ds18b20.c~

基于GPRS的远程温度采集控制系统, 嵌入式系统, C源代码, 供做嵌入式开发及远程控制的朋友参考.

#include<stdio.h>
#include<unistd.h>
#include"44B.H"


static void delay_1us(void)//1us延时函数

{
    asm("nop");
	
}

static void delay_nus(unsigned int n)//N us延时函数

{

unsigned int i=0;

for (i=0;i<n;i++)

delay_1us();

}

static void delay_1ms(void)//1ms延时函数

{

unsigned int i;

for (i=0;i<1140;i++);

}

static void delay_nms(unsigned int n)//N ms延时函数

{

unsigned int i=0;

for (i=0;i<n;i++)

delay_1ms();

}
static void tempconvert(unsigned char temH,unsigned char temL)
{
     unsigned char L,H;        
     H=(temL >> 4)+(temH<<4);    //温度整数部分
     L=(temL & 0x0F)? 5:0;    //温度小数部分.
     printf("%d.%d\n",H,L);
    }

static unsigned char InitDs18b20(void) //复位函数定义
{
   unsigned char  RX=1; //函数返回值设置
  //rPCONF=0x01; //PF0输出口
   rPCONF=0x1255;
   rPDATF=0x01;
   delay_nus(5);
   rPDATF=0x0; //PF0输出0，拉低
   delay_nus(500);
   delay_1us();
   rPDATF=0x01; //低脉冲时间500us已过，PF0置高
  // delay_nus(100);
   rPCONF=0x0000; //改为输入口，进行读值
   //printf("delay 100");
   delay_nus(100);
   if((rPDATF & 0x01)==0) //读到PF0口为低时说明存在脉冲收到
       {
         //printf("%x\n",rPDATF);
         RX=0;//success!
       }
    else  
       RX=1;//fail!
     delay_nus(480);
    // rPCONF=0x01;//output
   rPCONF=0x1255;  
   rPDATF=0x01;
   return  RX; //函数返回RX值，在收到存在脉冲时RX为零
}

static unsigned char DS18B20_ReadOneBit_1()
{
     unsigned char bReturnValue=0;
     //rPCONF=0x01;
    rPCONF=0x1255;
    rPDATF=0x01;
    //delay_1us();
    rPDATF=0x0;
    delay_1us();
    rPDATF=0x01;//a sign read   
    rPCONF=0x0000;
    delay_nus(15);
    if(rPDATF&0x01)
     {
          bReturnValue=1;
     }
    delay_nus(50);
    return bReturnValue;
}
static unsigned char DS18B20_ReadOneBit_0()
{
    unsigned char bReturnValue=1;
    rPCONF=0x1255;
    rPDATF=0x01;
    rPDATF=0x0;
    delay_1us();
    rPCONF=0x0000;
    delay_nus(15);
    if((rPDATF&0x01)==0)
         bReturnValue=0;
     rPCONF=0x1255;
     rPDATF=0x01;
     delay_nus(50);
     return bReturnValue;
}
static unsigned char ReadOneByte(void)
{
   unsigned char uci;
   unsigned char ucReadData;
   unsigned char ucMaskCode;
    ucReadData = 0;
    ucMaskCode = 0x01;
   for(uci=0; uci<8; uci++)
       {
         if(DS18B20_ReadOneBit_1()==1)
          {
            ucReadData |= ucMaskCode;
          }
         ucMaskCode <<= 1 ;
      }
   return ucReadData;


}
static void DS18B20_WriteOneBit_0()
{
     rPCONF=0x1255;
     //rPCONF=0x01;
      rPDATF=0x01;
    // delay_1us();
     rPDATF=0x0;
     delay_nus(15);
     
     delay_nus(15);
     delay_nus(30);
     rPDATF=0x01;
}
static void DS18B20_WriteOneBit_1()
{
     //rPCONF=0x01;
     rPCONF=0x1255;
     rPDATF=0x01;
    // delay_1us();
     rPDATF=0x0;
     delay_nus(15);
     rPDATF=0x01;
     delay_nus(15);
     delay_nus(30);
}
				    
static void WriteOneByte(unsigned char ucWriteData)
{
    unsigned char uci;
    unsigned char ucTemp;
    ucTemp = ucWriteData;
   for(uci=0; uci<8; uci++)
    {
        if(ucTemp & 0x01)
           {
                DS18B20_WriteOneBit_1();
           }
        else
          {
             DS18B20_WriteOneBit_0();
           }
       ucTemp >>= 1 ;
    }

}

static void ConfigDs18b20 (void)
{
   
     if( InitDs18b20()==1)
             {
       printf("fail") ; //初始化
       exit(1);
            }    
     WriteOneByte(0xcc);  //skip rom
     WriteOneByte(0x4e);  //write scratchpad
     WriteOneByte(0x19);  //温度上下限
     WriteOneByte(0x1a); 
     WriteOneByte(0x7f);     //set 11 bit (0.0625)
     InitDs18b20(); 
     WriteOneByte(0xcc);  //skip rom
     WriteOneByte(0x48);  //保存设定值
     InitDs18b20(); 
     WriteOneByte(0xcc);  //skip rom
     WriteOneByte(0xb8);  //回调设定值
     InitDs18b20();
}

float ReadTemperature(void)
 {
     unsigned char tempL=0;  //临时变量低位
     unsigned char tempH=0; //临时变量高位
     //unsigned char TH=0;//上限
     //unsigned char TL=0;//下限
     unsigned char con=0;
     float temperature; //温度值
     unsigned char ucTempDataBuff[9]; //用于映像DS18B20内容字节内容的缓冲区
      ConfigDs18b20();			  
  if( InitDs18b20()==1)
       {
       printf("error") ; //初始化
       exit(1);
      }    
        printf("OK!\n") ;
        WriteOneByte(0xcc); //跳过读序列号的操作
        WriteOneByte(0x44); //启动温度转换
                     //转换需要一点时间，延时
        delay_nms(750);
        InitDs18b20(); //初始化
        WriteOneByte(0xcc); //跳过读序列号的操作
        WriteOneByte(0xbe); //读温度寄存器（头两个值分别为温度的低位和高位）
        ucTempDataBuff[0] = ReadOneByte();
        ucTempDataBuff[1] = ReadOneByte();
        ucTempDataBuff[2] = ReadOneByte();
        ucTempDataBuff[3] = ReadOneByte();
        ucTempDataBuff[4] = ReadOneByte();
        ucTempDataBuff[5] = ReadOneByte();
        ucTempDataBuff[6] = ReadOneByte();
	     ucTempDataBuff[7] = ReadOneByte();
	     ucTempDataBuff[8] = ReadOneByte();
        for(con=0;con<9;con++)
	       printf("%x\n",ucTempDataBuff[con]);
       tempL=ucTempDataBuff[0];
       tempH=ucTempDataBuff[1];
       tempconvert(tempH,tempL);  

       temperature=((tempH*256)+tempL)*0.0625;
       return  temperature;
}