利用51单片机实现对一个四相步进电机的控制和相应的数据显示。包括四相电机的启动和停止、控制正转和反转并显示其实际旋转方向及相应的速度等级。-51 single-chip implementation of a four-phase stepper motor control and data display. Including the start and stop of the four-phase motor control forward and reverse, and displays