synchr.and asynchr.

Hi,

I have a question about synchr.and asynchr. systems.which one is
prefered and why?
I mean which one is recomended : 1)at every positive edge of clock we
check the reset or 2)we can reset at any time not necessarily at
posedge.

If you give me a link to know more it will be very helpful.
Thanks

 

[Mike Treseler]

maryam.darvishan@gmail.com wrote:

I have a question about synchr.and asynchr. systems.which one is
prefered and why?

If all else is equal, a synchronous design is
easier to verify using simulation and static
timing analysis.

I mean which one is recomended : 1)at every positive edge of clock we
check the reset or 2)we can reset at any time not necessarily at
posedge.

Both.
I use the asynch reset to give me a
single starting point for simulation.
Synchronous initialization is covered
by IDLE or INIT states which may occur
at any time.

If you give me a link to know more it will be very helpful.

http://groups.google.com/groups/search?q=treseler+reset+simulation+idle

-- Mike Treseler