On May 25, 2:28*pm, Andy <jonesa...@comcast.net> wrote:
> Weng,
>
> You've told the synthesizer that state2_ns (the combinatorial signal,
> not the register) has to remember its previous value under certain
> circumstances, so it generates a latch to remember the value.
>
> Your choices to avoid the latch include a) avoiding combinatorial
> processes, b) including a default assignment (perhaps from the output
> of the associated register) in combinatorial processes, or c) making
> sure every possible execution path through the process results in all
> driven signals being assigned a value (and not just to themselves).
>
> I always choose (a). If you just have to use a combinatorial process,
> then (b) is much easier to read/write/verify/review than is(c).
>
> Andy

Hi Andy,
"You've told the synthesizer that state2_ns (the combinatorial signal,
not the register) has to remember its previous value under certain
circumstances, so it generates a latch to remember the value."

You are right and I understand it. I am interested in your method a.
Could you give me an example on how to use your method a. in the above
situation.

Thank you.

Weng