diff --git a/src/ft2004_top.v b/src/ft2004_top.v
index 92028b3..f8f120a 100644
--- a/src/ft2004_top.v
+++ b/src/ft2004_top.v
@@ -106,10 +106,6 @@ assign gpio1_b7 = ft_gpio1_b7;
 assign gpio0_b6 = ft_gpio0_b6;
 assign gpio0_b7 = ft_gpio0_b7;
 
-localparam CPU_STATE_IDLE = 2'b00, 
-           CPU_STATE_RUN  = 2'b01,
-           CPU_STATE_RST  = 2'b10;
-           
 reg clk_1k = 1'b0;
 
 // divide to 1K clock
@@ -148,8 +144,13 @@ key_delay reset_key(
     .clk_1K(clk_1k),
     .keyout(rst_key));
 
+// cpu state transition
 reg power_on = 1'b0;
 
+localparam CPU_STATE_IDLE = 2'b00, 
+           CPU_STATE_RUN  = 2'b01,
+           CPU_STATE_RST  = 2'b10;
+           
 reg [1:0] state      = CPU_STATE_IDLE;
 reg [1:0] next_state = CPU_STATE_IDLE;
 
@@ -158,6 +159,11 @@ reg [3:0] cmd_b, cmd_q, cmd_val;
 always @(posedge clk_33m) begin
     cmd_b <= ctr_cnt;
     cmd_q <= cmd_b;
+
+    if (cmd_b == 4'b0000)
+        cmd_val <= cmd_q;
+    else
+        cmd_val <= 4'b0000;
 end
 
 always @(posedge clk_33m) begin
@@ -200,10 +206,6 @@ always @(*) begin
                 timen_flag = 1'b1;
         end
         CPU_STATE_RUN: begin
-            if (!cmd_b)
-                cmd_val = cmd_q;
-            else
-                cmd_val = 4'b0000;
             case (cmd_val)
                 4'b0001: begin // bios booting: S3_OK_Clear
                     gpio0_a1   = 1'b1;
@@ -226,9 +228,10 @@ always @(*) begin
     endcase
 end
 
-// enable various votage groups.
+//
+// enable various voltage groups.
 // if `time_en == 1'b0, mills_count always equal to `0`
-// so power pins will stable.
+// so power pins will stable at most time.
 always @(posedge clk_1k) begin
     if (!power_on) begin
         case(mills_count)