wpilibc/sim/src/Encoder.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008-2017. 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 the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "Encoder.h"

#include <sstream>

#include "LiveWindow/LiveWindow.h"
#include "WPIErrors.h"

using namespace frc;

/**
 * Common initialization code for Encoders.
 * This code allocates resources for Encoders and is common to all constructors.
 *
 * The counter will start counting immediately.
 *
 * @param reverseDirection If true, counts down instead of up (this is all
 *                         relative)
 * @param encodingType     either k1X, k2X, or k4X to indicate 1X, 2X or 4X
 *                         decoding. If 4X is selected, then an encoder FPGA
 *                         object is used and the returned counts will be 4x
 *                         the encoder spec'd value since all rising and
 *                         falling edges are counted. If 1X or 2X are selected
 *                         then a counter object will be used and the returned
 *                         value will either exactly match the spec'd count or
 *                         be double (2x) the spec'd count.
 */
void Encoder::InitEncoder(int channelA, int channelB, bool reverseDirection,
                          EncodingType encodingType) {
  m_table = nullptr;
  this->channelA = channelA;
  this->channelB = channelB;
  m_encodingType = encodingType;
  m_encodingScale = encodingType == k4X ? 4 : encodingType == k2X ? 2 : 1;

  int index = 0;
  m_distancePerPulse = 1.0;

  LiveWindow::GetInstance()->AddSensor("Encoder", channelA, this);

  if (channelB < channelA) {  // Swap ports
    int channel = channelB;
    channelB = channelA;
    channelA = channel;
    m_reverseDirection = !reverseDirection;
  } else {
    m_reverseDirection = reverseDirection;
  }
  std::stringstream ss;
  ss << "dio/" << channelA << "/" << channelB;
  impl = new SimEncoder(ss.str());
  impl->Start();
}

/**
 * Encoder constructor.
 *
 * Construct a Encoder given a and b channels.
 *
 * The counter will start counting immediately.
 *
 * @param aChannel         The a channel digital input channel.
 * @param bChannel         The b channel digital input channel.
 * @param reverseDirection If true, counts down instead of up (this is all
 *                         relative)
 * @param encodingType     either k1X, k2X, or k4X to indicate 1X, 2X or 4X
 *                         decoding. If 4X is selected, then an encoder FPGA
 *                         object is used and the returned counts will be 4x
 *                         the encoder spec'd value since all rising and
 *                         falling edges are counted. If 1X or 2X are selected
 *                         then a counter object will be used and the returned
 *                         value will either exactly match the spec'd count or
 *                         be double (2x) the spec'd count.
 */
Encoder::Encoder(int aChannel, int bChannel, bool reverseDirection,
                 EncodingType encodingType) {
  InitEncoder(aChannel, bChannel, reverseDirection, encodingType);
}

/**
 * Encoder constructor.
 *
 * Construct a Encoder given a and b channels as digital inputs. This is used in
 * the case where the digital inputs are shared. The Encoder class will not
 * allocate the digital inputs and assume that they already are counted.
 *
 * The counter will start counting immediately.
 *
 * @param aSource          The source that should be used for the a channel.
 * @param bSource          the source that should be used for the b channel.
 * @param reverseDirection If true, counts down instead of up (this is all
 *                         relative)
 * @param encodingType     either k1X, k2X, or k4X to indicate 1X, 2X or 4X
 *                         decoding. If 4X is selected, then an encoder FPGA
 *                         object is used and the returned counts will be 4x
 *                         the encoder spec'd value since all rising and
 *                         falling edges are counted. If 1X or 2X are selected
 *                         then a counter object will be used and the returned
 *                         value will either exactly match the spec'd count or
 *                         be double (2x) the spec'd count.
 */
/* TODO: [Not Supported] Encoder::Encoder(DigitalSource *aSource, DigitalSource
*bSource, bool reverseDirection, EncodingType encodingType) :
        m_encoder(nullptr),
        m_counter(nullptr)
{
        m_aSource = aSource;
        m_bSource = bSource;
        m_allocatedASource = false;
        m_allocatedBSource = false;
        if (m_aSource == nullptr || m_bSource == nullptr)
                wpi_setWPIError(NullParameter);
        else
                InitEncoder(reverseDirection, encodingType);
        }*/

/**
 * Encoder constructor.
 *
 * Construct a Encoder given a and b channels as digital inputs. This is used in
 * the case where the digital inputs are shared. The Encoder class will not
 * allocate the digital inputs and assume that they already are counted.
 *
 * The counter will start counting immediately.
 *
 * @param aSource          The source that should be used for the a channel.
 * @param bSource          the source that should be used for the b channel.
 * @param reverseDirection If true, counts down instead of up (this is all
 *                         relative)
 * @param encodingType     either k1X, k2X, or k4X to indicate 1X, 2X or 4X
 *                         decoding. If 4X is selected, then an encoder FPGA
 *                         object is used and the returned counts will be 4x
 *                         the encoder spec'd value since all rising and
 *                         falling edges are counted. If 1X or 2X are selected
 *                         then a counter object will be used and the returned
 *                         value will either exactly match the spec'd count or
 *                         be double (2x) the spec'd count.
 */
/*// TODO: [Not Supported] Encoder::Encoder(DigitalSource &aSource,
DigitalSource &bSource, bool reverseDirection, EncodingType encodingType) :
        m_encoder(nullptr),
        m_counter(nullptr)
{
        m_aSource = &aSource;
        m_bSource = &bSource;
        m_allocatedASource = false;
        m_allocatedBSource = false;
        InitEncoder(reverseDirection, encodingType);
    }*/

/**
 * Reset the Encoder distance to zero.
 *
 * Resets the current count to zero on the encoder.
 */
void Encoder::Reset() { impl->Reset(); }

/**
 * Determine if the encoder is stopped.
 *
 * Using the MaxPeriod value, a boolean is returned that is true if the encoder
 * is considered stopped and false if it is still moving. A stopped encoder is
 * one where the most recent pulse width exceeds the MaxPeriod.
 *
 * @return True if the encoder is considered stopped.
 */
bool Encoder::GetStopped() const {
  throw "Simulation doesn't currently support this method.";
}

/**
 * The last direction the encoder value changed.
 *
 * @return The last direction the encoder value changed.
 */
bool Encoder::GetDirection() const {
  throw "Simulation doesn't currently support this method.";
}

/**
 * The scale needed to convert a raw counter value into a number of encoder
 * pulses.
 */
double Encoder::DecodingScaleFactor() const {
  switch (m_encodingType) {
    case k1X:
      return 1.0;
    case k2X:
      return 0.5;
    case k4X:
      return 0.25;
    default:
      return 0.0;
  }
}

/**
 * The encoding scale factor 1x, 2x, or 4x, per the requested encodingType.
 *
 * Used to divide raw edge counts down to spec'd counts.
 */
int Encoder::GetEncodingScale() const { return m_encodingScale; }

/**
 * Gets the raw value from the encoder.
 *
 * The raw value is the actual count unscaled by the 1x, 2x, or 4x scale
 * factor.
 *
 * @return Current raw count from the encoder
 */
int Encoder::GetRaw() const {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Gets the current count.
 *
 * Returns the current count on the Encoder.
 * This method compensates for the decoding type.
 *
 * @return Current count from the Encoder adjusted for the 1x, 2x, or 4x scale
 *         factor.
 */
int Encoder::Get() const {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Returns the period of the most recent pulse.
 *
 * Returns the period of the most recent Encoder pulse in seconds.
 * This method compenstates for the decoding type.
 *
 * @deprecated Use GetRate() in favor of this method.  This returns unscaled
 *             periods and GetRate() scales using value from
 *             SetDistancePerPulse().
 *
 * @return Period in seconds of the most recent pulse.
 */
double Encoder::GetPeriod() const {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Sets the maximum period for stopped detection.
 *
 * Sets the value that represents the maximum period of the Encoder before it
 * will assume that the attached device is stopped. This timeout allows users
 * to determine if the wheels or other shaft has stopped rotating.
 * This method compensates for the decoding type.
 *
 * @deprecated Use SetMinRate() in favor of this method.  This takes unscaled
 *             periods and SetMinRate() scales using value from
 *             SetDistancePerPulse().
 *
 * @param maxPeriod The maximum time between rising and falling edges before the
 *                  FPGA will report the device stopped. This is expressed in
 *                  seconds.
 */
void Encoder::SetMaxPeriod(double maxPeriod) {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Get the distance the robot has driven since the last reset.
 *
 * @return The distance driven since the last reset as scaled by the value from
 *         SetDistancePerPulse().
 */
double Encoder::GetDistance() const {
  return m_distancePerPulse * impl->GetPosition();
}

/**
 * Get the current rate of the encoder.
 *
 * Units are distance per second as scaled by the value from
 * SetDistancePerPulse().
 *
 * @return The current rate of the encoder.
 */
double Encoder::GetRate() const {
  return m_distancePerPulse * impl->GetVelocity();
}

/**
 * Set the minimum rate of the device before the hardware reports it stopped.
 *
 * @param minRate The minimum rate.  The units are in distance per second as
 *                scaled by the value from SetDistancePerPulse().
 */
void Encoder::SetMinRate(double minRate) {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Set the distance per pulse for this encoder.
 *
 * This sets the multiplier used to determine the distance driven based on the
 * count value from the encoder. Do not include the decoding type in this scale.
 * The library already compensates for the decoding type. Set this value based
 * on the encoder's rated Pulses per Revolution and factor in gearing reductions
 * following the encoder shaft. This distance can be in any units you like,
 * linear or angular.
 *
 * @param distancePerPulse The scale factor that will be used to convert pulses
 *                         to useful units.
 */
void Encoder::SetDistancePerPulse(double distancePerPulse) {
  if (m_reverseDirection) {
    m_distancePerPulse = -distancePerPulse;
  } else {
    m_distancePerPulse = distancePerPulse;
  }
}

/**
 * Set the direction sensing for this encoder.
 *
 * This sets the direction sensing on the encoder so that it could count in the
 * correct software direction regardless of the mounting.
 *
 * @param reverseDirection true if the encoder direction should be reversed
 */
void Encoder::SetReverseDirection(bool reverseDirection) {
  throw "Simulation doesn't currently support this method.";
}

/**
 * Set which parameter of the encoder you are using as a process control
 * variable.
 *
 * @param pidSource An enum to select the parameter.
 */
void Encoder::SetPIDSourceType(PIDSourceType pidSource) {
  m_pidSource = pidSource;
}

/**
 * Implement the PIDSource interface.
 *
 * @return The current value of the selected source parameter.
 */
double Encoder::PIDGet() {
  switch (m_pidSource) {
    case PIDSourceType::kDisplacement:
      return GetDistance();
    case PIDSourceType::kRate:
      return GetRate();
    default:
      return 0.0;
  }
}

void Encoder::UpdateTable() {
  if (m_table != nullptr) {
    m_table->PutNumber("Speed", GetRate());
    m_table->PutNumber("Distance", GetDistance());
    m_table->PutNumber("Distance per Tick", m_reverseDirection
                                                ? -m_distancePerPulse
                                                : m_distancePerPulse);
  }
}

void Encoder::StartLiveWindowMode() {}

void Encoder::StopLiveWindowMode() {}

std::string Encoder::GetSmartDashboardType() const {
  if (m_encodingType == k4X)
    return "Quadrature Encoder";
  else
    return "Encoder";
}

void Encoder::InitTable(std::shared_ptr<ITable> subTable) {
  m_table = subTable;
  UpdateTable();
}

std::shared_ptr<ITable> Encoder::GetTable() const { return m_table; }