[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

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.


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