ds18b20.lst

这是单片机实验板比较齐全的程序

C51 COMPILER V7.50   DS18B20                                                               05/27/2007 09:10:56 PAGE 1   


C51 COMPILER V7.50, COMPILATION OF MODULE DS18B20
OBJECT MODULE PLACED IN ds18b20.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE ds18b20.c BROWSE DEBUG OBJECTEXTEND

line level    source

   1          //DS1820 C51 子程序 
   2          //这里以11.0592M晶体为例，不同的晶体速度可能需要调整延时的时间 
   3          sfr P3=0xB0;
   4          sbit DQ =P3^5;
   5          //根据实际情况定义端口
   6          typedef unsigned char byte; 
   7          typedef unsigned int word;
   8          //延时 
   9          void delay(word useconds)
  10          { 
  11   1              for(;useconds>0;useconds--); 
  12   1      }
  13          //复位 
  14          byte ow_reset(void) 
  15          { 
  16   1              byte presence; 
  17   1              DQ = 0;//pull DQ line low 
  18   1              delay(29); // leave it low for 480us 
  19   1              DQ = 1; // allow line to return high 
  20   1              delay(3); // wait for presence 
  21   1              presence = DQ; // get presence signal 
  22   1              delay(25); // wait for end of timeslot 
  23   1              return(presence); // presence signal returned 
  24   1      } // 0=presence, 1 = no part
  25          //从 1-wire 总线上读取一个字节 
  26          byte read_byte(void) 
  27          { 
  28   1              byte i;
  29   1              
  30   1              byte value = 0;
  31   1              for (i=8;i>0;i--)
  32   1              {
  33   2                      value>>=1;
  34   2                      DQ = 0; // pull DQ low to start timeslot 
  35   2                      DQ = 1; // then return high
  36   2                      delay(1); //for (i=0; i<3; i++);
  37   2                      if(DQ)value|=0x80; 
  38   2                      delay(6);   // wait for rest of timeslot 
  39   2              } 
  40   1              return(value);
  41   1      }
  42          //向 1-WIRE 总线上写一个字节 
  43          void write_byte(char val) 
  44          { 
  45   1              byte i; 
  46   1              for (i=8; i>0; i--) // writes byte, one bit at a time
  47   1              { DQ = 0; // pull DQ low to start timeslot 
  48   2              DQ = val&0x01; 
  49   2              delay(5); // hold value for remainder of timeslot 
  50   2              DQ = 1; 
  51   2              val=val/2;
  52   2              } 
  53   1              delay(5); 
  54   1      }
  55          //读取温度 
C51 COMPILER V7.50   DS18B20                                                               05/27/2007 09:10:56 PAGE 2   

  56          char Read_Temperature(void)
  57          {
  58   1              union{ 
  59   1                      byte c[2]; 
  60   1                      int x; 
  61   1              }temp;
  62   1              ow_reset(); 
  63   1              write_byte(0xCC); // Skip ROM 
  64   1              write_byte(0xBE); // Read Scratch Pad 
  65   1              temp.c[1]=read_byte(); 
  66   1              temp.c[0]=read_byte(); 
  67   1              ow_reset(); 
  68   1              write_byte(0xCC); //Skip ROM 
  69   1              write_byte(0x44); // Start Conversion 
  70   1              return temp.x>>4; 
  71   1      }


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =    172    ----
   CONSTANT SIZE    =   ----    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =   ----       2
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.


C51 COMPILATION COMPLETE.  0 WARNING(S),  0 ERROR(S)