VOGONS

80287 XL questions

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First post, by snorg

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Does anyone know if the 80287 XL can be used with a 286 cpu, or was it only meant to be used with a 386 system until proper 387 FPUs were developed? To the best of my knowledge, the 80287 XL is an FPU with a pinout for a 287 socket but internally is a 387 fpu. Wikipedia did not indicate whether it could be used with either, the entry seemed to imply it was meant for 386 systems only.

Reply 1 of 2, by Jo22

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I think it essentially was a 387SX with a 287 pinout.
So yes, that one should work just fine with a 286 system also.
But that's just my opinion.
I was already lucky to get hold of a ceramic i287 (non-XL, very hot) for my 80286.
A modern XL type was out of my reach so far.

Maybe you get a more precise answer for this from the Amiga community (or other Vogons people):
They used to have 286-based bridge board cards for their machines (esp. the A2000/A1500 models).
Same for Atari ST's - 286-based PC emulators were very popular there, even after 386 PCs were common.
It's likely that these PC emulators got upgraded with the more modern 287XL chips (the non-XL chips were too slow and outdated by that time).

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 2 of 2, by Anonymous Coward

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The 80287XL works in 286 motherboards, or with very old 386 motherboards that have 287 sockets.

However, it does not seem to be compatible with some 286 to 486 upgrade adapters such as "Make it 486".

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

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