RING COUNTER (4-Bit) -(Behavioral)

library ieee;

use ieee.std_logic_1164.all;

Entity R_COUNTER is

port(clr,clk,pr:in std_logic;Q0,Q1,Q2,Q3:out std_logic);

end R_COUNTER;

Architecture behavioral of R_COUNTER is

signal temp : std_logic_vector(3 downto 0):="0001";

begin

process( clr,clk,pr)

begin

if (pr ='0') then Q0<='1';Q1<='1';Q2<='1';Q3<='1';

elsif (clr ='0') then Q0<='0';Q1<='0';Q2<='0';Q3<='0';

elsif clk='1' and clk'event then

temp<=temp(0) & temp(3 downto 1);

Q0<=temp(3); Q1<=temp(2); Q2<=temp(1); Q3<=temp(0);

end if;

end process;

end behavioral;