GB Core / SGB Core Confusion

[BraveToaster]

Hi,

I started playing around with the Game Boy, Game Boy Color, and Super Game Boy cores today, and sorry if this is a silly question (I'm new to MiSTer), but I'm pretty confused as to what core can do what.

• Is the "Game Boy" and "Game Boy Color" core actually the same? It seems both can load GBC games fine and show the right colors.

• The "Super Game Boy" core is actually an SNES core, right? Seeing that it is very different from the others and doesn't have savestate support.

Now, when I take a GBC color game like Zelda: Link's Awakening DX or Shantae, I see...

• The game works fine (with colors) in either the GB or GBC core. However, running this on a 15 kHz CRT, the screen flashes every time the scene changes (kind of an up/down movement as if the CRT has to re-sync), e.g. every time I hit "Start" at the beginning of Zelda. I also do not get a border for the game, but I can load one from a file. I don't see any option to get the border that belongs to the game.

• In the SGB core, I immediately get the Zelda border, but the game is shown in monochrome, I do not get the GBC colors. On the upside, there's no screen flashing when the scene changes. Shantae just informs me that this is a GBC game and won't run on a regular GB.

Am I doing something wrong? Should the SGB core support GBC games or is this strictly GB only?
What's up with this screen flashing in the GB core - and why do I not get the right border?

Thanks for your help!

[BraveToaster]

I managed to find some of the answers by myself, sorry for not looking enough first:

• Yes, the SGB core is SNES-based. There's actually another thread that details that... silly me.

• In the GB core, under Audio/Video there is "Stabilize video(buffer)". Setting that to on fixes the screen issue.

What I'm still not sure about is...

• Should the SGB core actually support GBC games, and if so: how do I activate that?

• Shouldn't the game border show up in the GB core?

[AngelicLiver]

Hi, welcome to all things MiSTer.

No, the Super GameBoy does not support GameBoy Color. Neither does the core.

You can set custom borders as outlined here in the GB/GBC core.

I would highly recommend you read through the wiki.

[BraveToaster]

Thanks! I know how to set custom borders in the GB, and that actually works fine for me . What I'm wondering about is why the game-specific border doesn't show up, since it does in the SGB core.
I've seen the wiki and read through quite a lot of it, but it is a bit short on core-specific information. It's only the README.md for each core, right? So I couldn't find answers to these questions anywhere in the wiki.

[Sterbi]

If I remember correctly, GB core adds custom borders only as an overlay, it's not able to read border data from ROM, while SGB loads it from ROM as on real SNES with SGB.

Super GameBoy doesn't support GameBoy Color, but there are some GBC games which have been released with backwards compatibility with original GameBoy (that's why you are able to load Link's Awakening DX or Shantae but in non-color mode). Those have been released in black non-transparent cartridge, instead of transparent like with GBC-only games.

[paulbnl]

What I'm wondering about is why the game-specific border doesn't show up, since it does in the SGB core.

Because the game starts up in GBC mode when System is set to Auto and the Super GameBoy only supports GB games.

As a work around you can load the game with System set to Gameboy, wait for the border to appear and then load the game with System set to Auto or GBC.

[BraveToaster]

As a work around you can load the game with System set to Gameboy, wait for the border to appear and then load the game with System set to Auto or GBC.

That actually works, thank you! So: Set the system to Gameboy, load the game, wait for the border to appear, set the system to Auto and reload. The border stays, the game is in GBC mode.