diff --git a/5_clock_block/rtl/chip_if.sv b/5_clock_block/rtl/chip_if.sv
index eba5e6e..c96bcf2 100644
--- a/5_clock_block/rtl/chip_if.sv
+++ b/5_clock_block/rtl/chip_if.sv
@@ -20,20 +20,22 @@ interface chip_if(input bit clk);
     logic cnt_en;
     logic clear;
     logic [7:0] cnt;
-    
-    task init;
-        rst_n = 0;
-        cnt_en = 0;
-        clear = 0;
-    endtask
 
     clocking ck_p @(posedge clk);
+        default input #1ns output #1ns;
         output rst_n;
         output cnt_en;
         output clear;
         input cnt;
     endclocking
 
+    task init;
+        ck_p.rst_n <= 0;
+        ck_p.cnt_en <= 0;
+        ck_p.clear <= 0;
+        @ck_p;
+    endtask
+
     modport DUT(clocking ck_p);
         
 endinterface
diff --git a/5_clock_block/rtl/tb.sv b/5_clock_block/rtl/tb.sv
index 1af2a9f..9e74f4a 100644
--- a/5_clock_block/rtl/tb.sv
+++ b/5_clock_block/rtl/tb.sv
@@ -34,6 +34,14 @@ module testbench;
         @co_if.ck_p;
         $display("cnt = %d", co_if.ck_p.cnt);
       end
+      @co_if.ck_p;
+      co_if.ck_p.clear <= 1;
+      @co_if.ck_p;
+      co_if.ck_p.clear <= 0;
+      for(int i=0; i<10; i++) begin
+        @co_if.ck_p;
+        $display("cnt = %d", co_if.ck_p.cnt);
+      end
       $finish(2);
     end
 
diff --git a/5_clock_block/signal.rc b/5_clock_block/signal.rc
index eaabc99..de6560c 100644
--- a/5_clock_block/signal.rc
+++ b/5_clock_block/signal.rc
@@ -2,7 +2,7 @@ Magic 271485
 Revision Verdi_O-2018.09-SP2
 
 ; Window Layout <x> <y> <width> <height> <signalwidth> <valuewidth>
-viewPort 0 27 1850 380 212 65
+viewPort 0 27 1850 384 212 65
 
 ; File list:
 ; openDirFile [-d delimiter] [-s time_offset] [-rf auto_bus_rule_file] path_name file_name
@@ -16,8 +16,8 @@ signalSpacing 5
 
 ; windowTimeUnit is used for zoom, cursor & marker
 ; waveform viewport range
-zoom 0.000000 471.232836
-cursor 0.000000
+zoom 0.000000 247450.000000
+cursor 25000.000000
 marker 0.000000
 
 ; user define markers
@@ -51,12 +51,12 @@ addSignal -h 15 /testbench/u0_dut/clk
 addSignal -h 15 -holdScope rst_n
 addSignal -h 15 -holdScope cnt_en
 addSignal -h 15 -holdScope clear
-addSignal -h 15 -holdScope cnt[7:0]
+addSignal -h 15 -UNSIGNED -UDEC -holdScope cnt[7:0]
 addGroup "G2"
 addSignal -h 15 /testbench/co_if/ck_p/rst_n
 addSignal -h 15 -holdScope cnt_en
 addSignal -h 15 -holdScope clear
-addSignal -h 15 -holdScope cnt[7:0]
+addSignal -h 15 -UNSIGNED -UDEC -holdScope cnt[7:0]
 addGroup "G3"
 
 ; getSignalForm Scope Hierarchy Status