ADXL345_I2C.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008. All Rights Reserved.                                                         */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in $(WIND_BASE)/WPILib.  */
/*----------------------------------------------------------------------------*/

#include "ADXL345_I2C.h"
#include "DigitalModule.h"
#include "I2C.h"

const UINT8 ADXL345_I2C::kAddress;
const UINT8 ADXL345_I2C::kPowerCtlRegister;
const UINT8 ADXL345_I2C::kDataFormatRegister;
const UINT8 ADXL345_I2C::kDataRegister;
const double ADXL345_I2C::kGsPerLSB;

ADXL345_I2C::ADXL345_I2C(UINT8 moduleNumber, ADXL345_I2C::DataFormat_Range range)
        : m_i2c (NULL)
{
        DigitalModule *module = DigitalModule::GetInstance(moduleNumber);
        if (module)
        {
                m_i2c = module->GetI2C(kAddress);

                // Turn on the measurements
                m_i2c->Write(kPowerCtlRegister, kPowerCtl_Measure);
                // Specify the data format to read
                m_i2c->Write(kDataFormatRegister, kDataFormat_FullRes | (UINT8)range);
        }
}

ADXL345_I2C::~ADXL345_I2C()
{
        delete m_i2c;
        m_i2c = NULL;
}

double ADXL345_I2C::GetAcceleration(ADXL345_I2C::Axes axis)
{
        INT16 rawAccel = 0;
        if(m_i2c)
        {
                m_i2c->Read(kDataRegister + (UINT8)axis, sizeof(rawAccel), (UINT8 *)&rawAccel);

                // Sensor is little endian... swap bytes
                rawAccel = ((rawAccel >> 8) & 0xFF) | (rawAccel << 8);
        }
        return rawAccel * kGsPerLSB;
}

ADXL345_I2C::AllAxes ADXL345_I2C::GetAccelerations()
{
        AllAxes data = {0.0};
        INT16 rawData[3];
        if (m_i2c)
        {
                m_i2c->Read(kDataRegister, sizeof(rawData), (UINT8*)rawData);

                // Sensor is little endian... swap bytes
                for (INT32 i=0; i<3; i++)
                {
                        rawData[i] = ((rawData[i] >> 8) & 0xFF) | (rawData[i] << 8);
                }

                data.XAxis = rawData[0] * kGsPerLSB;
                data.YAxis = rawData[1] * kGsPerLSB;
                data.ZAxis = rawData[2] * kGsPerLSB;
        }
        return data;
}