A2630 accelerator - 040 upgrade possible?

[commodorejohn]

The title pretty much says it all. I rescued a 68LC040 (ceramic PGA version) from a junker Mac at the recycle center yesterday, and I'm wondering if there's a simple adapter to use it in place of the 030 (also a PGA, but fewer pins) on my A2630 accelerator board. Does anybody have any information on this?

[mongo]

Can't be done.

[commodorejohn]

Why not?

[yssing]

I can be done, but its not simple...

http://www.gb97816.homepage.t-online.de/gba_tk.htm

[cha05e90]

Why not?

The answer is no. Electric, pin-out and some more things incompatible. There is nothing like an "adapter" except a complete - not yet known or build - sub-board, where the 2630 would only feature as a mechanical base. In the end you might as well make a complete new 040 accelerator board. Search ebay. ;-)

EDIT: Yes, you're right, the GBA featured this kind of "adaption" - but in the end it's more or less a complete own accelerator...

[commodorejohn]

Okay, thanks. Guess I'd be better off seeing if I can get an 040 accelerator cheaper without the processor...

[ElPolloDiabl]

One of the best reasons to have an 040 is the massively fast math. Your LC model lacks the math unit. Keep searching and get a full 040 it will be worth it. Only downside is they run hotter than the LC version.
If you've got a 2630 fit it out to the max and stick with it. Although the 040 will double the speed it will cause bugs in a lot of programs (mostly games) the 030 doesn't.

[commodorejohn]

Yeah, I know the LC doesn't have the FPU, but it would've been nice to be able to put it to use - no sense saving it from the scrapyard just to have it sit around taking up space. (And even without the FPU, I'm guessing the massive cache increase and longer pipeline make a pretty noticeable difference!) Maybe I'll hang onto it for when I finally get around to a homebrew computer project like I've been wanting to do...

[countzero]

presence (or lack of) the FPU wont create any noticable difference except for the apps that specifically use it (3D stuff, some spreadsheets, and database apps). workbench doesnt use the FPU at all AFAIK.

[ElPolloDiabl]

presence (or lack of) the FPU wont create any noticable difference except for the apps that specifically use it (3D stuff, some spreadsheets, and database apps). workbench doesnt use the FPU at all AFAIK.

Any video decoding or audio decoding programs (like mpeg mp3) use the FPU.

[countzero]

do they ?

http://forum.doom9.org/showthread.php?t=75095

[SpeedGeek]

I investigated this matter 7 years ago and concluded the complex logic required to make a 68040 to 68030 bus protocol adapter would be impractical (but not impossible). So I proceeded to modify the A2630 to run at clock speeds up to 52 Mhz. The archive is not complete but it's enough to give you a good idea of the amount of work involved. The last changes I documented should be available under http://www.amibay.com/showthread.php?t=13965

[commodorejohn]

Well, I'm not desperately in need of it at the moment, but I'll keep that in mind. Thanks!