Step & Direction Command Source
Step & direction command source, or simply stepper emulation, is a method in which the position of the motor is controlled through two digital inputs: the STEP and DIRECTION pins. The DIRECTION pin indicates direction of movement, and each falling edge on the STEP pin increases (or decreases, depending on the DIRECTION value) the position of the rotor by the number of counts stipulated in the Step value object (one by default). As a consequence of this design, to achieve larger movements in small time periods it is necessary to either deliver a train of pulses through the STEP pin at a high frequency rate (increasing encoder cost and EMIs due to switching) or to increase the value on the Step value object (losing resolution), hence not being suitable for high accuracy and responsivity applications. Nevertheless, its simplicity makes it acceptable for less demanding applications.