tests/asicworld/code_hdl_models_lfsr.v

   1 //-----------------------------------------------------
   2 // Design Name : lfsr
   3 // File Name   : lfsr.v
   4 // Function    : Linear feedback shift register
   5 // Coder       : Deepak Kumar Tala
   6 //-----------------------------------------------------
   7 module lfsr    (
   8 out             ,  // Output of the counter
   9 enable          ,  // Enable  for counter
  10 clk             ,  // clock input
  11 reset              // reset input
  12 );
  13
  14 //----------Output Ports--------------
  15 output [7:0] out;
  16 //------------Input Ports--------------
  17 input enable, clk, reset;
  18 //------------Internal Variables--------
  19 reg [7:0] out;
  20 wire        linear_feedback;
  21
  22 //-------------Code Starts Here-------
  23 assign linear_feedback = !(out[7] ^ out[3]);
  24
  25 always @(posedge clk)
  26 if (reset) begin // active high reset
  27   out <= 8'b0 ;
  28 end else if (enable) begin
  29   out <= {out[6],out[5],
  30           out[4],out[3],
  31           out[2],out[1],
  32           out[0], linear_feedback};
  33 end
  34
  35 endmodule // End Of Module counter