Error message: Unable to read tmc uart 'stepper_z' register IFCNT

General Discussion
1

Basic Information:

Printer Model: TL-D3 Pro IDEX PRinter
MCU / Printerboard: Octopus Pro v1.1 / BTT Pi v1.2
klippy.log
klippy(3).log (388.7 KB)
printer(8).cfg (11.2 KB)

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Describe your issue:

When attempting to home my printer, I am receiving “Unable to read tmc uart ‘stepper_z’ register IFCNT” error.

I just recently rewired up my TL-D3 using an Octopus Pro v1.1 board and TMC2209s.

I was using virtual endstops for all stepper motors, then realized that was not going to work for the Z axis for accuracy issues, and so swapped over to microswitches.
At this time, all motors did run when trying to home, but the Z-endstops were not homing accurately.

Now the motherboard is inside the printer-base, which required rewiring everything. When I attempt to home, the two x-motors and y motors home properly, but when it gets to z, klipper throws an “Unable to read tmc uart ‘stepper_z’ register IFCNT”

I have seen other users online having issues with board power, but unless I accidentally removed the jumper to let it run on the main-board power instead of the motor-power slots, this shouldn’t be an issue - all the stepper-motors are powered in the same way, and the others are functioning properly.

Full disclosure - during a part of this, early on when I just finished my rewiring, I powered on the printer and heard a “pop,” and nothing was running. I powered off the printer, replaced some potentially deficient wiring jobs from the Power Supply to the board, checked that all the fuses were good, and restarted it without any similar indications. I would suspect that nothing blew since the fuses were good, but that is always a possibility.

I am hoping to get some guidance before a lengthy hardware troubleshooting process.

Troubleshooting Done:

  1. Turned it off and back on again.
  2. Double-checked my diag, endstop, and UART pins against my config file.
  3. Visual and nasal methods of detecting inadvertent release of magic blue smoke.

Suspected Causes:
1 - I made a mistake in my config and I just don’t know enough about Klipper to troubleshoot it.
2 - Something may have been misplaced when rewiring.

I do not think it is a power-issue. When doing research, other users found that they needed to power their drivers from jumpering from main power to the motor-power directly, but the Octopus has the ability to set up the small jumpers next to the drivers for this, which I have done. As mentioned, doing this the X and Y motors still home, and Z motors used to home before when I was trying to use virtual endstops.

2

Resolved (Sort of):
I swapped Stepper Motor Drivers with a known good one (Swapped Y and Z)
I suspect one or more of the pins wasn’t making contact, because both are working now.

Now I just can’t get it to move down when homing. When I hit “home” the Z-axis just sets its current position as zero. It will move up, but will not move down past what it thought was minimum position.

3

You have set homing_retract_dist to 0 which disable the second homing move.

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Thanks. I set it to 5 and it moved up 5mm, now I’m getting “Endstop z still triggered after retract” so I suspect I may have a wiring issue for the end-stops.

5

… And of course, this was also user-caused.

I swapped the optical end-stops (passing a signal whenever not interrupted) for microswitches (passing a signal when depressed).

So all I had to do was invert the pin signals with “!”. It now homes.

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