add default nettype none
diff --git a/verilog/rtl/simple_spi_master.v b/verilog/rtl/simple_spi_master.v
index 447f0f1..8a81954 100755
--- a/verilog/rtl/simple_spi_master.v
+++ b/verilog/rtl/simple_spi_master.v
@@ -1,3 +1,4 @@
+`default_nettype none
 //----------------------------------------------------------------------------
 // Module: simple_spi_master
 //