[wpilib] Separate ExpansionHubServo into separate Servo and CRServo classes (#8770)

This removes the confusion of the `ExpansionHubServo` class serving both
purposes, and thus having a `set` method that functions as `setPosition`
when in servo mode and `setThrottle` when not in continuous mode. It
also removes the `setContinuousRotationMethod` which could be confused
for a method that switches the actual servo firmware itself from servo
to continuous mode, which is not a thing that is physically possible I
think.

---------

Signed-off-by: Zach Harel <zach@zharel.me>

wpilibc/src/main/native/include/wpi/hardware/expansionhub/ExpansionHub.hpp

@@ -12,6 +12,7 @@
 namespace wpi {
 class ExpansionHubServo;
 class ExpansionHubMotor;
+class ExpansionHubCRServo;
 
 /** This class controls a REV ExpansionHub plugged in over USB to Systemcore. */
 class ExpansionHub {
@@ -29,6 +30,7 @@ class ExpansionHub {
 
   friend class ExpansionHubServo;
   friend class ExpansionHubMotor;
+  friend class ExpansionHubCRServo;
 
   /**
    * Constructs a servo at the requested channel on this hub.
@@ -40,6 +42,8 @@ class ExpansionHub {
    */
   ExpansionHubServo MakeServo(int channel);
 
+  ExpansionHubCRServo MakeCRServo(int channel);
+
   /**
    * Constructs a motor at the requested channel on this hub.
    *

wpilibc/src/main/native/include/wpi/hardware/expansionhub/ExpansionHubCRServo.hpp

@@ -0,0 +1,105 @@
+// 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/time.hpp"
+
+namespace wpi {
+
+/** This class controls a specific servo in continuous rotation mode hooked up
+ * to an ExpansionHub. */
+class ExpansionHubCRServo {
+ public:
+  /**
+   * Constructs a continuous rotation servo at the requested channel on a
+   * specific USB port.
+   *
+   * @sa ExpansionHubServo for a servo mode, or non-continuous rotation servo
+   * @param usbId The USB port ID the hub is connected to
+   * @param channel The servo channel
+   */
+  ExpansionHubCRServo(int usbId, int channel);
+  ~ExpansionHubCRServo() noexcept;
+
+  /**
+   * Set the servo throttle.
+   *
+   * Throttle values range from -1.0 to 1.0 corresponding to full reverse to
+   * full forward.
+   *
+   * @param value Throttle from -1.0 to 1.0.
+   */
+  void SetThrottle(double value);
+
+  /**
+   * 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 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 SetThrottle.
+   *
+   * @param reversed True to reverse, false for normal
+   */
+  void SetReversed(bool reversed);
+
+ private:
+  wpi::units::microsecond_t GetFullRangeScaleFactor() const;
+
+  ExpansionHub m_hub;
+  int m_channel;
+
+  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

wpilibc/src/main/native/include/wpi/hardware/expansionhub/ExpansionHubServo.hpp

@@ -14,12 +14,14 @@
 
 namespace wpi {
 
-/** This class controls a specific servo hooked up to an ExpansionHub. */
+/** 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
    */
@@ -34,16 +36,16 @@ class ExpansionHubServo {
    *
    * @param value Position from 0.0 to 1.0.
    */
-  void Set(double value);
+  void SetPosition(double value);
 
   /**
-   * Sets the servo angle
+   * Sets the servo angle.
    *
-   * Servo angles range from 0 to 180 degrees. Use Set() with your own scaler
-   * for other angle ranges.
+   * Servo angles range defaults to 0 to 180 degrees, but can be changed with
+   * setAngleRange().
    *
-   * @param angle Position in angle units. Will be scaled between 0 and 180
-   * degrees
+   * @param angle Position in angle units. Will be clamped to be within the
+   * current angle range.
    */
   void SetAngle(wpi::units::degree_t angle);
 
@@ -76,7 +78,7 @@ class ExpansionHubServo {
   bool IsHubConnected() const { return m_hub.IsHubConnected(); }
 
   /**
-   * Sets the angle range for the setAngle call.
+   * Sets the angle range for the SetAngle call.
    * By default, this is 0 to 180 degrees.
    *
    * Maximum angle must be greater than minimum angle.
@@ -102,22 +104,12 @@ class ExpansionHubServo {
   /**
    * Sets whether the servo is reversed.
    *
-   * This will reverse both Set() and SetAngle().
+   * This will reverse both SetPosition() and SetAngle().
    *
    * @param reversed True to reverse, false for normal
    */
   void SetReversed(bool reversed);
 
-  /**
-   * Enables or disables continuous rotation mode.
-   *
-   * In continuous rotation mode, the servo will interpret
-   * Set() commands to between -1.0 and 1.0, instead of 0.0 to 1.0.
-   *
-   * @param enable True to enable continuous rotation mode, false to disable
-   */
-  void SetContinuousRotationMode(bool enable);
-
  private:
   wpi::units::microsecond_t GetFullRangeScaleFactor();
   wpi::units::degree_t GetServoAngleRange();
@@ -132,7 +124,6 @@ class ExpansionHubServo {
   wpi::units::microsecond_t m_maxPwm = 2400_us;
 
   bool m_reversed = false;
-  bool m_continuousMode = false;
 
   wpi::nt::IntegerPublisher m_pulseWidthPublisher;
   wpi::nt::IntegerPublisher m_framePeriodPublisher;