#include <AT89X52.H> 
  //29．            兩點(diǎn)間溫度控制
unsigned char code dispbitcode[]={0xfe,0xfd,0xfb,0xf7, 
                                  0xef,0xdf,0xbf,0x7f}; 
unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66, 
                               0x6d,0x7d,0x07,0x7f,0x6f,0x00}; 
unsigned char dispbuf[8]={10,10,10,10,10,10,0,0}; 
unsigned char dispcount; 
unsigned char getdata; 
unsigned int temp; 
unsigned char i; 
  
sbit ST=P3^0; 
sbit OE=P3^1; 
sbit EOC=P3^2; 
sbit CLK=P3^3; 
sbit LED1=P3^6; 
sbit LED2=P3^7; 
sbit SPK=P3^5; 
bit lowflag; 
bit highflag; 
unsigned int cnta; 
unsigned int cntb; 
bit alarmflag; 
  
  
void main(void) 
{ 
  ST=0; 
  OE=0; 
  TMOD=0x12; 
  TH0=0x216; 
  TL0=0x216; 
  TH1=(65536-500)/256; 
  TL1=(65536-500)%256; 
  TR1=1; 
  TR0=1; 
  ET0=1; 
  ET1=1; 
  EA=1; 
  ST=1; 
  ST=0; 
  while(1) 
    { 
      if((lowflag==1) &&(highflag==0)) 
        { 
          LED1=0; 
          LED2=1; 
        } 
        else if((highflag==1) && (lowflag==0)) 
          { 
            LED1=1; 
            LED2=0; 
          } 
          else 
            { 
              LED1=1; 
              LED2=1; 
            } 
    } 
} 
  
void t0(void) interrupt 1 using 0 
{ 
  CLK=~CLK; 
} 
  
void t1(void) interrupt 3 using 0 
{ 
  
  TH1=(65536-500)/256; 
  TL1=(65536-500)%256; 
  
       if(EOC==1) 
         { 
           OE=1; 
           getdata=P0; 
           OE=0; 
           temp=getdata*25; 
           temp=temp/64; 
           i=6; 
           dispbuf[0]=10; 
           dispbuf[1]=10; 
           dispbuf[2]=10; 
           dispbuf[3]=10; 
           dispbuf[4]=10; 
           dispbuf[5]=10; 
           dispbuf[6]=0; 
           dispbuf[7]=0; 
          while(temp/10) 
            { 
              dispbuf[i]=temp%10; 
              temp=temp/10; 
              i++; 
            } 
          dispbuf[i]=temp;          
           if(getdata<77) 
             { 
               lowflag=1; 
               highflag=0; 
             } 
             else if(getdata>153) 
               { 
                 lowflag=0; 
                 highflag=1; 
               } 
               else 
                 { 
                   lowflag=0; 
                   highflag=0; 
                 } 
           ST=1; 
           ST=0; 
         } 
  
  P1=dispcode[dispbuf[dispcount]]; 
  P2=dispbitcode[dispcount]; 
  dispcount++; 
  if(dispcount==8) 
    { 
      dispcount=0; 
    } 
  
  if((lowflag==1) && (highflag==0)) 
    { 
      cnta++; 
      if(cnta==800) 
        { 
          cnta=0; 
          alarmflag=~alarmflag; 
        } 
      if(alarmflag==1) 
        { 
          SPK=~SPK; 
        } 
    } 
    else if((lowflag==0) && (highflag==1)) 
      { 
      cntb++; 
      if(cntb==400) 
        { 
          cntb=0; 
          alarmflag=~alarmflag; 
        } 
      if(alarmflag==1) 
        { 
          SPK=~SPK; 
        }        
      } 
      else 
        { 
          alarmflag=0; 
          cnta=0; 
          cntb=0; 
        } 
}