+//////////////////////////////////////////////////////////////////////
+//// ////
+//// eth_transmitcontrol.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_transmitcontrol.v,v $
+// Revision 1.1 2007-03-20 17:50:56 sithglan
+// add shit
+//
+// Revision 1.6 2002/11/21 00:16:14 mohor
+// When TxUsedData and CtrlMux occur at the same time, byte counter needs
+// to be incremented by 2. Signal IncrementByteCntBy2 added for that reason.
+//
+// Revision 1.5 2002/11/19 17:37:32 mohor
+// When control frame (PAUSE) was sent, status was written in the
+// eth_wishbone module and both TXB and TXC interrupts were set. Fixed.
+// Only TXC interrupt is set.
+//
+// Revision 1.4 2002/01/23 10:28:16 mohor
+// Link in the header changed.
+//
+// Revision 1.3 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 1.2 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 1.1 2001/07/03 12:51:54 mohor
+// Initial release of the MAC Control module.
+//
+//
+//
+//
+//
+//
+
+
+`include "timescale.v"
+
+
+module eth_transmitcontrol (MTxClk, TxReset, TxUsedDataIn, TxUsedDataOut, TxDoneIn, TxAbortIn,
+ TxStartFrmIn, TPauseRq, TxUsedDataOutDetected, TxFlow, DlyCrcEn,
+ TxPauseTV, MAC, TxCtrlStartFrm, TxCtrlEndFrm, SendingCtrlFrm, CtrlMux,
+ ControlData, WillSendControlFrame, BlockTxDone
+ );
+
+parameter Tp = 1;
+
+
+input MTxClk;
+input TxReset;
+input TxUsedDataIn;
+input TxUsedDataOut;
+input TxDoneIn;
+input TxAbortIn;
+input TxStartFrmIn;
+input TPauseRq;
+input TxUsedDataOutDetected;
+input TxFlow;
+input DlyCrcEn;
+input [15:0] TxPauseTV;
+input [47:0] MAC;
+
+output TxCtrlStartFrm;
+output TxCtrlEndFrm;
+output SendingCtrlFrm;
+output CtrlMux;
+output [7:0] ControlData;
+output WillSendControlFrame;
+output BlockTxDone;
+
+reg SendingCtrlFrm;
+reg CtrlMux;
+reg WillSendControlFrame;
+reg [3:0] DlyCrcCnt;
+reg [5:0] ByteCnt;
+reg ControlEnd_q;
+reg [7:0] MuxedCtrlData;
+reg TxCtrlStartFrm;
+reg TxCtrlStartFrm_q;
+reg TxCtrlEndFrm;
+reg [7:0] ControlData;
+reg TxUsedDataIn_q;
+reg BlockTxDone;
+
+wire IncrementDlyCrcCnt;
+wire ResetByteCnt;
+wire IncrementByteCnt;
+wire ControlEnd;
+wire IncrementByteCntBy2;
+wire EnableCnt;
+
+
+// A command for Sending the control frame is active (latched)
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ WillSendControlFrame <= #Tp 1'b0;
+ else
+ if(TxCtrlEndFrm & CtrlMux)
+ WillSendControlFrame <= #Tp 1'b0;
+ else
+ if(TPauseRq & TxFlow)
+ WillSendControlFrame <= #Tp 1'b1;
+end
+
+
+// Generation of the transmit control packet start frame
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ TxCtrlStartFrm <= #Tp 1'b0;
+ else
+ if(TxUsedDataIn_q & CtrlMux)
+ TxCtrlStartFrm <= #Tp 1'b0;
+ else
+ if(WillSendControlFrame & ~TxUsedDataOut & (TxDoneIn | TxAbortIn | TxStartFrmIn | (~TxUsedDataOutDetected)))
+ TxCtrlStartFrm <= #Tp 1'b1;
+end
+
+
+
+// Generation of the transmit control packet end frame
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ TxCtrlEndFrm <= #Tp 1'b0;
+ else
+ if(ControlEnd | ControlEnd_q)
+ TxCtrlEndFrm <= #Tp 1'b1;
+ else
+ TxCtrlEndFrm <= #Tp 1'b0;
+end
+
+
+// Generation of the multiplexer signal (controls muxes for switching between
+// normal and control packets)
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ CtrlMux <= #Tp 1'b0;
+ else
+ if(WillSendControlFrame & ~TxUsedDataOut)
+ CtrlMux <= #Tp 1'b1;
+ else
+ if(TxDoneIn)
+ CtrlMux <= #Tp 1'b0;
+end
+
+
+
+// Generation of the Sending Control Frame signal (enables padding and CRC)
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ SendingCtrlFrm <= #Tp 1'b0;
+ else
+ if(WillSendControlFrame & TxCtrlStartFrm)
+ SendingCtrlFrm <= #Tp 1'b1;
+ else
+ if(TxDoneIn)
+ SendingCtrlFrm <= #Tp 1'b0;
+end
+
+
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ TxUsedDataIn_q <= #Tp 1'b0;
+ else
+ TxUsedDataIn_q <= #Tp TxUsedDataIn;
+end
+
+
+
+// Generation of the signal that will block sending the Done signal to the eth_wishbone module
+// While sending the control frame
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ BlockTxDone <= #Tp 1'b0;
+ else
+ if(TxCtrlStartFrm)
+ BlockTxDone <= #Tp 1'b1;
+ else
+ if(TxStartFrmIn)
+ BlockTxDone <= #Tp 1'b0;
+end
+
+
+always @ (posedge MTxClk)
+begin
+ ControlEnd_q <= #Tp ControlEnd;
+ TxCtrlStartFrm_q <= #Tp TxCtrlStartFrm;
+end
+
+
+assign IncrementDlyCrcCnt = CtrlMux & TxUsedDataIn & ~DlyCrcCnt[2];
+
+
+// Delayed CRC counter
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ DlyCrcCnt <= #Tp 4'h0;
+ else
+ if(ResetByteCnt)
+ DlyCrcCnt <= #Tp 4'h0;
+ else
+ if(IncrementDlyCrcCnt)
+ DlyCrcCnt <= #Tp DlyCrcCnt + 1'b1;
+end
+
+
+assign ResetByteCnt = TxReset | (~TxCtrlStartFrm & (TxDoneIn | TxAbortIn));
+assign IncrementByteCnt = CtrlMux & (TxCtrlStartFrm & ~TxCtrlStartFrm_q & ~TxUsedDataIn | TxUsedDataIn & ~ControlEnd);
+assign IncrementByteCntBy2 = CtrlMux & TxCtrlStartFrm & (~TxCtrlStartFrm_q) & TxUsedDataIn; // When TxUsedDataIn and CtrlMux are set at the same time
+
+assign EnableCnt = (~DlyCrcEn | DlyCrcEn & (&DlyCrcCnt[1:0]));
+// Byte counter
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ ByteCnt <= #Tp 6'h0;
+ else
+ if(ResetByteCnt)
+ ByteCnt <= #Tp 6'h0;
+ else
+ if(IncrementByteCntBy2 & EnableCnt)
+ ByteCnt <= #Tp (ByteCnt[5:0] ) + 2'h2;
+ else
+ if(IncrementByteCnt & EnableCnt)
+ ByteCnt <= #Tp (ByteCnt[5:0] ) + 1'b1;
+end
+
+
+assign ControlEnd = ByteCnt[5:0] == 6'h22;
+
+
+// Control data generation (goes to the TxEthMAC module)
+always @ (ByteCnt or DlyCrcEn or MAC or TxPauseTV or DlyCrcCnt)
+begin
+ case(ByteCnt)
+ 6'h0: if(~DlyCrcEn | DlyCrcEn & (&DlyCrcCnt[1:0]))
+ MuxedCtrlData[7:0] = 8'h01; // Reserved Multicast Address
+ else
+ MuxedCtrlData[7:0] = 8'h0;
+ 6'h2: MuxedCtrlData[7:0] = 8'h80;
+ 6'h4: MuxedCtrlData[7:0] = 8'hC2;
+ 6'h6: MuxedCtrlData[7:0] = 8'h00;
+ 6'h8: MuxedCtrlData[7:0] = 8'h00;
+ 6'hA: MuxedCtrlData[7:0] = 8'h01;
+ 6'hC: MuxedCtrlData[7:0] = MAC[47:40];
+ 6'hE: MuxedCtrlData[7:0] = MAC[39:32];
+ 6'h10: MuxedCtrlData[7:0] = MAC[31:24];
+ 6'h12: MuxedCtrlData[7:0] = MAC[23:16];
+ 6'h14: MuxedCtrlData[7:0] = MAC[15:8];
+ 6'h16: MuxedCtrlData[7:0] = MAC[7:0];
+ 6'h18: MuxedCtrlData[7:0] = 8'h88; // Type/Length
+ 6'h1A: MuxedCtrlData[7:0] = 8'h08;
+ 6'h1C: MuxedCtrlData[7:0] = 8'h00; // Opcode
+ 6'h1E: MuxedCtrlData[7:0] = 8'h01;
+ 6'h20: MuxedCtrlData[7:0] = TxPauseTV[15:8]; // Pause timer value
+ 6'h22: MuxedCtrlData[7:0] = TxPauseTV[7:0];
+ default: MuxedCtrlData[7:0] = 8'h0;
+ endcase
+end
+
+
+// Latched Control data
+always @ (posedge MTxClk or posedge TxReset)
+begin
+ if(TxReset)
+ ControlData[7:0] <= #Tp 8'h0;
+ else
+ if(~ByteCnt[0])
+ ControlData[7:0] <= #Tp MuxedCtrlData[7:0];
+end
+
+
+
+endmodule