segment_scan_clock_24.vhd

設計VHDL24小時的時鐘

 --*******************************************
--*     CLOCK (24 Hour) And Display In      * 
--*    Scanning Seven Segment LED (6DIG)    *
--*   Filename : SEGMENT_SCAN_CLOCK_24.VHD  *
--*******************************************

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use work.CLOCK_PACK.all;
 
entity SEGMENT_SCAN_CLOCK_24 is
    Port ( CLK     : in std_logic;
           RESET   : in std_logic;
           ENABLE  : out std_logic_vector(6 downto 1);
		 SEGMENT : out std_logic_vector(7 downto 0));
end SEGMENT_SCAN_CLOCK_24;

architecture Behavioral of SEGMENT_SCAN_CLOCK_24 is
  signal SCAN_CLK    : std_logic; 
  signal CLOCK       : std_logic;
  signal CARRY_SEC   : std_logic;
  signal CARRY_MIN   : std_logic;
  signal TIME_BCD    : std_logic_vector(23 downto 0);
  signal DECODER_BCD : std_logic_vector(3 downto 0);
  signal POSITION    : std_logic_vector(6 downto 1);
begin

--********************************************
--* Decide Seven Segment's Display Location  *
--********************************************
 
  process (SCAN_CLK,RESET)

    begin
      if RESET     = '0' then 
         POSITION <= "111110";
      elsif SCAN_CLK'event and SCAN_CLK = '1' then
         POSITION <= POSITION(5 downto 1) & POSITION (6);
      end if;
  end process;
  ENABLE <= POSITION;

--*****************************************
--*  Decide Seven Segment's Display Data  *
--*****************************************

process (POSITION,TIME_BCD)

  begin 
   case POSITION is
     when "111110" => DECODER_BCD <=  TIME_BCD(3 downto 0); 
     when "111101" => DECODER_BCD <=  TIME_BCD(7 downto 4);
     when "111011" => DECODER_BCD <=  TIME_BCD(11 downto 8);
     when "110111" => DECODER_BCD <=  TIME_BCD(15 downto 12);
     when "101111" => DECODER_BCD <=  TIME_BCD(19 downto 16);
     when "011111" => DECODER_BCD <=  TIME_BCD(23 downto 20);
     when others   => null; 
   end case;
 end process;

TIME_BASE : CLK_SET     port map (CLK,RESET,SCAN_CLK,CLOCK);
SECOND    : COUNT_00_59 port map (CLOCK,RESET,'1'      ,CARRY_SEC,TIME_BCD(7 downto 0)); 
MINUTE    : COUNT_00_59 port map (CLOCK,RESET,CARRY_SEC,CARRY_MIN,TIME_BCD(15 downto 8));
HOUR      : COUNT_00_23 port map (CLOCK,RESET          ,CARRY_MIN,TIME_BCD(23 downto 16));
DECODER   : DECODER     port map (CLOCK,DECODER_BCD,SEGMENT);

end Behavioral;