Debug for NeoCD

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
I SHOULD be getting the smd adapter in today for the TL bios. In other news, I am getting the 5 PCB run of the "minimal solder" bios adapter in tomorrow. I'll get one assembled and post some photos. This all-in-one design has been changed back to one board for MVS and one for CD. Looks like my original design might get in the way of 1B's slot riser. Its still the same design, just doesnt feature two slots for chips.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
Anyone willing to let me borrow their Top Loader for some testing? I'll mod it for the new bios for free and throw in one of my bios adapters once they are complete. The spare top loader board I have has issues. I'll also pay return shipping. Can anyone live without theirs for a while?
 

Murray

Akari's Big Brother
Joined
Aug 16, 2005
Posts
2,533
Anyone willing to let me borrow their Top Loader for some testing? I'll mod it for the new bios for free and throw in one of my bios adapters once they are complete. The spare top loader board I have has issues. I'll also pay return shipping. Can anyone live without theirs for a while?
Actually, yeah. You can borrow mine. PM me.
 

Deuce

Death Before Dishonesty, Logic Above All,
Joined
Feb 13, 2002
Posts
7,454
Oh, wow. Hey, smkdan, do you think that memory viewer would help with figuring out those unprinted text lines in SSRPG I told you about?
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
Oh, wow. Hey, smkdan, do you think that memory viewer would help with figuring out those unprinted text lines in SSRPG I told you about?

If this helps in your translation, I'm willing to mod your system for the bios. My donation for the cause :)

And thanks for the help Murray!
 
Last edited:

Deuce

Death Before Dishonesty, Logic Above All,
Joined
Feb 13, 2002
Posts
7,454
If this helps in your translation, I'm willing to mod your system for the bios. My donation for the cause :)

I don't have a CD system, actually. I only use emulators for NeoCD stuff. My particular reason in the debug stuff is because there are specific scenes in SSRPG that are voiceover-only, but there is actually text (subtitles) loaded into memory, yet they aren't displayed. I figure there likely is a relatively simple means of getting it to display, but since I'm not an ASM hacker, I can't figure it out on my own. No NeoCD emulator has a debugger, so this is the only way I can imagine that this little hurdle will be overcome.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
I'll check out the toploader BIOS tonight and should have an update soon after that. Once the top loader stuff is sorted then my setup can make 3 debug BIOS files simultaneously so everything should be supported.

@Murray:thanks for contributing,this shouldn't take long. When the first compatibility test checks out, future releases should be fine unless I make typos in the source.

@Deuce: It would help with emulators that don't have debuggers, Neoraine does have one though it's just crash prone for some reason. Most of the features lead to certain or random crashes so I can't use it as well as I hoped. The features are there,just can't use them. It has a search memory function that might help though (assuming no crashes here). If the program for the subtitle text is already present in the game it shouldn't be hard to enable it, the work is mostly figuring out how it works, where it is and where the text and script are. This debug BIOS will definitely help with that though.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
This should work on all 3 systems, but I can only sort of test the Z BIOS. The other 2 are untested but I disassembled them to check if I didn't miss anything, didn't look like it. Murray's top loader definitely hasn't arrived yet so only the Z and F BIOS files are testable right now. I will start messing around with the load times after I get confirmation that it works on the front/top loader.

slightly off topic: are there any compatible lasers that would work in a CDZ? The RCTRH8147 is readily available online (just costs alot) and is supposedly compatible with the older models. What about the Z, though? Would help to know the part # on its laser assembly. Having readily available replacements for the most failure prone part would be nice.

Also, differences in the implementation between the CD/CDZ would be nice to know. Even if its just a pic of the controller PCB. A site has a pic with a bunch of Sony chips on it including an MCU containing 4KB of undocumented SNK code certainly. The other chips have a clear purpose though and datasheets are available with a little bit of info on them.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
OK, tested the Z bios today and everything seems to be working fine. MVS mode still resets the machine if you enable it immedately after loading. Enabling during gameplay it seems to be fine. This happens on older CD games as well. I use 2020sbb as a test for single loading games and slug 2 for multi. I'll get the frontloader tested tonight and report back tomorrow.

I'm not 100% sure on laser compatability, its been a while since I looked at it, but I could have sworn the TL and Z laser were compatible. I'll also get pics of both Z and TL drive boards posted tomorrow.
 

Rade K

Ned's Ninja Academy Dropout
20 Year Member
Joined
Mar 17, 2001
Posts
11,835
Wow. Cool stuff. Keep it up, guys!

Making NeoCD worthwhile again. Can't wait to see what kinds of cool tricks we're in store for.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
I forgot about MS2 reset issues, the original idea didn't work out. The forced reset program in MVS mode is present in the game, it's just not reachable by the looks of it. It can't be that then and that's the only good idea I had for it. Something else is causing it, don't know what it is since I can't reproduce it with emulators alone. Can't really fix what I can't reproduce. Too frustrating to do by proxy tests. here's a crapshoot though if you're willing to take a few pics:

http://smkdan.eludevisibility.org/ngcd/img/resetinfo.PNG

Power on withthis BIOS, you should see the screen in the top left. Ignore it for now you should be able to press start to get past it. Do whatever required to make the system reset, you'll see the screen again. Take a pic of what you see, then press select to get to the memview it should look something like the top right. I need a pic of each screen, you can hold B + move up/down to flick between pages. I need the area covered by the screen which is 10F300 backwards for 2 or 3 pages. The problem with resets is that some important info is lost so I'm not counting on this for a fix. If this doesn't work it will not be fixed, I don't have the required hardware to do it without wasting alot of time.

Speaking of diagnostics, there is a memory test in the BIOS but it doesn't look accessable without a hack. Has anyone ever seen a memory test error on a regular CD system? The glitches NTM found with the DRAM that wasn't completely functional imply that it normally doesn't test at all.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
There is only 1 thing that could possibly cause that. If this doesn't stop the illegal instruction and strange characters appearing on the reset screen then it will remain unfixed until I get a CD setup. The RAM is being corrupted by something, I made a change that hopefully fixes it.

Atleast the debugging additions help figure out the issues that may pop up now and later,illegal instructions must be caused corrupted RAM here.

Cool drive pics, so they dumped Sony with the later design. The only thing that's clearly common is the motor driving chip. On top loader there is the CD DSP and MCU, I'm guessing the Toshiba and Sharp are the equivalents but there doesn't seem to be an easy to find datasheet on those. Too bad about the lasers not being compatible, without a known source of laser replacements I don't think I will ever buy a Z. Not at the prices they go for.

I also have a theoretically working program for improving front/top loader load times (not by much though) but the emulator crashes when I attempt to test it. So I can't even theoretically verify that it works, no hope there. Will wait until I get my own system.

e: see the market forum in a couple of hours
 

Hewitson

Metal Slug Mechanic
Joined
Mar 6, 2008
Posts
2,198
Incredible work. Just incredible.

How on earth do you and Razoola work out so much about the system? Surely not just by examing disassembled code?
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
For the MVS, most of the info was already publicly covered but a few extra details like the slot selector I had to find myself. In 2002 it must have been a lot worse, I definitely didn't have to do as much work as Razoola in figuring out the neo. For the NGCD it's still pretty bad, I DO have to look at machine code of the BIOS to figure out how the system works because documentation for this doesn't really exist outside of a few notes here and there. There is nothing reliable/comprehensive and I have to rely on NTM's NGCD setups to get feedback from the real thing. Emulation is still shit for this, the BIOS disassembly has been the only good source of info I've had so far.

@NTM: I messed up with a very subtle error in the ROMs above, these should be better. Even if the MS2 reset thing sticks, it would be nice to have the reset diagnostic thing working. I can disassemble MS2 and guess what could be causing it, but it's still a guess. 99% sure it's just something related to backup RAM that doesn't exist, but nothing was immediately obvious.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
I downloaded the updated roms, but there isnt a Z in there. Did you want me to try it on the Front instead?

@everyone - The bios adapter is coming along. I got the boards in, but I am waiting for the TL from Murray to finalize the design. I also have a new 1B coming in so I can get it fully tested on the MVS boards.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
Yes just the front one. Front and top are largely the same, I didn't get the Z finished today.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
Murry's system came in! I'll start working on the TL testing today.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
If you have some time between messing with that top loader, I have a ROM set to confirm something. I'm going to add a POST to the NGCD and I need to detect cold boots. Cart systems can do this easily but a few unknowns about the NGCD mean I can't use the same trick, my method is very cheap. Works in emulators but that never counts for much.

There is actually a memory tester buried in the original BIOS, it is just not accessable outside of hacks. I am making a custom one to adapt to my liking, and to optionally test the system on powerup. It doesn't seem to do any tests normally which is understandable since the cart systems only have about 200KB of RAM to test there as opposed to 7MBytes+. Still would've made sense to add an option for it.

You should get a little message if cold boot is found, then do whatever required to reset the system (don't power cycle) and you should not see that message the second time.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
coldboot.jpg


A few issues here. Font obviously, but also when powering it on w/disc in to wont recognize the game and wont load. Just stays on CD player screen. I can go to memory viewer then exit and it will load the game.

When game does load the debug menu, the menu options appear, but none of the type. Like MVS, English, etc.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
The font fix was simple, the other stuff sounds strange.

There will be no more development until this guy gets a system. Until then the project is on hold.
 

NeoTurfMasta

DANCE DANCE KARNOV!,
20 Year Member
Joined
Jan 18, 2001
Posts
4,229
Okie dokie. A lot of progress has been made in such a short time.

Tomorrow finishes up testing of the bios adapter before the final design is sent to the pcb guys. The CD design is 100% and so far the MVS version seems perfect too. I'll post a new thread with ordering information. To keep costs low the production run will take about 4 weeks till i get the bare PCBs in.
 
Top