Debug for NeoCD

[smkdan]

nothing really interesting has been added.

-it now remembers cheats in your save data
-saves are checksummed to protect against corruption
-I have a working memory card code (in my custom MAME build) that uses a 2MBit card properly. 900+ 256 byte saves are confirmed working so I have plenty of headroom to fit everything I'll need if NTM ends up making a large expansion mod for the system.
-made cheat engine bit more robust. Should feel like softdips:

The last 'cheat' looks dumb compared to the rest but it's one the things I didn't like about NAM. The crosshair moves too slowly so I patched the game to allow fine tuning. Same thing with magician lord patched to let more than 2 shots on screen at a time. Various tweaks will come later on.

SS1/SS2 have terrible load times for what they are and I'm pretty sure I can reduce them a bit if my plan is any good. Other games will follow if the interest remains. Games like turfmasters are already well optimized (I saw it use RAM very effectively to cache what is frequently needed) so I obviously won't bother with those sorts of games unless the speedup is very easy.

 

[NeoTurfMasta]

nothing really interesting has been added.

-it now remembers cheats in your save data
-saves are checksummed to protect against corruption
-I have a working memory card code (in my custom MAME build) that uses a 2MBit card properly. 900+ 256 byte saves are confirmed working so I have plenty of headroom to fit everything I'll need if NTM ends up making a large expansion mod for the system.

Holy shit! That size shouldnt be a problem. The only problem I see is making it compatible with both cart and cd. What I could do is addition to the traditional 2-16k memory card support, I can have a 2Mbit chip on the adapter inside the CD system. The user can then hard switch between the larger internal chip and the NeoSaveMasta's 16k banks. They'd still be able to transfer internal CD saves to the smaller card if they need to (I think).

Great idea on the Nam cross-hair acceleration!

 

[smkdan]

Sounds alright. If money (or battery life?) was not an issue then 8Mbits worth of SRAM would've been nice. Not for save data, but for a cache to use with CD loads. 768KB extra to buffer stuff (even if it's compressed) could cut out loads for stuff that is constantly swapped out/in. Too bad about the prices though.

 

[NeoTurfMasta]

8Mbit may be possible without spending a lot, or loosing batt life. I'll look around and see if I have anything with a 8Mbit chip on it that I can rip off.

Another idea... for cached data. This sounds a bit crazy, but why not have a (or several) roms on there with precahced data? The legality of that may be called into question, but it may actually be possible. Like a multicart for CD

 

[Razoola]

8Mbit may be possible without spending a lot, or loosing batt life. I'll look around and see if I have anything with a 8Mbit chip on it that I can rip off.

Another idea... for cached data. This sounds a bit crazy, but why not have a (or several) roms on there with precahced data? The legality of that may be called into question, but it may actually be possible. Like a multicart for CD

You will be ok providing data is transfered from CD to memory card via the CD system each time the game is loaded first.

I think the only reason those HK bootleggers have not done something like you suggest in the past is the fact that the CD is still needed for music. If it were not for that Im sure they would have come up with a memory card with all CD games on long ago for ultra fast loading etc.

 

[smkdan]

NTM: if you could look into that, that'd be awesome. It needs to be a 16bit chip however. Alternatively there can be 2x 8x512K chips. Whatever the case, it must connect to entire 68k data bus, not just 8bits like the current chip does. That's assuming there's no special circuits involved, though. I don't know exactly what you have planned.

A giant ROM set with all game data ever would be ideal, it would reduce the longest load times to a few seconds at worst. 68k will need to bankswitch to get at the data but it's not a big deal for performance. It's the best answer for load times, I just have no idea how feasible any ROM related solution is (can you clue us in?). It won't be legal, but possible and the best solution for performance.

The original SRAM cache idea would work for chunks of data that the system has to constantly load in and out between rounds or something. Like the KOF94 repeated loads between the loads of the actual stages. It won't work for stuff that isn't loaded in/out constantly, that needs a ROM solution. If it can fit in 768KB and is required repeatedly, it'd work.

 

[NeoTurfMasta]

Let me see what I can do about the additional sram. The ROM idea would be cool but that may be a much later on thing. Probably more expensive than its worth, and I really dont have any solution in mind for that, just an idea.

I may start with the memory card interface and just work off of that. I really may need to get a top loader myself. Unless you think any of your sram cache work will be fine on my Z.

 

[smkdan]

Even if the ROM doesn't work out, using the SRAM cache will still help. Even in games that don't really need it as badly. Say in turf, I can already eliminate most of the loading between courses without any modification. With about 150KB of cache, I can eliminate them entirely. The remaining 6 or 7Mbits can be used for more demanding games, although I have to actually research how they work before I can do anything about it.

Here is the current CDZ version that can be used to see if the SRAM cache will work on your unit. It's confirmed good on my toploader. All you need to do is to start any game and press D until you get to the memviewer. Keep pressing right until the cursor on top gets to "BAK" (it's on the second page). Hold A+B to scroll fast and just scroll down. The address on the left should be able to go into 0Fxxxx without resetting the console and you should see the same pattern over and over again. If it resets, then it's a problem. If not, then you have the same 1MB SRAM space allowable as mine and it'll be fine most likely.

 

[Murray]

A giant ROM set with all game data ever would be ideal, it would reduce the longest load times to a few seconds at worst. 68k will need to bankswitch to get at the data but it's not a big deal for performance. It's the best answer for load times, I just have no idea how feasible any ROM related solution is (can you clue us in?). It won't be legal, but possible and the best solution for performance.

If only there was some sort of way to make interchangeable roms. Like boards that you could swap out to eliminate load times entirely. Kind of like how NESes and Segas had cartridges, but much bigger. Man, that would be cool. I bet we could even come up with a way to plug in like 2-6 of them at once and swap between them with a button!



So yeah, the giant rom set thing sounds kind of cool but I think that may be overkill on the Neo CD.

 

[NeoTurfMasta]

Here is the current CDZ version that can be used to see if the SRAM cache will work on your unit. It's confirmed good on my toploader. All you need to do is to start any game and press D until you get to the memviewer. Keep pressing right until the cursor on top gets to "BAK" (it's on the second page). Hold A+B to scroll fast and just scroll down. The address on the left should be able to go into 0Fxxxx without resetting the console and you should see the same pattern over and over again. If it resets, then it's a problem. If not, then you have the same 1MB SRAM space allowable as mine and it'll be fine most likely.

Seems to work fine, with no resetting. Cant seem to dig up a 8Mbit chip anywhere locally, but I'll order a couple this week.

Edit: basically my initial plan is to remove the existing 8x8 sram chip and put a 512k x 16 chip in its place with the remaining lines going directly to the 68k. I may be wayyy off on this, but its where I'll start.

 

[smkdan]

@Murray: turning the neocd into a multicart MVS would've cost far too much anyway. Based on what I see for memory prices that is.

@NTM: That plan seems OK, hoping it all works out. If it causes alot of trouble then I wouldn't bother. This won't be the big fix to the loading problems and in some games it won't really do anything at all. Don't want to give out the wrong impression. If anything the main improvement apart from slightly better loading (depends on game/situation) would be reduced drive activity for prolonged life.

If this actually happens, I'd set aside 1Mbit for save data and the other 7Mbit. Need everything I can get.

 

[NeoTurfMasta]

ordered a couple should be able to install next week. Think the design on the memory card project is pretty much finished. Going to finish up the PCB layout this week and then get pricing together.

 

[Caprica Orange]

This is epic, when this is "finalized" I'll be ordering too!

 

[smkdan]

It's far from finalised, but the extra stuff has to wait for now. Here is the page which I updated a bit. Just to add a few images and a few sections. Also put up the downloads for the current version which works fine as far as I can tell. The major issues are that you can't start with MVS mode in most games and that the cheat DB is only there for a few games. Will add games as I go but most of the major features are already in there.

 

[smkdan]

Could one of the guys with a modded system and pulstar try this and compare a run through the first stage with an older BIOS? If it slows down any less or doesn't work at all it would help to know. Emulator tests showed the slowdown was less severe but I don't have a working real system to do a proper test on.

 

[Sex Machine]

Hey man, how much would you be charging for a bios chip for these? Looked at your page and found the price for the board, but how much for the bios chip?

 

[supergoose]

first post in 3 years and probably 2 months too late, but still...

for the first time in years i went through all of my neo stuff last night and found a top loader mainboard and a complete drive that i kept as spare parts. i could donate both and even cover uninsured postage (~14€), if it would mean that someone would seriously continue to work on this project.

 

[kernow]

 

[smkdan]

first post in 3 years and probably 2 months too late, but still...

for the first time in years i went through all of my neo stuff last night and found a top loader mainboard and a complete drive that i kept as spare parts. i could donate both and even cover uninsured postage (~14€), if it would mean that someone would seriously continue to work on this project.

Thanks but I'm fine for CD hardware. This toploader setup works, it just has some issues that means it can't be enclosed for some reason. It does function though.

It's not a dead project, but I'm not really motivated to add anything outside of a few cheats. It does most of what I want it to do outside of load times, which probably won't be improved.

 

[NeoTurfMasta]

Today I wired a memory card reader to my CDz and it works perfectly. Tried my SaveMasta memory card, no problems. Even tried the original SNK card and again, no problems. Saved some stuff on my CDz, took it to my MVS and it could read it. Took my SonicWings 3 savefile from mvs, loaded it on my CDz and landed on the last level.

No idea if I'll produce a memory card reader for the CD systems. I'm still a little unhappy with how the CD system can be damaged with little to no abuse on its guts. This would make the CD system a good memory card manager though. Load a custom CD with tons of different saves, then bring it over to your MVS system.

 

[GohanX]

I'm not certain an adapter for the CD would be all that practical, but that is REALLY cool. Well done.

 

[Mike26]

Man this is awesome stuff. I need to dig around for my old neo geo cd system. i know its around here somewhere...

Can anyone recommend a good and cheap rom burner preferably usb. It would be an added plus if it could also program MVS bios's.

 

[Warpedflash]

Is this Project still alive?
I would love a decent unibos type bios for the CD just because its actually affordable :P

 

[Xian Xi]

On the NeoCD it would probably be easist to install a mem card reader by cutting a slot on the casing but of course some won't like that.

 

[smkdan]

It's been dead for months now. I took down the page and this thread probably shouldn't be stickied anymore. There's unresolved issues with the BIOS adapter conflicting with the CD drive which makes a custom BIOS impractical.