hmurray at megapathdsl.net
Sat Jan 27 22:52:55 UTC 2018
devel at ntpsec.org said:
> As far as I understand the sources, setting up an echo allows a PPS client
> to register a callback function with the PPS device to be called when a PPS
> event happens. The default echo function simply outputs "echo: assert" or
> "echo: clear". I guess one could indeed toggle a GPIO from a suitably
> defined PPS client.
It may be easier to experiment with a real serial port since it would be easy
to pick one of the output modem control signals.
With gpio we could make the dtoverlay line take 2 pin numbers. It shouldn't
be a big deal, but it's another complication. As a hack, we could just use
the next pin number. I think the hardware is safe if you pick a wrong pin
number. If the dtb isn't setup right, the gpio bit isn't connected to the
The other hack we would need to to is patch the code in ntpd that sets up the
PPS stuff not to turn off the edge it doesn't need so the output pin can get
reset to be ready for the next time.
These are my opinions. I hate spam.
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