Difference between revisions of "NTP"
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==Time synchronisation from GPS== | ==Time synchronisation from GPS== | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! Buildroot !! Debian | ||
| + | |- | ||
| + | | | ||
* You will need the "real" NTP daemon, not the Busybox one. | * You will need the "real" NTP daemon, not the Busybox one. | ||
| − | * | + | || |
| + | <pre class="apf"> | ||
| + | root@opos6ul:~# apt-get install ntp | ||
| + | </pre> | ||
| + | |} | ||
| + | |||
| + | * Edit/Replace config file (''/etc/ntp.conf'') with: | ||
<pre class="apf"> | <pre class="apf"> | ||
# Allow only time queries, at a limited rate, sending KoD when in excess. | # Allow only time queries, at a limited rate, sending KoD when in excess. | ||
| Line 24: | Line 35: | ||
* ''mode 17'' is for 9600 bauds GPS providing GPRMC frames | * ''mode 17'' is for 9600 bauds GPS providing GPRMC frames | ||
| − | * To create /dev/gpsX (GPS is connected to UART2): | + | * To create /dev/gpsX (here GPS is connected to UART2): |
<pre class="apf"> | <pre class="apf"> | ||
# ln -sf /dev/ttymxc1 /dev/gps0 | # ln -sf /dev/ttymxc1 /dev/gps0 | ||
</pre> | </pre> | ||
| − | * To launch ntpd: | + | * You can add the previous in ntpd start script (''/etc/init.d/ntp''): |
| + | <source lang="diff"> | ||
| + | --- /etc/init.d/ntp | ||
| + | +++ /etc/init.d/ntp | ||
| + | @@ -59,6 +59,7 @@ | ||
| + | exit 1 | ||
| + | fi | ||
| + | lock_ntpdate | ||
| + | + ln -sf /dev/ttymxc1 /dev/gps0 | ||
| + | start-stop-daemon --start --quiet --oknodo --pidfile $PIDFILE ---startas $DAEMON -- -p $PIDFILE $NTPD_OPTS | ||
| + | status=$? | ||
| + | unlock_ntpdate | ||
| + | |||
| + | </source> | ||
| + | |||
| + | * To launch ntpd (if not automatically launched at startup): | ||
<pre class="apf"> | <pre class="apf"> | ||
# /usr/sbin/ntpd -g -c /etc/ntp.conf | # /usr/sbin/ntpd -g -c /etc/ntp.conf | ||
| Line 39: | Line 65: | ||
[[Category:Time]] | [[Category:Time]] | ||
[[Category:NTP]] | [[Category:NTP]] | ||
| + | [[Category:GPS]] | ||
Latest revision as of 15:19, 31 May 2017
From https://en.wikipedia.org/wiki/Network_Time_Protocol, "Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks." Practically, it allows you to have current time/date on your APF even if your don't have an RTC (you will need an Internet connection or a GPS ;-)).
Get current Time from Internet
# ntpd -nqp 217.147.208.1
Time synchronisation from GPS
| Buildroot | Debian |
|---|---|
|
root@opos6ul:~# apt-get install ntp |
- Edit/Replace config file (/etc/ntp.conf) with:
# Allow only time queries, at a limited rate, sending KoD when in excess. # Allow all local queries (IPv4, IPv6) restrict default nomodify nopeer noquery limited kod restrict 127.0.0.1 restrict [::1] server 127.127.20.0 mode 17 minpoll 4 maxpoll 4 prefer fudge 127.127.20.0 flag3 1 flag2 0 flag1 1 time1 0.0
- 127.127.20.0 means: "use /dev/gps0 and parse it as NMEA to get time" (See [1]).
- mode 17 is for 9600 bauds GPS providing GPRMC frames
- To create /dev/gpsX (here GPS is connected to UART2):
# ln -sf /dev/ttymxc1 /dev/gps0
- You can add the previous in ntpd start script (/etc/init.d/ntp):
--- /etc/init.d/ntp
+++ /etc/init.d/ntp
@@ -59,6 +59,7 @@
exit 1
fi
lock_ntpdate
+ ln -sf /dev/ttymxc1 /dev/gps0
start-stop-daemon --start --quiet --oknodo --pidfile $PIDFILE ---startas $DAEMON -- -p $PIDFILE $NTPD_OPTS
status=$?
unlock_ntpdate
- To launch ntpd (if not automatically launched at startup):
# /usr/sbin/ntpd -g -c /etc/ntp.conf
