Re: Accelerating the PCT

[dempson@actrix.gen.nz (David Empson)]

Edhel Iaur, Esq. <drsmooth@relex.com> wrote:

> dempson@actrix.gen.nz (David Empson) wrote:
> 
> ><pubpc17@library.ucla.edu> wrote:
> 
> >> I finally had to try it.  I replaced the 16MHz oscillator on the PCT
> >> board with a socket and experimented.  The bad news is that this clock
> >> does not seem to regulate the processor speed.  It is tied into the
> >> PCT's video.
> 
> >According to the manual, the PCT's processor runs at 7.14 MHz.  This is
> >suspiciously close to the frequency of the 7M signal which is available
> >on the slot connector (in the IIgs or US version of the IIe, 7M is half
> >of 14.31818 MHz, i.e. 7.15909 MHz).
> 
> So to get, say 200 MHz, we'd hafta get a 486 DX-28 200?  ;D

Yes, and you'd also have to run the Apple II motherboard at 400 MHz,
because the PCT's processor is driven off a clock which is running at
half the Apple II's master clock frequency.  

Does anyone have a 30 MHz 6502 and 5 ns dynamic RAM?  ;-)

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand