diff --git a/src/main/java/de/neemann/digital/core/element/Keys.java b/src/main/java/de/neemann/digital/core/element/Keys.java
index d629a7e68..04f925bfa 100644
--- a/src/main/java/de/neemann/digital/core/element/Keys.java
+++ b/src/main/java/de/neemann/digital/core/element/Keys.java
@@ -523,9 +523,12 @@ public final class Keys {
     /**
      * Used to indicate if the 7-seg display has a common cathode output
      */
-    public static final Key<Boolean> COMMON_CATHODE
+    public static final Key<Boolean> COMMON_CONNECTION
             = new Key<>("commonCathode", false).allowGroupEdit();
 
+    public static final Key<Boolean> COMMON_ANODE
+            = new Key<>("commonAnode", false).setDependsOn(COMMON_CONNECTION).allowGroupEdit();
+
     /**
      * Used to enable the storage of the last state in the Seven Seg display.
      */
diff --git a/src/main/java/de/neemann/digital/core/io/Out.java b/src/main/java/de/neemann/digital/core/io/Out.java
index 1037d9012..35640d605 100644
--- a/src/main/java/de/neemann/digital/core/io/Out.java
+++ b/src/main/java/de/neemann/digital/core/io/Out.java
@@ -142,23 +142,30 @@ public class Out implements Element {
     private final static class SevenSegTypeDescription extends ElementTypeDescription {
         private SevenSegTypeDescription() {
             super("Seven-Seg", attributes -> {
-                if (attributes.get(Keys.COMMON_CATHODE))
+                if (attributes.get(Keys.COMMON_CONNECTION))
                     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.COLOR);
-            addAttribute(Keys.COMMON_CATHODE);
+            addAttribute(Keys.COMMON_CONNECTION);
+            addAttribute(Keys.COMMON_ANODE);
             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());
+        public PinDescriptions getInputDescription(ElementAttributes attributes) {
+            if (attributes.get(Keys.COMMON_CONNECTION)) {
+                if (attributes.get(Keys.COMMON_ANODE))
+                    return new PinDescriptions(
+                            input("a"), input("b"), input("c"),
+                            input("d"), input("e"), input("f"),
+                            input("g"), input("dp"), input("ca")).setLangKey(getPinLangKey());
+                else
+                    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"),
diff --git a/src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java b/src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java
index 85ecf5cb4..7e70eddb3 100644
--- a/src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java
+++ b/src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java
@@ -27,9 +27,10 @@ import static de.neemann.digital.draw.shapes.GenericShape.SIZE2;
  */
 public class SevenSegShape extends SevenShape {
     private final PinDescriptions inputPins;
-    private final boolean commonCatode;
+    private final boolean commonConnection;
     private final boolean persistence;
     private final boolean[] data;
+    private final boolean anode;
     private ObservableValues inputValues;
     private Value[] inputs = new Value[8];
     private Value ccin;
@@ -45,7 +46,8 @@ public class SevenSegShape extends SevenShape {
     public SevenSegShape(ElementAttributes attr, PinDescriptions inputs, PinDescriptions outputs) {
         super(attr);
         this.inputPins = inputs;
-        commonCatode = attr.get(Keys.COMMON_CATHODE);
+        commonConnection = attr.get(Keys.COMMON_CONNECTION);
+        anode = attr.get(Keys.COMMON_ANODE);
         persistence = attr.get(Keys.LED_PERSISTENCE);
         data = new boolean[8];
     }
@@ -62,7 +64,7 @@ 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)
+            if (commonConnection)
                 pins.add(new Pin(new Vector(SIZE * 4, SIZE * HEIGHT), inputPins.get(8)));
         }
         return pins;
@@ -79,7 +81,7 @@ public class SevenSegShape extends SevenShape {
     @Override
     public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
-        if (commonCatode)
+        if (commonConnection)
             graphic.drawLine(
                     new Vector(SIZE * 4 - SIZE2, SIZE * HEIGHT - 1),
                     new Vector(SIZE * 4, SIZE * HEIGHT - 1), Style.NORMAL);
@@ -90,7 +92,7 @@ public class SevenSegShape extends SevenShape {
         if (inputValues != null) {
             for (int i = 0; i < 8; i++)
                 inputs[i] = inputValues.get(i).getCopy();
-            if (commonCatode)
+            if (commonConnection)
                 ccin = inputValues.get(8).getCopy();
         }
     }
@@ -100,15 +102,18 @@ public class SevenSegShape extends SevenShape {
         if (inputValues == null)
             return true;
 
-        if (persistence && commonCatode) {
+        if (persistence && commonConnection) {
             if (!ccin.isHighZ() && !ccin.getBool())
                 data[i] = inputs[i].getBool();
             return data[i];
         } else {
-            if (commonCatode && (ccin.isHighZ() || ccin.getBool()))
+            if (commonConnection && (ccin.isHighZ() || (ccin.getBool() ^ anode)))
                 return false;
 
-            return inputs[i].getBool();
+            if (inputs[i].isHighZ())
+                return false;
+
+            return inputs[i].getBool() ^ anode;
         }
     }
 
diff --git a/src/test/java/de/neemann/digital/draw/shapes/SevenSegShapeTest.java b/src/test/java/de/neemann/digital/draw/shapes/SevenSegShapeTest.java
new file mode 100644
index 000000000..c7a5af3f7
--- /dev/null
+++ b/src/test/java/de/neemann/digital/draw/shapes/SevenSegShapeTest.java
@@ -0,0 +1,121 @@
+package de.neemann.digital.draw.shapes;
+
+import de.neemann.digital.core.ObservableValue;
+import de.neemann.digital.core.ObservableValues;
+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 junit.framework.TestCase;
+
+public class SevenSegShapeTest extends TestCase {
+
+    public void testCommonCathode() {
+        ElementAttributes attr = new ElementAttributes()
+                .set(Keys.COMMON_CONNECTION, true)
+                .set(Keys.COMMON_ANODE, false);
+
+        ObservableValue a = new ObservableValue("a", 1);
+        ObservableValue b = new ObservableValue("b", 1);
+        ObservableValue c = new ObservableValue("c", 1);
+        ObservableValue d = new ObservableValue("d", 1);
+        ObservableValue e = new ObservableValue("e", 1);
+        ObservableValue f = new ObservableValue("f", 1);
+        ObservableValue g = new ObservableValue("g", 1);
+        ObservableValue dp = new ObservableValue("dp", 1);
+        ObservableValue cc = new ObservableValue("cc", 1);
+        final ObservableValues observableValues = new ObservableValues(a, b, c, d, e, f, g, dp, cc);
+        PinDescriptions inputs = new PinDescriptions(observableValues);
+        SevenSegShape ss = new SevenSegShape(attr, inputs, new PinDescriptions());
+        IOState state = new IOState(observableValues, null, null);
+        ss.applyStateMonitor(state, null);
+
+        checkValue(false, ss, 0, a, 0, 1, cc, 0, 1);
+        checkValue(false, ss, 0, a, 0, 1, cc, 1, 1);
+        checkValue(false, ss, 0, a, 1, 1, cc, 0, 1);
+        checkValue(false, ss, 0, a, 1, 1, cc, 1, 1);
+
+        checkValue(false, ss, 0, a, 0, 1, cc, 0, 0);
+        checkValue(false, ss, 0, a, 0, 1, cc, 1, 0);
+        checkValue(false, ss, 0, a, 1, 1, cc, 0, 0);
+        checkValue(false, ss, 0, a, 1, 1, cc, 1, 0);
+
+        checkValue(false, ss, 0, a, 0, 0, cc, 0, 1);
+        checkValue(false, ss, 0, a, 0, 0, cc, 1, 1);
+        checkValue(false, ss, 0, a, 1, 0, cc, 0, 1);
+        checkValue(false, ss, 0, a, 1, 0, cc, 1, 1);
+
+        checkValue(false, ss, 0, a, 0, 0, cc, 0, 0);
+        checkValue(false, ss, 0, a, 0, 0, cc, 1, 0);
+        checkValue(true, ss, 0, a, 1, 0, cc, 0, 0);
+        checkValue(false, ss, 0, a, 1, 0, cc, 1, 0);
+
+        checkValue(false, ss, 1, b, 0, 1, cc, 0, 1);
+        checkValue(false, ss, 1, b, 0, 1, cc, 1, 1);
+        checkValue(false, ss, 1, b, 1, 1, cc, 0, 1);
+        checkValue(false, ss, 1, b, 1, 1, cc, 1, 1);
+
+        checkValue(false, ss, 1, b, 0, 1, cc, 0, 0);
+        checkValue(false, ss, 1, b, 0, 1, cc, 1, 0);
+        checkValue(false, ss, 1, b, 1, 1, cc, 0, 0);
+        checkValue(false, ss, 1, b, 1, 1, cc, 1, 0);
+
+        checkValue(false, ss, 1, b, 0, 0, cc, 0, 1);
+        checkValue(false, ss, 1, b, 0, 0, cc, 1, 1);
+        checkValue(false, ss, 1, b, 1, 0, cc, 0, 1);
+        checkValue(false, ss, 1, b, 1, 0, cc, 1, 1);
+
+        checkValue(false, ss, 1, b, 0, 0, cc, 0, 0);
+        checkValue(false, ss, 1, b, 0, 0, cc, 1, 0);
+        checkValue(true, ss, 1, b, 1, 0, cc, 0, 0);
+        checkValue(false, ss, 1, b, 1, 0, cc, 1, 0);
+    }
+
+    public void testCommonAnode() {
+        ElementAttributes attr = new ElementAttributes()
+                .set(Keys.COMMON_CONNECTION, true)
+                .set(Keys.COMMON_ANODE, true);
+
+        ObservableValue a = new ObservableValue("a", 1);
+        ObservableValue b = new ObservableValue("b", 1);
+        ObservableValue c = new ObservableValue("c", 1);
+        ObservableValue d = new ObservableValue("d", 1);
+        ObservableValue e = new ObservableValue("e", 1);
+        ObservableValue f = new ObservableValue("f", 1);
+        ObservableValue g = new ObservableValue("g", 1);
+        ObservableValue dp = new ObservableValue("dp", 1);
+        ObservableValue cc = new ObservableValue("ca", 1);
+        final ObservableValues observableValues = new ObservableValues(a, b, c, d, e, f, g, dp, cc);
+        PinDescriptions inputs = new PinDescriptions(observableValues);
+        SevenSegShape ss = new SevenSegShape(attr, inputs, new PinDescriptions());
+        IOState state = new IOState(observableValues, null, null);
+        ss.applyStateMonitor(state, null);
+
+        checkValue(false, ss, 0, a, 0, 1, cc, 0, 1);
+        checkValue(false, ss, 0, a, 0, 1, cc, 1, 1);
+        checkValue(false, ss, 0, a, 1, 1, cc, 0, 1);
+        checkValue(false, ss, 0, a, 1, 1, cc, 1, 1);
+
+        checkValue(false, ss, 0, a, 0, 1, cc, 0, 0);
+        checkValue(false, ss, 0, a, 0, 1, cc, 1, 0);
+        checkValue(false, ss, 0, a, 1, 1, cc, 0, 0);
+        checkValue(false, ss, 0, a, 1, 1, cc, 1, 0);
+
+        checkValue(false, ss, 0, a, 0, 0, cc, 0, 1);
+        checkValue(false, ss, 0, a, 0, 0, cc, 1, 1);
+        checkValue(false, ss, 0, a, 1, 0, cc, 0, 1);
+        checkValue(false, ss, 0, a, 1, 0, cc, 1, 1);
+
+        checkValue(false, ss, 0, a, 0, 0, cc, 0, 0);
+        checkValue(true, ss, 0, a, 0, 0, cc, 1, 0);
+        checkValue(false, ss, 0, a, 1, 0, cc, 0, 0);
+        checkValue(false, ss, 0, a, 1, 0, cc, 1, 0);
+    }
+
+    private void checkValue(boolean expected, SevenSegShape ss, int i, ObservableValue a, int av, int ahz, ObservableValue b, int bv, int bhz) {
+        a.set(av, ahz);
+        b.set(bv, bhz);
+        ss.readObservableValues();
+        assertEquals(expected, ss.getStyle(i));
+    }
+}
\ No newline at end of file