Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Regarding Linux on Arm, I'd suggest opensuse. The opensuse arm forum was the only one that actually helped me. While they have an official list of boards they support, they will help on pretty much any Arm board out there. You can't reach anyone of authority at Ubuntu. You can get help, but bug fixes are another story. Fedora is hopelessly behind on Arm. Opensuse has dipped their toes in embedded linux for some time, so Arm isn't a stretch for them. I believe they are serious about Arm. I have openuse running on a Beagleboard XM. About the only thing that wasn't working was mono. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
What sort of nanosecond timing PPS interface is available on these boards? I don't mind hacking a kernel with some oddball PPS patch, but I haven't done that for years, and if someone told me that distro X worked well with PPS interface Y out of the box, that would be a big win. I still don't trust USB for precise PPS timing but folks could convince me different. Doubt GPIO14 would get there either but I could be educated there too. Tim N3QE On Wed, Jul 3, 2013 at 3:00 PM, folkert folk...@vanheusden.com wrote: Here's a review of several small low power linux systems: http://www.cooking-hacks.com/index.php/blog/new-linux-embedded-devices-comparison-arduino-beagleboard-rascal-raspberry-pi-cubieboard-and-pcduino Folkert van Heusden -- MultiTail is a versatile tool for watching logfiles and output of commands. Filtering, coloring, merging, diff-view, etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
tsho...@gmail.com said: I still don't trust USB for precise PPS timing but folks could convince me different. Doubt GPIO14 would get there either but I could be educated there too. USB is probably good enough for ms level timing. I haven't looked carefully at the details of the chips used in any of the boards discussed recently. Several years ago, I worked with ARM SOCs. These were the ones designed to run out of on-chip RAM and flash rather than external memory. The limitation was pins. The chips had more IO devices than there were pins for. Each pin had 2 or 3 possible uses. If you were considering using a chip, you had to do more than just check the summary info sheet to make sure in had enough timers, UARTs and whatever you needed. You also had to make sure that you could find a pinout assignment that wouldn't conflict. With that in mind, there are two possible ways to get PPS timing into one of those chips. 1) You could get an interrupt on a GPIO pin and save the time, just like the traditional PPS on a modem control signal. 2) You could find an unused GPIO pin that is connected to a previously unused counter/timer and set things up to latch the count when the level changes. ... -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
One possibility is that the CPU is getting turned off when idle to save power. If that includes the stuff normally used for timekeeping, things could get screwed up when it gets turned back on. It has to reset the time, probably getting it from the RTC. I don't think this is the case. Look at how well the system to sync'd with other NTP servers. It is only the local GPS ref. clocks that are not doing well. Also you might check the NMEA output by some other means, some Garmin units are really bad. If you can turn off all the un-needed NMEA sentences it might help. Simply watching the NMEA output in a terminal window is a good enough check. You can see by eye if there is a one second error -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
Oh for convenience. I need to patch ntpd to use linux pps (afaik) and on other systems I successfully run gpsd with ntpd (read: low jitter). Using gpsd with ntpd reduces the jitter versus just using ntpd by itself? No I meant that running that combination is successfully because I see low jitter. Folkert van Heusden -- Multitail est un outil permettant la visualisation de fichiers de journalisation et/ou le suivi de l'exécution de commandes. Filtrage, mise en couleur de mot-clé, fusions, visualisation de différences (diff-view), etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
At the risk of hijacking a thread, shooting of the subject and just generally bad etiquette for news group posting, I am running all my S1 NTP servers on HP thin clients! They only draw ~14 watts of power. I have managed to fit a 3.5 inch laptop drive in the T150's so they run a (minimal text based) full version of centos. And the serial port seems to be okay: NTP 1 running of a HP 58534A integrated timing antenna: State Remote Refid Stratum TypeWhenPollReach Delay Offset Jitter o 127.127.20.0GPS 0 Local clock 8 16 377 0.000 -0.001 0.002 NTP2 running off an Acutime (hmm, marketing) Gold: State Remote Refid Stratum TypeWhenPollReach Delay Offset Jitter * 127.127.29.0GPS 0 Local clock 2 32 377 0.000 0.166 0.005 I Don't know about Load handling, I farm most of the NTP requests off to a Stratum 2 (well technically S3 as GPS PPS is not true stratum 1, please correct me if I am wrong?) But works well for me, I'd love to find a ref driver for the Z3805A port 2 even second string... Perhaps using the parse driver w/ PPS refclock (is possible?) Anyway, there is my 0.02c :p -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Iain Young Sent: Tuesday, 2 July 2013 4:14 PM To: time-nuts@febo.com Subject: Re: [time-nuts] looking for low-power system for gps ntp timekeeping On 02/07/13 06:43, NeonJohn wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. You are not restricted to just Angstrom. My fleet run Debian. FreeBSD is also available. First thing I do is blow away Angstrom from any SD card. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. Hmm, is this a case of Angstrom being beind the kernel curve, or is it still an issue when running things like Debian ? I've not had the need to use SPI on the BB yet, only the Pi. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. I've only ever had one SD card go dead on me on my entire fleet, and I suspect that was actually my fault, not Debian's :) A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. I've heard he can be somewhat robust to deal with. That said, he is very knowledgeable from what I've seen/understand. Never actually had to mail the mailing list itself though - found all the answers I needed in the archive - often from him! PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. Hmm. I checked a lot of the things I'd need on the black for this type of application, and found they were all still there (Serial Ports, PRUSS, Timers etc). Yes you may need to twiddle the pinmux as by default it goes to he HDMI stuff etc, but they are still there Is there something specific here you are thinking of ? Maybe I just don't need what they left off. I do remember looking and going Meh, not important for what I'm doing Best Regards Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
Hi, I decided to buy a Nanos G20. Not too expensive, real serial port, debian linux pre-installed. I don't want to sound harsh as the people from Nanos probably did their best to produce a good product, but for timekeeping it is totally crap and also useless. Well, unless I did something wrong. I recompiled the kernel to enable PPS support, installed gpsd and ntpd, configured at all and let it run for a while. allan deviation: http://keetweej.vanheusden.com/~folkert/nanosg20/allandev.png offset: http://keetweej.vanheusden.com/~folkert/nanosg20.png remote refid st t when poll reach delay offset jitter == x127.127.28.0.NMEA. 0 l3 16 3770.000 -994.05 7.857 x127.127.28.1.PPS.0 l7 16 3770.000 -250.13 572.812 +192.168.64.18 .PPS.1 u 66 128 3770.553 -0.055 0.033 *192.168.64.2.PPS.1 u 99 128 3770.237 -0.062 0.039 +192.168.64.168 .PPS.1 u 44 128 3770.646 -0.013 0.321 Folkert van Heusden -- MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti kroru, tya kon makandra, nanga wan lo moro. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
There are many ways to solve the SD card problem. One is to write the file to a networked disk drive, or set up a disk image in RAM, but then you loose the data if the power fails or you can use a small notebook disk in place of the SD card. You could write to the SD card in batches, say one batch per hour or per day. Set up a cron job to transfer files from the RAM based disk image to the card. On Tue, Jul 2, 2013 at 12:11 PM, Didier Juges shali...@gmail.com wrote: John, The SD Card issue is serious but not unique go the BBB. I believe there are ways to configure any Linux distro to make the SD card read only, at the cost of losing logging and data every time you power off. Alternately, one could partition the SD card with a second partition just for data you want to save. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
folk...@vanheusden.com said: remote refid st t when poll reach delay offset jitter == x127.127.28.0.NMEA. 0 l3 16 3770.000 -994.05 7.857 x127.127.28.1.PPS.0 l7 16 3770.000 -250.13 572.812 +192.168.64.18 .PPS.1 u 66 128 3770.553 -0.055 0.033 *192.168.64.2.PPS.1 u 99 128 3770.237 -0.062 0.039 +192.168.64.168 .PPS.1 u 44 128 3770.646 -0.013 0.321 Something is broken. What NMEA device are you using? Why are you using gpsd rather than ntpd's NMEA driver? It looks like the NMEA side it is off by a second. Some devices do that. You can fix that with some fudging. The PPS stuff is off by 250 ms. Are you using the wrong edge? (Got a scope handy?) -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Here's a review of several small low power linux systems: http://www.cooking-hacks.com/index.php/blog/new-linux-embedded-devices-comparison-arduino-beagleboard-rascal-raspberry-pi-cubieboard-and-pcduino Folkert van Heusden -- MultiTail is a versatile tool for watching logfiles and output of commands. Filtering, coloring, merging, diff-view, etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
Hi, I decided to buy a Nanos G20. Not too expensive, real serial port, debian linux pre-installed. I don't want to sound harsh as the people from Nanos probably did their best to produce a good product, but for timekeeping it is totally crap and also useless. Well, unless I did something wrong. I recompiled the kernel to enable PPS support, installed gpsd and ntpd, configured at all and let it run for a while. allan deviation: http://keetweej.vanheusden.com/~folkert/nanosg20/allandev.png offset: http://keetweej.vanheusden.com/~folkert/nanosg20.png remote refid st t when poll reach delay offset jitter == x127.127.28.0.NMEA. 0 l3 16 3770.000 -994.05 7.857 x127.127.28.1.PPS.0 l7 16 3770.000 -250.13 572.812 +192.168.64.18 .PPS.1 u 66 128 3770.553 -0.055 0.033 *192.168.64.2.PPS.1 u 99 128 3770.237 -0.062 0.039 +192.168.64.168 .PPS.1 u 44 128 3770.646 -0.013 0.321 Folkert van Heusden == Folkert, Thanks for your graphs, but what are the Y-axis units! Inn your billboard above, the PPS looks to be on the wrong edge - perhaps the pulse is 250 ms wide and you are syncing to the trailing edge and not the leading. Can you check that out? I recall that it's the positive going transition on the DCD connection which needs to be on the exact second. I think you are using the Garmin GPS 18x LVC. There was a firmware update which ensured that the serial adta arrived /before/ the /next/ second edge rather than after it. Ensure your firmware is 3.70 or later. See: http://www.satsignal.eu/ntp/Garmin-GSP18x-LVC-firmware-issue.htm I see that 3.80 is now out, but I think I am still on 3.70. Hope that helps Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
folk...@vanheusden.com said:
remote refid st t when poll reach delay offset jitter
==
x127.127.28.0.NMEA. 0 l3 16 3770.000 -994.05 7.857
x127.127.28.1.PPS.0 l7 16 3770.000 -250.13 572.812
+192.168.64.18 .PPS.1 u 66 128 3770.553 -0.055 0.033
*192.168.64.2.PPS.1 u 99 128 3770.237 -0.062 0.039
+192.168.64.168 .PPS.1 u 44 128 3770.646 -0.013 0.321
Something is broken. What NMEA device are you using? Why are you using gpsd
It is a garmin 18x lvc.
rather than ntpd's NMEA driver?
Oh for convenience. I need to patch ntpd to use linux pps (afaik) and on
other systems I successfully run gpsd with ntpd (read: low jitter).
It looks like the NMEA side it is off by a second. Some devices do that.
You can fix that with some fudging.
Yes, I'm not so worried about the nmea part, I might even decide to
remove it from the configuration. What I mean is: if I set the clock to
the current time, than it is only a matter of keeping it at that with
the pps.
The PPS stuff is off by 250 ms. Are you using the wrong edge? (Got a scope
handy?)
Well, the offset is not constant. If you look at
http://keetweej.vanheusden.com/~folkert/nanosg20.png you see it is
between 0 and -1ms. I now notice that it is not random-ish but consists
of a few specific values:
folkert@belle:~$ cat peerstats | grep 127.127.28.1 | awk '{ print $5; }' | cut
-c 1-6 | sort | uniq -c | sort -rn
503 -0.874
497 -0.875
486 -0.999
467 -1.000
365 -0.249
332 -0.250
201 -0.857
188 -0.125
184 -0.142
140 -0.124
131 -0.000
113 0.
108 -0.166
24 -0.833
5 -0.200
2 -0.856
2 -0.799
2 -0.199
1 -0.167
1 -0.143
1 0.0002
1 0.0001
This is with 3754 lines.
If I clean it a little:
1000x -0.8745
953x -0.9995
697x -0.2495
328x -0.1245
and so on.
Folkert van Heusden
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Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
Thanks for your graphs, but what are the Y-axis units! http://keetweej.vanheusden.com/~folkert/nanosg20.png is in ms and not the delay, the offset instead. Inn your billboard above, the PPS looks to be on the wrong edge - perhaps the pulse is 250 ms wide and you are syncing to the trailing edge and not the leading. well the offset is not constant. Now it is even 1 second: remote refid st t when poll reach delay offset jitter == x127.127.28.0.NMEA. 0 l5 16 3770.000 -1002.1 0.096 *127.127.28.1.PPS.0 l9 16 3770.000 -1000.2 394.379 +192.168.64.18 .PPS.1 u 64 64 3770.548 -0.360 3.083 +192.168.64.2.PPS.1 u 108 128 3770.251 -1.128 0.918 -192.168.64.168 .PPS.1 u 34 64 3771.153 -0.755 3.958 Can you check that out? I recall that I can but I think (open for telling me I'm wrong) the primary problem is with the offset jumping all over the place: see my mail a couple of minutes ago. it's the positive going transition on the DCD connection which needs to be on the exact second. I think you are using the Garmin GPS 18x LVC. There was a firmware update which ensured that the serial adta arrived /before/ the /next/ second edge rather than after it. Ensure your firmware is 3.70 or later. See: http://www.satsignal.eu/ntp/Garmin-GSP18x-LVC-firmware-issue.htm I see that 3.80 is now out, but I think I am still on 3.70. I'll have a look at it this weekend. Folkert van Heusden -- Multitail es una herramienta flexible que permite visualizar los log file y seguir la ejecución de comandos. Permite filtrar, añadir colores, combinar archivos, la visualización de diferencias (diff- view), etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
The computer itself and the NTP installation are OK because we can see it syncing to other NTP servers. Likely you have a problem in the way the GPS using is connected. Some common errors is an inverted PPS, just flip it ad see if you gets better, it is really hard to see a 1Hz signal on a scope. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
On Wed, Jul 3, 2013 at 4:14 PM, folkert folk...@vanheusden.com wrote: Oh for convenience. I need to patch ntpd to use linux pps (afaik) and on other systems I successfully run gpsd with ntpd (read: low jitter). Using gpsd with ntpd reduces the jitter versus just using ntpd by itself? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
It is a garmin 18x lvc. That's pretty vanilla. It really should work. I won't be surprised if the NMEA is off by hundreds of ms and/or has 100 ms of wander, but the PPS should work. Would you please try ntpd's NMEA driver, preferably from the latest ntp-dev http://support.ntp.org/bin/view/Main/SoftwareDownloads The PPS code used by ntpd is different from gpsd. If that doesn't work we should try to fix it. rather than ntpd's NMEA driver? Oh for convenience. I need to patch ntpd to use linux pps (afaik) and on other systems I successfully run gpsd with ntpd (read: low jitter). Were any of those systems ARM? - One possibility is that the CPU is getting turned off when idle to save power. If that includes the stuff normally used for timekeeping, things could get screwed up when it gets turned back on. It has to reset the time, probably getting it from the RTC. Can you measure the power when idle? (kill off as much as possible, things like ntpd) If that's suspiciously low that might be the problem. Can you keep it busy? If nothing else, while true; do true; done -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20
You could also try questi...@lists.ntp.org. The developers etc hang out on that list. There are a lot of helpful experts on NTP there. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Thursday, 4 July 2013 8:34 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] looking for low-power system for gps ntp timekeeping NANOSG20 It is a garmin 18x lvc. That's pretty vanilla. It really should work. I won't be surprised if the NMEA is off by hundreds of ms and/or has 100 ms of wander, but the PPS should work. Would you please try ntpd's NMEA driver, preferably from the latest ntp-dev http://support.ntp.org/bin/view/Main/SoftwareDownloads The PPS code used by ntpd is different from gpsd. If that doesn't work we should try to fix it. rather than ntpd's NMEA driver? Oh for convenience. I need to patch ntpd to use linux pps (afaik) and on other systems I successfully run gpsd with ntpd (read: low jitter). Were any of those systems ARM? - One possibility is that the CPU is getting turned off when idle to save power. If that includes the stuff normally used for timekeeping, things could get screwed up when it gets turned back on. It has to reset the time, probably getting it from the RTC. Can you measure the power when idle? (kill off as much as possible, things like ntpd) If that's suspiciously low that might be the problem. Can you keep it busy? If nothing else, while true; do true; done -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
What did they leave out of the hardware? Hard to tell what to look for when it's not there. Thanks for sharing your experience. -- eric On Mon, Jul 1, 2013 at 10:43 PM, NeonJohn j...@neon-john.com wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. PSS: I have a couple of Whites, one unopened, and a prototyping board for sale. Cheap :-) John On 07/01/2013 11:14 AM, Chris Albertson wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On 02/07/13 06:43, NeonJohn wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. You are not restricted to just Angstrom. My fleet run Debian. FreeBSD is also available. First thing I do is blow away Angstrom from any SD card. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. Hmm, is this a case of Angstrom being beind the kernel curve, or is it still an issue when running things like Debian ? I've not had the need to use SPI on the BB yet, only the Pi. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. I've only ever had one SD card go dead on me on my entire fleet, and I suspect that was actually my fault, not Debian's :) A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. I've heard he can be somewhat robust to deal with. That said, he is very knowledgeable from what I've seen/understand. Never actually had to mail the mailing list itself though - found all the answers I needed in the archive - often from him! PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. Hmm. I checked a lot of the things I'd need on the black for this type of application, and found they were all still there (Serial Ports, PRUSS, Timers etc). Yes you may need to twiddle the pinmux as by default it goes to he HDMI stuff etc, but they are still there Is there something specific here you are thinking of ? Maybe I just don't need what they left off. I do remember looking and going Meh, not important for what I'm doing Best Regards Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On 07/02/2013 02:11 AM, Eric Williams wrote: What did they leave out of the hardware? Hard to tell what to look for when it's not there. Thanks for sharing your experience. I'm not sure what all is gone other than the USB port since I haven't bought one. There is a list of omissions in the mailing list archive, though. One other thing I forgot to mention. There is no voltage regulation or over-voltage protection on the board. The 5.0 volt input goes directly to the TI power management chip. My white BB would not boot on 5.1 volts. It required exactly 5.0 volts. I ended up taking a 9 volt wall wart and hacking an LM7805 voltage regulator into the positive lead. I did not test it for under-voltage but I imagine it's just as sensitive in that direction. John -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On 07/02/2013 02:14 AM, Iain Young wrote: On 02/07/13 06:43, NeonJohn wrote: Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. You are not restricted to just Angstrom. My fleet run Debian. FreeBSD is also available. First thing I do is blow away Angstrom from any SD card. Yeah, and so is Ubuntu. So if you want to become a Linux (kernel) hacker instead of concentrating on your application, a BB is just for you. OTOH, if you expect it to just work out of the box like the Arduino and many other boards do, you'll be sorely disappointed. One other thing I forgot to mention. BeagleBoard actively discourages volume purchases and commercial use. Circuitco, the company that actually makes the BB will sell into commercial applications but at a considerably higher price. Finally https://www.gumstix.com/ offers a BB white clone with commercially rated parts for about $100. Supposedly their Linux implementation is much better supported, though I have no personal experience. One positive thing is that TI offers something called StarterWare for people who don't want to bother with an OS. It abstracts much of the intricacies of the bare metal. I downloaded a copy and took a look and was fairly impressed but by then I knew that a commercial grade board was going to cost in the $100 range so I had already abandoned the product. John -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Le 2 juil. 2013 à 02:52, Bob Camp a écrit : Hi snip The reference I was making was to a pie in the sky 1.8 GHz clocked timer integrated into a CPU chip. That would let you come up with ~ 600 ps timing directly. Since it would be both unusual and very fast, a driver (potentially tightly linked to the kernel) would be needed. That's not a trivial thing…. Is that what you really want? In most modern x86 CPU's you have a TSC which is a 64bit counter incremented at the cpu clock cycle speed . You can capture that with a single instruction. NTP uses that if it is available. So to get an accurate TI you just take 2 samples and subtract. You just need to take into account interrupt handling latency. I don't think this is available in ARM under that name, but there is a cycle count register CCNT which does the same thing. I think it is 64 bit as well. Mike -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
mc235...@gmail.com said: Is that what you really want? In most modern x86 CPU's you have a TSC which is a 64bit counter incremented at the cpu clock cycle speed . You can capture that with a single instruction. NTP uses that if it is available. So to get an accurate TI you just take 2 samples and subtract. You just need to take into account interrupt handling latency. I don't think this is available in ARM under that name, but there is a cycle count register CCNT which does the same thing. I think it is 64 bit as well. The problem is that there is a lot of noise in the interrupt handling. It's things like cache faults. At the 10s of microsecond level, it probably doesn't matter much. Below that, things get interesting. SOC type chips (mostly ARM) usually have some sort of counter/timer gizmo with a register that gets loaded (before any interrupt) when an external signal changes. That change can also generate an interrupt and the interrupt handler can read the register. It works great for PPS type stuff. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi The issue there is the clock on the external inputs. The interupts can't directly hit the TSC. They only get into the device after being clocked by a much slower clock. Bob On Jul 2, 2013, at 3:32 AM, mike cook mc235...@gmail.com wrote: Le 2 juil. 2013 à 02:52, Bob Camp a écrit : Hi snip The reference I was making was to a pie in the sky 1.8 GHz clocked timer integrated into a CPU chip. That would let you come up with ~ 600 ps timing directly. Since it would be both unusual and very fast, a driver (potentially tightly linked to the kernel) would be needed. That's not a trivial thing…. Is that what you really want? In most modern x86 CPU's you have a TSC which is a 64bit counter incremented at the cpu clock cycle speed . You can capture that with a single instruction. NTP uses that if it is available. So to get an accurate TI you just take 2 samples and subtract. You just need to take into account interrupt handling latency. I don't think this is available in ARM under that name, but there is a cycle count register CCNT which does the same thing. I think it is 64 bit as well. Mike -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. I've only ever had one SD card go dead on me on my entire fleet, and I suspect that was actually my fault, not Debian's :) Recent Linux kernels (3.8) have a new filesystem called 'f2fs'. This is a logging filesystem: it appends data instead of overwriting (and does a flush if the fs gets full). This should increase the lifespan. I have a couple (6) of raspberry pi's (pies?) using this filesystem and indeed it seems to help. Folkert van Heusden -- Multitail est un outil permettant la visualisation de fichiers de journalisation et/ou le suivi de l'exécution de commandes. Filtrage, mise en couleur de mot-clé, fusions, visualisation de différences (diff-view), etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
The way to run an embedded Linux system is NOT to run off the SD card. Set up a small RAM disk and write to the disk image. I think you could get this to work but you have to know a little about unix-like OSes so you can make changes. That is one reason I suggested the Item Atom. It is a standard PC motherboard and can run the more common un-modified version of any OS you like. I boot them off the network or from a a USB flash drive and then un-mound the boot drive. A boot drive should be read-only and never written to. On Mon, Jul 1, 2013 at 10:43 PM, NeonJohn j...@neon-john.com wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. PSS: I have a couple of Whites, one unopened, and a prototyping board for sale. Cheap :-) John On 07/01/2013 11:14 AM, Chris Albertson wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On Tue, Jul 2, 2013 at 12:32 AM, mike cook mc235...@gmail.com wrote: ... In most modern x86 CPU's you have a TSC which is a 64bit counter incremented at the cpu clock cycle speed . You can capture that with a single instruction. NTP uses that if it is available. So to get an accurate TI you just take 2 samples and subtract. You just need to take into account interrupt handling latency. I don't think this is available in ARM under that name, but there is a cycle count register CCNT which does the same thing. I think it is 64 bit as well. It is a nanosecond counter that runs off the system clock. However the tick normally is more then a few nanoseconds and from what I've seen is microseconds. I have looked at many samples over hours long periods and they were all even used apart. That said, for NTP it is more than good enough or shout I say at least 10X better than required. For a hobby type problem where the goal is just to see how well you can do even if there is no need then I think yo want a hardware implementation. Run a counter at 1GHz and have the leding edge of the PPS sample the counter. Net you need to modify the OS to use this counter for timing. You could build this or, there are some CPUs that have this already implemented. But in any case sampleing the Intel timer gets you to a few Usec and is more then enough for NTP. The leak like is the Ethernet connections which gives millisecond level performance no matter how good the server is. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
John, The SD Card issue is serious but not unique go the BBB. I believe there are ways to configure any Linux distro to make the SD card read only, at the cost of losing logging and data every time you power off. Alternately, one could partition the SD card with a second partition just for data you want to save. If you Google for Flash and Linux, you will get lots of suggestions for things to do. Didier KO4BB NeonJohn j...@neon-john.com wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. PSS: I have a couple of Whites, one unopened, and a prototyping board for sale. Cheap :-) John On 07/01/2013 11:14 AM, Chris Albertson wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
How do folks think that the Odroid/U2 might compare? http://www.hardkernel.com/renewal_2011/products/prdt_info.php More expensive than Raspberry Pi or BeagleBone black, but higher performance? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi Is there a serial port on that board? NTP with USB serial is a bit clunky. Bob On Jul 1, 2013, at 6:57 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: How do folks think that the Odroid/U2 might compare? http://www.hardkernel.com/renewal_2011/products/prdt_info.php More expensive than Raspberry Pi or BeagleBone black, but higher performance? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi Is there a serial port on that board? NTP with USB serial is a bit clunky. Bob === Good point! I don't see one on that board, but the X2 has GPIO ports. Getting more expensive again, though http://www.hardkernel.com/renewal_2011/products/prdt_info.php?g_code=G135235611947tab_idx=2 David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi For a lot of what we do, having a board with 16 GPIO's and a couple of UART's pinned out is probably more important than 1.2 vs 1.7 GHz on the CPU(s). A lot of the Korean and Chinese boards seem to be aimed at driving a TV for streaming video. All the other stuff is probably still there. Getting at it on the bottom of a BGA - not so easy. The i/o connector on the Pi has it's issues, but at least it's there. Of course for timing applications, having a couple of timers and some high speed capture pins is the ultimate goal. Externally accessible =32 bit timers driven off a 1 GHz clock would also be nice. I suspect all that's going to be a bit hard to find in a cheap generic board. Since all of these boards run a fairly complex OS, we'd also need kernel code to support them ... Bob On Jul 1, 2013, at 8:58 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Hi Is there a serial port on that board? NTP with USB serial is a bit clunky. Bob === Good point! I don't see one on that board, but the X2 has GPIO ports. Getting more expensive again, though http://www.hardkernel.com/renewal_2011/products/prdt_info.php?g_code=G135235611947tab_idx=2 David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
For a few dollars LESS you can get an Intel dual-core Atom board. It is a standard PC motherboard. These can run a file server, a web server, SSH and NTP all at the same time and have about 90% idle time on the CPU. (Running those other processes does not effect NTP.) Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboardhttp://www.amazon.com/Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard/dp/B007BHTMX6/ref=sr_1_5?ie=UTF8qid=1372689454sr=8-5keywords=intel+atom Those tiny Arm boards are best until the price gets about about $45. Above that I think they are not a great value. On Mon, Jul 1, 2013 at 3:57 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: How do folks think that the Odroid/U2 might compare? http://www.hardkernel.com/**renewal_2011/products/prdt_**info.phphttp://www.hardkernel.com/renewal_2011/products/prdt_info.php More expensive than Raspberry Pi or BeagleBone black, but higher performance? __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Yes but how much power do they use? These arm boardjes are 5 watt, some even 1 watt. On Mon, Jul 01, 2013 at 07:43:49AM -0700, Chris Albertson wrote: For a few dollars LESS you can get an Intel dual-core Atom board. It is a standard PC motherboard. These can run a file server, a web server, SSH and NTP all at the same time and have about 90% idle time on the CPU. (Running those other processes does not effect NTP.) Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboardhttp://www.amazon.com/Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard/dp/B007BHTMX6/ref=sr_1_5?ie=UTF8qid=1372689454sr=8-5keywords=intel+atom Those tiny Arm boards are best until the price gets about about $45. Above that I think they are not a great value. On Mon, Jul 1, 2013 at 3:57 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: How do folks think that the Odroid/U2 might compare? http://www.hardkernel.com/**renewal_2011/products/prdt_**info.phphttp://www.hardkernel.com/renewal_2011/products/prdt_info.php More expensive than Raspberry Pi or BeagleBone black, but higher performance? __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Folkert van Heusden -- Always wondered what the latency of your webserver is? Or how much more latency you get when you go through a proxy server/tor? The numbers tell the tale and with HTTPing you know them! http://www.vanheusden.com/httping/ --- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
For a NTP use the $40 ARM. The Atom is going to pull maybe 10W of power but can do a lot more. I just did not see the use of the $90 quad core ARM. It is over kill for NTP I had my Atom running NTP, file server and inside a VMware virtual machine Lady Heather to monitor the Thunderbolt GPS. The Atom was headless so the LH display screen was exported to one of the other computers when needed. Related Topic: It would be great to run LH on an ARM and not need to have to keep a PC running, even if the PC is an Atom running a virtual PC. On Mon, Jul 1, 2013 at 7:47 AM, folkert folk...@vanheusden.com wrote: Yes but how much power do they use? These arm boardjes are 5 watt, some even 1 watt. On Mon, Jul 01, 2013 at 07:43:49AM -0700, Chris Albertson wrote: For a few dollars LESS you can get an Intel dual-core Atom board. It is a standard PC motherboard. These can run a file server, a web server, SSH and NTP all at the same time and have about 90% idle time on the CPU. (Running those other processes does not effect NTP.) Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard http://www.amazon.com/Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard/dp/B007BHTMX6/ref=sr_1_5?ie=UTF8qid=1372689454sr=8-5keywords=intel+atom Those tiny Arm boards are best until the price gets about about $45. Above that I think they are not a great value. On Mon, Jul 1, 2013 at 3:57 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: How do folks think that the Odroid/U2 might compare? http://www.hardkernel.com/**renewal_2011/products/prdt_**info.php http://www.hardkernel.com/renewal_2011/products/prdt_info.php More expensive than Raspberry Pi or BeagleBone black, but higher performance? __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nuts https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Folkert van Heusden -- Always wondered what the latency of your webserver is? Or how much more latency you get when you go through a proxy server/tor? The numbers tell the tale and with HTTPing you know them! http://www.vanheusden.com/httping/ --- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Thanks. I didn't know there were two kinds. This is more useful for only $5 more. Loots like a good platform for porting Lady Heather. Any interest in that. My idea is to have a web based GUI so you don't need a display or keyboard. The ARM (or whatever) runs both NTP and LH and shares a power supply with the Thunderbolt. On Sun, Jun 30, 2013 at 9:47 PM, Paul tic-...@bodosom.net wrote: Chris Albertson albertson.chris at gmail.com Sun Jun 30 23:12:23 EDT 2013 So yu are getting the Beaglebone Black for about $45. Do you have a link to a supplier. The Beagle Bone Black is about half the cost of the Beagle Bone (White) and the pricing is reasonably consistent across vendors. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On Mon, Jul 1, 2013 at 1:31 AM, David J Taylor wrote: There is one write-up here: ... for using the BeagleBone Black as an NTP server, but he seems to have an offset of -0.281 ms from his PPS source, which is rather high. It happens. Particularly if the discipline is botched for some reason. The jitter is low so that's a good sign. However I think he's using a BeagleBoard not a BeagleBone of either flavor, certainly not a Black since the ntpq output is reported as a year ago -- not that that should really matter for a simple PPS clock. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Bob Camp li...@rtty.us said: Since all of these boards run a fairly complex OS, we'd also need kernel code to support them ... Most OSes already have support for PPS capture on modem control pins so it shouldn't be too hard to add support for GPIO pins. (I'm not claiming it would be trivial, just a lot simpler than starting from scratch.) -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Although quite a bit OT, i would like to coment a bit on the topic of application processor boards, as there seem to be a lot of handwaving in this area. On Mon, 1 Jul 2013 08:14:55 -0700 Chris Albertson albertson.ch...@gmail.com wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. There are actually 4 kinds of the beagle family: Beagle Board Beagle Board xM Beagle Bone (White) Beagle Bone Black The Board and Board xM are more of the let's replace a PC kind of design, while the two Bone variants are more experimenter, development boards, similar to the idea of arduino. A word on the different boards there are out there: Please keep in mind that most of these boards are using CPUs designed for other uses than most people will use them for. the Beagle Board and the Beagle Bone White use processers that orignally come from wireless (aka cell phone and similar stuff) business. While the xM and the Black use one from the industrial division. You can see that clearly in the features that they support. For comparison, the Raspberry Pi CPU was meant for video applications. That's why you have a humongus GPU whith a tiny CPU attached to it. The CPU was not meant to run an OS, but to support the GPU. Hence the weird USB design, where the USB controller generates interrupts every start of frame (aka every 125us) and the CPU has to do every low level stuff USB needs in software, instead of the hardware doing it (i guess it was cheaper to design that way). Which leads to a lot of problems when doing more than just a little bit of communication over USB. It also explains why an ARM9 processor does not have an hardware ethernet MAC. Similar things can be said about boards like the cubieboard, which uses an AllWinner A10, or A20 for the cubie2. These are CPU designed for tablets and settop boxes. Thus each of the design has their own set of advantages, disadvantages and quirks, depending on where the original CPU design came from. Also keep in mind that you will not run the board without software. The quality of the software package and how easy it is to customize is very different for the various boards out there. General rule of thumb: if lots of people are using it, there is a better chance to find good support for it. The Odroid/hardkernel boards are a nice negative example in that regard. Another rule of thumb: being able to compile the whole software package yourself is not just a nice feature, it's a must have. Stay away from any board that needs any binary only stuff or where you cannot compile everything from source. Also, if you don't get full schematics, that should make you suspicious. HTH Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On 7/1/2013 10:47 PM, Attila Kinali wrote: General rule of thumb: if lots of people are using it, there is a better chance to find good support for it. The Odroid/hardkernel boards are a nice negative example in that regard. Attila, could you please comment a bit further on the Odroid board ? I intended to use one for a project, but now you made me rethinking my choice, considered that I am far from being a Linux guru... TNX 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi On Jul 1, 2013, at 4:02 PM, Hal Murray hmur...@megapathdsl.net wrote: Bob Camp li...@rtty.us said: Since all of these boards run a fairly complex OS, we'd also need kernel code to support them ... Most OSes already have support for PPS capture on modem control pins so it shouldn't be too hard to add support for GPIO pins. (I'm not claiming it would be trivial, just a lot simpler than starting from scratch.) The reference I was making was to a pie in the sky 1.8 GHz clocked timer integrated into a CPU chip. That would let you come up with ~ 600 ps timing directly. Since it would be both unusual and very fast, a driver (potentially tightly linked to the kernel) would be needed. That's not a trivial thing…. Bob -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
I did a quick test using a modified Python script to measure the elapsed time of several NTP round trips http://code.activestate.com/recipes/117211-simple-very-sntp-client/ The script is run on the Atom machine, all of the servers are running ntpd 4.2.6p5 1.6 GHz Atom, loopback: 8100 req/s 400 MHz MIPS, no FPU (TL-WR703N): 2500 req/s 720 MHz ARM (Beaglebone): 3800 req/s The R-Pi and the B-Bone should handle hundreds - thousands of behaving clients. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. PSS: I have a couple of Whites, one unopened, and a prototyping board for sale. Cheap :-) John On 07/01/2013 11:14 AM, Chris Albertson wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On Fri, 28 Jun 2013 11:28:44 +0200 folkert folk...@vanheusden.com wrote: It must be a system 5 watt, so probably an ARM system. It will only run ntpd so not much ram is required. It will have 10 (ntp-)clients so a very powerfull processor is not required. Get a board with a modern uC that has an ethernet interface and 32bit capture/compare unit, and a cheap, low power gps module and you get to 1W including all losses. eg: https://www.olimex.com/Products/ARM/ST/STM32-E407/ plus http://www.ebay.com/itm/Ublox-NEO-6M-GPS-Module-w-Antenna-For-Arduino-MWC-IMU-Multi-Rabbit-Flight-A100-/261165592580 As OS i would suggest using nuttx or similar to get all the ground work. I've also seen some uC ntp implementations, but i cannot find them currently. Oh.. and if you want to go the linux way and use a Raspberry Pi.. just dont! Use a Beaglebone black instead. It uses less power and is easier to deal with. Not to mention that you dont have all those USB related problems. There has been some discussion about using the BBB as an NTP server in the past weeks on this list. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
From: Attila Kinali [] Oh.. and if you want to go the linux way and use a Raspberry Pi.. just dont! Use a Beaglebone black instead. It uses less power and is easier to deal with. Not to mention that you dont have all those USB related problems. [] Attila Kinali === I've built three Raspberry Pi stratum-1 NTP servers: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html one of which has both a Wi-Fi dongle and a DVB TV receiver stick attached, and on none of these have I seen any USB problems. I'm using a 5.25 V 2A power supply from ModMyPi.com. You can view the timekeeping accuracy here: http://www.satsignal.eu/mrtg/performance_ntp.php Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
david-tay...@blueyonder.co.uk said: I've built three Raspberry Pi stratum-1 NTP servers: ... and on none of these have I seen any USB problems ... As I understand it, the problem with USB on the Raspberry Pi is that the new/second version left out the current limiting on the power to the USB connectors. So when you plug in a device, there will be a glitch on the 5V power rail as the empty filter caps get charged up. So if you don't plug things in, it should work OK. You might also get lucky if the caps on your devices are small or you have long USB cables or you have a solid power supply for your Raspberry Pi or ... -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
From: Hal Murray [] As I understand it, the problem with USB on the Raspberry Pi is that the new/second version left out the current limiting on the power to the USB connectors. So when you plug in a device, there will be a glitch on the 5V power rail as the empty filter caps get charged up. So if you don't plug things in, it should work OK. You might also get lucky if the caps on your devices are small or you have long USB cables or you have a solid power supply for your Raspberry Pi or ... === I've heard that as well. The majority of my own usage has been with devices which are permanently attached, although the Wi-Fi dongle and TV receiver dongle I mentioned have been unplugged and re-plugged without issue. My PSU is well over the minimum spec. I wouldn't expect an NTP server to be having devices continually added and removed, either Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
On 30 Jun, 2013, at 08:50 , David J Taylor david-tay...@blueyonder.co.uk wrote: From: Attila Kinali [] Oh.. and if you want to go the linux way and use a Raspberry Pi.. just dont! Use a Beaglebone black instead. It uses less power and is easier to deal with. Not to mention that you dont have all those USB related problems. [] Attila Kinali === I've built three Raspberry Pi stratum-1 NTP servers: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html one of which has both a Wi-Fi dongle and a DVB TV receiver stick attached, and on none of these have I seen any USB problems. I'm using a 5.25 V 2A power supply from ModMyPi.com. You can view the timekeeping accuracy here: http://www.satsignal.eu/mrtg/performance_ntp.php You aren't necessarily showing the part where the Raspberry Pi is a bit weak, though. How well do clients which receive their time via the USB ethernet interface do? The Beaglebone Black has about three advantages going for it in this application: - The ARM CPU is about twice as fast as the Raspberry Pi's for about the same power consumption (I'm not sure this is a particular advantage for NTP, however, so I won't count it). - The Ethernet MAC core is built into the SOIC, and tightly coupled to it, so packet traffic doesn't have to sit waiting for the USB scheduler to get around to doing something with it. - The Ethernet MAC core also provides fairly good, complete IEEE1588 support. This is not of direct use to NTP but does provide a way to calibrate the software timestamps which NTP produces and consumes to better match when the packets arrive from and are transmitted by the actual hardware. I.e. you can measure the typical difference between hardware and software inbound timestamps (measuring interrupt latency), and hardware and software outbound timestamps (measuring the processing time spent in the outbound network stack) for PTP UDP packets, and then use these results to improve the symmetry of software timestamps for NTP UDP packets. There is no way I know of to measure this without the IEEE 1588 support (and the outbound number in particular is often big enough to deserve correction). - The TI SOIC also has a hardware timestamp capture peripheral (look for eCap in the documentation) which can capture PPS edge times with single-digit-nanosecond accuracy. That's a couple of orders of magnitude better than interrupt sampling and eliminates the jitter of the latter measurements. For a $5-$10 difference in price for the board I think these are worth it. The RPI makes a fine, low-power replacement for Intel hardware for this, but the Beaglebone Black has the raw material to do significantly better at this than either of them. The only problem with the Beaglebone is that it is not as popular as the Raspberry Pi, so making use of the former is going to require one to do more work on one's own to take advantage of it. Dennis Ferguson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
So yu are getting the Beaglebone Black for about $45. Do you have a link to a supplier. I thought they were at least twice that price. On Sun, Jun 30, 2013 at 1:43 PM, Dennis Ferguson dennis.c.fergu...@gmail.com wrote: For a $5-$10 difference in price for the board I think these are worth it. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] looking for low-power system for gps ntp timekeeping
Chris Albertson albertson.chris at gmail.com Sun Jun 30 23:12:23 EDT 2013 So yu are getting the Beaglebone Black for about $45. Do you have a link to a supplier. The Beagle Bone Black is about half the cost of the Beagle Bone (White) and the pricing is reasonably consistent across vendors. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
From: Dennis Ferguson [] You aren't necessarily showing the part where the Raspberry Pi is a bit weak, though. How well do clients which receive their time via the USB ethernet interface do? The Beaglebone Black has about three advantages going for it in this application: [] For a $5-$10 difference in price for the board I think these are worth it. The RPI makes a fine, low-power replacement for Intel hardware for this, but the Beaglebone Black has the raw material to do significantly better at this than either of them. The only problem with the Beaglebone is that it is not as popular as the Raspberry Pi, so making use of the former is going to require one to do more work on one's own to take advantage of it. Dennis Ferguson == Dennis, I've tested with 75 clients (simulated load) and not seen any problems with the Raspberry Pi's own time keeping. I'll set my FreeBSD PC to look at the the three Raspberry Pi cards and report back A first report is that the offset is shown as 0.091 ms from one RPi and 0.065 ms from the second, and 0.056 ms on the third RPi which is operating over Wi-Fi. This is far better than I see from any Internet servers on my Cable Modem ISP service. Jitter is 0.022 and 0.027 ms for the LAN connected devices, again much better than the best Internet device which shows 0.110 ms (at what is the middle of the night for many - 06:00 clock time here). Here the two units are similarly priced, so you can take your choice. There is one write-up here: https://groups.google.com/forum/#!topic/beagleboard/bU_xZ9tWoiA for using the BeagleBone Black as an NTP server, but he seems to have an offset of -0.281 ms from his PPS source, which is rather high. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi Low power and system load are both worth putting some dimensions on. A very simple system may be ok with a single client running into it and nothing else going on. A system that will handle 500 hits a second is something altogether different. Low power could be 100 watts, it also could be 100 milliwatts. There will be a power / load tradeoff …. Since you already seem to have a bit of this and a bit of that (high power server, low power Pi) it is worth considering exactly where you are going with this new build. Bob == Bob, The maximum test rate I could produce was 75 packets/second, and the Raspberry Pi handled that without any problem. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Well I have the garmins already laying around and I would like to give 'm good use. Folkert van Heusden OK, Folkert, but a handful of resistors would easily convert the levels to the Raspberry Pi, so you could add a couple of stratum-1 servers that way. Alternatively, any of your existing FreeBSD, Linux or Windows PCs which have a serial port (or COM port header on the motherboard) could become new stratum-1 servers - there is no need to buy anything extra. David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
I think the problem is that if you are not clear about what your big picture goal is then yu only get a bunch od not so helpful comments like use this is worked for me.. So what exactly do you want. Are you looking for a very low power, say under 5W server. Something that is very easy to set up and maintain. You have two GPSes, will both go on the same NTP server or do you wnt to set up two NTP servers It must be a system 5 watt, so probably an ARM system. It will only run ntpd so not much ram is required. It will have 10 (ntp-)clients so a very powerfull processor is not required. Folkert van Heusden -- -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] looking for low-power system for gps ntp timekeeping
folkert folkert at vanheusden.com Fri Jun 28 05:28:44 EDT 2013 It must be a system 5 watt, so probably an ARM system. It will only run ntpd so not much ram is required. It will have 10 (ntp-)clients so a very powerfull processor is not required. While not exactly matching your original request I'd get a Laureline from Partially Stapled, a level shifter from any number of places, a power supply, a case and the misc. bits of glue hardware you'd need. Sadly I have no idea when the new Laurelines will be available and what the configurations might be since he's stated a desire to include an optional ublox part on the board. It will do only one thing -- NTP -- with a ~ 1 watt budget. It's open hardware (Cortex microcontroller based) so you could build the previous (current) model but that would require messing with resistors. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
OK, good specs.The The Raspberry Pi should work. They cost about $40 each. The Atom is about $100 and has just over your 5 watt limit but is very much easier to set up, becuase it is just a standard PC and can run a normal version of Linux or BSD Unix. I'd go with a Pi for NTP but if you need any other kind of server, perhaps a NAS for backups then go with Atom and it can run multiple services and still keep very good time.I had one doing this until recently when the mainboard failed after years of running 24x7 It must be a system 5 watt, so probably an ARM system. It will only run ntpd so not much ram is required. It will have 10 (ntp-)clients so a very powerfull processor is not required. Folkert van Heusden -- -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
From: Paul While not exactly matching your original request I'd get a Laureline from Partially Stapled, a level shifter from any number of places, a power supply, a case and the misc. bits of glue hardware you'd need. Sadly I have no idea when the new Laurelines will be available and what the configurations might be since he's stated a desire to include an optional ublox part on the board. [] === Paul, I would have got one of those, except that it (as I understand it) doesn't support any of the NTP management functions such as ntpq -p or ntpq -c rv from remote nodes, nor does it run MRTG. Not being able to monitor remotely was a show-stopper for me. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
David J Taylor Fri Jun 28 12:56:57 EDT 2013 I would have got one of those, except that it (as I understand it) doesn't support any of the NTP management functions such as ntpq -p or ntpq -c rv I was being a bit lazy. It doesn't run NTP. It emits NTP compatible timestamps in response to queries. No NTP means no NTP management functions. Using one as your only clock is unwise but that's true of any clock. As part of a group you monitor it indirectly via peerstats or ntpq/dc from a peer. I believe Michael will be adding support for multiple gps messages (it currently only supports a single output message e.g. zda) which would all be cloned to the monitor port so you could directly observe the state of the receiver. As I tend my flock of clocks the current lack of ntp management support on one is the least of my worries. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] looking for low-power system for gps ntp timekeeping
Hi, I own a couple of GPS modules (garmin 18(x) lvc) which I would like to use as a time-source. Now my server already has such a module connected (via gpsd and a pci rs232 interface) and my raspberry pies too (adafruit modules) so I'm looking for a low-power computer with a complete RS232 connector (DB9) with all signals attached so that I can feed it a PPS. Also real RS232 so that I don't have to mess with resistors and such. I'm considering either this one: http://www.antratek.com/nanosg20-with-128-mb-sdram-and-512-mb-flash or this one: http://www.antratek.com/ontwikkelboard-met-cirrus-logic-ep9302 What do you guys think: would they be any good for timekeeping? Known issues? Regards, Folkert van Heusden -- -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi, I own a couple of GPS modules (garmin 18(x) lvc) which I would like to use as a time-source. Now my server already has such a module connected (via gpsd and a pci rs232 interface) and my raspberry pies too (adafruit modules) so I'm looking for a low-power computer with a complete RS232 connector (DB9) with all signals attached so that I can feed it a PPS. Also real RS232 so that I don't have to mess with resistors and such. I'm considering either this one: http://www.antratek.com/nanosg20-with-128-mb-sdram-and-512-mb-flash or this one: http://www.antratek.com/ontwikkelboard-met-cirrus-logic-ep9302 What do you guys think: would they be any good for timekeeping? Known issues? Regards, Folkert van Heusden === Folkert, As you already know, your Raspberry Pi with the Adafruit module alone would make an excellent NTP server. About 4 watts power consumption, and lower cost than those you list. http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#adafruit What else do you need? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
For less money you could buy an Intel Atom board and it will run Linux and can even act as a small file server. The Intel board is a real Intel 64-bit CPU and it uses VERY little power, notice there is no fan on the heat sink and it fits inside any standard PC chassis. It has a real serial port and you can add up to about 4GB of RAM. But for this use buy a 2GB stick and boot from a small CF card, not disk. Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard/dp/B007BHTMX6http://www.amazon.com/Intel-BOXD2500HN-Dual-Core-Mini-ITX-Motherboard/dp/B007BHTMX6 On Thu, Jun 27, 2013 at 10:43 AM, folkert folk...@vanheusden.com wrote: Hi, I own a couple of GPS modules (garmin 18(x) lvc) which I would like to use as a time-source. Now my server already has such a module connected (via gpsd and a pci rs232 interface) and my raspberry pies too (adafruit modules) so I'm looking for a low-power computer with a complete RS232 connector (DB9) with all signals attached so that I can feed it a PPS. Also real RS232 so that I don't have to mess with resistors and such. I'm considering either this one: http://www.antratek.com/nanosg20-with-128-mb-sdram-and-512-mb-flash or this one: http://www.antratek.com/ontwikkelboard-met-cirrus-logic-ep9302 What do you guys think: would they be any good for timekeeping? Known issues? Regards, Folkert van Heusden -- -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
As you already know, your Raspberry Pi with the Adafruit module alone would make an excellent NTP server. About 4 watts power consumption, and lower cost than those you list. http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#adafruit What else do you need? Well I have the garmins already laying around and I would like to give 'm good use. Folkert van Heusden -- www.TrustedTimestamping.com is a service that enables you to show that at a certain point in time, you had access to a hash-value reflecting the contents of a file (this file can be a word document, a jpeg image, everything). -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
folk...@vanheusden.com said: I own a couple of GPS modules (garmin 18(x) lvc) which I would like to use as a time-source. Now my server already has such a module connected (via gpsd and a pci rs232 interface) and my raspberry pies too (adafruit modules) so I'm looking for a low-power computer with a complete RS232 connector (DB9) with all signals attached so that I can feed it a PPS. Also real RS232 so that I don't have to mess with resistors and such. I'm not sure what you mean by resistors and such. At a minimum, you will have to do some wiring to provide power. I'm considering either this one: http://www.antratek.com/nanosg20-with-128-mb-sdram-and-512-mb-flash or this one: http://www.antratek.com/ontwikkelboard-met-cirrus-logic-ep9302 What do you guys think: would they be any good for timekeeping? Known issues? Both web sites have schematics. On the Olimex board, there is nothing connected to the PPS input pin. It is a dev board, so it should be easy to connect up power and PPS. On the Ledato board, there are level shifters on all the signal pins. One of the connectors has a slot for a resistor to supply power on RI. I think there are 2 basic approaches. One is to use a board like the above or others that have been discussed here. You will probably have to do some fiddling. They don't have a real disk so you may not want to do a lot of logging. This is the lowest power approach. The other is to use an embedded PC. If you get one with an Atom chip, the power can be pretty low. I have one (with disk) that uses 14 watts. - There are a handful of tangled considerations: Cost of initial gear and cost of power: You can get refurbished PCs for under $200. An embedded type PC with an Atom chip will pay for itself in under a year. How much fiddling do you have to do to the hardware? How much fiddling do you have to do to the software? Using a real PC often simplifies both. If you can find a HOWTO type web page, that may be good enough. PCs use display and keyboard/mouse to get off the ground. Low end boards without a display probably default to using an RS-232 port to get off the ground. Once you get setup, you can probably run both over the Ethernet. Some PCI-RS232 cards have a jumper to supply power on one of the signal pins. They were intended to power things like scanners before USB. (I'll fish out some details if anybody wants them.) You still have to solder the wires from the GPS hockey-puck to a DB-9 connector. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
Hi Low power and system load are both worth putting some dimensions on. A very simple system may be ok with a single client running into it and nothing else going on. A system that will handle 500 hits a second is something altogether different. Low power could be 100 watts, it also could be 100 milliwatts. There will be a power / load tradeoff …. Since you already seem to have a bit of this and a bit of that (high power server, low power Pi) it is worth considering exactly where you are going with this new build. Bob On Jun 27, 2013, at 1:43 PM, folkert folk...@vanheusden.com wrote: Hi, I own a couple of GPS modules (garmin 18(x) lvc) which I would like to use as a time-source. Now my server already has such a module connected (via gpsd and a pci rs232 interface) and my raspberry pies too (adafruit modules) so I'm looking for a low-power computer with a complete RS232 connector (DB9) with all signals attached so that I can feed it a PPS. Also real RS232 so that I don't have to mess with resistors and such. I'm considering either this one: http://www.antratek.com/nanosg20-with-128-mb-sdram-and-512-mb-flash or this one: http://www.antratek.com/ontwikkelboard-met-cirrus-logic-ep9302 What do you guys think: would they be any good for timekeeping? Known issues? Regards, Folkert van Heusden -- -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] looking for low-power system for gps ntp timekeeping
I think the problem is that if you are not clear about what your big picture goal is then yu only get a bunch od not so helpful comments like use this is worked for me.. So what exactly do you want. Are you looking for a very low power, say under 5W server. Something that is very easy to set up and maintain. You have two GPSes, will both go on the same NTP server or do you wnt to set up two NTP servers From the looks of it NTP will run on either ARM or Atom. The Atom costs about $100 and ARM can be as low as $40. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
