NTPClient.getEpochTime() jumps an hour #52
Description
I am using the NTPClient on a Wemos D1 Mini (ESP8266). On occasion, my code is detecting that the return from NTPClient.update() then NTPClient.getEpochTime() has jumped an hour.
I have tested with different NTP server pools (time.nist.gov and pool.ntp.org). The occurrence of the jump is not consistent. I've recorded it in teh morning, event, and over night.
I'm looking for debugging suggestions.
I have the following code fragment (with some gorpy calculations removed):
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org", 0, 3600000); // interval is 1 hour
...
timeClient.begin();
...
... define and initialize some globals
...
void clock_loop() {
current_ticks = millis();
if (next_update < current_ticks) {
if (timeClient.update()) {
... save values from previous iteration as last_epoc, last_hour, last_minute
cur_epoch = timeClient.getEpochTime();
... fetch cur_hour and cur_minute and calc next_update
Serial.printf("Clock updated: %02d, %02d (%lu %lu)\n", cur_hour, cur_minute, cur_epoch);
} else {
// we will assume one minute has passed
... compute cur__hour and cur_minute and calc next_update (to be on a minute boundary)
Serial.printf("Clock update failed: %02d:%02d\n", cur_hour, cur_minute);
}
if (ABS(COMBINE(_hours, _minutes) - COMBINE(last_hour, last_minute)) > 2) {
// more than two minutes have elapsed. something went wrong
Serial.printf("Clock jumped: from %02d:%02d to %02d:%02d\n",
last_hour, last_minute, cur_hour, cur_minute);
}
}
}
Here is a snippet of my logging:
lock updated: 07:05 (1533798300 )
Clock updated: 07:06 (1533798360 )
Clock updated: 07:07 (1533798420 )
Clock updated: 07:08 (1533798480 )
Clock updated: 07:09 (1533798540 )
Clock updated: 07:10 (1533798600 )
Clock updated: 06:11 (1533795061 )
Clock jumped: from 07:10 to 06:11
Clock updated: 06:11 (1533795119 )
Clock updated: 06:12 (1533795120 )
Clock updated: 06:13 (1533795180 )
Clock updated: 06:14 (1533795240 )
Clock updated: 06:15 (1533795300 )