Subversion Repositories versatile_fft

-- A parameterized, inferable, true dual-port, common-clock block RAM in VHDL.

-- Original file was taken from: http://danstrother.com/2010/09/11/inferring-rams-in-fpgas/

-- No license information were provided by the original author.

-- Minimal modifications were introduced by me to make it suitable for my FFT core.

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

entity dp_ram_rbw_scl is

  generic (

    DATA_WIDTH : integer := 72;

    ADDR_WIDTH : integer := 10

    );

  port (

-- common clock

    clk    : in  std_logic;

    -- Port A

    we_a   : in  std_logic;

    addr_a : in  std_logic_vector(ADDR_WIDTH-1 downto 0);

    data_a : in  std_logic_vector(DATA_WIDTH-1 downto 0);

    q_a    : out std_logic_vector(DATA_WIDTH-1 downto 0);

    -- Port B

    we_b   : in  std_logic;

    addr_b : in  std_logic_vector(ADDR_WIDTH-1 downto 0);

    data_b : in  std_logic_vector(DATA_WIDTH-1 downto 0);

    q_b    : out std_logic_vector(DATA_WIDTH-1 downto 0)

    );

end dp_ram_rbw_scl;

architecture rtl of dp_ram_rbw_scl is

  -- Shared memory

  type mem_type is array ((2**ADDR_WIDTH)-1 downto 0) of std_logic_vector(DATA_WIDTH-1 downto 0);

  shared variable mem : mem_type;

begin

-- Port A

  process(clk)

  begin

    if(clk'event and clk = '1') then

      q_a <= mem(conv_integer(addr_a));

      if(we_a = '1') then

        mem(conv_integer(addr_a)) := data_a;

      end if;

    end if;

  end process;

-- Port B

  process(clk)

  begin

    if(clk'event and clk = '1') then

      q_b <= mem(conv_integer(addr_b));

      if(we_b = '1') then

        mem(conv_integer(addr_b)) := data_b;

      end if;

    end if;

  end process;

end rtl;