initial import

tests/openmsp430/rtl/omsp_sync_cell.v

@@ -0,0 +1,80 @@
+//----------------------------------------------------------------------------
+// Copyright (C) 2009 , Olivier Girard
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//     * 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
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+// THE POSSIBILITY OF SUCH DAMAGE
+//
+//----------------------------------------------------------------------------
+//
+// *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
+