rx_burst_en<=#Tp MasterWbRX ? enough_data_in_rxfifo_for_burst_plus1 : enough_data_in_rxfifo_for_burst;  // Counter is not decremented, yet, so plus1 is used.
            `ifdef ETH_WISHBONE_B3
              m_wb_cti_o <=#Tp 3'b0;
            `endif
          end
        8'b00_00_00_00:             // whatever and no master read or write is needed (ack or err comes finishing previous access)
          begin
            tx_burst_cnt<=#Tp 0;
            tx_burst_en<=#Tp txfifo_cnt<(`ETH_TX_FIFO_DEPTH-`ETH_BURST_LENGTH) & (TxLength>(`ETH_BURST_LENGTH*4+4));
          end
        default:                    // Don't touch
          begin
            MasterWbTX <=#Tp MasterWbTX;
            MasterWbRX <=#Tp MasterWbRX;
            m_wb_cyc_o <=#Tp m_wb_cyc_o;
            m_wb_stb_o <=#Tp m_wb_stb_o;
            m_wb_sel_o <=#Tp m_wb_sel_o;
            IncrTxPointer<=#Tp IncrTxPointer;
          end
      endcase
    end
end


wire TxFifoClear;

assign TxFifoClear = (TxAbortPacket | TxRetryPacket);

eth_fifo #(`ETH_TX_FIFO_DATA_WIDTH, `ETH_TX_FIFO_DEPTH, `ETH_TX_FIFO_CNT_WIDTH)
tx_fifo ( .data_in(m_wb_dat_i),                             .data_out(TxData_wb), 
          .clk(WB_CLK_I),                                   .reset(Reset), 
          .write(MasterWbTX & m_wb_ack_i),                  .read(ReadTxDataFromFifo_wb & ~TxBufferEmpty),
          .clear(TxFifoClear),                              .full(TxBufferFull), 
          .almost_full(TxBufferAlmostFull),                 .almost_empty(TxBufferAlmostEmpty), 
          .empty(TxBufferEmpty),                            .cnt(txfifo_cnt)
        );


reg StartOccured;
reg TxStartFrm_sync1;
reg TxStartFrm_sync2;
reg TxStartFrm_syncb1;
reg TxStartFrm_syncb2;



// Start: Generation of the TxStartFrm_wb which is then synchronized to the MTxClk
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxStartFrm_wb <=#Tp 1'b0;
  else
  if(TxBDReady & ~StartOccured & (TxBufferFull | TxLengthEq0))
    TxStartFrm_wb <=#Tp 1'b1;
  else
  if(TxStartFrm_syncb2)
    TxStartFrm_wb <=#Tp 1'b0;
end

// StartOccured: TxStartFrm_wb occurs only ones at the beginning. Then it's blocked.
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    StartOccured <=#Tp 1'b0;
  else
  if(TxStartFrm_wb)
    StartOccured <=#Tp 1'b1;
  else
  if(ResetTxBDReady)
    StartOccured <=#Tp 1'b0;
end

// Synchronizing TxStartFrm_wb to MTxClk
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxStartFrm_sync1 <=#Tp 1'b0;
  else
    TxStartFrm_sync1 <=#Tp TxStartFrm_wb;
end

always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxStartFrm_sync2 <=#Tp 1'b0;
  else
    TxStartFrm_sync2 <=#Tp TxStartFrm_sync1;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxStartFrm_syncb1 <=#Tp 1'b0;
  else
    TxStartFrm_syncb1 <=#Tp TxStartFrm_sync2;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxStartFrm_syncb2 <=#Tp 1'b0;
  else
    TxStartFrm_syncb2 <=#Tp TxStartFrm_syncb1;
end

always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxStartFrm <=#Tp 1'b0;
  else
  if(TxStartFrm_sync2)
    TxStartFrm <=#Tp 1'b1;
  else
  if(TxUsedData_q | ~TxStartFrm_sync2 & (TxRetry & (~TxRetry_q) | TxAbort & (~TxAbort_q)))
    TxStartFrm <=#Tp 1'b0;
end
// End: Generation of the TxStartFrm_wb which is then synchronized to the MTxClk


// TxEndFrm_wb: indicator of the end of frame
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxEndFrm_wb <=#Tp 1'b0;
  else
  if(TxLengthEq0 & TxBufferAlmostEmpty & TxUsedData)
    TxEndFrm_wb <=#Tp 1'b1;
  else
  if(TxRetryPulse | TxDonePulse | TxAbortPulse)
    TxEndFrm_wb <=#Tp 1'b0;
end


// Marks which bytes are valid within the word.
assign TxValidBytes = TxLengthLt4 ? TxLength[1:0] : 2'b0;

reg LatchValidBytes;
reg LatchValidBytes_q;

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    LatchValidBytes <=#Tp 1'b0;
  else
  if(TxLengthLt4 & TxBDReady)
    LatchValidBytes <=#Tp 1'b1;
  else
    LatchValidBytes <=#Tp 1'b0;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    LatchValidBytes_q <=#Tp 1'b0;
  else
    LatchValidBytes_q <=#Tp LatchValidBytes;
end


// Latching valid bytes
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxValidBytesLatched <=#Tp 2'h0;
  else
  if(LatchValidBytes & ~LatchValidBytes_q)
    TxValidBytesLatched <=#Tp TxValidBytes;
  else
  if(TxRetryPulse | TxDonePulse | TxAbortPulse)
    TxValidBytesLatched <=#Tp 2'h0;
end


assign TxIRQEn          = TxStatus[14];
assign WrapTxStatusBit  = TxStatus[13];
assign PerPacketPad     = TxStatus[12];
assign PerPacketCrcEn   = TxStatus[11];


assign RxIRQEn         = RxStatus[14];
assign WrapRxStatusBit = RxStatus[13];


// Temporary Tx and Rx buffer descriptor address 
assign TempTxBDAddress[7:0] = {8{ TxStatusWrite     & ~WrapTxStatusBit}} & (TxBDAddress + 2'h2) ; // Tx BD increment or wrap (last BD)
assign TempRxBDAddress[7:0] = {8{ WrapRxStatusBit}} & (r_TxBDNum<<1)     | // Using first Rx BD
                              {8{~WrapRxStatusBit}} & (RxBDAddress + 2'h2) ; // Using next Rx BD (incremenrement address)


// Latching Tx buffer descriptor address
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxBDAddress <=#Tp 8'h0;
  else
  if(TxStatusWrite)
    TxBDAddress <=#Tp TempTxBDAddress;
end


// Latching Rx buffer descriptor address
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxBDAddress <=#Tp `ETH_TX_BD_NUM_DEF<<1;
  else
  if(TX_BD_NUM_Wr)                        // When r_TxBDNum is updated, RxBDAddress is also
    RxBDAddress <=#Tp WB_DAT_I[7:0]<<1;
  else
  if(RxStatusWrite)
    RxBDAddress <=#Tp TempRxBDAddress;
end

wire [8:0] TxStatusInLatched = {TxUnderRun, RetryCntLatched[3:0], RetryLimit, LateCollLatched, DeferLatched, CarrierSenseLost};

assign RxBDDataIn = {LatchedRxLength, 1'b0, RxStatus, 4'h0, RxStatusInLatched};
assign TxBDDataIn = {LatchedTxLength, 1'b0, TxStatus, 2'h0, TxStatusInLatched};


// Signals used for various purposes
assign TxRetryPulse   = TxRetry_wb   & ~TxRetry_wb_q;
assign TxDonePulse    = TxDone_wb    & ~TxDone_wb_q;
assign TxAbortPulse   = TxAbort_wb   & ~TxAbort_wb_q;



// Generating delayed signals
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    begin
      TxAbort_q      <=#Tp 1'b0;
      TxRetry_q      <=#Tp 1'b0;
      TxUsedData_q   <=#Tp 1'b0;
    end
  else
    begin
      TxAbort_q      <=#Tp TxAbort;
      TxRetry_q      <=#Tp TxRetry;
      TxUsedData_q   <=#Tp TxUsedData;
    end
end

// Generating delayed signals
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    begin
      TxDone_wb_q   <=#Tp 1'b0;
      TxAbort_wb_q  <=#Tp 1'b0;
      TxRetry_wb_q  <=#Tp 1'b0;
    end
  else
    begin
      TxDone_wb_q   <=#Tp TxDone_wb;
      TxAbort_wb_q  <=#Tp TxAbort_wb;
      TxRetry_wb_q  <=#Tp TxRetry_wb;
    end
end


reg TxAbortPacketBlocked;
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxAbortPacket <=#Tp 1'b0;
  else
  if(TxAbort_wb & (~tx_burst_en) & MasterWbTX & MasterAccessFinished & (~TxAbortPacketBlocked) |
     TxAbort_wb & (~MasterWbTX) & (~TxAbortPacketBlocked))
    TxAbortPacket <=#Tp 1'b1;
  else
    TxAbortPacket <=#Tp 1'b0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxAbortPacket_NotCleared <=#Tp 1'b0;
  else
  if(TxEn & TxEn_q & TxAbortPacket_NotCleared)
    TxAbortPacket_NotCleared <=#Tp 1'b0;
  else
  if(TxAbort_wb & (~tx_burst_en) & MasterWbTX & MasterAccessFinished & (~TxAbortPacketBlocked) |
     TxAbort_wb & (~MasterWbTX) & (~TxAbortPacketBlocked))
    TxAbortPacket_NotCleared <=#Tp 1'b1;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxAbortPacketBlocked <=#Tp 1'b0;
  else
  if(!TxAbort_wb & TxAbort_wb_q)
    TxAbortPacketBlocked <=#Tp 1'b0;
  else
  if(TxAbortPacket)
    TxAbortPacketBlocked <=#Tp 1'b1;
end


reg TxRetryPacketBlocked;
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxRetryPacket <=#Tp 1'b0;
  else
  if(TxRetry_wb & !tx_burst_en & MasterWbTX & MasterAccessFinished & !TxRetryPacketBlocked | 
     TxRetry_wb & !MasterWbTX & !TxRetryPacketBlocked)
    TxRetryPacket <=#Tp 1'b1;
  else
    TxRetryPacket <=#Tp 1'b0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxRetryPacket_NotCleared <=#Tp 1'b0;
  else
  if(StartTxBDRead)
    TxRetryPacket_NotCleared <=#Tp 1'b0;
  else
  if(TxRetry_wb & !tx_burst_en & MasterWbTX & MasterAccessFinished & !TxRetryPacketBlocked | 
     TxRetry_wb & !MasterWbTX & !TxRetryPacketBlocked)
    TxRetryPacket_NotCleared <=#Tp 1'b1;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxRetryPacketBlocked <=#Tp 1'b0;
  else
  if(!TxRetry_wb & TxRetry_wb_q)
    TxRetryPacketBlocked <=#Tp 1'b0;
  else
  if(TxRetryPacket)
    TxRetryPacketBlocked <=#Tp 1'b1;
end


reg TxDonePacketBlocked;
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxDonePacket <=#Tp 1'b0;
  else
  if(TxDone_wb & !tx_burst_en & MasterWbTX & MasterAccessFinished & !TxDonePacketBlocked | 
     TxDone_wb & !MasterWbTX & !TxDonePacketBlocked)
    TxDonePacket <=#Tp 1'b1;
  else
    TxDonePacket <=#Tp 1'b0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxDonePacket_NotCleared <=#Tp 1'b0;
  else
  if(TxEn & TxEn_q & TxDonePacket_NotCleared)
    TxDonePacket_NotCleared <=#Tp 1'b0;
  else
  if(TxDone_wb & !tx_burst_en & MasterWbTX & MasterAccessFinished & (~TxDonePacketBlocked) | 
     TxDone_wb & !MasterWbTX & (~TxDonePacketBlocked))
    TxDonePacket_NotCleared <=#Tp 1'b1;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxDonePacketBlocked <=#Tp 1'b0;
  else
  if(!TxDone_wb & TxDone_wb_q)
    TxDonePacketBlocked <=#Tp 1'b0;
  else
  if(TxDonePacket)
    TxDonePacketBlocked <=#Tp 1'b1;
end


// Indication of the last word
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    LastWord <=#Tp 1'b0;
  else
  if((TxEndFrm | TxAbort | TxRetry) & Flop)
    LastWord <=#Tp 1'b0;
  else
  if(TxUsedData & Flop & TxByteCnt == 2'h3)
    LastWord <=#Tp TxEndFrm_wb;
end


// Tx end frame generation
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxEndFrm <=#Tp 1'b0;
  else
  if(Flop & TxEndFrm | TxAbort | TxRetry_q)
    TxEndFrm <=#Tp 1'b0;        
  else
  if(Flop & LastWord)
    begin
      case (TxValidBytesLatched)  // synopsys parallel_case
        1 : TxEndFrm <=#Tp TxByteCnt == 2'h0;
        2 : TxEndFrm <=#Tp TxByteCnt == 2'h1;
        3 : TxEndFrm <=#Tp TxByteCnt == 2'h2;
        0 : TxEndFrm <=#Tp TxByteCnt == 2'h3;
        default : TxEndFrm <=#Tp 1'b0;
      endcase
    end
end


// Tx data selection (latching)
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxData <=#Tp 0;
  else
  if(TxStartFrm_sync2 & ~TxStartFrm)
    case(TxPointerLSB)  // synopsys parallel_case
      2'h0 : TxData <=#Tp TxData_wb[31:24];                  // Big Endian Byte Ordering
      2'h1 : TxData <=#Tp TxData_wb[23:16];                  // Big Endian Byte Ordering
      2'h2 : TxData <=#Tp TxData_wb[15:08];                  // Big Endian Byte Ordering
      2'h3 : TxData <=#Tp TxData_wb[07:00];                  // Big Endian Byte Ordering
    endcase
  else
  if(TxStartFrm & TxUsedData & TxPointerLSB==2'h3)
    TxData <=#Tp TxData_wb[31:24];                           // Big Endian Byte Ordering
  else
  if(TxUsedData & Flop)
    begin
      case(TxByteCnt)  // synopsys parallel_case
        0 : TxData <=#Tp TxDataLatched[31:24];               // Big Endian Byte Ordering
        1 : TxData <=#Tp TxDataLatched[23:16];
        2 : TxData <=#Tp TxDataLatched[15:8];
        3 : TxData <=#Tp TxDataLatched[7:0];
      endcase
    end
end


// Latching tx data
always @ (posedge MTxClk or posedge Reset)
begin
  if(Reset)
    TxDataLatched[31:0] <=#Tp 32'h0;
  else
 if(TxStartFrm_sync2 & ~TxStartFrm | TxUsedData & Flop & TxByteCnt == 2'h3 | TxStartFrm & TxUsedData & Flop & TxByteCnt == 2'h0)
    TxDataLatched[31:0] <=#Tp TxData_wb[31:0];
end


// Tx under run
always @ (posedge WB_CLK_I or posedge Reset)