FPGAARCADE minimig compatible board, comments?

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Here's an Amiga graphics roadmap:
1985 OCS  (A1000, A2000, A500)
19~~ Ranger
1990 ECS  (A3000, A500+, A600, A2000)
1992 AGA  (A1200, A4000, CD32)
1993 AAA  -  
1993 Hombre -

It should be possible to implement them all given enough hackertime

So you could select to have an A500 with AAA and SID sound.. or whatever mutation gone wrong test you want that day :-D

Ofcourse there's also the options of Picasso, or some selfdesigne graphics subsystem.

Edit: ECS/A2000

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Ie you can't use an ordinary buck converter for DDR VTT ?

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What are the special VTT requirements?

As a sidenote, buck regulated power won't do for A/D either?

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Reminds me of the nasty situation where pull-up to higher voltage supply may cause lower supply rails to have higher than designed for level.
I recall Xilinx had some app-note on how to solve it. But one might be a resistor and zener in series that just burns it away (hopefully ).

(I think it's related to the exploit that uses the builtin protection diodes to attach a 3,3V pullup to get an 3,3V-TTL compatible i/o)

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AJCopland, Ans she feels.. "hmm.. better find another boyfriend" .. ?  :-D

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mikej, There are some ways to get that -5V:

(AB)use an MAX232 style capacitor chargepump to invert. Dunno how noisy it's output is.
You could use an Cuk converter or an Buck-Boost converter. And then a linear regulator following that for that low noise supply.

Another approach which I'm not sure will work is to put a small DC-blocking capacitor in series with the audio signal. And then arrange two (pos+neg) linear regulators to divide the +5V into +2,5V and -2,5V. Line-level audio signals are +/- 1V so it should be possible once you have the proper supply voltages.

In worst case.. just try

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What is the reasoning behind adding another output buffer..?
If the switched cap need extensive filtering, go with an proper switched regulator and get the full juice.
Then use a heavy inductor and capacitor to filter. Don't forget radiated noise (shielding).

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Go with S/P-dif and get rid of the problem altogether ..

Don't forget that HDMI supports transmitting Audio on the same cable as Video.

Another option is to offer audio digital stream directly to an external connector and let and an additional circuit pcb handle it in any way the user see fit.

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As you already have the DVI connector everything needed for HDMI is present. Only an mechanical adapter is needed.

I haven't researched, but I think the restriction is to use the name "hdmi" in marketing. Or mentioning it in documentation.
I think you could say "DVI with sound".

So time for that secret "dvi sound patch"

As for analog solution, I think the most viable ones has been outlined by now. Personally an op-amp that manages with plain +V rail seems neat.

Have you tested if the output works for line-in on an standard amplifier?

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The "filter" we are talking here is it to do the same task as the A500 filter that was directly connected to the power LED on the A500 ?

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matthey mentioned "Superscaler would be super difficult to implement". Softcores is the thing, but they might be a pain to program

However I suspect 68020 can do everything 68030-68060 can, albeit slower.. So it's a good starting point, speed can initially be achieved the Intel way.. more MHz & cache :-D

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I agree. New processor instructions would be highly unsupported. But my thought were more like "if that feature had be implemented then we could.."

New video modes would benefit workbench. But no demo/games I suspect.

Btw.. AMD Am7900 Ethernet interface seems to be quite widespread and QEMU has source code to clone it.