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Author Topic: Super GameBoy + Color concurrently? just how incompatible are they?  (Read 1784 times)


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Short version: What I'd like to know is just how much of an incompatibility is really there between SGB and GBC other than that there's no existing hardware that combines both, and that, therefore, no existing software is ready for such a hypothetical combination.

Long version: From what I can gather, the SGB basically works as an extension to the original GB's hardware, where the GB software has to communicate with the SGB and send it the borders, palettes and any other special enhancements. It's not that the SGB does all that stuff on it's own because if "finds" it in the GB cart, but rather the GB CPU has to explicitly tell the SGB to do all the stuff. I read the SGB does do some checking of the GB header first and sets some stuff, but still the GB part has to actually send the stuff over.

Now, the GBC couldn't possibly take advantage of any of that, except the color palettes (but then again the GBC had superior coloring than the SGB extensions could offer so Nintendo just scrapped SGB colors on the GBC and made a whole new system), and neither could the SGB run in GBC mode. Knowing that, it makes sense that even games that had BOTH SGB extensions and Color mode were made to run in one of the two mutually exclusive modes. They will run in normal GB mode with optional SGB extensions (borders, limited color pallet es, SNES sound and other tricks) OR in Color mode without any SGB stuff.

BUT I still have a question: While it made no sense for commercial games running in "Color" mode to attempt to use SGB extensions, since no official hardware ever existed combining both functionalities, is there actually any intrinsic insurmountable conflict between the two standards that would prevent coexistence? overlapping addresses? clock incompatibilities?

My curiosity is due to titles like Wario Land 2, Zelda DX, and others that contain SGB extensions and, also, can run in Color mode.
Would it be theoretically possible to make an environment (through hardware or emulation) that offered both Color mode and SGB extensions concurrently?
This would be combined with hacked versions of these games that would run in Color mode and still load, at least, SGB borders, specially for games that have more than one border and change them during the game.
Some emulators attempt to run SGB+C games in SGB mode first until the first border is loaded and then reboot into Color mode, retaining that initial border for all the play session.

Now, I'm not asking for it to be made (though, I'd be very glad to see it).
I guess that with enough time and resources anything is possible and such emu/hardware could be made and games be hacked to use it. But I presume it's a very long shot.
« Last Edit: December 10, 2017, 05:31:28 pm by radorn »


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Re: Super GameBoy + Color concurrently?
« Reply #1 on: December 10, 2017, 05:09:57 pm »
My first thought is what a game like Dragon Warrior Monsters 1 which is designed for GBC but explicitly prevents the multiplayer functionality when run on SGB (at least SGB1, I don't have an SGB2 to test). (as in, it doesn't try it and error out like other games, it's knows to skip the test on SGB)
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Re: Super GameBoy + Color concurrently? just how incompatible are they?
« Reply #2 on: December 10, 2017, 05:38:09 pm »
Could it be because of this?
Super Game Boy 2

Alternate enhancements can be given to games when played using a Super Game Boy 2 adapter, done by examining the internal value of the CPU on start-up: 01 is for normal Game Boy or Super Game Boy and FF denotes Super Game Boy 2. Tetris DX is the only known example, displaying an alternate border. Super Game Boy 2 detection is achieved by examining the internal value of the CPU upon boot-up.

Maybe that game check that and disables the link functionality? No idea.
Or, maybe, it has nothing to do with the SGB: Does multiplayer work on a monochrome GB at all?

None of this clears any of my doubts, though.
« Last Edit: December 10, 2017, 05:46:47 pm by radorn »


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Re: Super GameBoy + Color concurrently? just how incompatible are they?
« Reply #3 on: December 10, 2017, 09:36:52 pm »
i was wondering about this as well, possibly another advantage to having SGB run in GBC mode

the (i think this is right) Killer Instinct GB game used the additional buttons of the SNES controller

so maybe hacks that added buttons (mainly thinking of Zelda LA:DX, Ages, and Seasons for this)

have the 2 item buttons, Y and B (one could be permanently sword)

then map A to the power glove (when near a liftable object) and pegasus shoes ()when not) and talking and opening chests/actions (same as the A button in ALttP)

then map x to be Roc's feather or a "dedicated jump button"

maybe (and this would be so cool) have L and R cycle through the items (except Swords, Power Glove, Pegasus shoes, and Roc's feather obviously. cause they would have their own buttons)

there are plenty of other GB/GBC games that could benefit from having more buttons as well

anyways, just a thought


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Re: Super GameBoy + Color concurrently? just how incompatible are they?
« Reply #4 on: December 11, 2017, 12:43:59 am »
The most comprehensive series of articles I've seen on the SGB is over here:

You can ignore the attention-grabbing article title.  Be sure to read the other articles in the series.
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Re: Super GameBoy + Color concurrently? just how incompatible are they?
« Reply #5 on: December 11, 2017, 11:36:48 am »
Nice article series. The bit about under utilised hardware also makes sense when looking at how a lot of early DS games turned out. I see bomberman multiplayer was mentioned in passing but I want to shine a light on it a bit more -- as far as classic arena multiplayer bomberman goes it is among the best of them. I remember having an emulator with the functionality once and thought I would give it a go as we had rinsed bomberman 64 and the PCE and megadrive versions and was more than pleasantly surprised.

I had a quick scan around last night, though more of a features analysis than a comparative one for the address clashes mentioned in the OP. Might be a few things with the screen modes.

The controls stuff was interesting to read about and might be simpler to play with than I thought (it is some kind of select/cycle inputs affair than extra registers like a more conventional console). That said it would probably not be much different to the normal controls hacks, or arcade extra button via coin slot, either.