Subversion Repositories common_components

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

--

-- Copyright (C) 2009

-- 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/>.

--

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

LIBRARY IEEE, common_pkg_lib;

USE IEEE.std_logic_1164.ALL;

USE common_pkg_lib.common_pkg.ALL;

ENTITY common_pipeline IS

  GENERIC (

    g_representation : STRING  := "SIGNED";   -- or "UNSIGNED"

    g_pipeline       : NATURAL := 1;  -- 0 for wires, > 0 for registers, 

    g_reset_value    : INTEGER := 0;

    g_in_dat_w       : NATURAL := 8;

    g_out_dat_w      : NATURAL := 9

  );

  PORT (

    rst     : IN  STD_LOGIC := '0';

    clk     : IN  STD_LOGIC;

    clken   : IN  STD_LOGIC := '1';

    in_clr  : IN  STD_LOGIC := '0';

    in_en   : IN  STD_LOGIC := '1';

    in_dat  : IN  STD_LOGIC_VECTOR(g_in_dat_w-1 DOWNTO 0);

    out_dat : OUT STD_LOGIC_VECTOR(g_out_dat_w-1 DOWNTO 0)

  );

END common_pipeline;

ARCHITECTURE rtl OF common_pipeline IS

  CONSTANT c_reset_value : STD_LOGIC_VECTOR(out_dat'RANGE) := TO_SVEC(g_reset_value, out_dat'LENGTH);

  TYPE t_out_dat IS ARRAY (NATURAL RANGE <>) OF STD_LOGIC_VECTOR(out_dat'RANGE);

  SIGNAL out_dat_p  : t_out_dat(0 TO g_pipeline) := (OTHERS=>c_reset_value);

BEGIN

  gen_pipe_n : IF g_pipeline>0 GENERATE

    p_clk : PROCESS(clk, rst)

    BEGIN

      IF rst='1' THEN

        out_dat_p(1 TO g_pipeline) <= (OTHERS=>c_reset_value);

      ELSIF rising_edge(clk) THEN

        IF clken='1' THEN

          IF in_clr = '1' THEN

            out_dat_p(1 TO g_pipeline) <= (OTHERS=>c_reset_value);

          ELSIF in_en = '1' THEN

            out_dat_p(1 TO g_pipeline) <= out_dat_p(0 TO g_pipeline-1);

          END IF;

        END IF;

      END IF;

    END PROCESS;

  END GENERATE;

  out_dat_p(0) <= RESIZE_SVEC(in_dat, out_dat'LENGTH) WHEN g_representation=  "SIGNED" ELSE

                  RESIZE_UVEC(in_dat, out_dat'LENGTH) WHEN g_representation="UNSIGNED";

  out_dat <= out_dat_p(g_pipeline);

END rtl;