I believe that the NTP time server defaults to a 5 min update, even if one does not include the setSyncInterval() statement.
It would be nice to be able to turn the auto sync update off (eg by setting the value to 0....this is not the case though!!), as it looks like it interferes with other code elements in my program when it spontaneously choses to run.
I have a process that polls several remote nodes and once the data is coming in via listening serial port, it should not be interrupted.
For now, my solution is to set the update to 100000 seconds ie more than 24 hrs, and power on reboot everyday (with a mechanical time switch!!), this way time gets set on power up and is stable enough for my purposes over following 24hrs.
Or is there some way of intercepting the self generated NTP update request and "putting it on hold" until other processes have run to completion?
I see no simple way of preventing the NTP update from running unrestrained.
I am reluctant to mod the NTP timeserver code as I do not fully understand it.
Alternatively, I may have to resort to a web page scrape to get the time.
I have read a lot around the NTP timesserver topics in the forum, but not specifically this. There were a few unexplained s/w crashes mentioned though....
I don't know what you are talking about. What code are you using? I modified the UdpNtpClient example sketch included with the IDE. I don't use a delay call. I use a variant of the blink without delay function for the timing and it works fine.
Which Arduino board are you using ?
Do you use the Time library ?
I hope you use the newer one at : Time Library, Timekeeping and Time/Date Manipulation on Teensy
What do you need timing for, and how accurate ? Do you need absolute timing (like a time stamp with the real clock and date) or only timing short events ?
Thanks Peter_n....I am using a Due, and do have latest version of Time library.
Accuracy is not of great concern as I can call the NTP service in theory as often as needed, likely once or twice a day would suffice.
I need date and time stamp for event logging, resolution to 1 sec is adequate, and 1 sec a day drift would be fine.
Thanks SurferTim... I am using Time_NTP.pde from Time library, it is similar in part to the Udp NTP Client that you refer to.
I see now, upon reading things over again, that the regular call is actually initiated by the setSyncProvider() , and evidently, it will do its thing even without the setSyncInterval() statement, at its default 5 min interval.
So if I leave both these out and call the main NTP procedure directly, when I wish, all should be well.....we'll see.
I shall use TimeAlarms to request an NTP time update and act upon that request when the program activity allows.
Cheers
Okay.
1 second resolution should not be a problem. I have a 1 second timestamp in an Arduino Mega with NTP. But without the Time library (I think, I'm not sure, it's on my other computer).