Why no FPGA accelerator cards?

[SamuraiCrow]

http://www.a1k.org/forum/showthread.php?t=20223&highlight=tg68

Yep that is an A500 running with the 68k-core in the FPGA-board.

So sure it's possible, wether it's (commercially) viable is another question.

It's hard to imagine why anyone would want to keep using old 3.5 MHz graphics chips when SuperAGA is slated to run quite a bit faster.  The basic idea is that replacing the entire motherboard with an FPGA-based board would be more practical and cost effective than replacing only the CPU.

It will take some time before we get to that stage but things are looking toward the full motherboard replacement avenue and will be the most practical at least for the NatAmi MX board.

[SamuraiCrow]

Well if you can't do an 060 FPGA core for less than an actual 060 chip on an accelerator card then don't. The guy asked a simple question.

As to 3.5mhz chipset<----?? The bus is 7mhz, so is the chipset (well actually the whole thing is run at 28mhz I believe and clocked down to 7.09 or 7.14mhz IIRC)

That reference was referring to the A500 assuming it has all Chip RAM and no Fast RAM in its defualt configuration.  The A500 did not have 70 nanosecond memory capable of 14 MHz bus access and therefore the CPU and chipset had to split the 7 MHz bus speed between themselves taking every other clock cycle for each.

[SamuraiCrow]

I'm sorry but you are talking bollocks. In every Amiga chipset (OCS/ECS/AGA) the Chip RAM memory bus is run at ~3.5 MHz. The CPU can access every other memory cycle at most while the chipset DMA can access all of them (and can block the CPU for long periods).

Wow!  That's even slower than I realized!