Hi David,

> That sounds good, Folkert - perhaps you might publish the details
> somewhere? I'd like to try it myself, but my Linux and C knowledge
> is limited.

Here it is:
http://vanheusden.com/time/rpi_gpio_ntp/

Please let me know if anything is unclear: I'll then enhance e.g. the
readme.txt and such.

> For comparison, on three RPi cards here with modified kernels to get
> PPS from a GPIO pin, using ntpq -pn I see jitter values of 0.002,
> 0.002 and 0.002/0.004.  The 0.002 seems to be near the sys_jitter
> limit as reported from ntpq -c rv.

That's indeed better. The results I see are probably also influenced by
the fact that this RPI also does other things (software defined radio,
camera and measuring the light intensity outside).

> Cards 1 and 2 are just doing NTP, the third card is running a data
> collector processing signals from a DVB receiver stick, and sending
> the derived data over a Wi-Fi link to a PC running Plane Plotter
> using the dump1090 program. This gives a CPU load around 35%.  It
> would be interesting to know how your version handles a busy RPi.

Hmmm, I'll see if I can setup an RPI which only does the time keeping
and see if that gives better results.


Folkert van Heusden

-- 
MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san
den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti
kroru, tya kon makandra, nanga wan lo moro.
http://www.vanheusden.com/multitail/
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