Assura-RCX : Do I really need LVS?

Hi,
I have a power-grid with a bunch of inputOutput pins for external
VDD and GND connections. I want to use assura-RCX to extract the R&C
parasitics of this grid. Can I directly run assura-RCX without having
to run LVS? If the answer is "NO", then how do I create a schematic for
a power grid (just wires) with all the inputOutput pins?

Trisha

 

As far as I know you can't.
Assura RCX needs at least one non parasitic device
to do an extraction.

As a suggestion if you have some metal R's in your
device library you can put them as a kind of dummy
devices on you power grid, so that you can run a
LVS and after it a parasitic extraction.

Bernd

 

No you don't. Indeed, RCX requires the device and netlist extraction
steps to be run, but the GUI does not allow you to run them without
doing the LVS in the same shot.

You'll just need to create your own RSF file, or tweak the one created
by the UI. It should look like

avParameters(
...
)
rcxParameters(
...
)
avDX()
avNX()
avRCX()

Alternatively, running LVS against a dummy schematic will also enable
the RCX UI - you don't need to care about the LVS results. If some
circumstances, it will not enable by itself - you just open the run and
it enables.

Stéphane

--
Related Sourcelink articles:
11085296
11085296
11156636
11176148

 

Actually, it seems not. I guess that devices are needed for LVS, not
RCX. Indeed, without devices LVS fails and complains about the netlist
being empty.

though I never tried it myself, sourcelink solution 11176148 claims that
it's possible to run RCX with no devices on the layout.

cheers,

Stéphane

 

I tried to create a dummy schematic (by importing a verilog file where
I just declared the inputOutput pins corresponding to VDD and GND pins
on the power-grid.) The LVS did not complain must except for couple of
mismatches. When I run the RCX from UI, I get the following errors:

*WARNING* at "capgen": Contact layer 'Cont' specified in the p2lvsfile
is not found in the lvsfile.
Forking: /tools/assura/bin/32bit/capgen -techdir
/gpdk_MIET_2.0/assura_gpdk_tech -lvs /layout/assura_run/run1.xcn -p2lvs
/gpdk_MIET_2.0/assura_gpdk_tech/p2lvsfile -p poly,allGate,diff
-canonical_res_caps -length_units meters -mos_diff_ap_nw -xgl
/layout/assura_run/run1
*FATAL* at "RCXspice": Unable to read
'/gpdk_MIET_2.0/assura_gpdk_tech/cap_coeff.dat', No such file or
directory
*WARNING* Bad return status from RCX script generator. Status 256

Any idea what am I doing wrong??

Trisha

 

Does it work if you have a normal schematic? I'd be surprised - it looks as if
you're pointing at a rules directory which doesn't have the RCX information (e.g
cap_coeff.dat). Perhaps you have to point at a different LVS setup to get the
RCX information?

Some of Assura RCX is set up on the fly, but most of the coefficients are
pre-computed (because that takes some time, and would be shared by all runs).

Regards,

Andrew.