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Thread: Teensy 3.2 schematic question

  1. #1
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    Teensy 3.2 schematic question

    This is probably a dumb question... Looking at the Teensy 3.2 schematic here:

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

    I see that a crystal and a 100uf capacitor are kind of greyed out. What does that mean, are these components optional?

  2. #2
    Senior Member brtaylor's Avatar
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    I'm not sure about the cap, but the greyed out crystal is the optional 32.768 kHz crystal you can add to the bottom of the board. See the pinout here:
    https://www.pjrc.com/teensy/pinout.html

  3. #3
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    Quote Originally Posted by brtaylor View Post
    I'm not sure about the cap, but the greyed out crystal is the optional 32.768 kHz crystal you can add to the bottom of the board. See the pinout here:
    https://www.pjrc.com/teensy/pinout.html
    Oh I see, its optional for the RTC. Thanks!

  4. #4
    The details of the greyed out parts are detailed further down on the schematic page. Scroll down and you’ll see:

    A pair of pads are linked to join VUSB to VIN. For applications where external power is needed, these pads may be cut apart to isolate the board's VIN power from VUSB.

    A 32.768 kHz crystal (shown in gray) may be added to support the real time clock feature. A 100 uF capacitor (shown in gray) may be added for USB host applications, where power applied at VUSB or VIN is not capable of supplying inrush current to USB devices.

    Teensy 3.1 added one signal, "DAC/A14", which was not present on Teensy 3.0. The reset signal moved from the right hand side to a test point on the bottom side. Other than this minor change, Teensy 3.0 and 3.1 are exactly the same schematic.

  5. #5
    Senior Member+ MichaelMeissner's Avatar
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    Quote Originally Posted by aFewBits View Post
    T

    Teensy 3.1 added one signal, "DAC/A14", which was not present on Teensy 3.0. The reset signal moved from the right hand side to a test point on the bottom side. Other than this minor change, Teensy 3.0 and 3.1 are exactly the same schematic.[/I]
    Teensy 3.2 changed the voltage regulator compared to the 3.1, and it moved the location of the reset pad underneath the PCB (and maybe D+/D- pads as well).

  6. #6
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    Okay thanks, I'll review the schematics more carefully.

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