Custom IC SKILL - Recent Threads

How do I create connectivity through derived layers?

MSchuldt — Tue, 25 Aug 2026 13:24:58 GMT

I'm writing the techfile for a process, and I have a very special via that has a known top metal, known via layer, but it can land on any of six metal layers. I have defined the top metal, via, and the six lower metals in my techfile, and I'm now trying to create the via definition.

techDerivedLayers(
( BM1 1001 (M1 'or M2) ) ; M1-M6 are standard layers, defined in layerDefinitions
( BM2 1002 (M3 'or M4) )
( BM3 1003 (M5 'or M6) )
( BM4 1004 (BM1 'or BM2) )
( BOTMET 1000 (BM4 'or BM3) )
) ; end techDerivedLayers

viaDefs(
standardViaDefs(
( TETHER BOTMET TOPMET (VIA 5.0 5.0) ; TOPMET and VIA are standard layers, defined in layerDefinitions
( 1 1 (1.0 1.0) )
(0.0 0.0) (0.0 0.0) (0.0 0.0) (0.0 0.0) (0.0 0.0) )
) ; end standardViaDefs
) ; end viaDefs

When I try to load my techfile, I see:

*WARNING* (TECH-2000212): techCreateStdViaDef: Invalid layers.

And it does not define the via. If I replace BOTMET in the via definition with a standard layer, everything is defined properly.

What is the correct way to create a via using a derived layer, or a via which connects to multiple things in different contexts?

M1-6 are local interconnect-ish layers. The TOPMET and VIA layers are a bit like a staple - TOPMET does not ever touch anything but VIA. This via is being defined for connectivity (use in virtuosoDefaultExtractorSetup), not for use in actual layout. Layout will use a staple pcell which is not constrained to Manhattan geometries. One side of the staple might land on M1, and the other side might land on M6.

Or maybe I'm asking the wrong question entirely. How do I define the connectivity of this staple that can land on six different metals? Or do I need to stop being lazy and create six different via definitions for every flavor of staple?

Any node - Skill for the automatic ruler creation of user-defined lengths ( Working Fine)

yogeshjaiswalCAD — Tue, 25 Aug 2026 04:22:59 GMT

Greetings All,

I am grateful for your assistance whenever I am in need. I aspire to contribute by enriching our community, as we consistently work to strengthen our connections.

After a detailed assessment of this code, I can affirm that it is an exemplary GUI-focused solution. It requires only the entry of the specified ruler length through the GUI and the binding key to be established just one time

/***************************************************************
* YOGI_PRULER
* 1. Load code in CIW followed by the procdeure name yogi_pruler_dim()
* 2. Dimension GUI appears
* 3. Enter exact dimension in um
* 4 Click exact first point (Start Point)

* 5 Click anywhere for the second point in the direction you want to create the ruler ( X-Dir or Y-Dir)

* 6. Exact measurement is created
***************************************************************/
;; =============================================================================
;; MAIN ACTION CALLBACK: This handles drawing the ruler based on the form's value
;; =============================================================================
procedure(yogi_pruler_action_cb(form)
let((win cv dim p1 p2)
;; Get the current active window and its layout cellview content
win = hiGetCurrentWindow()
cv = geGetWindowCellView(win)

;; Extract the target numeric dimension value directly from the user form
dim = form->dimField->value

;; STEP 1: Ask the user to click the initial starting point of the ruler
p1 = enterPoint(?prompts list("Click the starting point for your ruler"))

when(p1
;; Convert the raw screen cursor coordinates to actual layout canvas coordinates
p1 = geWindowToEditPoint(win p1)

;; STEP 2: Ask the user to click a second point to determine the drawing direction
p2 = enterPoint(?prompts list("Click any point to indicate drawing direction"))

when(p2
;; Convert the second screen coordinates to layout canvas coordinates
p2 = geWindowToEditPoint(win p2)

;; STEP 3: Identify whether the user moved more Horizontally or Vertically
if( abs(car(p2) - car(p1)) >= abs(cadr(p2) - cadr(p1)) then

;; --- HORIZONTAL ROUTE ---
;; If second click is to the right, project rightward. Otherwise, project leftward.
if(car(p2) >= car(p1) then
p2 = list(car(p1) + dim cadr(p1))
else
p2 = list(car(p1) - dim cadr(p1))
)
else
;; --- VERTICAL ROUTE ---
;; If second click is higher, project upward. Otherwise, project downward.
if(cadr(p2) >= cadr(p1) then
p2 = list(car(p1) cadr(p1) + dim)
else
p2 = list(car(p1) cadr(p1) - dim)
)
)

;; STEP 4: Draw the fixed-dimension measurement ruler on the active layout canvas
leCreateMeasurement(cv list(p1 p2))
)
)
)
)

;; =============================================================================
;; MAIN EXECUTION FORM: Creates the user interface dialog box and displays it
;; =============================================================================
procedure(yogi_pruler_dim()
let((dimField)
;; Create a clean text box field specifically meant for decimal/float entries
dimField = hiCreateFloatField(
?name 'dimField
?prompt "Ruler Dimension:"
?value 1.0
)

;; Construct the overall graphical user interface window wrapper
hiCreateAppForm(
?name 'yogiPrulerForm
?formTitle "Yogi Precision Ruler"
;; Places the input box at dynamic positioning layout coordinates
?fields list(list(dimField 0:10 300:30 110))
;; Automatically triggers our simplified callback function when user clicks OK/Apply
?callback "yogi_pruler_action_cb(hiGetCurrentForm())"
?buttonLayout 'OKCancelApply
)

;; Pop the completed dialog interface onto the user's workspace screen
hiDisplayForm(yogiPrulerForm)
)
)

I will wait for your response ,Once again thanks for warm gesture

Have a pleasant day!

Cheers & regards,

Yogesh Jaiswal

How can a concatenated string be transformed into a variable name?

SZ20260803361 — Thu, 20 Aug 2026 09:07:56 GMT

I want to set a variable name that can change over time. For example:
item=""
lists=setof(i parseString(getCurrentTime() "") i!) =" "&&i! =":")
foreach(elem lists
item=strcat(item elem)
)
I received the item with the code "Aug201706212026".
I want to replace the "item" in the variable name "a_item" with "Aug201706212026", so that the final variable name becomes "a_Aug201706212026". How can I do this? I tried using `setq(stringToSymbol(strcat("a_" item)) 5)`, but this caused an error. How should I proceed?

How to extract only highest metal Power/Ground/Bulk routing from top-level hierarchy using SKILL/Python in Virtuoso Studio IC 23.1?

AR202509246930 — Wed, 19 Aug 2026 06:01:36 GMT

Hello Cadence Community,

I am using Cadence Virtuoso Studio IC 23.1 and I am trying to create an automation flow to extract only the highest metal routing shapes for Power/Ground/Bulk nets from a top-level layout.

I want the script to automatically identify Power, Ground, and Bulk nets from the layout/database, without asking the user to manually provide net names.

For example, the script should automatically recognize nets like:

Power nets: VDD, VDD1, VDD2...etc.
Ground nets: VSS, VSSA, VSSB, etc.
Bulk/Well nets: NWELL, DNWELL, BULK, etc.
I am looking for the best way to identify them using net properties, terminal types, global nets, inherited connections, or any recommended Virtuoso database API.
Main challenge
In some designs, the top-level cell may only contain pins for these nets, while the actual metal routing is present inside lower-level sub-blocks.

So, I do not want to extract only the top-level pin shapes. I want to traverse the hierarchy and identify where the actual routing metal exists for the auto-detected PG/Bulk nets.

Warning while using asiSelectInst

SK202511261716 — Thu, 06 Aug 2026 15:10:04 GMT

I'm developing a form which at a certain point needs to allow the user to select an instance from their schematic. I then need to fetch the database object of that instance to do some further processing. I'm using asiSelectInst for this, in the following callback from a button on my form:

(procedure selectDUT(field scope)

(sevOpenSchematic (axlGetToolSession sess testname))

(asiSelectInst 'mydutfield ?prompt "select instance..." ?form myform ?tab (list 'mytabs 'page1))

)

"mydutfield" is an uneditable string field. I gave it a callback which fetches the database instance, so whenever asiSelectInst changes the value of the field, the callback is initiated:

(procedure fetchDUTInst(field scope)

(let

(

(cv (geGetEditCellView))

inst

)

(setq inst (car (exists obj cv->instances (equal obj->name (car (last (parseString scope->mydutfield->value "/")))))))

...

)

This works like a charm....almost. Sometimes, when I open the form for the first time, asiSelectInst fails with the following warning, printed to the CIW:

*Warning* No window and/or doneProc argument passed to "astiSelectInst", selection not started

The value in mydutfield doesn't change, and the callback is not executed. If I immediately try again, it works no problem, and continues to work all subsequent times. I've not been able to determine the exact conditions under which it fails, but it always seems to be when the form/maestro view is first opened.

Am I doing something wrong here?

I'm on version IC23.1-64b

Looking for a SKILL/Python Script to Automatically Run Schematic Netlist in Virtuoso IC23.1

AR202509246930 — Tue, 04 Aug 2026 09:36:59 GMT

Hi Community,

I am using Cadence Virtuoso IC23.1 and am looking for a SKILL or Python script that can automatically run schematic netlisting by simply providing the library name and cell (schematic) name as inputs.

The requirement is to run the netlisting process without opening the schematic in the Virtuoso GUI or in the background. Ideally, the solution should:

Accept library name and cell/schematic name as inputs.
Run the schematic netlisting automatically.
Avoid opening any schematic window.
Support batch/automated execution.

Has anyone implemented something similar or know of any available SKILL APIs, Python scripts, or examples that can achieve this in Virtuoso IC23.1?

how to use variable in defcell

MorrisDH — Tue, 28 Jul 2026 19:38:29 GMT

I am open to suggestions if there is a better way to create a symbol cellview but the following is what I am using.

defcell("realCellName" defSymbol( nil ) )

It works fine for a basic symbol with no pins which is all I need. It creates a symbol cellview under the cell "realCellName".

The following does not work as expected.

cellName = "realCellName"

defcell(cellName defSymbol( nil ))

It creates a new cell named "cellName" instead of parsing the variable. Is it not possible for defcell to recognize variables?

Or maybe there is a better way to create simple symbol cellviews.

Thanks

Hi, How to hide a set of parameter section in pcell generation using "pcDefinePCell()" fuction

Ganesh B — Sun, 26 Jul 2026 17:44:37 GMT

Hi, How to hide a set of parameter section in pcell generation using "pcDefinePCell()" fuction. Can anyone help?

Just like this.

how to make a cellview read-only?

JJ202502261359 — Thu, 23 Jul 2026 08:44:10 GMT

I want to implement the "Make Read Only" function found in the Virtuoso menu using SKILL.

Virtuoso must revert to the last saved state without closing the layout GUI.

1. dbPurge() has an issue where the GUI window closes.
2. When proceeding with dbReopen("r") after hiUndo() multiple times,
the undo operation is incomplete due to the limit on the number of undo steps.
3. If I open a layout in "r" mode and then modify it using `dbCreatePath`, the action cannot be undone.

Based on points 1, 2, and 3, implementing "Make Read Only" using Skill proved difficult.

Is there a possible way to do it

Automatization of Maestro view and schematic (testbench) for simulation of multiple results

OG202503213520 — Tue, 21 Jul 2026 10:08:00 GMT

Hello,
I have a design that I need to verify and do the simulation , to give an idea , it had multiple inputs and outputs and they depend on internal values. I need to simulate each input with different output to see the delay.

Is there a way by which I can automatize the changing of equations in maestro setup depending on the inputs and outputs? Also , depending in the inputs and outputs selected , I need to automatically make changes in the testbench.

For the moment I think using "skillbrigde" (skill functions using python) the generation of schematic can be done writing a code , but I dont understand how I can make the link with maestro testbench.

If you have any solutions , please let me know.

Thank you.

Specify reference verilog file returns NONE in hierarchy editor for grouped cells

ArthurP — Tue, 21 Jul 2026 08:11:22 GMT

Hello,

To give some context I want to run Mixed Signal simulator with AMS and I run Cadence 20.1.
After setting up the simulator, I have to replace the schematic views that we usually use in our analog flow in the Hierarchy Editor by their verilog model: the cells only contains schematic, layout, and symbol views and that cannot be changed.

Because of a different design methodologies among designers we have two standard cell types: with and without power pins. They both have the same model core. Every verilog modules are listed in a two .v files given by the founder with lib_pwr.v models for cells with power pins and lib.v models for cells without power pins.

I can easily replace the first cell type by their verilog models by precompiling lib.v verilog file, setting up "View found" as "Symbol", and changing "View list" so that "verilog" appears first. The simulation runs.

For the second type of standard cells, I first select relevant cells, use "Set Cell View", "Specify Reference Verilog" and select lib_pwr.v file in the interface. This also runs.

However, for grouped cells in the schematic with Ix<N:0> syntax, the Hierarchy Editor reports **NONE**: "This cell is explicitly bound to the 'module' view. The 'module' view does not exist for this cell" and path to .v file does not appear. The simulation cannot be launched.

It is possible to set them one by one in "Tree view" and run the simulation properly, but I cannot practically do this as there are hundreds of cells.

Note that both cells type could be linked to their verilog models using "Specify Reference Verilog".

Questions arise:

Verilog reference file works fine with single cells but not with grouped cells, is this normal behavior ? Is their any known workaround ?
Can the config file be exported, manually modified and imported ? "Save as verilog" returns an empty file.

Thanks,

Arthur

Export measurement units with axlExportOutputView() (ADE Maestro Results/Monte Carlo)

Johanny Saenz — Thu, 16 Jul 2026 11:13:38 GMT

Hello,

I am using the following SKILL commands to export ADE Maestro Monte Carlo results to CSV:

sess = axlGetWindowSession()

csvFilePath = "BANDGAP_MC_Export.csv"

axlExportOutputView(sess csvFilePath "Results" ?history "MC")

This successfully exports the numerical results, and the same approach also works for other output views (e.g., Summary, Yield, etc.).

However, I have not found a way to export the measurement units associated with each output. For example, I would like to obtain a column containing units such as:

or any other unit defined for the measurement.

I searched the SKILL documentation and experimented with axlExportOutputView(), but I could not find any option that exports the units together with the results.

My questions are:

Is there an option in axlExportOutputView() to include the measurement units in the generated CSV?
If not, is there another SKILL API that allows retrieving the units for each output expression programmatically?
Are the units stored in the Maestro session database and accessible through another object or function?

For reference, I am using Virtuoso ADE Maestro with Spectre (ICADVM 20.1 ISR75).

The motivation is to generate automated reports from the exported CSV files, where each measurement includes its corresponding engineering unit.

Any suggestions would be greatly appreciated.

Thank you.

preview for analogLib sources without running a simulation,

dogman4 — Fri, 10 Jul 2026 09:10:52 GMT

Hi，friends

What methods are there to preview analogLib sources without running a simulation?

My virtuoso version: "@(#)$CDS: virtuoso version 6.1.8-64b 09/03/2024 19:11 (sjfhw316) $"
My spectre version: Version19.1.0.063 64bit--10 Aug 2019

How to run an interactive external script from SKILL?

LoVyacheslavvVEMs — Wed, 01 Jul 2026 11:57:53 GMT

Hi,

I need to launch an external script from SKILL. The script itself is not under my control - it may be a shell script, Python script, executable, or any other program.

The important part is that the script may pause at arbitrary points and wait for user input from stdin. When this happens, I would like to prompt the user in Virtuoso (for example, using an AppForm), send the entered text back to the running process, and then continue its execution.

I know about system() and ipcBeginProcess(), but I'm not sure whether SKILL supports this kind of interactive communication with a child process.

Is there a supported way to:

launch an external interactive process from SKILL;
detect when it is waiting for input;
send user input back to the process while it is running?

Thanks in advance.

maeGroupAsParametricSet has no ?session argument

SK202511261716 — Wed, 01 Jul 2026 09:12:35 GMT

I have a SKILL script running inside a form which at one point needs to create a parametric set for the Design Variables of a particular Test. I'm using maeGroupAsParametricSet for this, and it's worked well so far. Unfortunately I've just run into a problem: if I have multiple maestro windows open, maeGroupAsParametricSet starts to misbehave. Unlike other mae functions, it can't be provided a ?session argument. So if I run my form from the second maestro view that I've opened, it will fail to find the Test I specify, because it's looking for it in the first maestro view. I tested this with maeGetTestSession: if I don't provide the ?session argument, it returns nil, whereas if I do provide it, it runs successfully. This suggests to me that maeGroupAsParametricSet is looking in the first view by "default", and lacking a ?session argument it can't be told to look elsewhere. Am I misunderstanding something here, or is there a workaround for this?

The warning message that appears after calling maeGroupAsParametricSet reads as follows:

WARNING (ASSEMBLER-1602): Cannot find test <TESTNAME> in the setup database. The test name passed to this function does not exist in the setup database. Perhaps the name was misspelled or has not yet been created. The test needs to be created before calling this function.

I'm on version IC23.1-64b

Prevent Net Extraction for Shapes

PK202501238151 — Wed, 17 Jun 2026 07:44:07 GMT

Hi,

is there a way to prevent net extraction for specific shapes? I'm generating layouts with external tools and mark the with `lxStickyNet = t` to prevent their nets to change by the extraction. However, there are also shapes that have no net assigned, and they change connectivity, even though lxStickyNet is set.

Thanks, kind regards,

Patrick

Is there any callback feature for layout that triggers any property change for instance?

MM20260514770 — Tue, 16 Jun 2026 20:20:09 GMT

Hi,

I am trying to port some in house script from TCL to skill for virtuoso. I am unable to find any callback code for layout that could perform following task.

For example, let's say I have an instance and a track region is fully covering it. Is there any callback that will trigger when that particular instance has any change of property for example origin change, or row/col number changed for mosaic?

In TCL there was a callback available which will pass the modified instance object and I can filter out if the cell name matches and then my fuction could extend/shrink or shift the track region so that it still fully covers the instance.

Thanks,

Tanvir

ipcSkillProcess and results buffering

BS202501273649 — Tue, 16 Jun 2026 11:45:05 GMT

I am using ipcSkillProcess to allow a Python program to send SKILL commands to Virtuoso and consume the results. It all works very well - I use read on the Python side and it gets back bytes containing the result of evaluating the command sent.

In production I generally haven't seen any problems but in theory it seems I should worry about the length of the results - the read could provide a buffer's worth but there might be more to come. The manual talks about a 4096 byte buffer but I've certainly got more than that in a single read. But I have been able to exceed some buffer size somewhere in a testing scenario by making the result of the evaluation very long. Then my Python program only gets the first part of the results truncated and the rest comes through in the next read. Not sure if that is a Python or a Virtuoso buffer size.

I could fix that by forcing some delimiters into the results and in Python reading until I get the terminating delimiter but that's a bit constraining on the results format. Or I could maybe check for the buffer being full somewhere (on the Python side or the Virtuoso side?) and giving an error or special casing it somehow.

Neither seem very attractive. Is there a sensible standard pattern for handling this?

Lock icon appears when SKILL PCell is loaded

thiruvenkata — Mon, 15 Jun 2026 12:59:40 GMT

Hi All,

I noticed something new while creating PCells using SKILL. Whenever I load the SKILL PCell, a user lock icon appears in the view type section. The only way I can get rid of it is by opening and closing the supermaster cellview.

I am currently using the pcCellView variable in my PCell development. Is there an internal variable or a proper method to automatically close the PCell cellview after it opens, creates the required geometries, and finishes processing?

I cannot attach screenshot for some reason, so I'll share the screenshot using image hosting:

github.com/.../1bc9ff6b-08f0-4875-bbd1-942fb96273bf

How to make the well proximity effect default to auto?

RM202605273230 — Fri, 12 Jun 2026 10:38:51 GMT

Hello

How to make the well proximity effect default to auto? i am currently using the tsmc 65nm where after placing the each transistor i have to go in symbol properties and make the well proximity option to auto instead i am looking for some option default all transistor can be make to auto in 1 go ?

thank you

ipcGetExitStatus() does not give correct return value

mbracht — Wed, 20 May 2026 15:09:44 GMT

I'am running a bash shell script as an ipc process...like this

(let (ipc)
ipc=(ipcBeginProcess "myScript.bsh 0")
ipcWait(ipc)
ipcGetExitStatus(ipc)
)

The bash script myScript.bsh is simple, it's return value is whatever I pass in as an argument

#!/bin/bash

exit $1

However I keep getting 127 from ipcGetExitStatus(..) - regardless from whatever the bash script actually returns.
Strangely it works for Unix built-in commands like for example "ls".

Any idea?

thanks
Max

Re-evaluate results in assembler via SKILL?

leok — Mon, 11 May 2026 16:02:11 GMT

Hi,

I might be blind, but I cannot find the SKILL function which does the same as clicking the "re-evaluate" button in the assembler results... Is there one?
It would be useful as I'm creating a report generator and want to ensure that I can see the latest results.

Best Regards,
leo

print pins into csv file

gangliurfic — Sat, 09 May 2026 06:17:12 GMT

I want to select an instance in a schematic and then call a function to save all the pins, name, direction, signal type, net into a csv file.

Is there such a build in function in Cadence?

I have a code working for name and direction, but got stuck at signal type

Below is the part of the code i am using, name and direction works fine, but signal type returns nil, so I am getting errors for fprint.

pinname=instTerm~>term->name
pindirection=instTerm~>term->direction
pinsig=instTerm~>term~>sigType
netname=instTerm~>term~>net~>name
fprintf(myPort "\n%s\t%s\t%s\t%s" pinname pindirection "not working yet" netname)

How can this be fixed?

Thanks!

Skill script to auto save upon streamout, and upon page up throughout layout hierarchy

blankman — Fri, 08 May 2026 16:58:23 GMT

Hi, Haven't had the time to look into creating this via Skill myself yet, just putting feelers out to see if anything already exists. Had a look through existing posts but coud not locate.

Just wondering if there is a possibility to autosave upon streamout within Virtuoso?

Also, is it possible to setup an auto save feature to auto save upon page up through layout hierarchy?

I am trying to minimize the amount of popups I see asking me if I want to save the cellview if layout edits have been made but not saved.

Any help very much appreciated,

Kr,

Brian.

how to make the variables and utilize the coordinates.

Noobnoob — Mon, 04 May 2026 04:50:48 GMT

Hello, i'm sorry for my english skill.

As a title, i wonder how to make variables and count those.

I'm making Layout Skill that count Channel of MOS by using skill language.

For example,

if two MOS that have w = 5um & l = 5um and two MOS that have w = 3um & l = 5um are placed in top level Layout Cellview.

I want to show that number of each MOS that include channel size in CIW.

CIW :

width = 5um & length = 5um, multi = 2ea

width = 3um & length = 5um, multi = 2ea

Presently, i got coordinate of each channel in top level.

But, i have trouble with utilzing coordinates...

How can i make variables by size and count those....?

below, i made a script by using skill language and wonder how to utilize coordinates.