SKR - Dual End Stop - Homing Issue

I have setup my SKR with Dual End Stops, but I have a few questions/issues.

  1. While the Docs say to wire/use NC switches, when I do this, any ‘open’ switch shows TRIGGERED. (by open, I mean the switch is not depressed)

  2. My dual Z end stops are currently setup to Home Down, and even with the above concern, seems to work fine. (I prefer it to Home Down to Auto Square, as homing down seems to be easier)

  3. However, my X axis is not working as well. The limit switch, shows TRIGGERED, when not homed, and when I try to home X, it moves maybe 1-2mm in the + direction, not back to home. NOW, if I OPEN the Limit switch (by depressing it) it DOES seem behave correctly.

  4. While having a Z Max would be GREAT to prevent the Z rails from poping out of the lower guide, Is there a way to set a ‘max’ in the firmware? (I understand that if it isnt homed correctly, that software/firmware limit will be inaccurate.

  5. Is it still correct that if I have my Z switches set for Zmin, that I wont be able to use the Zprobe?

You don’t have the V1 firmware installed. They are at MarlinBuilder releases.


The V1 firmware solves a lot of this, like Jeff said.

If for some reason you really don’t want to use it…

  1. NC switches are generally recommended because if they become disconnected they will read as triggered. This generally results in something that will not damage your machine. In order to use them, you must enable the pullup resistors, and set them to triggered HIGH. You must also be sure to wire the switches between SIG and GROUND. Do not connect the +5V (or +3.3V) line tot he switches at all. The pullup resistors will bring the voltage up on the signal pin when there is no path to ground through the switch, so when the switch is presses and the connection opens, the pin goes to high voltage. if you enable the pullup resistors, and set the logic to high, the switches will work as expected.

  2. Home up is generally safer, as it keeps the tool out of the way, but home down is easier to think of. Weird that this works, what does the board say if you query it with M119?

  3. See point 1

  4. You can set axis limits in Marlin.

  5. There are still ways to do this, but they aren’t easy, and aren’t the way that we generally use the software.

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@SupraGuy @jeffeb3

I am 90% sure I flashed the firmware (a DEF did to the screen). I will reattempt a firmware flash of the board.

The low rider dual endstop firmware homes up, and the endstops are NC. You can check with M115, it should say v510DL. You can send that from the screen terminal.