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Pullups on endstop pins

shaissshaiss
edited November 2016 in Questions & Answers
I'm a bit confused on the pullups on endstop pins.  I'm trying out the dev FW so I can use a microswitch to detect out of filament.  The filament passes over the switch and when there's no filament, the switch releases therefore the signal goes low or off.

In the fw I've enabled the pullup resistor since that's whats seutp for the other endstops.

so before I uplaod it, I'm curious, what can go wrong if I set this?  Do I need to enable the pullup resistor at all?

on the ramps the pause switch is connected on the ramps to the gnd and sig pins on xmax.

Thank youimageimage

Comments

  • RepetierRepetier
    You connect the same like mechanical endstops. so gnd against pin and pullup enabled for the jam detection pin. 
  • shaissshaiss
    I get that but I'm trying to understand what happens if I don't enable that pullup
  • RepetierRepetier
    Without pullup you have no defined voltage. You have gnd if switch is triggered and something if not as that side is not defined. Pullup makes if 5V by default over big resistor and when gnd comes from switch it is stronger pulling signal to low.
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