# Arcade games This section covers arcade boards from discrete logic to the PC-based systems. Each page covers one era or one family of boards. Many boards were built for one game or a few games. The MAME driver source for a board lists its chips, its crystals, its clock dividers and its screen timing. It usually gives more detail than any other public source. ## Across all boards - [Practices for arcade work](https://tanepiper.github.io/game-frame/arcade/practices.md): MAME driver source, machine flags, ROM sets and CHD, NVRAM and DIP settings as test inputs, attract mode, input recording, refresh rates and frame drift. - [Encryption and protection](https://tanepiper.github.io/game-frame/arcade/protection.md): suicide batteries, the Sega, Capcom, Konami and SNK ciphers, protection MCUs, Phoenix sets and desuicide work. ## 2D boards - [Discrete logic and the 8080](https://tanepiper.github.io/game-frame/arcade/discrete-and-8080.md): Pong, Breakout and Space Invaders. - [Z80 and 6502 boards](https://tanepiper.github.io/game-frame/arcade/z80-and-6502-era.md): Galaxian, Pac-Man, Galaga, Donkey Kong, Asteroids, Sega System 1, the VS. System and the PlayChoice-10. - [Williams and Midway](https://tanepiper.github.io/game-frame/arcade/williams-and-midway.md): the Williams 6809 boards, the Midway Y, T and W-units, and Midway Zeus. - [Atari coin-op boards](https://tanepiper.github.io/game-frame/arcade/atari-coin-op.md): Atari System 1, System 2, Hard Drivin' and GT. - [Sega 2D boards](https://tanepiper.github.io/game-frame/arcade/sega-2d.md): System 16B, System 18, the X Board and the Y Board. - [Capcom CPS](https://tanepiper.github.io/game-frame/arcade/capcom-cps.md): CPS-1, CPS-2 and CPS-3. - [Neo Geo](https://tanepiper.github.io/game-frame/arcade/neo-geo.md): the MVS and the AES. - [Other 2D makers](https://tanepiper.github.io/game-frame/arcade/other-2d-makers.md): Namco System 1 and 2, Konami, Taito F2 and F3, Irem M72 and M92, Data East, Toaplan and Cave. ## 3D, console-derived and PC boards - [Early 3D boards](https://tanepiper.github.io/game-frame/arcade/early-3d.md): Namco System 21 and 22, Sega Model 1, 2 and 3, Taito JC, Konami GTI Club and Hornet, and Gaelco 3D. - [Console-derived boards](https://tanepiper.github.io/game-frame/arcade/console-derived.md): ZN-1 and ZN-2, Namco System 11 and 12, ST-V, NAOMI, Atomiswave, Triforce, Chihiro, System 246 and the Bemani boards. - [PC-based boards](https://tanepiper.github.io/game-frame/arcade/pc-based.md): the Taito Type X family, Sega Lindbergh, RingEdge to ALLS and Namco ES1 and ES3. ## How arcade work differs from console work A console has one hardware design for every game. An arcade board was often built for one game or for a short run of games. Each board family has its own memory map, clocks and protection. Arcade refresh rates are rarely 60 Hz. They run from about 54.71 Hz on Midway's TMS34010 boards to about 61.5 Hz on Atari's Asteroids. A port must run at the board's own rate to stay in step with a recording of the original. The [practices page](https://tanepiper.github.io/game-frame/arcade/practices.md#refresh-rates-and-frame-drift) has the table. Later boards add three problems. 1. From the 1980s, many boards use battery-backed custom CPUs that decrypt the program. A disassembly of the raw ROM is unreadable until you decrypt it with the CPU's method. 2. From 1988, 3D boards split the game across a main CPU and one or more DSPs. Each DSP runs its own program. Ghidra has no built-in module for most of those DSPs. 3. From 2004, the boards are x86 PCs. The game code is decrypted only on a running machine with its keychip. ## Order of work 1. Read the MAME driver for the board. Note the clocks, the screen totals and the machine flags. 2. Decrypt the program wherever the board has a custom CPU, before any disassembly ([protection](https://tanepiper.github.io/game-frame/arcade/protection.md)). 3. On a 3D board, capture the DSP programs too. They hold part of the game. 4. Record the DIP settings, the BIOS, the region and the NVRAM image with every test case ([practices](https://tanepiper.github.io/game-frame/arcade/practices.md#nvram-and-dip-settings-as-test-inputs)). 5. Check MAME's flags before using it as ground truth. If MAME does not run a game, take ground truth from another emulator or from owned hardware. ## Page layout Each family page opens with one short paragraph and a table that compares its boards. Then it has one section per board. Each board section has the same headings in the same order. 1. **Hardware**: the years, the CPUs and clocks, the sound chips, the screen timing. 2. **Protection**: encryption, protection MCUs and key chips. 3. **Tools**: MAME status, Ghidra and Unicorn support, other emulators. 4. **Projects to learn from**: disassemblies, source releases and re-releases. 5. **For an exact reimplementation**: what to settle before porting. A refresh rate marked "(computed)" is the pixel clock divided by the horizontal and vertical totals in the MAME driver. It comes from MAME's model of the board. It is not a separate measurement. A fact marked "(not confirmed)" has one source and lacks a second. A fact marked "(secondary source)" comes from a forum, a wiki copy or a press report. MAME's flags and entry counts change with each release. Encryption and protection are described factually. The law on working around them differs by country ([Legal](https://tanepiper.github.io/game-frame/legal.md), [the law worldwide](https://tanepiper.github.io/game-frame/preservation/law/index.md)). You decide which route to take. ## Related pages - [CPU families](https://tanepiper.github.io/game-frame/computers/cpu-families.md): byte order, Ghidra and Unicorn support, and arithmetic traps for the Z80, 6502, 6809, 68000, x86, SuperH, MIPS and PowerPC. - [Tools for console work](https://tanepiper.github.io/game-frame/consoles/tools.md) and [matching decompilation](https://tanepiper.github.io/game-frame/consoles/matching-decomp.md). - [Sound](https://tanepiper.github.io/game-frame/hardware/sound.md) and [running the original](https://tanepiper.github.io/game-frame/observe/running-the-original.md). - The skills for each step: [re-inventory](https://tanepiper.github.io/game-frame/skills/re-inventory.md), [re-observe](https://tanepiper.github.io/game-frame/skills/re-observe.md), [re-ghidra](https://tanepiper.github.io/game-frame/skills/re-ghidra.md), [re-emulate](https://tanepiper.github.io/game-frame/skills/re-emulate.md), [re-port](https://tanepiper.github.io/game-frame/skills/re-port.md) and [re-verify](https://tanepiper.github.io/game-frame/skills/re-verify.md).