| 40a1f26c |
1 | ////////////////////////////////////////////////////////////////////// |
| 2 | //// //// |
| 3 | //// File name "perr_en_crit.v" //// |
| 4 | //// //// |
| 5 | //// This file is part of the "PCI bridge" project //// |
| 6 | //// http://www.opencores.org/cores/pci/ //// |
| 7 | //// //// |
| 8 | //// Author(s): //// |
| 9 | //// - Miha Dolenc (mihad@opencores.org) //// |
| 10 | //// //// |
| 11 | //// All additional information is avaliable in the README //// |
| 12 | //// file. //// |
| 13 | //// //// |
| 14 | //// //// |
| 15 | ////////////////////////////////////////////////////////////////////// |
| 16 | //// //// |
| 17 | //// Copyright (C) 2000 Miha Dolenc, mihad@opencores.org //// |
| 18 | //// //// |
| 19 | //// This source file may be used and distributed without //// |
| 20 | //// restriction provided that this copyright statement is not //// |
| 21 | //// removed from the file and that any derivative work contains //// |
| 22 | //// the original copyright notice and the associated disclaimer. //// |
| 23 | //// //// |
| 24 | //// This source file is free software; you can redistribute it //// |
| 25 | //// and/or modify it under the terms of the GNU Lesser General //// |
| 26 | //// Public License as published by the Free Software Foundation; //// |
| 27 | //// either version 2.1 of the License, or (at your option) any //// |
| 28 | //// later version. //// |
| 29 | //// //// |
| 30 | //// This source is distributed in the hope that it will be //// |
| 31 | //// useful, but WITHOUT ANY WARRANTY; without even the implied //// |
| 32 | //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR //// |
| 33 | //// PURPOSE. See the GNU Lesser General Public License for more //// |
| 34 | //// details. //// |
| 35 | //// //// |
| 36 | //// You should have received a copy of the GNU Lesser General //// |
| 37 | //// Public License along with this source; if not, download it //// |
| 38 | //// from http://www.opencores.org/lgpl.shtml //// |
| 39 | //// //// |
| 40 | ////////////////////////////////////////////////////////////////////// |
| 41 | // |
| 42 | // CVS Revision History |
| 43 | // |
| 44 | // $Log: pci_perr_en_crit.v,v $ |
| 45 | // Revision 1.1 2007-03-20 17:50:56 sithglan |
| 46 | // add shit |
| 47 | // |
| 48 | // Revision 1.2 2003/02/13 18:26:33 mihad |
| 49 | // Cleaned up the code. No functional changes. |
| 50 | // |
| 51 | // Revision 1.1 2003/01/27 16:49:31 mihad |
| 52 | // Changed module and file names. Updated scripts accordingly. FIFO synchronizations changed. |
| 53 | // |
| 54 | // Revision 1.3 2002/02/01 15:25:13 mihad |
| 55 | // Repaired a few bugs, updated specification, added test bench files and design document |
| 56 | // |
| 57 | // Revision 1.2 2001/10/05 08:14:30 mihad |
| 58 | // Updated all files with inclusion of timescale file for simulation purposes. |
| 59 | // |
| 60 | // Revision 1.1.1.1 2001/10/02 15:33:47 mihad |
| 61 | // New project directory structure |
| 62 | // |
| 63 | // |
| 64 | |
| 65 | // module is used to separate logic which uses criticaly constrained inputs from slower logic. |
| 66 | // It is used to synthesize critical timing logic separately with faster cells or without optimization |
| 67 | |
| 68 | // This one is used in parity generator/checker for parity error (PERR#) output enable driving |
| 69 | |
| 70 | // synopsys translate_off |
| 71 | `include "timescale.v" |
| 72 | // synopsys translate_on |
| 73 | |
| 74 | module pci_perr_en_crit |
| 75 | ( |
| 76 | reset_in, |
| 77 | clk_in, |
| 78 | perr_en_out, |
| 79 | perr_en_reg_out, |
| 80 | non_critical_par_in, |
| 81 | pci_par_in, |
| 82 | perr_generate_in, |
| 83 | par_err_response_in |
| 84 | ) ; |
| 85 | output perr_en_out, |
| 86 | perr_en_reg_out ; |
| 87 | |
| 88 | input reset_in, |
| 89 | clk_in, |
| 90 | non_critical_par_in, |
| 91 | pci_par_in, |
| 92 | perr_generate_in, |
| 93 | par_err_response_in ; |
| 94 | |
| 95 | wire perr = par_err_response_in && perr_generate_in && ( non_critical_par_in ^ pci_par_in ) ; |
| 96 | |
| 97 | // PERR# is enabled for two clocks after parity error is detected - one cycle active, another inactive |
| 98 | reg perr_en_reg_out ; |
| 99 | always@(posedge reset_in or posedge clk_in) |
| 100 | begin |
| 101 | if ( reset_in ) |
| 102 | perr_en_reg_out <= #1 1'b0 ; |
| 103 | else |
| 104 | perr_en_reg_out <= #1 perr ; |
| 105 | end |
| 106 | |
| 107 | assign perr_en_out = perr || perr_en_reg_out ; |
| 108 | |
| 109 | endmodule |
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