added some documentation

src/main/java/de/neemann/digital/core/io/Button.java

@@ -10,10 +10,15 @@ import de.neemann.digital.core.element.Keys;
 import de.neemann.digital.lang.Lang;
 
 /**
+ * The Button
+ *
  * @author hneemann
  */
 public class Button implements Element {
 
+    /**
+     * The Button description
+     */
     public static final ElementTypeDescription DESCRIPTION = new ElementTypeDescription(Button.class)
             .addAttribute(Keys.ROTATE)
             .addAttribute(Keys.LABEL);
@@ -21,6 +26,11 @@ public class Button implements Element {
     private final ObservableValue output;
     private final String label;
 
+    /**
+     * Creates a new instance
+     *
+     * @param attributes the attributes
+     */
     public Button(ElementAttributes attributes) {
         output = new ObservableValue("out", 1);
         label = attributes.get(Keys.LABEL);

src/main/java/de/neemann/digital/core/io/Const.java

@@ -10,10 +10,15 @@ import de.neemann.digital.core.element.Keys;
 import de.neemann.digital.lang.Lang;
 
 /**
+ * A constant
+ *
  * @author hneemann
  */
 public class Const implements Element {
 
+    /**
+     * The Constant description
+     */
     public static final ElementTypeDescription DESCRIPTION = new ElementTypeDescription(Const.class)
             .addAttribute(Keys.ROTATE)
             .addAttribute(Keys.BITS)
@@ -21,6 +26,11 @@ public class Const implements Element {
 
     private final ObservableValue output;
 
+    /**
+     * Creates a new instance
+     *
+     * @param attributes the attributes
+     */
     public Const(ElementAttributes attributes) {
         output = new ObservableValue("out", attributes.get(Keys.BITS));
         output.setValue(attributes.get(Keys.VALUE));

src/main/java/de/neemann/digital/core/io/In.java

@@ -10,6 +10,8 @@ import de.neemann.digital.core.element.Keys;
 import de.neemann.digital.lang.Lang;
 
 /**
+ * The Input
+ *
  * @author hneemann
  */
 public class In implements Element {

src/main/java/de/neemann/digital/core/io/Out.java

@@ -11,10 +11,15 @@ import de.neemann.digital.core.element.Keys;
 import static de.neemann.digital.core.element.PinInfo.input;
 
 /**
+ * The different outputs
+ *
  * @author hneemann
  */
 public class Out implements Element {
 
+    /**
+     * The Input description
+     */
     public static final ElementTypeDescription DESCRIPTION
             = new ElementTypeDescription(Out.class, input("in")) {
         @Override
@@ -27,12 +32,18 @@ public class Out implements Element {
             .addAttribute(Keys.LABEL)
             .addAttribute(Keys.DESCRIPTION);
 
+    /**
+     * The LED description
+     */
     public static final ElementTypeDescription LEDDESCRIPTION
             = new ElementTypeDescription("LED", Out.class, input("in"))
             .addAttribute(Keys.ROTATE)
             .addAttribute(Keys.LABEL)
             .addAttribute(Keys.COLOR);
 
+    /**
+     * The seven segment display description
+     */
     public static final ElementTypeDescription SEVENDESCRIPTION
             = new ElementTypeDescription("Seven-Seg",
             attributes -> {
@@ -42,6 +53,9 @@ public class Out implements Element {
             .addAttribute(Keys.LABEL)
             .addAttribute(Keys.COLOR);
 
+    /**
+     * The seven segment hex display description
+     */
     public static final ElementTypeDescription SEVENHEXDESCRIPTION
             = new ElementTypeDescription("Seven-Seg-Hex",
             attributes -> {
@@ -54,11 +68,21 @@ public class Out implements Element {
     private final String label;
     private ObservableValue value;
 
+    /**
+     * Creates a new instance
+     *
+     * @param attributes the attributes
+     */
     public Out(ElementAttributes attributes) {
         bits = new int[]{attributes.getBits()};
         label = attributes.get(Keys.LABEL);
     }
 
+    /**
+     * Creates a new instance
+     *
+     * @param bits the bitcount of the different inputs
+     */
     public Out(int... bits) {
         this.bits = bits;
         label = null;

src/main/java/de/neemann/digital/core/io/Probe.java

@@ -11,11 +11,15 @@ import de.neemann.digital.core.element.Keys;
 import static de.neemann.digital.core.element.PinInfo.input;
 
 /**
+ * The measurement Probe
+ *
  * @author hneemann
  */
 public class Probe implements Element {
 
-
+    /**
+     * The Probe description
+     */
     public static final ElementTypeDescription DESCRIPTION
             = new ElementTypeDescription("Probe", Probe.class, input("in"))
             .addAttribute(Keys.ROTATE)
@@ -24,6 +28,11 @@ public class Probe implements Element {
     private final String label;
     private ObservableValue value;
 
+    /**
+     * Creates a new instance
+     *
+     * @param attributes the attributes
+     */
     public Probe(ElementAttributes attributes) {
         label = attributes.get(Keys.LABEL);
     }

src/main/java/de/neemann/digital/core/io/package-info.java

@@ -0,0 +1,6 @@
+/**
+ * The basic IO elements like Buttons, Inputs, Outputs, LEDs
+ *
+ * @author hneemann
+ */
+package de.neemann.digital.core.io;

src/main/java/de/neemann/digital/core/package-info.java

@@ -8,4 +8,4 @@
  *
  * @author hneemann
  */
-package de.neemann.digital.core;
+package de.neemann.digital.core;