[128] | 1 | //////////////////////////////////////////////////////////////////////
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| 2 | //// ////
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| 3 | //// can_crc.v ////
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| 4 | //// ////
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| 5 | //// ////
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| 6 | //// This file is part of the CAN Protocol Controller ////
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| 7 | //// http://www.opencores.org/projects/can/ ////
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| 8 | //// ////
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| 9 | //// ////
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| 10 | //// Author(s): ////
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| 11 | //// Igor Mohor ////
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| 12 | //// igorm@opencores.org ////
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| 13 | //// ////
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| 14 | //// ////
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| 15 | //// All additional information is available in the README.txt ////
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| 16 | //// file. ////
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| 17 | //// ////
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| 18 | //////////////////////////////////////////////////////////////////////
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| 19 | //// ////
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| 20 | //// Copyright (C) 2002, 2003, 2004 Authors ////
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| 21 | //// ////
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| 22 | //// This source file may be used and distributed without ////
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| 23 | //// restriction provided that this copyright statement is not ////
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| 24 | //// removed from the file and that any derivative work contains ////
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| 25 | //// the original copyright notice and the associated disclaimer. ////
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| 26 | //// ////
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| 27 | //// This source file is free software; you can redistribute it ////
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| 28 | //// and/or modify it under the terms of the GNU Lesser General ////
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| 29 | //// Public License as published by the Free Software Foundation; ////
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| 30 | //// either version 2.1 of the License, or (at your option) any ////
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| 31 | //// later version. ////
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| 32 | //// ////
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| 33 | //// This source is distributed in the hope that it will be ////
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| 34 | //// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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| 35 | //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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| 36 | //// PURPOSE. See the GNU Lesser General Public License for more ////
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| 37 | //// details. ////
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| 38 | //// ////
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| 39 | //// You should have received a copy of the GNU Lesser General ////
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| 40 | //// Public License along with this source; if not, download it ////
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| 41 | //// from http://www.opencores.org/lgpl.shtml ////
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| 42 | //// ////
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| 43 | //// The CAN protocol is developed by Robert Bosch GmbH and ////
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| 44 | //// protected by patents. Anybody who wants to implement this ////
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| 45 | //// CAN IP core on silicon has to obtain a CAN protocol license ////
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| 46 | //// from Bosch. ////
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| 47 | //// ////
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| 48 | //////////////////////////////////////////////////////////////////////
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| 49 | //
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| 50 | // CVS Revision History
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| 51 | //
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| 52 | // $Log: can_crc.v,v $
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| 53 | // Revision 1.5 2004/02/08 14:25:57 mohor
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| 54 | // Header changed.
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| 55 | //
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| 56 | // Revision 1.4 2003/07/16 13:16:51 mohor
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| 57 | // Fixed according to the linter.
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| 58 | //
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| 59 | // Revision 1.3 2003/02/10 16:02:11 mohor
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| 60 | // CAN is working according to the specification. WB interface and more
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| 61 | // registers (status, IRQ, ...) needs to be added.
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| 62 | //
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| 63 | // Revision 1.2 2003/02/09 02:24:33 mohor
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| 64 | // Bosch license warning added. Error counters finished. Overload frames
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| 65 | // still need to be fixed.
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| 66 | //
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| 67 | // Revision 1.1 2003/01/08 02:10:54 mohor
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| 68 | // Acceptance filter added.
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| 69 | //
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| 70 | //
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| 71 | //
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| 72 | //
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| 73 |
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| 74 | // synopsys translate_off
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| 75 | `include "timescale.v"
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| 76 | // synopsys translate_on
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| 77 |
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| 78 | module can_crc (clk, data, enable, initialize, crc);
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| 79 |
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| 80 |
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| 81 | parameter Tp = 1;
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| 82 |
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| 83 | input clk;
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| 84 | input data;
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| 85 | input enable;
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| 86 | input initialize;
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| 87 |
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| 88 | output [14:0] crc;
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| 89 |
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| 90 | reg [14:0] crc;
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| 91 |
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| 92 | wire crc_next;
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| 93 | wire [14:0] crc_tmp;
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| 94 |
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| 95 |
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| 96 | assign crc_next = data ^ crc[14];
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| 97 | assign crc_tmp = {crc[13:0], 1'b0};
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| 98 |
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| 99 | always @ (posedge clk)
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| 100 | begin
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| 101 | if(initialize)
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| 102 | crc <= #Tp 15'h0;
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| 103 | else if (enable)
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| 104 | begin
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| 105 | if (crc_next)
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| 106 | crc <= #Tp crc_tmp ^ 15'h4599;
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| 107 | else
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| 108 | crc <= #Tp crc_tmp;
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| 109 | end
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| 110 | end
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| 111 |
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| 112 |
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| 113 | endmodule
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