Tristate RAMPS pins in klipper

[leadinglights]

Basic Information:

Printer Model: Custom Delta
MCU / Printerboard: Pi 4 & RAMPS
klippy.log

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Describe your issue: In Klipper, is it possible to toggle a pin on a RAMPS mcu between 0V output and high impedance? - i.e., tristate the pin.

Significance: I am trying to get a dual Z probing method working on a Delta printer. One Z probe is a dockable probe used only for bed mapping. The second probe is under the bed and detects nozzle contact to set the Z reference. Using cloakedcode’s dockable probe module I can get the bed mapping working well, but I can’t get the sense to swap over to use the underbed sensor. This should work if I can disconnect the sense switches for “probe docked” and “probe attached” from ground and attached instead to a pin which can be set to ground or to open circuit (high impedance) and use the pull-ups to do the rest. Setting the normally ground to high impedance should spoof a “sled attached” state.

Video of the dual probing working with clunky macros on https://www.youtube.com/watch?v=DQXM4nrcsr4

Thanks for any help you can give.

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klippy.log (948.1 KB)

[koconnor]

Hi,

Alas, I don’t know of a way to do this in Klipper today. It’s possible to do it by writing code, but this functionality is not (to my knowledge) exported via macros or configuration.

-Kevin

[leadinglights]

Thank you, Kevin. I did manage to find a solution without needing to tristate a pin - setting the pin marked “Invert Sled Sense” to +ve gave the required signal and allowed the sled to work with cloakedcode’s dockable probe module both for probing with the sled or the nozzle. The diagram below may clarify.

Mike.