[examples] Adding XRP java and cpp examples for Timed Robot (#8599)

Adding an example (one C++ and one Java) for using TimedRobot with the
XRP.

wpilibcExamples/src/main/cpp/examples/Xrptimed/cpp/Robot.cpp

@@ -0,0 +1,57 @@
+// 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.
+
+#include "Robot.h"
+
+Robot::Robot() {
+  wpi::SendableRegistry::AddChild(&m_drive, &m_leftMotor);
+  wpi::SendableRegistry::AddChild(&m_drive, &m_rightMotor);
+
+  // We need to invert one side of the drivetrain so that positive voltages
+  // result in both sides moving forward. Depending on how your robot's
+  // gearbox is constructed, you might have to invert the left side instead.
+  m_rightMotor.SetInverted(true);
+}
+
+/**
+ * This function is called every 20 ms, no matter the mode. Use
+ * this for items like diagnostics that you want ran during disabled,
+ * autonomous, teleoperated and test.
+ *
+ * <p> This runs after the mode specific periodic functions, but before
+ * LiveWindow and SmartDashboard integrated updating.
+ */
+void Robot::RobotPeriodic() {}
+
+// This function is only once each time Autonomous is enabled
+void Robot::AutonomousInit() {
+  m_timer.Restart();
+}
+
+// This function is called periodically during autonomous mode
+void Robot::AutonomousPeriodic() {
+  // Drive for 2 seconds
+  if (m_timer.Get() < 2_s) {
+    // Drive forwards half speed, make sure to turn input squaring off
+    m_drive.ArcadeDrive(0.5, 0.0, false);
+  } else {
+    // Stop robot
+    m_drive.ArcadeDrive(0.0, 0.0, false);
+  }
+}
+
+// This function is only once each time telop is enabled
+void Robot::TeleopInit() {}
+
+// This function is called periodically during teleop mode
+void Robot::TeleopPeriodic() {
+  m_drive.ArcadeDrive(-m_XboxController.GetLeftY(),
+                      -m_XboxController.GetRightX());
+}
+
+#ifndef RUNNING_FRC_TESTS
+int main() {
+  return frc::StartRobot<Robot>();
+}
+#endif

wpilibcExamples/src/main/cpp/examples/Xrptimed/include/Robot.h

@@ -0,0 +1,31 @@
+// 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 <frc/TimedRobot.h>
+#include <frc/Timer.h>
+#include <frc/XboxController.h>
+#include <frc/drive/DifferentialDrive.h>
+#include <frc/xrp/XRPMotor.h>
+
+class Robot : public frc::TimedRobot {
+ public:
+  Robot();
+  void RobotPeriodic() override;
+  void AutonomousInit() override;
+  void AutonomousPeriodic() override;
+  void TeleopInit() override;
+  void TeleopPeriodic() override;
+
+ private:
+  frc::XRPMotor m_leftMotor{0};
+  frc::XRPMotor m_rightMotor{1};
+  frc::XboxController m_XboxController{0};
+  frc::Timer m_timer;
+
+  frc::DifferentialDrive m_drive{
+      [&](double output) { m_leftMotor.Set(output); },
+      [&](double output) { m_rightMotor.Set(output); }};
+};

wpilibcExamples/src/main/cpp/examples/examples.json

@@ -609,6 +609,22 @@
       "xrp"
     ]
   },
+  {
+    "name": "XRP Timed",
+    "description": "An very basic timed robot program that can be used with the XRP reference robot design.",
+    "tags": [
+      "XRP",
+      "Differential Drive",
+      "XboxController"
+    ],
+    "foldername": "Xrptimed",
+    "gradlebase": "cppxrp",
+    "mainclass": "Main",
+    "commandversion": 2,
+    "extravendordeps": [
+      "xrp"
+    ]
+  },
   {
     "name": "StateSpaceFlywheel",
     "description": "Control a flywheel using a state-space model (based on values from CAD), with a Kalman Filter and LQR.",