Stepper motor drive board.

This design is a stepper motor open-loop driver board, using STC15W408AS microcontroller as the main control, 12V power input, using two A4950 motor drives, the maximum current can reach 3.5A. The three inputs are isolated by optocoupler, even if the driver board is blown up, the main control will not be blown. The four DIP switches can adjust the subdivision and current (torque). The serial port interface is reserved for burning programs or for monitoring and debugging.

The DIP switch is 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] From 00-> 01-> 10-> 11, the current increases in sequence, and the torque also increases in sequence, which can be adjusted according to the actual application. (Be careful to increase the heat sink, otherwise the temperature will be too high and shut down)