说明：  一个51 单片机程序步进电机控制 设计硬件电路和单片机程序，实现对四相步进电机的运动控制，包括正反向的速度控制和角度控制。 STC89C51、四位数码管、步进电机、ULN2003
(A stepper motor control 51 single-chip program designed hardware and SCM process, to achieve the four-phase stepper motor motion control, including forward and reverse speed control and angle control. STC89C51, four digital control, stepper motor, ULN2003)