ds1820.c

温度采集显示与PID控制

#include"w77e58.h"
#include"intrins.h"

#define uchar unsigned char
#define uint unsigned int
extern void clp_dog();

sbit DQ =P1^7;//根据实际情况定义端口
uchar bdata afc;
uchar bdata afd;
sbit ac0=afc^0;			/*定义ACC的位，利用ACC操作速度最快*/
sbit ac1=afc^1;
sbit ac2=afc^2;
sbit ac3=afc^3;
sbit ac4=afc^4;
sbit ac5=afc^5;
sbit ac6=afc^6;
sbit ac7=afc^7;

sbit cc0=afd^0;			/*定义ACC的位，利用ACC操作速度最快*/
sbit cc1=afd^1;
sbit cc2=afd^2;
sbit cc3=afd^3;
sbit cc4=afd^4;
sbit cc5=afd^5;
sbit cc6=afd^6;
sbit cc7=afd^7;


extern bit wdcgaq;//温度传感器正确标志0＝正?

void delaya(unsigned long useconds);
void delaye(uint useconds);
void delayb(uchar useconds);
bit ow_reset(void);
uchar read_byte(void);

void write_byte(uchar val);
int Read_Temperature(void);
void writ0();
void writ1();
bit read();
//延时
void delaya(unsigned long useconds)
{
unsigned long i;
  for(i=0;i<=useconds;i++)
       _nop_();
}
void delaye(uint useconds)
{
  uint i;
  for(i=0;i<=useconds;i++)
       _nop_();
}
void delayb(uchar useconds)
{
  uchar i;
  for(i=0;i<=useconds;i++)
       _nop_();
}

//读取温度
int Read_Temperature(void)
{
 union{
    uchar c[2];
    int x;
  }temp;
  if(ow_reset())
    return(0);
  clp_dog();
  write_byte(0xCC); //Skip ROM
  delaye(60);
  write_byte(0x44); // Start Conversion
  delaya(39000); 
  if(ow_reset())
     return(0);
  clp_dog();
  write_byte(0xCC); // Skip ROM
  delaye(60);
  write_byte(0xBE); // Read Scratch Pad
  delaye(60);
  temp.c[0]=read_byte();
  delaye(60);
  temp.c[1]=read_byte();
  
  return(temp.x);
}


//复位
bit ow_reset(void)
{
  DQ = 0; //pull DQ line low
  delaya(25); // leave it low for 480us
  DQ = 1; // allow line to return high
  delaye(40); // wait for presence
  //presence = DQ; // get presence signal
  wdcgaq=DQ;//无传感器或错误
  delaya(10); // wait for end of timeslot
  return(wdcgaq); // presence signal returned
}  // 0=presence, 1 = no part

//从 1-wire 总线上读取一个字节
uchar read_byte(void)
{
     uchar value = 0;
    ac0=read(); 
     delaye(80); // wait for rest of timeslot
    ac1=read(); 
     delaye(80); // wait for rest of timeslot
    ac2=read(); 
     delaye(80); // wait for rest of timeslot
    ac3=read(); 
     delaye(80); // wait for rest of timeslot
    ac4=read(); 
     delaye(80); // wait for rest of timeslot
    ac5=read(); 
     delaye(80); // wait for rest of timeslot
    ac6=read(); 
     delaye(80); // wait for rest of timeslot
    ac7=read(); 
     delaye(80); // wait for rest of timeslot
    return(value=afc);
}    
   
   

//向 1-WIRE 总线上写一个字节
void write_byte(uchar val)
{
    afc=val;
    
    if(ac0)
    	writ1();
    else writ0();
    
    if(ac1)
    	writ1();
    else writ0();
    
    if(ac2)
    	writ1();
    else writ0();
     
    if(ac3)
    	writ1();
    else writ0();
    
    if(ac4)
    	writ1();
    else writ0();
    
    if(ac5)
    	writ1();
    else writ0();
    
    if(ac6)
    	writ1();
    else writ0();
     
    if(ac7)
    	writ1();
    else writ0();
   
}
   
void writ0()
{
 DQ = 0; // pull DQ low to start timeslot
    delaye(100);
 DQ = 1;
 delaye(60);
}
void writ1()
{
    DQ = 0; // pull DQ low to start timeslot
    delayb(20);
    DQ =1;
    delaye(160); // hold value for remainder of timeslot
    
}

bit read()
{
   
    DQ = 0; // pull DQ low to start timeslot
    delayb(8);
    DQ = 1; // then return high
    _nop_();
     cc0=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc1=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc2=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc3=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc4=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc5=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc6=DQ;
     delayb(2);  //for (i=0; i<3; i++);
    cc7=DQ;
    if(afd==0xff)
    	return(1);
  else return(0);
}