timeselect.vhd

VHDL实现的交通灯程序

library ieee;
use ieee.std_logic_1164.all;

entity TimeSelect is
	port(
		sel:in std_logic_vector(2 downto 0);
		timeh1,timeh2,timel1,timel2:in std_logic_vector(3 downto 0);
		catn:out std_logic_vector(5 downto 0);
		time_out:out std_logic_vector(3 downto 0)
		);
end TimeSelect;

architecture TimeSelect_arc of TimeSelect is
begin
	process(sel)
	begin
		case sel is
			when "000"=>time_out<=timeh1;
					   catn<="111110";
			when "001"=>time_out<=timel1;
					   catn<="111101";
			when "010"=>time_out<=timeh2;
					   catn<="101111";
			when "011"=>time_out<=timel2;
					   catn<="011111";
			when others=>time_out<="0000";
					   catn<="111111";
		end case;
	end process;
end;