lcdkey.vhd

12864图形点阵液晶驱动vhdl程序

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

--  Uncomment the following lines to use the declarations that are
--  provided for instantiating Xilinx primitive components.
--library UNISIM;
--use UNISIM.VComponents.all;

entity lcdkey is
    Port ( lcd_lightkey : in std_logic;
           lcd_modekey : in std_logic;
           lcd_lightbuf : out std_logic;
           lcd_modebuf : out std_logic_vector(1 downto 0);
           sysclk : in std_logic);
end lcdkey;

architecture Behavioral of lcdkey is

signal shiftlightkey,shiftmodekey:std_logic_vector(15 downto 0);
signal lightbuf:std_logic;
signal modebuf:std_logic_vector(1 downto 0);
signal counter:integer range 0 to 500000000; 

begin

key_handle:
process(sysclk)
begin
  if sysclk'event and sysclk='1' then 
    counter<=counter+1;
	 shiftlightkey<=lcd_lightkey & shiftlightkey(15 downto 1);
    shiftmodekey<=lcd_modekey & shiftmodekey(15 downto 1);
    if shiftlightkey=x"0001" then
      lightbuf<=not lightbuf;
    end if;
    if shiftmodekey=x"0001" then
      modebuf<=modebuf+1;
	 elsif counter>=250000000 then
	   counter<=0;
		modebuf<=modebuf+1;
    end if;
  end if;
end process;

lcd_lightbuf<=lightbuf;
lcd_modebuf<=modebuf;

end Behavioral;