diff --git a/npc/playground/src/Top_Module.scala b/npc/playground/src/Top_Module.scala
index 8833350c1c..b071f6f253 100644
--- a/npc/playground/src/Top_Module.scala
+++ b/npc/playground/src/Top_Module.scala
@@ -5,11 +5,15 @@ import chisel3._
   */
 class NVboard_IOs extends Bundle{
   val ledr=Output(Vec(16,Bool()))
+
+  def loadDefault():Unit={
+    ledr:=0.U.asTypeOf(io.ledr)
+  }
 }
 class Top_Module extends Module {
   val io=IO(new NVboard_IOs)
 
-  io.ledr:=0.U.asTypeOf(io.ledr)
+  io.loadDefault()
 
   io.ledr(0):=true.B
   io.ledr(1):=false.B