Problem with Sega Sega Classics Arcade Collection

[Former user]

Fist of all, i have tested japanese version of this compilation on Wii with Genesis Plus GX 1.7.4. Game - Streets of Rage.

Result - it crashed at boss from level 5. I've used BIOS from Model 1.

Yesterday i've tried BIOS from Models 2 (NTSC-U and NTSC-J) and two images of compilation - USA and Japenese respectively. Version of emu - 1.7.5 RC1.

Result - black screen after loading game image.

[Eke ekeeke]

I cannot reproduce your latest issue with the latest version (available here), tested fine USA, PAL and Japanese version of the game using Model 1 and Model 2 BIOS.

If you don't even see animated BIOS intro after loading the game image then those are either invalid game image files or invalid BIOS files. What are the filenames of the game image files ? Do other CD games work with these BIOS ? How did you made the emulator pick those BIOS ? Did you use the system setting that let you change BIOS inside the emulator to select new ones from ROM browser or did you just overwrote default ones (BIOS_CD.U.bin and BIOS_CD_J.bin) in /genplus/bios directory ? You didn't renamed .zip files you downloaded into .bin files, right ?

As for the crash at level 5 boss in Streets of Rage, I will need a savestate before the occurrence of the bug (or at the start of the level) for verifying that one. What kind of crash did you get ? Black screen but emulator menu still accessible ? Frozen Wii? Wii Exception screen with digits all over the screen ?

In general, try to give as many details as possible when reporting issues.

[blaze-f]

Here are savestates.

I've used images:

Sega Classic Arcade Collection - Limited Edition (1992)(Sega)(NTSC)(JP)[!][compilation][G-6012P-00024-2-R2M]

Sega Classics Arcade Collection (1992)(Sega)(NTSC)(US)[!][compilation - 5 games][CDAC-056800 2]

converted to bin/cue and renamed

[blaze-f]

I converted my images from iso+wav to bin+cue - now both of them work. Other games also work with BIOS'es that i use.

Tried latest version of emu. Same result - game frezes before boss fight. Emu menu stay accessible.

Also i've noticed many slowdowns during the game. Especially on 3rd round.

About giving many details - sorry, i'm from Russia, and my english is not as good as i would like. It's hard to explain certain things.

[Eke ekeeke]

Thanks, I managed to reproduce the freeze at level 5. Not sure yet how i'm going to fix it but I identified the problem. It's caused by some synchronization issue between Megadrive and Mega CD CPUs where the two end up waiting for each other and lock the game.

[blaze-f]

Thank you. And what about slowdowns during gameplay? Do you need savestate for round 3?

[Eke ekeeke]

I didn't notice any particular or odd slowdown while playing, in round 3 or others. Is there something specific to look for in round 3 to notice it?

It's normal there is some slowdown when there are many sprites on screen and also during some transitions when the game is loading new data from CD (contrary to cartridge version where whole ROM is accessible at once).

[blaze-f]

->> It's normal there is some slowdown when there are many sprites on screen

Yes, I mean it.

Unfortunately i can't test it right now on my own Mega CD2. But i found this video

https://www.youtube.com/watch?v=1ZIpZC4Bm7k

This guy plays it on real hardware. And i didn't notice any slowdowns in this video.

[Eke ekeeke]

Do you mean it is generally slow or there are some slowdowns at some fixed points ? If so, when exactly ? I played it until end of round 5 and did not notice any particular slowdown.

Anyway, the round 5 boss lock issue has now been fixed in https://bitbucket.org/eke/genesis-plus-gx/commits/56f3d64265b33ad654d24f44b76d7b37af525e38

For the record, it was not a synchronization issue between Main-CPU and Sub-CPU as I initially thought but rather the Sub-CPU trying to clear a read-only communication register initialized by Main-CPU. Those writes were allowed by the emulator for optimization but on real Mega CD, writes to these registers from Sub-CPU should be ignored.

[blaze-f]

I'm not exactly sure, are they fixed at some points or appear randomly.

Anyway, they are not critical for me personal.

Thank you very much for fix round 5 boss lock issue.

[Eke ekeeke]

I am closing it then since I couldn't find anything odd in emulation tracelog or anything slowing down unexpectedly.