updates README

README.md

@@ -1,4 +1,4 @@
-## RDL Editor
+# RDL Editor
 
 This is an editor for [SystemRDL](http://www.accellera.org/activities/working-groups/systemrdl/).
 It can be installed into any Eclipse installation using the following update site url: https://minres.github.io/RDL-Editor/repository
@@ -15,3 +15,33 @@ The editor is build on top of [Eclipse Xtext](http://www.eclipse.org/Xtext/), a
 
 It has a code generator to create the register models using the [SC-Components](https://minres.github.io/SystemC-Components/) library.
 Due to the nature of Xtext this generator can easily be tailored to various needs.
+
+## How to use the standalone generator
+
+You need to have Java 11 or newer available. To run the standalone generator simply call:
+
+```
+java -jar target/com.minres.rdl.standalone-1.4.0.jar -h
+Usage: RDL2code [-h] [-v] [-f] [-I <RDL include dir>] [-o <output dir>] [-sc [-n <namespace>] [-sc-dir <dir modifier>]] [-fw [-fw-dir <dir modifier>]] <input file> <input file>
+    The following switches are supported:
+    -h                              prints help page
+    -v                              verbose output
+    -f                              force overwrite existing files
+    -I <RDL include dir>            include directory to search included RDL files
+    -o <output dir>                 output directory of generated files
+    -fw                             generate FW include files. The following sub 
+                                    switches are supported:
+        -fw-dir <dir modifier>      set the directory modifier (relative path to output dir
+    -sc                             generate SystemC stubs. The following sub switches
+                                    are supported
+        -n <namespace>              the namespace to use for the generated SystemC component
+        -sc-dir <dir modifier>      set the directory modifier (relative path to output dir
+```
+
+Generating SystemC stubs becomes
+
+```
+java -jar com.minres.rdl.standalone-1.4.0.jar -o generated-src -sc -n 'sysc::myns' <RDL file>
+```
+
+The generated SystemcC sources can then be found in the (new) directory 'generated-src'.