add default nettype none
diff --git a/verilog/rtl/digital_pll_controller.v b/verilog/rtl/digital_pll_controller.v
index d4f7a4c..1437c93 100644
--- a/verilog/rtl/digital_pll_controller.v
+++ b/verilog/rtl/digital_pll_controller.v
@@ -1,3 +1,4 @@
+`default_nettype none
 // (True) digital PLL
 //
 // Output goes to a trimmable ring oscillator (see documentation).