Real Time Clock RTC

Adding a RTC to the Hive Interface board.

• 

  DS3231 RTC

• Error creating thumbnail: File missing

  Installed on a Pi

DS3231

Hardware

This module almost plugs in to H2 (the I2C bus) on the Hive Interface board. A minor modification is required. As +5 VDC is not used and the ground must be shifted down a pin:

1. The ground on C? must be moved.
2. To be safe, the 4th pin of a 1x5 male header should be removed.
3. Solder the 1x5 header in H2 BUT SHIFT IT DOWN ONE PIN.

H2 I2C Bus
Pin	Signal	New H2 for RTC
1	+5	No connect
2	+3.3	Pin 1 of H2
3	I2C	Pin 2 of H2
4	I2C	Pin 3 of H2
5	Ground	No connect
Ground for C	Ground	Pin 5 of H2

Software

These instructions work, but are not complete in that the RTC is not set to the ntp servers when ntp servers are available:

https://learn.adafruit.com/adding-a-real-time-clock-to-raspberry-pi/overview

These instructions appear to be better but I have not tested them: https://www.raspberrypi.org/forums/viewtopic.php?t=85683

sudo raspi-config 

Select

5 Interfacing Options 

Select

P5 I2C

and enable it.

sudo apt-get update
sudo apt-get install python-smbus i2c-tools

This wasn't necessary as they were both installed and latest version.

Edit /boot/config.txt. Add:

#enable RTC DS3231 module
dtoverlay=i2c-rtc,ds3231

Edit /lib/udev/hwclock-set and comment out these three lines:

#if [ -e /run/systemd/system ] ; then
# exit 0
#fi