add default nettype none
diff --git a/verilog/dv/caravel/tbuart.v b/verilog/dv/caravel/tbuart.v
index 97c4283..f623a60 100644
--- a/verilog/dv/caravel/tbuart.v
+++ b/verilog/dv/caravel/tbuart.v
@@ -1,3 +1,4 @@
+`default_nettype none
 /*
  *  PicoSoC - A simple example SoC using PicoRV32
  *