由单片机P2口输出的脉冲信号来模拟4相线圈产生的电流，来控制步进电机，用4个LED亮灭的快慢来模拟电机的速度，用它们的亮灭顺序来模拟电机的相序和拍数。-P2 port output from the MCU to simulate the four-phase pulse signal generated by the coil current to control the stepper motor, with 4 LED light blinking speed to simulate the motor speed, with their bright destroy the motor in order to simulate the phase sequence and the shoot a few.