I have had DS3231 RTC's on my Pi's running Wheezy, Jessie and now Stretch. Everything worked as expected on Wheezy and Jessie but Stretch has a problem I haven't been able to figure out.
I followed the instructions here for Jessie and Stretch. https://learn.adafruit.com/adding-a-rea ... t-rtc-time
and also installed NTP using DougieLawson post in this thread viewtopic.php?t=194468
which is ...
sudo apt install ntp
sudo systemctl enable ntp
sudo timedatectl set-ntp 1
When the pi is first booted the RTC time always shows Thu 2016-11-03 17:17:15 (give or take a few seconds)
Local time: Thu 2018-03-15 16:29:38 CDT
Universal time: Thu 2018-03-15 21:29:38 UTC
RTC time: Thu 2016-11-03 17:17:15
Time zone: America/Chicago (CDT, -0500)
Network time on: yes
NTP synchronized: yes
RTC in local TZ: no
After a few minutes the RTCs will get their time set correctly, but it's always wrong at boot.
Since I have 9 raspberry pi's of different versions that all do the exact same thing, it has to be software.
Thanks for any help, Max