155 lines
6.5 KiB
Verilog
155 lines
6.5 KiB
Verilog
//////////////////////////////////////////////////////////////////////
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//// ////
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//// eth_shiftreg.v ////
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//// ////
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//// This file is part of the Ethernet IP core project ////
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//// http://www.opencores.org/projects/ethmac/ ////
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//// ////
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//// Author(s): ////
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//// - Igor Mohor (igorM@opencores.org) ////
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//// ////
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//// All additional information is avaliable in the Readme.txt ////
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//// file. ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// Copyright (C) 2001 Authors ////
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//// ////
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//// This source file may be used and distributed without ////
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//// restriction provided that this copyright statement is not ////
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//// removed from the file and that any derivative work contains ////
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//// the original copyright notice and the associated disclaimer. ////
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//// ////
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//// This source file is free software; you can redistribute it ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// later version. ////
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//// ////
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//// This source is distributed in the hope that it will be ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// details. ////
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//// ////
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//// You should have received a copy of the GNU Lesser General ////
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//// Public License along with this source; if not, download it ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//
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// CVS Revision History
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//
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// $Log: eth_shiftreg.v,v $
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// Revision 1.6 2005/03/08 14:45:09 igorm
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// Case statement improved for synthesys.
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//
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// Revision 1.5 2002/08/14 18:16:59 mohor
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// LinkFail signal was not latching appropriate bit.
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//
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// Revision 1.4 2002/03/02 21:06:01 mohor
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// LinkFail signal was not latching appropriate bit.
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//
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// Revision 1.3 2002/01/23 10:28:16 mohor
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// Link in the header changed.
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//
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// Revision 1.2 2001/10/19 08:43:51 mohor
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// eth_timescale.v changed to timescale.v This is done because of the
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// simulation of the few cores in a one joined project.
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//
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// Revision 1.1 2001/08/06 14:44:29 mohor
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// A define FPGA added to select between Artisan RAM (for ASIC) and Block Ram (For Virtex).
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// Include files fixed to contain no path.
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// File names and module names changed ta have a eth_ prologue in the name.
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// File eth_timescale.v is used to define timescale
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// All pin names on the top module are changed to contain _I, _O or _OE at the end.
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// Bidirectional signal MDIO is changed to three signals (Mdc_O, Mdi_I, Mdo_O
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// and Mdo_OE. The bidirectional signal must be created on the top level. This
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// is done due to the ASIC tools.
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//
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// Revision 1.1 2001/07/30 21:23:42 mohor
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// Directory structure changed. Files checked and joind together.
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//
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// Revision 1.3 2001/06/01 22:28:56 mohor
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// This files (MIIM) are fully working. They were thoroughly tested. The testbench is not updated.
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//
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//
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`include "timescale.v"
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module eth_shiftreg(Clk, Reset, MdcEn_n, Mdi, Fiad, Rgad, CtrlData, WriteOp, ByteSelect,
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LatchByte, ShiftedBit, Prsd, LinkFail);
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parameter Tp=1;
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input Clk; // Input clock (Host clock)
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input Reset; // Reset signal
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input MdcEn_n; // Enable signal is asserted for one Clk period before Mdc falls.
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input Mdi; // MII input data
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input [4:0] Fiad; // PHY address
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input [4:0] Rgad; // Register address (within the selected PHY)
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input [15:0]CtrlData; // Control data (data to be written to the PHY)
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input WriteOp; // The current operation is a PHY register write operation
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input [3:0] ByteSelect; // Byte select
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input [1:0] LatchByte; // Byte select for latching (read operation)
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output ShiftedBit; // Bit shifted out of the shift register
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output[15:0]Prsd; // Read Status Data (data read from the PHY)
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output LinkFail; // Link Integrity Signal
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reg [7:0] ShiftReg; // Shift register for shifting the data in and out
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reg [15:0]Prsd;
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reg LinkFail;
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// ShiftReg[7:0] :: Shift Register Data
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always @ (posedge Clk or posedge Reset)
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begin
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if(Reset)
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begin
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ShiftReg[7:0] <= #Tp 8'h0;
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Prsd[15:0] <= #Tp 16'h0;
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LinkFail <= #Tp 1'b0;
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end
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else
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begin
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if(MdcEn_n)
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begin
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if(|ByteSelect)
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begin
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case (ByteSelect[3:0]) // synopsys parallel_case full_case
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4'h1 : ShiftReg[7:0] <= #Tp {2'b01, ~WriteOp, WriteOp, Fiad[4:1]};
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4'h2 : ShiftReg[7:0] <= #Tp {Fiad[0], Rgad[4:0], 2'b10};
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4'h4 : ShiftReg[7:0] <= #Tp CtrlData[15:8];
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4'h8 : ShiftReg[7:0] <= #Tp CtrlData[7:0];
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endcase
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end
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else
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begin
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ShiftReg[7:0] <= #Tp {ShiftReg[6:0], Mdi};
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if(LatchByte[0])
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begin
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Prsd[7:0] <= #Tp {ShiftReg[6:0], Mdi};
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if(Rgad == 5'h01)
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LinkFail <= #Tp ~ShiftReg[1]; // this is bit [2], because it is not shifted yet
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end
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else
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begin
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if(LatchByte[1])
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Prsd[15:8] <= #Tp {ShiftReg[6:0], Mdi};
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end
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end
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end
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end
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end
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assign ShiftedBit = ShiftReg[7];
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endmodule
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