GRBL_ESP32 tips

I made a CNC that uses a custom board I designed, and which runs GRBL_ESP32. I couldn’t find the following info easily, so I’ve written it here:

  • You can specify the enable pin for the drivers with the STEPPERS_DISABLE_PIN option. This should be used like #define STEPPERS_DISABLE_PIN GPIO_NUM_2.
  • To invert the enable signal, you can use #define DEFAULT_INVERT_ST_ENABLE 1. My board needed the enable signal to not be inverted (that’s what A4988/Trinamic TMC2208 drivers need), so I set it to 0.
  • To always keep the steppers enabled (locked) to avoid them moving, you can specify $Stepper/IdleTime=255. That’s the maximum timeout and will always keep them enabled.

Last updated on February 15, 2021. For any questions/feedback, email me at