From 5b94a4294fed05dbd338f8484af06f8cc2151ac3 Mon Sep 17 00:00:00 2001 From: matt Date: Sat, 4 Apr 2009 01:14:42 +0000 Subject: copied over from other eth core git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10761 221aa14e-8319-0410-a670-987f0aec2ac5 --- simple_gemac/miim/eth_clockgen.v | 141 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 simple_gemac/miim/eth_clockgen.v (limited to 'simple_gemac/miim/eth_clockgen.v') diff --git a/simple_gemac/miim/eth_clockgen.v b/simple_gemac/miim/eth_clockgen.v new file mode 100644 index 000000000..9da732f7f --- /dev/null +++ b/simple_gemac/miim/eth_clockgen.v @@ -0,0 +1,141 @@ +////////////////////////////////////////////////////////////////////// +//// //// +//// eth_clockgen.v //// +//// //// +//// This file is part of the Ethernet IP core project //// +//// http://www.opencores.org/projects/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: eth_clockgen.v,v $ +// Revision 1.2 2005/12/13 12:54:49 maverickist +// first simulation passed +// +// Revision 1.1.1.1 2005/12/13 01:51:45 Administrator +// no message +// +// Revision 1.2 2005/04/27 15:58:45 Administrator +// no message +// +// Revision 1.1.1.1 2004/12/15 06:38:54 Administrator +// no message +// +// 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 22:28:55 mohor +// This files (MIIM) are fully working. They were thoroughly tested. The testbench is not updated. +// +// + +module eth_clockgen(Clk, Reset, Divider, MdcEn, MdcEn_n, Mdc); + +//parameter Tp=1; + +input Clk; // Input clock (Host clock) +input Reset; // Reset signal +input [7:0] Divider; // Divider (input clock will be divided by the Divider[7:0]) + +output Mdc; // Output clock +output MdcEn; // Enable signal is asserted for one Clk period before Mdc rises. +output MdcEn_n; // Enable signal is asserted for one Clk period before Mdc falls. + +reg Mdc; +reg [7:0] Counter; + +wire CountEq0; +wire [7:0] CounterPreset; +wire [7:0] TempDivider; + + +assign TempDivider[7:0] = (Divider[7:0]<2)? 8'h02 : Divider[7:0]; // If smaller than 2 +assign CounterPreset[7:0] = (TempDivider[7:0]>>1) -1; // We are counting half of period + + +// Counter counts half period +always @ (posedge Clk or posedge Reset) +begin + if(Reset) + Counter[7:0] <= 8'h1; + else + begin + if(CountEq0) + begin + Counter[7:0] <= CounterPreset[7:0]; + end + else + Counter[7:0] <= Counter - 8'h1; + end +end + + +// Mdc is asserted every other half period +always @ (posedge Clk or posedge Reset) +begin + if(Reset) + Mdc <= 1'b0; + else + begin + if(CountEq0) + Mdc <= ~Mdc; + end +end + + +assign CountEq0 = Counter == 8'h0; +assign MdcEn = CountEq0 & ~Mdc; +assign MdcEn_n = CountEq0 & Mdc; + +endmodule + + -- cgit v1.2.3