Connecting Geckodrive G540 using G3 20 Pin Side Connector


Work in progress

Reason for doing this - simplify the wiring of the stepper motors.

The Masso G3 controller has a 20 pin connector on the right hand side of the controller. The pin-out information is listed in the Masso Documentation.

The wiring sequence is sufficiently different to the G540 DB25 IDC connector that a small interface board is required. I am planning to use a vertical mount PCB DB25 plug in "strange and interesting ways" by surface mounting the PCB pins to each side of a double sided circuit board. The gap between the two rows of PCB pins is 1.8mm while the typical PCB is 1.6mm in thickness, this means I need to create solder bridges to span the 0.2mm gap on one side of the board (I can assure you that isn't a challenge - I have more problems avoid solder bridges where there is a 1 mm gap).

A small 3D printed shroud and it will probably look quite professional.


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The PCBs finally arrived (pandemics and couriers don't mix) and subsequently soldered them up with the following connection methods to the 20 wire ribbon cable:
  • Vertical box header
  • Horizontal box header
  • Transition plug

The vertical box header, although it works, has too much overall vertical height once the cable is plugged in.

The horizontal (90 ) box header is better but I prefer the transition plug style connection due to the compact footprint.

One issue I noticed is the signals appear to be inverted on the 20 pin side connector. Asked a question in the forums but no response so far - probably need to raise a ticket to confirm.

Otherwise the custom board works as intended (tested all 4 axis without issue).


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just bought a masso, so im super new. I was browsing the forums for best way to wire my gecko 540 and came across your post.

Are these side mounts for sale?

Can the inverted signals be correct in the software?

I only have 1 e-stop currently, can i just use a wire to trick the gecko into working?




The signal can be inverted on the F1 screen (each axis has a check box "invert direction") - it is more a minor annoyance that the documentation doesn't mention it.

There are a couple of options:
  • I provide you with the Gerber ZIP file that you can upload to PCBWay to get 10 boards made (first order is effectively free, just pay shipping)
  • I have one board that I have not used yet, you will need to solder the D25 and appropriate header
  • I have a couple of "duds" which would require de-soldering a part and replacing with the correct one (will take a bit longer)

I have attached the relevant files (including STL for the 3D printed shell). The thumbscrews can be purchased from Jaycar (Part # PM0859).

EDIT - On PCBWay's website:
  • Select "PCB Instant Quote"
  • Then select "Quick-order PCB: Upload gerber files & autofill parameters"
  • Click "Add Gerber File" and select the Gerber ZIP file (download from the attachment to this message)
  • Press calculate and then order

I am flying out to the Pilbara region on Monday for the week (work reasons).

@breezy - is there any method to send a direct message via the forum?


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Your G540 may or may not have the charge pump / watch dog circuit enabled.

The charge pump / watch dog needs to be disabled when using a G540 with a Masso controller.

Information on how to disable the charge pump / watch dog circuit can be found on Geckodrive's website.


If your willing to solder and make the connections / ribbon cable, etc so i can just "plug and play" , i am willing to pay you for your troubles. I live in southern california --> my email is



Photo of revised connector with a jumper to select an alternative MASSO controller axis (for example when slaving the Y axis with the B axis, then map MASSO B axis to the G540 A axis).


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