Subversion Repositories spdif_interface

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---- WISHBONE SPDIF IP Core                                       ----

----                                                              ----

---- This file is part of the SPDIF project                       ----

---- http://www.opencores.org/cores/spdif_interface/              ----

----                                                              ----

---- Description                                                  ----

---- Generic control register.                                    ----

----                                                              ----

----                                                              ----

---- To Do:                                                       ----

---- -                                                            ----

----                                                              ----

---- Author(s):                                                   ----

---- - Geir Drange, gedra@opencores.org                           ----

----                                                              ----

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---- Copyright (C) 2004 Authors and OPENCORES.ORG                 ----

----                                                              ----

---- This source file may be used and distributed without         ----

---- restriction provided that this copyright statement is not    ----

---- removed from the file and that any derivative work contains  ----

---- the original copyright notice and the associated disclaimer. ----

----                                                              ----

---- This source file is free software; you can redistribute it   ----

---- and/or modify it under the terms of the GNU Lesser General   ----

---- Public License as published by the Free Software Foundation; ----

---- either version 2.1 of the License, or (at your option) any   ----

---- later version.                                               ----

----                                                              ----

---- This source 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 Lesser General Public License for more  ----

---- details.                                                     ----

----                                                              ----

---- You should have received a copy of the GNU Lesser General    ----

---- Public License along with this source; if not, download it   ----

---- from http://www.opencores.org/lgpl.shtml                     ----

----                                                              ----

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--

-- CVS Revision History

--

-- $Log: not supported by cvs2svn $

-- Revision 1.1  2004/06/03 17:47:17  gedra

-- Generic control register. Used in both recevier and transmitter.

--

--

library IEEE;

use IEEE.std_logic_1164.all;

use IEEE.std_logic_arith.all;

entity gen_control_reg is

  generic (DATA_WIDTH: integer;

           ACTIVE_BIT_MASK: std_logic_vector); -- note that this vector is (0 to xx),

  port (                                       -- reverse order

    clk: in std_logic;   -- clock  

    rst: in std_logic; -- reset

    ctrl_wr: in std_logic; -- control register write    

    ctrl_rd: in std_logic; -- control register read

    ctrl_din: in std_logic_vector(DATA_WIDTH - 1 downto 0); -- write data

    ctrl_dout: out std_logic_vector(DATA_WIDTH - 1 downto 0); -- read data

    ctrl_bits: out std_logic_vector(DATA_WIDTH - 1 downto 0)); -- control bits

end gen_control_reg;

architecture rtl of gen_control_reg is

  signal ctrl_internal: std_logic_vector(DATA_WIDTH - 1 downto 0);

begin

  ctrl_dout <= ctrl_internal when ctrl_rd = '1' else (others => '0');

  ctrl_bits <= ctrl_internal;

-- control register generation

  CTRLREG: for k in ctrl_din'range generate

    -- active bits can be written to

    ACTIVE: if  ACTIVE_BIT_MASK(k) = '1' generate

      CBIT: process (clk, rst)

      begin

        if rst = '1' then

          ctrl_internal(k) <= '0';

        else

          if rising_edge(clk) then

            if ctrl_wr = '1' then

              ctrl_internal(k) <= ctrl_din(k);

            end if;

          end if;

        end if;

      end process CBIT;

    end generate ACTIVE;

    -- inactive bits are always 0

    INACTIVE: if ACTIVE_BIT_MASK(k) = '0' generate

      ctrl_internal(k) <= '0';

    end generate INACTIVE;

  end generate CTRLREG;

end rtl;