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

////                                                              ////

////  eth_outputcontrol.v                                         ////

////                                                              ////

////  This file is part of the Ethernet IP core project           ////

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

////                                                              ////

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

////      - Igor Mohor (igorM@opencores.org)                      ////

////                                                              ////

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

////  file.                                                       ////

////                                                              ////

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

////                                                              ////

//// Copyright (C) 2001 Authors                                   ////

////                                                              ////

//// 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 $

// Revision 1.1  2001/07/30 21:23:42  mohor

// Directory structure changed. Files checked and joind together.

//

// Revision 1.3  2001/06/01 22:28:56  mohor

// This files (MIIM) are fully working. They were thoroughly tested. The testbench is not updated.

//

//

`include "eth_timescale.v"

module eth_outputcontrol(Clk, Reset, InProgress, ShiftedBit, BitCounter, WriteOp, NoPre, MdcEn_n, Mdo, MdoEn);

parameter Tp = 1;

input         Clk;                // Host Clock

input         Reset;              // General Reset

input         WriteOp;            // Write Operation Latch (When asserted, write operation is in progress)

input         NoPre;              // No Preamble (no 32-bit preamble)

input         InProgress;         // Operation in progress

input         ShiftedBit;         // This bit is output of the shift register and is connected to the Mdo signal

input   [6:0] BitCounter;         // Bit Counter

input         MdcEn_n;            // MII Management Data Clock Enable signal is asserted for one Clk period before Mdc falls.

output        Mdo;                // MII Management Data Output

output        MdoEn;              // MII Management Data Output Enable

wire          SerialEn;

reg           MdoEn_2d;

reg           MdoEn_d;

reg           MdoEn;

reg           Mdo_2d;

reg           Mdo_d;

reg           Mdo;                // MII Management Data Output

// Generation of the Serial Enable signal (enables the serialization of the data)

assign SerialEn =  WriteOp & InProgress & ( BitCounter>31 | ( ( BitCounter == 0 ) & NoPre ) )

                | ~WriteOp & InProgress & (( BitCounter>31 & BitCounter<46 ) | ( ( BitCounter == 0 ) & NoPre )); // igor !!!  ali je tu res <46. To je veljalo, ko sem imel se >31 in napako 32 preamble bitov

// Generation of the MdoEn signal

always @ (posedge Clk or posedge Reset)

begin

  if(Reset)

    begin

      MdoEn_2d <= #Tp 1'b0;

      MdoEn_d <= #Tp 1'b0;

      MdoEn <= #Tp 1'b0;

    end

  else

    begin

      if(MdcEn_n)

        begin

          MdoEn_2d <= #Tp SerialEn | InProgress & BitCounter<32;

          MdoEn_d <= #Tp MdoEn_2d;

          MdoEn <= #Tp MdoEn_d;

        end

    end

end

// Generation of the Mdo signal.

always @ (posedge Clk or posedge Reset)

begin

  if(Reset)

    begin

      Mdo_2d <= #Tp 1'b0;

      Mdo_d <= #Tp 1'b0;

      Mdo <= #Tp 1'b0;

    end

  else

    begin

      if(MdcEn_n)

        begin

          Mdo_2d <= #Tp ~SerialEn & BitCounter<32;

          Mdo_d <= #Tp ShiftedBit | Mdo_2d;

          Mdo <= #Tp Mdo_d;

        end

    end

end

endmodule