[vlsi-nastava:2009] - greska u quartus-u by Nemanja Ilic <nemanja.ilic.81@gmail.com>

Zdravo svima,

Da li je neko mozda imao istu gresku ili mozda zna resenje ovog problema...
Gledao sam u Quartus-ovom helpu i na internetu ali nisam nasao resenje.

Error: The node "operational_unit:unit_op|MAR:unit_MAR|O_tmp" has 
multiple drivers due to the constant driver

Evo ga i kod MAR-a:

library ieee ;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.std_match;

entity MAR is
   generic (n: natural := 18);
   port
   (
       I1        : in std_logic_vector (1 downto 0);        -- PAGE bits
       I0        : in std_logic_vector (n-3 downto 0);    -- IBUS bits
       clk        : in std_logic;
       ld        : in std_logic;
       inc        : in std_logic;
       en        : in std_logic;                            -- enable 
tristate driver
       O        : out std_logic_vector (n-1 downto 0)    -- out to ABUS
   );
end MAR_new2;

architecture behaviour of MAR is
   signal O_tmp : std_logic_vector (n-1 downto 0);
begin
   process (clk)
   begin
       -- wait on clk's rising edge
       if (clk'event and std_match(clk, '1')) then
           if (std_match(ld, '1')) then
               O_tmp(n-1 downto n-2) <= I1;
               O_tmp(n-3 downto 0) <= I0;
           end if;
           if (std_match(inc, '1')) then
               O_tmp <= O_tmp + '1';
           end if;   
       end if;
       -- tristate driver
       if (std_match(en, '1')) then
           O <= O_tmp;
       else
           O <= (O'range => 'Z');
       end if;
   end process;
end behaviour;

Hvla unapred,
Nemanja