Fujitsu 30387?

[gshv]

Yesterday I received Cyrix 486SXL processor, which was soldered on Makeit 486 upgrade board. I already had two other Makeit 486 upgrades with TI486 chips before, so that's the third one in my collection:



The reason I had two of them is because one upgrade came with Cyrix 387 coprocessor (on the left), and another didn't have it (in the middle). Now, the third upgrade has a chip under the socket, where 387 co-prococessor is supposed to be, and that chip is made by Fujitsu:



The Fujitsu chip is approximately the same as as Cyrix 387, it has about the same number of leads as Cyrix 387, but it's slightly thinner. Markings on this chip are:



To me it does look like 80387 co-processor. I never heard about Fujitsu 80387 co-processors, and quick search on Google brought nothing useful. Has anybody heard about Fujitsu 80387 FPUs, or do you think it's something else?

Genna

[CPUShack]

I've never heard of one but if soldered to the same connections it is hard to be much else. Could be a second source.

there isnt much that can interface the same way as a FPU. I tyhink you may have found something there.

[fRaSsL]

Seems that the make it 486 module with Cyrix CPU is a completely different revision. There is the driver IC missing in the upper right corner. Maybe they changed the design?
The copro on the pcb doesn't make much sense, because most of the boards already have a copro socket. Maybe Improve Technologies saw that too and left the copro?!

[gshv]