sht10.c

sht10驱动程序

/***********************************************************************************
Project:          SHTxx demo program (V2.1)
Filename:         SHTxx_Sample_Code.c    

Prozessor:        80C51 family
Compiler:         Keil Version 6.14

Autor:            MST
Copyrigth:        (c) Sensirion AG      
***********************************************************************************/

#include "stc89c52.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
#include "sht10.h"
#include "main.h"
#include "i2c.h"
#include "beep.h"
#include "relay.h"
#include "12232.h"


char s_write_byte(unsigned char value)

{ 
  unsigned char i,error=0;  
  for (i=0x80;i>0;i/=2)             //shift bit for masking
  { 
    if(i&value) 
     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;
  }
  DATA=1;                           //release DATA-line
  SCK=1;                            //clk #9 for ack 
  error=DATA;                       //check ack (DATA will be pulled down by SHT11)
  SCK=0;        
  return error;                     //error=1 in case of no acknowledge
}


char s_read_byte(unsigned char ack)

{ 
  unsigned char 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
    if (DATA) val=(val | i);        //read bit  
    SCK=0;  					 
  }
  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;						    
  DATA=1;                           //release DATA-line
  return val;
}


void s_transstart(void)

{  
   DATA=1; SCK=0;                   //Initial state
   _nop_();
   SCK=1;
   _nop_();
   DATA=0;
   _nop_();
   SCK=0;  
   _nop_();_nop_();_nop_();
   SCK=1;
   _nop_();
   DATA=1;		   
   _nop_();
   SCK=0;		   
}

void s_connectionreset(void)

{  
  unsigned char i; 
  DATA=1; SCK=0;                    //Initial state
  for(i=0;i<9;i++)                  //9 SCK cycles
  { SCK=1;
    SCK=0;
  }
  s_transstart();                   //transmission start
}


char s_softreset(void)

{ 
  unsigned char error=0;  
  s_connectionreset();              //reset communication
  error+=s_write_byte(RESETsht10);       //send RESET-command to sensor
  return error;                     //error=1 in case of no response form the sensor
}


char s_read_statusreg(unsigned char *p_value, unsigned char *p_checksum)
{ 
  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)  
  return error;                     //error=1 in case of no response form the sensor
}


char s_write_statusreg(unsigned char *p_value)
{ 
  unsigned char error=0;
  s_transstart();                   //transmission start
  error+=s_write_byte(STATUS_REG_W);//send command to sensor
  error+=s_write_byte(*p_value);    //send value of status register
  return error;                     //error>=1 in case of no response form the sensor
}
 							   

char s_measure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode)
{ 
  unsigned error=0;
  unsigned int i;

  s_transstart();                   //transmission start
  switch(mode){                     //send command to sensor
    case TEMP	: error+=s_write_byte(MEASURE_TEMP); break;
    case HUMI	: error+=s_write_byte(MEASURE_HUMI); break;
    default     : break;	 
  }
  for (i=0;i<65535;i++) if(DATA==0) break; //wait until sensor has finished the measurement
  if(DATA) error+=1;                // or timeout (~2 sec.) is reached
  *(p_value)  =s_read_byte(ACK);    //read the first byte (MSB)
  *(p_value+1)=s_read_byte(ACK);    //read the second byte (LSB)
  *p_checksum =s_read_byte(noACK);  //read checksum
  return error;
}

void calc_sth11(float *p_humidity ,float *p_temperature)
{ const float C1=-4.0;              // for 12 Bit
  const float C2=+0.0405;           // for 12 Bit
  const float C3=-0.0000028;        // for 12 Bit
  const float T1=+0.01;             // for 14 Bit @ 5V
  const float T2=+0.00008;           // for 14 Bit @ 5V	

  float rh=*p_humidity;             // rh:      Humidity [Ticks] 12 Bit 
  float t=*p_temperature;           // t:       Temperature [Ticks] 14 Bit
  float rh_lin;                     // rh_lin:  Humidity linear
  float rh_true;                    // rh_true: Temperature compensated humidity
  float t_C;                        // t_C   :  Temperature [癈]

  t_C=t*0.01 - 40;                  //calc. temperature from ticks to [癈]
  rh_lin=C3*rh*rh + C2*rh + C1;     //calc. humidity from ticks to [%RH]
  rh_true=(t_C-25)*(T1+T2*rh)+rh_lin;   //calc. temperature compensated humidity [%RH]
  if(rh_true>100)rh_true=100;       //cut if the value is outside of
  if(rh_true<0.1)rh_true=0.1;       //the physical possible range

  *p_temperature=t_C;               //return temperature [癈]
  *p_humidity=rh_true;              //return humidity[%RH]
}


float calc_dewpoint(float h,float t)
{ float logEx,dew_point;
  logEx=0.66077+7.5*t/(237.3+t)+(log10(h)-2);
  dew_point = (logEx - 0.66077)*237.3/(0.66077+7.5-logEx);
  return dew_point;
}


void mainsht10()
{ value humi_val,temp_val;
  float dew_point;
  unsigned char error,checksum;
  s_connectionreset();
    error=0;
    error+=s_measure((unsigned char*) &humi_val.i,&checksum,HUMI);  //measure humidity
    error+=s_measure((unsigned char*) &temp_val.i,&checksum,TEMP);  //measure temperature
    if(error!=0) 
    { 
       
        s_connectionreset();                 //in case of an error: connection reset
        beepone(1,500,1);

    }
     else
    { 

      humi_val.f=(float)humi_val.i;                   //converts integer to float
      temp_val.f=(float)temp_val.i;                   //converts integer to float

      calc_sth11(&humi_val.f,&temp_val.f);            //calculate humidity, temperature
      dew_point=calc_dewpoint(humi_val.f,temp_val.f); //calculate dew point
      
      NowT[0]=(int)temp_val.f;NowH[0]=(int)humi_val.f;
      sprintf(NO2R,"%02dC     %02d%%",(int)NowT[0],(int)NowH[0]);
      
    }

}