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authorClifford Wolf <clifford@clifford.at>2013-01-05 11:13:26 +0100
committerClifford Wolf <clifford@clifford.at>2013-01-05 11:13:26 +0100
commit7764d0ba1dcf064ae487ee985c43083a0909e7f4 (patch)
tree18c05b8729df381af71b707748ce1d605e0df764 /tests/openmsp430/rtl/omsp_sync_cell.v
initial import
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+//----------------------------------------------------------------------------
+// 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
+