Why no FPGA accelerator cards?

[A1260]

Why would someone spend a bucket load of time and money on r&d for such a small, if any, return? Doesn't make much business sense...

you talk about old amiga here, there are actually nearly no money in it, but there is a demand and of interest for some to make the old amiga a bit better. and there you find your answer why people like jens make these things he makes, it may not make you rich but the challange and thinkering is also the fun part of it.

[commodorejohn]

I would guess because an FPGA-based accelerator offers essentially no advantage over one using an actual 680x0 chip and requires much more time and effort to design (look at how much effort has gone into NatAmi's CPU core.) If you're designing an FPGA-based system anyway, sure, it makes sense, but if you're just trying to get an accelerator for an existing Amiga system, it's a lot simpler, cheaper, and less time-consuming to just use an actual chip.

[DCAmiga]

Hmm In regards to the topic isnt Individual computers producing them for the Amiga 600 & 1200 .. ie ACA 630 & ACA 1230 ? (Sold by amigakit)
But I wonder if it would be possible for a V5 Coldfire CPU (300mhz+) on a FPGA Accelerator card, since the V5 Coldfire is binary compatable with amiga
Would hate to think of the price tag though ... lol

[tone007]

Hmm In regards to the topic isnt Individual computers producing them for the Amiga 600 & 1200 .. ie ACA 630 & ACA 1230 ? (Sold by amigakit)

Those are using real 68030s.

[billt]

The problem is the content. There is no 32-bit 68k CPU core, FPU or MMU (yet) to program into it.

Add to that the price of the FPGA (at least 2x as expensive as real 68060 for something that might be able to match performance).

Only a matter of time. Besides, if someone were to design such a board, would the core not be a part of that design?

I think it's a neat idea. Perhaps moreso for bigboxes than keyboardboxes because as others have said, I'd want all sorts of modern ports, audio and graphics on the thing as well. But I wouldn't stop there, as an FPGA would make a fantastic bridge to a true CPU accelerator, such as to some industry standard PowerPC module, as a secondary mode. It could do either job. I wouldn't have it do both at the same time though.

[DCAmiga]

Those are using real 68030s.

Ohhh yeah my mistake sorry, When I think Individual Computers I think of Jens Schönfeld and FPGA for some reason ... :hammer:

[orb85750]

I would guess because an FPGA-based accelerator offers essentially no advantage over one using an actual 680x0 chip and requires much more time and effort to design (look at how much effort has gone into NatAmi's CPU core.) If you're designing an FPGA-based system anyway, sure, it makes sense, but if you're just trying to get an accelerator for an existing Amiga system, it's a lot simpler, cheaper, and less time-consuming to just use an actual chip.

True, but FPGA is not as limited in terms of potential performance.  It wouldn't necessarily be "just an accelerator," it could be the "mother of all 68K accelerators."  Could sell better than PPC accelerators IMO.  Imagine an incredible power-boost for your classic Amiga that is still largely compatible with old software.

[NorthWay]

If anyone ever thinks of doing another 4000 cpu card then look into the possibility of putting 2M on the card itself and make a connector to the chipram sockets.

The custom chip timing is of course set in stone, but with SRAM you could get a lot more cpu cycles once you stop crossing the custom chips to get to chipram. (Yeah, it would take some extra logic to time and route the cpu signals internally on the card. Don't know if there would be too much noise to connect to the SIMM sockets though...)

[billt]

As for new graphics modes, etc, that's another issue entirely. Maybe a standard P96 style graphics card could be implemented in the FPGA.

http://wiki.opengraphics.org/tiki-index.php

Though this alone takes a rather large and thus expensive FPGA as I understand. That's large reason why their prototyping boards are so expensive.

[billt]

it may not make you rich but the challange and thinkering is also the fun part of it.

+1

And Jens must do well enough to continue his business.

[commodorejohn]

True, but FPGA is not as limited in terms of potential performance.  It wouldn't necessarily be "just an accelerator," it could be the "mother of all 68K accelerators."  Could sell better than PPC accelerators IMO.  Imagine an incredible power-boost for your classic Amiga that is still largely compatible with old software.

I suppose so; if the estimates on NatAmi's CPU core hold up in actual use, you could get it a good bit faster than any of the actual 68k chips (ColdFire excepted.) Still, at that point you're harnessing a 150MHz CPU to a bus and chipset that still run at 3.5MHz; it's kind of impressive, but in terms of performance boost it's like those early Pentium machines that hooked a 90MHz+ CPU to ISA-bus peripherals. You'd be better off just doing what NatAmi's doing and creating a compatible, expanded reimplementation that runs the whole system at a consistently high speed.

[psxphill]

Still, at that point you're harnessing a 150MHz CPU to a bus and chipset that still run at 3.5MHz;

You'd put ram on the CPU bus, so you wouldn't need to touch the motherboard until you access the customer chip registers. With write queuing then it wouldn't impact performance much. Reads are more of a problem unless you can execute instructions out of order.
 
The bus on AGA amigas runs faster than that as well.
 
Even modern PC's have multiple buses running at different speeds.

[billt]

The problem is the content. There is no 32-bit 68k CPU core, FPU or MMU (yet) to program into it.

http://www.amiga.org/forums/showpost.php?p=546480&postcount=222

[commodorejohn]

You'd put ram on the CPU bus, so you wouldn't need to touch the motherboard until you access the customer chip registers. With write queuing then it wouldn't impact performance much. Reads are more of a problem unless you can execute instructions out of order.
 
The bus on AGA amigas runs faster than that as well.

Yes, but still. Raw CPU horsepower plus fast RAM is all well and good, but you're still going to have that bottleneck. It's not just the chip registers, either. Not only does the chipset rely on chip RAM (which can't be accelerated,) any Zorro cards are running at a mere 2x the chipset speed. It's still better than an unaccelerated Amiga, it's just not as good a solution as a uniformly faster system.

[Belial6]

It seems to me that the comment about the wedge case being more valuable than the hardware inside holds some truth.  Since that is the case, it would make more sense to make an FPGA based motherboard replacement.

I know, not enough market.  BUT since the FPGA based systems are so much smaller, the answer isn't to make a custom Amiga format board.  The solution is to make an adapter.  That is what I did with the MiniMig case I am finishing up now.  I picked out my case, which happened to be an external USB DVD/Harddrive case.  I installed all of my ports in the case with cables to the actual ports on the MiniMig.  The only barer to putting an existing MiniMig in an Amiga wedge case is the placement of the SD card, which I was advised not to try and cable out, and the fact that the mouse and keyboard are PS2.

While they would take SOME effort, the mouse and keyboard should not be too much of a technical feat to get past.

Using this I don't see any reason that the MiniMig, or ReplayArcade could not be put in an original Amiga case.

[glitch]

Hey, now THAT's a great idea.  MiniMigAGA form factor re-worked for existing models!  Me likey!

All of the extra real estate could be used for additional RAM slots, etc.  Mmmm...