Maybe a dump question about PAL/NTSC

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lunatic
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Maybe a dump question about PAL/NTSC

Post by lunatic » Sun Jul 28, 2013 2:12 am

But would it be possible to switch the AD725 with this chip?
http://no.farnell.com/rohm/bh7236af-e2/ ... dp/1716147

And then be able to choose PAL or NTSC?

Maybe there would have to be code changes in the kernel to support PAL too? Because of different amount of scan lines? or?

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Re: Maybe a dump question about PAL/NTSC

Post by CunningFellow » Sun Jul 28, 2013 2:40 am

Little bit more too it than just adjusting the video timing I would think.

The 28mhz clock for the Uze was chosen becuase it is 8x the 3.57mhz NTSC colour carrier.

With the colour carrier on PAL being 4.43 Mhz then 8x that is 35Mhz and probably well out of the range of an 644 with a P at the end of the chip number.

You could possibly do PAL 60 without much more effort, but any TV made in the last decade can decode PAL or NTSC with out issue so I can see little point in the exersize.

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Re: Maybe a dump question about PAL/NTSC

Post by uze6666 » Sun Jul 28, 2013 4:12 am

Never heard about this chip and it's spec sheet is too sparse to know if it would work with the Uzebox kernel. In any case PAL timing is too different (not the same amount of scanlines, etc). The kernel could be modified, but all the existing games would not work well. PAL comes up now and then on the forums, but in the end, as CunningFellow said, all PAL TVs sold in the past decade will handle NTSC just fine.

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Re: Maybe a dump question about PAL/NTSC

Post by lunatic » Sun Jul 28, 2013 8:36 am

Hi,

Yes, i guess most tv's do both NTSC and PAL these days.
What about using it as a replacement for NTSC conversion? It costs less than half of the chip you use.

:)

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Re: Maybe a dump question about PAL/NTSC

Post by uze6666 » Sun Jul 28, 2013 3:33 pm

I guess it could, however it can not be ordered from North America apparently. Perhaps because it reached end-of-life, Mouser mentions "Not recommended for new designs".

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