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Maybe some of you know the answers to these :)

Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?)

Does anyone know what GG games set bit 7 of VDP register #0 to stop vertical scrolling for the last two columns of the display? I thought Power Strike 2 did in the second level, but was wrong.

What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely)

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Quote

> What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely)

I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;)

My Homepage

Quote

>
> > What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely)

> I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;)

Well, in fact they are ok on GG.
I can't say however if it uses the same palette as SG-1000/SC-3000 or as SMS.

Quote

> >
> > > What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely)

> > I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;)

> Well, in fact they are ok on GG.
> I can't say however if it uses the same palette as SG-1000/SC-3000 or as SMS.

The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable.

On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio.

Mike

Quote

> The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable.
> On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio.

Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines.
Then. I have yet to find out why.

Quote

> > The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable.
> > On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio.

> Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines.
> Then. I have yet to find out why.

They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too?

Mike

My sister bought a game gear with a pirate cart for her daughter for christmas. It included both SMS, GG, SG1K and MSX games.

Quote

> > > The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable.
> > > On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio.

> > Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines.
> > Then. I have yet to find out why.

> They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too?

> Mike

Quote

> They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too?

Technically, I think that a cartridge that would rewire addresses and ports, and includes an MSX-1 BIOS, should be enough for playing MSX-1 games on SMS.

I'll check how SG-1000 modes operates on GG.

Quote

> Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?)

I tested it now on the three kind of non-Megadrive VDP, and it works fine.

Quote

> > Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?)

> I tested it now on the three kind of non-Megadrive VDP, and it works fine.

Ok, this is good. Thanks for testing!

Like the Y's name table bug, it could have been where the pattern generator base address register would possibly mask the upper bits of the VRAM address when fetching patterns, on the original SMS VDP. If the VDP is emulated like this, Bart vs. Space Mutants had bad tiles on the title screen.
But apparently this isn't the case. In fact, the name table problem might be the only bug of this type with the SMS VDP.

My Homepage

Alright, I've toyed with the GG a bit tonight.
TMS9918 modes seems to be fully supported on the GG, except for the palette which is taken from the usual SMS/GG palette.

I've worked out a little bit of code that can be appended to a SG-1000 game, with minor modification to the SG-1000, and which setup a custom palette then run the game. And it works!
Here is a pictures, running with a palette I made up which looks like the SG-1000 palette, but using SMS colors.

I'll toy this palette a bit, and I think this way I would even be able to figure out the SG-1000 palette used on SMS, I guess it uses SMS colors.

So, back to the pirate cartridges, the only thing they does is to set up a palette on startup (with the main selection menu), and that's it.

Quote

> So, back to the pirate cartridges, the only thing they does is to set up a palette on startup (with the main selection menu), and that's it.

Do sprites still use the sprite palette? Meaning you'd set colors 0-F and 10-1F to the same TMS9918 palette values?

If so, it might be interesting to make the background colors a little darker than the sprite ones, to enhance the visibility. ;)

My Homepage

Quote

> Do sprites still use the sprite palette? Meaning you'd set colors 0-F and 10-1F to the same TMS9918 palette values?
> If so, it might be interesting to make the background colors a little darker than the sprite ones, to enhance the visibility. ;)

Good question.
I tried - everything seems to uses colors 10-1F.

Author	Message
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Questions Posted: Wed Jan 16, 2002 5:25 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Maybe some of you know the answers to these :) Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?) Does anyone know what GG games set bit 7 of VDP register #0 to stop vertical scrolling for the last two columns of the display? I thought Power Strike 2 did in the second level, but was wrong. What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely) My Homepage

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Oops Posted: Wed Jan 16, 2002 5:27 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote > What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely) I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;) My Homepage

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Re: Oops Posted: Wed Jan 16, 2002 7:59 pm
	Quote > > > What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely) > I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;) Well, in fact they are ok on GG. I can't say however if it uses the same palette as SG-1000/SC-3000 or as SMS.

Mike G Joined: 21 Apr 2000 Posts: 598 Location: Newcastle upon Tyne, England	SG-1000 on GG Posted: Wed Jan 16, 2002 10:54 pm
	Quote > > > > > What is the color problem with TMS9918 games running on a Game Gear? Are the colors just darker, or totally off? (like the RGB values were swapped around or missing entirely) > > I had meant SG-1000 or SC-3000 games, which use the TMS9918. ;) > Well, in fact they are ok on GG. > I can't say however if it uses the same palette as SG-1000/SC-3000 or as SMS. The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable. On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio. Mike

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Re: SG-1000 on GG Posted: Wed Jan 16, 2002 11:24 pm
	Quote > The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable. > On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio. Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines. Then. I have yet to find out why.

Mike G Joined: 21 Apr 2000 Posts: 598 Location: Newcastle upon Tyne, England	Re: SG-1000 on GG Posted: Thu Jan 17, 2002 8:29 am
	Quote > > The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable. > > On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio. > Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines. > Then. I have yet to find out why. They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too? Mike

Phredreeke Guest	Re: SG-1000 on GG Posted: Thu Jan 17, 2002 5:03 pm
Phredreeke Guest	My sister bought a game gear with a pirate cart for her daughter for christmas. It included both SMS, GG, SG1K and MSX games. Quote > > > The TMS9918 palette is totally messed up on an older Sega GG. Wrong colours, much too dark, to the extent that the games are barely playable. > > > On a newer GG (e.g. Majesco), there is no video at all when running SG-1000 games, only audio. > > Well. I do have several GG pirate cartridge with SG-1000 games, and they work fines. > > Then. I have yet to find out why. > They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too? > Mike

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Re: SG-1000 on GG Posted: Thu Jan 17, 2002 8:25 pm
	Quote > They have probably been hacked to use the correct palette. Aren't there GG pirate carts with MSX games too? Technically, I think that a cartridge that would rewire addresses and ports, and includes an MSX-1 BIOS, should be enough for playing MSX-1 games on SMS. I'll check how SG-1000 modes operates on GG.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Answer for Bart Posted: Thu Jan 17, 2002 8:38 pm
	Quote > Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?) I tested it now on the three kind of non-Megadrive VDP, and it works fine.

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Re: Answer for Bart Posted: Thu Jan 17, 2002 8:42 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote > > Does Bart vs. Space Mutants work on an SMS (with the 315-5124 VDP) with no graphics problems? (like bad tiles?) > I tested it now on the three kind of non-Megadrive VDP, and it works fine. Ok, this is good. Thanks for testing! Like the Y's name table bug, it could have been where the pattern generator base address register would possibly mask the upper bits of the VRAM address when fetching patterns, on the original SMS VDP. If the VDP is emulated like this, Bart vs. Space Mutants had bad tiles on the title screen. But apparently this isn't the case. In fact, the name table problem might be the only bug of this type with the SMS VDP. My Homepage

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Answer for TMS9918 on Game Gear (interesting find!) Posted: Thu Jan 17, 2002 9:20 pm
	Alright, I've toyed with the GG a bit tonight. TMS9918 modes seems to be fully supported on the GG, except for the palette which is taken from the usual SMS/GG palette. I've worked out a little bit of code that can be appended to a SG-1000 game, with minor modification to the SG-1000, and which setup a custom palette then run the game. And it works! Here is a pictures, running with a palette I made up which looks like the SG-1000 palette, but using SMS colors. I'll toy this palette a bit, and I think this way I would even be able to figure out the SG-1000 palette used on SMS, I guess it uses SMS colors. So, back to the pirate cartridges, the only thing they does is to set up a palette on startup (with the main selection menu), and that's it.

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Re: Answer for TMS9918 on Game Gear (interesting find!) Posted: Fri Jan 18, 2002 2:26 am
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote > So, back to the pirate cartridges, the only thing they does is to set up a palette on startup (with the main selection menu), and that's it. Do sprites still use the sprite palette? Meaning you'd set colors 0-F and 10-1F to the same TMS9918 palette values? If so, it might be interesting to make the background colors a little darker than the sprite ones, to enhance the visibility. ;) My Homepage

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Re: Answer for TMS9918 on Game Gear (interesting find!) Posted: Sun Jan 20, 2002 12:05 am
	Quote > Do sprites still use the sprite palette? Meaning you'd set colors 0-F and 10-1F to the same TMS9918 palette values? > If so, it might be interesting to make the background colors a little darker than the sprite ones, to enhance the visibility. ;) Good question. I tried - everything seems to uses colors 10-1F.

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