Answers Database

TNM attached to net between PAD and IBUF/BUFG not forward traced


Record #1715

Problem Title:
TNM attached to net between PAD and IBUF/BUFG not forward traced


Problem Description:
If a TNM attribute is attached to a net, normally that TNM is forward traced
until it reaches all flip-flops that connect to that net. Those flip-flops
then become part of that TNM group.
However, because of ambiguities in the .XNF format, a TNM attribute placed
on the net between the PAD and IBUF or BUFG will not be forward traced.
Instead, it will be placed on the PAD itself.


Solution 1:

Place the TNM on the net that is sourced by the output of the
IBUF or BUFG. Always avoid placing TNMs on the net that goes
to the PAD.




End of Record #1715