EVEN / ODD COUNTER (Behavioral)

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use ieee.std_logic_unsigned.all;

Entity UP_COUNTER is

port(clr,clk,pr:in std_logic;Q:inout std_logic_vector(3 downto 0));

end UP_COUNTER;

Architecture behavioral of UP_COUNTER is

begin

process( clr,clk,pr,Q)

begin

if (pr ='0') then Q<="1111";

elsif (clr ='0') then Q<="0000";

--if we starts the counting after clearing the count, it works as Even Counter. 

--if we starts the counting after presetting the count, it works as Odd Counter.

elsif clk='0' and clk'event then

Q<=Q + 2;

end if;

end process;

end behavioral;