1 数据类型转换

2 常用库

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.numeric_bit.all;

3 关键字

4 简单的例子

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.numeric_bit.all;


entity vhdl_top is
	port(
		i_key : in	std_logic_vector(3 downto 0);
		o_led : out std_logic_vector(3 downto 0)
	);
end entity vhdl_top;

architecture bhv of vhdl_top is
	component not_gate is
		port(
			i_key : in	std_logic_vector(3 downto 0);
			o_led : out std_logic_vector(3 downto 0)
		);
	end component;
			
begin
	
	 u_not_gate : not_gate
		port map(
			i_key => i_key,
			o_led => o_led
		);

end bhv;