Statemachine error

Hi I think i have a statemachine that makes a ibutton interface top communicating.

I think it is in the code below. Could some one have a look. On thing I found that DQ_IN is in input that is not clocked but is used for state selection.

I guess this could put the statemachine in an unconditioned state (metainstability) But i'm having a hard time proving this.

I can't find it in practice nor any documentation about this.

This is the code:

OneWireReset_machine: process(clk, MR)

-- machine variables

variable count: INTEGER range 0 to 1000;

variable smCnt: INTEGER range 0 to 32;

begin

if (MR = '1') then --synchronous reset

count:=0;

OneWireReset <= Idle;

pdr <= '1';

elsif (clk'event and clk = '1') then

if (clk_en = '1') then

case OneWireReset is

when Idle =>

count := 0;

if owr = '0' then

OneWireReset <= Idle;

elsif owr = '1' then

OneWireReset <= Reset_Low;

end if;

when Reset_Low =>

count := count +1;

pdr <= '1';

if count = 500 then

OneWireReset <= PD_Wait;

end if;

when PD_Wait =>

count := count +1;

if count = 515 then

OneWireReset <= PD_Edge;

end if;

when PD_Edge =>

count := count +1;

if DQ_in = '0' then -- Adapted for Granada situation

OneWireReset <= PD_Sample;

smCnt := 0;

elsif count = 560 then

OneWireReset <= PD_Sample;

smCnt := 0;

end if;

when PD_Sample =>

count := count +1;

smCnt := smCnt +1;

if smCnt = 30 then

pdr <= DQ_in; -- presence detect register

OneWireReset <= Reset_High;

end if;

when Reset_High =>

count := count +1;

if count = 1000 then

OneWireReset <= Reset_End;

end if;

when Reset_End =>

OneWireReset <= Idle;

when others =>

null;

end case;

end if;

end if;

end process;