介绍了基于单片机用PWM实现直流电机调整的基本方法，直流电机调速的相关知识，及

PWM调整的基本原理和实现方法。重点介绍了基于MCS一51单片机的用软件产生PWM信号的途径，并

介绍了一种独特的通过采用计数法加软件延时法实现PWM信号占空比调节的方法。对于直流电机速度控

制系统的实现提供了一种有效的途径。-Introduced based microcontroller PWM DC motor adjusted to achieve the basic method, knowledge of DC motor speed control, and PWM to adjust the basic principles and implementation methods. Highlights based on MCS-51 microcontroller with a PWM signal generated by the software approach, and describes a unique software through the use count plus time delay method of the PWM signal duty cycle adjustment method. DC motor speed control system for the realization of an effective way.