added a common cathode input to the seven segment display.

src/main/java/de/neemann/digital/core/element/Keys.java

@@ -274,4 +274,16 @@ public final class Keys {
     public static final Key<Boolean> RELAY_NORMALLY_CLOSED
             = new Key<>("relayNormallyClosed", false);
 
+    /**
+     * Used to indicate if the 7-seg display has a common cathode output
+     */
+    public static final Key<Boolean> COMMON_CATHODE
+            = new Key<>("commonCathode", false);
+
+    /**
+     * Used to enable the storage of the last state in the Seven Seg display.
+     */
+    public static final Key<Boolean> LED_PERSISTENCE
+            = new Key<>("ledPersistence", false);
+
 }

src/main/java/de/neemann/digital/core/element/PinDescriptions.java

@@ -30,7 +30,7 @@ public class PinDescriptions extends ImmutableList<PinDescription> {
      * @param key the key to set
      * @return this for chained calls
      */
-    PinDescriptions setLangKey(String key) {
+    public PinDescriptions setLangKey(String key) {
         for (PinDescription pd : this) {
             if (pd instanceof PinInfo) {
                 ((PinInfo) pd).setLangKey(key);

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

@@ -1,10 +1,7 @@
 package de.neemann.digital.core.io;
 
 import de.neemann.digital.core.*;
-import de.neemann.digital.core.element.Element;
+import de.neemann.digital.core.element.*;
-import de.neemann.digital.core.element.ElementAttributes;
-import de.neemann.digital.core.element.ElementTypeDescription;
-import de.neemann.digital.core.element.Keys;
 
 import static de.neemann.digital.core.element.PinInfo.input;
 
@@ -47,23 +44,14 @@ public class Out implements Element {
     /**
      * The seven segment display description
      */
-    public static final ElementTypeDescription SEVENDESCRIPTION
+    public static final ElementTypeDescription SEVENDESCRIPTION = new SevenSegTypeDescription();
-            = new ElementTypeDescription("Seven-Seg",
-            attributes -> {
-                return new Out(1, 1, 1, 1, 1, 1, 1, 1);
-            },
-            input("a"), input("b"), input("c"), input("d"), input("e"), input("f"), input("g"), input("dp"))
-            .addAttribute(Keys.LABEL)
-            .addAttribute(Keys.COLOR);
 
     /**
      * The seven segment hex display description
      */
     public static final ElementTypeDescription SEVENHEXDESCRIPTION
             = new ElementTypeDescription("Seven-Seg-Hex",
-            attributes -> {
+            attributes -> new Out(4, 1), input("d"), input("dp"))
-                return new Out(4, 1);
-            }, input("d"), input("dp"))
             .addAttribute(Keys.LABEL)
             .addAttribute(Keys.COLOR);
 
@@ -112,4 +100,33 @@ public class Out implements Element {
     public void registerNodes(Model model) {
         model.addOutput(new Signal(label, value).setDescription(description));
     }
+
+    private final static class SevenSegTypeDescription extends ElementTypeDescription {
+        private SevenSegTypeDescription() {
+            super("Seven-Seg", attributes -> {
+                if (attributes.get(Keys.COMMON_CATHODE))
+                    return new Out(1, 1, 1, 1, 1, 1, 1, 1, 1);
+                else
+                    return new Out(1, 1, 1, 1, 1, 1, 1, 1);
+            });
+            addAttribute(Keys.LABEL);
+            addAttribute(Keys.COLOR);
+            addAttribute(Keys.COMMON_CATHODE);
+            addAttribute(Keys.LED_PERSISTENCE);
+        }
+
+        @Override
+        public PinDescriptions getInputDescription(ElementAttributes attributes) throws NodeException {
+            if (attributes.get(Keys.COMMON_CATHODE)) {
+                return new PinDescriptions(
+                        input("a"), input("b"), input("c"),
+                        input("d"), input("e"), input("f"),
+                        input("g"), input("dp"), input("cc")).setLangKey(getPinLangKey());
+            } else
+                return new PinDescriptions(
+                        input("a"), input("b"), input("c"),
+                        input("d"), input("e"), input("f"),
+                        input("g"), input("dp")).setLangKey(getPinLangKey());
+        }
+    }
 }

src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java

@@ -4,13 +4,17 @@ import de.neemann.digital.core.ObservableValue;
 import de.neemann.digital.core.ObservableValues;
 import de.neemann.digital.core.Observer;
 import de.neemann.digital.core.element.ElementAttributes;
+import de.neemann.digital.core.element.Keys;
 import de.neemann.digital.core.element.PinDescriptions;
 import de.neemann.digital.draw.elements.IOState;
 import de.neemann.digital.draw.elements.Pin;
 import de.neemann.digital.draw.elements.Pins;
+import de.neemann.digital.draw.graphics.Graphic;
+import de.neemann.digital.draw.graphics.Style;
 import de.neemann.digital.draw.graphics.Vector;
 
 import static de.neemann.digital.draw.shapes.GenericShape.SIZE;
+import static de.neemann.digital.draw.shapes.GenericShape.SIZE2;
 
 /**
  * A seven seg display with seven single controllable inputs
@@ -19,8 +23,12 @@ import static de.neemann.digital.draw.shapes.GenericShape.SIZE;
  */
 public class SevenSegShape extends SevenShape {
     private final PinDescriptions inputPins;
+    private final boolean commonCatode;
+    private final boolean persistence;
+    private final boolean[] data;
     private ObservableValues inputs;
     private Pins pins;
+    private ObservableValue ccin;
 
     /**
      * Creates a new instance
@@ -32,6 +40,9 @@ public class SevenSegShape extends SevenShape {
     public SevenSegShape(ElementAttributes attr, PinDescriptions inputs, PinDescriptions outputs) {
         super(attr);
         this.inputPins = inputs;
+        commonCatode = attr.get(Keys.COMMON_CATHODE);
+        persistence = attr.get(Keys.LED_PERSISTENCE);
+        data = new boolean[8];
     }
 
     @Override
@@ -46,6 +57,8 @@ public class SevenSegShape extends SevenShape {
             pins.add(new Pin(new Vector(SIZE, SIZE * HEIGHT), inputPins.get(5)));
             pins.add(new Pin(new Vector(SIZE * 2, SIZE * HEIGHT), inputPins.get(6)));
             pins.add(new Pin(new Vector(SIZE * 3, SIZE * HEIGHT), inputPins.get(7)));
+            if (commonCatode)
+                pins.add(new Pin(new Vector(SIZE * 4, SIZE * HEIGHT), inputPins.get(8)));
         }
         return pins;
     }
@@ -55,15 +68,35 @@ public class SevenSegShape extends SevenShape {
         inputs = ioState.getInputs();
         for (ObservableValue o : inputs)
             o.addObserverToValue(guiObserver);
+        if (commonCatode)
+            ccin = inputs.get(8);
         return null;
     }
 
+    @Override
+    public void drawTo(Graphic graphic, boolean highLight) {
+        super.drawTo(graphic, highLight);
+        if (commonCatode)
+            graphic.drawLine(
+                    new Vector(SIZE * 4 - SIZE2, SIZE * HEIGHT - 1),
+                    new Vector(SIZE * 4, SIZE * HEIGHT - 1), Style.NORMAL);
+    }
 
     @Override
     protected boolean getStyle(int i) {
         if (inputs == null)
             return true;
-        else return inputs.get(i).getValueIgnoreBurn() > 0;
+
+        if (persistence && commonCatode) {
+            if (!ccin.isHighZ() && !ccin.getBool())
+                data[i] = inputs.get(i).getValueIgnoreBurn() > 0;
+            return data[i];
+        } else {
+            if (commonCatode && (ccin.isHighZ() || ccin.getBool()))
+                return false;
+
+            return inputs.get(i).getValueIgnoreBurn() > 0;
+        }
     }
 
 }

src/main/resources/lang/lang_de.xml

@@ -258,6 +258,7 @@ Die gesammte Speichergröße beträgt damit damit dx*dy*2 Speicherworte.</string
     <string name="elem_Seven-Seg_pin_f">Dieser Eingang steuert die obere linke vertikale Linie.</string>
     <string name="elem_Seven-Seg_pin_g">Dieser Eingang steuert die mittlere horizontale Linie.</string>
     <string name="elem_Seven-Seg_pin_dp">Dieser Eingang steuert den Dezimalpunkt.</string>
+    <string name="elem_Seven-Seg_pin_cc">Gemeinsame Kathode. Nur wenn hier eine Null anliegt, können die LEDs leuchten.</string>
     <string name="elem_Seven-Seg-Hex">Siebensegmentanzeige Hex</string>
     <string name="elem_Seven-Seg-Hex_tt">Siebensegmentanzeige mit einem 4 Bit hexadezimalen Eingang.</string>
     <string name="elem_Seven-Seg-Hex_pin_d">Der 4-Bit-Wert dieses Eingangs wird als Hex-Ziffer dargestellt.</string>
@@ -511,6 +512,13 @@ Zur Analyse können Sie die Schaltung im Gatterschrittmodus ausführen.</string>
     <string name="key_ExpressionFormat_tt">Anzeigeformat der Ausdrücke.</string>
     <string name="key_relayNormallyClosed">Relais ist ein Öffner</string>
     <string name="key_relayNormallyClosed_tt">Wenn gesetzt ist das Relais unbestromt geschlossen.</string>
+    <string name="key_commonCathode">Gemeinsame Kathode</string>
+    <string name="key_commonCathode_tt">Wenn gesetzt hat die Anzeige einen Ausgang mit einer gemeinsamen Kathode.</string>
+    <string name="key_ledPersistence">Träges Auge</string>
+    <string name="key_ledPersistence_tt">Die Schaltfrequenz am Bildschirm kann in der Simulation nicht so hoch werden,
+        dass das Auge kein Flimmern mehr wahrnimmt. Um dennoch das Flackern zu unterdrücken, können die LEDs auf
+        "nachleuchten" geschaltet werden.</string>
+
     <string name="lib_Logic">Logisch</string>
     <string name="lib_arithmetic">Arithmetik</string>
     <string name="lib_flipFlops">FlipFlops</string>

src/main/resources/lang/lang_en.xml

@@ -251,6 +251,7 @@
     <string name="elem_Seven-Seg_pin_f">This input controls the upper, left, vertical line.</string>
     <string name="elem_Seven-Seg_pin_g">This input controls the middle, horizontal line.</string>
     <string name="elem_Seven-Seg_pin_dp">This input controls the decimal point.</string>
+    <string name="elem_Seven-Seg_pin_cc">Common Cathode. To turn on the LEDs, this input needs to be low.</string>
     <string name="elem_Seven-Seg-Hex">Seven-Segment-Hex Display</string>
     <string name="elem_Seven-Seg-Hex_tt">Seven Segment Display with a 4 bit input</string>
     <string name="elem_Seven-Seg-Hex_pin_d">The value at this input is visualized at the display.</string>
@@ -497,6 +498,14 @@ To analyse you can run the circuit in single gate step mode.</string>
     <string name="key_ExpressionFormat_tt">Screen format of expressions.</string>
     <string name="key_relayNormallyClosed">Relay is normally closed.</string>
     <string name="key_relayNormallyClosed_tt">If set the relay is closed if the input is low.</string>
+    <string name="key_commonCathode">Common Cathode</string>
+    <string name="key_commonCathode_tt">If selected the common cathode input is also simulated.</string>
+    <string name="key_ledPersistence">Slow Eye</string>
+    <string name="key_ledPersistence_tt">It is not possible to increase the frequency so much that the flickering disappears.
+        With this option you can stabilize the display by keeping the LEDs on until the common cathode goes down again.
+        This simulates a frequency above the critical flicker fusion frequency.
+        </string>
+
     <string name="lib_Logic">Logic</string>
     <string name="lib_arithmetic">Arithmetic</string>
     <string name="lib_flipFlops">FlipFlops</string>