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[/] [present/] [trunk/] [DecodeTesting/] [rtl/] [vhdl/] [counter_inv.vhd] - Rev 4
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----------------------------------------------------------------------- ---- ---- ---- Present - a lightweight block cipher project ---- ---- ---- ---- This file is part of the Present - a lightweight block ---- ---- cipher project ---- ---- http://www.http://opencores.org/project,present ---- ---- ---- ---- Description: ---- ---- Typical construction of 5bit counter. It is counting ---- ---- down. Nothing special. ---- ---- To Do: ---- ---- ---- ---- Author(s): ---- ---- - Krzysztof Gajewski, gajos@opencores.org ---- ---- k.gajewski@gmail.com ---- ---- ---- ----------------------------------------------------------------------- ---- ---- ---- Copyright (C) 2013 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 ---- ---- ---- ----------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; entity counter_inv is generic ( w_5 : integer := 5 ); port ( clk, reset, cnt_res : in std_logic; num : out std_logic_vector (w_5-1 downto 0) ); end counter_inv; architecture Behavioral of counter_inv is signal cnt : std_logic_vector(w_5-1 downto 0) := (others => '0'); begin licznik : process (clk, reset, cnt) begin if (reset = '1') then cnt <= (others => '1'); elsif (clk'Event and clk = '1') then if (cnt_res = '1') then cnt <= cnt - 1; end if; end if; end process licznik; num <= cnt; end Behavioral;