#include<reg52.h>

sbit KEY1 = P3^1; //定义调速按键

sbit PWM = P1^5; //定义调速端口

unsigned char CYCLE; //定义周期T=x*0.1ms

unsigned char PWM_ON ; //定义高电平时间

void delay(unsigned int cnt)

{

while(--cnt);

}

main()

{

unsigned char PWM_Num;

TMOD |=0x01;

TH0=(65536-1000)/256;

TL0=(65536-1000)%256;

IE= 0x82;

TR0=1;

CYCLE = 10;

while(1)

{

if(!KEY1)

{

delay(10000);

if(!KEY1)

{

PWM_Num++;

if(PWM_Num==4)

PWM_Num=0;

switch(PWM_Num)

{

case 0:P0=0x06;PWM_ON=0;break;

case 1:P0=0x5B;PWM_ON=4;break;

case 2:P0=0x4F;PWM_ON=6;break;

case 3:P0=0x66;PWM_ON=8;break;

default:break;

}

}

}

}

}

void tim(void) interrupt 1 using 1

{

static unsigned char count;

TH0=(65536-1000)/256;

TL0=(65536-1000)%256;

if (count==PWM_ON)

{

PWM = 1;

}

count++;

if(count == CYCLE)

{

count=0;

if(PWM_ON!=0)

PWM = 0;

}

}