serial.vhd

something useful for communication,source code based on FPGA

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

--  Uncomment the following lines to use the declarations that are
--  provided for instantiating Xilinx primitive components.
--library UNISIM;
--use UNISIM.VComponents.all;

entity serial is
  port (
    clk    : in  std_logic;
    rst    : in  std_logic;
    input  : in  std_logic_vector(1 downto 0);
--	 tbaux  : out std_logic_vector(1 downto 0);
    output : out std_logic);
end serial;

architecture serial of serial is
  type states is (st0, st1);
  signal state : states;


  signal aux : std_logic_vector(1 downto 0);

begin

--tbaux <= aux;
  process(clk, rst)
  begin
    if rst = '1' then
      aux <= (others => '0');
		output <= '0';
    elsif clk'event and clk = '1' then
	   case state is
		   when st0 =>
			   aux <= input;
				output <= aux(0);
				state <= st1;
		   when st1 =>
			   output <= aux(1);
				state <= st0;
		end case;			
    end if;
  end process;
end serial;