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[/] [ethmac/] [trunk/] [rtl/] [verilog/] [eth_shiftreg.v] - Rev 355
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////////////////////////////////////////////////////////////////////// //// //// //// eth_shiftreg.v //// //// //// //// This file is part of the Ethernet IP core project //// //// http://www.opencores.org/project,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 1.5 2002/08/14 18:16:59 mohor // LinkFail signal was not latching appropriate bit. // // Revision 1.4 2002/03/02 21:06:01 mohor // LinkFail signal was not latching appropriate bit. // // Revision 1.3 2002/01/23 10:28:16 mohor // Link in the header changed. // // Revision 1.2 2001/10/19 08:43:51 mohor // eth_timescale.v changed to timescale.v This is done because of the // simulation of the few cores in a one joined project. // // Revision 1.1 2001/08/06 14:44:29 mohor // A define FPGA added to select between Artisan RAM (for ASIC) and Block Ram (For Virtex). // Include files fixed to contain no path. // File names and module names changed ta have a eth_ prologue in the name. // File eth_timescale.v is used to define timescale // All pin names on the top module are changed to contain _I, _O or _OE at the end. // Bidirectional signal MDIO is changed to three signals (Mdc_O, Mdi_I, Mdo_O // and Mdo_OE. The bidirectional signal must be created on the top level. This // is done due to the ASIC tools. // // 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 "timescale.v" module eth_shiftreg(Clk, Reset, MdcEn_n, Mdi, Fiad, Rgad, CtrlData, WriteOp, ByteSelect, LatchByte, ShiftedBit, Prsd, LinkFail); input Clk; // Input clock (Host clock) input Reset; // Reset signal input MdcEn_n; // Enable signal is asserted for one Clk period before Mdc falls. input Mdi; // MII input data input [4:0] Fiad; // PHY address input [4:0] Rgad; // Register address (within the selected PHY) input [15:0]CtrlData; // Control data (data to be written to the PHY) input WriteOp; // The current operation is a PHY register write operation input [3:0] ByteSelect; // Byte select input [1:0] LatchByte; // Byte select for latching (read operation) output ShiftedBit; // Bit shifted out of the shift register output[15:0]Prsd; // Read Status Data (data read from the PHY) output LinkFail; // Link Integrity Signal reg [7:0] ShiftReg; // Shift register for shifting the data in and out reg [15:0]Prsd; reg LinkFail; // ShiftReg[7:0] :: Shift Register Data always @ (posedge Clk or posedge Reset) begin if(Reset) begin ShiftReg[7:0] <= 8'h0; Prsd[15:0] <= 16'h0; LinkFail <= 1'b0; end else begin if(MdcEn_n) begin if(|ByteSelect) begin /* verilator lint_off CASEINCOMPLETE */ case (ByteSelect[3:0]) // synopsys parallel_case full_case 4'h1 : ShiftReg[7:0] <= {2'b01, ~WriteOp, WriteOp, Fiad[4:1]}; 4'h2 : ShiftReg[7:0] <= {Fiad[0], Rgad[4:0], 2'b10}; 4'h4 : ShiftReg[7:0] <= CtrlData[15:8]; 4'h8 : ShiftReg[7:0] <= CtrlData[7:0]; endcase // case (ByteSelect[3:0]) /* verilator lint_on CASEINCOMPLETE */ end else begin ShiftReg[7:0] <= {ShiftReg[6:0], Mdi}; if(LatchByte[0]) begin Prsd[7:0] <= {ShiftReg[6:0], Mdi}; if(Rgad == 5'h01) LinkFail <= ~ShiftReg[1]; // this is bit [2], because it is not shifted yet end else begin if(LatchByte[1]) Prsd[15:8] <= {ShiftReg[6:0], Mdi}; end end end end end assign ShiftedBit = ShiftReg[7]; endmodule