035_ds18b20数字温度传感器测温.c

本代码是关于DS18B20数字温度传感器测温

#include <reg52.H>
#include <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=P3^6;
bit sflag;


bit resetpulse(void)
{
  unsigned char i;

  DQ=0;
  for(i=255;i>0;i--);
  for(i=255;i>0;i--);
  DQ=1;
  for(i=60;i>0;i--);
  for(i=60;i>0;i--);
  return(DQ);
  for(i=200;i>0;i--);
  for(i=60;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--);
          for(j=35;j>0;j--);
          DQ=1;
        }
        else
          {
            DQ=0;
            for(j=2;j>0;j--);
            for(j=2;j>0;j--);
            DQ=1;
            for(j=33;j>0;j--);
            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--);
      for(j=10;j>0;j--);
      if(DQ==1)
        {
          temp=temp | 0x80;
        }
        else
          {
            temp=temp | 0x00;
          }
      for(j=200;j>0;j--);
      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=displaycount|(P2 & 0xf8);
  displaycount++;
  if(displaycount==8)
    {
      displaycount=0;
    }

  timecount++;
  if(timecount==255)
    {
      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];
      while(result/10)
        {
          displaybuf[x]=result%10;
          result=result/10;
          x++;
        }
      displaybuf[x]=result;
      if(sflag==1)
        {
          displaybuf[x+1]=17;
        }
      x=readdata[0] & 0x0f;
      x=x<<1;
      displaybuf[0]=(dotcode[x])%10;
      displaybuf[1]=(dotcode[x])/10;
      while(resetpulse());
      writecommandtods18b20(0xcc);
      writecommandtods18b20(0x44);
    }
}