ram_dp_sr_sw.vhd

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-- Design Name : ram_dp_sr_sw
-- File Name   : ram_dp_sr_sw.vhd
-- Function    : Synchronous read write RAM
-- Coder       : Deepak Kumar Tala (Verilog)
-- Translator  : Alexander H Pham (VHDL)
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library ieee;
    use ieee.std_logic_1164.all;
    use ieee.std_logic_unsigned.all;

entity ram_dp_sr_sw is
    generic (
        DATA_WIDTH :integer := 8;
        ADDR_WIDTH :integer := 8
    );
    port (
        clk       :in    std_logic;                                 -- Clock Input
        address_0 :in    std_logic_vector (ADDR_WIDTH-1 downto 0);  -- address_0 Input
        data_0    :inout std_logic_vector (DATA_WIDTH-1 downto 0);  -- data_0 bi-directional
        cs_0      :in    std_logic;                                 -- Chip Select
        we_0      :in    std_logic;                                 -- Write Enable/Read Enable
        oe_0      :in    std_logic;                                 -- Output Enable
        address_1 :in    std_logic_vector (ADDR_WIDTH-1 downto 0);  -- address_1 Input
        data_1    :inout std_logic_vector (DATA_WIDTH-1 downto 0);  -- data_1 bi-directional
        cs_1      :in    std_logic;                                 -- Chip Select
        we_1      :in    std_logic;                                 -- Write Enable/Read Enable
        oe_1      :in    std_logic                                  -- Output Enable
    );
end entity;
architecture rtl of ram_dp_sr_sw is
    ----------------Internal variables----------------
    constant RAM_DEPTH :integer := 2**ADDR_WIDTH;

    signal data_0_out :std_logic_vector (DATA_WIDTH-1 downto 0);
    signal data_1_out :std_logic_vector (DATA_WIDTH-1 downto 0);

    type RAM is array (integer range <>)of std_logic_vector (DATA_WIDTH-1 downto 0);
    signal mem : RAM (0 to RAM_DEPTH-1);

begin
    ----------------Code Starts Here------------------
    -- Memory Write Block
    -- Write Operation : When we_0 = 1, cs_0 = 1
    MEM_WRITE:
    process (clk) begin
        if (rising_edge(clk)) then
            if ( cs_0 = '1' and we_0 = '1') then
                mem(conv_integer(address_0)) <= data_0;
            elsif (cs_1 = '1' and we_1 = '1') then
                mem(conv_integer(address_1)) <= data_1;
            end if;
        end if;
    end process;

    -- Tri-State Buffer control
    data_0 <= data_0_out when (cs_0 = '1' and oe_0 = '1' and we_0 = '0') else (others=>'Z');

    -- Memory Read Block
    MEM_READ_0:
    process (clk) begin
        if (rising_edge(clk)) then
            if (cs_0 = '1' and we_0 = '0' and oe_0 = '1') then
                data_0_out <= mem(conv_integer(address_0));
            else
                data_0_out <= (others=>'0');
            end if;
        end if;
    end process;

    --Second Port of RAM
    -- Tri-State Buffer control
    -- output : When we_0 = 0, oe_0 = 1, cs_0 = 1
    data_1 <= data_1_out when (cs_1 = '1' and oe_1 = '1' and we_1 = '0') else (others=>'Z');

    -- Memory Read Block 1
    MEM_READ_1:
    process (clk) begin
        if (rising_edge(clk)) then
            if (cs_1 = '1' and we_1 = '0' and oe_1 = '1') then
                data_1_out <= mem(conv_integer(address_1));
            else
                data_1_out <= (others=>'0');
            end if;
        end if;
    end process;

end architecture;