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Thread: ESP8266 Module Clock Frequencies

  1. #1
    Join Date
    May 2007
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    Default ESP8266 Module Clock Frequencies

    How accurate the cpu cloc frequency on the various esp8266 modules? Two issues - how accurate are the crystals on the boards, and how is 80 Mhz (or 160 Mhz) derived from the 26 Mhz crystal oscillators? The easiest way that I can see is to divide the 26Mhz by 13 (to reach 2.0 Mhz) and then use a PLL (or moral equivalent) to multiply that frequency by either 40 or 80 to reach 80 or 160 Mhz. I know that this is achievable (Microchip does it with some of their PIC24 and dsPIC33 parts), but I wonder how must jitter there is and how expensive in chip resources (or not). And in any case, 26Mhz seems to me to be an odd choice for a crystal frequency, but maybe they are used in great volume somewhere else.
    Phil

  2. #2
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    Default Re: ESP8266 Module Clock Frequencies

    I can tell you that the clock on the ESP line of products is HORRIBLE as a real time source. I was seeing errors in excess of 1ms per second. If you really want an accurate clock get an I2C based RTC and keep it in sync with NTP.


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