lcd.vhd

依元素开发板的示例程序

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

entity lcd is
    Port (clk:in std_logic;
	       sw:in std_logic_vector(7 downto 0);
	       l :out std_logic_vector(6 downto 0);
			 a :out std_logic_vector(3 downto 0));
end lcd;

architecture Behavioral of lcd is
  signal b:std_logic_vector(3 downto 0);
  signal count:std_logic_vector(1 downto 0);
  signal ll:std_logic_vector(6 downto 0);
  signal lll:std_logic_vector(6 downto 0);
  signal fclk:std_logic;
  signal fcount:std_logic_vector(3 downto 0);
begin

process(clk)
begin
  if clk'event and clk='1' then
    fcount<=fcount+1;
  end if;
end process;
fclk<=fcount(3);
process(fclk)
begin
  if fclk'event and fclk='1' then
    count<=count+1;
  end if;
end process;

process(count)
begin
  case count is
    when "00" => a<="0001";l<=ll;
	 when "01" => a<="0010";l<=lll;
    --when "10" => a<="0100";
	 --when "11" => a<="1000";
	 when others=> a<="0000";
  end case;
end process;

process(sw)
begin
  case sw(3 downto 0) is
    when "0000" =>ll<="0000001";--0
	 when "0001" =>ll<=not"0110000";--1
    when "0010" =>ll<=not"1101101";--2
    when "0011" =>ll<=not"1111001";--3
    when "0100" =>ll<=not"0110011";--4
    when "0101" =>ll<=not"1011011";--5
	 when "0110" =>ll<=not"1011111";--6
    when "0111" =>ll<=not"1110000";--7
    when "1000" =>ll<=not"1111111";--8
    when "1001" =>ll<=not"1111011";--9
	 when "1010" =>ll<=not"1110111";--a
	 when "1011" =>ll<=not"0011111";--b
    when "1100" =>ll<=not"1001110";--c
    when "1101" =>ll<=not"0111101";--d
    when "1110" =>ll<=not"1001111";--e
    when "1111" =>ll<=not"1000111";--f
	 when others =>ll<=not"0000000";
  end case;
end process;

process(sw)
begin
  case sw(7 downto 4) is
    when "0000" =>lll<="0000001";--0
	 when "0001" =>lll<=not"0110000";--1
    when "0010" =>lll<=not"1101101";--2
    when "0011" =>lll<=not"1111001";--3
    when "0100" =>lll<=not"0110011";--4
    when "0101" =>lll<=not"1011011";--5
	 when "0110" =>lll<=not"1011111";--6
    when "0111" =>lll<=not"1110000";--7
    when "1000" =>lll<=not"1111111";--8
    when "1001" =>lll<=not"1111011";--9
	 when "1010" =>lll<=not"1110111";--a
	 when "1011" =>lll<=not"0011111";--b
    when "1100" =>lll<=not"1001110";--c
    when "1101" =>lll<=not"0111101";--d
    when "1110" =>lll<=not"1001111";--e
    when "1111" =>lll<=not"1000111";--f
	 when others =>lll<=not"0000000";
  end case;
end process;

end Behavioral;