#include"reg51.h"
#define uchar unsigned char
#define uint unsigned int
#define switch_temp P1
uint A,pwm,time;
uchar period=500;
uchar high=300;

void logic(void)
 {
  A=P3;
  A=A&0x1C;
  switch(A)
    {
	  case 0x14:
	            switch_temp=0x68;break;
	  case 0x04:
	            switch_temp=0x64;break;
	  case 0x0C:
	            switch_temp=0xA4;break;
	  case 0x08:
	            switch_temp=0xB0;break;
	  case 0x18:
	            switch_temp=0xD0;break;
	  case 0x10:
	            switch_temp=0xB8;break;
	 }
  }

void timer1(void) interrupt 3 
 {
   TH1=256-50;
   TL1=TH1;
   time++;
   if(time=high)
      pwm=1;
   else if(time=period)
      {
	   time=0;pwm=1;
	   }
 }

 main()
 {
  TMOD=0x20;
  TH1=256-50;
  TL1=TH1;
  ET1=1;
  TR1=1;
  EA=1;
  pwm=!pwm;
  while(1)
   {
   	if(pwm==1)
	 logic();
	else
	    {
		 P1=0xFF;
		 }
	}
  }