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Introducing: AntiX, the ANTIC Switch !

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1 hour ago, chevymad said:

Using a sophia2, won't that cure the 50hz output issue? Plus sophia will automatically switch between pal/ntsc. 

Solves half the issue.  We still need PAL/NTSC ANTIC.

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18 hours ago, rmzalbar said:

There is a similar project for the C64 called VicII², and indeed, it has every single one of the problems you are listing here. To get around all of the issues, they had to go with relays instead of solid state logic (in part so the power is switched) and a side-by-side board as opposed to a stack; and even with the side-by-side layout, the need for heatsinks on the ICs means that it will only fit in the taller breadbin-style models that have enough space under the keyboard. Perifractic has a great video on how they developed it and dealt with each of the challenges that is worth a look as there are a lot of parallels there.


The end result was a brute-force approach that turned out to be physically imposing and pretty expensive. And, of course, for North Americans we need a monitor capable of full PAL decoding, not just 50hz capable as the case would be with the Antix. I have one in just one of my breadbins and I really like having the convenience of it, but it was a little finicky to get going. Crucially, the Vic-II also handles direct RF generation, so switching and tuning the clock generator and switching the RF output also had to be done which isn't really the case with the Antic since some of those functions are on GTIA.


Given the expense and limitations, I could see where an FPGA Antic implementation could be the right drop-in solution in this case.

That's interesting. I actually had a look at using the same idea as AntiX on the C64 and thought it would actually be easier than on the A8. Interesting to read that it didn't turn out to be like that. 

I believe something like has now been done with POKEY but then with NTSC and PAL ANTICs would be more convenient and safe.

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I was mistaken when I said the Vic-II handles RF generation. That's not true of course, it generates Luma and Chroma.

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