Fast DECAY for DRV8825 seems to solve the vibration problem while holding the current position, but there is virtually no torque.
Start porting the trapezoidal trajectory generator to Piccolo.
Implement the trapezoidal trajectory generator state machine.
Modeled each trajectory generator as separate active objects, but the lowest priority generator seems to be getting starved out.  Looking into this.
Slow down the GPIO in sampling frequency, to avoid false positive in detecting SW3.
Implement DIR pins for the 3 steppers on GPIO3,4,5