18b20.c

18B20温度测量

#include<reg51.h>
//********************** DS18B20 指令********************* *********
#define ds18B20_READ_ROM          0x33      // 读ROM指令
#define ds18B20_MATCH_ROM         0x55      // 匹配ROM指令
#define ds18B20_SKIP_ROM          0xCC      // 跳过ROM指令
#define ds18B20_SEARCH_ROM        0xF0      // 搜索ROM指令
#define ds18B20_ALARM_SEARCH      0xEC      // 报警搜索指令
#define ds18B20_WRITE_SCRATCHPAD  0x4E      // 写暂存寄存器指令
#define ds18B20_READ_SCRATCHPAD   0xBE      // 读暂存寄存器指令
#define ds18B20_COPY_SCRATCHPAD   0x48      // 复制暂存寄存器指令
#define ds18B20_CONVERT_T         0x44      // 启动温度转换指令
#define ds18B20_RECALL_E2         0xB8      // 重新调出E2PROM的数据
sbit DQ=P1^7;  //将P1.0口模拟时钟输出
//-------------------------------------------------------------------
//函数名称:delay1820
//入口参数:i
//函数功能:延时子程序,实现(16*i+24)us的延时
//-------------------------------------------------------------------
void delay1820(unsigned int i)
{
while(i--);
}
//-------------------------------------------------------------------
//函数名称:Init_DS18B20
//入口参数:无
//函数功能:初始化函数
//-------------------------------------------------------------------
Init_DS18B20(void)
{
unsigned char deceive_ready;
DQ = 1; //DQ复位
delay1820(8); //稍做延时
DQ = 0; //单片机将DQ拉低
delay1820(80); //精确延时 大于 480us
DQ = 1; //拉高总线
delay1820(14);
deceive_ready=DQ; //稍做延时后 如果x=0则初始化成功 x=1则初始化失败
delay1820(20);
DQ=1;
return(deceive_ready);
}
//-------------------------------------------------------------------
//函数名称：ReadOneBit
//入口参数：无
//函数功能：读1bit子程序
//--------------------------------------------------------------------
unsigned char ReadOneBit(void)
{
unsigned char i;
bit b;
DQ=0;
i++;
DQ=1;
i++;
i++;
b=DQ;
i=8;
while(i>0) i--;
return(b);

}
//-------------------------------------------------------------------
//函数名称：WriteOneBit
//入口参数：bit
//函数功能：写1bit子程序
//--------------------------------------------------------------------
void WriteOneBit(unsigned char bitval)
{
bit btmp;
unsigned i;
btmp=bitval&0x01;
if(btmp)
 {
  DQ=0;
  i++;
  i++;
  DQ=1;
  i=8;
  while(i>0)
  i--;
 }
else
 {
  DQ=0;
  i=8;
  while(i>0)
  i--;
  DQ=1;
  i++;
  i++;
  }

}
//-------------------------------------------------------------------
//函数名称：ReadOneChar
//入口参数：无
//函数功能：读1byte子程序
//--------------------------------------------------------------------
ReadOneChar(void)
{
unsigned char i=0;
unsigned char dat = 0;
for (i=8;i>0;i--)
{
DQ = 0; // 给脉冲信号
dat>>=1;
DQ = 1; // 给脉冲信号
if(DQ)
dat|=0x80;
delay1820(4);
}
return(dat);
}
//-------------------------------------------------------------------
//函数名称：ReadOneChar
//入口参数：dat
//函数功能：写1byte子程序
//--------------------------------------------------------------------
WriteOneChar(unsigned char dat)
{
unsigned char i=0;
for (i=8; i>0; i--)
{
DQ = 0;
DQ = dat&0x01;
delay1820(5);
DQ = 1;
dat>>=1;
}
delay1820(4);
}
//-------------------------------------------------------------------
//函数名称：Config18B20
//入口参数：无
//函数功能：配置18B20
//--------------------------------------------------------------------
void Config18b20()
{
Init_DS18B20();
WriteOneChar(ds18B20_SKIP_ROM); //skip rom
WriteOneChar(ds18B20_WRITE_SCRATCHPAD); //write scratchpad
WriteOneChar(0x02); //上限
WriteOneChar(0x00); //下限
WriteOneChar(0x7f); //set 11 bit (0.125)
Init_DS18B20();
WriteOneChar(ds18B20_SKIP_ROM); //skip rom
WriteOneChar(ds18B20_COPY_SCRATCHPAD); //保存设定值
Init_DS18B20();
WriteOneChar(ds18B20_SKIP_ROM); //skip rom
WriteOneChar(ds18B20_RECALL_E2); //回调设定值
}

//void ReadTemperature()
/*void main()
{
unsigned char a=0,b=0;
unsigned int temp;
unsigned char id;
//Config18b20();
Init_DS18B20();
WriteOneChar(ds18B20_SKIP_ROM); // 跳过读序号列号的操作
WriteOneChar(ds18B20_CONVERT_T); // 启动温度转换
delay1820(500);
Init_DS18B20();
WriteOneChar(ds18B20_SKIP_ROM); //跳过读序号列号的操作
WriteOneChar(ds18B20_READ_SCRATCHPAD);
//读取温度寄存器等（共可读9个寄存器） 前两个就是温度
a=ReadOneChar(); //读取温度值低位
b=ReadOneChar(); //读取温度值高位
id=ReadOneChar(); //读取温度值高位
DQ=1;
temp=b<<8; //最终数据在a和b中，怎么处理你自己用吧 呵呵
temp=temp|a;
temp=temp*0.625; //这是转换成具体温度值，1点代表0.625°C
delay1820(2000);
}
*/

void main()
{
bit id_bit, cmp_id_bit;
unsigned  char id_bit_number,LastDeviceFlag;
unsigned char  LastDiscrepancy,LastFamilyDiscrepancy;
unsigned char Last_zero,search_direction;
unsigned char ROM_NO[8];
Init_DS18B20();
if(LastDeviceFlag==1)
  {
    LastDiscrepancy=0;
    LastFamilyDiscrepancy=0;
    LastDeviceFlag=0;
  }
else
  {
   id_bit_number=1;
   Last_zero=0;
   WriteOneChar(0xf0);
   do
    {
     id_bit=ReadOneBit();
     cmp_id_bit=ReadOneBit();
     if((id_bit==0x01)&&(cmp_id_bit==0x01)
       {
        LastDiscrepancy=0;
        LastFamilyDiscrepancy=0;
        LastDeviceFlag=0;
       }
     if((id_bit==0x00)&&(cmp_id_bit==0x00)
       {
         if(id_bit_number==LastDiscrepancy)
           {
            search_direction=1;
            //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
            id_bit_number=id_bit_number+1;
           }
         else
           {
            if(id_bit_number>LastDiscrepancy)
              {
                search_direction=0;
                Last_zero=id_bit_number;
                if(Last_zero<9)
                  {
                    LastFamilyDiscrepancy=Last_zero;
                    //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
                    id_bit_number=id_bit_number+1;
                  }
                else
                  {
                   //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
                   id_bit_number=id_bit_number+1;
                  }
              }
             else
              {
                //将ROM_NO中第id_bit_number位的值赋给search_direction
                if(search_direction==0)
                   {
                    Last_zero=id_bit_number;
                    if(Last_zero<9)
                      {
                         LastFamilyDiscrepancy=Last_zero;
                          //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
                          id_bit_number=id_bit_number+1;
                      }
                    else
                      {
                        //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
                        id_bit_number=id_bit_number+1;
                      }
                   }
                else
                   {
                     //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
                     id_bit_number=id_bit_number+1; 
                   }    
              }
           }
       }
      esle
       {
         search_direction=id_bit;
         //将search_direction位赋给ROM_NO中的第id_bit_number位,并向1-wire总线上参与搜索的器件发送该位
         id_bit_number=id_bit_number+1;
       }

     id_bit_number=id_bit_number+1;
    }
   while(id_bit_number<65);
   LastDiscrepancy=last_zero;
   if(LastDiscrepancy==0)
     {
      LastDeviceFlag=1; 
      if(LastDiscrepancy==LastFmailyDiscrepancy)
        {
        LastFamilyDiscrepancy=0;
        return 1;
        }
      else
        {
         return 1;
        }  
     }
   else
     {
       if(LastDiscrepancy==LastFmailyDiscrepancy)
        {
        LastFamilyDiscrepancy=0;
        return 1;
        }
       else
        {
         return 1;
        }  
     }  
  }
}
/*void main()
{
 bit n1,n2,n3;
 Init_DS18B20();
 WriteOneChar(0xf0);
 n1=ReadOneBit();
 n2=ReadOneBit();
 WriteOneBit(0x00);
 n1=0;
 n2=0;
 n1=ReadOneBit();
 n2=ReadOneBit();
 WriteOneBit(0x00);
 n1=0;
 n2=0;
 n1=ReadOneBit();
 n2=ReadOneBit();
 WriteOneBit(0x00);
 n1=0;
 n2=0;
 n1=ReadOneBit();
 n2=ReadOneBit();
 WriteOneBit(0x01);
 n1=0;
 n2=0;
 n1=ReadOneBit();
 n2=ReadOneBit();
 WriteOneBit(0x00);
 n1=0;
 n2=0;
 n1=ReadOneBit();
 n2=ReadOneBit();
}
*/