led_pili_f_s.vhd

16bit霹靂燈 LED左右來回跑 時快時慢 也可以設定成跑馬燈形式

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

entity LED_PILI_F_S is
    Port ( CLK : in  STD_LOGIC;
           RESET : in  STD_LOGIC;
           LED : out  STD_LOGIC_VECTOR (15 downto 0));
end LED_PILI_F_S;

architecture Behavioral of LED_PILI_F_S is
signal DIVIDER : STD_LOGIC_VECTOR (29 downto 1);

signal SL_DIV : STD_LOGIC;
signal FL_DIV : STD_LOGIC;
signal DE_DIV : STD_LOGIC;
signal SHIFT_DIV : STD_LOGIC;
signal DIR : STD_LOGIC;
begin
  process(CLK,RESET)
    begin
     if RESET='0' then
        DIVIDER <= (others => '0');
     elsif CLK'event and CLK='1' then
        DIVIDER <= DIVIDER + 1; 
     end if;
  end process;  
  SL_DIV <= DIVIDER(25);
  FL_DIV <= DIVIDER(23);
  DE_DIV <= DIVIDER(29);
  SHIFT_DIV <= FL_DIV when DE_DIV = '1' else SL_DIV;
  process(SHIFT_DIV,RESET)
    variable COUNT : STD_LOGIC_VECTOR (15 downto 0);  
    begin
      if RESET='0' then
         COUNT := x"C000";
         DIR <= '0';
      elsif SHIFT_DIV'event and SHIFT_DIV='1' then 
         if DIR = '0' then 
            COUNT := COUNT(0) & COUNT(15 downto 1);
         else
            COUNT := COUNT(14 downto 0) & COUNT(15);
         end if;
         if COUNT = x"0003" then 
            DIR <= '1';
         elsif COUNT = x"C000" then
            DIR <= '0';
         end if;
      end if;
      LED <= COUNT;
  end process;
end Behavioral;