Under the functional testing on our engineering board mounted on DRV8818, it occured step-out of the stepping motor. We cheked waveform on DIR terminal, and found large noise on it. Also we checked DIR with terminal floating, but noise is still exist on it.
DIR Terminal: Connected on PCB
DIR Terminal: Floating
Question
(1) Noise on DIR terminal is caused by lifting device GND. Is this correct?
(2) Is signal GND separate from power GND? (or is it not separated?)
(3) Is there any effective measre? An external pull down resistor(zero-ohm?) or an external capacitor will be effectice on this?
Best Regards,
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