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＃i nclude <AT89X52.H>

＃i nclude <INTRINS.h>



unsigned char code displaybit[]={0xfe,0xfd,0xfb,0xf7,

                                 0xef,0xdf,0xbf,0x7f};

unsigned char code displaycode[]={0x3f,0x06,0x5b,0x4f,

                                    0x66,0x6d,0x7d,0x07,

                                    0x7f,0x6f,0x77,0x7c,

                                    0x39,0x5e,0x79,0x71,0x00,0x40};

unsigned char code dotcode[32]={0,3,6,9,12,16,19,22,

                                25,28,31,34,38,41,44,48,

                                50,53,56,59,63,66,69,72,

                                75,78,81,84,88,91,94,97};

unsigned char displaycount;

unsigned char displaybuf[8]={16,16,16,16,16,16,16,16};

unsigned char timecount;

unsigned char readdata[8];



sbit DQ=P3^7;

bit sflag;





bit resetpulse(void)

{

  unsigned char i;



  DQ=0;

  for(i=255;i>0;i--);

  DQ=1;

  for(i=60;i>0;i--);

  return(DQ);

  for(i=200;i>0;i--);

}



void writecommandtods18b20(unsigned char command)

{

  unsigned char i;

  unsigned char j;


  for(i=0;i<8;i++)

    {

      if((command & 0x01)==0)

        {

          DQ=0;

          for(j=35;j>0;j--);

          DQ=1;

        }

        else

          {

            DQ=0;

            for(j=2;j>0;j--);

            DQ=1;

            for(j=33;j>0;j--);

          }

      command=_cror_(command,1);    

    }

}



unsigned char readdatafromds18b20(void)

{

  unsigned char i;

  unsigned char j;

  unsigned char temp;



  temp=0;

  for(i=0;i<8;i++)

    {

      temp=_cror_(temp,1);

      DQ=0;

      _nop_();

      _nop_();

      DQ=1;

      for(j=10;j>0;j--);

      if(DQ==1)

        {

          temp=temp | 0x80;

        }

        else

          {

            temp=temp | 0x00;

          }

      for(j=200;j>0;j--);

    }

  return(temp);

}



void main(void)

{

  TMOD=0x01;

  TH0=(65536-4000)/256;

  TL0=(65536-4000)%256;

  ET0=1;

  EA=1;



  while(resetpulse());

  writecommandtods18b20(0xcc);

  writecommandtods18b20(0x44);

  TR0=1;

  while(1)

    {

      ;

    }

}



void t0(void) interrupt 1 using 0

{

  unsigned char x;

  unsigned int result;



  TH0=(65536-4000)/256;

  TL0=(65536-4000)%256;

  if(displaycount==2)

    {

      P0=displaycode[displaybuf[displaycount]] | 0x80;

    }

    else

      {

        P0=displaycode[displaybuf[displaycount]];

      }

  P2=displaybit[displaycount];

  displaycount++;

  if(displaycount==8)

    {

      displaycount=0;

    }



  timecount++;

  if(timecount==150)

    {

      timecount=0;

      while(resetpulse());

      writecommandtods18b20(0xcc);

      writecommandtods18b20(0xbe);

      readdata[0]=readdatafromds18b20();

      readdata[1]=readdatafromds18b20();

      for(x=0;x<8;x++)

        {

          displaybuf[x]=16;

        }

      sflag=0;

      if((readdata[1] & 0xf8)!=0x00)

        {

          sflag=1;

          readdata[1]=~readdata[1];

          readdata[0]=~readdata[0];

          result=readdata[0]+1;

          readdata[0]=result;

          if(result>255)

            {

              readdata[1]++;

            }

        }

      readdata[1]=readdata[1]<<4;

      readdata[1]=readdata[1] & 0x70;

      x=readdata[0];

      x=x>>4;

      x=x & 0x0f;

      readdata[1]=readdata[1] | x;

      x=2;

      result=readdata[1];