HTU21D.h

/*
 * The MIT License (MIT)
 * Copyright (c) 2015-2017 François GUILLIER <dev @ guillier . org>
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "Arduino.h"
#include <Wire.h>

#define HTDU21D_ADDRESS 0x40  //Unshifted 7-bit I2C address for the sensor

#define TRIGGER_TEMP_MEASURE_HOLD  0xE3
#define TRIGGER_HUMD_MEASURE_HOLD  0xE5
#define TRIGGER_TEMP_MEASURE_NOHOLD  0xF3
#define TRIGGER_HUMD_MEASURE_NOHOLD  0xF5
#define WRITE_USER_REG  0xE6
#define READ_USER_REG  0xE7
#define SOFT_RESET  0xFE
#define SERIAL_NUMBER_1A  0xFA
#define SERIAL_NUMBER_1B  0x0F
#define SERIAL_NUMBER_2A  0xFC
#define SERIAL_NUMBER_2B  0xC9


class HTU21D {

public:
  HTU21D();

  //Public Functions
  boolean begin(int sda=4, int scl=5);
  boolean reset();
  float readHumidity(void);
  float readTemperature(void);
  boolean get_serial_number (byte[]);

private:
  //Private Functions

  unsigned int readValue(int);
  byte check_crc(uint16_t message_from_sensor, uint8_t check_value_from_sensor);

  //Private Variables

};