Diff: LSM303DLH/LSM303DLH.cpp

Revision:

3:f3796683b4c9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303DLH/LSM303DLH.cpp	Sun May 06 05:14:30 2012 +0000
@@ -0,0 +1,227 @@
+/** 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 = 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,
+    OUT_X_A     = 0x28,
+    OUT_Y_A     = 0x2A,
+    OUT_Z_A     = 0x2C,
+};
+
+bool LSM303DLH::write_reg(int addr_i2c,int addr_reg, char v)
+{
+    char data[2] = {addr_reg, v}; 
+    return LSM303DLH::_compass.write(addr_i2c, data, 2) == 0;
+}
+
+bool LSM303DLH::read_reg(int addr_i2c,int addr_reg, char *v)
+{
+    char data = addr_reg; 
+    bool result = false;
+    
+    __disable_irq();
+    if ((_compass.write(addr_i2c, &data, 1) == 0) && (_compass.read(addr_i2c, &data, 1) == 0)){
+        *v = data;
+        result = true;
+    }
+    __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):
+    _compass(sda, scl), _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)
+{
+    char reg_v;
+    _compass.frequency(100000);
+        
+    reg_v = 0;
+    reg_v |= 0x01 << 5;     /* Normal mode  */
+    reg_v |= 0x03 << 3;     /* Output data rate 1000 [Hz] */
+    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 << 6;     /* 1: data MSB @ lower address */
+    reg_v |= 0x01 << 4;     /* +/- 4g */
+    //reg_v |= 0x00 << 4;     /* +/- 2g */
+    write_reg(addr_acc,CTRL_REG4_A,reg_v);
+
+    /* -- mag --- */
+    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);
+}
+
+
+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;
+}
+
+void LSM303DLH::read(vector &a, vector &m)
+{
+    short a_x, a_y, a_z;
+    short m_x, m_y, m_z;
+    //Timer t;
+    //int usec1, usec2;
+    
+    //t.reset();
+    //t.start();
+
+    //usec1 = t.read_us();
+    read_reg_short(addr_acc, OUT_X_A, &a_x);
+    read_reg_short(addr_acc, OUT_Y_A, &a_y);
+    read_reg_short(addr_acc, OUT_Z_A, &a_z);
+    read_reg_short(addr_mag, OUT_X_M, &m_x);
+    read_reg_short(addr_mag, OUT_Y_M, &m_y);
+    read_reg_short(addr_mag, OUT_Z_M, &m_z);
+    //usec2 = t.read_us();
+    
+    //if (debug) debug->printf("%d %d %d\n", usec1, usec2, usec2-usec1);
+
+#if 0
+    // Perform simple lowpass filtering
+    // Intended to stabilize heading despite
+    // device vibration such as on a UGV
+    _filt_ax += a_x - (_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);
+#else
+    a.x = (float)a_x;
+    a.y = (float)a_y;
+    a.z = (float)a_z;
+#endif
+    
+    // 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;
+}
+
+
+// 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;
+
+    this->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)
+{
+    _compass.frequency(hz);
+}
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