sht11.lst

温湿度传感器驱动函数

C51 COMPILER V8.12   SHT11                                                                 07/05/2008 15:30:15 PAGE 1   


C51 COMPILER V8.12, COMPILATION OF MODULE SHT11
OBJECT MODULE PLACED IN SHT11.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE SHT11.c BROWSE DEBUG OBJECTEXTEND

line level    source

   1          #include <REG52.H>
   2          #include "intrins.h"      /*Keil library (is used for _nop()_ operation)*/ 
   3          #include "math.h"         /*Keil library*/ 
   4          #include "stdio.h"        /*Keil library*/
   5          #include "absacc.h"
   6          #include "12864s.h"
   7          
   8          #define ACK 1
   9          #define noACK 0
  10          #define measure_temp 0x03 //测量温度命令
  11          #define measure_humi 0x05 //测量湿度命令
  12          #define RESET        0x1e //软启动
  13          
  14          #define     uchar    unsigned   char
  15          #define     uint     unsigned   int
  16          #define     ulong    unsigned   long
  17          
  18          
  19          sbit   DATA=P1^0;
  20          sbit   SCK=P1^1;
  21          
  22          typedef union                      /*保存所测得的温度＆湿度值*/
  23          { uint  i;
  24            float f;
  25          } value;
  26          
  27          typedef struct __SYSTEMTIME__
  28          {
  29                  unsigned char gewei;
  30                  unsigned char shiwei;
  31                  unsigned char DateString1[5];
  32              unsigned char DateString2[6];
  33          }SYSTEMTIME;
  34          
  35          char write_byte(unsigned char value)
  36          // writes a byte on the Sensibus and checks the acknowledge 
  37          { 
  38   1        unsigned char i,error=0;  
  39   1        for (i=0x80;i>0;i/=2)             /*连续向右移动8位*/
  40   1        { 
  41   2          if (i & value) DATA=1;          /*把相应的位送数据线*/
  42   2          else DATA=0;                        
  43   2          SCK=1;                          /*时序脉冲，应严格按着此标准*/
  44   2          _nop_();
  45   2          _nop_();
  46   2          _nop_();                        /*大约0.5us*/       
  47   2          SCK=0;
  48   2        }
  49   1        DATA=1;                           /*释放数据线*/
  50   1        SCK=1;                            /*第9位作为响应位*/
  51   1        error=DATA;                       /*检测响应情况，如果有响应数据线就会被SHT10拉低*/
  52   1        SCK=0;        
  53   1        return error;                     /*返回1表示没响应*/
  54   1      }
  55          
C51 COMPILER V8.12   SHT11                                                                 07/05/2008 15:30:15 PAGE 2   

  56          char read_byte(unsigned char ack)
  57          { 
  58   1        unsigned char i,val=0;
  59   1        DATA=1;                           /*释放数据线*/
  60   1        for (i=0x80;i>0;i/=2)             /*连续向右移动8位*/
  61   1        { SCK=1;                          /*clk for SENSI-BUS*/
  62   2          if (DATA) val=(val | i);        /*read bit */ 
  63   2          SCK=0;                                       
  64   2        }
  65   1        DATA=!ack;                        /*当ack＝1时拉低数据线*/
  66   1        SCK=1;                            /*clk #9 for ack*/
  67   1        _nop_();_nop_();_nop_();          /*pulswith approx. 5 us */
  68   1        SCK=0;                                                    
  69   1        DATA=1;                           /*释放数据线*/
  70   1        return val;
  71   1      }
  72          
  73          void transstart(void)
  74          {
  75   1          DATA=1; 
  76   1          SCK=0;                   //初始状态
  77   1          _nop_();
  78   1          SCK=1;
  79   1          _nop_();
  80   1          DATA=0;
  81   1          _nop_();
  82   1          SCK=0;
  83   1          _nop_();_nop_();_nop_();
  84   1          SCK=1;
  85   1          _nop_();
  86   1          DATA=1;
  87   1              _nop_();
  88   1          SCK=0;
  89   1      }
  90          
  91          void connectionreset(void)//复位：当DATA线处于高低平时，触发SCK9次以上（含9次），此后应接发一个"传输开始"