decoder.vhd

采用VHDL语言设计了一个打铃系统。该系统已经调试

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity decoder is
    Port (seg:in std_logic_vector(3 downto 0);
	       q3:out std_logic_vector(6 downto 0)
			 );
end decoder;

architecture Behavioral of decoder is

begin
process(seg)
begin
  case seg is
    when "0000" =>
                  q3<="0000001";
                  --0
    when "0001" =>
                  q3<="1001111";
                  --1
    when "0010" =>
                  q3<="0010010";
                  --2
    when "0011" =>
                  q3<="0000110";
                  --3
    when "0100" =>
                  q3<="1001100";
                 --4
    when "0101" =>
                  q3<="0100100";
                  --5
	 when "0110" =>
	               q3<="0100000";
                 --6
    when "0111" =>
                  q3<="0001111";
                  
    when "1000" =>
                  q3<="0000000";
                  --8
    when "1001" =>
                  q3<="0000100";
                 --9
	 when others =>
	          q3<="0111000";
                  
 
  end case;
end process;

end Behavioral;