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


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entity PS2_Controller is
Port (
	ps2_clk	: in std_logic;					-- linha de relogio PS2
	ps2_data	: in std_logic;					-- linhda de dados PS2
	rst		: in std_logic;
	clk		: in std_logic;
		 
	LED			: out std_logic;					-- LED sinaliza recepcao
	scan_code	: out std_logic_vector(7 downto 0);	-- tecla pressionada
	busy			: out std_logic;					-- flag de sincronizacao
	LED2			: out std_logic;
	LED3			: out std_logic
	);
end PS2_Controller;

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architecture Behavioral of PS2_Controller is

	signal byte		: std_logic_vector(7 downto 0);	-- byte PS2 recebido
	signal count33 : integer range 0 to 32;	-- 33 bits recebidos no total
	signal busyIn,pulse 	: std_logic;
	signal improve_signal	: std_logic_vector(7 downto 0);

begin

process(clk, rst)
begin
	if rst = '0' then improve_signal <= (others => '0');
	elsif rising_edge(clk) then
				improve_signal <= improve_signal(6 downto 0) &  ps2_clk;
				if improve_signal = "10000000" then pulse <= '1';
				else pulse <= '0';
				end if;
	end if;
end process;

process (pulse,rst)
begin
	if rst = '0' then count33 <= 0;
		busyIn <= '0'; scan_code <= (others => '0');
	elsif rising_edge(pulse) then			-- inicio de uma recepcao
		if (ps2_data = '0') then 
				if (busyIn = '0') then 
						busyIn <= '1';	
						count33 <= count33+1;			-- esperar start bit
				else null;
				end if;
		else null;
		end if;

		case count33 is
			when 1 to 8 => count33 <= count33+1; byte(count33-1) <= ps2_data;
			when 9 => count33 <= count33+1; scan_code <= byte; LED <= '0';
			when 10 => if (ps2_data = '1') then	count33 <= count33+1; -- STOP BIT
							else null;
							end if;
			when 11 => if (ps2_data = '0') then	count33 <= count33+1; -- START BIT 
							else null;
							end if;
			when 12 to 20  => count33 <= count33+1;
			when 21 => if (ps2_data = '1') then	count33 <= count33+1;  -- STOP BIT
							else null;
							end if;
			when 22 => if (ps2_data = '0') then	count33 <= count33+1;   -- START BIT
							else null;
							end if;
			when 23 to 31  => count33 <= count33+1;
			when 32 => if (ps2_data = '1') then	busyIn <= '0'; -- STOP BIT
								count33 <= 0;								
							else null;
							end if;				
			when others  => null;
		end case;
  end if;

end process;

busy <= busyIn;

LED <= '0';
LED2 <= '0';
LED3 <= '0';

end Behavioral;