ExpansionHubServo.hpp

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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
 
#pragma once
 
#include <memory>
 
#include "wpi/hardware/expansionhub/ExpansionHub.hpp"
#include "wpi/nt/BooleanTopic.hpp"
#include "wpi/nt/IntegerTopic.hpp"
#include "wpi/units/angle.hpp"
#include "wpi/units/time.hpp"
 
namespace wpi {
 
/** This class controls a specific servo in positional/servo mode hooked up to
 * an ExpansionHub. */
class ExpansionHubServo {
 public:
  /**
   * Constructs a servo at the requested channel on a specific USB port.
   *
   * @sa ExpansionHubCRServo if the servo is in continuous rotation mode
   * @param usbId The USB port ID the hub is connected to
   * @param channel The servo channel
   */
  ExpansionHubServo(int usbId, int channel);
  ~ExpansionHubServo() noexcept;
 
  /**
   * Set the servo position.
   *
   * Servo values range from 0.0 to 1.0 corresponding to the range of full left
   * to full right.
   *
   * @param value Position from 0.0 to 1.0.
   */
  void SetPosition(double value);
 
  /**
   * Sets the servo angle.
   *
   * Servo angles range defaults to 0 to 180 degrees, but can be changed with
   * setAngleRange().
   *
   * @param angle Position in angle units. Will be clamped to be within the
   * current angle range.
   */
  void SetAngle(wpi::units::degree_t angle);
 
  /**
   * Sets the raw pulse width output on the servo.
   *
   * @param pulseWidth Pulse width
   */
  void SetPulseWidth(wpi::units::microsecond_t pulseWidth);
 
  /**
   * Sets if the servo output is enabled or not. Defaults to false.
   *
   * @param enabled True to enable, false to disable
   */
  void SetEnabled(bool enabled);
 
  /**
   * Sets the frame period for the servo. Defaults to 20ms.
   *
   * @param framePeriod The frame period
   */
  void SetFramePeriod(wpi::units::microsecond_t framePeriod);
 
  /**
   * Gets if the underlying ExpansionHub is connected.
   *
   * @return True if hub is connected, otherwise false
   */
  bool IsHubConnected() const { return m_hub.IsHubConnected(); }
 
  /**
   * Sets the angle range for the SetAngle call.
   * By default, this is 0 to 180 degrees.
   *
   * Maximum angle must be greater than minimum angle.
   *
   * @param minAngle Minimum angle
   * @param maxAngle Maximum angle
   */
  void SetAngleRange(wpi::units::degree_t minAngle,
                     wpi::units::degree_t maxAngle);
 
  /**
   * Sets the PWM range for the servo.
   * By default, this is 600 to 2400 microseconds.
   *
   * Maximum must be greater than minimum.
   *
   * @param minPwm Minimum PWM
   * @param maxPwm Maximum PWM
   */
  void SetPWMRange(wpi::units::microsecond_t minPwm,
                   wpi::units::microsecond_t maxPwm);
 
  /**
   * Sets whether the servo is reversed.
   *
   * This will reverse both SetPosition() and SetAngle().
   *
   * @param reversed True to reverse, false for normal
   */
  void SetReversed(bool reversed);
 
 private:
  wpi::units::microsecond_t GetFullRangeScaleFactor();
  wpi::units::degree_t GetServoAngleRange();
 
  ExpansionHub m_hub;
  int m_channel;
 
  wpi::units::degree_t m_maxServoAngle = 180.0_deg;
  wpi::units::degree_t m_minServoAngle = 0.0_deg;
 
  wpi::units::microsecond_t m_minPwm = 600_us;
  wpi::units::microsecond_t m_maxPwm = 2400_us;
 
  bool m_reversed = false;
 
  wpi::nt::IntegerPublisher m_pulseWidthPublisher;
  wpi::nt::IntegerPublisher m_framePeriodPublisher;
  wpi::nt::BooleanPublisher m_enabledPublisher;
};
}  // namespace wpi