File content as of revision 3:9b4ff901b5c9:

/** LSM303DLH Interface Library
 *
 * Michael Shimniok http://bot-thoughts.com
 *
 * Based on test program by @tosihisa and 
 *
 * Pololu sample library for LSM303DLH breakout by ryantm:
 *
 * Copyright (c) 2011 Pololu Corporation. For more information, see
 *
 * http://www.pololu.com/
 * http://forum.pololu.com/
 *
 * 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.
 */
#include "mbed.h"
#include "LSM303DLH.h"

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#define FILTER_SHIFT 6      // used in filtering acceleromter readings

const int addr_acc = 0x32;//0x30;
const int addr_mag = 0x3c;

enum REG_ADDRS {
    /* --- Mag --- */
    CRA_REG_M   = 0x00,
    CRB_REG_M   = 0x01,
    MR_REG_M    = 0x02,
    OUT_X_M     = 0x03,
    OUT_Y_M     = 0x05,
    OUT_Z_M     = 0x07,
    /* --- Acc --- */
    CTRL_REG1_A = 0x20,
    CTRL_REG4_A = 0x23,
    STATUS_REG_A= 0x27,
    OUT_X_A     = 0x28,
    OUT_Y_A     = 0x2A,
    OUT_Z_A     = 0x2C,
};

bool LSM303DLH::write_reg(int addr_i2c,int addr_reg, char v)
{
    bool result=false;
    char data[2] = {addr_reg, v};
    //__disable_irq();
    result = m_ptr_I2C->write(addr_i2c, data, 2) == 0;
    if(result == false) debug("Unable to Write \n");
    
    //__enable_irq(); 
    return result;
}

bool LSM303DLH::read_reg(int addr_i2c,int addr_reg, char *v)
{
    char data = addr_reg; 
    bool result = false;
    
    //__disable_irq();
    if(m_ptr_I2C->write(addr_i2c, &data, 1) == 0)
    {        
        if (m_ptr_I2C->read(addr_i2c, &data, 1) == 0)
        {            
            *v = data;
            result = true;
        }
        else
        {
            debug("Unable to Read \n");
        }
    }
    else
    {
        debug("Unable to Write \n");
    }
    //__enable_irq();
    return result;
}

bool LSM303DLH::read_reg_short(int addr_i2c,int addr_reg, short *v)
{
    
    char *pv = (char *)v;
    bool result;
    
    result =  read_reg(addr_i2c,addr_reg+0,pv+1);
    result &= read_reg(addr_i2c,addr_reg+1,pv+0);
  
    
    return result;
}

LSM303DLH::LSM303DLH(PinName sda, PinName scl)     
{
   m_ptr_I2C = new I2C(sda, scl);
   init(); 
}
LSM303DLH::LSM303DLH(I2C* ptrI2C)
{
    m_ptr_I2C = ptrI2C;
    //debug( "ptr pass %d, ptr here %d   \n",(int)ptrI2C,(int)m_ptr_I2C);
    this->init();
}

void LSM303DLH::init(void)
{
    char reg_v;
 
    debug("In INIT \n");
    _offset_x = 0; 
    _offset_y = 0;
    _offset_z = 0; 
    _scale_x  = 0; 
    _scale_y  = 0; 
    _scale_z  = 0; 
    _filt_ax  = 0; 
    _filt_ay  = 0; 
    _filt_az  = 6000;
 
 
    m_ptr_I2C->frequency(100000);
    
       
    debug("in ACC \n");
    reg_v = 0;
    reg_v |= 0x01 << 5;     /* Normal mode  */
    reg_v |= 0x07;          /* X/Y/Z axis enable. */
    write_reg(addr_acc,CTRL_REG1_A,reg_v);
    reg_v = 0;
    read_reg(addr_acc,CTRL_REG1_A,&reg_v);

    reg_v = 0;
    reg_v |= 0x01 << 7;     //full read
    reg_v |= 0x01 << 3;     //hi res
    //reg_v |= 0x01 << 6;     /* 1: data MSB @ lower address */
    reg_v |= 0x01 << 4;     /* +/- 4g */
    write_reg(addr_acc,CTRL_REG4_A,reg_v);

    /* -- mag --- */
    debug("in MAG \n");
    reg_v = 0;
    reg_v |= 0x04 << 2;     /* Minimum data output rate = 15Hz */
    write_reg(addr_mag,CRA_REG_M,reg_v);

    reg_v = 0;
    //reg_v |= 0x01 << 5;     /* +-1.3Gauss */
    reg_v |= 0x07 << 5;     /* +-8.1Gauss */
    write_reg(addr_mag,CRB_REG_M,reg_v);

    reg_v = 0;              /* Continuous-conversion mode */
    write_reg(addr_mag,MR_REG_M,reg_v);
    
    debug("Out INIT \n");
    clearscreen();
}

void LSM303DLH::setOffset(float x, float y, float z)
{
    _offset_x = x;
    _offset_y = y;
    _offset_z = z;   
}

void LSM303DLH::setScale(float x, float y, float z)
{
    _scale_x = x;
    _scale_y = y;
    _scale_z = z;
}
#define _FS 4
bool LSM303DLH::read(vector &a, vector &m)
{
    
    bool result = true;
    short a_x, a_y, a_z;
    short m_x, m_y, m_z;
    #if defined(CHECK_TIME_SEQUENCE)
        Timer t;
        int usec1, usec2;
        
        t.reset();
        t.start();
    
        usec1 = t.read_us();
    #endif
   
   union{
        int16_t number;
        char byte[2];
        struct{
            char MSB;
            char LSB;
            };
        }my_test;
        vector a_test;
        
        char data_read_acc =0;
        read_reg(addr_acc,STATUS_REG_A,&data_read_acc);
        if(data_read_acc & (1<<3))//new data
        {
            result &= read_reg(addr_acc,OUT_X_A  ,&(my_test.MSB));//MSB at lower
            if(result)
            {
                result &= read_reg(addr_acc,OUT_X_A+1,&(my_test.LSB));
            }
            if(result)
            {
                //a_test.x = my_test.number;
                a_test.x = (my_test.number / (float)(32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/));
                //debug("read from reg _x:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
                setText(0,0,"read from reg _x:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
            }
            else
            {
                debug("error reading \n");
            }
            
            if(result)
            { 
                result &= read_reg(addr_acc,OUT_Y_A  ,&(my_test.MSB));//MSB at lower
            }
            if(result)
            {
                result &= read_reg(addr_acc,OUT_Y_A+1,&(my_test.LSB));
            }
            if(result)
            {
                //a_test.y = my_test.number;
                a_test.y = (my_test.number / (float)(32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/));
                //debug("read from reg _x:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
                setText(0,1,"read from reg _y:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
            }
            else
            { 
                debug("error reading \n");
            }
            
            if(result)
            { 
                result &= read_reg(addr_acc,OUT_Z_A  ,&(my_test.MSB));//MSB at lower
            }
            if(result)
            {
                result &= read_reg(addr_acc,OUT_Z_A+1,&(my_test.LSB));
            }
            if(result)
            {
                //a_test.z = my_test.number;
                a_test.z = (my_test.number / (float)(32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/));
                //debug("read from reg _x:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
                setText(0,2,"read from reg _z:(%d) %.2X %.2X \n",my_test.number, my_test.byte[1],my_test.byte[0]);
            }
            else
            { 
                debug("error reading \n");
            }
            //debug("test 4: x: %.4f y: %.4f z: %.4f \n",a_test.x,a_test.y,a_test.z);
            setText(0,4,"test 4: x: %.4f y: %.4f z: %.4f \n",a_test.x,a_test.y,a_test.z);
        }
    /*result &= read_reg_short(addr_acc, OUT_X_A, &a_x);
    result &= read_reg_short(addr_acc, OUT_Y_A, &a_y);
    result &= read_reg_short(addr_acc, OUT_Z_A, &a_z);*/
     //This test pass so its ok
    
    result &= read_reg_short(addr_mag, OUT_X_M, &m_x);
    result &= read_reg_short(addr_mag, OUT_Y_M, &m_y);
    result &= read_reg_short(addr_mag, OUT_Z_M, &m_z);
    #if defined(CHECK_TIME_SEQUENCE)
        usec2 = t.read_us();
        
        debug("%d %d %d\n", usec1, usec2, usec2-usec1);//if (debug) debug->printf("%d %d %d\n", usec1, usec2, usec2-usec1);
    #endif
    if(result == true)
    {
        // Perform simple lowpass filtering
        // Intended to stabilize heading despite
        // device vibration such as on a UGV
        
        #if 0
        if(data_read_acc & (1<<3))
        {
            a_test.x= a_test.x / (32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/);
            a_test.y= a_test.y / (32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/);
            a_test.z= a_test.z / (32768 /*half of the ADC resolution*/ / _FS/*+- 4g*/);
            
            debug("test 4: x: %.4f y: %.4f z: %.4f \n",a_test.x,a_test.y,a_test.z);
        }
        #endif
        //float( a[i] ) * pow(2.,(fs+1)) / 32768.
        
        //x/8 = reading /0xFFFF(655355)
        
        
        
       // _filt_ax = _filt_ax + (a_x - (_filt_ax >> FILTER_SHIFT));
        /*_filt_ax = _filt_ax + (ax_test - (_filt_ax >> FILTER_SHIFT));
        _filt_ay += a_y - (_filt_ay >> FILTER_SHIFT);
        _filt_az += a_z - (_filt_az >> FILTER_SHIFT);
    
        
        
        a.x = (float) (_filt_ax >> FILTER_SHIFT);
        a.y = (float) (_filt_ay >> FILTER_SHIFT);
        a.z = (float) (_filt_az >> FILTER_SHIFT);*/
        
        // offset and scale
        m.x = (m_x + _offset_x) * _scale_x;
        m.y = (m_y + _offset_y) * _scale_y;
        m.z = (m_z + _offset_z) * _scale_z;
    }
    
    return result;
}


// Returns the number of degrees from the -Y axis that it
// is pointing.
float LSM303DLH::heading()
{
    return heading((vector){0,-1,0});
}

float LSM303DLH::heading(vector from)
{
    vector a, m;

    read(a, m);
    
    ////////////////////////////////////////////////
    // compute heading       
    ////////////////////////////////////////////////

    vector temp_a = a;
    // normalize
    vector_normalize(&temp_a);
    //vector_normalize(&m);

    // compute E and N
    vector E;
    vector N;
    vector_cross(&m,&temp_a,&E);
    vector_normalize(&E);
    vector_cross(&temp_a,&E,&N);
    
    // compute heading
    float heading = atan2(vector_dot(&E,&from), vector_dot(&N,&from)) * 180/M_PI;
    if (heading < 0) heading += 360;
    
    return heading;
}

void LSM303DLH::frequency(int hz)
{
    m_ptr_I2C->frequency(hz);
}