Implements a common PWMSpeedController base class

There was a lot of duplicated code between all 7 PWM speed controllers.
This moves all the duplicated code down to a base class, that will make
it easier to add speed controllers in future years if needed again. Also
if we need to add a method to all speed controllers, we only have to do
it in 1 place, and not 7.

Change-Id: I25eb1d097c0f5f7dbd7656db2f4a30d006d50f98

wpilibc/Athena/src/PWMSpeedController.cpp

@@ -0,0 +1,67 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2016. 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 "PWMSpeedController.h"
+
+/**
+ * Constructor for a PWM Speed Controller connected via PWM
+ * @param channel The PWM channel that the controller is attached to. 0-9 are
+ * on-board, 10-19 are on the MXP port
+ */
+PWMSpeedController::PWMSpeedController(uint32_t channel) : SafePWM(channel) {
+}
+
+/**
+ * Set the PWM value.
+ *
+ * The PWM value is set using a range of -1.0 to 1.0, appropriately
+ * scaling the value for the FPGA.
+ *
+ * @param speed The speed value between -1.0 and 1.0 to set.
+ * @param syncGroup Unused interface.
+ */
+void PWMSpeedController::Set(float speed, uint8_t syncGroup) {
+  SetSpeed(m_isInverted ? -speed : speed);
+}
+
+/**
+ * Get the recently set value of the PWM.
+ *
+ * @return The most recently set value for the PWM between -1.0 and 1.0.
+ */
+float PWMSpeedController::Get() const { return GetSpeed(); }
+
+/**
+ * Common interface for disabling a motor.
+ */
+void PWMSpeedController::Disable() { SetRaw(kPwmDisabled); }
+
+/**
+* Common interface for inverting direction of a speed controller.
+* @param isInverted The state of inversion, true is inverted.
+*/
+void PWMSpeedController::SetInverted(bool isInverted) { m_isInverted = isInverted; }
+
+/**
+ * Common interface for the inverting direction of a speed controller.
+ *
+ * @return isInverted The state of inversion, true is inverted.
+ *
+ */
+bool PWMSpeedController::GetInverted() const { return m_isInverted; }
+
+/**
+ * Write out the PID value as seen in the PIDOutput base object.
+ *
+ * @param output Write out the PWM value as was found in the PIDController
+ */
+void PWMSpeedController::PIDWrite(float output) { Set(output); }
+
+/**
+ * Common interface to stop the motor until Set is called again.
+ */
+void PWMSpeedController::StopMotor() { this->SafePWM::StopMotor(); }