Steppers going crazy until UCCNC starts?

[rowka]

Just finished a new build with UC300ETH - UCBB setup. Using GeckoDrive 201X stepper drivers.

When I power up the hardware, the steppers start screaming and behave very erratically. I need to power down lest I fear something catastrophic will happen.

If I unplug the steppers until UCCNC loads, and THEN connect the steppers, things are much quieter and behave almost as normal (speeds and steps/unit seem way off but I'll deal with that later).

Any thoughts?

Is this a charge pump/enable issue?