select_food2.vhd

来自「这是一个自动售货机的vhdl源码」· VHDL 代码 · 共 34 行

library ieee;
use ieee.std_logic_1164.all;
entity select_food2 is
  port(s_dog,s_ham,s_dham: in std_logic;
       reset:in std_logic;
       led_dog,led_ham,led_dham:out std_logic);
end select_food2;
ARCHITECTURE choice of select_food2 is
  signal sel:std_logic_vector(2 downto 0);
begin
   sel<=s_dog&s_ham&s_dham;
  process(sel)
    type data_out is array (0 to 2)of std_logic;
    variable output:data_out;
    begin 
     if reset='1' then 
        output:=('0','0','0');
     else
        case sel is
          when"100"=>output:=('1','0','0');   
          when"010"=>output:=('0','1','0'); 
          when"001"=>output:=('0','0','1');
          when others=>output:=('0','0','0');
        end case;
     --else  output:=('0','0','0'); 
     end if; 
      led_dog<=output(0);
      led_ham<=output(1);
      led_dham<=output(2);
 end process;
end choice;