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Thread: Teensy 3.0 and PS/2 keyboard voltage

  1. #1

    Teensy 3.0 and PS/2 keyboard voltage


    I want to connect a PS/2 keypad to my teensy 3.0, however the PS/2 keyboards require 5v and as far as my understanding goes Teensy 3.0 is 3.3v.

    Has anybody managed to connect a keyboard and use the PS/2 keyboard library with their Teensy 3.0?



  2. #2
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    PS2 keyboards use open drain signals with pullup resistors. The pullups do inject some current to the Teensy 3.3V pins, but it's will within the 10 ma limit the pins can handle.

  3. #3
    Senior Member
    Join Date
    Sep 2013
    Hamburg, Germany
    The Teensy 3.0 also provides a way to get 5V from USB for the keyboard, see

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