Add examples for DMA, DutyCycle, DutyCycleEncoder and AddressableLED (#2100)

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

@@ -0,0 +1,35 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. 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 <frc/DigitalInput.h>
+#include <frc/DutyCycle.h>
+#include <frc/TimedRobot.h>
+#include <frc/smartdashboard/SmartDashboard.h>
+
+class Robot : public frc::TimedRobot {
+  frc::DigitalInput m_input{0};         // Input channel
+  frc::DutyCycle m_dutyCycle{m_input};  // Duty cycle input
+
+ public:
+  void RobotInit() override {}
+
+  void RobotPeriodic() override {
+    // Duty Cycle Frequency in Hz
+    auto frequency = m_dutyCycle.GetFrequency();
+
+    // Output of duty cycle, ranging from 0 to 1
+    // 1 is fully on, 0 is fully off
+    auto output = m_dutyCycle.GetOutput();
+
+    frc::SmartDashboard::PutNumber("Frequency", frequency);
+    frc::SmartDashboard::PutNumber("Duty Cycle", output);
+  }
+};
+
+#ifndef RUNNING_FRC_TESTS
+int main() { return frc::StartRobot<Robot>(); }
+#endif