diff --git a/common.py b/common.py
index e293e8c..ebb37b9 100755
--- a/common.py
+++ b/common.py
@@ -2273,6 +2273,12 @@
     >>> convert_pinname('gnd', 'openram_nand4_dec')
     'GND'
 
+    >>> convert_pinname('en')
+    'EN'
+
+    >>> convert_pinname('EN')
+    'EN'
+
     """
     s = old_pinname
     u = old_pinname.upper()
@@ -2366,6 +2372,9 @@
     if 'gn' == s:
         return u
 
+    if 'EN' == u:
+        return u
+
     # Extract _N from things like GATEN
     # QN -> Q_N
     if re.match('^([A-Z]*[^I_])[N]$', u):