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

entity mouse is
    Port (
	       clk : in std_logic;
          reset : in std_logic;
          ps2_clk : inout std_logic;
          ps2_data : inout std_logic;
          left_button : out std_logic;
          right_button : out std_logic;
			 mov_x : out std_logic_vector(9 downto 0);
          mousex: buffer std_logic_vector(9 downto 0);
          mousey: buffer std_logic_vector(9 downto 0);
          data_ready : out std_logic;-- rx_read_o
          error_no_ack : out std_logic
			 );
end mouse;

architecture Behavioral of mouse is

constant TOTAL_BITS : integer :=33;  -- Number of bits in one full packet
-- The timer value can be up to (2^bits) inclusive.
constant WATCHDOG : integer :=320;-- Number of sys_clks for 400usec.160

type m2statetype is (m2_reset, m2_wait, m2_gather, m2_verify, m2_use, m2_hold_clk_l,
         m2_data_low_1, m2_data_high_1, m2_data_low_2, m2_data_high_2, m2_data_low_3,
		   m2_data_high_3, m2_error_no_ack, m2_await_response);

signal m2_state,m2_next_state : m2statetype;
--signal m3_state,m3_next_state : std_logic;

signal watchdog_timer_done : std_logic;--signals of commanding out to mouse 
signal q : std_logic_vector(TOTAL_BITS-1 downto 0);--bit sequence
signal bitcount : std_logic_vector(5 downto 0);--bit count

signal watchdog_timer_count : std_logic_vector(8 downto 0); --wait time

signal ps2_clk_hi_z : std_logic;     -- Without keyboard, high Z equals 1 due to pullups.
signal ps2_data_hi_z : std_logic;    -- Without keyboard, high Z equals 1 due to pullups.

signal fallsig,risesig : std_logic_vector(2 downto 0);
signal clean_clk : std_logic;       -- Debounced output from m1, follows ps2_clk.
signal rise,n_rise : std_logic;      -- Output from m1 state machine.
signal fall,n_fall : std_logic;     -- Output from m1 state machine.
signal output_strobe : std_logic;    -- Latches data data into the output registers
signal packet_good : std_logic;--check the whether the data is valid 
--signal x_increment : std_logic_vector(8 downto 0);
--signal y_increment : std_logic_vector(7 downto 0);
signal mouseyy,mousexx : std_logic_vector(9 downto 0);

begin
 
ps2_clk <= '0' when ps2_clk_hi_z='0' else 'Z';
ps2_data <= '0' when ps2_data_hi_z='0' else 'Z';

  ------------------------------------
  --detect ps2clk falling and rising edge
  ------------------------------------

  detect_ps2clkfall : process(clk,reset,ps2_clk)
  begin
    if reset='0' then
      fallsig <= "000";
    elsif clk'event and clk='1' then
      fallsig(0) <= ps2_clk;
	   fallsig(1) <= fallsig(0);
	   fallsig(2) <= fallsig(1);
    end if;
  end process;

  fall <= '1' when fallsig="110" else '0';

  detect_ps2clkrise : process(clk,reset,ps2_clk)
  begin
    if reset='0' then
      risesig <= "000";
    elsif clk'event and clk='1' then
      risesig(0) <= ps2_clk;
	   risesig(1) <= risesig(0);
	   risesig(2) <= risesig(1);
    end if;
  end process;

  rise <= '1' when risesig="001" else '0';

  --------------------------------------

------------------m2 State 
m2statech: process (reset, clk)
begin 
  if (reset='0') then
     m2_state <= m2_reset;
  elsif (clk'event and clk='1') then 
     m2_state <= m2_next_state;
  end if;
end process;

--m2 State transition logic
m2statetr: process (m2_state, fall,watchdog_timer_done,bitcount,ps2_data,packet_good)
begin
  -- Output signals default to this value, unless changed in a state condition.
  ps2_clk_hi_z <= '1';
  ps2_data_hi_z <= '1';
  error_no_ack <= '0';
  output_strobe <= '0';
  --data_out <= '0';

  case m2_state is
    when m2_reset =>    -- After reset, sends command to mouse.
      m2_next_state <= m2_hold_clk_l;
    when m2_wait =>
      if (fall='1') then
		   m2_next_state <= m2_gather;
      else 
		   m2_next_state <= m2_wait;
      end if;
    when m2_gather =>
      if (watchdog_timer_done='1') then  -- and (bitcount=TOTAL_BITS)
          m2_next_state <= m2_verify;
      else 
		    m2_next_state <= m2_gather;
      end if;
    when m2_verify =>
      --if (bitcount < TOTAL_BITS) then  --replace " packet_good='1' "
		   --m2_next_state <= m2_wait;
      --else 
		   m2_next_state <= m2_use;
      --end if;
    when m2_use =>
      output_strobe <= '1';
      m2_next_state <= m2_wait;

    -- The following sequence of 9 states is designed to transmit the
    -- "enable streaming mode" command to the mouse, and then await the
    -- response from the mouse.  
   when m2_hold_clk_l =>
      ps2_clk_hi_z <= '0';   -- This starts the watchdog timer!
      if (watchdog_timer_done='1') then  -- cut "and (clean_clk='0')"
		   m2_next_state <= m2_data_low_1;
      else 
		   m2_next_state <= m2_hold_clk_l;
      end if;
    when m2_data_low_1 =>
      ps2_data_hi_z <= '0';  -- Forms start bit, d[0] and d[1]
		--data_out <= '0';
      if (fall='1' and (bitcount = 2)) then
          m2_next_state <= m2_data_high_1;
      else 
		   m2_next_state <= m2_data_low_1;
      end if;
    when m2_data_high_1 =>
      ps2_data_hi_z <= '1';  -- Forms d[2]
		--data_out <= '1';
      if (fall='1' and (bitcount = 3)) then
          m2_next_state <= m2_data_low_2;
      else 
		   m2_next_state <= m2_data_high_1;
      end if;
    when m2_data_low_2 =>
      ps2_data_hi_z <= '0';  -- Forms d[3]
		--data_out <= '0';
      if (fall='1' and (bitcount = 4)) then
          m2_next_state <= m2_data_high_2;
      else 
		    m2_next_state <= m2_data_low_2;
      end if;
    when m2_data_high_2 =>
      ps2_data_hi_z <= '1';  -- Forms d[4],d[5],d[6],d[7]
		--data_out <= '1';
      if (fall='1' and (bitcount = 8)) then
          m2_next_state <= m2_data_low_3;
      else 
		    m2_next_state <= m2_data_high_2;
      end if;
    when m2_data_low_3 =>
      ps2_data_hi_z <= '0';  -- Forms parity bit
		--data_out <= '0';
      if (fall='1') then
		   m2_next_state <= m2_data_high_3;
      else 
		   m2_next_state <= m2_data_low_3;
      end if;
    when m2_data_high_3 =>
        ps2_data_hi_z <= '1';  -- Allow mouse to pull low (ack pulse)
      if (fall='1' and (ps2_data='1')) then
		    m2_next_state <= m2_error_no_ack;
      elsif (fall='1' and (ps2_data='0')) then
          m2_next_state <= m2_await_response;
      else 
		    m2_next_state <= m2_data_high_3;
      end if;
    when m2_error_no_ack =>
      error_no_ack <= '1';
      m2_next_state <= m2_error_no_ack;
    
    -- In order to "cleanly" exit the setting of the mouse into "streaming"
    -- data mode, the state machine should wait for a long enough time to
    -- ensure the FA response is done being sent by the mouse. 
    when m2_await_response =>
      --if (bitcount = 22) then
		    m2_next_state <= m2_verify;
      --else 
		   -- m2_next_state <= m2_await_response;
      --end if;
    when others => m2_next_state <= m2_wait;
  end case;
end process;
-----------------------------end m2 state

--This is the bit counter
bitcoun: process (reset, clk)
begin
  if (reset='0') then
     bitcount <= (others=>'0');  -- normal reset
  elsif (clk'event and clk='1') then
    if (fall='1') then
      bitcount <= bitcount + 1;
    elsif (watchdog_timer_done='1') then
       bitcount <= (others=>'0');  -- rx watchdog timer reset
	 end if;
  end if;
end process;

-- This is the shift data register
dataseq: process (reset, clk)
begin
  if (reset='0') then
     q <= (others=>'0');
  elsif (clk'event and clk='1') then
    if (fall='1') then
       q <= ps2_data & q(TOTAL_BITS-1 downto 1);
	 end if;
  end if;
end process;

-- This is the watchdog timer counter
-- The watchdog timer is always "enabled" to operate.
watchcount: process (reset,rise,fall, clk)
begin
  if ((reset='0') or (rise='1') or (fall='1')) then
    watchdog_timer_count <= (others=>'0');
  elsif (clk'event and clk='1') then
    if (watchdog_timer_done='0') then
      watchdog_timer_count <= watchdog_timer_count + 1;
	 end if;
  end if;
end process;

watchdog_timer_done <= '1' when (watchdog_timer_count=WATCHDOG-1) else '0';

--This is the logic to verify that a received data packet is "valid" or good.
packet_good <= '1';

-- Output the special scan code flags, the scan code and the ascii
outdata: process (reset, clk)
begin
  if (reset='0') then
    left_button <= '0';
    right_button <= '0';
    --x_increment <= (others=>'0');
    --y_increment <= (others=>'0');
  elsif (clk'event and clk='1') then
    if (output_strobe='1') then
      left_button <= q(1);
      right_button <= q(2);
      --x_increment <= '0' & q(19 downto 12);
      mouseyy <= not (q(6) & q(6) & q(30 downto 23)) + "1";
		mousexx <= q(5) & q(5) & q(19 downto 12);
	 end if;
  end if;						
end process;

cordinatex: process (reset, clk)
begin
  if (reset='0') then
 	 mousex <= "0110010000";  -- 400
  elsif (clk'event and clk='1') then
    if (output_strobe='1') then
	   if (mousex >= 599 and q(5)='0') then 
 	     mousex <= "1001010111";
		elsif (mousex <= 40 and q(5)='1') then
		  mousex <= "0000101000";
		else
		  mousex <= mousex + (q(5) & q(5) & q(19 downto 12));--q(5):xsign q(6):ysign
		end if;
	 end if;
  end if;						
end process;

cordinatey: process (reset, clk)
begin
  if (reset='0') then
	 mousey <= "0100101100";  -- 300
  elsif (clk'event and clk='1') then
    if (output_strobe='1') then
	   if (mousey >= 449 and q(6)='1') then  
 	     mousey <= "0111000001";  
		elsif (mousey <= 30 and q(6)='0') then
        mousey <= "0000011110";
		else
   	  mousey <= mousey + mouseyy; --(q(6) & q(6) & q(30 downto 23));
		end if;
	 end if;
  end if;						
end process;

mov_x <= mousexx;
data_ready <= output_strobe;

end Behavioral;