How Does the Super Gameboy Work?

[TMNTSPYVSSPY]

This has been bugging me for a while, and the only answer I can get is "it's a Gameboy in a cartridge." That doesn't make any sense though, because the snes pin out for carts doesn't have a video port, or audio if I'm remembering correctly. That's why all those 3rd party adapters that have come out recently have alternative AV cords. So in theory, the Super Gameboy would just strap on to the nonexistent AV pins, but since they aren't a thing, it just doesn't seem like it should work. If you can help answer this, that would be much appreciated

[SuperDerpBro]

I'm pretty sure Farore, Nayru, and Din have something to do with it. Nintendo is very hush hush about stuff like this though.

[theclaw]

It's clearly mixed into the SNES video, but the question of how I'm not sure off hand.
You'll notice that Super Gameboy's drawing tool can add a layer of stuff on top of the Game Boy image.

Perhaps the best part of this is unmodded 15khz RGB. Gamecube's player lacks official 240p, and you'd need either a PAL system or the component cable for RGB quality potential.

[Tanooki]

I was under the impression the tall cartridge inside is a mix of a SNES cart and the Gameboy architecture and actual processor. The SNES side has its own software ROM chip with the tools of the SGB and its boot process along with the other abilities we know from displaying borders, better sounding audio bits, and visual queues that it reads when they're sent from the GB side of things from the SGB cart. The GB inside there I think was the z80 chip of the original along with the other necessary bits, clearly missing the video output since there's no LCD there and instead with the software on the SNES side translates the imagery through their own GB emulator and coughs all the stuff up they wish you to see on screen. Since the GB hardware is covered by Nintendo legally and can't be duplicated in a legal sense at the time nor even now with stolen tech docs, those who tried had to attempt to reverse engineer it. Given they didn't have a GB boot rom or the rest, they had the ability to fire up a game, but for the a/v they had to bypass it through the RCA cable off the side into another set of jacks on the TV much like a standard off the rack Jakks (etc) TV games system.

So it would like GB/SGB game -> Gameboy inside cart parts/code --> handshakes --> SNES boot code and other processes and gameboy emulator of sorts --> outputs to TV through SNES.

I could have sworn I've seen some tech doc break this down on gamefaqs or some dev page before in the past. I know there were attempts to get this thing to work in emulators over the years. And I have seen the SGB cart itself booted up, but it was like a decade ago and back then that worked by no one could figure out how to attach a GB game to the ROM or otherwise get around that to fire up a game on it that way.

EDIT: I'm reading through some dated development stuff from a decade ago and the short answer is that the SGB is a real gameboy on board and then there's the SNES chips with the software that interprets the games for the SNES to output them which also will have calls to pull and display borders, color choices, extra sound effects and visuals. The most extreme normal one would be Donkey Kong by Nintendo, but the most over the top was Space Invaders which has the original, the colorized one(like the overlays on the arcade) and then a SNES version with enhanced audio and visuals all on one cart.)

Also this from the wikipedia: "The Super Game Boy actually consists of the same hardware as the Game Boy; inside the cartridge is a separate CPU that processes the games while the Super NES only provided means for user-input, output of graphics to the screen, and the additional coloring, similar to the Atari 5200 version of the Atari 2600 adapter.

The original Super Game Boy is known to play the game program and its audio 2.4% faster than other Game Boy hardware. This is due to the use of the Super NES's clock speed divided by 5, which ends up being 4.295 MHz instead of 4.194 MHz.[4] The timing issue can be rectified by adding an appropriate crystal to the Super Game Boy and disconnecting the Super NES's clock source."

[Cronozilla]

This has been bugging me for a while, and the only answer I can get is "it's a Gameboy in a cartridge." That doesn't make any sense though, because the snes pin out for carts doesn't have a video port, or audio if I'm remembering correctly. That's why all those 3rd party adapters that have come out recently have alternative AV cords. So in theory, the Super Gameboy would just strap on to the nonexistent AV pins, but since they aren't a thing, it just doesn't seem like it should work. If you can help answer this, that would be much appreciated

It just has the GameBoy inside the cartridge and passes instructions for rendering and receiving controls through the SNES. There's actually a timing issue with the machine because it uses the SNES' clock as a base. Likely to keep the devices in sync.

It just reads control input as any SNES game would, and passes render data through the cartridge connector like any SNES game would, but it handles the actual processing inside the cartridge with the actual gameboy hardware.

Other similar types of systems can achieve this kind of functionality, because they usually have similar (or identical) chipsets. Like the Master System and Genesis (and Colecovision and ZX Spectrum)

[SuperDerpBro]

Wasn't the timing issue fixed in the Japanese version?

[alienjesus]

Wasn't the timing issue fixed in the Japanese version?

It was in the Japan-only Super Game Boy 2. Japanese Super GB 1 has the timing issue.

[Cronozilla]

Yes, it's not a complicated problem it needs an extra crystal so it has its own clock. I'm not sure if a mod on Super Gameboy is complicated or not. But yes, as alienjesus said, the Super GameBoy 2 in Japan had this issue removed (since they added a crystal).

[GSZX1337]

This video shows the opening of a Super Game Boy and the man behind the camera goes over what each chip is and its function.

[Tanooki]

Now that's a handy video, starting to think I shouldn't have explained things and just wrote 'it works' given the response.