学会电机调速，掌握中国速度

PWM的生成方法

先用户设定一个比较值，然后计数器定时自增。
当计数器<比较值，输出0
当计数器>比较值，输出1

main.c

#include <REGX52.H>
#include"delay.h"
#include"key.h"
#include"Nixie.h"
#include"Timer0.h"unsigned char Counter,Compare;
unsigned char KeyNum,Speed;
sbit Motor=P1^0;void main()
{Timer0_Init();while(1){KeyNum=Key();if(KeyNum==1){Speed++;Speed%=4;if(Speed==0){Compare=0;}if(Speed==1){Compare=50;}if(Speed==2){Compare=75;}if(Speed==3){Compare=100;}}Nixie(1,Speed);}	}void Timer0_Routine() interrupt 1
{TL0 = 0x9C;		//设置定时初值TH0 = 0xFF;		//设置定时初值Counter++;Counter%=100;if(Counter<Compare){Motor=1;}else{Motor=0;}
}

delay.c

void Delay(unsigned int xms)		//@12.000MHz
{while(xms){unsigned char i, j;i = 2;j = 239;do{while (--j);} while (--i);xms--;
}
}

delay.h

#ifndef _DELAY_H__
#define _DELAY_H__
void Delay(unsigned int xms);#endif

key.c

#include <REGX52.H>
#include "Delay.h"/*** @brief  获取独立按键键码* @param  无* @retval 按下按键的键码，范围：0~4，无按键按下时返回值为0*/
unsigned char Key()
{unsigned char KeyNumber=0;if(P3_1==0){Delay(20);while(P3_1==0);Delay(20);KeyNumber=1;}if(P3_0==0){Delay(20);while(P3_0==0);Delay(20);KeyNumber=2;}if(P3_2==0){Delay(20);while(P3_2==0);Delay(20);KeyNumber=3;}if(P3_3==0){Delay(20);while(P3_3==0);Delay(20);KeyNumber=4;}return KeyNumber;
}

key.h

#ifndef __KEY_H__
#define __KEY_H__unsigned char Key();#endif

Nixie.c

#include <REGX52.H>
#include "Delay.h"	//包含Delay头文件//数码管段码表
unsigned char NixieTable[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};//数码管显示子函数
void Nixie(unsigned char Location,Number)
{switch(Location)		//位码输出{case 1:P2_4=1;P2_3=1;P2_2=1;break;case 2:P2_4=1;P2_3=1;P2_2=0;break;case 3:P2_4=1;P2_3=0;P2_2=1;break;case 4:P2_4=1;P2_3=0;P2_2=0;break;case 5:P2_4=0;P2_3=1;P2_2=1;break;case 6:P2_4=0;P2_3=1;P2_2=0;break;case 7:P2_4=0;P2_3=0;P2_2=1;break;case 8:P2_4=0;P2_3=0;P2_2=0;break;}P0=NixieTable[Number];	//段码输出//Delay(1);				//显示一段时间//P0=0x00;				//段码清0，消影
}

Nixie.h

#ifndef __NIXIE_H__
#define __NIXIE_H__void Nixie(unsigned char Location,Number);#endif

Timer0.c

#include <REGX52.H>/*** @brief  定时器0初始化，100us@12.000MHz* @param  无* @retval 无*/
void Timer0_Init(void)
{TMOD &= 0xF0;		//设置定时器模式TMOD |= 0x01;		//设置定时器模式TL0 = 0x9C;		//设置定时初值TH0 = 0xFF;		//设置定时初值TF0 = 0;		//清除TF0标志TR0 = 1;		//定时器0开始计时ET0=1;EA=1;PT0=0;
}

Timer0.h

#ifndef __TIMER0_H__
#define __TIMER0_H__void Timer0_Init(void);#endif