Placing FF's Relative to RAMB4s (xilinx)

[Morten Leikvoll]

My design places the FF in front of a RAMB4 on a VirtexE strangely. I have a
macro and I place all the RAMB4's (6 in total, 2 in each macro) on one
column by using for example LOC=RAMB4_R0C2:RAMB4_R7C2.
Now I can not find an easy one to place close to their RAMs without
specifying for each macro separately. I want to place the FF's in front of
the data and address inputs as close as possible (delay wise) to these
RAMB4's. Is there an easy way to do this?

 

[John_H]

"Morten Leikvoll" <m-leik@online.nospam> wrote in message news:<rI0hb.29235$os2.423755@news2.e.nsc.no>...

My design places the FF in front of a RAMB4 on a VirtexE strangely. I have a
macro and I place all the RAMB4's (6 in total, 2 in each macro) on one
column by using for example LOC=RAMB4_R0C2:RAMB4_R7C2.
Now I can not find an easy one to place close to their RAMs without
specifying for each macro separately. I want to place the FF's in front of
the data and address inputs as close as possible (delay wise) to these
RAMB4's. Is there an easy way to do this?

This is fixed for Virtex-II(Pro) and Spartan-3 (see
http://www.xilinx.com/bvdocs/appnotes/xapp416.pdf ) but you're
probably locked in to doing the flop and RAM placement manually for
Virtex-E. I've gone down this path myself.

Look forward to using the new parts!