38.vhd

可以轻松实现秒表计数流水灯计数功能控制器

LIBRARY ieee;
USE ieee.std_logic_1164.all;
ENTITY decorder38 IS 
PORT(g1,g2a,g2b:in std_logic;
        a,b,c:in std_logic;
            y:out std_logic_vector(7 downto 0));
END decorder38;

ARCHITECTURE behave OF decorder38 IS
signal indata:std_logic_vector(2 downto 0);
BEGIN
  indata<=c&b&a;
  PROCESS(indata,g1,g2a,g2b)
    BEGIN
      IF(g1='1' and g2a='0' and g2b='0') THEN
        CASE indata IS 
        WHEN "000"=>y<="11111110";
        WHEN "001"=>y<="11111101";
        WHEN "010"=>y<="11111011";
        WHEN "011"=>y<="11110111";
        WHEN "100"=>y<="11101111";
        WHEN "101"=>y<="11011111";
        WHEN "110"=>y<="10111111";
        WHEN "111"=>y<="01111111";
        WHEN others=>y<="XXXXXXXX";
      END CASE;
  ELSE
        y<="11111111";
       END if;
  END PROSESS;
END behave;