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 // Fields in registers
00039 // CTRL_REG1: dr2,dr1,dr0  os1,os0  fr tm ac
00040 
00041 // Sampling rate from 80Hz down to 0.625Hz
00042 #define MAG_3110_SAMPLE80 0
00043 #define MAG_3110_SAMPLE40 0x20
00044 #define MAG_3110_SAMPLE20 0x40
00045 #define MAG_3110_SAMPLE10 0x60
00046 #define MAG_3110_SAMPLE5 0x80
00047 #define MAG_3110_SAMPLE2_5 0xA0
00048 #define MAG_3110_SAMPLE1_25 0xC0
00049 #define MAG_3110_SAMPLE0_625 0xE0
00050 
00051 // How many samples to average (lowers data rate)
00052 #define MAG_3110_OVERSAMPLE1 0
00053 #define MAG_3110_OVERSAMPLE2 0x08
00054 #define MAG_3110_OVERSAMPLE3 0x10
00055 #define MAG_3110_OVERSAMPLE4 0x18
00056 
00057 // read only 1 byte per axis
00058 #define MAG_3110_FASTREAD 0x04
00059 // do one measurement (even if in standby mode)
00060 #define MAG_3110_TRIGGER 0x02
00061 // put in active mode
00062 #define MAG_3110_ACTIVE 0x01
00063 
00064 // CTRL_REG2: AUTO_MRST_EN  _ RAW MAG_RST _ _ _ _ _
00065 // reset sensor after each reading
00066 #define MAG_3110_AUTO_MRST_EN 0x80
00067 // don't subtract user offsets
00068 #define MAG_3110_RAW 0x20
00069 // reset magnetic sensor after too-large field
00070 #define MAG_3110_MAG_RST 0x10
00071 
00072 // DR_STATUS Register ZYXOW ZOW YOW XOW ZYXDR ZDR YDR XDR
00073 #define MAG_3110_ZYXDR  0x08
00074 
00075 /**
00076  * MAG3110 Class to read X/Y/Z data from the magentometer
00077  *
00078  */
00079 class MAG3110
00080 {
00081 public:
00082     /**
00083      * Main constructor
00084      * @param sda SDA pin
00085      * @param sdl SCL pin
00086      * @param addr addr of the I2C peripheral
00087      */
00088     MAG3110(PinName sda, PinName scl);
00089     /**
00090      * Debug version of constructor
00091      * @param sda SDA pin
00092      * @param sdl SCL pin
00093      * @param addr Address of the I2C peripheral
00094      * @param pc Serial object to output debug messages
00095      */
00096     MAG3110(PinName sda, PinName scl, Serial *pc); //pass serial for debug
00097     /**
00098      * Setup the Magnetometer
00099      *
00100      */
00101     void begin();
00102     /**
00103      * Read a register, return its value as int
00104      * @param regAddr The address to read
00105      * @return value in register
00106      */
00107     int readReg(char regAddr);
00108     /**
00109      * Read a value from a pair of registers, return as int
00110      * @param regAddr The address to read
00111      * @return Value from 2 consecutive registers
00112      */
00113     int readVal(char regAddr);
00114     /**
00115      * Calculate the heading
00116      * @return heading in degrees
00117      */
00118     float getHeading();
00119     /**
00120      * Perform a read on the X, Y and Z values.
00121      * @param xVal Pointer to X value
00122      * @param yVal Pointer to Y value
00123      * @param zVal Pointer to Z value
00124      */
00125     void getValues(int *xVal, int *yVal, int *zVal);
00126     /**
00127      * Set the calibration parameters if required.
00128      * @param minX Minimum value for X range
00129      * @param maxX Maximum value for X range
00130      * @param minY Minimum value for Y range
00131      * @param maxY maximum value for Y range
00132      */
00133     void setCalibration(int minX, int maxX, int minY, int maxY);
00134 
00135 private:
00136     I2C _i2c;
00137     int _i2c_address;
00138     Serial *_pc;
00139     bool _debug;
00140     int _avgX, _avgY;
00141 
00142 };
00143 #endif