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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: 1NOM155 on August 07, 2007, 03:12:44 PM

Title: Amiga 1200
Post by: 1NOM155 on August 07, 2007, 03:12:44 PM

can any one explain this?

the Amiga 1200 boards have a socket never been use, the same size of the 68882 FPU, the Commodore don't used the FFU in the future, if they don't use the CPU 680EC20, and use the 68020???

Title: Re: Amiga 1200
Post by: 1NOM155 on August 07, 2007, 03:15:17 PM

MC 68882 FFU:

(http://amigakit.leamancomputing.com/catalog/images/MC68882.jpg)

A1200 Motherboard:

(http://www.old-computers.com/museum/photos/Commodore_Amiga1200_MotherBoard_1.jpg)

Title: Re: Amiga 1200
Post by: Piru on August 07, 2007, 03:33:03 PM

Quote

the Amiga 1200 boards have a socket never been use, the same size of the 68882 FPU, the Commodore don't used the FFU in the future, if they don't use the CPU 680EC20, and use the 68020?

Could you rephrase that?

Title: Re: Amiga 1200
Post by: Oli_hd on August 07, 2007, 04:07:08 PM

Quote

if they don't use the CPU 680EC20, and use the 68020???

The 020 isnt like the 040 and 060 chips, the "standard" 020 doesnt have an FPU or MMU, the FPU is always external (same as the 030).
The difference between an 020 and an EC020 is the EC chip only has a 24bit address bus.

So basically the FPU will always be external on an 020 and if Commodore wanted they could have just stuck an FPU on to those pads... they just didnt.

Title: Re: Amiga 1200
Post by: golem on August 07, 2007, 05:28:11 PM

So could some person who is a wizard at soldering do just that? Add a 68882 to their A1200 without any other changes?

Title: Re: Amiga 1200
Post by: rkauer on August 07, 2007, 07:28:06 PM

Quote

golem wrote:
So could some person who is a wizard at soldering do just that? Add a 68882 to their A1200 without any other changes?

 Yeah, right. And how do you will discover the values of the other periferal components around?

 Maybe you can try an "ouija table" with Jay Miner to discover these values.

Title: Re: Amiga 1200
Post by: Doobrey on August 07, 2007, 07:34:47 PM

And if the seance with Jay fails, you could always look them up in the A1200 schematics (http://www.ianstedman.co.uk/Amiga/schematics/schematics.html) :-)


Edit:
 Just checked, it looks like it only needs some caps for decoupling etc (C0A,C0B,C0C,C0D), and they're already present on my Rev 2B board.

Title: Re: Amiga 1200
Post by: TjLaZer on August 07, 2007, 07:43:58 PM

Not worth the trouble, just get an upgraded Turbo card and be done with it!

Title: Re: Amiga 1200
Post by: Lemmink on August 07, 2007, 09:13:57 PM

Just adding an FPU without fast RAM isn't worth much. On the other hand any fast RAM expansion comes with an own FPU socket.

Title: Re: Amiga 1200
Post by: 1NOM155 on August 09, 2007, 10:51:59 AM

i wanted to know if it was possible, nothing more :P
since board has space of socket.

Fast Ram??? the Amiga 1200 have upgrades.....

Title: Re: Amiga 1200
Post by: derringer3 on August 09, 2007, 12:29:52 PM

If you want to solder a 68882 FPU to your MB, simply you can. It will working. (of course if you have some knowledge how to do it.) But as mentioned above, it hasn't got much benefit without extra ram. (which if we speaking about the 1200, is Fast ram.)This is true for the default 68020 in your amiga. If it has some, it will do its job more faster.

Maybe Some 3d games, but mostly apps like Imagine/lightwave can use the fpu.

 

Title: Re: Amiga 1200
Post by: 1NOM155 on August 09, 2007, 02:12:01 PM

my english, wasn't correct, i wont say, he can use the trapdoor to expand the memory.

but the CPU of the a1200 is a MC68EC20, and not MC68020. so we don't have much advantage using a FPU with MC68E20, right?

better buy an accelerators, and don't make the modification.