2) playing with stepper motors.

I hooked up a nema 17 stepper motor via a DRV8825 Stepper Motor Driver 
basically using the same led tutorial bone script to drive the GPIO pins to 
run it.

The DRV8825 current limit instructions and youtube videos are unclear how 
to set up.  I learned the hard way and wrecked a few of them in the 
process. The way i found to set them up was to wire them up completely 
under no power (make sure to use the 3.3VDC power from the BBG and do not 
use the 5VDC) with the motor disconnected.  Then power them up first the 
BBG then the external power supply for the stepper motor. Then the correct 
voltage between the ground (common BBG and external PS) and the 
potentiometer cover can be read.) I set the voltage to .6VDC for testing.

ISSUE FOUND:
Bonescript is not really fast enough or even intend to run stepper motors 
by togging the pin outputs. Even at slow speeds there would be numerous 
missed steps and poor behavior. My oscilloscope showed this to be true at 
the BBG and not after the DRV8825.

SOLUTION:
Don't us bonescript.  Now the fun begins, next try Python. 

End Entry 2



On Sunday, November 13, 2016 at 4:09:06 PM UTC-6, Chris M wrote:
>
> Some thoughts and findings as I begin to learn the BBG (Beaglebone Green) 
>

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