Mega-CD/Sega CD FPGA Optical Disc Emulator

[Greg2600]

Yeah we plan to do a overhaul on the menu system and font of the SSDS3. Basically back port some of the design elements (the icons to represent type of game, font) from MegaSD. Hopefully that happens this summer.

That will be much appreciated!

[Pyron]

Yes to both!

Nice to rear it, its cool show some footage about it to show how it perform.

Yeah we plan to do a overhaul on the menu system and font of the SSDS3. Basically back port some of the design elements (the icons to represent type of game, font) from MegaSD. Hopefully that happens this summer.

Cool, disable the sounds in menu also can be include in options menu,
also menu on SMS / GG converted games could to be implemented

As far as load time goes, it's similar or slightly faster than real hardware. This is done to maintain compatibility with Genesis and Mega Drive consoles. You can only fudge this kind of stuff so far before you run the risk of having game compatibility issues.

We understand that, but its not a rule for every system(some of them are vastly improved) so a proper comparison or explanation is cool because its a import aspect of any cd system, any second gain in load times is an improvement.

Also, the comment about CDDA audio being inferior to a real CD unit. This isn't exactly the case. If you were to rip a cdda audio track from a game in your computer and then compare it with a recording of the audio from a console with the MegaSD and from the same console with a SegaCD, you will find that the MegaSD cdda audio matches the ripped track virtually identically. However the Sega CD capture will have a slight treble increase as those units have some type of artificial treble boost.

The complains are legit because they compared it with the real hardware and how they hear the final sound after dac / HW mixing, so the MCD did a better job on audio treatment.

And one last thing: There have been some comments about the PCM audio on the MegaSD sounding a little too clean. We have spoke with Ace and are testing along with FirebrandX a new low pass filter for PCM audio that is identical to what Sega CD hardware has. We will probably add that as an option in the Options menu for people so they can toggle it off and on depending on their preference.

Nice feature

Also one suggestion:

I will would love see the main menu flaps to "cartigdes" and "cd-Rom" like on Super SD system 3

[Flygon]

Odd question - Just how does the "Mode 1" feature work in implementation?

I know that's a strange question, but I am curious if there would be an API for a homebrew cartridge to select a specific disc to be loaded from this flashcart, assuming it's plugged into the Expansion Slot adapter. Or if there's even just a way for the cartridge to "remember" a disc image to boot, if the cartridge tries to access the CD drive.

[chilled]

Does the Mega SD support the Super Street Fighter II mapper (32M+8M) and does it support the 10M Flatmapped rom support used by a lot of Russian Mortal Kombat hacks?
Because I need my MK hacks!

What's the rom limit on non mapped rom hacks? Also Pier Solar and its custom mapper?

[broken]

What's the rom limit on non mapped rom hacks? Also Pier Solar and its custom mapper?

Yes, Pier Solar is supported as is the optional music CD.

[Vector]

Hi Guys. I'm Todd from Terraonion.


Just a couple comments that I am seeing here in this thread.


As far as load time goes, it's similar or slightly faster than real hardware. This is done to maintain compatibility with Genesis and Mega Drive consoles. You can only fudge this kind of stuff so far before you run the risk of having game compatibility issues. While emulators might have instant-ish load time, you have to be careful when interfacing real hardware. Also, all the videos posted above to our channel was captured by me. They give you a good idea of real world performance with the MegaSD. I seriously doubt anyone will be displeased with load times.


Also, the comment about CDDA audio being inferior to a real CD unit. This isn't exactly the case. If you were to rip a cdda audio track from a game in your computer and then compare it with a recording of the audio from a console with the MegaSD and from the same console with a SegaCD, you will find that the MegaSD cdda audio matches the ripped track virtually identically. However the Sega CD capture will have a slight treble increase as those units have some type of artificial treble boost.

We worked with FirebrandX closely to get the audio as accurate as possible.

He even tweeted yesterday about the CDDA audio on MegaSD:
https://twitter.com/FBXGargoyle/stat...16426119684097


And one last thing: There have been some comments about the PCM audio on the MegaSD sounding a little too clean. We have spoke with Ace and are testing along with FirebrandX a new low pass filter for PCM audio that is identical to what Sega CD hardware has. We will probably add that as an option in the Options menu for people so they can toggle it off and on depending on their preference.


We learned a lot from Super SD System 3 and our goal is to make the MegaSD the very best it can be.

I saw a lot of comments about Batman Returns and other ISO being a bit fast compared to originals, you mentioned a firmware update in those youtube comments, will that fix all the ISO in MegaSD errors before being shipped? (Batman Returns looked like it was running at 10% speed or at least cut scenes)

Also, can you upload Outrun cart with CD audio so we can hear better.

[broken]

I saw a lot of comments about Batman Returns and other ISO being a bit fast compared to originals, you mentioned a firmware update in those youtube comments, will that fix all the ISO in MegaSD errors before being shipped? (Batman Returns looked like it was running at 10% speed or at least cut scenes)

Also, can you upload Outrun cart with CD audio so we can hear better.

Dialing back game speed isn't an issue. We of course are working to continue polishing all of this so that when the units ship it will be the best it can be. Inevitably folks will find bugs and we will fix them.

I'll see what we can do to get a video for the Outrun with enhanced audio.

[roce]

@broken
Please comment on the source code situation, where it looks like your product is using both GPL'd code and code that requires a patent license.

[Vector]

Dialing back game speed isn't an issue. We of course are working to continue polishing all of this so that when the units ship it will be the best it can be. Inevitably folks will find bugs and we will fix them.

I'll see what we can do to get a video for the Outrun with enhanced audio.

Thank you, appreciate the reply and look forward to Outrun w/ CD audio video as video reviewers didn't elaborate on that enough IMO. I also like this video I linked below, perhaps from a team member or video reviewer? Load times are cool with me =) Also, thank you guys for making this product =)
https://www.youtube.com/watch?v=S6YMxDBOmCM

[Barone]

Lots of answers

Thanks a lot for taking your time to reply to us here.

Mega SD looks very interesting and I think it's very nice to have an alternative to the original units which are rather expensive and falling apart at this point. I believe Arcade816 project will be using it, for an example; very cool.
From the perspective of someone using CRTs it seems far more interesting than the Mega SG 'cause I can keep the rest of my setup intact.

I have a few questions about it (if they've been answered somewhere else, please, forgive me):
- Did you test Duke Nukem 3D's save with Mega SD? I'm asking because that game uses a bit unusual save RAM size IIRC and some Everdrive MD revisions don't work properly with it. You seem to have saved successfully but then it fails to load your save.


- Do the EEPROM save-based games such as NBA Jam TE (bigger list here: http://www.sega-16.com/forum/showthr...l=1#post619874) require hacking/conversion to battery save to have their saving system working or are they all going to work without any additional trouble for the Mega SD owner?
I'm not talking about save sates.


- Does Mega SD allows you to control Mega Drive/Sega CD volume balance? I mean, games such as Space Adventure Cobra (Lords of Thunder is another offender) have very loud YM2612 instrumentation and if you don't have the Mega Drive 1's volume slider to control it you can barely here the voice overs in the game.
Furthermore, would it be possible to control PSG and FM volume levels independently? That would be one of my wet dreams.


- MSU1 like feature is interesting but is there any chance of implementing something that would make it feasible to re-route Mega Drive games PCM playback to use the Ricoh RF5C164 instead? I think there are far more MD games with garbled PCM playback than games with poor music (not that I wouldn't be enjoying the hell out of MSU1 like support).
Games using SMPS Z80 audio driver usually have really shitty PCM playback, such as Art of Fighting. Being able to play them with decent PCM audio quality would be awesome.


- MD-side overclock breaks Sega CD compatibility when using real hardware. Any chance of Mega SD being more robust/tolerant to it?
I mean, it would allow us to play games which run off the MD's 68000 such as Sonic CD without slowdowns.


Thanks in advance.

[Wesker]

I'll see what we can do to get a video for the Outrun with enhanced audio.

Have you only done enhanced audio tests with OutRun or is there any other already hacked game we can see?

This is the feature that interests me the most about the MegaSD. So many Mega Drive games with shitty audio need to be fixed this way.

[Sik]

- MSU1 like feature is interesting but is there any chance of implementing something that would make it feasible to re-route Mega Drive games PCM playback to use the Ricoh RF5C164 instead? I think there are far more MD games with garbled PCM playback than games with poor music (not that I wouldn't be enjoying the hell out of MSU1 like support).
Games using SMPS Z80 audio driver usually have really shitty PCM playback, such as Art of Fighting. Being able to play them with decent PCM audio quality would be awesome.

That's something that would need hacking the game to change the sound driver (incidentally, that'd make it work on the real Sega CD as well, so it wouldn't be unique to Mega SD).

- MD-side overclock breaks Sega CD compatibility when using real hardware. Any chance of Mega SD being more robust/tolerant to it?
I mean, it would allow us to play games which run off the MD's 68000 such as Sonic CD without slowdowns.

Only way I could see that working is by overclocking the CD's 68000 by the same amount proportionally :​/ (since the problem is with games that instead of doing proper handshake they just assume the other CPU is ready by the time they get around to passing the data)

I guess the question would be whether Mega SD allows overclocking then?

[nihilblack]

I'll see what we can do to get a video for the Outrun with enhanced audio.

That was showed on the presentation, timestamp 30:51.

https://youtu.be/8fE0GR9prQE?t=1851

[segasonicfan]

I'm very disappointed with TerraOnion's business practices with this new product. Their sale page is some of the most misleading stuff I've ever seen for a retro adapter. Collecting $260+ pre-orders they failed to mention:

1. It doesn't work with CDX, X'eye, Wondermega, Laseractive, Aiwa Mega CD, or any Genesis that has the CD portion built in.

2. The CD emulation does not work if a Sega CD is plugged into any Genesis physically.

3. The CD emulation does not work if you are using the 32X.

4. the Sega Nomad is advertised as working with it. But Terra Onion fails to mention that you need to open it up and do modifications. (They also avoid mentioning the Genesis 3 needs internal modifications)

5. Virtua Racing doesnt work (careful wording would have you believe that every Genesis ROM works).

6. The PCM and SMS FM audio sound *way* different in this comparison video, since they are missing filters that the original hardware has. Maybe they'll make an update for that later though.

I don't mind that it's expensive, and I can tolerate that it has these problems and missing features. But misrepresenting an expensive product like this when they know that there are incompatibilities is problematic.

I'm super excited that FPGA development like this is happening. I'm super excited about the engineering work that Terra Onion is doing. But this business practice is dishonest. I almost ordered one, and boy would I be so pissed if I found out later that CD emulation wouldnt work on my Sega CDX after plugging it in.

I'm concerned that this is becoming the norm for retro gaming gaming companies. Put your product up for sale and while the hype is high collect a bunch of non-refundable pre-orders before full product information is revealed. :/

Big shout-out and thank you to RetroRGB for documenting everything in his amazing video. You have to watch it if you're going to buy this product:
https://m.youtube.com/watch?v=iACMZfhx1Ms

[broken]

I'm extremely disappointed with TerraOnion's business practices with this new product. Their sale page is some of the most misleading stuff I've ever seen for a retro adapter. Collecting $270 pre-orders they failed to mention:

1. It doesn't work with CDX, X'eye, Wondermega, Laseractive, Aiwa Mega CD, or any Genesis that has the CD portion built in.

2. The CD emulation does not work if a Sega CD is plugged into any Genesis physically.

3. The CD emulation does not work if you using the 32X.

4. the Sega Nomad is advertised as working with it. But Terra Onion fails to mention that you need to open them up and do modifications. (They also avoid mentioning the Genesis 3 needs internal modifications)

5. Virtua Racing GEN doesnt work (careful wording would have you believe that every Genesis ROM works).

6. The PCM and SMS FM audio sound *way* different in this comparison video, since they are missing filters that the original hardware has. Maybe they'll make an update for that later though.

I don't mind that it's expensive, and I can tolerate that it has these problems and missing features. But misrepresenting an expensive product like this when they know that there are incompatibilities is really not ok.

I really dislike that it's becoming the norm for retro hardware developers to intentionally mislead customers by either misrepresenting their products or withholding important compatibility information.

I'm super excited that FPGA development like this is happening. I'm super excited about the engineering work that Terra Onion is doing. But this business practice is dishonest. I almost ordered one, and boy would I be so pissed if I found out later that CD emulation wouldnt work on my Sega CDX after plugging it in.

Big shout-out and thank you to RetroRGB for documenting everything in his amazing video. You have to watch it if you're going to buy this product, since it has all the information Terra Onion isn't telling us:
https://m.youtube.com/watch?v=iACMZfhx1Ms

I am sorry, but you are 100% wrong about us not mentioning any of this.

On our product page for the MegaSD, we have a link to the manual.

https://downloads.terraonion.com/pub...ser_manual.pdf


That manual clearly details compatibility with different hardware and even has a well laid out grid that breaks down what is supported on each hardware.


We published this manual ahead of time to specifically avoid confusion.


And as far as Virtua Racing goes, we intend to add support for the SVP chip at a later date.


We are being as transparent about all of this as we can be.