零知开源分享-温湿度模块 SHT3X SHT30 SHT31 SHT35

#include "HTU3X.h"

 

#define LED1        PA8

 

//Create an instance of the object

HTU3X myHumidity;

 

void setup()

{

  Serial.begin(9600);

  Serial.println("HTU21D Example!");

 

        pinMode(LED1, OUTPUT);

 

  myHumidity.begin();

}

 

void loop()

{

        digitalWrite(LED1, HIGH);

        delay(500);

        digitalWrite(LED1, LOW);

         

  float humd, temp;

  myHumidity.readTempAndHumi(&temp, &humd);

 

  Serial.print("时间:");

  Serial.print(millis());

  Serial.print(" 温度:");

  Serial.print(temp, 1);

  Serial.print(" °C");

  Serial.print(" 湿度:"); 

  Serial.print(humd, 1);

  Serial.print("%");

 

  Serial.println();

  delay(1000);

}

/**

*   file : HTU3X.H

*/

 

#if defined(ARDUINO) && ARDUINO >= 100

#include "Arduino.h"

#else

#include "WProgram.h"

#endif

 

#include <SoftWire.h>

 

#define HTU3X_ADDR 0x44  //Unshifted 7-bit I2C address for the sensor

 

#define ERROR_I2C_TIMEOUT         2

#define ERROR_BAD_CRC                    3

 

#define CMD_MEAS_PERI_2_H   0x2236

#define CMD_MEAS_CLOCKSTR_H 0x2C06

 

class HTU3X {

 

public:

  HTU3X();

 

  //Public Functions

  void begin(SoftWire &wirePort = Wire); //If user doesn't specificy then Wire will be used

  byte readTempAndHumi(float *temp, float *humi);

 

  //Public Variables

 

private:

  //Private Functions

  SoftWire *_i2cPort; //The generic connection to user's chosen I2C hardware

 

  byte checkCRC(uint16_t message_from_sensor, uint8_t check_value_from_sensor);

  byte readValue(uint16_t *res);

 

  //Private Variables

 

};

/**

*   file : HTU3X.cpp

*/

#include "HTU3X.h"

 

HTU3X::HTU3X()

{

  //Set initial values for private vars

}

 

//Begin

/*******************************************************************************************/

//Start I2C communication

void HTU3X::begin(SoftWire &wirePort)

{

  _i2cPort = &wirePort; //Grab which port the user wants us to use

   

  _i2cPort->begin();

}

 

#define MAX_WAIT 100

#define DELAY_INTERVAL 10

#define MAX_COUNTER (MAX_WAIT/DELAY_INTERVAL)

 

//read 2-byte value with CRC from the HTU3X

byte HTU3X::readValue(uint16_t *res)

{

 

  byte msb, lsb, checksum;

 

  msb = _i2cPort->read();

  lsb = _i2cPort->read();

  checksum = _i2cPort->read();

 

  uint16_t rawValue = ((uint16_t) msb << 8) | (uint16_t) lsb;

 

  if (checkCRC(rawValue, checksum) != 0) 

    return (ERROR_BAD_CRC); //Error out

 

  *res = rawValue;

 

  return true;

}

 

byte HTU3X::readTempAndHumi(float *temp, float *humi)

{

    //Request a humidity reading

  _i2cPort->beginTransmission(HTU3X_ADDR);

  uint16_t cmd = CMD_MEAS_CLOCKSTR_H;

  _i2cPort->write(cmd>>8); //Measure value (prefer no hold!)

  _i2cPort->write(cmd);

  _i2cPort->endTransmission();

   

  delay(500);

 

  _i2cPort->requestFrom(HTU3X_ADDR,6);

 

  uint16_t rawTemp, rawHumi;

  readValue(&rawTemp);

  readValue(&rawHumi);

 

  _i2cPort->endTransmission();

 

  *temp = 175.0f * (float)rawTemp / 65535.0f - 45.0f; 

  *humi = 100.0f * (float)rawHumi / 65535.0f; 

 

}

  

#define SHIFTED_DIVISOR 0x988000 //This is the 0x0131 polynomial shifted to farthest left of three bytes

 

byte HTU3X::checkCRC(uint16_t message_from_sensor, uint8_t check_value_from_sensor)

{

  uint8_t bit;        

  uint8_t crc = 0xFF;

  uint8_t byteCtr;   

   uint8_t data[2] = {message_from_sensor>>8, (uint8_t)message_from_sensor};

  for(byteCtr = 0; byteCtr < 2; byteCtr++)

  {

          crc ^= (data[byteCtr]);

          for(bit = 8; bit > 0; --bit)

          {

                  if(crc & 0x80)

                          crc = (crc << 1) ^ 0x131;

                  else          

                          crc = (crc << 1);

          }

  }

    

  if(crc != check_value_from_sensor)

          return 1;

  else                               

          return 0; 

}