Wishing for mainboard with new component layout for A1200

[alexh]

And if it could end world hunger and all wars that would be good too :-)

George's project was made possible because most (all?) the chips on the A1000 motherboard were socketed. On the A1200 they are all surface mount. Harvesting the chips for a new A1200 motherboard would be prohibitively difficult.

I have a feeling that George was also a PCB designer by trade and was able to "borrow" on a lifetime of experience and access to the latest PCB tools which greatly reduced the NRE of the PCB.

One of MiniMig's great strengths (only strength?) is its form-factor. Being so small compared to any real Amiga was a great selling point. Had it been the same form factor as an A500 I doubt it would have sold in as many numbers.

I don't believe their is a willingness to develop a replacement A1200 motherboard (at the moment). This may well change if an open source AGA implementation becomes available.

Although... I was just thinking... I wonder why Jen's schoenfeld did not consider making his new A1200 scandoubler into an ultra basic RTG capable video card?? The FPGA and the RAM would almost certainly have facilitated one.

Maybe there were not enough CPU signals going to the Lisa chip to which it clips.

[alexh]

trekiej wrote:
Does the Amiga 1200 and the 600 have the same layout on the back except for the mouse ports?

Yes

[alexh]

A6000 wrote:
There seems to be no shortage of people willing and able to design new boards, we have 4 already

Four?

A6000 wrote:
so why not an a1200 replacement?

Because of the availablity of the AGA chips. Or rather lack of it.

A6000 wrote:
we certainly would not reuse 15+ year old components, a new design would use new modern components.

You HAVE to use some old components. You cannot get anything to replace the Commodore AGA custom chips.

Unless you design new ones (ala MiniMig / NatAmi). Which isn't going to be easy, quick or cheap (not to mention compatible). Also, MiniMig is not AGA (or finished) and NatAmi is a closed source project :-(

[alexh]

A6000 wrote:
SUPERAGA.

Doesn't exist.

[alexh]

arnljot wrote:
MiniMig:
As I understand part of it is based on the UAE code.

Wrong. Denis said that he used the Commodore HRM (Hardware reference manual) to create MiniMig.

arnljot wrote:
Now I seem to have read that the FPGA doesn't have enough umph or gates to do AGA.

Partly right. It's not so much not having enough capacity. More that it doesn't have a 68020 CPU or enough RAM.

arnljot wrote:
if the MiniMig get's enough time to mature, it'll have USB

I hope not. Native USB and Amiga are not a good combination.

arnljot wrote:
"SUPERAGA". Now alexh says that it doesn't exists. Well, it's perhaps a bit harsh.

Why? It doesn't exist. You cannot buy it anywhere. The source code is not available. For all intents and purposes it doesn't exist.

arnljot wrote:
If we agree that Natami exists

But we don't, because it doesn't. (Yet)

arnljot wrote:
then it follows that the new AGA chipset exists, because Natami doesn't use any of the Amiga's original custom chips.

But even if Natami did exist and was for sale it today, it would come with it's own PCB!

If you are asking if NatAmi could be made to fit into an A1200 case, that is practical and possible sometime in the future, if NatAmi is released and the designers are willing. It's certainly not something you can start planning today.

arnljot wrote:
What people hold against Natami is it's ambitions and that there has only been one demo.

And I don't think it was a demo of AGA? It was the "Super" extensions which the author appears to have created for a previous (paid) project.

I wish the creator of NatAmi all the luck in the world. It is obvious he is an Amiga enthusiast who is also a knowledgeable software/hardware engineer who, having done a 3D accelerator project thought... wouldn't it be cool if the Amiga had these features and set out to create an Amiga compatible chipset with extensions.

But at the moment the website contains aspirations which are embarrassingly touching on fantasy. The technical details are too low, they contradict themselves and seem to negate compatibility with classic Amiga. I am almost sure a lot of the website is not the work / words of the developer but the people who are surrounding / helping him with the website.

But if he's a real hobby developer, he wont give a crap what other people think. He's doing this for himself, for fun, screw what anyone else says or does! He's doing the bits that are fun, skipping the bits which are boring. I think it's cool.

[alexh]

arnljot wrote:
as a user I must disagree on this one. Just a mouse and keyboard alone almost justifies this one to me

But they dont work!!

Workbench yes... Games No. (Well mainly no)

You see the games hit the hardware registers of the custom chips. They do not go via the OS and so (AFAIK) do not work with USB keyboard and mice.

Most USB mice and keyboards support legacy PS/2 over USB so with an adapter you can use them directly with MiniMig via the PS/2 ports which are wired to the hardware of the custom chips.

arnljot wrote:
and then add mass storage and it´s perfectly clear to me that this is a very important feature.

You get mass storage via IDE, replicate the GAYLE registers and you have a 100% compatible interface AND drivers.

arnljot wrote:
slightly off topic:
It seems that the 68040 are abundant, in speeds 25mhz, 33mhz and 40mhz. Would it be a suitable choice for a "power minimig"? Which one of the 68 series is most common, except for the 68000?

It has to be 3.3v I/O to interface to the FPGA. This limits which 68k you can use. You cannot use any 040 from the Amiga days. Not without extra electronics to convert the I/O levels. You cannot even use a regular 68000 out of an A500! (MiniMig uses a special 3.3v I/O 68000)

As I have said before the 68060 is NOT 3.3v I/O (unless the specs at Freescale are wrong). It is 3.3v core, 5v I/O.

[alexh]

I'm unsure... some of the Freescale documentation says 5v I/O in some places and 3.3v I/O in other places.

I'm wondering if it does both?

[alexh]

arnljot wrote:
But how cool would it not be to be able to boot of a memstick which you also use at work with WinUAE? Hmm...

I already do it now using A4000 and a CF card (which is IDE).

[alexh]

Not if it is just digital. You should look up TTL thresholds. 3.3v is still a HIGH.

[alexh]

bloodline wrote:
So the the 060 could happily run at 3.3v and simply tolerate 5v inputs...

Maybe, I think it is more complicated than that. It probably requires voltages on certain pins at certain times...

[alexh]

Eh?? That is just a remake of a standard voltage regulator board for an Apollo card. An ultra simple board which has been on sale for years, that PG has been selling to people on this board for years.

All the "good bits" (if there are any) are actually in the 1240/1260 board design itself, not this addon.

The MiniMig PCB would require a full re-design to use an 060 CPU. MiniMig is a two layer PCB which would almost certainly not be possible for an 060 design due to the number of power and ground pins there are compared to a 68000

Not to mention that MiniMig is a 16-bit design and the 68000 is a 32-bit processor, there are not enough pins on the FPGA that MiniMig uses for a 32-bit processor so you'd have to change to a different FPGA too.

And 1.5Mbytes of RAM is not enough ;-)

[alexh]

arnljot wrote:
@alexh
are you saying that BLizzard, Cyberstorm and Apollo 060 cards are much more (4++)?

Yes.

arnljot wrote:
What would these "good bits" of such a card be?

The power & ground routing mainly, handling all the extra pins, perhaps some electronics to support dual voltages.

[alexh]

arnljot wrote:
alexh: Is it true that a challenge with with the current design is that they must reimplement a memory controller for newer more common memory?

Yes, but it has already been implemented by Tobiflex for the DE1 / DE2 boards.

arnljot wrote:
alexh: Are there FPGAs around that can handle a 68020 if Tobiflex's FPGA 68000 gets reimplemented as a 020?

Sure, but how much do you want to pay? And I dont see an 020 coming out any time soon. The 68000 isn't perfected yet.

arnljot wrote:
4) Mass storage needs to be implemented. IDE is on the wishlist for many people.

For MiniMig, you wouldnt want true IDE. Just re-route access to the MMC card.

arnljot wrote:
This could end up then with an AGA A1200-like machine with either an expensive 060 or an FPGA implemented 020. PS2 ports for mouse and keyboard.

Where did you get your AGA core from??

arnljot wrote:
alexh: If this is done, do you think that the board would need two FPGAs?

Depends on economics. Probably one big one.

arnljot wrote:
If so, what would that do to the cost of the board?

Too many unknowns to even speculate.

arnljot wrote:
If we would wait for the semiconductor industry, is it likely that we in the next year would get a cheap FPGA that hold AGA+020?

Of course. But what is this "waiting" you talk about? It's not like you have anything to put into an FPGA if you had one in front of you.

arnljot wrote:
Many questions, but I'm trying to get a picture of this so that my expectations to who ever is working on the MiniMig is reasonable

AFAIK there is no-one really working on MiniMig, there are about 3-4 people who play with it in their spare time, as a hobby, nothing more.