DRV8847: Position detection of stepper

Hey Nison,

You'll need an encoder to detect the position of a stepper motor.  Typically stepper motor controls just assume the motor didn't skip any steps and wasn't moved by hand since the last time it as homed (using limit switches or stall detection).  

Here's an application note about Closed Loop Stepper Motor Design With Encoder for StallDetection Reference Design. 

Regards,

Jacob