( ESNUG 412 Item 7 ) -------------------------------------------- [05/22/03]
From: Ze'ev Wurman <zeev=person company=easic fought psalm>
Subject: PrimeTime 2002.09 Has Major Trouble Annotating Nets With Overhangs
Hi John,
We have a bit unconventional situation where nets are made up of fixed-size
segments. Consequently, we frequently have "overhangs" when the net changes
direction, like in the following example:
J1 X
SRC>------+-------
|
|
|
|
------+-------------------->DEST
Y J2
We can extract the parasitics to DSPF without any problem. The resulting
parasitic tree which would normally look like:
SRC--r1---J1---r2----J2---r3--+--DEST
| | |
--- --- ---
--- c1 --- c2 --- c3
| | |
v v V
Looks like the following with the extra overhangs. As it should be.
cx cy
|--||-> |--||->
rx ry
| |
SRC--r1---J1---r2----J2---r3--+--DEST
| | |
--- --- ---
--- c1 --- c2 --- c3
| | |
v v V
But PrimeTime (2002.09, Linux) complains about about incomplete parasitics
and refuses to annotate such net.
Without the extra branches (cx/rx and cy/ry) PrimeTime works fine annotating
the net. Does anyone knows of a workaround to convince PrimeTime to
correctly interpret such annotation?
- Ze'ev Wurman
eASIC Corp. San Jose, CA
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|
