memory map and address decoder,[1§I] as a memory-mapped I/O device.[1§IV] The top four bits of the External Address Bus are sent to the address decoder to determine whether to activate the high-score module, the POKEY module or the Math Box for a given operation.[1§IV] The bottom five bits of the ...


14

Did arcade monitors have same pixel aspect ratio as TV sets? Short answer: No, not necessarily. Long Answer: To start with, 'Title Safe Area' is an idea to define the parts of one transmission to be displayed even if any of the many receivers is maladjusted. It's nothing inherent to the TV signal or its definition, it's a safeguard against less than ...


12

Midway's port of Western Gun, known as Gun Fight in the West is the first arcade game that used a microprocessor (the same Intel 8080 used with Space Invaders). The original Western Gun release in Japan used Taito's Transistor-Transistor Logic chip (possibly one in the 7400 chipset family, as used on many of Taito's boards). Dave Nutting made the decision to ...


12

The POKEY module has a random number generator, six scan lines, eight potentiometer ports, three timers, a serial port and four audio channels.[2#1] Hardware The POKEY chip (C012294 (original), C012294-02 (dual-core) and C012294-04 (quad-core))[1§2] have 40 lines. These are: Pin 1: Vss: Ground[1§3] at 0V. Pins 2 - 6: D3, D4, D5, D6, D7: Data Bus I/O.[1§3] ...


11

The biographical evidence for both Jobs and Wozniak indicates that Wozniak's version of Breakout (which is NOT the version Atari would release publicly) was likely developed in the first half of 1974. From the biography of Steve Jobs, we know that in early 1974 Jobs was working at Atari, having been hired in 1973 at the age of 18. We also know that he left ...


11

Quite simple, Nintendo of America was incorporated in 1982 in Redmond (!). Nintendo of America acted from there on as sole copyright holder for all sales within the US. Before that US sales where in the name of the Nintendo (Japan). But copyrights are still today a national issue, where foreign companies may have a hard time to get their rights acknowledged....


11

The three CPUs were designated as follows: CPU 1 - Main game logic and control of the other two CPU 2 - Graphics and enemy movement CPU 3 - Sound The three CPUs communicate via shared RAM. CPU 2 and 3 perform start-up checks (such as a ROM checksum) and then go into infinite loops, with all activity happening inside interrupts triggered by CPU 1. CPU 2 is ...


10

For posterity, here is the solution that allows you to convert the video output of an Atari Centipede arcade game to VGA output. Aquire the GBS-8200 You need to add an additional wire to the video wiring loom for composite sync. This composite sync signal is already generated on the Atari centipede motherboard and is brought to the video connector, but ...


10

Galaga has specialized graphics hardware that draws 64 individual sprites, so to update a screen full of objects you only need to update 256 bytes at the most. The star field is generated completely in hardware with a LFSR (linear feedback shift register), and there is a 8x8 tile map to draw the score and any other text. I'd guess the Galaga CPUs are ...


10

Yes they existed, and they were produced by Sega, with the interactive movie Time Traveler being the most common though Holosseum, an upgrade kit for Time Traveler, is probably the fighting game you are thinking of. It wasn't a real hologram, obviously, but just a 2d image projected via a concave dome-shaped mirror to give the appearance of floating in ...


10

This is rather generic answer. As you point that Space Invaders uses 8080 CPU, it is known that 8080 accesses memory at the rate of 1 access per 3 clock cycles (max.). Other two cycles are freely available for the video system to fetch the required data. For this kind of access to work reliably, DRAM chips must be able to operate at CPU clock speed (i.e. ...


9

A ROM, short for Read-Only Memory, is computer chip with bits stored in it. Unlike RAM chips, the bits are persistent (remain when the power is turned off) and (usually) require a special programming process to change them. An arcade machine of 80s or 90s vintage is just a computer (often a custom-built, somewhat special-purpose computer) which reads the ...


9

I feel like you're remembering the Apple At Play disk that came with the Apple //c. It had Lemonade Stand, Quick Quiz, and Space Quarks (more of a Galaxian clone than Space Invaders, but I didn't know Galaxian when I was young, so I compared it to Space Invaders, too). On Windows 10, I use AppleWin, which is really a //e emulator, but it has all the ...


9

Konix Multisystem: 6 MHz 8086 (1989). Sure, it was cancelled just before release, but it got amazing press (I remember Jeff Minter raving about it at Earls Court) and some of it lived on as the (68k based) Atari Jaguar.


8

I don't remember any embedded games, but I would highly recommend Virtual II (http://www.virtualii.com/) for Apple II emulation. Its free if used in a limited fashion, otherwise you need to buy a license, but it does just about everything you could possibly think of. As far as a short-cut for access to the 'source code', the only thing I can think of is ...


8

I personally have repaired many of these board sets of both vendors. I own a midway space invaders and a few TAITO Space invaders board sets. The differences arise through the licensing agreement. TAITO owns the rights to Space Invaders and then MIDWAY purchased the licensing for North America. The licensing (Along with much much more) said that Midway had ...


8

The original 8086 was quickly overshadowed by the Z80, which was somewhat compatible but easier to work with as it required less support hardware. Also many arcade developers preferred the 6502 and derivatives, and then later the 68000 which was easier to work with on both the hardware and software fronts. Another issue was that the development machines ...


7

The GBS8220 seems to be the standard way to use modern VGA monitors on old arcade machines. Do you know for sure if your Centipede machine outputs CGA/EGA (digital RGBI), or is it 15 kHz VGA (analog RGBHV)? Here is a list of flat panel monitors that support 15 kHz analog RGBHV signals. But they often come with caveats, such as you have to fiddle to get the ...


7

Asteroids is an example of an arcade cabinet that didn’t even use raster graphics, but vector graphics. Battlezone and Lunar Lander were others. They used similar technology to the Tektronix 4000-series terminals of the ’70s, or the IBM 2250: A cathode ray fired into the back of a glass screen coated with phosphors, like in an old-fashioned black-and-...


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