Subversion Repositories pci

//////////////////////////////////////////////////////////////////////

////                                                              ////

////  File name: pci_target32_stop_crit.v                         ////

////                                                              ////

////  This file is part of the "PCI bridge" project               ////

////  http://www.opencores.org/cores/pci/                         ////

////                                                              ////

////  Author(s):                                                  ////

////      - Tadej Markovic, tadej@opencores.org                   ////

////                                                              ////

////  All additional information is avaliable in the README.txt   ////

////  file.                                                       ////

////                                                              ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2000 Tadej Markovic, tadej@opencores.org       ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source is distributed in the hope that it will be       ////

//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////

//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////

//// PURPOSE.  See the GNU Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

//

// module is used to separate logic which uses criticaly constrained inputs from slower logic.

// It is used to synthesize critical timing logic separately with faster cells or without optimization

`include "constants.v"

module PCI_TARGET32_STOP_CRIT

(

    stop_w,

    stop_w_frm,

    stop_w_frm_irdy,

    pci_frame_in,

    pci_irdy_in,

    pci_stop_out

);

input       stop_w ;                    // stop signal (composed without critical signals) that do not need critical inputs

input       stop_w_frm ;                // stop signal (composed without critical signals) that needs AND with critical FRAME input

input       stop_w_frm_irdy ;   // stop signal (composed without critical signals) that needs AND with critical FRAME and

                                                                // IRDY inputs

input       pci_frame_in ;              // critical constrained input signal

input           pci_irdy_in ;           // critical constrained input signal

output          pci_stop_out ;          // PCI stop output

// PCI stop output with preserved hierarchy for minimum delay!

assign  pci_stop_out = ~(stop_w || (stop_w_frm && ~pci_frame_in) || (stop_w_frm_irdy && ~pci_frame_in && ~pci_irdy_in)) ;

endmodule