ESP8266 Community Forum

- Wed Aug 05, 2015 12:30 am #25058 Ah, ok. Then it looks like I misunderstood this forum post.
There's also a few mentions of RTC and such in the documentation on the Wiki. If it is not used in the same way as the name 'RTC' implies, that is a little confusing - they should stop calling it an RTC. Or at least clarify the usage.

So, correct me if I'm wrong: there is not an internal RTC comparable to the DSxxxx ICs, BUT there IS an internal clock that shows time from power-on. I got that.
How accurate is that internal clock? So I can estimate how often to try to update the time via Wifi.
I would like to reduce the external parts count, but I guess I will use a DSxxxx RTC if it comes down to that.

- Wed Aug 05, 2015 8:56 am #25083 You right ! I made a mistake when I've said "ESP8266 doesn't have an internal RTC.".
There is one, although not shown in the datasheet block diagram, and not well details in SDK.
And yes, it is not comparable to DSxxx, in fact some people said "RTC=RealTimeCounter" instead of "Clock".
About accuracy, I don't know yet, I will have to experiment. (and it also depends of your own requirements)

- Wed Aug 19, 2015 11:31 am #26481 100 Milliseconds accuracy would be easy by getting time via NTP.

- Wed Aug 19, 2015 11:55 am #26488 I'm already taking time from a NTP server, but what I mean about accuracy is how much it will drift away, so how long I can wait before doing a second NTP request, maybe 24hours is good enough .
This is mostly related about the crystal quality and accuracy provided in ESPs.
Since, it is not my priority for now, I will investigate later ...