keytx.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 unisim.vcomponents.all;
use work.key_Inter_pckg.all;

entity KeyTx 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
		 s        : out std_logic_vector(7 downto 0);  -- LED display
		 sccode  : out std_logic_vector(7 downto 0));
end keyTx;

architecture behave of keyTx 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

  -- LED segment activation patterns for various numbers and letters
  constant DIG_1    : std_logic_vector(7 downto 0) := "11111001";
  constant DIG_2    : std_logic_vector(7 downto 0) := "10100100";
  constant DIG_3    : std_logic_vector(7 downto 0) := "10110000";
  constant DIG_4    : std_logic_vector(7 downto 0) := "10011001";
  constant DIG_5    : std_logic_vector(7 downto 0) := "10010010";
  constant DIG_6    : std_logic_vector(7 downto 0) := "10000010";
  constant DIG_7    : std_logic_vector(7 downto 0) := "11111000";
  constant DIG_8    : std_logic_vector(7 downto 0) := "10000000";
  constant DIG_9    : std_logic_vector(7 downto 0) := "10010000";
  constant DIG_0    : std_logic_vector(7 downto 0) := "11000000";
  constant LETTER_A : std_logic_vector(7 downto 0) := "10001000";
  constant LETTER_b : std_logic_vector(7 downto 0) := "10000011";
  constant LETTER_C : std_logic_vector(7 downto 0) := "11000110";
  constant LETTER_d : std_logic_vector(7 downto 0) := "10100001";
  constant LETTER_E : std_logic_vector(7 downto 0) := "10000110";
  constant LETTER_F : std_logic_vector(7 downto 0) := "10001110";
  constant LETTER_G : std_logic_vector(7 downto 0) := "10010000";--**
  constant LETTER_h : std_logic_vector(7 downto 0) := "10001011";
  constant LETTER_i : std_logic_vector(7 downto 0) := "11101111";
  constant LETTER_J : std_logic_vector(7 downto 0) := "11100001";
  constant LETTER_K : std_logic_vector(7 downto 0) := "10001001";--***
  constant LETTER_L : std_logic_vector(7 downto 0) := "11000111";
  constant LETTER_n : std_logic_vector(7 downto 0) := "10101011";
  constant LETTER_M : std_logic_vector(7 downto 0) := "11001000";--****
  constant LETTER_o : std_logic_vector(7 downto 0) := "10100011";
  constant LETTER_P : std_logic_vector(7 downto 0) := "10001100";
  constant LETTER_q : std_logic_vector(7 downto 0) := "10011000";
  constant LETTER_R : std_logic_vector(7 downto 0) := "10101111";
  constant LETTER_s : std_logic_vector(7 downto 0) := "10010010";--***
  constant LETTER_T : std_logic_vector(7 downto 0) := "10000111";
  constant LETTER_u : std_logic_vector(7 downto 0) := "11100011";
  constant LETTER_V : std_logic_vector(7 downto 0) := "11000001";--***
  constant LETTER_W : std_logic_vector(7 downto 0) := "11000001";--***
  constant LETTER_X : std_logic_vector(7 downto 0) := "10001001";--***
  constant LETTER_y : std_logic_vector(7 downto 0) := "10010001";
  constant LETTER_Z : std_logic_vector(7 downto 0) := "10100100";--***
  constant LETTER_Enter : std_logic_vector(7 downto 0) := "01111111";--***
  constant LETTER_Space : std_logic_vector(7 downto 0) := "11110111";--***
  constant LETTER_BKSP  : std_logic_vector(7 downto 0) := "11111111";--***
  constant LETTER_ESC   : std_logic_vector(7 downto 0) := "11111110";--***
  constant LETTER_tab   : std_logic_vector(7 downto 0) := "11110110";--***
  constant ERROR 	      : std_logic_vector(7 downto 0) := "10111111";

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
      );

  -- this maps the scancode received from the keyboard into a pattern on the 7-segment display
  s_x <= DIG_1 when scancode = "00010110" else
         DIG_2 when scancode = "00011110" else
         DIG_3 when scancode = "00100110" else
         DIG_4 when scancode = "00100101" else
         DIG_5 when scancode = "00101110" else
         DIG_6 when scancode = "00110110" else
         DIG_7 when scancode = "00111101" else
         DIG_8 when scancode = "00111110" else
         DIG_9 when scancode = "01000110" else
         DIG_0 when scancode = "01000101" else
         LETTER_A when scancode = "00011100" else
			LETTER_b when scancode = "00110010" else
			LETTER_C when scancode = "00100001" else
			LETTER_d when scancode = "00100011" else
			LETTER_E when scancode = "00100100" else 		
			LETTER_F when scancode = "00101011" else
			LETTER_G when scancode = "00110100" else 		--**
			LETTER_h when scancode = "00110011" else
			LETTER_i when scancode = "01000011" else 	
			LETTER_J when scancode = "00111011" else
			LETTER_K when scancode = "01000010" else		--**
			LETTER_L when scancode = "01001011" else
			LETTER_M when scancode = "00111010" else 		--**
			LETTER_n when scancode = "00110001" else
			LETTER_o when scancode = "01000100" else
			LETTER_P when scancode = "01001101" else
			LETTER_q when scancode = "00010101" else   
			LETTER_R when scancode = "00101101" else
			LETTER_s when scancode = "00011011" else		--**
			LETTER_T when scancode = "00101100" else
			LETTER_u when scancode = "00111100" else
			LETTER_V when scancode = "00101010" else		--**
			LETTER_W when scancode = "00011101" else			--**
			LETTER_X when scancode = "00100010" else			--**
			LETTER_y when scancode = "00110101" else 			
			LETTER_Z when scancode = "00011010" else				--**
			LETTER_Enter when scancode = "01011010" else				--**
			LETTER_Space when scancode = "00101001" else				--**
			LETTER_BKSP  when scancode = "01100110" else				--**
			LETTER_tab   when scancode = "00001101" else	
			LETTER_ESC   when scancode = "01110110" else				--**
			ERROR;
  -- update the LED display
  process(clk)
  begin
	  if rising_edge(clk) then			
			if rdy = YES then
			  s <= s_x;                       -- update the display each time a scancode is received		
				sccode <= scancode;
			end if;
		 end if;
  end process;
end behave;