bme280.hpp

/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2016 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 <mraa/spi.hpp>
#include <mraa/gpio.hpp>

#include "upm/iHumiditySensor.hpp"

#include "bmp280.hpp"

#define BME280_DEFAULT_I2C_BUS 0
#define BME280_DEFAULT_SPI_BUS 0
#define BME280_DEFAULT_ADDR 0x77
#define BME280_DEFAULT_CHIPID 0x60

namespace upm {

  class BME280 : public BMP280, public IHumiditySensor {
  public:

    typedef enum : uint8_t {
      // Do not write into reserved bits.

      // We only specify those registers specific to the BME280.  The
      // rest of them can be found in the BMP280 header file.

      // read-only factory calibration data for humidity
      
      REG_CALIB_DIG_H1                 = 0xa1,

      REG_CALIB_DIG_H2_LSB             = 0xe1,
      REG_CALIB_DIG_H2_MSB             = 0xe2,

      REG_CALIB_DIG_H3                 = 0xe3,

      REG_CALIB_DIG_H4_0               = 0xe4, // bits 8 -> 11:4
      REG_CALIB_DIG_H4_1               = 0xe5, // bits 3:0 -> 3:0

      REG_CALIB_DIG_H5_0               = 0xe5, // bits 7:4 -> 3:0
      REG_CALIB_DIG_H5_1               = 0xe6, // bits 8 -> 11:4

      REG_CALIB_DIG_H6                 = 0xe7,

      REG_CTRL_HUM                     = 0xf2,

      REG_HUMIDITY_MSB                 = 0xfd,
      REG_HUMIDITY_LSB                 = 0xfe
    } BME280_REGS_T;

    typedef enum {
      CTRL_HUM_OSRS_H0                 = 0x01,
      CTRL_HUM_OSRS_H1                 = 0x02,
      CTRL_HUM_OSRS_H2                 = 0x04,
      _CTRL_HUM_OSRS_H_MASK            = 3,
      _CTRL_HUM_OSRS_H_SHIFT           = 0

      // 0x08-0x80 reserved
    } CTRL_HUM_T;

    typedef enum {
      OSRS_H_SKIPPED                   = 0,
      OSRS_H_OVERSAMPLING_1            = 1, // x1
      OSRS_H_OVERSAMPLING_2            = 2, // x2
      OSRS_H_OVERSAMPLING_4            = 3,
      OSRS_H_OVERSAMPLING_8            = 4,
      OSRS_H_OVERSAMPLING_16           = 5
    } OSRS_H_T;


    BME280(int bus=BME280_DEFAULT_I2C_BUS, int addr=BME280_DEFAULT_ADDR,
           int cs=-1, uint8_t theChipID=BME280_DEFAULT_CHIPID);

    virtual ~BME280();

    virtual void update();

    float getHumidity();

    virtual void setUsageMode(USAGE_MODE_T mode);

    void setOversampleRateHumidity(OSRS_H_T rate);

    // Interface support
    const char *getModuleName()
    {
      return "BME280";
    };
    
    int getHumidityRelative()
    {
      return int(getHumidity());
    };
    
  protected:
    // relative humidity
    float m_humidity;

    // read the calibration data
    virtual void readCalibrationData();

  private:
    // calibration data humidity
    uint8_t m_dig_H1;
    int16_t m_dig_H2;
    uint8_t m_dig_H3;
    int16_t m_dig_H4;
    int16_t m_dig_H5;
    int8_t m_dig_H6;

    // Bosch supplied conversion/compensation functions from the
    // datasheet.
    uint32_t bme280_compensate_H_int32(int32_t adc_H);
  };
}