public:

/**

* As stated in datasheet (P11), the I2C address of the compass is of 7 bits and is 0x1E. The mbed API uses 8 bit addresses,

* so we need to make sure to left-shift 7 bit address by 1 bit before passing the address.

* 0x1E << 1 = 0x3C

*/

static const int I2C_ADDRESS = 0x3C;

/**

* Constructor that accepts external i2c interface and interrupt input objects

*

* Calls init function

*

* @param i2c The I2C interface object to use.

* @param drdy The digital input object to use

*/

HMC5883L(I2C &i2c, InterruptIn &drdy);

/**

* Destructor

*/

~HMC5883L();

/**

* Function for retrieving the contents of configuration register A

*

* @returns Configuration Register A

*/

int8_t getConfigurationA();

/**

* Function for retrieving the contents of configuration register B

*

* @returns Configuration Register B

*/

int8_t getConfigurationB();

/**

* Function for retrieving the contents of mode register

*

* @returns mode register

*/

int8_t getMode();

/**

* Function for retrieving the raw data

* Caution!! the HMC5883L gives the data in XZY order

*

* @param output buffer that is at least 3 in length

*/

rtStatus_t getRawXZY(int16_t raw[3]);

/**

* Function for getting radian heading using 2-dimensional calculation.

*

* Note: Compass must be held flat and away from any magnetic field generating

* devices such as cell phones and speakers.

*

* @returns XY heading in radians

*/

double getHeadingXY();

/**

* Function for getting radian heading using 2-dimensional calculation.

*

* @returns YZ heading in radians

*/

double getHeadingYZ();

/**

* Function for getting radian heading using 2-dimensional calculation.

*

* @returns ZX heading in radians

*/

double getHeadingZX();

/**

* Function for getting degree heading using 2-dimensional calculation.

*

* Note: Compass must be held flat and away from an magnetic field generating

* devices such as cell phones and speakers.

*

* @returns XY heading in degrees

*/

double getHeadingXYDeg() {

return CONVERT_RAD_TO_DEG(getHeadingXY());

}

/**

* Function for getting degree heading using 2-dimensional calculation.

*

* @returns YZ heading in degrees

*/

double getHeadingYZDeg() {

return CONVERT_RAD_TO_DEG(getHeadingYZ());

}

/**

* Function for getting degree heading using 2-dimensional calculation.

*

* @returns ZX heading in degrees

*/

double getHeadingZXDeg() {

return CONVERT_RAD_TO_DEG(getHeadingZX());

}

int8_t getDataOutputRate() const {

return m_data_output_rate;

}

void setDataOutputRate(int8_t dataOutputRate) {

m_data_output_rate = dataOutputRate;

}

int8_t getGain() const {

return m_gain;

}

void setGain(int8_t gain) {

m_gain = gain;

}

int_t getI2cSpeed() const {

return m_i2c_speed;

}

void setI2cSpeed(int_t i2cSpeed) {

m_i2c_speed = i2cSpeed;

}

int8_t getAveragingMode() const {

return m_averaging_mode;

}

void setAveragingMode(int8_t averagingMode) {

m_averaging_mode = averagingMode;

}

/**

* Function for setting up the compass.

*/

rtStatus_t setUp();

/**

* States whether the compass is working properly or not;

*/

bool isWorkingProperly() {

return m_current_state != COMPASS_FAILURE;

}

/**

* States whether the compass is stopped;

*/

bool isStopped() {

return m_current_state == COMPASS_IDLE;

}

/**

* States whether the compass is running;

*/

bool isRunning() {

return m_current_state == COMPASS_MEASURING

|| m_current_state == COMPASS_SELF_TESTING;

}

/**

* Resets the compass to default configuration.

*/

rtStatus_t reset();

/**

* Verifies that compass is healthy by performing a self test.

*/

rtStatus_t verify();

/**

* Makes the compass run i.e. measurements are performed and can be retrieved using getRawXZY() or getHeading... methods

*/

rtStatus_t run();

/**

* Stops the compass, i.e. puts it into idle mode.

*/

rtStatus_t stop();

private:

Semaphore m_semaphore;

Mutex m_mutex;

Thread m_thread;

I2C &p_i2c;

InterruptIn &p_drdy;

bool volatile m_stop_measurements;

bool volatile m_measurements_have_started;

char m_measurement_data[6];

eCompassState_t m_current_state;

int_t m_i2c_speed;

int8_t m_gain;

int8_t m_data_output_rate;

int8_t m_averaging_mode;

rtStatus_t configureForMeasurements();

rtStatus_t configureForSelfTest();

static void release(void const *argument);

static void measure(void const *argument);

static void test(void const *argument);

void initialise();

rtStatus_t performMeasurement();

rtStatus_t runMeasurements();

rtStatus_t startMeasurements();

rtStatus_t startSelfTest();

rtStatus_t stopMeasurements();

rtStatus_t executeStateMachine(eCompassState_t nextState);

rtStatus_t runSelfTest();

rtStatus_t performFullSelfTest();

rtStatus_t runSingleMeasurement();

rtStatus_t checkRawOutput(int16_t output[3]);

rtStatus_t checkLimits(int16_t output[3], int16_t limit_low,

int16_t limit_high);

rtStatus_t checkLimits(int16_t output[3]);

rtStatus_t setConfigurationRegister(int8_t register_address, int8_t value);

int8_t getConfigurationRegister(int8_t register_address);

/**

* Function for setting configuration register A

*

* Default value is 8 average Sample per output, 15Hz Data output rate, normal measurement mode

*

* @param config the value to place in Configuration Register A

*/

rtStatus_t setConfigurationA(int8_t value);

/**

* Sets the frequency of I2C

* @param frequency COMPASS_I2C_STANDARD_MODE or COMPASS_I2C_FAST_MODE

*/

rtStatus_t setI2CSpeedMode(int_t frequency);

/**

* Function for setting configuration register B

*

* Configuration Register B is for setting the device gain.

*

* @param config the value to place in Configuration Register B

*/

rtStatus_t setConfigurationB(int8_t value);

/**

* Function for setting the mode register

*

* @param mode the value for setting in the Mode Register

*/

rtStatus_t setMode(int8_t mode);

/**

* Function for retrieving the contents of status register

*

* Bit1: LOCK, Bit0: RDY

*

* @returns status register

*/

uint8_t getStatus();

/**

* Function to get a generic heading. Specify index1 and index2 to define which plane to consider e.g. for XY index1=0 index2=2 and for XZ index1=0 index2=1

*/

double getHeading(int index1, int index2);