//FILE NAME: GrayCounter_2//AUTHOR:    jialiang`timescale 1ns/1nsmodule GrayCounter_2(    gray_out,    bin_addr,    enable,    rst,    clk    );      parameter   COUNTER_WIDTH = 7 ;     output   [COUNTER_WIDTH-1:0]    gray_out;  //'Gray' code count output.  output   [COUNTER_WIDTH-2:0]    bin_addr;      input                           enable;    //Count enable.  input                           rst;       //Count reset.  input                           clk;   reg      [COUNTER_WIDTH-1:0]    gray_out;  reg      [COUNTER_WIDTH-1:0]    bin;  assign  bin_addr = bin[COUNTER_WIDTH-2:0];   always @ (posedge clk or negedge rst) begin     if (!rst) begin         bin      <= 1;            gray_out <= 0;           end     else if (enable) begin         bin   <= bin + 1;         gray_out <= (bin>>1)^bin;     end   end  //end always @(posedge clk or negedge rst)    endmodule