fpga for ecs -> aga

[turrican3]

could it be possible to make an fpga for amiga 500 which give aga compatibility to it ?????
possible or not from technical pov ??

[Lord Aga]

Well, as a kind of a replacement mobo, yes.
Something like FPGA Arcade, but with an A500 keyboard connector, and a floppy connector. Possibly some break out cables for rear ports.
So you could close the case, and use a souped up AGA Amiga.
Technically, it is possible to build it today. We "just" need someone to take up such a project

But if you mean a board which would clip on to the A500 and give it AGA powers, well I don't know. Maybe. Maybe a couple of boards to place them around A500 board. Somehow my first scenario seems easier And it would improve on the old week spots.

[mfilos]

There was a prototype of an expansion board that had AGA chipset and also an adapter for A1200 accelerators like BPPC.
Would have been really nice for beefy A500 systems... on the other hand, for the price you should have gotten easily an A1200 in less money

[turrican3]

Originally Posted by mfilos

There was a prototype of an expansion board that had AGA chipset and also an adapter for A1200 accelerators like BPPC.
Would have been really nice for beefy A500 systems... on the other hand, for the price you should have gotten easily an A1200 in less money

what a crazy card... too bad it wasn't finished

[pandy71]

Originally Posted by turrican3

could it be possible to make an fpga for amiga 500 which give aga compatibility to it ?????
possible or not from technical pov ??

Yes, AGA itself was designed to work with 16 bit CPU i.e. MC68000 - Budgie/Bridgette i think have special mode to work with such configuration.
However in FPGA there is no sens to duplicate such configuration as there is plenty new possibilities to exploit.

[alexh]

Originally Posted by turrican3

could it be possible to make an fpga for amiga 500 which give aga compatibility to it ????? possible or not from technical pov ??

Replacing just the Denise chip is not possible from a technical POV.

[turrican3]

Originally Posted by alexh

Replacing just the Denise chip is not possible from a technical POV.

but it seems that phase 5 tried, perhaps they find a way to do this ???

[alexh]

I don't think they did. I think they connected their own recreation of an A1200 to the CPU socket of the A500 and removed all of the OCS/ECS motherboard chips.

If you want AGA in an A500 you should consider doing what a couple of people once did, put an A1200 motherboard in an A500 case.

http://eab.abime.net/hardware-mods/6...n-s-a1700.html

http://eab.abime.net/hardware-mods/3...e-s-a1700.html

[pandy71]

Originally Posted by turrican3

but it seems that phase 5 tried, perhaps they find a way to do this ???

Yes, this is possible - you need only recreate Alice and Lisa in FPGA i.e. provide board that use physical Agnus and Denise sockets (IMHO waste of time as you can fit whole AGA in FPGA and also MC68000 can be integrated at once, provide external memory and there is no need to struggle with A500 board).

[alexh]

Originally Posted by pandy71

Yes, this is possible - you need only recreate Alice and Lisa in FPGA i.e. provide board that use physical Agnus and Denise sockets

Are you sure that all the I/O you will need will be on those two sockets?

[pandy71]

Originally Posted by alexh

Are you sure that all the I/O you will need will be on those two sockets?

Yes - 99.99% sure (100% only when such HW implementation will be made) . Agnus is main system controller - replaced by Alice in AGA, Denise as video converter replaced by Lisa - remain part is quite simple (under some limitations even VIDIOT can be leaved untouched - not sure what is VIDIOT speed but with dithering/oversampling/noiseshaping should be possible to create 24 bit on 12 bit converter).

Personally i see no justification to do such strange thing like AGA on OCS board. FPGA probably will be large enough to integrate also Paula and both CIA's - integration of the CPU is open, external SDRAM and that's all.

[Leffmann]

AGA requires chipmem to have 4x as much bandwidth, can that really be solved by just replacing these two chips?

[Lord Aga]

Well, as I said earlier, it's so much fuss that a FPGA replacement mobo is much easier to do

[turrican3]

Originally Posted by Lord Aga

Well, as I said earlier, it's so much fuss that a FPGA replacement mobo is much easier to do

for sure a powerfull fpga which could replace our old a500 faulty or dead...
Good idea.

[alexh]

Shame the Keyrah v2 doesn't support the A500 keyboard

[Jope]

It does, but the flexi cable is a bit short. :-)

[robinsonb5]

Originally Posted by Leffmann

AGA requires chipmem to have 4x as much bandwidth, can that really be solved by just replacing these two chips?

As long as the FPGA-board provides its own replacement Chip RAM, then in theory, yes.

[pandy71]

Originally Posted by Leffmann

AGA requires chipmem to have 4x as much bandwidth, can that really be solved by just replacing these two chips?

Most of the DRAM chips (AFAIR 41256 also) support fast page mode - but this is not the case - RAM should be local (FPGA), probably SDRAM thus with much higher bandwidth and with few tricks it can be designed and offer higher (much higher) bandwidth (hide all DMA cycles form CPU for example thus no penalty even for most demanding video mode)