User:Rom1

The NeoGeo Development Wiki

This wiki is about every technical aspects of the SNK NeoGeo hardware and software (AES, MVS, CD and CDZ).
Our aim is to provide the most detailed, accurate and up to date information for preservation, homebrew development and repairs.

Base system

What's common to every NeoGeo system: main architecture, data formats...

Last edits

BIOS RAM locations	21:25, 11 August 2025
Pinouts	15:34, 23 July 2025
Memory mapped registers	19:21, 10 April 2025

42 pages

Videosystem

How graphics are handled and displayed, from bitplanes and colors to the video output.

Last edits

Slowdown	07:12, 12 September 2025
Fix bankswitching	21:25, 14 May 2025
Sprites	21:18, 14 May 2025

36 pages

Audio system

Everything related to music and sound effects: The Z80 subsystem, synthesized and sampled sound, CDDA playback...

Last edits

NEO-ZMC	15:45, 1 May 2025
ADPCM	15:17, 15 March 2025
CDDA	03:49, 10 February 2025

28 pages

Repairs

Troubleshooting dead or glitchy MVS boards, CD laser assemblies, cartridges...

Last edits

Replacement chip	20:21, 25 January 2026
CD drive	07:36, 1 November 2025
List of ROM chips	00:03, 26 September 2025

45 pages

Cart systems

Particularities of the AES and MVS systems: ROM types, memory cards, cab I/O, data security... Also cartridge boards information.

Last edits

Category:Cartridge boards	13:23, 10 January 2026
Cartridges	18:19, 7 January 2026
PROG board	07:40, 7 January 2026

106 pages

CD systems

NeoGeo CD and CDZ specificities: Differences and limitations, new memory functions, CDDA...

Last edits

CD drive	07:36, 1 November 2025
CDROM-2 board	01:49, 18 August 2025
CD hardware versions	01:44, 18 August 2025

48 pages

Software

Code snippets, register definitions, guides on how to display stuff, use the system ROM, play music and sounds, read user input...

Last edits

Development tools	14:00, 6 October 2025
PLAYER START subroutine	12:00, 6 October 2025
Slowdown	07:12, 12 September 2025

60 pages

Electronics

What makes everything work (or not). Schematics, chip pinouts and functions, troubleshooting hardware issues...

Last edits

Replacement chip	20:21, 25 January 2026
NEO-SMA	15:37, 15 January 2026
NEO-CMC	23:04, 10 January 2026

109 pages

Games

Remarquable games for some of their technical aspects: special effects, unusual hardware use, hidden features...

Last edits

The King of Fighters '99 - Millennium Battle	15:07, 15 January 2026
Garou - Mark of the Wolves	15:06, 15 January 2026
Metal Slug 3	15:05, 15 January 2026

241 pages

Recent changes (minor edits hidden)

List of abbreviations:

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m

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25 January 2026

20:21

Replacement chip‎ diffhist +472‎ Furrtek talk contribs (Updated options, reasoning, done/todo)

About this wiki

• The wiki has 579 pages thanks to our contributors
• Hosting provided by ElBarto
• Don't know where to start ? Try here
• Can't find what you're looking for ? Try our links
• Want to help ? Just register or join us on IRC ! [Freenode #neogeodev]
• How to edit, guidelines, available templates, suggestions: The wiki

Todo

• See wanted pages, old pages, short pages, and Todo/Mysteries.
• Publish asm highlighter for ConTEXT
• Make subcategories, move/merge "BIOS calls"
• More schematics, chip details/pinouts
• Troubleshooting tips
• Make a downloadable offline capture every few months ?