A parallel port interface circuit for computer control applications involving multiple stepper motors

A parallel port interface circuit was designed, fabricated and tested for programmable control of multiple stepper motors used in a robotic manipulator arm, and a linear position table. The robotic arm built in-house had four degrees of freedom through the use of four stepper motors, and the position table required one stepper motor for linear transmission. The interface circuit consisted of a tristate buffer driver, a decoder circuit, a phase sequence generator circuit, and a power output circuit. A menu driven QBASIC program was developed for controlling the robotic arm and the position table. When the program is stopped, it displays the current position of the robotic arm and the position table. The entire circuit and the program worked accurately.