diff --git a/litex/build/efinix/common.py b/litex/build/efinix/common.py
index 8229d816b8..ca9b73d997 100644
--- a/litex/build/efinix/common.py
+++ b/litex/build/efinix/common.py
@@ -294,7 +294,7 @@ def lower(dr):
 
 class EfinixDDRTristateImpl(LiteXModule):
     def __init__(self, io, o1, o2, oe1, oe2, i1, i2, clk):
-        assert oe1 == oe2
+        assert oe2 is None
         assert_is_signal_or_clocksignal(clk)
         platform     = LiteXContext.platform
         io_name      = platform.get_pin_name(io)
diff --git a/litex/build/io.py b/litex/build/io.py
index 9ca21baeb7..9c593795ea 100644
--- a/litex/build/io.py
+++ b/litex/build/io.py
@@ -190,20 +190,20 @@ def __init__(self, io, o1, o2, oe1, oe2, i1, i2, clk):
         _oe = Signal()
         _i  = Signal()
         self.specials += DDROutput(o1, o2, _o, clk)
-        self.specials += DDROutput(oe1, oe2, _oe, clk)
+        self.specials += DDROutput(oe1, oe2, _oe, clk) if oe2 is not None else SDROutput(oe1, _oe, clk)
         self.specials += DDRInput(_i, i1, i2, clk)
         self.specials += Tristate(io, _o, _oe, _i)
 
 class DDRTristate(Special):
-    def __init__(self, io, o1, o2, oe1, oe2, i1, i2, clk=None):
+    def __init__(self, io, o1, o2, oe1, oe2=None, i1=None, i2=None, clk=None):
         Special.__init__(self)
         self.io  = io
         self.o1  = o1
         self.o2  = o2
         self.oe1 = oe1
         self.oe2 = oe2
-        self.i1  = i1
-        self.i2  = i2
+        self.i1  = i1 if i1 is not None else Signal()
+        self.i2  = i2 if i2 is not None else Signal()
         self.clk = clk if clk is not None else ClockSignal()
 
     def iter_expressions(self):
diff --git a/litex/build/lattice/common.py b/litex/build/lattice/common.py
index 917b5af0ce..28bf247ad4 100644
--- a/litex/build/lattice/common.py
+++ b/litex/build/lattice/common.py
@@ -324,11 +324,12 @@ def lower(dr):
 
 class LatticeNXDDRTristateImpl(Module):
     def __init__(self, io, o1, o2, oe1, oe2, i1, i2, clk):
+        assert oe2 is None
         _o  = Signal()
         _oe = Signal()
         _i  = Signal()
         self.specials += DDROutput(o1, o2, _o, clk)
-        self.specials += SDROutput(oe1 | oe2, _oe, clk)
+        self.specials += SDROutput(oe1, _oe, clk)
         self.specials += DDRInput(_i, i1, i2, clk)
         self.specials += Tristate(io, _o, _oe, _i)
         _oe.attr.add("syn_useioff")
diff --git a/litex/build/xilinx/common.py b/litex/build/xilinx/common.py
index d0d6bf0f63..0f2231f70b 100644
--- a/litex/build/xilinx/common.py
+++ b/litex/build/xilinx/common.py
@@ -164,7 +164,7 @@ def __init__(self, io, o1, o2, oe1, oe2, i1, i2, clk):
         _oe_n = Signal()
         _i    = Signal()
         self.specials += DDROutput(o1, o2, _o, clk)
-        self.specials += DDROutput(~oe1, ~oe2, _oe_n, clk)
+        self.specials += DDROutput(~oe1, ~oe2, _oe_n, clk) if oe2 is not None else SDROutput(~oe1, _oe_n, clk)
         self.specials += DDRInput(_i, i1, i2, clk)
         self.specials += Instance("IOBUF",
             io_IO = io,