ITG3200.cpp

00001 /**
00002  * Copyright (c) 2011 Pololu Corporation.  For more information, see
00003  * 
00004  * http://www.pololu.com/
00005  * http://forum.pololu.com/
00006  * 
00007  * Permission is hereby granted, free of charge, to any person
00008  * obtaining a copy of this software and associated documentation
00009  * files (the "Software"), to deal in the Software without
00010  * restriction, including without limitation the rights to use,
00011  * copy, modify, merge, publish, distribute, sublicense, and/or sell
00012  * copies of the Software, and to permit persons to whom the
00013  * Software is furnished to do so, subject to the following
00014  * conditions:
00015  * 
00016  * The above copyright notice and this permission notice shall be
00017  * included in all copies or substantial portions of the Software.
00018  * 
00019  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00020  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
00021  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00022  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
00023  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
00024  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
00025  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
00026  * OTHER DEALINGS IN THE SOFTWARE.
00027  */
00028  
00029 #include "mbed.h"
00030 #include "ITG3200.h"
00031 #include <math.h>
00032 
00033 // Defines ////////////////////////////////////////////////////////////////
00034 
00035 // The Arduino two-wire interface uses a 7-bit number for the address, 
00036 // and sets the last bit correctly based on reads and writes
00037 // mbed I2C libraries take the 7-bit address shifted left 1 bit
00038 // #define GYR_ADDRESS (0xD2 >> 1)
00039 #define GYR_ADDRESS (0x68 << 1) //ITG3200
00040 
00041 // Public Methods //////////////////////////////////////////////////////////////
00042 
00043 // Constructor
00044 ITG3200::ITG3200(PinName sda, PinName scl):
00045     _device(sda, scl)
00046 {
00047     _device.frequency(50000);
00048    
00049     //Set FS_SEL to 0x03 for proper operation.
00050     writeReg(SMPLRT_DIV_REG, 0x07);   // samplr rte 1000hz 7sample low pass filter
00051     writeReg(DLPF_FS_REG, 0x03 << 3);
00052    // writeReg(L3G4200D_CTRL_REG4, 0x20); // 2000 dps full scale default for ITG3200
00053     writeReg(PWR_MGM_REG, 0x01); // CLK_SEL to x gyro
00054 
00055     setGains(2.0,2.0,2.0);
00056     setOffsets(0.0,0.0,0.0);
00057 
00058 }
00059 
00060 // Initialize gyro again
00061 void ITG3200::init(void)
00062 {
00063     //Set FS_SEL to 0x03 for proper operation.
00064     writeReg(SMPLRT_DIV_REG, 0x07);   // samplr rte 1000hz 7sample low pass filter
00065     writeReg(DLPF_FS_REG, 0x03 << 3);
00066    // writeReg(L3G4200D_CTRL_REG4, 0x20); // 2000 dps full scale default for ITG3200
00067     writeReg(PWR_MGM_REG, 0x01); // CLK_SEL to x gyro
00068 
00069     // initialize varaibles
00070     setRevPolarity(false, false, false);
00071     setGains(1.0,1.0,1.0);
00072     setOffsets(0.0,0.0,0.0);
00073 }
00074 
00075 // read status registers of ITG3200
00076 void ITG3200::status(byte *s)
00077 {
00078     s[0]=readReg(WHO_AM_I_REG);
00079     s[1]=readReg(SMPLRT_DIV_REG);
00080     s[2]=readReg(DLPF_FS_REG);
00081     s[3]=readReg(PWR_MGM_REG);
00082 }
00083 
00084 // Writes a gyro register
00085 void ITG3200::writeReg(byte reg, byte value)
00086 {
00087     data[0] = reg;
00088     data[1] = value;
00089     
00090     _device.write(GYR_ADDRESS, data, 2);
00091 }
00092 
00093 // Reads a gyro register
00094 byte ITG3200::readReg(byte reg)
00095 {
00096     byte value = 0;
00097     
00098     _device.write(GYR_ADDRESS, &reg, 1);
00099     _device.read(GYR_ADDRESS, &value, 1);
00100 
00101     return value;
00102 }
00103 
00104 void ITG3200::setGains(float _Xgain, float _Ygain, float _Zgain) {
00105   gains[0] = _Xgain;
00106   gains[1] = _Ygain;
00107   gains[2] = _Zgain;
00108 }
00109 
00110 void ITG3200::setOffsets(int _Xoffset, int _Yoffset, int _Zoffset) {
00111   offsets[0] = _Xoffset;
00112   offsets[1] = _Yoffset;
00113   offsets[2] = _Zoffset;
00114 }
00115 
00116 void ITG3200::setRevPolarity(bool _Xpol, bool _Ypol, bool _Zpol) {
00117   polarities[0] = _Xpol ? -1 : 1;
00118   polarities[1] = _Ypol ? -1 : 1;
00119   polarities[2] = _Zpol ? -1 : 1;
00120 }
00121 
00122 
00123 void ITG3200::zeroCalibrate(unsigned int totSamples, unsigned int sampleDelayMS) {
00124   int xyz[3]; 
00125   float tmpOffsets[] = {0,0,0};
00126 
00127   for (unsigned int i = 0;i < totSamples;i++){
00128     wait_ms(sampleDelayMS);
00129     read(xyz);
00130     tmpOffsets[0] += xyz[0];
00131     tmpOffsets[1] += xyz[1];
00132     tmpOffsets[2] += xyz[2];  
00133   }
00134   setOffsets(-tmpOffsets[0] / totSamples, -tmpOffsets[1] / totSamples, -tmpOffsets[2] / totSamples);
00135 }
00136 
00137 
00138 // Reads the 3 gyro channels and stores them in vector g
00139 void ITG3200::read(int *g)
00140 {
00141     // assert the MSB of the address to get the gyro 
00142     // to do slave-transmit subaddress updating. (ITG default)
00143     data[0] = GYRO_XOUT_H_REG;
00144     _device.write(GYR_ADDRESS, data, 1); 
00145 
00146 //    Wire.requestFrom(GYR_ADDRESS, 6);
00147 //    while (Wire.available() < 6);
00148 
00149     _device.read(GYR_ADDRESS, data, 6); 
00150 
00151     uint8_t xha = data[0];
00152     uint8_t xla = data[1];
00153     uint8_t yha = data[2];
00154     uint8_t yla = data[3];
00155     uint8_t zha = data[4];
00156     uint8_t zla = data[5];
00157 
00158     g[0] = (short) (yha << 8 | yla);
00159     g[1] = (short) (xha << 8 | xla);
00160     g[2] = (short) (zha << 8 | zla);
00161 }
00162 
00163 void ITG3200::readRawCal(int *_GyroXYZ) {
00164   read(_GyroXYZ);
00165   _GyroXYZ[0] += offsets[0];
00166   _GyroXYZ[1] += offsets[1];
00167   _GyroXYZ[2] += offsets[2];
00168 }
00169 
00170 
00171 
00172 void ITG3200::read3(int x, int y, int z) {
00173   int* r2;
00174   //readings[0]=0;
00175   //readings[1]=0;
00176   //readings[2]=0;
00177   read(r2);
00178 
00179   x = r2[0];  
00180   y = r2[1]; 
00181   z = r2[2]; 
00182 }
00183 
00184 void ITG3200::readFin(float *_GyroXYZ){
00185   int xyz[3];
00186   
00187   readRawCal(xyz); // x,y,z will contain calibrated integer values from the sensor
00188   _GyroXYZ[0] =  (float)(xyz[0]) / (14.375 * polarities[0] * gains[0]);
00189   _GyroXYZ[1] =  (float)(xyz[1]) / (14.375 * polarities[1] * gains[1]);
00190   _GyroXYZ[2] =  (float)(xyz[2]) / (14.375 * polarities[2] * gains[2]);
00191 }