add default nettype none
diff --git a/verilog/rtl/mprj_io.v b/verilog/rtl/mprj_io.v
index 5bc4483..11a7dc3 100644
--- a/verilog/rtl/mprj_io.v
+++ b/verilog/rtl/mprj_io.v
@@ -1,3 +1,4 @@
+`default_nettype none
 module mprj_io #(
     parameter AREA1PADS = 18	// Highest numbered pad in area 1
 ) (