[time-nuts] source for ICS525 demo board ...

Tim Shoppa shoppa at trailing-edge.com
Fri Feb 17 06:40:27 EST 2006


"Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
> In message <43F55F52.40102 at cloudview.com>, John Pettitt writes:
> >I've been toying with the idea of replacing the crystal in one of my
> >soekris 4801's (it's 27Mhz for the Geode processor) with a signal
> >synthesized from the 5Mhz GPS disciplined output of my TrueTime box -
> >the ICS525 looks like a good part to use to do the work and I was
> >wondering if anybody has used this part in a project and can point at a
> >good source for the demo board with seems to be a quick and dirty way of
> >implementing what I want ....
>
> Apart from bugging ICS a lot, I know of no source.

Hate to be a nagger, but it's not that hard to lock to a reference
using stone knives and bearskins. (Well, TTL and a LC
VCO with a varactor diode for tuning. Today you'd use HC TTL of
course.)

PLL's become hairy when you have low reference frequencies
and need long programmable dividers. Here the reference frequency would
be 1 MHz, right? So we need a divide-by-5 and a divide-by-27 and
a phase comparator.

Dead-bug construction would be perfect.

Tim.





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