Index: s6ddrphy/spartan6_soft_phy.v
===================================================================
--- s6ddrphy.orig/spartan6_soft_phy.v
+++ s6ddrphy/spartan6_soft_phy.v
@@ -116,7 +116,6 @@ module spartan6_soft_phy # (
     inout  [NUM_DQ-1:0]                         sd_dq,                          // Data in from SDRAM device
     output [NUM_DQS-1:0]                        sd_dm,                          // Data mask to SDRAM devices
     inout  [NUM_DQS-1:0]                        sd_dqs,                         // DQS
-    inout  [NUM_DQS-1:0]                        sd_dqs_n,                       // complimentary DQS
 
     // configuration ports
     input  [2:0]                                cfg_al,                         // Posted CAS additive latency
@@ -300,12 +299,11 @@ genvar j;
 generate
     for (j = 0; j < NUM_DQ/8*(NIBBLE_DEVICES+1) ; j = j + 1)
     begin:dqs_iob
-        IOBUFDS iobufds (
+        IOBUF iobufds (
             .O              (sd_dqs_in[j]),
             .I              (sd_dqs_out[j]),
             .T              (sd_dqs_oe_n[j]),
-            .IO             (sd_dqs[j]),
-            .IOB            (sd_dqs_n[j])
+            .IO             (sd_dqs[j])
             );
     end
 endgenerate