library ieee;
use ieee.std_logic_arith.all;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity cognome is
port( clk,reset,enable : in std_logic;
      address_in       : in unsigned(7 downto 0);
      command_in       : in std_logic_vector(1 downto 0);
      address_out      : out unsigned(7 downto 0);
      memory_read      : out std_logic );
end cognome;

architecture STRUCT of cognome is

type stato is (idle,single,burst);
signal ns,cs       : stato;
signal addr,naddr  : unsigned(7 downto 0);

begin
  process(clk,reset)
  begin
    if reset = '0' then
       cs   <= idle;  
       addr <= (others => '1');
    else 
      if clk'event and clk='1' then
         if enable='0' then 
            cs   <= ns;
            addr <= naddr;
         end if;
      end if;
    end if;
  end process;

process(addr,cs,command_in,address_in)
    begin
      case cs is
        when idle =>  address_out <= (others => '1');
                      memory_read <='1';
					  
                      if command_in="01" then 
                         naddr <= address_in;
                      else
                         naddr <= addr;
                      end if;
                      
                      if command_in="00" then 
							ns <= idle;
                      elsif command_in="10" then
							ns <= single;
					  elsif command_in="11" then
							ns <= burst;
					  else 
							ns <= cs;
					  end if;

         
        when single =>  address_out <= addr;
                        memory_read <='0';
	         			naddr <= addr;
                      
                      	ns <= idle;

        when burst =>   address_out <= addr;
                        memory_read <='0';
	         			naddr <= addr+1;
                      
                        if command_in="00" then 
			    ns <= idle;
                        else
                            ns <= burst;        
                        end if;					  

	    -- In caso di malfunzionamenti il sistema viene riportato 
        -- nello stato idle
		when others =>  address_out <= (others => '1');
                        memory_read <='1';
	         	naddr <= addr;
                        ns <= idle;
	 end case;
   end process;

end STRUCT;