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MROD_X_Out

StatusCounter

Documentation for architecture MROD_X_Out/StatusCounter/a1

VHDL Contents

    1  -- EASE/HDL begin --------------------------------------------------------------
    2  -- Architecture 'a1' of 'StatusCounter.
    3  --------------------------------------------------------------------------------
    4  -- Copy of the interface declaration of Entity 'StatusCounter' :
    5  -- 
    6  --   generic(
    7  --     NumWords  :  positive := 256 ;
    8  --     NumWordsU :  positive := 8 );
    9  --   port(
   10  --     Clk   : in     std_logic;
   11  --     Empty : out    std_logic;
   12  --     Full  : out    std_logic;
   13  --     RReq  : in     std_logic;
   14  --     Rst_n : in     std_logic;
   15  --     UsedW : out    std_logic_vector(NumWordsU downto 0);
   16  --     WReq  : in     std_logic);
   17  -- 
   18  -- EASE/HDL end ----------------------------------------------------------------
   19  
   20  architecture a1 of StatusCounter is
   21  BEGIN
   22     Process (Clk, Rst_n)
   23        --Note! Count width is NumWordsU and NOT NumWordsU-1 !!
   24        --Fifo state can be filled up 2^NumWords plus empty!
   25        Variable Count: Unsigned(NumWordsU Downto 0);
   26     Begin
   27        If Rst_n = '0' Then
   28           Count := (Others => '0');
   29           Empty <= '1';
   30           Full <= '0';
   31        ElsIf Rising_Edge(Clk) Then
   32  
   33           If WReq = '1' Then
   34              Count := Count + 2;
   35           End If;
   36  
   37           If RReq = '1' Then
   38              Count := Count - 1;
   39           End If;
   40  
   41           If To_Integer(Count) + 2 > NumWords Then
   42              Full <= '1';
   43           Else
   44              --To_Integer(Count) + 2 <= NumWords
   45              Full <= '0';        
   46           End If;
   47  
   48           If To_Integer(Count) = 0 Then
   49              Empty <= '1';
   50           Else
   51              Empty <= '0';
   52           End If;
   53        End If;
   54        UsedW <= Std_Logic_Vector(Count);
   55     End Process;
   56  end architecture a1 ; -- of StatusCounter
   57