File content as of revision 3:eea9733ca427:

/**
 * @author Aaron Berk
 *
 * @section LICENSE
 *
 * Copyright (c) 2010 ARM Limited
 *
 * 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.
 *
 * @section DESCRIPTION
 *
 * ITG-3200 triple axis, digital interface, gyroscope.
 *
 * Datasheet:
 *
 * http://invensense.com/mems/gyro/documents/PS-ITG-3200-00-01.4.pdf
 */

#include "ITG3200.h"

ITG3200::ITG3200(PinName sda, PinName scl) : i2c_(sda, scl) {

    offset[0] = offset[1] = offset[2] = 0;

    //400kHz, fast mode.
    i2c_.frequency(400000);
    
    //Set FS_SEL to 0x03 for proper operation.
    //See datasheet for details.
    char tx[2];
    tx[0] = DLPF_FS_REG;
    //FS_SEL bits sit in bits 4 and 3 of DLPF_FS register.
    tx[1] = 0x03 << 3;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

char ITG3200::getWhoAmI(void){

    //WhoAmI Register address.
    char tx = WHO_AM_I_REG;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    return rx;

}

void ITG3200::setWhoAmI(char address){

    char tx[2];
    tx[0] = WHO_AM_I_REG;
    tx[1] = address;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

char ITG3200::getSampleRateDivider(void){

    char tx = SMPLRT_DIV_REG;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);

    return rx;

}

void ITG3200::setSampleRateDivider(char divider){

    char tx[2];
    tx[0] = SMPLRT_DIV_REG;
    tx[1] = divider;

    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

int ITG3200::getInternalSampleRate(void){

    char tx = DLPF_FS_REG;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    //DLPF_CFG == 0 -> sample rate = 8kHz.
    if(rx == 0){
        return 8;
    } 
    //DLPF_CFG = 1..7 -> sample rate = 1kHz.
    else if(rx >= 1 && rx <= 7){
        return 1;
    }
    //DLPF_CFG = anything else -> something's wrong!
    else{
        return -1;
    }
    
}

void ITG3200::setLpBandwidth(char bandwidth){

    char tx[2];
    tx[0] = DLPF_FS_REG;
    //Bits 4,3 are required to be 0x03 for proper operation.
    tx[1] = bandwidth | (0x03 << 3);
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

char ITG3200::getInterruptConfiguration(void){

    char tx = INT_CFG_REG;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    return rx;

}

void ITG3200::setInterruptConfiguration(char config){

    char tx[2];
    tx[0] = INT_CFG_REG;
    tx[1] = config;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

bool ITG3200::isPllReady(void){

    char tx = INT_STATUS;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    //ITG_RDY bit is bit 4 of INT_STATUS register.
    if(rx & 0x04){
        return true;
    }
    else{
        return false;
    }
    
}

bool ITG3200::isRawDataReady(void){

    char tx = INT_STATUS;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    //RAW_DATA_RDY bit is bit 1 of INT_STATUS register.
    if(rx & 0x01){
        return true;
    }
    else{
        return false;
    }
    
}

int ITG3200::getRawTemperature(void){

    char tx = TEMP_OUT_H_REG;
    char rx[2];
    
    i2c_.write(I2C_ADDRESS, &tx, 1);
    
    i2c_.read(I2C_ADDRESS, rx, 2);
    
    // Readings are expressed in 16bit 2's complement, so we must first
    // concatenate two bytes to make a word and sign extend it to obtain
    // correct negative values.
    // ARMCC compiles char as unsigned, which means no sign extension is
    // performed during bitwise operations to chars. But we should make sure
    // that lower byte won't extend its sign past upper byte for other
    // compilers if we want to keep it portable.
    return int16_t(((unsigned)rx[0] << 8) | (unsigned)rx[1]);
}

float ITG3200::getTemperature(){
    //Offset = -35 degrees, 13200 counts. 280 counts/degrees C.
    return 35.0 + ((getRawTemperature() + 13200)/280.0);
    
}

int ITG3200::getGyroX(void){

    char tx = GYRO_XOUT_H_REG;
    char rx[2];
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, rx, 2);
    
    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);

    return output;

}

int ITG3200::getGyroY(void){

    char tx = GYRO_YOUT_H_REG;
    char rx[2];
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, rx, 2);
    
    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);

    return output;

}

int ITG3200::getGyroZ(void){

    char tx = GYRO_ZOUT_H_REG;
    char rx[2];
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, rx, 2);
    
    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);

    return output;
    
}

void ITG3200::getRawGyroXYZ(int readings[3]){

    char tx = GYRO_XOUT_H_REG;
    char rx[2];
    
    i2c_.write(I2C_ADDRESS, &tx, 1);
    
    i2c_.read(I2C_ADDRESS, rx, 6);
    
    for(int i = 0; i < 3; i++)
        readings[i] = int16_t((unsigned) rx[i * 2 + 0] << 8) | ((unsigned) rx[i * 2 + 1]);
}

char ITG3200::getPowerManagement(void){

    char tx = PWR_MGM_REG;
    char rx;
    
    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, &tx, 1);
    
    i2c_.read((ITG3200_I2C_ADDRESS << 1) | 0x01, &rx, 1);
    
    return rx;

}

void ITG3200::setPowerManagement(char config){

    char tx[2];
    tx[0] = PWR_MGM_REG;
    tx[1] = config;

    i2c_.write((ITG3200_I2C_ADDRESS << 1) & 0xFE, tx, 2);

}

void ITG3200::calibrate(double time){
    static const double deltaTime = 0.002;
    long sum[3] = {0};
    int sumCount = 0;
    for(; 0 < time; time -= deltaTime){
        int gyro[3];
        getGyroXYZ(gyro);
        for(int i = 0; i < 3; i++)
            sum[i] += gyro[i];
        sumCount++;
    }
    
    // Avoid zero division
    if(0 < sumCount){
        for(int i = 0; i < 3; i++)
            offset[i] = sum[i] / sumCount;
    }
}