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标题: DS18B20测量温度数据传送 [打印本页]

作者: バ幸福De右岸 时间: 2016-2-25 12:34
标题: DS18B20测量温度数据传送

*  晶振:11.0592MHZ

******************************************************************/
#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit DS=P2^2;          //define interface
uint temp;          // variable of temperature
uchar flag1;          // sign of the result positive or negative
sbit wela1=P2^4;             //段选信号的锁存器控制
sbit wela2=P2^5;
sbit wela3=P2^6;             //段选信号的锁存器控制
sbit wela4=P2^7;             //位选信号的锁存器控制
sbit beep=P2^3;
unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
                     0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
unsigned char code table1[]={0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,
                     0x87,0xff,0xef};

void delay(uint count)    //delay
{
  uint i;
  while(count)
  {
i=200;
while(i>0)
i--;
count--;
  }
}
void dsreset(void)    //send reset and initialization command
{
  uint i;
  DS=0;
  i=103;
  while(i>0)i--;
  DS=1;
  i=4;
  while(i>0)i--;
}

bit tmpreadbit(void)    //read a bit
{
uint i;
bit dat;
DS=0;i++;       //i++ for delay
DS=1;i++;i++;
dat=DS;
i=8;while(i>0)i--;
return (dat);
}

uchar tmpread(void) //read a byte date
{
  uchar i,j,dat;
  dat=0;
  for(i=1;i<=8;i++)
  {
j=tmpreadbit();
dat=(j<<7)|(dat>>1);
  }
  return(dat);
}

void tmpwritebyte(uchar dat) //write a byte to ds18b20
{
  uint i;
  uchar j;
  bit testb;
  for(j=1;j<=8;j++)
  {
testb=dat&0x01;
dat=dat>>1;
if(testb)    //write 1
{
   DS=0;
   i++;i++;
   DS=1;
   i=8;while(i>0)i--;
}
else
{
   DS=0;    //write 0
   i=8;while(i>0)i--;
   DS=1;
   i++;i++;
}

  }
}

void tmpchange(void)  //DS18B20 begin change
{
  dsreset();
  delay(1);
  tmpwritebyte(0xcc);  // address all drivers on bus
  tmpwritebyte(0x44);  //  initiates a single temperature conversion
}

uint tmp()             //get the temperature
{
  float tt;
  uchar a,b;
  dsreset();
  delay(1);
  tmpwritebyte(0xcc);
  tmpwritebyte(0xbe);
  a=tmpread();
  b=tmpread();
  temp=b;
  temp<<=8;          //two byte  compose a int variable
  temp=temp|a;
  tt=temp*0.0625;
  temp=tt*10+0.5;
  return temp;
}

void display(uint temp)                      //显示程序
{

uchar A1,A2,A2t,A3;
A1=temp/100;
A2t=temp%100;
A2=A2t/10;
A3=A2t%10;
wela4=0;

P0=table[A1];             //显示百位
wela1=1;
delay(2);
wela1=0;
delay(1);

P0=table1[A2];             //显示十位
wela2=1;
delay(2);
wela2=0;
delay(1);

P0=table[A3];             //显示个位
wela3=1;
delay(2);
wela3=0;
delay(1);
}

void main()
{
uchar a;
  do
  {
tmpchange();
      for(a=10;a>0;a--)
      {
               display(tmp());
      }
      if(temp>=310)       //当温度超过31度，蜂鸣器便会报警。
            {
                     P1=0x00;
                     beep=0;
            }
            else
            {
                     beep=1;
                     P1=0xff;
            }
  } while(1);
}

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