diff --git a/src/main/java/de/neemann/assembler/gui/Main.java b/src/main/java/de/neemann/assembler/gui/Main.java
index 6325c9c..56db2c4 100644
--- a/src/main/java/de/neemann/assembler/gui/Main.java
+++ b/src/main/java/de/neemann/assembler/gui/Main.java
@@ -198,7 +198,7 @@ public void actionPerformed(ActionEvent actionEvent) {
 
         final RemoteInterface remoteInterface = new RemoteInterface();
 
-        ToolTipAction remoteStart = new ToolTipAction("Start", IconCreator.create("media-playback-start.png")) {
+        ToolTipAction remoteStart = new ToolTipAction("Run", IconCreator.create("media-playback-start.png")) {
             @Override
             public void actionPerformed(ActionEvent actionEvent) {
                 try {
@@ -213,7 +213,25 @@ public void actionPerformed(ActionEvent actionEvent) {
                     new ErrorMessage("Error").addCause(e).show(Main.this);
                 }
             }
-        }.setToolTip("Starts the simulated circuit.");
+        }.setToolTip("Run the progam.");
+
+        ToolTipAction remoteDebug = new ToolTipAction("Debug", IconCreator.create("debug.png")) {
+            @Override
+            public void actionPerformed(ActionEvent actionEvent) {
+                try {
+                    Program program = createProgram();
+                    if (program != null) {
+                        writeHex(program, filename);
+                        writeLst(program, filename);
+                        remoteInterface.load(makeFilename(filename, ".asm", ".hex"));
+                        remoteInterface.debug();
+                    }
+                } catch (Throwable e) {
+                    new ErrorMessage("Error").addCause(e).show(Main.this);
+                }
+            }
+        }.setToolTip("Debugs the program.");
+
         ToolTipAction remoteRun = new ToolTipAction("Run to BRK", IconCreator.create("media-skip-forward.png")) {
             @Override
             public void actionPerformed(ActionEvent actionEvent) {
@@ -301,9 +319,11 @@ public void actionPerformed(ActionEvent e) {
         toolBar.add(build.createJButtonNoText());
         toolBar.addSeparator();
         toolBar.add(remoteStart.createJButtonNoText());
+        toolBar.add(remoteStop.createJButtonNoText());
+        toolBar.addSeparator();
+        toolBar.add(remoteDebug.createJButtonNoText());
         toolBar.add(remoteStep.createJButtonNoText());
         toolBar.add(remoteRun.createJButtonNoText());
-        toolBar.add(remoteStop.createJButtonNoText());
         getContentPane().add(toolBar, BorderLayout.NORTH);
 
         pack();
diff --git a/src/main/java/de/neemann/assembler/gui/RemoteInterface.java b/src/main/java/de/neemann/assembler/gui/RemoteInterface.java
index b85d01a..e1888e6 100644
--- a/src/main/java/de/neemann/assembler/gui/RemoteInterface.java
+++ b/src/main/java/de/neemann/assembler/gui/RemoteInterface.java
@@ -33,6 +33,15 @@ public void start() throws RemoteException {
         sendRequest("start", null);
     }
 
+    /**
+     * Debugs the simulation
+     *
+     * @throws RemoteException RemoteException
+     */
+    public void debug() throws RemoteException {
+        sendRequest("debug", null);
+    }
+
     /**
      * Run to next break point
      *
diff --git a/src/main/resources/debug.png b/src/main/resources/debug.png
new file mode 100644
index 0000000..fb1de21
Binary files /dev/null and b/src/main/resources/debug.png differ