[time-nuts] Holdover, RTC for Pi as NTP GPS source

Hal Murray hmurray at megapathdsl.net
Thu Nov 2 01:12:57 EDT 2017

tpiepho at gmail.com said:
> Forget about accurate time from the RTC's registers.  The slowness and
> variably in I2C is quite poor and most of them don't even have sub-second
> resolution when read or written. 

If your RTC has a PPS output, you can read the registers to get the coarse 
time, then wait for the PPS to tick to get the low order bits.

These are my opinions.  I hate spam.

More information about the time-nuts mailing list