library IEEE; use IEEE.STD_LOGIC_1164.all; use IEEE.NUMERIC_STD.all; entity CounterDown4 is port ( clk: in std_logic; count : out std_logic_vector(3 downto 0) ); end CounterDown4; architecture Behavioral of CounterDown4 is signal s_count : unsigned(3 downto 0); begin process(clk) begin if (rising_edge(clk)) then s_count <= s_count - 1; end if; end process; count <= std_logic_vector(s_count); end Behavioral;