古博姚青华 发表于 2005-6-11 19:41:52

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

entity qiangdaa is

port(rst:in std_logic; 复位键

a1,a2,a3,a4,a5:in std_logic;五个抢答按键

cade:out std_logic_vector(3 downto 0));

end entity qiangdaa;

architecture behav of qiangdaa is

signal a:std_logic_vector(4 downto 0);

signal scade:std_logic_vector(3 downto 0);

begin

process(rst,a1,a2,a3,a4,a5)

begin

if rst='0' then a<="00000";

elsif (a1='0')and(a2='1')and(a3='1')and(a4='1')and(a5='1')and(scade=0) then

        a<=a1&a2&a3&a4&a5;

elsif (a1='1')and(a2='0')and(a3='1')and(a4='1')and(a5='1')and(scade=0) then

        a<=a1&a2&a3&a4&a5;

elsif (a1='1')and(a2='1')and(a3='0')and(a4='1')and(a5='1')and(scade=0) then

        a<=a1&a2&a3&a4&a5;

elsif (a1='1')and(a2='1')and(a3='1')and(a4='0')and(a5='1')and(scade=0) then

        a<=a1&a2&a3&a4&a5;

elsif (a1='1')and(a2='1')and(a3='1')and(a4='1')and(a5='0')and(scade=0) then

        a<=a1&a2&a3&a4&a5;

end if;

end process;

process(a)

begin

 case a is

when "01111"=>scade<="0001";参赛者号码

when "10111"=>scade<="0010";

when "11011"=>scade<="0011";

                when "11101"=>scade<="0100";

        when "11110"=>scade<="0101";

                when others=>scade<="0000";

        end case;

        cade<=scade;

end process;

end;