1.c

通过Ds1820数字温度传感器

#include <reg51.h>
#include<stdio.h>
#include<math.h>
#include<intrins.h>
sbit p1_3=P1^3;
typedef unsigned char byte;
unsigned char dispbuf[4];
byte code dtab[]={0x42,0xee,0x58,0x68,0xe4,0x61,0x41,0xea,0x40,0x60,0x00};
void delay(int ticks)
{
    for(;ticks>0;ticks--);
}
bit ow_reset(void)
{
    bit presence;
    p1_3=0;
    delay(29);
    p1_3=1;
    delay(3);
    presence=p1_3;
    delay(25);
    return(presence);
}
byte ow_read_byte(void)
{
    byte i;
    byte value=0;
    for(i=8;i>0;i--)
    {
        value>>1;
        p1_3=0;
        p1_3=1;
        delay(0);
        if(p1_3)
        value|=0x80;
        delay(5);
    }
    return(value);
}
void ow_write_byte(char val)
{
    byte i;
    for(i=8;i>0;i--)
    {
        p1_3=0;
        p1_3=val&0x01;
        delay(7);
        p1_3=1;
        val=val/2;
    }
    delay(5);
}
 unsigned int Read_Temperature(void)
 {
   unsigned int x;
   byte c[2];
   ow_reset();
   ow_write_byte(0xCC);
   ow_write_byte(0xBE);
   c[0]=ow_read_byte();
   c[1]=ow_read_byte();
   ow_reset();
   ow_write_byte(0xCC);
   ow_write_byte(0x44);
   x=c[0]+c[1]*256;
   return(x);
 }
 void change(unsigned int x)
{
   int i=0,m;
   if((x)>0x7d0)
   {
    m=(~x+1)*0.625;
    dispbuf[3]=10;
    dispbuf[2]=m/100;
    dispbuf[1]=(m-dispbuf[2]*100)/10;
    dispbuf[0]=m-dispbuf[2]*100-dispbuf[1]*10;
   }
   else
   {
    m=x*0.0625;
    dispbuf[3]=0;
    dispbuf[2]=m/100;
    dispbuf[1]=(m-dispbuf[2]*100)/10;
    dispbuf[0]=m-dispbuf[2]*100-dispbuf[1]*10;
   }
}
void scandisp(void)
{
    byte posi=0xfe,i,j,temp;
    for(i=0;i<4;i++)
    {
        temp=dispbuf[i];
        temp=dtab[temp];
        for(j=0;j<200;j++)
        {P2=posi;P0=temp;}
        posi<<=1;posi|=0x01;
    }
}
 main()
 {
  int t;
  while(1)
  {
    Read_Temperature();
    change();
    for(t=0;t<100;t++)
    scandisp(); 
  }
 }