View Full Version : neogeo dev wiki

02-06-2011, 03:22 PM
A message of my friend furtek:

"Hi guys (and girls, if there are any),
Just to let you know that I recently started a wiki devoted to every technical aspects of the NeoGeo systems on wikia:

Edit new adresse

I'm aware that the site already has its own wiki, but it doesn't seem much oriented towards electronics and programming.

Anyone who wants to share his coding tips, snippets, homebrew games/utilites, or knowledge about the hardware is very welcome. I won't act as a mod or generic know-it-all guy as I'm able to accept being wrong about a statement, and know my limits.
Any edits I'd make on contributions would be formatting and categorizing."

Xian Xi
02-06-2011, 07:35 PM
Nice but would be cool if he explained what each chip did. If he doesn't know then he needs to make a list of what needs clarification.

02-06-2011, 09:25 PM
It's a nice initiative especially for repairs. I might get an account and post a few things later. There's a few things out of place with the chips (LSPC<->VRAM, NEO-Bx<->pal RAM etc.), see schematics (http://www.neo-geo.com/forums/showpost.php?p=2893922&postcount=25) that were posted some time ago.

A nice resource of how the hardware functions / what to look for when things mess up would be very helpful.

02-06-2011, 11:25 PM
I have some pinouts on my repair logs site for some of the NEO chipset chips that I and others have reverse engineered.

Feel free to pull content from my repair logs as long as I'm given credit (and the others that submitted chipset info get their credit too)...


02-07-2011, 12:27 AM
I think before it can be taken very seriously you need to switch to MediaWiki and get hosting without soooo many ads, it's really annoying to navigate right now. Also I don't see a way to get English editing instructions apart from using a translator so that's frustrating when it seems all articles are written in English but only hosted on French Wikia.

02-07-2011, 02:29 AM
the wiki beging

you have more information in his page (in french)

02-07-2011, 03:11 AM
I'm sorry for not realizing that Wikia displayed so much ads when browsing the pages without being registered. Everything was transfered to wikki.com: no ads, default look and everything is in English. Here's the new URL:


Thanks for the permission Channelmaniac, I'll get some diagrams done from your pinouts.
Thank you smkdan also for the link to the schematic (that was quite a shock, not a 100 mega one, but still... didn't know that existed). Do you know if anyone started redrawing it with clearer names, or can I start getting to that also ?
What format would you recommend for collaborative editing ?

I've been following a couple of threads over here for some time and I'm very impressed by what you guys are able to do. It'd be great to have some NG/arcade hardware geeks to talk to in France.

Neo Geo MVS
02-07-2011, 10:44 PM
I saw you erased his original website link could you give it to me since I want to put a link on my website for him.

02-08-2011, 01:38 AM
I would like to contribute with more info on the neo-buf chip found on the mvs 1b, but before I have to clarify the info.
I found this schematics on a chinese page. They were talking about making a substitute for that chip, with two ls245. Here's the google-translated text:

SNK NEO-BUF on the deck small square pieces (48P), is actually two 74LS245 internal integration
When it is partially damaged, you can use an external method of adding 74LS245 repair (see photo BUF principle)
1: SNK-NEO-BUF-= Double 74LS245 IC
2: The part in red is a 245, the blue part is another 245
3: E = equivalent to 245-19P enable signal pin,
DR = the same direction with the 245-1P signal pin,
4: In some places BUF-20P and 44P (E) are shared, 21P and 45P (DR) is shared,
In some places it is separate.

Repair Example:
Block the bad one ninety-seven DIP switch in the test table view to "1" state of the.

44P / E - then -> 245-19P enable signal
45P/DR-- access -> 245 - 1P direction signal
46P/A0-- access -> 245-2P (original pin jumped off the circuit board)
245-18P-Access -> BUF-40P/B0; (original pin jumped off the circuit board) is OK.

Two ninety-seven Block GA1-BUF the 46P damage, resulting in no connection with.
44P/E---> 245-19P enable signal
45P/DR---> 245 - 1P direction signal
46P/A0---> 245-18P (original pin jumped off the circuit board)
245-2P-> BUF-40P/B0; (original pin jumped off the circuit board) is OK.

3 of 95 seat repair BUF connected with action and GA11 BUF used the same logic.

As can be seen from the previous two cases:
Since 245 - 1P direction signal (provided by the BUF-45P/DR) different
So BUF-46/A0 and BUF-40/B0 connection with the 245 is just reversed.
In other words, to understand what the practical significance of 1P direction signal.

Practice in the actual repair of the GA11-BUF 95 and 97 of the GA1-BUF in the repair,
Can correspond directly connected, even the 245 are saved! Because here the signal is unidirectional. (See BUF wiring repair photos)

And here the pictures:

Hope it helps, but it would be great if someone make a clearer scheme of how to substitute that chip with two 245... I don't understand that translated thing.

I'm too exhausted at 3.00am but tried to make an attemp: could someone tell me if this is correct?

02-08-2011, 05:45 AM
Do you know if anyone started redrawing it with clearer names, or can I start getting to that also ?

I heard some talk of vectorizing it but I don't think anyone started with it. Those image scans are all we have right now.

Also the current wiki is 100x better than the old, starting to add a few things now

02-08-2011, 10:39 PM
could someone tell me if this is correct?

It's correct as long as they traced the pinout correctly.

02-10-2011, 09:42 PM
It's correct as long as they traced the pinout correctly.

I hope it will help someone else.
I'll try it in the next weeks and will post results here.

02-11-2011, 07:37 AM
At least the enable and direction pins look correct to me, tried them on a desoldered chip. Didn't test all the bits though, but their locations is coherent with a schematic traced from the joypad board of a NGCD.

Something different: I've been trying to get CDDA tracks working, but with no luck for now. The BIOS call which gets D0 as a command/track argument works on emulators since most of them patch the bios to trap the corresponding bios call, but not on the real console.
I noticed that the BIOS saved a computed address starting at $E00000 according to the "CDDA flag" right after the NEO-GEO string in the 68k binaries. That address is then used by the said BIOS call to read two bytes at (address) and (address+2) after asking $E00000~$EFFFFF to be mapped to the Z80 address space.

Is that the "ask the Z80 which track to play" code ?

02-11-2011, 11:44 PM
At least the enable and direction pins look correct to me, tried them on a desoldered chip. Didn't test all the bits though, but their locations is coherent with a schematic traced from the joypad board of a NGCD.

Thanks!! What I don't understand is that line (in that schematic with chinese letters) that joins B0 and B7...

About your Z80 & track question, I remember there's a neogeo programming guide somewhere else that can help you a lot.

02-12-2011, 12:47 AM
The Neo Geo CD FAQ (http://www.egameaddiction.com/neogeocd/reviews/faq/neogeocdfaq.html) is a brilliant source of information.

1.6. Why are games like Metal Slug 3 or King of Fighters 2000 not available
for NGCD?

These two games are very big (688/708 MBits, respectively), so in order to
put them on CD it would have been necessary to heavily cut them down which
would have ruined the game completely.
708 / 8 = 88.5MB :lol:

02-12-2011, 02:18 AM

Kof 2000 was annonced by SNK for the NeoGeo CD, so it's not true than it's a Memory problem, Kof 98 have 683 Mo so it could be on CD.... But Aruze stop just the developpement when he buy the society

For Metal Slug 3 it's an other problem, NeoGeo CD sould charge on his memory the game, so 56 Mb and just 32 for the graphique it's clearly limiting. In fact the game could operate but only if you cut the level with loading