lanes_selector.txt

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;

entity select_lane is
    Port (     game_clock : in  STD_LOGIC;
	               obst_in : in  STD_LOGIC;
           obstacle_1 : out  STD_LOGIC;
           obstacle_2 : out  STD_LOGIC;
           obstacle_3 : out  STD_LOGIC);
end select_lane;

architecture Behavioral of select_lane is
   signal linear_feedback_shift_register : std_logic_vector (15 downto 0) := "0010000010000001";
	signal linear_feedback_shift_register_next : std_logic_vector (15 downto 0) := "0010000010000001";
begin

   process(game_clock)
	begin  
		if (rising_edge(game_clock)) then
			linear_feedback_shift_register <= linear_feedback_shift_register_next;
		end if;
	   if (obst_in = '1') then
		   if ((conv_integer(linear_feedback_shift_register)) > 49152) then
		      obstacle_1 <= '1';
			   obstacle_2 <= '0';
		   	 obstacle_3 <= '0';
		   elsif (((conv_integer(linear_feedback_shift_register)) > 24576 ) and((conv_integer(linear_feedback_shift_register)) < 49152)) then
		      obstacle_1 <= '0';
		   	obstacle_2 <= '1';
		   	obstacle_3 <= '0';
		   elsif ((conv_integer(linear_feedback_shift_register)) < 24576) then
		    obstacle_1 <= '0';
	   		obstacle_2 <= '0';
	   		obstacle_3 <= '1';
	   	else
	   	   obstacle_1 <= '0';
	   		obstacle_2 <= '0';
	   		obstacle_3 <= '0';
	   	end if;
		else
		   obstacle_1 <= '0';
	      obstacle_2 <= '0';
	   	obstacle_3 <= '0';
	   end if;
	end process lfsr_seq;
	
	process(linear_feedback_shift_register)
	begin
	   linear_feedback_shift_register_next (15 downto 1) <= linear_feedback_shift_register (14 downto 0);
		linear_feedback_shift_register_next (0) <= linear_feedback_shift_register(15) xor linear_feedback_shift_register(5);
	end process lfsr_comb;

end Behavioral;