Subversion Repositories astron_ram

-------------------------------------------------------------------------------

--

-- Copyright (C) 2011

-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>

-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands

--

-- This program is free software: you can redistribute it and/or modify

-- it under the terms of the GNU General Public License as published by

-- the Free Software Foundation, either version 3 of the License, or

-- (at your option) any later version.

--

-- This program is distributed in the hope that it will be useful,

-- but WITHOUT ANY WARRANTY; without even the implied warranty of

-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

-- GNU General Public License for more details.

--

-- You should have received a copy of the GNU General Public License

-- along with this program.  If not, see <http://www.gnu.org/licenses/>.

--

-------------------------------------------------------------------------------

-- Purpose: Multi page memory

-- Description:

--   When next_page_* pulses then the next access will occur in the next page.

-- Remarks:

-- . See common_paged_ram_crw_crw for details.

LIBRARY IEEE, technology_lib;

USE IEEE.std_logic_1164.ALL;

USE IEEE.numeric_std.ALL;

LIBRARY common_pkg_lib;

USE common_pkg_lib.common_pkg.ALL;

USE technology_lib.technology_select_pkg.ALL;

ENTITY common_paged_ram_r_w IS

  GENERIC (

    g_technology      : NATURAL := c_tech_select_default;

    g_str             : STRING := "use_adr";

    g_data_w          : NATURAL;

    g_nof_pages       : NATURAL := 2;  -- >= 2

    g_page_sz         : NATURAL;

    g_wr_start_page   : NATURAL := 0;

    g_rd_start_page   : NATURAL := 0;

    g_rd_latency      : NATURAL := 1

  );

  PORT (

    rst          : IN  STD_LOGIC;

    clk          : IN  STD_LOGIC;

    clken        : IN  STD_LOGIC := '1';

    wr_next_page : IN  STD_LOGIC;

    wr_adr       : IN  STD_LOGIC_VECTOR(ceil_log2(g_page_sz)-1 DOWNTO 0) := (OTHERS=>'0');

    wr_en        : IN  STD_LOGIC := '0';

    wr_dat       : IN  STD_LOGIC_VECTOR(g_data_w-1 DOWNTO 0) := (OTHERS=>'0');

    rd_next_page : IN  STD_LOGIC;

    rd_adr       : IN  STD_LOGIC_VECTOR(ceil_log2(g_page_sz)-1 DOWNTO 0) := (OTHERS=>'0');

    rd_en        : IN  STD_LOGIC := '1';

    rd_dat       : OUT STD_LOGIC_VECTOR(g_data_w-1 DOWNTO 0);

    rd_val       : OUT STD_LOGIC

  );

END common_paged_ram_r_w;

ARCHITECTURE str OF common_paged_ram_r_w IS

BEGIN

  u_rw_rw : ENTITY work.common_paged_ram_rw_rw

  GENERIC MAP (

    g_technology     => g_technology,

    g_str            => g_str,

    g_data_w         => g_data_w,

    g_nof_pages      => g_nof_pages,

    g_page_sz        => g_page_sz,

    g_start_page_a   => g_wr_start_page,

    g_start_page_b   => g_rd_start_page,

    g_rd_latency     => g_rd_latency,

    g_true_dual_port => FALSE

  )

  PORT MAP (

    rst         => rst,

    clk         => clk,

    clken       => clken,

    next_page_a => wr_next_page,

    adr_a       => wr_adr,

    wr_en_a     => wr_en,

    wr_dat_a    => wr_dat,

    rd_en_a     => '0',

    rd_dat_a    => OPEN,

    rd_val_a    => OPEN,

    next_page_b => rd_next_page,

    adr_b       => rd_adr,

    wr_en_b     => '0',

    wr_dat_b    => (OTHERS=>'0'),

    rd_en_b     => rd_en,

    rd_dat_b    => rd_dat,

    rd_val_b    => rd_val

  );

END str;