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Servo Headers Help on Prop BOE — Parallax Forums

Servo Headers Help on Prop BOE

RoboTunaRoboTuna Posts: 25
edited 2013-02-13 10:12 in Propeller 1
I am trying to use the servo header to run my three wire GPS all it needs is a I/O pin and 5V and a ground. But when I try and use Pin 18 on the headers I do not get the signal through but when I use Pin 11 it works perfect. Is the header Sig pin just an out so it does not do I/O.

Comments

  • Martin_HMartin_H Posts: 4,051
    edited 2013-02-13 06:06
    RoboTuna wrote: »
    I am trying to use the servo header to run my three wire GPS all it needs is a I/O pin and 5V and a ground. But when I try and use Pin 18 on the headers I do not get the signal through but when I use Pin 11 it works perfect. Is the header Sig pin just an out so it does not do I/O.

    The servo header pins on the PropBOE are 5 volt tolerant, so the 3.9 k Ohm resistor might be attenuating the signal and preventing the propeller chip from sensing it.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-02-13 10:12
    Martin_H wrote: »
    The servo header pins on the PropBOE are 5 volt tolerant, so the 3.9 k Ohm resistor might be attenuating the signal and preventing the propeller chip from sensing it.

    I agree. I've had several 5V devices not able to see 3.3V logic with a series resistor (including servos).
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