Poll of the Day > some question about the cpu of gameboy color

(+) Yeah! (+)

it has two modes, single 4 or double 8. when does it run in single mode and when in double mode?

I would imagine it runs in double 8 when playing GBC only games, and single 4 when playing regular gameboy games.
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Zareth posted...

I would imagine it runs in double 8 when playing GBC only games, and single 4 when playing regular gameboy games.

what about the regular gbc games?

Single 4 (which is 4.19 MHz) runs exactly the same as the CPU in the original Gameboy, so it runs in that mode when it detects an original Gameboy cartridge.
It runs in Double 8 (which is 8.388 MHz) when it detects a Gameboy Color game.
If the game is GBC exclusive or BC with the old Gameboy got nothing to do with it.
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Foppe posted...

Single 4 (which is 4.19 MHz) runs exactly the same as the CPU in the original Gameboy, so it runs in that mode when it detects an original Gameboy cartridge.
It runs in Double 8 (which is 8.388 MHz) when it detects a Gameboy Color game.
If the game is GBC exclusive or BC with the old Gameboy got nothing to do with it.

which mode does a gameboy color run in when it detects a gameboy color game backward compatible with the gameboy?

jjgg123 posted...

Foppe posted...

Single 4 (which is 4.19 MHz) runs exactly the same as the CPU in the original Gameboy, so it runs in that mode when it detects an original Gameboy cartridge.
It runs in Double 8 (which is 8.388 MHz) when it detects a Gameboy Color game.
If the game is GBC exclusive or BC with the old Gameboy got nothing to do with it.

which mode does a gameboy color run in when it detects a gameboy color game backward compatible with the gameboy?

That is what his last line is addressing. Regardless of if it is backwards compatible or not, it will always run in Double 8 .

rjsilverthorn posted...

jjgg123 posted...

Foppe posted...

Single 4 (which is 4.19 MHz) runs exactly the same as the CPU in the original Gameboy, so it runs in that mode when it detects an original Gameboy cartridge.
It runs in Double 8 (which is 8.388 MHz) when it detects a Gameboy Color game.
If the game is GBC exclusive or BC with the old Gameboy got nothing to do with it.

which mode does a gameboy color run in when it detects a gameboy color game backward compatible with the gameboy?

That is what his last line is addressing. Regardless of if it is backwards compatible or not, it will always run in Double 8 .

does that mean if a gameboy color and an old gameboy played the same gbc game, the gameboy color would run the game twice as fast?

you wouldn't detect any performance differences
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HellHole_ posted...

you wouldn't detect any performance differences

why?

Because they programmed the game to run on an ordinary Gameboy and only used the extra power for colors and eventual GBC exclusive stuff.
I cant think of anything like that, but I know that the Oracle Zelda games had features that only worked if played on a Gameboy Advance, and nothing really prevents it from working on GB/GBC as well.
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Wait a minute, there were GBC games that could be played on the original GB?


Oh, is that the black cartridge ones? Because the Oracles are not such games.

DorkLink posted...

Oh, is that the black cartridge ones?

Yup.
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DorkLink posted...

Wait a minute, there were GBC games that could be played on the original GB?


Oh, is that the black cartridge ones? Because the Oracles are not such games.

Didn't Pokemon Gold and Silver do the same? Then Crystal released as GBC only? I think.
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Pokemon Gold and Silver were BC with the grayscale Gameboy.

I used Oracles as example of how it could be done.
Links Awakening DX is BC with the original gameboy, with the Color-exclusive dungeon fully working, but you couldnt see the colors which made it harder.
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As far as I can tell there's a specific register that can be set to switch between the two modes:

http://problemkaputt.de/pandocs.htm#cgbregisters

FF4D - KEY1 - CGB Mode Only - Prepare Speed Switch
This register is used to prepare the gameboy to switch between CGB Double Speed Mode and Normal Speed Mode. The actual speed switch is performed by executing a STOP command after Bit 0 has been set. After that Bit 0 will be cleared automatically, and the gameboy will operate at the 'other' speed.

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If I recall correctly, they actually, like, had two separate versions of the game on the cartridge: a Game Boy version, and a Game Boy Color version. It would check which it was plugged into when booting up and load the appropriate version.

And on top of that, there was a game which actually has TWO completely different games depending on whether you plugged it into a GB or GBC game. I can't remember which game that was though, and really need to look that up. It isn't well-documented.
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Dragon Quest Monsters 1 could also be played on both, but not sure if it had a unique Super Gameboy theme (some games did)
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Oh, here we go! Conker's Pocket Tales are two different games on GB and GBC. They're likely very similar in design, but there are extremely noticeable differences. Even the room you start the game in has a completely different layout.

https://www.youtube.com/watch?v=Mh-2FY9mSZM

https://www.youtube.com/watch?v=lCCsWp-7pa4

And I don't think Conker was the only game to do this.
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Conker's was the game where the GB and GBC game are different.
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Gamechamp3k posted...

If I recall correctly, they actually, like, had two separate versions of the game on the cartridge: a Game Boy version, and a Game Boy Color version. It would check which it was plugged into when booting up and load the appropriate version.

And on top of that, there was a game which actually has TWO completely different games depending on whether you plugged it into a GB or GBC game. I can't remember which game that was though, and really need to look that up. It isn't well-documented.

are there only differences in graphics or there's even more?

jjgg123 posted...

Gamechamp3k posted...

If I recall correctly, they actually, like, had two separate versions of the game on the cartridge: a Game Boy version, and a Game Boy Color version. It would check which it was plugged into when booting up and load the appropriate version.

And on top of that, there was a game which actually has TWO completely different games depending on whether you plugged it into a GB or GBC game. I can't remember which game that was though, and really need to look that up. It isn't well-documented.

are there only differences in graphics or there's even more?

See the videos of Conker above. The games have totally different layouts. The graphics are actually one of the things not very different.
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Foppe posted...

Because they programmed the game to run on an ordinary Gameboy and only used the extra power for colors and eventual GBC exclusive stuff.
I cant think of anything like that, but I know that the Oracle Zelda games had features that only worked if played on a Gameboy Advance, and nothing really prevents it from working on GB/GBC as well.

it needs 4 mhz to handle the colors?