cd-based 2600

[liveinabin]

Right then, i'm REAL close to going ahead with this daft notion of building a CD based 2600, obv. I'd need a cuttle cart as a go between and the casing would have to be altered. Maybe I could go the woodgrain route and actually carve the casing out of wood and polish it up all nice My big question here is that since I live in the world of PAL, would it be worth me getting a Cuttle cart anyway?? as most of the available roms seem to be NTSC.

I also toyed with the idea of making a PAL/NTSC switchable 2600 (with composite output) but I don't know if that's possible.

[Ze_ro]

quote:

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Originally posted by liveinabin:

My big question here is that since I live in the world of PAL, would it be worth me getting a Cuttle cart anyway?? as most of the available roms seem to be NTSC.

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Dude, PAL/NTSC is up to the cartridge (or in this case, the rom), not the system. Or are you talking about a PAL/NTSC Cuttle Cart?

 

--Zero

[liveinabin]

Well, I'd imagine cuttlecarts will work the same the world over, what I really mean is - if all I can load into this thing are NTSC roms, won't a dedicated console that is working on a PAL system be a bit of a waste of time.

Surely I'd need PAL roms for my locale.

 

By the way, I've got a TV that'll do both tv standards - because I play NTSC ps1 games via a scart lead, I know an RF aerial connector (standard issue for PAL 2600's) will only transmit a PAL signal but what about composite? If I mod my PAL atari to composite will it play NTSC games in true colours?

[rasty]

I've got the CuttleCart on my PAL system and it runs great. A LOT of PAL games came up when I started looking for them, way more than I thought were available.

NTSC games will still play well on a PAL system with the CuttleCart, but with incorrect colors. Of course you'll need a TV that supports 60hz in order to play NTSC games. Most TV sets do, anyway..

 

I doubt a composite mod will get us correct NTSC colors since PAL 2600's have a different color palette (been told by Chad himself!)...

 

greets,

Rasty.-

[cschell]

quote:

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Originally posted by Ze_ro:

Dude, PAL/NTSC is up to the cartridge (or in this case, the rom), not the system.

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That's not quite right actually. It's a very widespread misconception though. PAL and NTSC differ in more than just their refresh rates, which is all that is controlled by the cartrige/ROM.

 

NTSC 2600 games draw frames at 60 Hz, which NTSC tvs can sync to, while PAL 2600 games draw frames at 50 Hz, which PAL tvs can sync to. The frame rate is controlled entirely by the software, or in other words the cartridge/ROM. This is why so many people say that the cartridge determines whether something is PAL or NTSC for the 2600.

 

However, the vertical sync frequency isn't the only difference between NTSC and PAL. They encode the color information in a completely different fashion. An NTSC 2600 encodes colors in NTSC format, and PAL 2600 encodes colors in PAL format. As it turns out, the PAL 2600 color encoding hardware has a different and, I believe, more limited palette than the NTSC 2600.

 

This leads to several artifacts. If you play a PAL game on an NTSC tv using an NTSC 2600, you will get the wrong colors because the palette is different. If you play a PAL or NTSC game on an NTSC tv using a PAL 2600, you will get black and white, because the PAL 2600 does not send color information in a way that an NTSC tv understands. (I believe it goes black and white, but I've never verified it personally.) All of this is in addition to the rolling screen problems caused by the difference in frame rate.

 

If you play an NTSC game on a PAL TV using a PAL 2600, you will get the wrong colors because of the different palette. So even though many PAL tvs can sync to a 60 Hz signal, the colors are still wrong. If you play an NTSC game on a PAL TV using an NTSC 2600, I don't know what you'd see, because I don't know how a PAL TV would react to an NTSC color signal. (Of course, many PAL TVs are multistandard, so they actually can decode NTSC signals correctly.)

 

There is also a slight difference in the clock frequencies PAL and NTSC 2600s run at, but it's very small and thus trivial.

 

As for how the Cuttle Cart works, its title and loading screens are 60Hz and use an NTSC color palette. However, I believe the color values are such that when mapped to the PAL palette they are still visible, but people who have used it in a PAL machine could tell you better. Once you load a ROM into the Cuttle Cart, it will behave like the ROM you chose, so PAL ROMs will be 50 Hz and use the PAL palette, NTSC ROMs will be 60 Hz and use the NTSC palette, and thus display differently than designed when used in a PAL 2600.

 

Chad

[liveinabin]

Thanks a lot C.Schell. i think prob. the best way to go about this (as this Atari is going to be CD only anyway) would be to import an NTSC 2600, composite mod it (so my PAL tv can convert the signal) and all should be well. Of course, this way I'll have access to a far greater library of games than I would with my PAL unit.

[liveinabin]

oh crap. just hit a MAJOR stumbling block, the file conversion software that comes with the cuttlecart is for PC, I have a mac........damn

[Ze_ro]

quote:

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Originally posted by C. Schell:

However, the vertical sync frequency isn't the only difference between NTSC and PAL. They encode the color information in a completely different fashion.

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Yes, well, the color problems are minor in my opinion. As long as the screen doesn't roll, I'd consider the game playable. It would be a bigger problem for a system with higher graphics capabilities (For example, playing Dead or Alive 2 and the characters having green skin would be a lot worse than Pac-Man being blue)

 

As far as I know though, most 2600 games have PAL versions out there... there are some exceptions to the rule though.

 

--Zero

[mos6507]

While the RF modulator differs in PAL vs. NTSC, there is only one TIA chip. Maybe it's clocked slightly slower on PAL, but the way the TIA itself generates colors is no different for NTSC, PAL, or SECAM. That's why the unfortunate result is that fewer colors are visible on PAL, and only 8 garish ones in SECAM.

 

If there had been a true PAL TIA, then you wouldn't lose colors like that.