[time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

[Scott Stobbe]

For pulse counting, the timer hardware is the way to go. Setup a 16-bit
timer clocked off your DUT. Then input capture on your PPS edge. This
leaves you plenty of processor time for string formatting and other tasks
you may wish to perform.

If you do the decimation as post-processing on your PC (i.e. log cycle
count every PPS), you can use a zero-phase moving average filter, which may
provide more visual insight over just a single data point every 1000s.

On Tue, Jun 28, 2016 at 3:48 PM, Hal Murray <hmurray at megapathdsl.net> wrote:

>
> pete at heypete.com said:
> > I have seen those, but I have little experience with PICs and the Wife
> > Acceptance Factor of buying more stuff for a one-off measurement is low.
>
> The PIC family is very similar to AVRs.  The picPET and friends are 8 pin
> DIPs so the Wife is unlikely to notice the additional clutter.
>
>
> >> The PPS input on a PC may be be useful.
> > Indeed. I normally use it for NTP.
>
> Than you want a second serial port for things like this.
>
> Or maybe you can use the parallel port if your system is old enough to have
> one.  I haven't tried it, but I think Linux has a module that supports it.
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>