MAG3110.h

00001 /*
00002  * MAG3110 Sensor Library for mbed
00003  * TODO: Add proper header
00004  */
00005 
00006 #ifndef MAG3110_H
00007 #define MAG3110_H
00008 
00009 #include "mbed.h"
00010 
00011 #define PI 3.14159265359
00012 
00013 #define MAG_ADDR 0x1D
00014 
00015 // define registers
00016 #define MAG_DR_STATUS 0x00
00017 #define MAG_OUT_X_MSB 0x01
00018 #define MAG_OUT_X_LSB 0x02
00019 #define MAG_OUT_Y_MSB 0x03
00020 #define MAG_OUT_Y_LSB 0x04
00021 #define MAG_OUT_Z_MSB 0x05
00022 #define MAG_OUT_Z_LSB 0x06
00023 #define MAG_WHO_AM_I  0x07
00024 #define MAG_SYSMOD    0x08
00025 #define MAG_OFF_X_MSB 0x09
00026 #define MAG_OFF_X_LSB 0x0A
00027 #define MAG_OFF_Y_MSB 0x0B
00028 #define MAG_OFF_Y_LSB 0x0C
00029 #define MAG_OFF_Z_MSB 0x0D
00030 #define MAG_OFF_Z_LSB 0x0E
00031 #define MAG_DIE_TEMP  0x0F
00032 #define MAG_CTRL_REG1 0x10
00033 #define MAG_CTRL_REG2 0x11
00034 
00035 // what should WHO_AM_I return?
00036 #define MAG_3110_WHO_AM_I_VALUE 0xC4
00037 
00038 
00039 // Fields in registers
00040 // CTRL_REG1: dr2,dr1,dr0  os1,os0  fr tm ac
00041 
00042 // Sampling rate from 80Hz down to 0.625Hz
00043 #define MAG_3110_SAMPLE80 0
00044 #define MAG_3110_SAMPLE40 0x20
00045 #define MAG_3110_SAMPLE20 0x40
00046 #define MAG_3110_SAMPLE10 0x60
00047 #define MAG_3110_SAMPLE5 0x80
00048 #define MAG_3110_SAMPLE2_5 0xA0
00049 #define MAG_3110_SAMPLE1_25 0xC0
00050 #define MAG_3110_SAMPLE0_625 0xE0
00051 
00052 // How many samples to average (lowers data rate)
00053 #define MAG_3110_OVERSAMPLE1 0
00054 #define MAG_3110_OVERSAMPLE2 0x08
00055 #define MAG_3110_OVERSAMPLE3 0x10
00056 #define MAG_3110_OVERSAMPLE4 0x18
00057 
00058 // read only 1 byte per axis
00059 #define MAG_3110_FASTREAD 0x04
00060 // do one measurement (even if in standby mode)
00061 #define MAG_3110_TRIGGER 0x02
00062 // put in active mode
00063 #define MAG_3110_ACTIVE 0x01
00064 
00065 // CTRL_REG2: AUTO_MRST_EN  _ RAW MAG_RST _ _ _ _ _
00066 // reset sensor after each reading
00067 #define MAG_3110_AUTO_MRST_EN 0x80
00068 // don't subtract user offsets
00069 #define MAG_3110_RAW 0x20
00070 // reset magnetic sensor after too-large field
00071 #define MAG_3110_MAG_RST 0x10
00072 
00073 // DR_STATUS Register ZYXOW ZOW YOW XOW ZYXDR ZDR YDR XDR
00074 #define MAG_3110_ZYXDR  0x08
00075 
00076 /**
00077  * MAG3110 Class to read X/Y/Z data from the magentometer
00078  *
00079  */
00080 class MAG3110
00081 {
00082 public:
00083     /**
00084      * Main constructor
00085      * @param sda SDA pin
00086      * @param sdl SCL pin
00087      * @param addr addr of the I2C peripheral
00088      */
00089     MAG3110(PinName sda, PinName scl);
00090     /**
00091      * Debug version of constructor
00092      * @param sda SDA pin
00093      * @param sdl SCL pin
00094      * @param addr Address of the I2C peripheral
00095      * @param pc Serial object to output debug messages
00096      */
00097     MAG3110(PinName sda, PinName scl, Serial *pc); //pass serial for debug
00098     /**
00099      * Setup the Magnetometer
00100      *
00101      */
00102     void begin();
00103     /**
00104      * Read a register, return its value as int
00105      * @param regAddr The address to read
00106      * @return value in register
00107      */
00108     int readReg(char regAddr);
00109     /**
00110      * Read a value from a pair of registers, return as int
00111      * @param regAddr The address to read
00112      * @return Value from 2 consecutive registers
00113      */
00114     int readVal(char regAddr);
00115     /**
00116      * Calculate the heading
00117      * @return heading in degrees
00118      */
00119     float getHeading();
00120     /**
00121      * Perform a read on the X, Y and Z values.
00122      * @param xVal Pointer to X value
00123      * @param yVal Pointer to Y value
00124      * @param zVal Pointer to Z value
00125      */
00126     void getValues(int *xVal, int *yVal, int *zVal);
00127     /**
00128      * Set the calibration parameters if required.
00129      * @param minX Minimum value for X range
00130      * @param maxX Maximum value for X range
00131      * @param minY Minimum value for Y range
00132      * @param maxY maximum value for Y range
00133      */
00134     void setCalibration(int minX, int maxX, int minY, int maxY);
00135 
00136 private:
00137     I2C _i2c;
00138     int _i2c_address;
00139     Serial *_pc;
00140     bool _debug;
00141     int _avgX, _avgY;
00142 
00143 };
00144 #endif