步进电机，可以控制转速，正反转，数码管显示转速，

主要讲诉运用matlab实现步进电机抛物曲线，指数曲线的牛顿迭代的运算，算出精确的脉冲时间间隔-The main complaint about the use of matlab stepper motor parabolic curve, the exponential curve of Newton iterative calculation to calculate accurate pulse interval