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[/] [qaz_libs/] [trunk/] [BFM/] [src/] [clock/] [recover_clock.v] - Rev 34

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// --------------------------------------------------------------------
//
// --------------------------------------------------------------------
 
`timescale 1ps/1ps
 
 
module
  recover_clock
  #(
    parameter PROFILE_COUNT   = 20
  )
  (
    input       in,
 
    output reg  clock
  );
 
  time  in_time_buffer;
  time  clock_period_buffer;
  time  clock_out_period = 1000000;
 
  integer count = 0;
 
  // --------------------------------------------------------------------
  //
  reg internal_clock;
 
  initial
    begin
 
      internal_clock <= 1'bx;
 
      wait( in === 0 );
 
      repeat( PROFILE_COUNT )
        begin
 
          @( posedge in );
          in_time_buffer  = $time;
          @( negedge in );
 
          clock_period_buffer = $time - in_time_buffer;
 
          if( clock_period_buffer < clock_out_period )
            clock_out_period = clock_period_buffer;
 
          count = count + 1;
 
        end
 
      $display( "-#- %16.t | recover_clock: period (in sim time) = %t", $time, clock_out_period );
 
      @( posedge in )
        internal_clock <= 1'b1;
 
      forever
        #(clock_out_period/2) internal_clock <= ~internal_clock;
 
    end
 
 
  // --------------------------------------------------------------------
  //
  time  delta = 0;
  time  delta_buffer = 0;
 
  always @( posedge internal_clock)
    delta_buffer <= $time;
 
  always @( posedge in)
    if( internal_clock !== 1'bx )
      delta <= ($time - delta_buffer) %  clock_period_buffer;
 
 
  // --------------------------------------------------------------------
  //
  always @( * )
    clock = #(delta) internal_clock;
 
 
endmodule
 
 

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