FIFO depth using in clock domain crossing

[nemolee]

clock domain crossing fifo

As we know, we have to use FIFO architecture in clock domain crossing. In order to reduce the die size, how depth in FIFO size become a good learning course.
Does anyone know if there is a formula to calculate the FIFO depth good enough for us?
Thanks.

 

[nickmu]

fifo depth

i want to know too

 

[zyphor]

how to calculate fifo depth

if the two clock has no relationship, minimum depth is 4 words, you may also see
some design is 3 words, but it is special design, not for general case

 

[niuniu]

clock domain crossing

it is design dependent. you should evaluate the preformance requirement. it there is not special conditon on latency, use the min size.

 

[bibo1978]

how to determine fifo size

A minimum depth of 4 in case of you r using quadrature flag, however if u r using extra bit in counters u can implement 3 word deep fifo, less than this is hardly do-able

 

[AlexWan]

fifo clock domains

Hi, nemolee

As I know, you can use the "Queueing Theory" to calculate the depth of FIFO. You can find this theory in many mathematical books.

Good Luck

 

[power-twq]

fifo depth calculation

The smaller fifo depth, the better.

if it is better is up to your design's requirement.

As we know, we have to use FIFO architecture in clock domain crossing. In order to reduce the die size, how depth in FIFO size become a good learning course.
Does anyone know if there is a formula to calculate the FIFO depth good enough for us?
Thanks.

 

[mike_bihan]

fifo depth

depth=3 will slightly impact read register hold-off time.

 

[tarkyss]

queuing theory fifo design

if the two clock has no relationship, minimum depth is 4 words,

if the two clock have some relationship, the depth?
for example, the write clock is 2 times of the read clock

 

[jackson_peng]

fifo clock crossing

Please specify your two clock domain. i don't believe there exist a general purpose formula on FIFO depth.

PS, I saw some paper use "Queueing Theory" on this. i believe it can be helpful

 

[hawk_chenbo]

how to find fifo depth

Say clock frequency in A domain is 100M, B is 80M. The time in the data transition process from A to B is 800ns.
In the period, 80 bytes are sent in A domain. The B domain can only receive 64 bytes. So the depth of FIFO(byte-wide) is 16.