[time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

Paul tic-toc at bodosom.net
Sun Aug 14 19:10:42 EDT 2016


On Sun, Aug 14, 2016 at 12:37 PM, STR . <strykar at hotmail.com> wrote:
> COM2 has headers and seemed like an obvious choice as I have no real need
for a 2nd serial port.

COM2 does not have control lines.  Unless you're going to rewrite the PPS
kernel module you have to use COM1 or GPIO.  Sadly GPIO is not plug and
play. However it's not impossible.  Someone on the PCEngines forum may have
done it already.

>From the doc pages 8/9.
J3 COM2 3.3V serial port (RXD / TXD only).
...
J22 COM1 Serial port. Full handshake signals this time...


P.S.
Pascal's comment about jitter is not relevant to normal NTP.

--
Paul


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