LSM303DLHC.cpp

00001 /** LSM303DLHC Interface Library
00002  *
00003  * base on code by Michael Shimniok http://bot-thoughts.com
00004  *
00005  *  and on test program by @tosihisa and 
00006  *
00007  *  and on Pololu sample library for LSM303DLHC breakout by ryantm:
00008  *
00009  * Copyright (c) 2011 Pololu Corporation. For more information, see
00010  *
00011  * http://www.pololu.com/
00012  * http://forum.pololu.com/
00013  *
00014  * FREE FALL INTERRUPT CODE ADDED BY TASOS CHARISIS
00015  *
00016  * Permission is hereby granted, free of charge, to any person
00017  * obtaining a copy of this software and associated documentation
00018  * files (the "Software"), to deal in the Software without
00019  * restriction, including without limitation the rights to use,
00020  * copy, modify, merge, publish, distribute, sublicense, and/or sell
00021  * copies of the Software, and to permit persons to whom the
00022  * Software is furnished to do so, subject to the following
00023  * conditions:
00024  *
00025  * The above copyright notice and this permission notice shall be
00026  * included in all copies or substantial portions of the Software.
00027  * 
00028  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00029  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
00030  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00031  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
00032  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
00033  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
00034  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
00035  * OTHER DEALINGS IN THE SOFTWARE.
00036  */
00037 #include "mbed.h"
00038 #include "LSM303DLHC.h"
00039 
00040 
00041 const int addr_acc = 0x32;
00042 const int addr_mag = 0x3c;
00043 
00044 enum REG_ADDRS {
00045     /* --- Mag --- */
00046     CRA_REG_M   = 0x00,
00047     CRB_REG_M   = 0x01,
00048     MR_REG_M    = 0x02,
00049     OUT_X_M     = 0x03,
00050     OUT_Y_M     = 0x05,
00051     OUT_Z_M     = 0x07,
00052     /* --- Acc --- */
00053     CTRL_REG1_A = 0x20,
00054     CTRL_REG3_A = 0x22,
00055     CTRL_REG4_A = 0x23,
00056     CTRL_REG5_A = 0x24,
00057     REFERENCE_A = 0x26,
00058     INT1_CFG_A  = 0x30,
00059     INT1_THS_A  = 0x32,
00060     INT1_DURATION_A = 0x33,
00061     OUT_X_A     = 0x28,
00062     OUT_Y_A     = 0x2A,
00063     OUT_Z_A     = 0x2C,
00064 };
00065 
00066 bool LSM303DLHC::write_reg(int addr_i2c,int addr_reg, char v)
00067 {
00068     char data[2] = {addr_reg, v}; 
00069     return LSM303DLHC::_LSM303.write(addr_i2c, data, 2) == 0;
00070 }
00071 
00072 bool LSM303DLHC::read_reg(int addr_i2c,int addr_reg, char *v)
00073 {
00074     char data = addr_reg; 
00075     bool result = false;
00076     
00077     __disable_irq();
00078     if ((_LSM303.write(addr_i2c, &data, 1) == 0) && (_LSM303.read(addr_i2c, &data, 1) == 0)){
00079         *v = data;
00080         result = true;
00081     }
00082     __enable_irq();
00083     return result;
00084 }
00085 
00086 
00087 LSM303DLHC::LSM303DLHC(PinName sda, PinName scl):
00088     _LSM303(sda, scl)
00089 {
00090     char reg_v;
00091     _LSM303.frequency(200000);
00092         
00093     reg_v = 0;
00094     
00095     reg_v |= 0x57;          /* Normal mode 100 Hz X/Y/Z axis enable. */
00096     write_reg(addr_acc,CTRL_REG1_A,reg_v);
00097 
00098     reg_v = 0;
00099    // reg_v |= 0x01 << 6;     /* 1: data MSB @ lower address */
00100     reg_v = 0x01 << 4;     /* +/- 4g */
00101     write_reg(addr_acc,CTRL_REG4_A,reg_v);
00102 
00103     /* -- mag --- */
00104     reg_v = 0;
00105     reg_v |= 0x06 << 2;     /* Minimum magnetic data output rate = 75Hz */
00106     write_reg(addr_mag,CRA_REG_M,reg_v);
00107 
00108     reg_v = 0;
00109     reg_v |= 0x01 << 5;     /* +-1.3Gauss */
00110     //reg_v |= 0x07 << 5;     /* +-8.1Gauss */
00111     write_reg(addr_mag,CRB_REG_M,reg_v);
00112 
00113     reg_v = 0;              /* Continuous-conversion mode */
00114     write_reg(addr_mag,MR_REG_M,reg_v);
00115 
00116 /** ------------------------FREE FALL INTERRUPT SETTINGS-------------------------------------------
00117 --------------------CALIBRATION VALUES ARE g THRESHOLD AND DURATION----------------------------------
00118 **/
00119     
00120     //Setup Free Fall INT as INT1
00121         reg_v = 0x40;     /* AOI1 interrupt on INT1 */
00122         write_reg(addr_acc,CTRL_REG3_A,reg_v);  
00123         
00124         reg_v = 0x64;   /* 100 Counts --> 0.2g at +- 4g scale (2mg/LSB*/
00125         write_reg(addr_acc,INT1_THS_A,reg_v); 
00126         
00127         reg_v = 0x5;   /* 5 Counts --> 50ms duration at 100Hz sampling */
00128         write_reg(addr_acc,INT1_DURATION_A,reg_v); 
00129         
00130         reg_v = 0x95;   /* Enable AOI and low events not high on all axes */
00131         write_reg(addr_acc,INT1_CFG_A,reg_v);
00132 }
00133 
00134 
00135 bool LSM303DLHC::read(float *ax, float *ay, float *az, float *mx, float *my, float *mz) {
00136     char acc[6], mag[6];
00137  
00138     if (recv(addr_acc, OUT_X_A, acc, 6) && recv(addr_mag, OUT_X_M, mag, 6)) {
00139         *ax = float(short(acc[1] << 8 | acc[0]))/8192;  //32768/4=8192
00140         *ay =  float(short(acc[3] << 8 | acc[2]))/8192;
00141         *az =  float(short(acc[5] << 8 | acc[4]))/8192;
00142         //full scale magnetic readings are from -2048 to 2047
00143         //gain is x,y =1100; z = 980 LSB/gauss
00144         *mx = float(short(mag[0] << 8 | mag[1]))/1100;
00145         *mz = float(short(mag[2] << 8 | mag[3]))/980;
00146         *my = float(short(mag[4] << 8 | mag[5]))/1100;
00147  
00148         return 1;
00149     }
00150  
00151     return 0;
00152 }
00153 
00154 
00155 bool LSM303DLHC::recv(char sad, char sub, char *buf, int length) {
00156     if (length > 1) sub |= 0x80;
00157  
00158     return _LSM303.write(sad, &sub, 1, true) == 0 && _LSM303.read(sad, buf, length) == 0;
00159 }