diff --git a/litex/build/microsemi/libero_soc.py b/litex/build/microsemi/libero_soc.py
index f1a5a1c52..fca2d6fa1 100644
--- a/litex/build/microsemi/libero_soc.py
+++ b/litex/build/microsemi/libero_soc.py
@@ -24,7 +24,7 @@ def _format_constraint(c):
 def _format_pdc(signame, pin, others):
     fmt_c = [_format_constraint(c) for c in ([Pins(pin)] + others)]
     r = "set_io "
-    r += "-port_name {} ".format(signame)
+    r += "-port_name {{{}}} ".format(signame)
     for c in  ([Pins(pin)] + others):
         r += _format_constraint(c)
     r += "-fixed true "