Diff: HMC5883L.h

Revision:

0:9a1682a09c50

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+++ b/HMC5883L.h	Wed Jul 17 18:50:28 2013 +0000
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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(int16_t 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