Mark III to Game Gear adaptor

[rbudrick]

Hi Folks,

ANyone ever heard of one of these? I know that there were plenty of adaptors to play SMS games on the gamegear, but did Sega ever release one to fit the Mark III carts?

And even more importantly, did the FM sound work when you did?!

-Rob

[Achika]

The official word: No. The unofficial word from curious hackers: I don't
see why not. The NEW unofficial word: No, due to color conflicts. Here's
some information I received (from Meet Mr. Malaria (kyoshiro@netcom.com)):

"As for the possibilility of running Game Gear games on an SMS,
I'd say no, or at least a firm possibility that it can't.

The Game Gear can run SMS carts, of course, but that may very
well be due to intentional downward compatibility of the GG to the SMS,
and such may not work in reverse. The only hardware [difference] I know of
between the two on a chip level is that the GG has a 4096 color palette,
while the SMS has a 256 color palette, but that may be enough. If the GG
has a larger palette, than it must have a different method of setting
each of the color registers than the SMS did: The SMS color can be
determined by one byte, so probably only needed one register, whereas a
number from 0 to 4095 needs two bytes, and therefore the GG chips
probably have two color registers, or one register with a special system
which allows both bytes to be written one half at a time.

The Game Gear was probably designed to allow the color registers
to be set by either the 256 color method (for downward compatibility), or
the 4096 color method, whereas the SMS was created before the GG, so it
would not support a GG-specific game's method of setting colors.

The possible problems resulting from this incongruety -alone-
might be:

#1. A complete crash (if the GG game tried to set registers that did
not exist or had nothing to do with color)

#2. Completely scrambled colors (if the GG uses the same registers
to write the colors, but in a different way)

#3. No picture at all (if the GG writes colors using registers that
had no function in the [SMS], so no SMS color reg would ever be written
to, and all would default to black, so no picture)

It may still be possible that the two are still compatible, but
only [if Sega] intentionally created the GG to set colors in a matter that
would cause the [SMS] to use it's nearest approximation, or if each cart
were programmed to be SMS compatible.

Summary: It looks to me like the GG was designed to be downwardly
compatible with the SMS, but the SMS would not have been designed to be
compatible with the GG."

-- BUT --

From Richard Holbert :
"I don't own either, but I read your FAQ and have an idea that might work.
Aside from the obvious hardware interface problems, the software
incompatibilities could be addressed as follows: I think it should be
possible to rewrite the SMS BIOS ROM (or whatever Sega calls it) to map the
extra color codes to their nearest SMS equivalent.

Source code for both SMS and GG BIOS would be very helpful, but someone
could probably disassemble them."

Someone once mentioned that a pre-Christmas '92 issue of VG&CE contained a
mailorder ad offering a GG to SMS adapter, but my VG&CE collection is
incomplete, and I haven't been able to confirm its existence. Any
information is welcome.

http://db.gamefaqs.com/console/sms/file/sega_master_system.txt

[Ze_ro]

I read somewhere that someone actually had tried this, and the games worked... but the color problems were awful. Everything was random colors, making everything a rainbow. A friend of mine has a broken Game Gear that I've been trying to get my hands on so that I can gut a SMS cart and stick the Game Gear's cartridge port into it. I don't expect to get any better than the rainbow colors, but it's a better fate for the Game Gear than the dumpster.... and no one needs all those Hang-On/Safari Hunt cartridges anyways.

I wonder if there would be any chance at convincing a Power Base Converter to play Game Gear games. Perhaps it has the upgraded hardware that would be necessary. But if this were the case, I would think that Sega would have made their own version of the Super Gameboy out of it.

[Edit: Whoops, my bad... the PBC doesn't really have any real hardware in it at all... this would rely on the Genesis' video chips I suppose]

--Zero

[Ed Oscuro]

No no no.

This is not about getting Game Gear carts to run on a SMS.

This is about a Mark III to Game Gear adapter, a Japanese version of the Master Gear adapter.

The Mark III already had some odd backwards-compatibility things worked in...but either way, I don't see anything at Sega's Game Gear hardware page (http://sega.jp/community/segahard/gg/peri.html), and I see nothing on Google to suggest one exists. I don't see any form of the Master Gear converter, SMS or otherwise. Doesn't mean it's nonexistant, but by the current looks of it...no.

[Raccoon Lad]

There's adapters to play US/Euro SMS carts on Mark III's, but I've never heard of a Japanese version of the Master Gear.

And since the GameGear has the same PSG sound chip as the US SMS (and SG-1000, Texas Intruments, ect.), you wouldn't get FM from a Gamegear.

What sucks is, there's plans online to make a FM circuit for a SMS, but the YM-2413 chips are too hard to acquire for the average hardware hacker (unless you buy in quantities of 1000!).

[rbudrick]

Didn't the guys over at SMSpower.org order them once?

Their boards don't go very far back. That would rock to mod my US SMS for FM sound...I wonder if they got a hold of these chips.

THanks for answering , Racconlad! As for the Japanese Mastergear, I coulda sworn I'd heard of em, but that was before I knew that the Mark III and the SMS had different cart sizes.

-Rob

[rbudrick]

And also, has anyone ever made a Mark III adapter to play them on the SMS? Or vice versa?
-Rob

[Raccoon Lad]

I've seen what appear to be chinese made adapters for playing US SMS games on a Japanese system, and I've seen pics of a similar homemade device.
the problem with playing Mark III games on a US system is the US system's BIOS locks out any game without an international country code in the ROM, and less than half Japanese Mark III games have the international code, and thus, they won't work on a US system unless you replace or disable your system's BIOS.

[rbudrick]

So even if you adjust the jumpers in the system to make it think it is in the Japan region, the US SMS would lock them out?

I'd love to find the plans for one of these...only problem would be getting a spare Mark III cart socket.

-Rob

[Raccoon Lad]

You might be able to add a switch to the logic pin of the BIOS to allow the Mark III games to be played. As for the connector, Sega used fairly standard parts, so finding one to make an adapter might not be too difficult.

But yeah, the "Mark III mode" switch that's on my site will only let you play Woody Pop, and that's because it already has an international country code in the ROM, but has controll issues when played in a US system.

oh, and there's some hard to read pinouts on SMS Power that show how to build a US SMS-to-Mark III adapter that could be adapted to make a Mark III-to-US SMS adapter

[link1110]

Would Mark 3 FM games work on a Genesis Power Base Converter?

[Raccoon Lad]

They'll work on a Japanese Power Base Converter plugged into a US system, but you won't get the enhanced FM sound, just the regular PSG sound.

There's a combination Mark III/ Master System adapter for teh genesis you can buy from one of the major online Hong Kong import stores, but it too won't give you FM sound.