Selecting a domain in clock domain cross

[feel_on_on]

clock domain cross:

1. two flip-flop was connected

2. FIFO,

please tell me how to select if two flip-flop or FIFO?

 

[Nandy]

clock domain crossing pdf

It depends on how much data has to be exchanged between the two domain.

 

[feel_on_on]

clock domain crossing

according to how much data? if data is so much ,do you select FIFO?

can you give me some specification in detail

 

[donald007]

cross domain clock

Hi,
I think it can have two kind.
First, "register access": you can use two flip-flop to construct a handshake protocal.

Second, "continue data exchange" (ex. DMA): you can use asynchronous FIFO.

 

[raju3295]

cross clock domain

Can you please elaborate the question, am finding difficulty in understanding the concept

 

[Nir Dahan]

cross clock synchronization + pdf

I would maybe first recommend to understand the problem itself and then finding the right solution.

It really depends on what you application is, some try to cross clock domains with minimum latency, others don't care about area overhead and might use overly complicated designs yet others don't seem to even care!! they claim the frequencies they handle are so low that the MTBF becomes very rare...

If you would like to explore a bit, try reading these posts and papers:

http://asicdigitaldesign.wordpress.com/2007/05/28/synchronization-uncertainty-and-latency/

http://asicdigitaldesign.wordpress.com/2008/04/21/clock-domain-crossing-an-important-problem/

http://asicdigitaldesign.wordpress.com/2007/05/18/another-synchronization-pitfall/

http://www.sunburst-design.com/papers/CummingsSNUG2001SJ_AsyncClk.pdf

http://asicdigitaldesign.wordpress.com/2007/06/01/synchronization-of-buses/

http://asicdigitaldesign.wordpress.com/2008/05/14/ring-buffers/

It is a lot of material, I know - but believe me, this is such an important problem that the reading time is time well spent. In each and every design I was part of, somewhere , someplace there was a some sort of synchronization problem involved. You will save a lot of time and raise your design standard by a few levels after grasping those concepts.


ND.

http://asicdigitaldesign.wordpress.com/