diff --git a/tb/verilator/sim_main.cpp b/tb/verilator/sim_main.cpp
index fb6459e..55999c9 100644
--- a/tb/verilator/sim_main.cpp
+++ b/tb/verilator/sim_main.cpp
@@ -167,7 +167,7 @@ static void init_and_clock(){
 	//main clock
 	if ( main_time % 40 == 1 ) {
 		top->clock = 1;
-	} else if ( main_time % 40 == 26 ) {
+	} else if ( main_time % 40 == 21 ) {
 		top->clock = 0;
 		main_cycle ++;
 	}