upm/src/adxrs610/adxrs610.cxx

/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2015 Intel Corporation.
 *
 * This program and the accompanying materials are made available under the
 * terms of the The MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 */

#include <iostream>

#include "upm_string_parser.hpp"
#include "adxrs610.hpp"

using namespace std;
using namespace upm;

static bool operator!(mraa::MraaIo &mraaIo)
{
  return mraaIo.getMraaDescriptors() == NULL;
}

ADXRS610::ADXRS610(int dPin, int tPin, float aref) :
  m_aioData(new mraa::Aio(dPin)), m_aioTemp(new mraa::Aio(tPin))
{
  // ADC resolution of data and temp should be the same...
  m_aRes = (1 << m_aioData->getBit());
  m_aref = aref;

  setZeroPoint(calibrateZeroPoint());
  setDeadband(0.0);

  m_centerVolts = aref / 2.0;
}

ADXRS610::ADXRS610(std::string initStr) : mraaIo(initStr)
{
  if(!mraaIo.aios.empty())
  {
    m_aioData = &mraaIo.aios[0];
    m_aioTemp = &mraaIo.aios[1];
  }
  else
  {
    throw std::invalid_argument(std::string(__FUNCTION__) +
                            ": mraa_i2c_init() failed");
  }

  std::vector<std::string> upmTokens;

  if (!mraaIo.getLeftoverStr().empty()) {
    upmTokens = UpmStringParser::parse(mraaIo.getLeftoverStr());
  }

  // ADC resolution of data and temp should be the same...
  m_aref = 5.0;
  m_aRes = (1 << m_aioData->getBit());
  setZeroPoint(calibrateZeroPoint());
  setDeadband(0.0);

  for (std::string tok : upmTokens) {
    if(tok.substr(0, 5) == "aref:") {
      m_aref = std::stof(tok.substr(5));
    }
  }

  m_centerVolts = m_aref / 2.0;
}

ADXRS610::~ADXRS610()
{
  if(!mraaIo)
  {
    delete m_aioData;
    delete m_aioTemp;
  }
}

float ADXRS610::getDataVolts()
{
  int val = m_aioData->read();

  return(float(val) * (m_aref / float(m_aRes)));
}

float ADXRS610::getTemperatureVolts()
{
  int val = m_aioTemp->read();

  return(float(val) * (m_aref / float(m_aRes)));
}

float ADXRS610::calibrateZeroPoint(unsigned int samples)
{
  // The gyro should be in a stable, non-moving state

  float sum = 0;
  for (unsigned int i=0; i<samples; i++)
    sum += getDataVolts();

  return sum / samples;
}

float ADXRS610::getTemperature()
{
  float tempV = getTemperatureVolts();

  // nominal 2.5 volts at 25C
  if (tempV > m_centerVolts)
    return (m_temperatureNom + ((tempV - m_centerVolts) / m_temperatureCoeff));
  else
    return (m_temperatureNom - ((m_centerVolts - tempV) / m_temperatureCoeff));
}

float ADXRS610::getAngularVelocity()
{
  float dataV = getDataVolts();

  // check the deadband
  if (dataV < (m_zeroPoint + m_deadband) &&
      dataV > (m_zeroPoint - m_deadband))
    return 0.0;

  if (dataV > m_zeroPoint)
    return ((dataV - m_zeroPoint) / m_degreeCoeff);
  else
    return -((m_zeroPoint - dataV) / m_degreeCoeff);
}

std::vector<float> ADXRS610::getGyroscope()
{
  float dataV = getDataVolts();

  // check the deadband
  if (dataV < (m_zeroPoint + m_deadband) &&
      dataV > (m_zeroPoint - m_deadband))
    return std::vector<float>{0 ,0 ,0};
  
  if (dataV > m_zeroPoint)
  {
    float v = ((dataV - m_zeroPoint) / m_degreeCoeff);
    return std::vector<float>{0 ,0 , v};
  }
  else
  {
    float v = -((m_zeroPoint - dataV) / m_degreeCoeff);
    return std::vector<float>{0 ,0 , v};
  }
}