decoder.vhd

这个是数字电子时钟

library ieee;
use IEEE.STD_LOGIC_1164.ALL;
      use IEEE.STD_LOGIC_ARITH.ALL;
      use IEEE.STD_LOGIC_UNSIGNED.ALL;
      entity decoder is
      Port (din:in std_logic_vector(3 downto 0 ); --四位二进制码输入
      dout:out std_logic_vector(6 downto 0) ); --输出LED七段码
      end decoder;
      architecture Behavioral of decoder is
      begin
      process(din)
      begin
      case din is
      when "0000" => dout<="0000001";--0
      when "0001" => dout<="1001111";--1
      when "0010" => dout<="0010010";--2
      when "0011" => dout<="0000110";--3
      when "0100" => dout<="1001100";--4
      when "0101" => dout<="0100100";--5
      when "0110" => dout<="0100000";--6
      when "0111" => dout<="0001111";--7
      when "1000" => dout<="0000000";--8
      when "1001" => dout<="0000100";--9
      when others => dout<="1111111";
      end case;
      end process;
      end Behavioral;