实现直流电机的1-7级pwm调速以及停止功能，同时将级数在数码管上显示 #include "reg52.h"#include<intrins.h> //#include "math.h"sbit QiTin = P3^0;//启停按键sbit duan = P2^6;//数码段sbit wei = P2^7;//数码位sbit NanBeiHong = P1^0;sbit NanB