keyvga.vhd

many application on kit SP-3: VGA, digital clock, counter, interface PS2....

library IEEE, unisim;
use IEEE.std_logic_1164.all;
use IEEE.NUMERIC_STD.all;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use work.key_Inter_pckg.all;
--library unisim;
--use unisim.vcomponents.all;
entity KeyVga is --100_000
  generic(FREQ : natural := 50000 );   -- frequency of main clock (KHz)
  port(clk  : in  std_logic;     -- main clock
		rdy  : buffer  std_logic;  
		 ps2_clk  : in  std_logic;           -- keyboard clock
		 ps2_data : in  std_logic;           -- keyboard data
		 cnt      : out std_logic_vector(4 downto 0);  -- LED display
		 sccode  : out std_logic_vector(7 downto 0));
end keyVga;

architecture behave of keyVga is
  
  constant YES : std_logic := '1';
  constant NO  : std_logic := '0';

  signal scancode  : std_logic_vector(7 downto 0);  -- scancode from keyboard
--  signal rdy       : std_logic;         -- indicates when scancode is available
  signal s_x       : std_logic_vector(7 downto 0);  -- next state of LED segments
  signal kbd_error : std_logic;         -- error receiving scancode from keyboard
  signal cntchar   : std_logic_vector(4 downto 0);  
 -- LED segment activation patterns for various numbers and letters
  
begin
  u400 : key_interface
    generic map( FREQ => FREQ )
    port map(clk      => clk,           -- clock for the keyboard interface
      rst      => kbd_error,            -- reset the keyboard intfc whenever there is an error receiving a scancode
      ps2_clk  => ps2_clk,              -- clock from the keyboard
      ps2_data => ps2_data,             -- serial data from the keyboard (valid on falling edge of ps2_clk)
      scancode => scancode,             -- the scancode received from the keyboard
      rdy      => rdy,                  -- indicates when a scancode from the keyboard is available
      error    => kbd_error  );         -- indicates an error in receiving a scancode from the keyboard
 -- update the LED display
  process(clk)
  begin
	  if rising_edge(clk) then			
			if rdy = YES then			
			  sccode <= scancode;
			  if cntchar < "01010" then
					cntchar <= cntchar + '1';
				else 
					cntchar <="00001";
				end if;
			cnt<= cntchar;
			end if;
		 end if;
  end process;
end behave;