diff --git a/unoptimized_lr/simple_lr_automaton.py b/unoptimized_lr/simple_lr_automaton.py
index 8bb4cc4b5a7e42cc8b9236db9843faef92202fb5..f6107f99f2566f1a409a09738f001df5cde2441b 100644
--- a/unoptimized_lr/simple_lr_automaton.py
+++ b/unoptimized_lr/simple_lr_automaton.py
@@ -224,9 +224,15 @@ class LR_automaton_internal(Layout):
             # STACKS
             ("parse_stack_bus"),
             ("index_stack_bus"),
+        ])
+
 
+class LR_automaton_external(Layout):
+    def __init__(self, *, parameters):
+        super().__init__([
             # INPUT
             ("input_stream"),
+
             # OUTPUTS
             ("serialization_bus"),
             ("sideband_bus")