htu21d.hpp

/*
 * Author: William Penner <william.penner@intel.com>
 * Copyright (c) 2014 Intel Corporation.
 *
 * 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.
 */

#pragma once

#include <string>
#include <mraa/i2c.hpp>
#include <math.h>

#define HTU21D_NAME "htu21d"
#define HTU21D_I2C_ADDRESS 0x40

/* HTU21D Commands */
#define HTU21D_READ_TEMP_HOLD     0xE3
#define HTU21D_READ_HUMIDITY_HOLD 0xE5
#define HTU21D_WRITE_USER_REG     0xE6
#define HTU21D_READ_USER_REG      0xE7
#define HTU21D_SOFT_RESET         0xFE

/* User Register Bit Definition */
#define HTU21D_DISABLE_OTP        0x02
#define HTU21D_HEATER_ENABLE      0x04
#define HTU21D_END_OF_BATTERY     0x40
#define HTU21D_RESO_RH12_T14      0x00
#define HTU21D_RESO_RH8_T12       0x01
#define HTU21D_RESO_RH10_T13      0x80
#define HTU21D_RESO_RH11_T11      0x81

namespace upm {

class HTU21D {
    public:
        HTU21D (int bus, int devAddr=HTU21D_I2C_ADDRESS);

        int sampleData(void);

        float getHumidity(int bSampleData = false);

        float getTemperature(int bSampleData = false);

        float getCompRH(int bSampleData = false);

        float getDewPoint(int bSampleData = false);

        int getHumidityData(float* fHum, float* fHumTemp, float* fDewPt);

         int setHeater(int bEnable = false);

        void resetSensor(void);

        int testSensor(void);

        mraa::Result i2cWriteReg (uint8_t reg, uint8_t value);

        uint16_t i2cReadReg_16 (int reg);

        uint8_t i2cReadReg_8 (int reg);

    private:

        int32_t convertTemp(int32_t regval);

        int32_t convertRH(int32_t regval);

        std::string m_name;

        int m_controlAddr;
        int m_bus;
        mraa::I2c m_i2ControlCtx;

        int32_t m_temperature;
        int32_t m_humidity;
};

}