Re: Replacing LWIP
Posted: Wed Apr 03, 2019 10:56 am
eriksl wrote:My question remains, why would you need microsecond (or even millisecond) precision on an ESP8266? I am quite sure none of the timers of the ESP8266 has the required accuracy to maintain this precision, even only for a few minutes (microseconds). I've found the RTC to be off several minutes within just 24 hours and that's supposed to be the accurate one (as opposed to the internal timers).
The RTC timing is not based on the crystal. I'm sure that it is just a capacitive based oscillator. From what I remember (might be wrong) the RTC section can use a 32kHz crystal but it isn't included in any of the designs. ESP32 boards have included a 32kHz crystal, with a loss of IO pins.
When running (not sleep) the timing in the ESP8266 has to be accurate. And the specifications on the crystal used with the chip are very tight.
As far as why anyone would need microsecond resolution? It really depends on what they are doing. If they were trying to make a mesh network and needed to measure the best route (least hops) then maybe it would be important.
I have not read the previous posts to this thread, so I am sure I am missing relative points.