[neonixie-l] Re: Managing RTC when there's GPS time
I use NTP. I pull time from the RTC until I get a a sync from the internet - then I switch to the internet and I update the RTC whenever I get an update from the network. It all uses UTC, which is converted to local time for display. On Wednesday, September 29, 2021 at 2:01:32 PM UTC-4 gregebert wrote: > I'm using network time that my Raspberry Pi re-acquires roughly every 20 > minutes, with a DS3232 for backup when the internet is down. I need to > tweak the software a bit more to automatically update the DS3232; right now > I have to use my debug utility to manually update it. But this does allow > me to see how much long-term drift there is. Here is an actual check from > today: > > INIT: RTC module = 09/29/21 08:52:56 > INFO: NTP sync acquired at 09/29/21 09:52:12 > > It's been about 6 months since I sync'd the time, and this particular > DS3232 RTC has gained 44 seconds. That's about 3PPM, which is pretty close > to the datasheet spec of 2PPM. I have not made any attempt to use the trim > register yet, but now that I have this data I might give that a shot. > > > > > On Wednesday, September 29, 2021 at 9:34:27 AM UTC-7 nixiebunny wrote: > >> My latest scope clock uses a DS3232 RTC chip for general timekeeping. >> This chip only keeps time to the nearest second, as far as the >> user-readable registers are concerned. >> I also have a USB port that can read the time from a GlobalSat GPS puck. >> This reports the time once a second through the Arduino TinyGPS library, >> with the age of the time in milliseconds (typically 250). This should let >> me compensate for the read delay by setting the tick (50/60Hz) counter in >> my local time variables. >> What do any of you time nuts do about displaying the time accurately, and >> making the RTC be reasonably accurate compared to the GPS? >> Do you discipline the RTC with GPS? Do you just ignore the RTC when GPS >> is available? Set the RTC occasionally? >> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/75498a13-76c8-4c08-b7a6-c66e923443dan%40googlegroups.com.
[neonixie-l] Re: Managing RTC when there's GPS time
I'm using network time that my Raspberry Pi re-acquires roughly every 20 minutes, with a DS3232 for backup when the internet is down. I need to tweak the software a bit more to automatically update the DS3232; right now I have to use my debug utility to manually update it. But this does allow me to see how much long-term drift there is. Here is an actual check from today: INIT: RTC module = 09/29/21 08:52:56 INFO: NTP sync acquired at 09/29/21 09:52:12 It's been about 6 months since I sync'd the time, and this particular DS3232 RTC has gained 44 seconds. That's about 3PPM, which is pretty close to the datasheet spec of 2PPM. I have not made any attempt to use the trim register yet, but now that I have this data I might give that a shot. On Wednesday, September 29, 2021 at 9:34:27 AM UTC-7 nixiebunny wrote: > My latest scope clock uses a DS3232 RTC chip for general timekeeping. This > chip only keeps time to the nearest second, as far as the user-readable > registers are concerned. > I also have a USB port that can read the time from a GlobalSat GPS puck. > This reports the time once a second through the Arduino TinyGPS library, > with the age of the time in milliseconds (typically 250). This should let > me compensate for the read delay by setting the tick (50/60Hz) counter in > my local time variables. > What do any of you time nuts do about displaying the time accurately, and > making the RTC be reasonably accurate compared to the GPS? > Do you discipline the RTC with GPS? Do you just ignore the RTC when GPS is > available? Set the RTC occasionally? > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/082b2c9b-854c-4ea2-bab7-0a7227f2b451n%40googlegroups.com.
[neonixie-l] Re: Managing RTC when there's GPS time
My NIXIE clocks have an on-board GPS receiver and I set the DS3232 to generate a 1 PPS output. On power-up I sanity check the internal registers and if it looks good I transfer the date and time to the uP memory. I pre-increment the internal time and at the PPS IRQ I update the display RAM from the internal register. For GPS, I monitor the serial stream until I confirm a good lock and checksums. I then wait 20 seconds with no errors in the stream and then transfer the GPS time to the internal RAM and switch the PPS interrupt from the RTC to GPS. I assume the GPS PPS is good and use my internal counters, monitor the GPS for bad packets only. If there are too many bad packets, I revert to the RTC PPS. When I determine that GPS time is valid, I write the GPS time to the RTC. Also twice a day I update the RTC from the GPS at the GPS PPS (sort of disciplined). -Bill- On Wednesday, September 29, 2021 at 9:34:27 AM UTC-7 nixiebunny wrote: > My latest scope clock uses a DS3232 RTC chip for general timekeeping. This > chip only keeps time to the nearest second, as far as the user-readable > registers are concerned. > I also have a USB port that can read the time from a GlobalSat GPS puck. > This reports the time once a second through the Arduino TinyGPS library, > with the age of the time in milliseconds (typically 250). This should let > me compensate for the read delay by setting the tick (50/60Hz) counter in > my local time variables. > What do any of you time nuts do about displaying the time accurately, and > making the RTC be reasonably accurate compared to the GPS? > Do you discipline the RTC with GPS? Do you just ignore the RTC when GPS is > available? Set the RTC occasionally? > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/47245b8c-2baf-4271-ae33-c494350a4f15n%40googlegroups.com.
[neonixie-l] Re: Nixie (and other old technology) sighting in video
That's an HP 5216A Counter with the upside down B5560 Nixies. I have one, it's a cool piece. On Wednesday, September 29, 2021 at 9:13:04 AM UTC-4 Tomislav Kordaso wrote: > https://www.youtube.com/watch?v=J8hLqpigv1g > Electronic counter by HP at about 9:05 minute mark. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/40cb4c91-eec9-4b05-931b-b6e03b61ca5en%40googlegroups.com.
[neonixie-l] Managing RTC when there's GPS time
My latest scope clock uses a DS3232 RTC chip for general timekeeping. This chip only keeps time to the nearest second, as far as the user-readable registers are concerned. I also have a USB port that can read the time from a GlobalSat GPS puck. This reports the time once a second through the Arduino TinyGPS library, with the age of the time in milliseconds (typically 250). This should let me compensate for the read delay by setting the tick (50/60Hz) counter in my local time variables. What do any of you time nuts do about displaying the time accurately, and making the RTC be reasonably accurate compared to the GPS? Do you discipline the RTC with GPS? Do you just ignore the RTC when GPS is available? Set the RTC occasionally? -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CAPbqtvfSPwVxsSFADbxm%2BNyVgSsk1AY42GgP%3Dmq0uygGJMBqZg%40mail.gmail.com.
