[time-nuts] verifying synchronization with PPS

[folkert]

> Folkert van Heusden has a driver for NTP which includes PPS output:
>  https://vanheusden.com/time/rpi_gpio_ntp/
> Perhaps this might help?

Indeed I did! :-)

But please note that the jitter is high, iirc around 18ms.
Personally I would use https://github.com/mlichvar/pps-gpio-poll.git and
then patch it toggle an other gpio-pin.