Tuesday, January 06, 2009     Register | Login | Search | Contact Us
     
   
     
     

Many of you already received communications about the move of the Cadence user community into cadence.com. And many of you have already joined, with over 4000 registrations in the first two weeks.

The new Cadence Community enhances the ability of Cadence users to connect and collaborate. In addition to moving the community into cadence.com -- enabling single sign-on for community, Sourcelink and Cadence events -- the new site is organized around nine technology segments, giving you easy access to product information, training, forums and blogs. Some of the new features include:
  • Ability to respond to posts via e-mail
  • Technology-specific blogs
  • Latest Web 2.0 social networking capabilities
  • Public profile options
  • Private messaging
  • Friends lists
Visit the new Cadence Community today at www.cadence.com/community and join the discussions!

Registration note: Due to the scope of the enhancements and the new SSO registration system, we were not able to migrate existing cdnusers.org member accounts. So new registrations are required, but this enables a broader set of functionality we think you'll enjoy.

Forum note: Under the guidance of forum moderators, we have taken the 20+ cdnusers.org forums and consolidated them into 11 forums on the new site. Posts have been brought over so you can leverage that posting history. CDNusers forums will be set to read only starting 7/30, and cdnusers.org will be redirected to the new community on 8/4.

Best regards,
Mike and Tom

Michael A. Catrambone - Steering Committee Chairman
Distinguished Engineer
PCB/Mechanical
UTStarcom, Inc.

Tom Diederich
Cadence Community Manager
Home
Forums
Forums > Digital IC > Synthesis and test

Subject: How do you find the driving cell?
Posting to forums is available to community members only.
Login or Register
Rate this topic:
   
Author Messages
ssunder@sioptical.com
Posts: 24
Online: User is Offline
2/04/2008 7:11 AM  
All -

How do you get the driver cell name of a net or hierarchical pin? I have tried the following commands -

fanin -structural -max_logic_depth 1 [get_attr drivers [find / -net XX]]

gives me the input pins of the fanins. I want to get the hierarchical name of output pin of the driving cell in question.

Any suggestions?

Thanks,

Sanjay
synthman
Posts: 17
Online: User is Offline
2/04/2008 7:22 AM  
Hello Sanjay,
You specify only 1 logic depth of a driver pin, which is an output pin, that's why so see the input pins. Try max_logic_depth of 2.
ssunder@sioptical.com
Posts: 24
Online: User is Offline
2/04/2008 7:52 AM  
Synthman -

Thanks,
go_rc
Posts: 1
Online: User is Offline
2/05/2008 10:51 AM  

Hi,

I don't think you want a logic depth of 2 here. If the result of [get_attr drivers] is already a leaf driver, then you already have your result. However if [get_attr drivers] returns a hierarchical boundary pin (and I'm assuming this is the tricky case you need to handle), then you want to get the fanin with the max PIN depth set to 1. Below is some code to help distinguish between the hierarchical boundary pin case and the trivial case.

Hope this helps...

- Denis

proc is_hier_boundary {pin} {
return [expr {[basename [dirname [dirname [dirname $pin]]]] eq "instances_hier"}]
}

proc leaf_driver {net} {
set drvrs [get_attribute drivers $net]
if {! [llength $drvrs]} {
return [list]
}

# get the first driver of the net (in case there are many)
# could loop over all drivers instead
set drvr [lindex $drvrs 0]

if {[is_hier_boundary $drvr]} {
# this is a hierarchical boundary, trace to find the leaf driver
return [fanin -structural -max_pin_depth 1 $drvr]
}

# the net is already driven by a leaf driver
return $drvr
}
ssunder@sioptical.com
Posts: 24
Online: User is Offline
2/05/2008 11:13 AM  
Many thanks, this is what I was looking for.

Sanjay
Posting to forums is available to community members only.
Login or Register
Forums > Digital IC > Synthesis and test > How do you find the driving cell?


ActiveForums 3.6
     
Copyright 2006 Cadence Design Systems, Inc.