Testing Firmware for LR2 on a SKR 1.4 Turbo with TMC2209 drivers

This is what I’ve collected around the nets to get a SKR 1.4 Turbo to work with my LowRider2 with dual endstops. It works for me and I’d still like to add a few features. Anyone who wants to give it a whirl and report back, please do. The endstops are wired and programmed for NO, which SHOULD not require the removal of the DIAG pin on the drivers, but I had already removed mine so I have no way of actually testing that.

Also, steps/mm may need to be adjusted. I had to drop mine by half.


What drivers are you using?

TMC2209 drivers

Yeah, these:

Should be 100,100,400.

Yup! I knew they were buried in there somewhere.

Hi, if I use this firmware, do I need to change the bed dimensions somewhere? I am using SKR 1.4 Turbo and TMC 2209s and yours is the nearest I have found to my board and drivers.

There are options for bed dimensions in Marlin found here. I have, what are roughly a 24"x48" dimension here. I have been able to jog past them, I don’t know what it will actually do in an automated run.

The bed dimensions only affect how far the printer is willing to travel during homing. So if they are set to 200x200mm, then you need to be withing 200mm of the endstops before homing.

You’d need to enable soft stops for them to actually stop the movement.

Thank you very much. I think I have flashed the new firmware. Will have to wait till the morning so I can test it. Is there new firmware for the BTT TFT35 e-3 V3.0? that relates to CNC rather than 3D printers?

There is some. It is a first draft, not perfect.

The TFT35 e-3 v3.0 firmware that I use for my LR2 is included with the first release I have on the github. Its the other files with it. Also found here.

TheExpertNoob thank you for all your help. Could I please ask if you are using your steppers wired in series or are you running each one from a separate driver? Also do you do automatic levelling of the z axis? I just don’t understand how automatic levelling works if the z axis steppers are wired in series as surely the same commands would be going to both steppers even if the end stops are showing they are not level. Or have I completely misunderstood how this works?

Yep. The only adjustment you can make is to start the machine with the Z square.

Thanks for the reply Jeff. So would it not be better to run the 5 steppers from 5 drivers and not wire them in series?

It would only give you the advantage of auto square. You can’t do that with 3 drivers.

Thanks for the link to the firmware for the TFT35. Ryan has put that you need a SD card of 8Gb or lower. I am having trouble getting one, will a 32Gb card not work?

I made some minor adjustments to the firmware. I found out why I had steps_per_unit set to 200, 200, 800, 200. I planned on setting microsteps to 32 from the default of 16 and just forgot. Also increased stepper current from 800mA to 900mA (I’m running a 12v 6A power supply, I didn’t need it to fail on me) Steppers now should max out at 4.5A leaving me with 1.5A for a laser. (well probably more like 1.2A if you include the controller itself and LCD) As I planned on powering the laser from the Heater1 pin once I can get a Laser module. Anyone want to donate one for SCIENCE!?

My local walmart has 2GB SD cards in the electronics section for like $4, any drug stores with a photo kiosk MIGHT have them too.

I managed to get a SD card from a car spares shop. All the steppers appear to be working ok. I can’t control the Lowrider by the touch screen. It says no printer attached, but works from the Marlin screen. The end stops are not working but I believe that is because I haven’t removed the pin from the TMC 2209s, so that is my next job. I have checked the baud rate and changed it to 250000, would you have any idea why the touch screen is not connecting please? Which software is best for communicating from the computer? I have tried repetier and it connected and controlled the steppers, but I am finding difficult sending a M119 command to it. Do you enter it as a script and then run the script? I cannot find where to enter a command line M119. Sorry to be a pest.

Just a quick update. Have now bent the pins out of the way on the TMC 2209s and found out why my TFT says no printer attached. It was quite correct as I hadn’t attached one of the cables, it was still in the box. I have also found out how to send M119 commands and have some end stops working. Will try to get the others working in a couple of days.