步进电机的调速一般是改变输入步进电机的脉冲的频率来实现步进电机的调速，因为步进电机每给一个脉冲就转动一个固定的角度，这样就可以通过控制步进电机的一个脉冲到下一个脉冲的时间间隔来改变脉冲的频率，延时的长短来具体控制步进角来改变电机的转速，从而实现步进电机的调速。在本设计方案中采用AT89C51型单片机内部的定时器改变CP脉冲的频率从而实现对步进电机的转速进行控制，实现电机调速与正反转的功能。-Stepper motor speed control is generally to change the input pulse frequency of the stepper motor stepper motor speed to achieve, because the stepper motor to a pulse on each rotation a fixed angle, so that you can control the stepper motor by a pulse to the next pulse interval to change the pulse frequency, the length of delay to the specific control step angle to change the motor speed in order to achieve the stepper motor speed. Design used in this type of microcontroller AT89C51 CP internal timer to change the frequency of the pulse in order to achieve the speed of the stepper motor to control the motor speed control and reversing function.