File content as of revision 0:9b2a0b783bfc:

#include "LSM303DLH.h"
#include "Vector.h"

const char SAD_ACC = 0x30;
const char SAD_MAG = 0x3C;
const float ACC_UNIT[] = {0.001, 0.002, 0,  0.0039};
const float MAG_UNIT_XY[] = {0, 1.0 / 1055, 1.0 / 795, 1.0 / 635, 1.0 / 430, 1.0 / 375, 1.0 / 320, 1.0 / 230};
const float MAG_UNIT_Z[] = {0, 1.0 / 950, 1.0 / 710, 1.0 / 570, 1.0 / 385, 1.0 / 335, 1.0 / 285, 1.0 / 205};

enum REG_ADDRS {
    CRA_REG_M         = 0x00,
    CRB_REG_M         = 0x01,
    MR_REG_M          = 0x02,
    OUT_X_H_M         = 0x03,
    OUT_X_L_M         = 0x04,
    OUT_Y_H_M         = 0x05,
    OUT_Y_L_M         = 0x06,
    OUT_Z_H_M         = 0x07,
    OUT_Z_L_M         = 0x08,
    SR_REG_M          = 0x09,
    IRA_REG_M         = 0x0A,
    IRB_REG_M         = 0x0B,
    IRC_REG_M         = 0x0C,

    CTRL_REG1_A       = 0x20,
    CTRL_REG2_A       = 0x21,
    CTRL_REG3_A       = 0x22,
    CTRL_REG4_A       = 0x23,
    CTRL_REG5_A       = 0x24,
    HP_FILTER_RESET_A = 0x25,
    REFERENCE_A       = 0x26,
    STATUS_REG_A      = 0x27,
    OUT_X_L_A         = 0x28,
    OUT_X_H_A         = 0x29,
    OUT_Y_L_A         = 0x2A,
    OUT_Y_H_A         = 0x2B,
    OUT_Z_L_A         = 0x2C,
    OUT_Z_H_A         = 0x2D,

    INT1_CFG_A        = 0x30,
    INT1_SOURCE_A     = 0x31,
    INT1_THS_A        = 0x32,
    INT1_DURATION_A   = 0x33,
    INT2_CFG_A        = 0x34,
    INT2_SOURCE_A     = 0x35,
    INT2_THS_A        = 0x36,
    INT2_DURATION_A   = 0x37,
};

LSM303DLH::LSM303DLH(PinName sda, PinName scl, PinName int1, PinName int2)
        : ax(0), ay(0), az(0), mx(0), my(0), mz(0),
        i2c(sda, scl), acc_range(ACC_RANGE_2G), mag_range(MAG_RANGE_1_3GAUSS),
        int1(int1), int2(int2) {
    send(SAD_ACC, CTRL_REG1_A, 0x27); // output rate 400 Hz
    send(SAD_ACC, CTRL_REG4_A, 0xC0); // block data update; big endian, max=2g
    send(SAD_MAG, CRA_REG_M, 0x18); // min data output rate 75Hz
    send(SAD_MAG, MR_REG_M, 0x00); // continuous conversion mode
}

bool LSM303DLH::setOutputDataRate(ACC_ODR acc_odr, MAG_ODR mag_odr) {
    return send(SAD_ACC, CTRL_REG4_A, 0x27 | acc_odr << 3) &&
           send(SAD_MAG, CRA_REG_M, mag_odr << 2);
}

bool LSM303DLH::setMeasurementRange(ACC_RANGE acc_range, MAG_RANGE mag_range) {
    this->acc_range = acc_range;
    this->mag_range = mag_range;

    return send(SAD_ACC, CTRL_REG4_A, 0xC0 | acc_range << 4) &&
           send(SAD_MAG, CRB_REG_M, mag_range << 5);
}

bool LSM303DLH::read() {
    char acc[6], mag[6];

    if (recv(0x30, OUT_X_L_A, acc, 6) && recv(0x3C, OUT_X_H_M, mag, 6)) {
        ax = ACC_UNIT[acc_range] * short(acc[0] << 8 | acc[1]) / 16;
        ay = ACC_UNIT[acc_range] * short(acc[2] << 8 | acc[3]) / 16;
        az = ACC_UNIT[acc_range] * short(acc[4] << 8 | acc[5]) / 16;
        mx = MAG_UNIT_XY[mag_range] * short(mag[0] << 8 | mag[1]);
        my = MAG_UNIT_XY[mag_range] * short(mag[2] << 8 | mag[3]);
        mz = MAG_UNIT_Z[mag_range] * short(mag[4] << 8 | mag[5]);

        return true;
    }

    return false;
}

bool LSM303DLH::read(float *ax, float *ay, float *az, float *mx, float *my, float *mz) {
    if (ax != 0 || ay != 0 || az != 0) {
        char acc[6];

        if (recv(0x30, OUT_X_L_A, acc, 6)) {
            if (ax != 0) *ax = ACC_UNIT[acc_range] * short(acc[0] << 8 | acc[1]) / 16;
            if (ay != 0) *ay = ACC_UNIT[acc_range] * short(acc[2] << 8 | acc[3]) / 16;
            if (az != 0) *az = ACC_UNIT[acc_range] * short(acc[4] << 8 | acc[5]) / 16;
        } else
            return false;
    }

    if (mx != 0 || my != 0 || mz != 0) {
        char mag[6];

        if (recv(0x3C, OUT_X_H_M, mag, 6)) {
            if (mx != 0) *mx = MAG_UNIT_XY[mag_range] * short(mag[0] << 8 | mag[1]);
            if (my != 0) *my = MAG_UNIT_XY[mag_range] * short(mag[2] << 8 | mag[3]);
            if (mz != 0) *mz = MAG_UNIT_Z[mag_range] * short(mag[4] << 8 | mag[5]);
        } else
            return false;
    }

    return true;
}

float LSM303DLH::getHeading() {
    return getHeading(0, 1, 0);
}

float LSM303DLH::getHeading(float x, float y, float z) {
    Vector base(x, y, z);
    Vector accel = Vector(ax, ay, az);
    Vector compass = Vector(mx, my, mz);
    Vector east = compass * accel;
    Vector north = accel * east;
    east /= east.norm();
    north /= north.norm();
    //printf("accel = (%.1f, %.1f, %.1f), compass = (%.1f, %.1f, %.1f)\n", accel.x, accel.y, accel.z, compass.x, compass.y, compass.z);
    //printf("north = (%.1f, %.1f, %.1f), east = (%.1f, %.1f, %.1f)\n", north.x, north.y, north.z, east.x, east.y, east.z);
    //printf("east.dot(base) = %.1f, north.dot(base) = %.1f\n", east.dot(base), north.dot(base));

    return atan2(east.dot(base), north.dot(base));
}

void LSM303DLH::attach(INT_TYPE type, char config, char threshold, char duration, void (*handler)(void)) {
    InterruptIn& interruptIn = (type == INT1) ? int1 : int2;
    send(SAD_ACC, type == INT1 ? INT1_CFG_A : INT2_CFG_A, config);
    send(SAD_ACC, type == INT1 ? INT1_THS_A : INT2_THS_A, threshold);
    send(SAD_ACC, type == INT1 ? INT1_DURATION_A : INT2_DURATION_A, duration);
    interruptIn.rise(handler);
}

template<typename T> void LSM303DLH::attach(T *t, INT_TYPE type, char config, char threshold, char duration, void (*handler)(void)) {
    InterruptIn& interruptIn = (type == INT1) ? int1 : int2;
    interruptIn.rise(t, handler);
}

bool LSM303DLH::recv(char sad, char sub, char *buf, int length) {
    if (length > 1) sub |= 0x80;

    return i2c.write(sad, &sub, 1, true) == 0 && i2c.read(sad, buf, length) == 0;
}

bool LSM303DLH::send(char sad, char sub, char data) {
    char buf[] = {sub, data};

    return i2c.write(sad, buf, 2) == 0;
}