Answers Database

M1.3/1.4 TRACE: A DPRAM DPO to destination FROM:TO constraint is not analyzed


Record #3332

Product Family:  Software

Product Line:  Merged Core

Problem Title:
M1.3/1.4 TRACE: A DPRAM DPO to destination FROM:TO constraint is not
analyzed



Problem Description:
Keywords: Dual Port Ram, TIG, constraints, DPO, SPO

Urgency: Hot


A TNM attached to a DPRAM may not attach itself correctly
to the RAM if the SPO output is not connected. For example,
for the following path:

|--------|
| DPRAM  |
|     spo|---x
|	 |		   |----|
|     dpo|-----------------|D  Q|
|	 |		   |>	|
|--------|		   |----|
tnm=myram		  tnm=myflop

This path would be picked up by a PERIOD constraint. However,
a constraint such as "TIMESPEC TS_IG=FROM:myram:TO:myflop:TIG;"
will not be recognized (path still in PERIOD constraint ).
Even if the constraint is not a TIG ( a normal FROM:TO, for
instance), it will still not be recognized (PERIOD will still
control it).



Solution 1:

This is actually a MAP bug, and it is fixed in a M1.4 patch
on the FTP site. Go to: ftp://ftp.xilinx.com/pub/swhelp/M1.4_alliance
and download the appropriate "core" patch for your platform.




End of Record #3332