#include 
     
      #include 
      
       #define NOP() _nop_()#define uchar unsigned char#define uint unsigned intunsigned int temp;float f_temp;sbit ds = P2^2;sbit dula=P2^6;   //数码管段选线sbit wela=P2^7;   //数码管位选线unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,0x87,0xff,0xef};     //不带小数点的编码void delay15us();void delayUS(int us); //us=50为600us/*当us=1时，延迟时间为30us，当us=2时，延迟时间为43us当us=3时，延迟时间为56us，可以看出基本的调用时间为17us，每增加一次循环增加13us，*/void reset();void writeBit(char dat);void writeByte(unsigned char val);char readBit(void);char readByte(void);void convert(void);unsigned int getTemperature(void);void display(unsigned char num,unsigned char dat);void dis_temp(unsigned int t);void main(void){    dula=0;      wela=0;      while(1)      {          convert();      dis_temp(getTemperature());     }    }void delayUS(int us){    while(us--);    //    NOP();}void delay15us(){    NOP();NOP();NOP();NOP();NOP();NOP();    NOP();NOP();NOP();NOP();NOP();}void reset(){    ds = 0;    delayUS(37);//480us    ds = 1;    delayUS(37);//对照着ds18b20 复位时序图写}void writeBit(unsigned char dat){    ds = 0;    delay15us();    if(dat == 1)        ds = 1;    delay15us();    delay15us();    delay15us();    ds = 1;}void writeByte(unsigned char val){    unsigned char dat;    int i;    for(i = 8; i > 0; i--)    {        dat = val & 0x01;        writeBit(dat);        val = val>>1;    }    }char readBit(void){        char dat;    ds = 0;    NOP();    ds = 1;    //应该在0~15us的时间内，ds18b20都会在数据线上写数据，可以再这之后写几个nop（）；    delay15us();    dat = ds;    delayUS(3);    return dat;     }char readByte(void){    uchar i,temp,dat;      dat=0;      for(i=1;i<=8;i++)      {        temp=readBit();         //在读暂存器时，数据以位0为最低有效位从单总线移出        dat=(temp<<7)|(dat>>1);   //读出的数据最低位在最前面，这样刚好一个字节在DAT里     }     return(dat);}void convert(void){    reset();    writeByte(0xCC);    writeByte(0x44);}unsigned int getTemperature(void){    uchar LSB, MSB;    reset();    writeByte(0xCC);    writeByte(0xBE);    LSB = readByte();    MSB = readByte();        temp = MSB;    temp = (temp<<8) | LSB;    f_temp=temp*0.0625;      //温度在寄存器中为12位 分辨率位0.0625°     temp=f_temp*10+0.5;    //乘以10表示小数点后面只取1位，加0.5是四舍五入      f_temp=f_temp+0.05;       return temp;         //temp是整型}void display(uchar num,uchar dat){  uchar i;  dula=0;  P0=table[dat];  dula=1;  dula=0;  wela=0;  i=0XFF;  i=i&(~((0X01)<<(num)));  P0=i;  wela=1;  wela=0;      delayUS(150);}void dis_temp(uint t){  uchar i;  i=t/100;  display(0,i);  i=t%100/10;  display(1,i+10);  i=t%100%10;  display(2,i);}