mux4to1.vhd

CPLDFPGA嵌入式应用开发技术白金手册所配套源代码

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity mux4to1 is
	port(a,b,c,d:in std_logic;
			sel:in std_logic_vector(1 downto 0);
			q:out std_logic);
end mux4to1;
architecture rtl of mux4to1 is
begin
PROCESS(sel, a, b, c, d)
BEGIN
	CASE sel IS
		WHEN "00" =>
			q <= a;
		WHEN "01" =>
			q <= b;
		WHEN "10" =>
			q <= c;
		WHEN OTHERS =>
			q <= d;
	END CASE;
END PROCESS;
end rtl;