The ULN2003 chip is a commonly used integrated drive circuit chip that can be used to drive various types of loads, including DC motors. However, the ULN2003 chip itself cannot directly reverse the motor, because it can only control the forward rotation or stop of the motor. To achieve motor reversal, the positive and negative rotation of the motor needs to be controlled by an external line.
Usually the realization method is to connect an H-bridge circuit or bipolar conversion circuit at the output end of ULN2003, and control the forward and reverse of the motor by controlling this circuit.
In this way, when the input signal changes, the motor can be reversed, so as to achieve the purpose of controlling the positive and negative rotation of the motor.
With 2003 drive stepper motor to achieve positive and negative rotation!
I just finished the graduation design of the stepper motor drive, using single-chip microcomputer control, but also used 2803, if only forward can not reverse, I think it is the software problem, I suggest you check the control motor reverse operation program