library ieee;
use ieee.std_logic_1164.all;

-- Logic for x4x238 active high decoder with enable
-- a is the select, e is the enable, o is the output
-- 09.15.2002 William Dubel

entity decoder is port(
	a:	in std_logic_vector(2 downto 0);
	e:	in std_logic_vector(3 downto 1);
	o:	out std_logic_vector(0 to 7));
end decoder;

architecture archdecoder of decoder is
begin
decode:	process (a, e)
	begin
		if e = "001" then
			case a is
				when "000" => o <= "10000000";
				when "001" => o <= "01000000";
				when "010" => o <= "00100000";
				when "011" => o <= "00010000";
				when "100" => o <= "00001000";
				when "101" => o <= "00000100";
				when "110" => o <= "00000010";
				when "111" => o <= "00000001";
				when others => o <= "--------";
			end case;
		else
			o <= "ZZZZZZZZ";
		end if;
end process decode;
end archdecoder;