synthesis--speed falls down at virtex 4

[lmtg]

synthesis--speed

My design consists of severa blocks. Upon synthesis, each block achieves a max speed 0f about 500 M on virtex 4.When I put the design all together, the max possible speed falls down to 300M.

Is this normal?Or does thismean i'mdoing something wrong..

Plz Help ....

 

[sudhirkv]

Re: synthesis--speed

this is normal only. u can give constraints to the net which are giving more delay. so that u can make u r design to run more faster.

 

[lmtg]

synthesis--speed

Timing constraint you mean right? To path with max delay..

 

[sudhirkv]

yes. Usually if u dont give any constraints the synthesis tool will just like that will place and route the design. But if u give some contraints like if u give the clock frequency as a constriants, it will try to fit the design to satisfy the constraint.

If still u find any problem of slow clock you have to find out the longest path and u have to redesign such that u r delay is reduced.