[examples] Add Limit Switch snippets (#7946)

wpilibcExamples/src/main/cpp/snippets/LimitSwitch/cpp/Robot.cpp

@@ -0,0 +1,50 @@
+// 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 <frc/DigitalInput.h>
+#include <frc/Encoder.h>
+#include <frc/Joystick.h>
+#include <frc/TimedRobot.h>
+#include <frc/motorcontrol/PWMVictorSPX.h>
+
+/**
+ * Limit Switch snippets for frc-docs.
+ * https://docs.wpilib.org/en/stable/docs/software/hardware-apis/sensors/limit-switch.html
+ */
+class Robot : public frc::TimedRobot {
+ public:
+  void TeleopPeriodic() override { SetMotorSpeed(m_joystick.GetRawAxis(2)); }
+  void SetMotorSpeed(double speed) {
+    if (speed > 0) {
+      if (m_toplimitSwitch.Get()) {
+        // We are going up and top limit is tripped so stop
+        m_motor.Set(0);
+      } else {
+        // We are going up but top limit is not tripped so go at commanded speed
+        m_motor.Set(speed);
+      }
+    } else {
+      if (m_bottomlimitSwitch.Get()) {
+        // We are going down and bottom limit is tripped so stop
+        m_motor.Set(0);
+      } else {
+        // We are going down but bottom limit is not tripped so go at commanded
+        // speed
+        m_motor.Set(speed);
+      }
+    }
+  }
+
+ private:
+  frc::DigitalInput m_toplimitSwitch{0};
+  frc::DigitalInput m_bottomlimitSwitch{1};
+  frc::PWMVictorSPX m_motor{0};
+  frc::Joystick m_joystick{0};
+};
+
+#ifndef RUNNING_FRC_TESTS
+int main() {
+  return frc::StartRobot<Robot>();
+}
+#endif

wpilibcExamples/src/main/cpp/snippets/snippets.json

@@ -52,5 +52,15 @@
     ],
     "foldername": "EncoderHoming",
     "gradlebase": "cpp"
+  },
+  {
+    "name": "LimitSwitch",
+    "description": "Snippets of Limit Switch for frc-docs.",
+    "tags": [
+      "Hardware",
+      "Digital Input"
+    ],
+    "foldername": "LimitSwitch",
+    "gradlebase": "cpp"
   }
 ]