说明：  美国Allegro公司推出的A3972型串口控制器是步进电机微步距驱动专用电路。一个A3972外加一个简易CPU即可实现二相步进电机的32微步距驱动。文中介绍该电路的特点、引脚功能和工作原理，并给出A3972的典型应用电路，该电路已成功地应用在某步进电机伺服系统中
(A3972 type serial controller produced by Allegro is microstepping motor driver dedicated circuit. A A3972 with a simple CPU to achieve the 32 phase stepper motor micro stepping driving. This paper introduces the characteristics, pin functions and working principles of the circuit, and gives a typical application circuit of A3972, which has been successfully applied to a stepper motor servo system)