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/*
 * @file HMC5883L.h
 * @author Tyler Weaver
 *
 * @section LICENSE
 *
 * 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.
 *
 * @section DESCRIPTION
 *
 * HMC5883L 3-Axis Digital Compas IC
 * For use with the Sparkfun 9 Degrees of Freedom - Sensor Stick
 *
 * Datasheet:
 *
 * http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/Magneto/HMC5883L-FDS.pdf
 */

#ifndef HMC5883L_H
#define HMC5883L_H

#include "mbed.h"

/*
* Defines
*/

//-----------
// Registers
//-----------
#define CONFIG_A_REG    0x00
#define CONFIG_B_REG    0x01
#define MODE_REG        0x02
#define OUTPUT_REG      0x03
#define STATUS_REG      0x09

// configuration register a
#define AVG1_SAMPLES    0x00
#define AVG2_SAMPLES    0x20
#define AVG4_SAMPLES    0x80
#define AVG8_SAMPLES    0xC0

#define OUTPUT_RATE_0_75    0x00
#define OUTPUT_RATE_1_5     0x04
#define OUTPUT_RATE_3       0x08
#define OUTPUT_RATE_7_5     0x0C
#define OUTPUT_RATE_15      0x10
#define OUTPUT_RATE_30      0x14
#define OUTPUT_RATE_75      0x18

#define NORMAL_MEASUREMENT  0x00
#define POSITIVE_BIAS       0x01
#define NEGATIVE_BIAS       0x02

// mode register
#define CONTINUOUS_MODE     0x00
#define SINGLE_MODE         0x01
#define IDLE_MODE           0x02

// status register
#define STATUS_LOCK         0x02
#define STATUS_READY        0x01

// Utility
#ifndef M_PI
#define M_PI 3.1415926535897932384626433832795
#endif

#define PI2         (2*M_PI)
#define RAD_TO_DEG  (180.0/M_PI)
#define DEG_TO_RAD  (M_PI/180.0)

/**
 * The HMC5883L 3-Axis Digital Compass IC
 */
class HMC5883L
{

public:

    /**
     * The I2C address that can be passed directly to i2c object (it's already shifted 1 bit left).
     */
    static const int I2C_ADDRESS = 0x3D;

    /**
     * Constructor.
     *
     * Calls init function
     *
     * @param sda - mbed pin to use for the SDA I2C line.
     * @param scl - mbed pin to use for the SCL I2C line.
     */
    HMC5883L(PinName sda, PinName scl);

    /**
    * Constructor that accepts external i2c interface object.
    * 
    * Calls init function
    *
    * @param i2c The I2C interface object to use.
    */
    HMC5883L(I2C &i2c) : i2c_(i2c) {
        init();
    }

    ~HMC5883L();
    
    /**
    * Initalize function called by all constructors.
    * 
    * Place startup code in here.
    */
    void init();
    
    /**
    * Function for setting configuration register A
    *
    * Defined constants should be ored together to create value.
    * Defualt is 0x10 - 1 Sample per output, 15Hz Data output rate, normal measurement mode
    *
    * Refer to datasheet for instructions for setting Configuration Register A.
    *
    * @param config the value to place in Configuration Register A
    */
    void setConfigurationA(char);
    
    /**
    * Function for retrieving the contents of configuration register A
    * 
    * @returns Configuration Register A
    */
    char getConfigurationA();
    
    /**
    * Function for setting configuration register B
    *
    * Configuration Register B is for setting the device gain.
    * Default value is 0x20
    * 
    * Refer to datasheet for instructions for setting Configuration Register B
    *
    * @param config the value to place in Configuration Register B
    */
    void setConfigurationB(char);
    
    /**
    * Function for retrieving the contents of configuration register B
    * 
    * @returns Configuration Register B
    */
    char getConfigurationB();
    
    /**
    * Funciton for setting the mode register
    * 
    * Constants: CONTINUOUS_MODE, SINGLE_MODE, IDLE_MODE
    * 
    * When you send a the Single-Measurement Mode instruction to the mode register
    * a single measurement is made, the RDY bit is set in the status register,
    * and the mode is placed in idle mode.
    *
    * When in Continous-Measurement Mode the device continuously performs measurements
    * and places the results in teh data register.  After being placed in this mode
    * it takes two periods at the rate set in the data output rate before the first
    * sample is avaliable.
    *
    * Refer to datasheet for more detailed instructions for setting the mode register.
    *  
    * @param mode the value for setting in the Mode Register
    */
    void setMode(char);
    
    /**
    * Function for retrieving the contents of mode register
    * 
    * @returns mode register
    */
    char getMode();
    
    /**
    * Function for retriaval of the raw data
    *
    * @param output buffer that is atleast 3 in length
    */
    void getXYZ(int raw[3]);
    
    /**
    * Function for retrieving the contents of status register
    * 
    * Bit1: LOCK, Bit0: RDY
    *
    * @returns status register
    */
    char getStatus();
    
    /**
    * Function for getting radian heading using 2-dimensional calculation.
    * 
    * Compass must be held flat and away from an magnetic field generating
    * devices such as cell phones and speakers.
    *
    * TODO: declenation angle compensation
    * 
    * @returns heading in radians
    */
    double getHeadingXY();
    
    /**
    * Function for getting degree heading using 2-dimensional calculation.
    * 
    * Compass must be held flat and away from an magnetic field generating
    * devices such as cell phones and speakers.
    *
    * TODO: declenation angle compensation
    * 
    * @returns heading in degrees
    */
    double getHeadingXYDeg() {
        return (getHeadingXY() * RAD_TO_DEG);
    }

private:

    I2C &i2c_;

    /**
     * The raw buffer for allocating I2C object in its own without heap memory.
     */
    char i2cRaw[sizeof(I2C)];
};

#endif // HMC5883L