//
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//
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// Copyright (c) 2004 Guy Hutchison (ghutchis@opencores.org)
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// Copyright (c) 2004 Guy Hutchison (ghutchis@opencores.org)
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//
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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// Software is furnished to do so, subject to the following conditions:
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//
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//
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// The above copyright notice and this permission notice shall be included
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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// in all copies or substantial portions of the Software.
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//
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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// Simple wrapper for a clock synchronizer
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// Simple wrapper for a clock synchronizer
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//
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//
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// The following code can (should) be replaced with metastability-hardened
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// The following code can (should) be replaced with metastability-hardened
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// flops from your technology library.
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// flops from your technology library.
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module sync2
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module sync2
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( input clk,
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( input clk,
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input data_in,
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input data_in,
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output data_out );
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output data_out );
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reg sync_ff1, sync_ff2;
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reg sync_ff1, sync_ff2;
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always @(posedge clk)
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always @(posedge clk)
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begin
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begin
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sync_ff1 <= #1 data_in;
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sync_ff1 <= #1 data_in;
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sync_ff2 <= #1 sync_ff1;
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sync_ff2 <= #1 sync_ff1;
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end
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end
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assign data_out = sync_ff2;
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assign data_out = sync_ff2;
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endmodule // sync2
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endmodule // sync2
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