I have a Mega, running GRBL v1.1 for Mega, a Protoneer CNC shield (only X & Y axes), 2 TMC2130 step drivers, using LaserGRBL software for testing. My problem: the test motor works (i.e. jogs) when plugged into the Y step driver, but not the X step driver. What I've done:
- Set Vref on both step drivers correctly for the motor
- replaced the X driver with another TMC2130 to make sure it's not the X step driver
- checked connectivity between TMC2130 motor outputs and the stepper cable
- In GRBL, re-assigned X/Y step/dir to different pins; result Y still works, X still doesn't
inspired by this post: Solved::Arduino mega 2560 pin layout for GRBL - Installation & Troubleshooting - Arduino Forum
- checked voltages on the X step driver: they're the same as on the Y driver (VIMOT 12V, VCC 5V, cfg pins open)
- right now, the X/Y limit switches are both unconnected, their pin state is the same (HIGH)
Any other suggestions how to diagnose this?
get an oszi and look what comes out of the pins.
Rather than change things why not swap them over?
Swap the motors and see if the fault follows the motor, if not then it looks like the software. Try and write simple code just to test if both motors move.
If they do then it is definitely something wrong with the software and pin assignments.
Replace the motor coils with LEDs and a suitable resistor to see if they blink when the motors are commanded to move.
Hi,
In GRBL, re-assigned X/Y step/dir to different pins; result Y still works, X still doesn't
inspired by this post:
What pins did you re-assign the controls to?
Tom... 
Grumpy_Mike:
Swap the motors
Forgot to list that: all tests done with the same motor, i.e. the same motor works with the Y step driver, but not the X axis.
In any case, I think I found the fault: there's no continuity between the "X Step" pin on the edge of the CNC board and the "Step" female pin in the X driver socket. There is continuity for the corresponding points for the Y axis. I'll disassemble the project and try to find a break in the trace or whatever is causing this.
Thanks for all suggestions.