步进电机的速度控制通过单片机发出的脉冲频率来实现。软件分配方式，可以采用调整两个控制字之间的时间间隔来实现。硬件脉冲分配方式，可以控制步进脉冲的频率来调速。-stepper motor speed control of the MCU by pulse frequency is to be achieved. Software distribution, and the adjustment can be used to control two characters between the ti