entity Stepper_Motor_Controller is
    Port ( clk : in  STD_LOGIC;	   -- input to determine spped of rotation
           rst : in  STD_LOGIC;    -- resets and initializes the circuit
           en  : in  STD_LOGIC;    -- determine whether motor rotating or holding
           dir : in  STD_LOGIC;    -- motor direction control 
 
           ph  : out STD_LOGIC_VECTOR(4 downto 1) -- output to phase 1 to 4 motor			  
	 );
end Stepper_Motor_Controller;

architecture Behavioral of Stepper_Motor_Controller is
	signal   step_pattern : std_logic_vector(7 downto 0):= "11100000"; --initial value puts one LED on near the middle.
 
begin
	process(clk,rst) begin
		if rst = '1' then
			step_pattern <= "11100000";
 
		else
			if clk'event and clk = '1' then 
			-- If clk event occours then shift
				if en = '1' then 
					if dir = '1' then
						step_pattern <= step_pattern(6 downto 0) &amp; step_pattern(7);
					else
						step_pattern <= step_pattern(0) &amp; step_pattern(7 downto 1) ;
					end if;
				end if;
			end if;
		end if;
	end process;
 
	-- Update values to the phases
	ph(1) <= step_pattern(0);
	ph(2) <= step_pattern(6);
	ph(3) <= step_pattern(4);
	ph(4) <= step_pattern(2);			
 
end Behavioral;