diff --git a/top.vhd b/top.vhd
index 1d0ac76..a7160f3 100644
--- a/top.vhd
+++ b/top.vhd
@@ -36,7 +36,7 @@ end entity config_top;
 
 
 architecture RTL of config_top is
-  type fsm_state_t is (IDLE, CMD, REPLY, HANG);
+  type fsm_state_t is (IDLE, CMD, EXEC, REPLY, HANG);
 
 
 
@@ -187,6 +187,8 @@ begin  -- architecture RTL
           if byte_ready_rx = '1' then
           -- TODO: Byte received. Do something
           end if;
+        when EXEC =>
+          null;                         -- TODO: handle Wishbone communication
         when REPLY =>
           -- TODO: if reply_is_error = '1' then: wait for response that
           -- indicates that the error is handled. Then switch back to command