RaspBee II RTC

RTC kernel module builder for RaspBee II

This repository provides a Makefile which downloads, builds and installs the RTC kernel module for the RaspBee II Zigbee shield for Raspberry Pi.

The RTC is not mandatory for the use of the RaspBee II as a ZigBee coordinator.

When the linux kernel gets updated it can happen that the RTC module build fails because it takes some time until the raspberry pi kernel headers package is updated with the new version. In this case you can repeat the build in a few days. Or get your kernel version from somewhere else (rpi-source) or try use a workaround described below.

Dependencies

Hardware

Raspberry Pi 1, 2B, 3B, 3B+ or 4B
RaspBee II Zigbee shield
FW version 26610700 or higher (http://deconz.dresden-elektronik.de/deconz-firmware/deCONZ_RaspBeeII_0x26610700.bin.GCF)

Supported platforms

Raspbian Stretch or Buster

Install

Update Raspberry Pi and Reboot
```
sudo apt update
sudo apt upgrade
reboot
```

Install dependencies

sudo apt install i2c-tools build-essential raspberrypi-kernel-headers

Download installation archive

curl -O -L https://github.com/dresden-elektronik/raspbee2-rtc/archive/master.zip
unzip master.zip

Change into extracted directory
```
cd raspbee2-rtc-master
```
Compile RTC kernel module
```
make
```
Install RTC kernel module
```
sudo make install
```
Reboot Raspberry Pi
```
sudo reboot
```
Configure system time to RTC module
```
sudo hwclock --systohc
```

Test that RTC is working

sudo hwclock --verbose

Waiting in loop for time from /dev/rtc0 to change
...got clock tick
Time read from Hardware Clock: 2020/03/06 13:55:21
Hw clock time : 2020/03/06 13:55:21 = 1583502921 seconds since 1969
Time since last adjustment is 1583502921 seconds
Calculated Hardware Clock drift is 0.000000 seconds
2020-03-06 14:55:20.017097+01:00

timedatectl

Local time: Fri 2020-04-03 12:42:20 CEST
       Universal time: Fri 2020-04-03 10:42:20 UTC
             RTC time: Fri 2020-04-03 10:41:56
            Time zone: Europe/Berlin (CEST, +0200)
       System clock synchronized: no
          NTP service: inactive
      RTC in local TZ: no

Troubleshooting

If something went wrong during install please consider the following error sources:

Install dependencies
Execute make without sudo
Execute make install with sudo
If behind a proxy make sure it is correctly configured

If you get Error Message like

make -C /lib/modules/6.1.21-v8+/build M=/home/openhabian/raspbee2-rtc-master modules
        make[1]: *** /lib/modules/6.1.21-v8+/build: File or directory not found.  Exit.
        make: *** [Makefile:17: build] Error 2

try adding "arm_64bit=0" to config.txt, (disables 64bit) reboot and try again
or link your kernel version lib/modules directory to existing kernel header directory in /usr/src

ls -l /usr/src
sudo ln -s /usr/src/linux-headers-6.6.20+rpt-rpi-v7l /lib/modules/$(uname -r)/build

Use the RTC

Set RTC time to system time: \ sudo hwclock --systohc

Read the RTC time: \ sudo hwclock -r

For more information see: https://linux.die.net/man/8/hwclock

dresden-elektronik / raspbee2-rtc

readme