Sunday, September 10, 2017
Getting DS1307 on RPI3 with fedora 24
1 - Add in the /boot/config.txt:
dtoverlay=i2c-rtc,ds1307
In dmesg:
+++
[ 5.536541] rtc-ds1307 1-0068: rtc core: registered ds1307 as rtc0
[ 5.540786] rtc-ds1307 1-0068: 56 bytes nvram
+++
the modules are loaded a boot now...
+++
[root@pc-8 ~]# i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
+++
[root@pc-8 ~]# hwclock -r
2017-09-09 17:58:49.868784+1:00
(well not too bad after 2 months (+~1 minute)
2 - Get chrony to resynchronize my hardware clock (if I have a connection!)
In /etc/chrony.conf:
+++
# Enable kernel synchronization of the real-time clock (RTC).
rtcsync
# Serve time even if not synchronized to any NTP server.
local stratum 10
+++
dtoverlay=i2c-rtc,ds1307
In dmesg:
+++
[ 5.536541] rtc-ds1307 1-0068: rtc core: registered ds1307 as rtc0
[ 5.540786] rtc-ds1307 1-0068: 56 bytes nvram
+++
the modules are loaded a boot now...
+++
[root@pc-8 ~]# i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
+++
[root@pc-8 ~]# hwclock -r
2017-09-09 17:58:49.868784+1:00
(well not too bad after 2 months (+~1 minute)
2 - Get chrony to resynchronize my hardware clock (if I have a connection!)
In /etc/chrony.conf:
+++
# Enable kernel synchronization of the real-time clock (RTC).
rtcsync
# Serve time even if not synchronized to any NTP server.
local stratum 10
+++
3 - Get the hard clock set at the RPI3 start time:
creates a /etc/systemd/system/hwclock.service
+++
[Unit]
Description=Setup date and time via hwclock
[Service]
Type=oneshot
ExecStart=/usr/sbin/hwclock --hctosys
[Install]
WantedBy=multi-user.target
+++
and do:
systemctl enable hwclock
System time is set corrctly...
+++
[root@pc-8 ~]# timedatectl status Local time: Sat 2017-09-09 19:35:58 CEST
Universal time: Sat 2017-09-09 17:35:58 UTC
RTC time: Sat 2017-09-09 17:35:58
Time zone: Europe/Zurich (CEST, +0200)
Network time on: yes
NTP synchronized: no
RTC in local TZ: no
+++
Don't forget the firewall...
firewall-cmd --permanent --zone=FedoraServer --add-port=123/udp
firewall-cmd --reload
4 - make sure the clients (HypriotOS in my case) use the time server:
Add the RPI3 address in /etc/systemd/timesyncd.conf for (here 10.0.0.201 is the RPI3 with the hardware clock):
+++
[Time]
Servers=10.0.0.201
+++
service systemd-timesyncd restart
