PWM.rar_单片机产生pwm

#include<reg52.h> // IO定义 sbit L=P1^3; //左边电机使用P1_3口 sbit R=P1^2; //右边电机使用P1_2口 sbit LS=P3^1; sbit RS=P3^0; unsigned char i,sgin=0; void InitTimer0(void) { TMOD = 0x01; TH0 = 0x00; TL0 = 0x00; EA = 1; ET0 = 1; TR0 = 1; } void delay20() //误差 -0.86805555556us { unsigned char a,b; for(b=155;b>0;b--) for(a=52;a>0;a--); } void delay(char t) { switch(t) { case 12: TH0 = 0xfb;TL0 = 0xb4;break; //1200ms case 14: TH0 = 0xfa;TL0 = 0xe2;break; //1430ms case 15: TH0 = 0xfa;TL0 = 0xa1;break; //1500ms case 16: TH0 = 0xfa;TL0 = 0x58;break; //1600ms case 18: TH0 = 0xf9;TL0 = 0x8e;break; //1800ms default :break; } TR0=1; while(!sgin); sgin=0; } void forward() //前进 { L=1; delay(18); L=0; R=1; delay(12); R=0; delay20(); //20ms的低电平时间 } void back() //后退 { L=1; R=0; delay(12); L=0; R=1; delay(18); R=0; delay20(); //20ms的低电平时间 } void left_turn() //原地左转 { L=1; R=1; delay(12); L=0; R=0; delay20(); //20ms的低电平时间 } void right_turn() //原地右转 { L=1; R=1; delay(18); L=0; R=0; delay20(); //20ms的低电平时间 } void stop() //原地右转 { L=1; R=1; delay(15); L=0; R=0; delay20(); //20ms的低电平时间 } void left_f() { R=1; delay(12); //右快左慢前进 R=0; L=1; delay(16); L=0; delay20(); //20ms的低电平时间 } void right_f() { R=1; delay(14); R=0; L=1; delay(18); L=0; delay20(); //20ms的低电平时间 } void left_b() { R=1; delay(18); R=0; L=1; delay(14); L=0; delay20(); //20ms的低电平时间 } void right_b() { R=1; delay(16); R=0; L=1; delay(12); L=0; delay20(); //20ms的低电平时间 } void main() { unsigned char comd; InitTimer0(); P3=0X00; for(;;) { comd=P2&0x0f; switch(comd) { case 1: left_f();break; case 2: forward(); break; case 3: right_f();break; case 4: left_turn(); break; case 5: stop(); break; case 6: right_turn(); break; case 7: left_b();break; case 8: back(); break; case 9: right_b();break; default: stop(); break; } } } void Timer0Interrupt(void) interrupt 1 { sgin=1; }