ledflash.vhd

eda 开发数字钟的设计具体编程代码和开发流程与设计图

--*************************************************************************************--
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity ledflash is
  port(clkin:in std_logic;  --2HZ   
       LED  :out std_logic_vector(12 downto 1)  
       );
end entity;

architecture arc of ledflash is
begin
 process(clkin) 
  variable count:integer range 0 to 31;
  begin
    if (clkin'event and clkin='1') then
    	case count is
    		when 0  => LED(12 downto 1) <= "111111111111";  count := count + 1;
    		when 1  => LED(12 downto 1) <= "111111111110";  count := count + 1;
    		when 2  => LED(12 downto 1) <= "111111111100";  count := count + 1;
    		when 3  => LED(12 downto 1) <= "111111111000";  count := count + 1;
    		when 4  => LED(12 downto 1) <= "111111110000";  count := count + 1;
    		when 5  => LED(12 downto 1) <= "111111100000";  count := count + 1;
    		when 6  => LED(12 downto 1) <= "111111000000";  count := count + 1;
    		when 7  => LED(12 downto 1) <= "111110000000";  count := count + 1;
    		when 8  => LED(12 downto 1) <= "111100000000";  count := count + 1;
    		when 9  => LED(12 downto 1) <= "111000000000";  count := count + 1;
    		when 10 => LED(12 downto 1) <= "110000000000";  count := count + 1;
    		when 11 => LED(12 downto 1) <= "100000000000";  count := count + 1;
    		when 12 => LED(12 downto 1) <= "000000000000";  count := count + 1;
    		when 13 => LED(12 downto 1) <= "111111111111";  count := count + 1;
    		when 14 => LED(12 downto 1) <= "000000000000";  count := count + 1;
    		when 15 => LED(12 downto 1) <= "111111111111";  count := count + 1;
    		when 16 => LED(12 downto 1) <= "000000000000";  count := count + 1;
    		when 17 => LED(12 downto 1) <= "100000000000";  count := count + 1;
    		when 18 => LED(12 downto 1) <= "110000000000";  count := count + 1;
    		when 19 => LED(12 downto 1) <= "111000000000";  count := count + 1;
    		when 20 => LED(12 downto 1) <= "111100000000";  count := count + 1;
    		when 21 => LED(12 downto 1) <= "111110000000";  count := count + 1;
    		when 22 => LED(12 downto 1) <= "111111000000";  count := count + 1;
    		when 23 => LED(12 downto 1) <= "111111100000";  count := count + 1;
    		when 24 => LED(12 downto 1) <= "111111110000";  count := count + 1;
    		when 25 => LED(12 downto 1) <= "111111111000";  count := count + 1;
    		when 26 => LED(12 downto 1) <= "111111111100";  count := count + 1;
    		when 27 => LED(12 downto 1) <= "111111111110";  count := count + 1;
			when 28 => LED(12 downto 1) <= "111111111111";  count := count + 1;
    		when 29 => LED(12 downto 1) <= "000000000000";  count := count + 1;
    		when 30 => LED(12 downto 1) <= "111111111111";  count := count + 1;
    		when 31 => LED(12 downto 1) <= "000000000000";  count := 0;
    		when others => count := 0;
    	end case;
    end if;
  end process;
end arc;