+//////////////////////////////////////////////////////////////////////
+//// ////
+//// eth_rxstatem.v ////
+//// ////
+//// This file is part of the Ethernet IP core project ////
+//// http://www.opencores.org/projects/ethmac/ ////
+//// ////
+//// Author(s): ////
+//// - Igor Mohor (igorM@opencores.org) ////
+//// - Novan Hartadi (novan@vlsi.itb.ac.id) ////
+//// - Mahmud Galela (mgalela@vlsi.itb.ac.id) ////
+//// ////
+//// 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_rxstatem.v,v $
+// Revision 1.1 2007-03-20 17:50:56 sithglan
+// add shit
+//
+// Revision 1.6 2002/11/13 22:28:26 tadejm
+// StartIdle state changed (not important the size of the packet).
+// StartData1 activates only while ByteCnt is smaller than the MaxFrame.
+//
+// Revision 1.5 2002/01/23 10:28:16 mohor
+// Link in the header changed.
+//
+// Revision 1.4 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 1.3 2001/10/18 12:07:11 mohor
+// Status signals changed, Adress decoding changed, interrupt controller
+// added.
+//
+// Revision 1.2 2001/09/11 14:17:00 mohor
+// Few little NCSIM warnings fixed.
+//
+// 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 1.2 2001/07/03 12:55:41 mohor
+// Minor changes because of the synthesys warnings.
+//
+//
+// Revision 1.1 2001/06/27 21:26:19 mohor
+// Initial release of the RxEthMAC module.
+//
+//
+//
+//
+
+
+`include "timescale.v"
+
+
+module eth_rxstatem (MRxClk, Reset, MRxDV, ByteCntEq0, ByteCntGreat2, Transmitting, MRxDEq5, MRxDEqD,
+ IFGCounterEq24, ByteCntMaxFrame, StateData, StateIdle, StatePreamble, StateSFD,
+ StateDrop
+ );
+
+parameter Tp = 1;
+
+input MRxClk;
+input Reset;
+input MRxDV;
+input ByteCntEq0;
+input ByteCntGreat2;
+input MRxDEq5;
+input Transmitting;
+input MRxDEqD;
+input IFGCounterEq24;
+input ByteCntMaxFrame;
+
+output [1:0] StateData;
+output StateIdle;
+output StateDrop;
+output StatePreamble;
+output StateSFD;
+
+reg StateData0;
+reg StateData1;
+reg StateIdle;
+reg StateDrop;
+reg StatePreamble;
+reg StateSFD;
+
+wire StartIdle;
+wire StartDrop;
+wire StartData0;
+wire StartData1;
+wire StartPreamble;
+wire StartSFD;
+
+
+// Defining the next state
+assign StartIdle = ~MRxDV & (StateDrop | StatePreamble | StateSFD | (|StateData));
+
+assign StartPreamble = MRxDV & ~MRxDEq5 & (StateIdle & ~Transmitting);
+
+assign StartSFD = MRxDV & MRxDEq5 & (StateIdle & ~Transmitting | StatePreamble);
+
+assign StartData0 = MRxDV & (StateSFD & MRxDEqD & IFGCounterEq24 | StateData1);
+
+assign StartData1 = MRxDV & StateData0 & (~ByteCntMaxFrame);
+
+assign StartDrop = MRxDV & (StateIdle & Transmitting | StateSFD & ~IFGCounterEq24 & MRxDEqD
+ | StateData0 & ByteCntMaxFrame
+ );
+
+// Rx State Machine
+always @ (posedge MRxClk or posedge Reset)
+begin
+ if(Reset)
+ begin
+ StateIdle <= #Tp 1'b0;
+ StateDrop <= #Tp 1'b1;
+ StatePreamble <= #Tp 1'b0;
+ StateSFD <= #Tp 1'b0;
+ StateData0 <= #Tp 1'b0;
+ StateData1 <= #Tp 1'b0;
+ end
+ else
+ begin
+ if(StartPreamble | StartSFD | StartDrop)
+ StateIdle <= #Tp 1'b0;
+ else
+ if(StartIdle)
+ StateIdle <= #Tp 1'b1;
+
+ if(StartIdle)
+ StateDrop <= #Tp 1'b0;
+ else
+ if(StartDrop)
+ StateDrop <= #Tp 1'b1;
+
+ if(StartSFD | StartIdle | StartDrop)
+ StatePreamble <= #Tp 1'b0;
+ else
+ if(StartPreamble)
+ StatePreamble <= #Tp 1'b1;
+
+ if(StartPreamble | StartIdle | StartData0 | StartDrop)
+ StateSFD <= #Tp 1'b0;
+ else
+ if(StartSFD)
+ StateSFD <= #Tp 1'b1;
+
+ if(StartIdle | StartData1 | StartDrop)
+ StateData0 <= #Tp 1'b0;
+ else
+ if(StartData0)
+ StateData0 <= #Tp 1'b1;
+
+ if(StartIdle | StartData0 | StartDrop)
+ StateData1 <= #Tp 1'b0;
+ else
+ if(StartData1)
+ StateData1 <= #Tp 1'b1;
+ end
+end
+
+assign StateData[1:0] = {StateData1, StateData0};
+
+endmodule