Diff: LSM303.cpp

Revision:

0:4d358fbeab6e

Child:

1:322c80f884d3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303.cpp	Thu Oct 10 06:57:53 2013 +0000
@@ -0,0 +1,159 @@
+#include "mbed.h"
+#include <math.h>
+#include "LSM303.h"
+
+I2C i2c(P0_5, P0_4);
+
+int LSM303::setup()
+{
+#if 1  
+    m_max.x = 239;
+    m_max.y = 242;
+    m_max.z = 158;
+    m_min.x = -637;
+    m_min.y = -498;
+    m_min.z = -538;
+#else    
+    m_max.x = 1;
+    m_max.y = 1;
+    m_max.z = 1;
+    m_min.x = 0;
+    m_min.y = 0;
+    m_min.z = 0;
+#endif
+    return initLSM303(ACCELE_SCALE);  // Initialize the LSM303, using a SCALE full-scale range
+}
+int LSM303::testAcc()
+{
+    if (i2c.write(LSM303_ACC, NULL, 0) ==0) return LSM303_ACC;
+    return 255;
+}
+
+int LSM303::testMag()
+{
+    if (i2c.write(LSM303_MAG, NULL, 0) ==0) 
+        if (LSM303_read(LSM303_WHO_AM_I_M)==0x3C) {
+            return LSM303_WHO_AM_I_M;
+        }
+        else {
+            return LSM303_MAG;
+        }
+    
+    return 255;
+}
+
+int LSM303::initLSM303(int fs)
+{
+    if (LSM303_write(0x27, CTRL_REG1_A) == 1) {  // 0x27 = normal power mode, all accel axes on
+        //LSM303_write(16, CTRL_REG2_A); // enable internal hp filter
+    }
+    if ((fs==8)||(fs==4))
+        LSM303_write((0x00 | (fs-fs/2-1)<<4), CTRL_REG4_A);  // set full-scale
+    else
+        LSM303_write(0x00, CTRL_REG4_A);
+    //LSM303_write(20, CRA_REG_M);  // 20 = mag 30Hz output rate
+    LSM303_write(MAG_SCALE_1_3, CRB_REG_M); //magnetic scale = +/-1.3Gauss
+    LSM303_write(0x00, MR_REG_M);  // 0x00 = continouous conversion mode
+
+    return 1;
+}
+
+float LSM303::getTiltHeading()
+{
+    //shift and scale
+    a.x = a.x / 32768 * ACCELE_SCALE;
+    a.y = a.y / 32768 * ACCELE_SCALE;
+    a.z = a.z / 32768 * ACCELE_SCALE;
+   
+    m.x = (m.x - m_min.x) / (m_max.x - m_min.x) * 2 - 1.0;
+    m.y = (m.y - m_min.y) / (m_max.y - m_min.y) * 2 - 1.0;
+    m.z = (m.z - m_min.z) / (m_max.z - m_min.z) * 2 - 1.0;
+    
+    vector_normalize(&a);
+    vector_normalize(&m);
+    //see appendix A in app note AN3192
+    pitch = asin(-a.x);
+    roll = asin(a.y/cos(pitch));
+    float heading = 0;
+    float xh = m.x * cos(pitch) + m.z * sin(pitch);
+    float yh = m.x * sin(roll) * sin(pitch) + m.y * cos(roll) - m.z * sin(roll) * cos(pitch);
+    //float zh = -m.x * cos(roll) * sin(pitch) + m.y * sin(roll) + m.z * cos(roll) * cos(pitch);      
+    heading = 180 * atan2(yh, xh)/PI;
+    if (heading < 0) heading += 360;
+        return heading;
+}
+
+void LSM303::vector_cross( const Plane *a,const Plane *b, Plane *out )
+{
+    out->x = a->y*b->z - a->z*b->y;
+    out->y = a->z*b->x - a->x*b->z;
+    out->z = a->x*b->y - a->y*b->x;
+}
+
+float LSM303::vector_dot( const Plane *a,const Plane *b )
+{
+    return a->x*b->x+a->y*b->y+a->z*b->z;
+}
+
+void LSM303::vector_normalize( Plane *a )
+{
+    float mag = sqrt(vector_dot(a,a));
+    a->x /= mag;
+    a->y /= mag;
+    a->z /= mag;
+}
+
+int LSM303::getLSM303_accel()
+{
+    char data[1] = { OUT_X_L_A | (1<<7)};
+    char out[6] = {0,0,0,0,0,0};
+    i2c.write( LSM303_ACC, data,1);
+    i2c.read( LSM303_ACC, out, 6);
+
+    a.x = short( (((short)out[1]) << 8) | out[0] );
+    a.y = short( (((short)out[3]) << 8) | out[2] );
+    a.z = short( (((short)out[5]) << 8) | out[4] );
+    return  0;
+}
+
+void LSM303::getLSM303_mag()
+{
+    char data[1] = { OUT_X_H_M };
+    char out[6];
+
+    i2c.write( LSM303_MAG, data, 1 );
+    i2c.read( LSM303_MAG, out, 6 );
+    // DLM, DLHC: register address for Z comes before Y
+    m.x = short( out[0] << 8 | out[1] );
+    m.y = short( out[4] << 8 | out[5] );
+    m.z= short( out[2] << 8 | out[3] );
+}
+
+int LSM303::LSM303_read(int address)
+{
+    if (address >= 0x20) {
+        _i2c_address = LSM303_ACC;
+    } else {
+        _i2c_address = LSM303_MAG;
+    }
+
+    char value[1];
+
+    char data[1] = { address };
+    i2c.write( _i2c_address, data, 1 );
+    i2c.read( _i2c_address, value, 1 );
+    return value[0];
+}
+
+int LSM303::LSM303_write(int data, int address)
+{
+    if (address >= 0x20) {
+        _i2c_address = LSM303_ACC;
+    } else {
+        _i2c_address = LSM303_MAG;
+    }
+
+    char out[2] = { address, data };
+    i2c.write( _i2c_address, out, 2 );
+    return 0;
+}