The 2 logic level control lines of the Step and Direction interface automatically sets the correct phase direction and current level for proper operation based on the step mode you have selected. This significantly reduces the complexity of micro-stepping the motor on your microprocessor both from a software and firmware point of view. You can reduce the I/O lines needed from your microprocessor from upwards of 10 lines to 2 and significantly free up processing time. Commutation tables in the microprocessor are no longer required.