diff --git a/des/sim/makefile b/des/sim/makefile
index fc382be..feb004f 100644
--- a/des/sim/makefile
+++ b/des/sim/makefile
@@ -30,7 +30,7 @@ sim : tb_des.ghw
 tb_des.ghw : ../rtl/*.vhd tb_des.vhd
 	ghdl -a ../rtl/des_pkg.vhd ../rtl/des.vhd tb_des.vhd
 	ghdl -e tb_des
-	ghdl -r tb_des --wave=tb_des.ghw  --stop-time=1400ns
+	ghdl -r tb_des --wave=tb_des.ghw  --stop-time=3us
 	
 wave : tb_des.ghw
 	gtkwave tb_des.ghw
@@ -38,4 +38,4 @@ wave : tb_des.ghw
 clean :
 	echo "# cleaning simulation files"
 	rm -f tb_des.ghw
-	rm -f work*.cf
\ No newline at end of file
+	rm -f work*.cf