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FPU/PMMU for LC

Gil

Well-known member
I was going to post this in the Trading post, but I thought I'd ask a few questions here first.

I am looking to upgrade my LC with a 68881 FPU as well as the 68851 PMMU so that I can run some kind of Linux on like (NetBSD, OpenBSD, or the like). First off, I'm wondering if this is even possible, as I see no slots on the motherboard that would allow these chips. I've seen Ethernet cards that allow the FPU (but not the PMMU), but I'm not sure how they would work with Linux.

And lastly, I can't seem to find any place online that sells these (only eBay, and right now they are pretty expensive)

Looking for advice. :)

 

porter

Well-known member
Not going to happen, the LC was not designed to add a PMMU. The original II was the only one that would.

The options are....

a. get an LCII with a network card and an FPU slot;

b. get an LCIII which already has the FPU slot on the motherboard; and

c. best of all, get a Quadra 605/LC475 and swap the 68040LC for a full 68040.

 

Gil

Well-known member
Darn. Well, since I have an unused LC III, I suppose I'll use that. Still have to figure out where to get a 68882 without spending a fortune. :-/

 

Temetka

Well-known member
I *might* have a full 68040 CPU you could slap in there if you want I can check my CPU stack.

 

joshc

Well-known member
A 68882 won't do a whole lot of good, and finding a 25MHz one that fits your LC III will be more expensive than its worth. I would recommend a Quadra 605 instead.

 

IIsi

Well-known member
hehehe, I have a MC68851 in my desk drawer. With the golden cap removed. :) I also might have a PLCC 68882, but i don't know the speed. There is a 20 Mhz one currently in my IIsi, I might have another like it. I'll check.

 

Scott Baret

Well-known member
I may be wrong, but wasn't there a card for the LC's PDS slot with a 68881/68882 on it? For some reason I seem to remember hearing about them, although this could have been back from when the LC came out and people were speculating on what was going to be available for the slot besides Apple's IIe card.

 

IIsi

Well-known member
I may be wrong, but wasn't there a card for the LC's PDS slot with a 68881/68882 on it? For some reason I seem to remember hearing about them, although this could have been back from when the LC came out and people were speculating on what was going to be available for the slot besides Apple's IIe card.
Yes, many Ethernet cards included this socket (though not including the chip).

 

LCGuy

LC Doctor/Hot Rodder
I also seem to recall Daystar or someone else coming out with a card that only had an FPU slot (with an FPU installed), didn't they?

 
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