OT - 486 w/newer IDE drives

[Chuck Guzis]

On 23 Nov 2006 at 14:01, Tothwolf wrote:

> Actually, the early 486SX dies were fully working 486DX parts. They just 
> had a different pinout and no bond wires were installed for the FPU. Intel 
> did ship later 486SX chips that were made from dies with defective FPUs.

As I understand it, Intel on the early -20 486s had a yield problem 
with the FPU circuitry.  So the 486sx was born.  NMI* was moved from 
B15 to A15 and and FERR* and IGNNE*  weren't bonded out.  Later 486s 
(the -25 and -33) had no NDP on the die.

The 487 has the same pinout as the 486DX with the exception of 
bringing MP* out to B14 (nc on the 486SX) and FERR* out to A13.  As I 
understand it, the 487sx was essentially a fully-functional 486DX 
under the clay.

Cheers,
Chuck