Stepper motor driver board V2.0 (5V)

This design is an open-loop driver board for stepper motors. It uses the STC15W408AS microcontroller as the main control, 12V power input, and two A4950 motor drivers. The maximum current can reach 3.5A. The three inputs are isolated by optocouplers. Even if the driver board explodes, the main control will not explode. Four dip switches can adjust the subdivision and current (torque). The reserved serial port interface can be used to burn programs or monitor and debug. The dip switches are used to adjust the subdivision and current. Subdivision [1:2] = 00: no subdivision, = 01: x2 subdivision, = 10: x4 subdivision, = 11: x8 subdivision. Current [3:4] The current increases in sequence from 00->01->10->11, and the torque also increases in sequence. It can be adjusted according to the actual application. (Note that the heat sink should be enlarged, otherwise the temperature will be too high to shut down)