MiniMig + PowerPC = OS4 Hardware for all

[AJCopland]

This idea isn't impossible and has already been discussed in the original MiniMig thread but it is much harder to do than the MiniMig v1.x

There were lots of reasons but look at the efforts of people to make new PPC accelerators for the A1200/A4000 that have come to nothing.

Having put that minor downer on the idea I do think it will happen eventually but your idea of making MiniMig into an AGA capable machine is quite an endeavour in itself as it requires redesigning the MiniMig to use a differet cpu and 32bit data and address buses etc, as well as probably changing to a different type of ram... oh and that minor matter or rewriting the OCS chipset to be AGA capable.

Like I say, good idea, think it'll happen but its gonna take time. Dennis is an electrical engineer, most of us that are coming up with these ideas are from other fields of expertise! So its taking a little while to learn any of thise stuff.

@AndrewBell
Piru's opinions are his own, but you'd be better off listening to him since he knows more about the Amiga and developing software for it than almost anyone on these boards. His sometimes rather negative seeming attitude isn't really that, he'd probably love it if you turned around with the aforementioned PPC MiniMig design totally open sourced and with a working demo board, but he's quite familiar with how difficult these things are.

Its rather like someone whos just discovered a computer programming language like basic and writtent heir first hello world program turning around and saying: "right, so how do I make Doom3"

Andy

[AJCopland]

There's precedent for trying out other architectures too. We've always been able to run hardware emulators in amigas since the early days with PC286 support. Does anyone remember the Alpha 21164 CPU which the Siamese team were trying to build a machine around? :-D

First and foremost the MiniMig v1.x is an A500/A600 emulation machine. It doesn't have to stay that way and ideas like this are really great to see even if they are hard to do.

Andy

[AJCopland]

little wrote:
Nowadays MIPS is barely a memory and for quite some time sony has not used that architecture in anything new.

...except for the PSP which is MIPS32 based with matrix/vector co-processing hardware. Oh and the PS2. Mips is quite a nice architecture to work with actually. Not the best but nice and simple to get used to I found.

Andy

EDIT: darned typos...

[AJCopland]

The launch versions of Japanese and US PS3s, but not the European and UK, ones had something in there. It was either the MIPS cpu or the EE, not sure which. Either way somethings in there much like the IOP in the PS2 to provide hardware based backwards compatibility.

Unlike the IOP though you can't write code for it using the Sony APIs so it can't be used to offload anything. Shame really as the IOP was very handy for that kind of offloading work.

Andy

downix wrote:
The original PS3 had a MIPS chip in there as well IIRC.  Not as the main CPU, mind you, but in a peripheral fashion.

[AJCopland]

On-topic.
I thought there were still 603e and 604e based cores used in PowerPC cpus from Freescale. They might have been tweaked somewhat for process shrinks and cost reductions but they may well be fully compatible with all of the PowerUP and Warp stuff that exists.

If we're willing to settle for a lower end part at about 400Mhz or so then an MPC5200 would probably suit our needs.

The only problem with all of this seems to be the cost. All of the PPC board that i've seen being touted by people are really damned expensive because they use 10 layer board and incorporate everything including the kitchen sink!

So the real question is: Is it possible to do a basic PPC board with soldered on (DDR?) SD-RAM, the FGPA (500k gates+) and the MiniMigs current connectors for less than £200?

Or would it make more sense for us all to increase AmigaKits sales a little and order the Efika whilst turning the MiniMig into a PCI card for it?

Opinions on a postcard please :-D

Sorry for wandering a little off-topic everyone but:

little wrote:
BTW, The PSP is basically a scaled down version of the PS2, which was launched in 2000, in computer years that is a lifetime ago :-P

This is a myth that was caused by Sony stating that the performance of the PSP lay somewhere between a PSone and a PS2. The three of them are markedly different architectures and don't even use the same versions of the MIPS cpus.

They're all MIPS but different variants and with very different co-processors. I know this because I've worked on three multi-platform titles that all covered the PSP and PS2 ;-)

Andy

[AJCopland]

downix wrote:
Not realistically, no.

:lol: well its good to get that out of the way at least! How come though? I realise that the examples I'm thinking of are commercial ones like the LinkStation or some set-top boxes, I guess they have ecomony of scale on their side.

How about the boards for PPC then? Is it feasible for us to do homebrew boards with only two layers that support a PPC chip or are they going to require more as a minimum? I ask since it gets more expensive for people to make N-layer boards doesn't it and anymore than two is instantly outside the scope of etching our own.

[AJCopland]

AeroMan wrote:
Why use soldered DDRs ? Put a cheap PC memory slot

People have mentioned before that it makes EMI and timing of signal on the board harder to deal with. Don't know how much harder but I was thinking of the Keep It Simple Stupid motto :-D

Andy

[AJCopland]

If you can find the schematics which were in the original a500 manual you'll see that there's more than just data and address going through that connector but things like power, ground, clock (as in bus clock not the time) etc as well. Can't remember what else off the top of my head.

Not every pin of a 68k was mapped directly too the connector only the relevant parts basically.

[AJCopland]

Yeah you could find those or alternatively I could give you this link to the a500schema.zip I found earlier :-D

Which shows you a whole buncha schematics and the one called scanp9.jpg is the one you want. If you do some googling I think you should be able to find more info about them names used etc.

Andy