artf4700: Added DigitalGlitchFilter

Initial Java support from Tyler Veness.
Final java support done by Jerry Morrison.

Change-Id: I1f85eb555f9ea4c0250c4c6729d7c51a76f5bef4

wpilibj/src/athena/java/edu/wpi/first/wpilibj/Counter.java

@@ -60,8 +60,8 @@ public class Counter extends SensorBase implements CounterBase, LiveWindowSendab
     }
   }
 
-  private DigitalSource m_upSource; // /< What makes the counter count up.
-  private DigitalSource m_downSource; // /< What makes the counter count down.
+  protected DigitalSource m_upSource; // /< What makes the counter count up.
+  protected DigitalSource m_downSource; // /< What makes the counter count down.
   private boolean m_allocatedUpSource;
   private boolean m_allocatedDownSource;
   private long m_counter; // /< The FPGA counter object.

wpilibj/src/athena/java/edu/wpi/first/wpilibj/DigitalGlitchFilter.java

@@ -0,0 +1,164 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. 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 $(WIND_BASE)/WPILib.  */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj;
+
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import edu.wpi.first.wpilibj.DigitalSource;
+import edu.wpi.first.wpilibj.Encoder;
+import edu.wpi.first.wpilibj.Counter;
+
+import edu.wpi.first.wpilibj.hal.DigitalGlitchFilterJNI;
+
+/**
+ * Class to enable glitch filtering on a set of digital inputs.
+ * This class will manage adding and removing digital inputs from a FPGA glitch
+ * filter. The filter lets the user configure the time that an input must remain
+ * high or low before it is classified as high or low.
+ */
+public class DigitalGlitchFilter extends SensorBase {
+  public DigitalGlitchFilter() {
+    synchronized(m_mutex) {
+      int i = 0;
+      while (m_filterAllocated[i] != false && i < m_filterAllocated.length) {
+        i++;
+      }
+      if (i != m_filterAllocated.length) {
+        m_channelIndex = i;
+        m_filterAllocated[i] = true;
+      }
+    }
+  }
+
+  public void free() {
+    if (m_channelIndex >= 0) {
+      synchronized(m_mutex) {
+        m_filterAllocated[m_channelIndex] = false;
+      }
+    }
+  }
+
+  private static void setFilter(DigitalSource input, int channelIndex) {
+    if (input != null) { // Counter might have just one input
+      DigitalGlitchFilterJNI.setFilterSelect(input.m_port, channelIndex);
+
+      int selected = DigitalGlitchFilterJNI.getFilterSelect(input.m_port);
+      if (selected != channelIndex) {
+        throw new IllegalStateException("DigitalGlitchFilterJNI.setFilterSelect("
+            + channelIndex + ") failed -> " + selected);
+      }
+    }
+  }
+
+  /**
+   * Assigns the DigitalSource to this glitch filter.
+   *
+   * @param input The DigitalSource to add.
+   */
+  public void add(DigitalSource input) {
+    setFilter(input, m_channelIndex + 1);
+  }
+
+  /**
+   * Assigns the Encoder to this glitch filter.
+   *
+   * @param input The Encoder to add.
+   */
+  public void add(Encoder input) {
+    add(input.m_aSource);
+    add(input.m_bSource);
+  }
+
+  /**
+   * Assigns the Counter to this glitch filter.
+   *
+   * @param input The Counter to add.
+   */
+  public void add(Counter input) {
+    add(input.m_upSource);
+    add(input.m_downSource);
+  }
+
+  /**
+   * Removes this filter from the given digital input.
+   *
+   * @param input The DigitalSource to stop filtering.
+   */
+  public void remove(DigitalSource input) {
+    setFilter(input, 0);
+  }
+
+  /**
+   * Removes this filter from the given Encoder.
+   *
+   * @param input the Encoder to stop filtering.
+   */
+  public void remove(Encoder input) {
+    remove(input.m_aSource);
+    remove(input.m_bSource);
+  }
+
+  /**
+   * Removes this filter from the given Counter.
+   *
+   * @param input The Counter to stop filtering.
+   */
+  public void remove(Counter input) {
+    remove(input.m_upSource);
+    remove(input.m_downSource);
+  }
+
+  /**
+   * Sets the number of FPGA cycles that the input must hold steady to pass
+   * through this glitch filter.
+   *
+   * @param fpga_cycles The number of FPGA cycles.
+   */
+  public void setPeriodCycles(int fpga_cycles) {
+    DigitalGlitchFilterJNI.setFilterPeriod(m_channelIndex, fpga_cycles);
+  }
+
+  /**
+   * Sets the number of nanoseconds that the input must hold steady to pass
+   * through this glitch filter.
+   *
+   * @param nanoseconds The number of nanoseconds.
+   */
+  public void setPeriodNanoSeconds(long nanoseconds) {
+    int fpga_cycles = (int) (nanoseconds * kSystemClockTicksPerMicrosecond / 4 /
+                             1000);
+    setPeriodCycles(fpga_cycles);
+  }
+
+  /**
+   * Gets the number of FPGA cycles that the input must hold steady to pass
+   * through this glitch filter.
+   *
+   * @return The number of cycles.
+   */
+  public int getPeriodCycles() {
+    return DigitalGlitchFilterJNI.getFilterPeriod(m_channelIndex);
+  }
+
+  /**
+   * Gets the number of nanoseconds that the input must hold steady to pass
+   * through this glitch filter.
+   *
+   * @return The number of nanoseconds.
+   */
+  public long getPeriodNanoSeconds() {
+    int fpga_cycles = getPeriodCycles();
+
+    return (long) fpga_cycles * 1000L /
+           (long) (kSystemClockTicksPerMicrosecond / 4);
+  }
+
+  private int m_channelIndex = -1;
+  private static final Lock m_mutex = new ReentrantLock(true);
+  private static final boolean[] m_filterAllocated = new boolean[3];
+};

wpilibj/src/athena/java/edu/wpi/first/wpilibj/communication/FRCNetworkCommunicationsLibrary.java

@@ -379,6 +379,11 @@ public class FRCNetworkCommunicationsLibrary extends JNIWrapper {
      * src\main\include\NetworkCommunication\UsageReporting.h:62</i>
      */
     public static final int kResourceType_CANTalonSRX = 52;
+    /**
+     * <i>native declaration :
+     * src\main\include\NetworkCommunication\UsageReporting.h:63</i>
+     */
+    public static final int kResourceType_DigitalGlitchFilter = 53;
   };
   /**
    * <i>native declaration :

wpilibj/src/athena/java/edu/wpi/first/wpilibj/hal/DigitalGlitchFilterJNI.java

@@ -0,0 +1,8 @@
+package edu.wpi.first.wpilibj.hal;
+
+public class DigitalGlitchFilterJNI extends JNIWrapper {
+  public static native void setFilterSelect(long digital_port_pointer, int filter_index);
+  public static native int getFilterSelect(long digital_port_pointer);
+  public static native void setFilterPeriod(int filter_index, int fpga_cycles);
+  public static native int getFilterPeriod(int filter_index);
+}