Thanks. Fulfilling this by configuring ntp.conf sounds quite diable. I followed some instructions online but failed. Here is what in BBG's ntp.conf and Pi's ntp.conf. I use 192.168.0.102 to ssh into pi and 192.168.4.2 to ssh into BBG.
Part of ntp.conf in BBG: # pool.ntp.org maps to about 1000 low-stratum NTP servers. Your server will # pick a different set every time it starts up. Please consider joining the # pool: <http://www.pool.ntp.org/join.html> server 192.168.0.102 Part of ntp.conf in Pi: # By default, exchange time with everybody, but don't allow configuration. restrict -4 default kod notrap nomodify nopeer noquery limited restrict -6 default kod notrap nomodify nopeer noquery limited restrict 192.168.4.0 mask 255.255.255.0 nomodify notrap And here is the result for ntpq -p on BBG. I don't know how to check if BBG is really trying to make time sync. debian@beaglebone:~$ sudo ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== 192.168.0.102 .XFAC. 16 u 58 64 0 0.000 0.000 0.000 在 2020年7月2日星期四 UTC-4下午4:11:07，[email protected]写道： > > Setup NTP server on the pi. > The BBB should have the ntpd (NTP daemon) already setup. Change the ntp > configuration to point to the IP of your pi. > Let ntp maintain the time by itself no need for cron. Any scripts or > custom implementation will had a delay which will increase the time drift > between your systems. > > To maintain the clock between reboots or when the pi is unavailable, > purchase an i2c real time clock like the DS1307 and use ntp to keep the > time sync'ed. > > I hope this helps. > > On Thursday, July 2, 2020 at 9:27:23 AM UTC-7, [email protected] wrote: >> >> Yeah, GGB has its own power supply. And I am connecting raspberry pi and >> BBG through ethernet. For transmitting the message, it is done by LCM. >> I think LCM is faster because at least there's no password issue and I >> hope to let the BBG time sync quite often(like every 1 min), but not too >> often because that would be unnecessary. >> >> What I now have is a program(c or python) that can get the time sending >> by a raspberry pi. Now I plan to read the output and set the time using >> think command: date -s "2 OCT 2006 18:00:00" >> in the shell script. But I don't know how to do that. >> >> >> 在 2020年7月2日星期四 UTC-4上午11:03:20，Dennis Bieber写道： >>> >>> On Wed, 1 Jul 2020 22:45:25 -0700 (PDT), in >>> gmane.comp.hardware.beagleboard.user >>> [email protected] wrote: >>> >>> >Hi, >>> > >>> >I am doing a project using both beaglebone and raspberry pi. Now only >>> the >>> >pi has internet connection and I have to sync their time. Currently I >>> can >>> >send the pi's time to beaglebone green every second, but I don't know >>> how >>> >to use this data to set the system time on Beaglebone. I plan to write >>> a >>> >shell script so it can be running all the time from boot. Anyone knows >>> how >>> >to do that? Thanks. >>> > >>> >>> "Information... We want... Information" >>> >>> How is the BBG connected to the R-Pi for this transfer? If the >>> R-Pi is >>> sending time data, there has to be something on the BBG that is reading >>> it. >>> >>> It would probably be easier to have the BBG /ask/ the R-Pi for >>> the >>> time, and that could be done using a cron job on the BBG. Of course, >>> that >>> means now the R-Pi has to have running process to accept the requests... >>> >>> It all comes down to how the two devices are communicating. If >>> the BBG >>> is connected to the R-Pi via USB (hope you are using an external power >>> supply on the BBG -- don't think an R-Pi USB can provide the power draw) >>> you might just need to configure the R-Pi as a gateway, and let the BBG >>> NTP >>> (or whatever recent Debian/systemd sets up) do normal time sync through >>> the >>> R-Pi's network connection (or run a tier 3 NTP server on the R-Pi and >>> let >>> the BBG time sync to it). >>> >>> >>> -- >>> Dennis L Bieber >>> >>> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/e62435e5-7329-4d48-b726-b728df506580o%40googlegroups.com.
