upm/src/am2315/am2315.hpp

/*
 * Author: William Penner <william.penner@intel.com>
 * Copyright (c) 2014 Intel Corporation.
 *
 * This program and the accompanying materials are made available under the
 * terms of the The MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 */

#pragma once

#include <string>
#include <mraa/i2c.h>
#include <mraa/initio.hpp>
#include <math.h>
#include <interfaces/iHumidity.hpp>
#include <interfaces/iTemperature.hpp>


#define AM2315_NAME "am2315"
#define AM2315_I2C_ADDRESS 0x5c

#define AM2315_READ     0x03
#define AM2315_WRITE    0x10

/* AM2315 Commands */
#define AM2315_HUMIDITY 0x00
#define AM2315_TEMP     0x02
#define AM2315_MODEL    0x08
#define AM2315_VERSION  0x0A
#define AM2315_ID       0x0B
#define AM2315_STATUS   0x0F
#define AM2315_USER_A   0x10
#define AM2315_USER_B   0x12

#define AM2315_SAMPLE   2

#define HIGH_PRIORITY   99

namespace upm {

/**
 * @brief AM2315 Temperature & Humidity Sensor
 * @defgroup am2315 libupm-am2315
 * @ingroup adafruit i2c temp
 */

/**
 * @library am2315
 * @sensor am2315
 * @comname Digital Temperature and Humidity Sensor
 * @type temp
 * @man adafruit
 * @web http://www.adafruit.com/products/1293
 * @con i2c
 *
 * @brief API for the AM2315 Temperature & Humidity Sensor
 *
 * AM2315 by Measurement Specialties
 * (http://www.aosong.com/asp_bin/Products/en/AM2315.pdf)
 * is a digital humidity sensor with temperature output.
 * RH reports between 0 and 100%, and the temperature range is
 * -40 to +125 degC.
 * The sampling period of this sensor is 2 seconds. Reads occurring
 * more often than that return cached data.
 *
 * @image html am2315.jpeg
 * @snippet am2315.cxx Interesting
 */
class AM2315 : virtual public iHumidity, virtual public iTemperature {
    public:
        /**
         * Instantiates an AM2315 object
         *
         * @param bus Number of the used bus
         * @param devAddr Address of the used I2C device
         */
        AM2315 (int bus, int devAddr=AM2315_I2C_ADDRESS);

        /**
         * Instantiates AM2315 Temperature & Humidity Sensor based on a given string.
         *
         * @param initStr string containing specific information for AM2315 initialization.
         */
        AM2315 (std::string initStr);

        /**
         * AM2315 object destructor; basically, it closes the I2C connection.
         */
        ~AM2315 ();

        /**
         * Gets the current measured humidity [RH]
         *
         * Data is updated every 2 seconds - accesses occurring more often than
         * that return cached data
         */
        virtual float getHumidity(void);

        /**
         * Gets the humidity cell temperature [degC]
         *
         * Data is updated every 2 seconds - accesses occurring more often than
         * that return cached data
         *
         * @return float compensated temperature value
         */
        virtual float getTemperature(void);

        /**
         * Gets the humidity cell temperature [degF]
         *
         * Data is updated every 2 seconds - accesses occurring more often than
         * that return cached data
         */
        float getTemperatureF(void);

        /**
         * Function intended to test the device and verify it
         * is operating correctly.
         *
         */
        int testSensor(void);

        /**
         * Writes a four-byte (32b) register
         *
         * Note: these access routines are not the normal accesses to an I2C
         * device. AM2315 contains a microcontroller that manages the
         * actual readings. These handlers then make requests over I2C using
         * a protocol defined by AM2315.
         *
         * @param reg Address of the register
         * @param ival 32b value
         */
        int i2cWriteReg_32(int reg, uint32_t ival);

        /**
         * Writes a two-byte (16b) register
         *
         * @param reg Address of the register
         * @param ival 16b value
         */
        int i2cWriteReg_16(int reg, uint16_t ival);

        /**
         * Writes a one-byte (8b) register
         *
         * @param reg Address of the register
         * @param ival 8b value
         */
        int i2cWriteReg_8(int reg, uint8_t ival);

        /**
         * Reads a four-byte register
         *
         * @param reg Address of the register
         */
        uint32_t i2cReadReg_32 (int reg);

        /**
         * Reads a two-byte register
         *
         * @param reg Address of the register
         */
        uint16_t i2cReadReg_16 (int reg);

        /**
         * Reads a one-byte register
         *
         * @param reg Address of the register
         */
        uint8_t i2cReadReg_8 (int reg);

    private:

        char* m_name;

        int m_controlAddr;
        int m_bus;
        mraa_i2c_context m_i2ControlCtx;
        mraa::MraaIo mraaIo;

        void update_values(void);
        uint8_t i2cReadReg(int reg, uint8_t* data, int ilen);
        int i2cWriteReg(uint8_t reg, uint8_t* data, uint8_t ilen);
        uint16_t crc16(uint8_t* ptr, uint8_t len);

        int32_t   m_temperature;
        int32_t   m_humidity;

        uint16_t  m_model;
        uint16_t  m_version;
        uint32_t  m_id;

        time_t    m_last_time;

        int       m_base_priority;
};

}