setup and hold in multiple clocks

[designer_ec]

Hi,

If design has multiple clocks,so how to calculate the setup and hold calculation for multiple clocks.

thanks

 

[roy_ece]

hi ,
For Multiple clocks ,we have to know the edge of the clock that triggers flipflops.

Suppose if two clocks are A and B .
Then setup check is performed in the following manner:

The setup relationship is the closest distance between the launching clock edge (A) to the receiving clock edge (B) ,if closest distance is zero for some edges ,then take a non-zero closest distance.


The hold relationship is the closest distance between the launching edge (A) to the previous receiving edge (B)

 

[uditkumar1983]

HI Roy,
I am not getting, Please Explain Something More or if you are having any document Please upload that one or send me :
u1_kumar@yahoo.com

Thanks in Advance.......

 

[GoodMan]

Hi,
have any more data about it ?

 

[wice]

firstly,Provided that your design is a single cycle design in which you did not use multicycle constraint.
secondly,Provided that you used the rising edge of clock to trigger flip-flops.
thirdly,Provided that the multiple clocks are synchronous to each other.
Then ,i can give an answer to the question.
the setup is checked between the rising edge of the first stage clock and the rising edge of the second stage clock.

the hold is checked between the rising edge of the second stage clock and the rising edge of first stage clock.

 

[pradeep2323]

its not so clear from figure cud u explain bit clearly???????