// Indicating start of the reception process
assign SetWriteRxDataToFifo = (RxValid & RxReady & ~RxStartFrm & RxEnableWindow & (&RxByteCnt)) | 
                              (RxValid & RxReady &  RxStartFrm & (&RxPointerLSB_rst))           | 
                              (ShiftWillEnd & LastByteIn & (&RxByteCnt));

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    WriteRxDataToFifo <=#Tp 1'b0;
  else
  if(SetWriteRxDataToFifo & ~RxAbort)
    WriteRxDataToFifo <=#Tp 1'b1;
  else
  if(WriteRxDataToFifoSync2 | RxAbort)
    WriteRxDataToFifo <=#Tp 1'b0;
end



always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    WriteRxDataToFifoSync1 <=#Tp 1'b0;
  else
  if(WriteRxDataToFifo)
    WriteRxDataToFifoSync1 <=#Tp 1'b1;
  else
    WriteRxDataToFifoSync1 <=#Tp 1'b0;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    WriteRxDataToFifoSync2 <=#Tp 1'b0;
  else
    WriteRxDataToFifoSync2 <=#Tp WriteRxDataToFifoSync1;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    WriteRxDataToFifoSync3 <=#Tp 1'b0;
  else
    WriteRxDataToFifoSync3 <=#Tp WriteRxDataToFifoSync2;
end

wire WriteRxDataToFifo_wb;
assign WriteRxDataToFifo_wb = WriteRxDataToFifoSync2 & ~WriteRxDataToFifoSync3;


reg LatchedRxStartFrm;
reg SyncRxStartFrm;
reg SyncRxStartFrm_q;
reg SyncRxStartFrm_q2;
wire RxFifoReset;

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    LatchedRxStartFrm <=#Tp 0;
  else
  if(RxStartFrm & ~SyncRxStartFrm_q)
    LatchedRxStartFrm <=#Tp 1;
  else
  if(SyncRxStartFrm_q)
    LatchedRxStartFrm <=#Tp 0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    SyncRxStartFrm <=#Tp 0;
  else
  if(LatchedRxStartFrm)
    SyncRxStartFrm <=#Tp 1;
  else
    SyncRxStartFrm <=#Tp 0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    SyncRxStartFrm_q <=#Tp 0;
  else
    SyncRxStartFrm_q <=#Tp SyncRxStartFrm;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    SyncRxStartFrm_q2 <=#Tp 0;
  else
    SyncRxStartFrm_q2 <=#Tp SyncRxStartFrm_q;
end


assign RxFifoReset = SyncRxStartFrm_q & ~SyncRxStartFrm_q2;


eth_fifo #(`ETH_RX_FIFO_DATA_WIDTH, `ETH_RX_FIFO_DEPTH, `ETH_RX_FIFO_CNT_WIDTH)
rx_fifo (.data_in(RxDataLatched2),                      .data_out(m_wb_dat_o), 
         .clk(WB_CLK_I),                                .reset(Reset), 
         .write(WriteRxDataToFifo_wb & ~RxBufferFull),  .read(MasterWbRX & m_wb_ack_i), 
         .clear(RxFifoReset),                           .full(RxBufferFull), 
         .almost_full(),                                .almost_empty(RxBufferAlmostEmpty), 
         .empty(RxBufferEmpty),                         .cnt(rxfifo_cnt)
        );

assign enough_data_in_rxfifo_for_burst = rxfifo_cnt>=`ETH_BURST_LENGTH;
assign enough_data_in_rxfifo_for_burst_plus1 = rxfifo_cnt>`ETH_BURST_LENGTH;
assign WriteRxDataToMemory = ~RxBufferEmpty;
assign rx_burst = rx_burst_en & WriteRxDataToMemory;


// Generation of the end-of-frame signal
always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    ShiftEnded_rck <=#Tp 1'b0;
  else
  if(~RxAbort & SetWriteRxDataToFifo & StartShiftWillEnd)
    ShiftEnded_rck <=#Tp 1'b1;
  else
  if(RxAbort | ShiftEndedSync_c1 & ShiftEndedSync_c2)
    ShiftEnded_rck <=#Tp 1'b0;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    ShiftEndedSync1 <=#Tp 1'b0;
  else
    ShiftEndedSync1 <=#Tp ShiftEnded_rck;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    ShiftEndedSync2 <=#Tp 1'b0;
  else
    ShiftEndedSync2 <=#Tp ShiftEndedSync1;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    ShiftEndedSync3 <=#Tp 1'b0;
  else
  if(ShiftEndedSync1 & ~ShiftEndedSync2)
    ShiftEndedSync3 <=#Tp 1'b1;
  else
  if(ShiftEnded)
    ShiftEndedSync3 <=#Tp 1'b0;
end

// Generation of the end-of-frame signal
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    ShiftEnded <=#Tp 1'b0;
  else
  if(ShiftEndedSync3 & MasterWbRX & m_wb_ack_i & RxBufferAlmostEmpty & ~ShiftEnded)
    ShiftEnded <=#Tp 1'b1;
  else
  if(RxStatusWrite)
    ShiftEnded <=#Tp 1'b0;
end

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    ShiftEndedSync_c1 <=#Tp 1'b0;
  else
    ShiftEndedSync_c1 <=#Tp ShiftEndedSync2;
end

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    ShiftEndedSync_c2 <=#Tp 1'b0;
  else
    ShiftEndedSync_c2 <=#Tp ShiftEndedSync_c1;
end

// Generation of the end-of-frame signal
always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    RxEnableWindow <=#Tp 1'b0;
  else
  if(RxStartFrm)
    RxEnableWindow <=#Tp 1'b1;
  else
  if(RxEndFrm | RxAbort)
    RxEnableWindow <=#Tp 1'b0;
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxAbortSync1 <=#Tp 1'b0;
  else
    RxAbortSync1 <=#Tp RxAbortLatched;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxAbortSync2 <=#Tp 1'b0;
  else
    RxAbortSync2 <=#Tp RxAbortSync1;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxAbortSync3 <=#Tp 1'b0;
  else
    RxAbortSync3 <=#Tp RxAbortSync2;
end

always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxAbortSync4 <=#Tp 1'b0;
  else
    RxAbortSync4 <=#Tp RxAbortSync3;
end

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    RxAbortSyncb1 <=#Tp 1'b0;
  else
    RxAbortSyncb1 <=#Tp RxAbortSync2;
end

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    RxAbortSyncb2 <=#Tp 1'b0;
  else
    RxAbortSyncb2 <=#Tp RxAbortSyncb1;
end


always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    RxAbortLatched <=#Tp 1'b0;
  else
  if(RxAbortSyncb2)
    RxAbortLatched <=#Tp 1'b0;
  else
  if(RxAbort)
    RxAbortLatched <=#Tp 1'b1;
end


always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    LatchedRxLength[15:0] <=#Tp 16'h0;
  else
  if(LoadRxStatus)
    LatchedRxLength[15:0] <=#Tp RxLength[15:0];
end


assign RxStatusIn = {ReceivedPauseFrm, AddressMiss, RxOverrun, InvalidSymbol, DribbleNibble, ReceivedPacketTooBig, ShortFrame, LatchedCrcError, RxLateCollision};

always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    RxStatusInLatched <=#Tp 'h0;
  else
  if(LoadRxStatus)
    RxStatusInLatched <=#Tp RxStatusIn;
end


// Rx overrun
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxOverrun <=#Tp 1'b0;
  else
  if(RxStatusWrite)
    RxOverrun <=#Tp 1'b0;
  else
  if(RxBufferFull & WriteRxDataToFifo_wb)
    RxOverrun <=#Tp 1'b1;
end



wire TxError;
assign TxError = TxUnderRun | RetryLimit | LateCollLatched | CarrierSenseLost;

wire RxError;

// ShortFrame (RxStatusInLatched[2]) can not set an error because short frames
// are aborted when signal r_RecSmall is set to 0 in MODER register. 
// AddressMiss is identifying that a frame was received because of the promiscous
// mode and is not an error
assign RxError = (|RxStatusInLatched[6:3]) | (|RxStatusInLatched[1:0]);



reg RxStatusWriteLatched;
reg RxStatusWriteLatched_sync1;
reg RxStatusWriteLatched_sync2;
reg RxStatusWriteLatched_syncb1;
reg RxStatusWriteLatched_syncb2;


// Latching and synchronizing RxStatusWrite signal. This signal is used for clearing the ReceivedPauseFrm signal
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxStatusWriteLatched <=#Tp 1'b0;
  else
  if(RxStatusWriteLatched_syncb2)
    RxStatusWriteLatched <=#Tp 1'b0;        
  else
  if(RxStatusWrite)
    RxStatusWriteLatched <=#Tp 1'b1;
end


always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    begin
      RxStatusWriteLatched_sync1 <=#Tp 1'b0;
      RxStatusWriteLatched_sync2 <=#Tp 1'b0;
    end
  else
    begin
      RxStatusWriteLatched_sync1 <=#Tp RxStatusWriteLatched;
      RxStatusWriteLatched_sync2 <=#Tp RxStatusWriteLatched_sync1;
    end
end


always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    begin
      RxStatusWriteLatched_syncb1 <=#Tp 1'b0;
      RxStatusWriteLatched_syncb2 <=#Tp 1'b0;
    end
  else
    begin
      RxStatusWriteLatched_syncb1 <=#Tp RxStatusWriteLatched_sync2;
      RxStatusWriteLatched_syncb2 <=#Tp RxStatusWriteLatched_syncb1;
    end
end



// Tx Done Interrupt
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxB_IRQ <=#Tp 1'b0;
  else
  if(TxStatusWrite & TxIRQEn)
    TxB_IRQ <=#Tp ~TxError;
  else
    TxB_IRQ <=#Tp 1'b0;
end


// Tx Error Interrupt
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    TxE_IRQ <=#Tp 1'b0;
  else
  if(TxStatusWrite & TxIRQEn)
    TxE_IRQ <=#Tp TxError;
  else
    TxE_IRQ <=#Tp 1'b0;
end


// Rx Done Interrupt
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxB_IRQ <=#Tp 1'b0;
  else
  if(RxStatusWrite & RxIRQEn & ReceivedPacketGood & (~ReceivedPauseFrm | ReceivedPauseFrm & r_PassAll & (~r_RxFlow)))
    RxB_IRQ <=#Tp (~RxError);
  else
    RxB_IRQ <=#Tp 1'b0;
end


// Rx Error Interrupt
always @ (posedge WB_CLK_I or posedge Reset)
begin
  if(Reset)
    RxE_IRQ <=#Tp 1'b0;
  else
  if(RxStatusWrite & RxIRQEn & (~ReceivedPauseFrm | ReceivedPauseFrm & r_PassAll & (~r_RxFlow)))
    RxE_IRQ <=#Tp RxError;
  else
    RxE_IRQ <=#Tp 1'b0;
end


// Busy Interrupt

reg Busy_IRQ_rck;
reg Busy_IRQ_sync1;
reg Busy_IRQ_sync2;
reg Busy_IRQ_sync3;
reg Busy_IRQ_syncb1;
reg Busy_IRQ_syncb2;


always @ (posedge MRxClk or posedge Reset)
begin
  if(Reset)
    Busy_IRQ_rck <=#Tp 1'b0;
  else
  if(RxValid & RxStartFrm & ~RxReady)
    Busy_IRQ_rck <=#Tp 1'b1;
  else
  if(Busy_IRQ_syncb2)
    Busy_IRQ_rck <=#Tp 1'b0;
end

always @ (posedge WB_CLK_I)
begin
    Busy_IRQ_sync1 <=#Tp Busy_IRQ_rck;
    Busy_IRQ_sync2 <=#Tp Busy_IRQ_sync1;
    Busy_IRQ_sync3 <=#Tp Busy_IRQ_sync2;
end

always @ (posedge MRxClk)
begin
    Busy_IRQ_syncb1 <=#Tp Busy_IRQ_sync2;
    Busy_IRQ_syncb2 <=#Tp Busy_IRQ_syncb1;
end

assign Busy_IRQ = Busy_IRQ_sync2 & ~Busy_IRQ_sync3;


         


endmodule