diff --git a/litedram/common.py b/litedram/common.py
index cd8c330..ad95707 100644
--- a/litedram/common.py
+++ b/litedram/common.py
@@ -165,13 +165,14 @@ def cmd_request_rw_layout(a, ba):
 class tXXDController(Module):
     def __init__(self, txxd):
         self.valid = valid = Signal()
-        self.ready = ready = Signal()
-        ready.attr.add("no_retiming")
+        self.ready = Signal()
 
         # # #
 
         self.comb += self.ready.eq(1)
         if txxd is not None:
+            ready = Signal()
+            ready.attr.add("no_retiming")
             count = Signal(max=max(txxd, 2))
             self.sync += \
                 If(valid,
@@ -185,3 +186,4 @@ class tXXDController(Module):
                     count.eq(count - 1),
                     If(count == 1, ready.eq(1))
                 )
+            self.comb += self.ready.eq(ready)