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"GROUND && ! POWER": no POWER nets present

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casual

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I did a simple inverter layout & run Calibre LVS

here is the LVS extraction report


#############################################################
## ##
## C A L I B R E S Y S T E M ##
## ##
## C I R C U I T E X T R A C T I O N R E P O R T ##
## ##
#############################################################


REPORT FILE NAME: inverter3.lvs.report.ext
LAYOUT NAME: /app/project/CSM018IC/LVS/inverter3.calibre.db ('inverter3')
CREATION TIME: Mon Mar 8 15:21:17 2010
CURRENT DIRECTORY: /app/project/CSM018IC/LVS
USER NAME: kstan
CALIBRE VERSION: v2008.1_13.11 Fri Feb 22 15:14:30 PST 2008




WARNING: Invalid PATHCHK request "GROUND && ! POWER": no POWER nets present, operation aborted.


WARNING: Invalid PATHCHK request "POWER && ! GROUND": no POWER nets present, operation aborted.


WARNING: Invalid PATHCHK request "! POWER && ! GROUND": no POWER nets present, operation aborted.




---------------------------------------------------------------------------------------
In ERC warning:
ntap with no path to power
ptap with no path to ground


----------------------------------------------------------------------------------------
I just wonder whether is it ok or not... ?
I got LVS passed! & DRC passed!!

However i got the Warning in the LVS extraction & ERC report!!

NOTE that:
In schematic, the schematic has only in & out pin. Vdd! and gnd! are ground pins

In layout, I labeled in, out, vdd! and gnd!

Is it ok that I didnt use vdd & gnd pins in schematic?
 

Re: "GROUND && ! POWER": no POWER nets pre

casual said:
I did a simple inverter layout & run Calibre LVS

here is the LVS extraction report


#############################################################
## ##
## C A L I B R E S Y S T E M ##
## ##
## C I R C U I T E X T R A C T I O N R E P O R T ##
## ##
#############################################################


REPORT FILE NAME: inverter3.lvs.report.ext
LAYOUT NAME: /app/project/CSM018IC/LVS/inverter3.calibre.db ('inverter3')
CREATION TIME: Mon Mar 8 15:21:17 2010
CURRENT DIRECTORY: /app/project/CSM018IC/LVS
USER NAME: kstan
CALIBRE VERSION: v2008.1_13.11 Fri Feb 22 15:14:30 PST 2008




WARNING: Invalid PATHCHK request "GROUND && ! POWER": no POWER nets present, operation aborted.


WARNING: Invalid PATHCHK request "POWER && ! GROUND": no POWER nets present, operation aborted.


WARNING: Invalid PATHCHK request "! POWER && ! GROUND": no POWER nets present, operation aborted.




---------------------------------------------------------------------------------------
In ERC warning:
ntap with no path to power
ptap with no path to ground


----------------------------------------------------------------------------------------
I just wonder whether is it ok or not... ?
I got LVS passed! & DRC passed!!

However i got the Warning in the LVS extraction & ERC report!!

NOTE that:
In schematic, the schematic has only in & out pin. Vdd! and gnd! are ground pins

In layout, I labeled in, out, vdd! and gnd!

Is it ok that I didnt use vdd & gnd pins in schematic?

connect ntap to VDD and ptap to VSS to prevent latch-up. Note that you should put as many ntap and ptap as the area permits.
 

Re: "GROUND && ! POWER": no POWER nets pre

maybe you have to change the layer for the pin name (that text you can read). for some PDK it has to be "drawing", but can be "pin" or "label" for the other.
 
Re: "GROUND && ! POWER": no POWER nets pre

If you have VDD! in the layout, does that match any of the LVS POWER NAME statements in the rulefile?

That error message means that no nets were found that qualify as "power" nets during connectivity extraction, and then the PATHCHK operation couldn't proceed.

The PATHCHK operation is in there to check for certain kinds of ERC style errors.
 

i think the warnings can be waived since LVS is clean
 

Re: "GROUND && ! POWER": no POWER nets pre

casual said:
i think the warnings can be waived since LVS is clean

erc result says that wells are not properly tied to its corresponding voltage level.
 

Go to 'LVS Options' page, enter the name of powers, and grounds then rerun your LVS, hope it helps.

-San H
 
I agree with protonixs - unless you know what is going on never waive anything!
 

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