Jeffry, Yes, the sync once per day is due to the Arduino software. The ES100 needs to be told when to start receiving the WWVB signal and when to go to sleep. You can modify the software to change the time and number of syncs per day. I would suggest you change it to 2am CA time. The daily sync is used to update the RTC (DS3231) that is on the board. The clock gets the time from the DS3231. I really try to avoid Arduino code so I can't tell you where the code needs to be modified. The 8pm you see corresponds to midnight UTC. Since DST started today your clock should update around 7pm tonight depending on WWVB signal strength at your location.
The sync will happen each time the module is powered up. It usually takes about 3 minutes at my location in Phoenix. In the Arduino .ino file the interrupt count is updated every time the ES100 generates an interrupt. The interrupt code also makes an adjustment to the milliseconds variable value. There is a millis() function somewhere that updates the milliseconds value. I have looked and can't find that function in any of the code supplied with the kit. It may be in the Time library but I haven't looked there. The milliseconds value is used to calculate the time when a valid data string is received from the ES100. There is a note in the ES100.h file that says this: "// This hold the millis() when the interrupt occured, will be useful in the user code to handle the second boundary. New valid data should be handled within 65536 milli seconds, after that the variable will overflow and the user won't be able to calculate the right second boundary." Daylight savings time started at 2 AM this morning. The "NDST 11/07 02:00" means daylight savings time ends at 2am on 11/07, first Sunday in November. "(N)o (D)aylight (S)avings (T)ime". Ray, AB7HE -------- Original Message -------- Subject: [time-nuts] Re: NIST 60KHz message From: Jeffrey Pawlan <paw...@runbox.com> Date: Sun, March 14, 2021 7:52 am To: time-nuts@lists.febo.com I have been using the new BPSK receiver for NIST. There are two strange things that perhaps others can explain. It only syncs one and only one time per day, usually around 8pm. It also shows an interrupt count anywhere between 2 and 50 every day. I am sure it can receive the signal more frequently than once in a day. Is that caused by the design of the arduino software? I also saw last night they sent a message "DST starts at 11/07 0200". This morning it says "DST in effect" and "NDST at 11/07". Why are they showing that date? Regards, Jeffrey Pawlan WA6KBL _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.