Feedback mux created for signal data

[valentin tihomirov]

Sinplify shows the following warnings

Feedback mux created for signal data[1:0]. Did you forget the set/reset
assignment for this signal?
Feedback mux created for signal data[3:0]. Did you forget the set/reset
assignment for this signal?
Feedback mux created for signal data[4:0]. Did you forget the set/reset
assignment for this signal?
Feedback mux created for signal data[7:0]. Did you forget the set/reset
assignment for this signal?



on this code:


architecture RTL of SHIFT_REGISTER is
signal DATA: STD_LOGIC_VECTOR(SIZE-1 downto 0);
begin
REG: process (CLK, RESET)
variable BitCnt: Integer range 0 to 8;
begin
if RESET = '1' then -- WARNINGS on this line
null;
DATA <= (others => '-');
elsif Rising_Edge(CLK) then
if ENABLE = '1' then
if LOAD = '1' then

-- VHDL not working for SIZE=1
-- DATA <= SIN & DATA (SIZE - 1 downto 1);

if SIZE = 1 then
DATA(0) <= SIN;
else
DATA <= SIN & DATA (SIZE - 1 downto 1);
end if;

end if;
end if;
end if;
end process REG;

POUT <= DATA;

end RTL;

 

[trican]

Is this because you dont specify what what happens when enable and loa
equal 0. Though I could be wrong

 

[Thomas Stanka]

if RESET = '1' then -- WARNINGS on this line
null;
DATA <= (others => '-');

Why do you use the null statement?

It seems that your synthesis tool didn't come along with reset to
don't-care. So use a dedicated set or reset. I bet your results will
be fine than.

bye Thomas