🚀 go-pugleaf

In article <TMH.92Jul22194404@keks.first.gmd.de> tmh@keks.first.gmd.de (Thomas Hoberg) writes:
>In article <3713@svin02.info.win.tue.nl> debra@wsinis07.info.win.tue.nl (Paul De Bra) writes:
>   In article <RFowler.288@kelvin.jpl.nasa.gov> RFowler@kelvin.jpl.nasa.gov (Robert A. Fowler) writes:
>   >In comp.ibm.pc.hardware there is a thread about weather the 486DX uses a 1x 
>   >or a 2x clock.  I (perhaps mistakenly) said it used a 2x clock, (all of the 
>   >motherbords I've seen had a 2x occilator) could some one with a real data 
>   >book clarify?
>
>   The 386 uses a 2x clock, whereas the 486 uses a 1x clock.
>   A 2x clock has the advantage of delivering a perfectly symmetrical
>   1x clock after halving. A 1x clock needs better clock circuitry to
>   make sure it is symmetrical.
>
>Hmm, I was always under the impression that even the 486 used a 2x
>clock up until the 486DX[2]50, which uses a 1x clock. Anyway I have a
>66MHz oscillator on my 486/33 motherboard.
>---
I'm looking at page 2-177 of the 1992 Intel Microprocessor data book

For the 50 MHz 486 part the minimum input frequency is 16MHz, and the
maximum input frequency is 50MHz.  There is a note for this saying that
it is a 1x CLK to Intel 486.  The spec also calls for the clock symetry
to be no worse than 56-44, with .1% stability.

For those out there with a 2x oscillator on the motherboard, it is likely
that the support chip set needs the 2x, cause the CPU don't.....