sht7i.c

sht71瑞士公司生产的用来测量温湿度的芯片

#include <reg931.h>  //Microcontroller specific library, e.g. port definitions
#include <intrins.h> //Keil library (is used for _nop()_ operation)  
#include <math.h>    //Keil library  
#include <stdio.h>   //Keil library

//********************************************************************************
#define uchar unsigned char                  //数据类型定义
#define uint  unsigned int

sbit	DATA=  	P0^1;
sbit	SCK=   	P0^0;

#define  _Nop()  _nop_(),_nop_(),_nop_()     //定义空指令

#define noACK 0
#define ACK   1
                            //adr  command  r/w
#define STATUS_REG_W 0x06   //000   0011    0    //读状态寄存器
#define STATUS_REG_R 0x07   //000   0011    1    //写状态寄存器
#define MEASURE_TEMP 0x03   //000   0001    1    //测温命令
#define MEASURE_HUMI 0x05   //000   0010    1    //测湿度命令
#define RESET        0x1e   //000   1111    0    //软复位命令


typedef union 
{ unsigned int i;
  float f;
} value;



//********************************************************************************
//tools（串口输出）
//********************************************************************************
void Prints(uchar sMessage[26]);
void Putchar(uchar byte);
void Puthexbyte(uchar ch);

//char s_write_byte(unsigned char value);
//char s_write_byte(unsigned char tvalue);
/**********************************************************************
* 名称    :  Puthexbyte
* 功能描述:  将数据用16进制的格式表示
* 输入参量:  unsigned char ch
* 输出参量:  无
* 调用子程:  Putchar
* 使用方法:  例如数据puthexbyte(0x16)将向串口送出0x31  0x36，如果用串口工具的文本模式将看到"16"
--------------------------------*/
void Puthexbyte(unsigned char ch)
{
	 unsigned char i;
	 i=(ch>>4);
   if (i<=9)  Putchar(0x30+i);
	 else Putchar (0x37+i);
	 i=(ch&0x0F);
	 if (i<=9)  Putchar(0x30+i);
   	else Putchar (0x37+i);
}

/**********************************************************************
* 名称    :  prints
* 功能描述:  打印一串字符，不超过50bytes
* 输入参量:  unsigned char sMessage[50]
* 输出参量:  无
* 调用子程:  Putchar
* 使用方法:  prints("hello");
-------------------------------------*/
void Prints(unsigned char sMessage[26])
{
	 uchar k=0;
	 while(sMessage[k] != 0) 
	 {
		 Putchar(sMessage[k]);
		 k++;
	 }
}
/**********************************************************************
* 名称    :  Putchar
* 功能描述:  输出一个字节函数
* 输入参量:  unsigned char byte
* 输出参量:  无
* 调用子程:  无
* 使用方法:  直接调用，例如如果要向串口发送方波即0x55,则调用 Putchar(0x55);
-------------------------------*/
void Putchar(unsigned char byte)
{
   SBUF=byte;
   while(TI==0);
   TI=0;
}


/****************************************************
初始化串口
****************************************************/
void InitialUart()
{
   SCON=0x50;                        //SM0=0,SM1=1,模式1
                                     //REN=1,RI=0,允许接收
   SSTAT=0x20;                       //使用独立中断         
   BRGCON=0;                         //先设置成0后，才可以置位下两位
   BRGR0=0xF0;                       //7.373MHz内部RC振荡，波特率9600 
   BRGR1=0x02; 
   BRGCON=0x03;                      // enable BRG 
   IEN0=0X10;                        //开串口接收中断
   IEN1=0x40;                        //开串口发送中断
   EA=1;
}

/****************************************************
初始化IO口
****************************************************/
void InitialIO()
{
//  P2M1=0xd3;                        //SPI总线IO口
//  P2M2=0xd3;
  P1M1=0x40;                        //串口和P1.7为准双向口
  P1M2=0x40;
  P0M1=0x00;                        //置P0.0,P1.1为准双向口
  P0M2=0x00;
}


//----------------------------------------------------------------------------------
char s_write_byte(unsigned char tvalue)
//----------------------------------------------------------------------------------
// writes a byte on the Sensibus and checks the acknowledge 
{ 
	
  unsigned char i,error=0; 
  for (i=0x80;i>0;i/=2)             //shift bit for masking
  { 
  	if (i & tvalue) 
    DATA=1;                         //masking value with i , write to SENSI-BUS
    else DATA=0;                        
    SCK=1;                          //clk for SENSI-BUS
    _Nop();_Nop();_Nop();           //pulswith approx. 5 us  	
    SCK=0;
    _Nop();
  }
  DATA=1;                           //release DATA-line
  SCK=1;                            //clk #9 for ack 
  error=DATA;                       //check ack (DATA will be pulled down by SHT11)
//  Prints("DATA=");
//  Puthexbyte(DATA);
//  Prints("\r\n");
  SCK=0;
  return error;                     //error=1 in case of no acknowledge

}


//----------------------------------------------------------------------------------
char s_read_byte(unsigned char ack)
//----------------------------------------------------------------------------------
// reads a byte form the Sensibus and gives an acknowledge in case of "ack=1" 
{ 
  uchar i,val=0;
  DATA=1;                           //release DATA-line
  for (i=0x80;i>0;i/=2)             //shift bit for masking
  {
  	SCK=1;                          //clk for SENSI-BUS
  	_Nop();                         //后加
    if (DATA) val=(val | i);        //read bit  
    SCK=0;                          //后加
    _Nop(); 					 
  }
  DATA=!ack;                        //in case of "ack==1" pull down DATA-Line
  SCK=1;                            //clk #9 for ack
  _Nop();//_Nop();_Nop();           //pulswith approx. 5 us 
  SCK=0;
  _Nop();//_Nop();						                //后加
  DATA=1;                           //release DATA-line
  return val;
}



//----------------------------------------------------------------------------------
void s_transstart(void)
//----------------------------------------------------------------------------------
// generates a transmission start 
//       _____         ________
// DATA:      |_______|
//           ___     ___
// SCK : ___|   |___|   |______
{  

   DATA=1; SCK=0;                   //Initial state
   _Nop();
   SCK=1;
   _Nop();
   DATA=0;
   _Nop();
   SCK=0;  
   _Nop();//_Nop();_Nop();             //修改
   SCK=1;
   _Nop();
   DATA=1;		   
   _Nop();
   SCK=0;		   
}

//----------------------------------------------------------------------------------
void s_connectionreset(void)
//----------------------------------------------------------------------------------
// communication reset: DATA-line=1 and at least 9 SCK cycles followed by transstart
//       _____________________________________________________         ________
// DATA:                                                      |_______|
//          _    _    _    _    _    _    _    _    _        ___     ___
// SCK : __| |__| |__| |__| |__| |__| |__| |__| |__| |______|   |___|   |______
{  
  unsigned char i; 
  DATA=1; SCK=0;                    //Initial state
  for(i=0;i<9;i++)                  //9 SCK cycles
  { 
  	 SCK=1;
  	_Nop();//_Nop();               
     SCK=0;
    _Nop();//_Nop();
  }
  s_transstart();                   //transmission start
}

/*
//----------------------------------------------------------------------------------
char s_read_statusreg(unsigned char *p_value, unsigned char *p_checksum)
//----------------------------------------------------------------------------------
// reads the status register with checksum (8-bit)
{ 
  unsigned char error=0;
  s_transstart();                   //transmission start
  error=s_write_byte(STATUS_REG_R); //send command to sensor
  *p_value=s_read_byte(ACK);        //read status register (8-bit)
  *p_checksum=s_read_byte(noACK);   //read checksum (8-bit) 
    Prints("status=");
    Puthexbyte(*p_value);
    Prints("\r\n"); 
  return error;                     //error=1 in case of no response form the sensor
}

//----------------------------------------------------------------------------------
char s_write_statusreg(unsigned char *p_value)