Encounter Questions

(1) How to fix DRC errors reported by Encounter? I tried to use
"fixDRCViolation" and it completed w/o fixing any of the errors.
(Something I cannot figure out is why Encounter has to make those
errors in the first place as it has all the lef information).

(2) When I use addFiller with default options, there are still gaps
between placed standard cells, and those gaps are obviously large
enough for some fillers to fit in. Is there any way to force the tool
to fill as much as possible?

Any suggestion would be appeciated!

-Jerry

 

On Feb 10, 5:42 pm, want...@gmail.com wrote:

(1) How to fix DRC errors reported by Encounter? I tried to use
"fixDRCViolation" and it completed w/o fixing any of the errors.
(Something I cannot figure out is why Encounter has to make those
errors in the first place as it has all the lef information).

(2) When I use addFiller with default options, there are still gaps
between placed standard cells, and those gaps are obviously large
enough for some fillers to fit in. Is there any way to force the tool
to fill as much as possible?

Any suggestion would be appeciated!

-Jerry

Jerry,
I am an encounter & layout expert..
Your filler problem is bigger than the DRC prob.
Lets deal with this filler 1st
Did you select ALL the filler cells ? (1x)
Are you using the GUI?
Can you tell me who's IP you are using ?
Are all your cells width a multiple of the verticle routing grid?
Colin Doherty
axisic@gmail.com
p.s. where are you?

 

On Feb 12, 1:11 pm, Axi...@gmail.com wrote:

On Feb 10, 5:42 pm, want...@gmail.com wrote:

(1) How to fix DRC errors reported by Encounter? I tried to use
"fixDRCViolation" and it completed w/o fixing any of the errors.
(Something I cannot figure out is why Encounter has to make those
errors in the first place as it has all the lef information).

(2) When I use addFiller with default options, there are still gaps
between placed standard cells, and those gaps are obviously large
enough for some fillers to fit in. Is there any way to force the tool
to fill as much as possible?

Any suggestion would be appeciated!

-Jerry

Jerry,
I am an encounter & layout expert..
Your filler problem is bigger than the DRC prob.
Lets deal with this filler 1st
Did you select ALL the filler cells ? (1x)
Are you using the GUI?
Can you tell me who's IP you are using ?
Are all your cells width a multiple of the verticle routing grid?
Colin Doherty
axi...@gmail.com
p.s. where are you?

Colin:
Thanks for your input. I am a full time grad stduent at UVa. I
scripted the flow with all the filler cells chosen as filling
candidates (1x, 2x, 4x...) and that's why the result surprised me
since there are lots of gaps left that are large enough even for 4x. I
also noticed that some rows are nearly 100% filled while others are
very sparse. It's a standard cell design and the cell widths are
indeed multiples of the manufacturing grid (not sure if it's the
verticle routing grid you were talking about).

-J

 

[S. Badel]

(1) How to fix DRC errors reported by Encounter? I tried to use
"fixDRCViolation" and it completed w/o fixing any of the errors.
(Something I cannot figure out is why Encounter has to make those
errors in the first place as it has all the lef information).

It may be due to a congested routing. The router always creates drc during routing and corrects them
in a later pass. Maybe try increasing your floorplan size.

Otherwise try deleting the violating nets and rerouting them

editDeleteViolations
globalDetailRoute

Violations that cannot be corrected may be due to a bad cell design,

(2) When I use addFiller with default options, there are still gaps
between placed standard cells, and those gaps are obviously large
enough for some fillers to fit in. Is there any way to force the tool
to fill as much as possible?

This may be due to DRC violations preventing the placement of a cell. Try 'addFiller -no_DRC'

If you're running SOC42 or SOC52 base, there was an issue which has been fixed in SOC52USR1. The
workaround was to do 'setPlaceMode -snapConstraint' prior to adding fillers.


Hope this helps,

Stéphane

 

On Feb 14, 5:43 am, "S. Badel" <stephane.ba...@REMOVETHISepfl.ch>
wrote:

(1) How to fix DRC errors reported byEncounter? I tried to use
"fixDRCViolation" and it completed w/o fixing any of the errors.
(Something I cannot figure out is whyEncounterhas to make those
errors in the first place as it has all the lef information).

It may be due to a congested routing. The router always creates drc during routing and corrects them
in a later pass. Maybe try increasing your floorplan size.

Otherwise try deleting the violating nets and rerouting them

editDeleteViolations
globalDetailRoute

Violations that cannot be corrected may be due to a bad cell design,

(2) When I use addFiller with default options, there are still gaps
between placed standard cells, and those gaps are obviously large
enough for some fillers to fit in. Is there any way to force the tool
to fill as much as possible?

This may be due to DRC violations preventing the placement of a cell. Try 'addFiller -no_DRC'

If you're running SOC42 or SOC52 base, there was an issue which has been fixed in SOC52USR1. The
workaround was to do 'setPlaceMode -snapConstraint' prior to adding fillers.

Hope this helps,

Stéphane

Thanks Stephane! Sorry for the late follow-up. I am using SOC61 and I
think the DRC errors come from the lef file that I edited a lot
especially with the viarules. It's really surprising that the
technology toolkit I am using didn't come with a complete lef file. It
just has lef for each library and the lef header which doesn't have
layer and via rules.