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

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

@@ -0,0 +1,50 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <array>
+
+#include <frc/AddressableLED.h>
+#include <frc/TimedRobot.h>
+#include <frc/smartdashboard/SmartDashboard.h>
+
+class Robot : public frc::TimedRobot {
+  // PWM port 0
+  // Must be a PWM header, not MXP or DIO
+  frc::AddressableLED m_led{0};
+  std::array<frc::AddressableLED::LEDData, 12> m_ledBuffer;  // Reuse the buffer
+  int m_count = 0;
+
+ public:
+  void RobotInit() override {
+    // Default to a length of 12, start empty output
+    // Length is expensive to set, so only set it once, then just update data
+    m_led.SetLength(12);
+    m_led.SetData(m_ledBuffer);
+    m_led.Start();
+  }
+
+  void RobotPeriodic() override {
+    // Zero out all LEDs
+    for (auto& ledData : m_ledBuffer) {
+      ledData.SetLED(0, 0, 0);
+    }
+
+    // Set 1 single LED to red
+    m_ledBuffer[m_count].SetLED(50, 0, 0);
+
+    // Continue moving LED
+    m_count++;
+    if (m_count >= 12) m_count = 0;
+
+    // Buffer must be written to update.
+    m_led.SetData(m_ledBuffer);
+  }
+};
+
+#ifndef RUNNING_FRC_TESTS
+int main() { return frc::StartRobot<Robot>(); }
+#endif