temp.c

DS18b20完整源码

#include "Temp.h"
#include "..\main\port.h"
#include "..\main\ext_reg.h"
#include <intrins.h>

#include "..\comm\serial.h"

#define  TEMP_BEGIN      0
#define  TEMP_CONVERT    1 
#define  TEMP_READ       2  
#define  TEMP_DONE       3

sbit  DQ = P1^1;
// sbit PULSE = P1^2;
uchar xdata   m_Temp_Buff[10];
bit   bdata   b_Temp_Flag;
uchar xdata   m_Temp_State;

uchar code crc_table[256] = {  0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65,
                             157,195, 33,127,252,162, 64, 30, 95,  1,227,189, 62, 96,130,220,
                     	      35,125,159,193, 66, 28,254,160,225,191, 93,  3,128,222, 60, 98,
                    	     190,224,  2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255,
                     	      70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89,  7,
                    	     219,133,103, 57,186,228,  6, 88, 25, 71,165,251,120, 38,196,154,
                     	     101, 59,217,135,  4, 90,184,230,167,249, 27, 69,198,152,122, 36,
                    	     248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91,  5,231,185,
                    	     140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205,
                     	      17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80,
                    	     175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238,
                    	      50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115,
                    	     202,148,118, 40,171,245, 23, 73,  8, 86,180,234,105, 55,213,139,
                    	      87,  9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22,
                    	     233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168,
                     	     116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53};


void Temp_Init()
{  
   DQ=1;
   DS18b20_ReadID();
   DS18b20_Config();
   m_Temp_State = TEMP_BEGIN;
}
 
void Temp_Update()
{
   uchar j; 

   switch(m_Temp_State)
   {
     case TEMP_BEGIN:      
      DS18b20_Init();
      if(b_Temp_Flag)
       { 
         DS18b20_Write(0xcc);  // skip ROM 
         DS18b20_Write(0x44);  // temp convert
         m_Temp_State = TEMP_CONVERT;
       }
      break;

     case TEMP_CONVERT: 
      DS18b20_Init();
      if(b_Temp_Flag)
       { 
         DS18b20_Write(0xcc);  // skip ROM 
         DS18b20_Write(0xbe);  // read temp 
         m_Temp_State = TEMP_READ;
       }      
      else
       {
         m_Temp_State = TEMP_BEGIN;
       }
      break;

     case TEMP_READ:
      DS18b20_ReadBytes(9,&m_Temp_Buff[0]);
      m_Temp_State = TEMP_DONE;
      break; 

     case TEMP_DONE: 
       j = DS18b20_GetTemp();
       if(j!=0xff)
        {
           m_Temp = j+m_Param2-128;
        }
       m_Temp_State = TEMP_BEGIN;
      break;

     default:
      m_Temp_State = TEMP_BEGIN;
      break;
   }
}    

void delay(uchar us)
{
   us = us+us;   // 双倍速
   while(us--); 
}

void DS18b20_Init()
{
   DQ = 1;
   _nop_();
   DQ = 0;
   delay(80);    // delay 530us
   DQ = 1;
   delay(14);    // delay 100us
   if(DQ==0)
    { b_Temp_Flag = 1; }   // delect 1820 success!
   else
    { b_Temp_Flag = 0; }   // delect 1820 fail!
   delay(20);    
   DQ = 1;
}

void DS18b20_Write(uchar wr)  // 写入单字节
{
  uchar j;
  
  for(j=0;j<8;j++)
    {
       DQ = 0;
       _nop_();
       DQ = wr&0x01;
       delay(5);            // delay 45us
       DQ = 1;
       wr >>= 1;
    }
}

uchar DS18b20_Read(void)      // 读单字节
{
  uchar j;
  uchar result = 0;

  for(j=0;j<8;j++)
   {
     DQ = 0;
     result >>= 1;
     DQ = 1;
     if(DQ==1)
       result |= 0x80;
     delay(4);                
   }
  return result;
}

void DS18b20_ReadBytes(uchar n, uchar* p)
{
  uchar j;
  
  for(j=0;j<n;j++)
   {
     *(p+j) = DS18b20_Read();
   }
}

void DS18b20_ReadID(void)
{
   DS18b20_Init();
   DS18b20_Write(0x33);   // Read ROM
   DS18b20_ReadBytes(8,&m_Temp_Buff[0]);
}

void DS18b20_Config()
{
   DS18b20_Init();
   DS18b20_Write(0xcc);    // skip ROM
   DS18b20_Write(0x4e);    // write scratchpad
   DS18b20_Write(0x19);    // 上限
   DS18b20_Write(0x1a);    // 下限
   DS18b20_Write(0x7f);    //  set 11 bit (0.125)
   DS18b20_Init();
   DS18b20_Write(0xcc);    // skip ROM
   DS18b20_Write(0x48);    // 保存设定的值
   DS18b20_Write(0xcc);    // skip ROM
   DS18b20_Write(0xb8);    // 回调设定的值
}

uchar DS18b20_GetTemp()
{
   uchar j,crc=0;
   uint tmp;

   for(j=0;j<9;j++)
    { 
       crc = crc_table[crc^m_Temp_Buff[j]];
    }
 
   if(crc==0)
    {
       tmp = m_Temp_Buff[1]*256+m_Temp_Buff[0];
       //tmp = tmp*0.0625;
       tmp = tmp>>4; 
       return (uchar)tmp;
    }
   
   return 0xff;
}