SVIncCompil/Testcases/YosysBigSim/openmsp430/rtl/omsp_sync_cell.v

//----------------------------------------------------------------------------
// Copyright (C) 2009 , Olivier Girard
//
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// modification, are permitted provided that the following conditions
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//     * Neither the name of the authors nor the names of its contributors
//       may be used to endorse or promote products derived from this software
//       without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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//
//----------------------------------------------------------------------------
//
// *File Name: omsp_sync_cell.v
// 
// *Module Description:
//                       Generic synchronizer for the openMSP430
//
// *Author(s):
//              - Olivier Girard,    olgirard@gmail.com
//
//----------------------------------------------------------------------------
// $Rev: 103 $
// $LastChangedBy: olivier.girard $
// $LastChangedDate: 2011-03-05 15:44:48 +0100 (Sat, 05 Mar 2011) $
//----------------------------------------------------------------------------

module  omsp_sync_cell (

// OUTPUTs
    data_out,                      // Synchronized data output

// INPUTs
    clk,                           // Receiving clock
    data_in,                       // Asynchronous data input
    rst                            // Receiving reset (active high)
);

// OUTPUTs
//=========
output              data_out;      // Synchronized data output

// INPUTs
//=========
input               clk;          // Receiving clock
input               data_in;      // Asynchronous data input
input               rst;          // Receiving reset (active high)


//=============================================================================
// 1)  SYNCHRONIZER
//=============================================================================

reg  [1:0] data_sync;

always @(posedge clk or posedge rst)
  if (rst) data_sync <=  2'b00;
  else     data_sync <=  {data_sync[0], data_in};

assign     data_out   =   data_sync[1];


endmodule // omsp_sync_cell