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Thread: Teensy 3.2 using internal RTC adding crystal

  1. #1

    Teensy 3.2 using internal RTC adding crystal

    In the Time library page is mentioned to ad a crystal and a coincell battery to the Teensy 3.2 to use the internal RTC.

    What does “12.5 pF” mean?

    Do I also need to add a capacitor?

    https://www.pjrc.com/teensy/td_libs_Time.html

    Quote :
    “TimeTeensy3 Example Program

    TimeTeensy3 demonstrates synchronizing Time to the Real Time Clock in Teensy 3.0, 3.1, 3.2, 3.5 & 3.6.
    To use the Teensy 3.0, 3.1 & 3.2 RTC, you must add a 32.768 kHz, 12.5 pF crystal to the bottom side of the board.

  2. #2
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    The 12.5pf is a specification of the crystal to buy. You do not have to add 12.5pf capacitor to the Teensy board. Just get the crystal indicated a few words later, solder it to the Teensy, connect a 3v coin cell and you're goo to go.

  3. #3

    answered. Teensy 3.2 using internal RTC adding crystal

    All clear now. Thanks for the info.

    Quote Originally Posted by grease_lighting View Post
    The 12.5pf is a specification of the crystal to buy. You do not have to add 12.5pf capacitor to the Teensy board. Just get the crystal indicated a few words later, solder it to the Teensy, connect a 3v coin cell and you're goo to go.

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