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

entity PS2Tastatur is
	port(
		CLK: in std_logic;
		ps2c: inout std_logic;
		ps2d: inout std_logic;
		led: out std_logic_vector(15 downto 0));

end PS2Tastatur;

architecture Behavioral of PS2Tastatur is
	signal clkDiv : std_logic_vector (8 downto 0);
	signal Takt100kHz: std_logic;	 	-- 
	signal PS2_Takt, PS2_Dat: std_logic;
	signal shiftReg: std_logic_vector(10 downto 0):="00000000000";
	signal ct: std_logic_vector(7 downto 0);

begin

--=========================================================
--	Erzeugung eines 100kHz-Taktes	   (50MHz/2^9)
-----------------------------------------------------------
	Taktteiler: Process (CLK)
	begin
		if (CLK = '1' and CLK'Event) then 
			clkDiv <= clkDiv +1; 
		end if;	
	end Process;
-----------------------------------------------------------

	Takt100kHz <= clkDiv(8);

--=========================================================
-- Abtasten der eingehenden PS2-Signale
-----------------------------------------------------------
	Process (Takt100kHz)
	  begin
		if (Takt100kHz = '1' and Takt100kHz'Event) then
			ps2_Takt<= ps2c;
			ps2_Dat <= ps2d;
		end if;
	  end process;
--=========================================================
-- Datenübernahme in einem Schieberegister
-----------------------------------------------------------
	Process(ps2_Takt) 
	  begin																					  
		if (ps2_Takt = '0' and ps2_Takt'Event) then	-- fallende Flanke
			ShiftReg(10 downto 0) <= ps2_Dat & ShiftReg(10 downto 1);
			ct<=ct+1;
		end if;
	  end process;
--=========================================================
-- kombinatorische Ausgabe 
-----------------------------------------------------------
		led <= ct(4 downto 0) & ShiftReg;
-----------------------------------------------------------


end Behavioral;