[time-nuts] PICPET- was Affordable (cheap) COTS (etc)

[paul swed]

Good thread.
Yes I am very aware of the parallax propeller. As you both say kind of a
crazy chip. I have used another product the SXB micros. They run Basic at
80 Mhz and are so cheap that If I have more than a few chips I just switch
over. Unfortunately they are obsolete in the dip form. When I looked at the
propeller my take away was that it was such an odd chip I actually did not
want to deal with it figuring its life was just a few years. Its advantage
was the ability to have so many things running in parallel.

The great thing about the PICs are there are such a wide diversity of them
at really cheap prices. Tom thanks for the insight on the synchronous
clock. Did not realize that.
Regards
Paul
WB8TSL


On Thu, Jan 23, 2014 at 4:00 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

> > Has anyone else looked at the Parallax Propeller processor for timing
> > functions?
>
> Hi Brian,
>
> Oh yes. Really nice chip. But for precise timing applications I had huge
> problems with phase and temperature stability of its internal PLL. I tried
> half a dozen different boards purchased over several years. Tech support
> was not interested in someone who worried about nanoseconds.
>
> The architecture is really interesting, but it is such an odd chip, with
> almost zero market visibility these days, that I set aside the goal of
> using it as the basis of a general purpose 8-channel 6 ns precision
> counter. You can find various timer and counter examples at
> obex.parallax.com. If you make progress on the project, please let me
> know, ok?
>
> By contrast, the PIC chips I use are fully synchronous so when you use 10
> MHz atomic references the clock/output jitter and phase stability is almost
> below what I can measure here. Maybe under 2 ps. So that's why I use PIC's
> as the basis of all my picDIV and picPET projects. But I'm open to using
> something different in the future.
>
> /tvb
>
>
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