ng

Create bounding shape for arcs

When using Shape > Create Bounding Shape on an arc, the outer side works well, but on the inner side it just draws a straight line from the begging to the end of the curve.  Is anyone aware of a fix for this?

I'm attaching  a picture as an example, it works great on lines.




ng

No windows cascading in OrCAD Capture 17.4

Hello All,

I'm a novice to this forum and probably this subject has been already discussed here.

My company has purchased OrCAD Capture 17.4 tools that have a new GUI if compared to my earlier used OrCAD Capture 9.2. I have been using Capture 9.2 for ~18 years and its GUI is really convenient. The GUI of 17.4 looks to be a modern one with new icons and really has improved features and new capabilities.

However, my main complain about GUI 17.4 is that the schematic windows cannot be cascaded. Although they can be set floating, this is even more annoying because all toolbars remain in the Capture window and when you select a tool, the Capture window pops over already open schematic window and you need a lot of useless extra clicks to return back to the currently edited schematic page. I always used cascading of schematic windows before because my complex designs includes many pages, not speaking about the library windows that are typically open simulatneously. My view is that the lack of CASCADING in Capture GUI 17.4 is critical and unacceptable for complex projects, and I would very highly appreciate if the Cadence guys will return back the CASCADING capability for schematic pages. In case this will be done, this will make the GUI really great and comfortable to use.

Does anybody have opinion on this issue?

Many thanks,

Pavel




ng

Sense line and decoupling capacitors

Hello,

A mybe silly question came to my mind: When routing sense lines, is it better to hav them as close as possible to DUT or afer the decoupling capacitors ?

Force in red, sense in purple.

Best way is 1 or 2 ?

Thanks in advance and Merry Christmas to everybody !




ng

Netlisting error when doing parametric sweep on transient simulation

Dear all,

I defined two design variables in ADE Assembler, say V1 and V2, that define the voltage 1 and voltage 2 of a "vpulse" voltage source in my schematic.

Then, I define V1 = 1.0, and V2 = 2.0, run a transient simulation, and everything is as expexcted. The source provides pulses between 1.0 V and 2.0 V.

Next, I set V1 = 1.0:0.5:1.5, thereby creating a parametric sweep with 1.0 V and 1.5 V for V1. I keep V2 at 2.0 V. Then the simulation fails, and all I get is "netl err" in my Output Expressions and an error message that the results directory does not exist and nothing can be plotted: This is reasonable, as the results directory is deleted on starting a new simulation, and as there is no simulation result, none of my output expressions can be plotted.

WARNING (OCN-6040): The specified directory does not exist, or the directory does not contain valid PSF results.
        Ensure that the path to the directory is correct and the directory has a logFile and PSF result files.
WARNING (ADE-1065): No simulation results are available.
ERROR (WIA-1175): Cannot plot waveform signals because no waveform data is available for plotting.
One of the possible reasons can be that 'Save' check box for these signals are not selected in the Outputs Setup pane. Ensure that these check boxes are selected before you run the simulation.

Normally, this kind of para,metric sweep is not a problem, I have done this many times before. There must be something special in THIS PARTICULAR test bench or simulator setup. The trouble is, I don't get any useful error messages.

Does anyone know what might be the problem here OR where to find useful information to investigate further (log files stored somewhere)? Thank you!

Regards,

Volker

P.S. Using Corners instead does not help either. Running it through all values by hand works, though.




ng

Cannot access individual noise contributions using SpectreMDL

I have tried replicating the setup described in a previous post (here), with the proposed solution.

 

The MDL measurements return a value of 0 for all exported result but the first.

Using Viva I can actually see the correct value for each contribution.

I am using :
- Spectre 23.1.0.538.isr10
- Viva IC23.1-64b.ISR8.40

What should I do differently?

Thanks!

***** test.scs *****
r1 (1 0) res_model l=10e-6 w=2e-6
r2 (2 1) res_model l=15e-6 w=2e-6
vr (2 0) vsource dc=1.0 mag=1
model res_model resistor rsh=100 kf=1e-20*exp(dkf)
parameters dkf=0
statistics {
  process {
    vary dkf dist=gauss std=0.5
  }
}

noi (1 0) noise freq=1

/***** test.mdl *****/
alias measurement noi_test {
  run noi;
  export real noi_total=noi_test:out;
  export real r1_total=r1:total;
  export real r1_flicker=r1:fn;
  export real r1_thermal=r1:rn;
  export real r2_total=r2:total;
  export real r2_flicker=r2:fn;
  export real r2_thermal=r2:rn;
}

run noi_test

**** test.measure ****

Measurement Name   :  noi_test
Analysis Type      :  noise
noi_total             =  6.9282e-06
r1_flicker            =  0
r1_thermal            =  0
r1_total              =  0
r2_flicker            =  0
r2_thermal            =  0
r2_total              =  0




ng

Error using probe terminal for dspf stb analysis

IC 23.1-64b.ISR8.40

Hi all, I'm trying to run an stb analysis in a dspf extracted view via Probe terminal. The instance exist in the dspf and I already prepended the X that is placed in the dspf extraction.

Spectre complains with the following error:

Error found by spectre during STB analysis `stb'.
    ERROR (SPECTRE-16408): The probe parameter must be specified to perform stability analysis.

Analysis `stb' was terminated prematurely due to an error.

What is missing here?




ng

Change code in veriloga view from external program

For reasons too complicated to go into here, I need to generate the code for a veriloga view from a outside the normal Verilog-A editor. I would start with an "empty" veriloga view generated from the symbol in the normal way so I get the port order correct, then use external code to provide "guts" of the veriloga view by overwriting the generated code.

My understanding is that and code changes made external to the normal flow do not get picked up by Cadence - the Verilog-A code gets read at design time, not at netlist time. Would simply forcing a check and save of the veriloga view after the code is modified fix that problem? Or is there an easier way to incorporate externally generated Verilog-A code?




ng

Verilog-A: Can I ignore WARNING (VACOMP-1047)

I need to include Verilog-A files which live outside the Cadence ecosystem (i.e., they are not in veriloga views but rather are just text files) into a veriloga view. These external modules are not compatible with OA (parametized port widths) so I can't put them into cellviews and hook them together using schematics.

Example: I have a cellview "test" which has a symbol and veriloga view. I have three "externaI" modules mod1 (inside an external file mod1.va),  mod2 (inside an external file mod2.va),  and mod3 (inside an external file mod3.va). I instantiate one instance of each module in "module test". The three modules have some parametized ports which are interconnected by parameterized signals p1 and p2. These two signals are strictly local to the module.

At the bottom of the module I use "`include mod1.va", "`mod2.va", etc.

When I check and save test->veriloga it checks all the included modules as well as the "test" module. However, I get a warning:

Warning from spectre during AHDL compile.
WARNING (VACOMP-1047): The Verilog-A file contains more than one module
definition. ADE can process only one module per Verilog-A file. Put
only one module in each Verilog-A file so that ADE can identify pin
names, directions, and hierarchy within each separate module.

Is this just a SUGGESTION that I can safely ignore, or are my included modules going to be ignored?




ng

Xcelium/Simvision/xrun running very slow (waiting for SimVision/Verisium Debug to connect...)

Hello,


I would like to use the simulation software xrun/simvision that comes with XCELIUM. We are currently using classroom licenses and want to disable all ip addresses on the student pcs except the license server ip. We want to make sure that students cannot copy confidential data from the Cadence tools.


Problem:

When I launch the xrun simulation while all ip addresses are blocked, it starts but the performance is very slow. The GUI starts after 5 minutes and the simulation is ready after 10 minutes. The interesting thing is that when I enable all blocked ip addresses, everything works at a reasonable speed.

Terminal Output (execution without internet connection):

xrun -gui design.vhd

waiting for SimVision/Verisium Debug to connect...


Is there a way to run the simulation tools without an Internet connection? Or can you give me the ip addresses that are used by the simulation tools so that I can enable only those specific ips?


Regards,

Max




ng

Characterization of Full adder that use transmission gates using liberate

Hello,
I'm trying to characterize a full adder that use transmission gate.
Unfortunately, the power calculation are wrong for the cell are always negative.
Is there any method or commands that can can help in power calculation or add the power consumption by the input pins to the power calculation ?
Another question, Is liberate support the characterization or transmission gate cells as standard cells or I should use liberate AMS for these type of cells ?
Thanks in advance,
Tareq 




ng

error when generating snp files from a variable

Hello everyone, 
I have a testbench for generating s2p files from a SP simulation that was working until few months ago. Today I have reopened (w/o making changes that I am aware of) and I get the error as shown below:

first I show the testbench settings:

notice how the s2p generation is disabled: the field "file" is left blank

in the corner I defined some parameters, "filename" is the word that is suppose to generate the name for the s2p. 

where the two variables are defined as follows

And now the output log:

spectre.out file gives the following error:


When clicking on the error message at "9", the input.scs file opens up and the line 9 gets highlighted in green



now, so far I understood that the problem seem to be related tom the "pathcds" variable, but I really don't understand what the error message here means, since I don't see any error in the input.scs file

by the way - if for instance I define the variable "filename" as shown below, then I get no errors:


thanks
Tommaso




ng

Colorcoding for low cpk in Yield-View in Assembler

Hi,

I'm searching for a way to get a quick overview of too low cpk-values after a montecarlo sim. The non-MC results have the spec and thus the easy/understandable red/green/(yellow) colorcoding, but for MC sims I don't get a highlight for high variations inside the limits.

Is this possible (besides copying each expression into avg()+3*std()) and ..-..)?

It would be really handy to scan through finished sims...

(My final application is then to export the table for my reports and documentation...)

Regards,

leo




ng

Force virtuoso (Layout XL) to NOT create warning markers in design

Hi

I have a rather strange question - is there a way to tell layout XL to NOT place the error/warning markers on a design when I open a cell?  I do a lot of my layout by using arrays from placed instances and create mosaics that completely ignore the metadata that Layout XL uses with its bindings with schematic (and instances get deleted etc. but I do like using it to generate all my pins etc.) and it's just really annoying when I open a design that I know is LVS clean and since the connectivity metadata is all screwed up (because I did not use it to actually complete the layout) I have a design that's just blinking at me at every gate, source and drain.  I typically delete them at the high level heirarchically but the second I go in and modify something and come back up it places all of them again.  I know that if I flatten all the p cells it goes away but sometimes it's nice to have that piece of metadata but that's about it.  Is there a way to "break" the features of XL like this?  I realize what a weird question this is but it's becoming more of an issue since we moved to IC 23 from IC 6 where there is no longer a layout L that I can use free from these annoyances that can't use any of the connectivity metadata.

Thanks

Chris




ng

Tagging uvm_errors in waveform file for post-processing

Hi,

Do anyone know if it's possible in simvision waveform viewer to see a timestamp of where uvm_errors/$errors occurred in a simulation via post-processing? 

Cheers,

Antonio




ng

Using Xcelium, xrun -nogui option, where are the simulation results

I'm completely new to Cadence. I've been able to run a very simple simulation with the -gui option. Simvision opens, I add the variables to the waveform viewer, and press run. All is good.

I don't understand the flow when using the -nogui option. It appears that the simulation runs and returns control to the OS. When I launch Simvision, is there a database or file that I can open to display the already-simulated data?

My command is of the form:

xrun -gui -64bit -sv -access +rwc -top tb_top.sv <src files>




ng

Importing ODF to vManager does not update vplan

I exported vplan to .odf file in vManager and after editing it I imported it to vManager. The vplan was expected to be synchronized and updated. However, nothing has changed to it. Does anyone know why?




ng

UVM debugging: How to save and load signals during an interactive session in Simvision

Hello,

I am aware of command script .svcf file that saves signals and loads them in while opening Simvision.

I am wondering, if there is a way for saving signals while we are in an interactive session and loading them next time when we open Simvision interactively.

Any ideas on how to do this?

Thank you in advance.

Swetha. C




ng

Using Vmanager Pre-Script to launch a timed script

I would like to send an update about a vmanager regression status x days after the regression has been run. In the current environment, the vmanager regression is creating a new filepath for logs automatically based on regression name/date, so I can't use a cron job to gather logs, as the log location is not known. 


I tried to use the pre session script to launch a detached shell script that would run after a delay, but when the pre_script runs, it waits until everything is completed before finishing and moving on to starting the regression.

Here is the test pre_script I am using:

#!/bin/sh

echo "pre_script start"

delay_script "FIRST" 1
nohup delay_script "SECOND" 30 & disown
delay_script "THIRD" 1

echo "pre_script end"
exit 0

Here is the test delay_script I am using:

#!/bin/sh

echo "Starting $1"

sleep $2

echo "Ending $1"

Here is the script output when run from terminal. After the "pre_script end", I get control back.

Here is the script output when run from vmanager. There is no "nohup", and the pre_session phase doesn't complete until all the delay scripts complete.


My question is, is there a better way to achieve my goal here? (The goal being to run a script from the vmanager log directory automatically x days after the regression). I think I could use the pre_script to send directory information for an auxiliary cron job to pick up, but I would prefer to not have to have extra cronjobs needed for this.




ng

vManager crashes when analyzing multiple sessions simultaneously with a fatal error detected by the Java Runtime Environment

When analyzing multiple sessions simultaneously Verisium Manager crashed and reported below error messages:

# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007efc52861b74, pid=14182, tid=18380
#
# JRE version: OpenJDK Runtime Environment Temurin-17.0.3+7 (17.0.3+7) (build 17.0.3+7)
# Java VM: OpenJDK 64-Bit Server VM Temurin-17.0.3+7 (17.0.3+7, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# C  [libucis.so+0x238b74]

......

For more details please refer to the attached log file "hs_err_pid21143.log".

Two approaches were tried to solve this problem but neither has worked.
Method.1:

Setting larger heap size of Java process by "-memlimit" options.For example "vmanager -memlimit 8G".

Method.2:

Enlarging stack memory size limit of the Coverage engine by setting "IMC_NATIVE_STACKSIZE" environment variable to a larger value. For example "setenv IMC_NATIVE_STACKSIZE 1024000"

According to "hs_err_pid*.log" it is almost certain that the memory overflow triggered Java's CrashOnOutOfMemoryError and caused Verisium Manager to crash. There are some arguments about memory management of Java like "Xms, Xmx, ThreadStackSize, Xss5048k etc" and maybe this problem can be fixed by setting these arguments during analysis. However, how exactly does Verisium Manager specify these arguments during analysis? I tried to set them by the form of setting environment variables before analysis but it didn't work in analysis and their values didn't change.

Is there something wrong with my operation or is there a better solution?

Thank you very much.




ng

explain/correct my understanding between average/covered in imc metrics

I'm working on the code coverage. Doing a metrics analysis by default we see overall average grade and overall covered. But when i do a block analysis on an instance i see overall covered grade, code covered grade, block covered grade, statement covered grade, expression covered grade, toggle covered grade.

As I dont know the difference I started to read the IMC user guide and came to know there are 3 things we come across while doing a code coverage local, covered, average

From my understanding

local - child instances metrics doesnt reach the parent level. For example, we have an instance Q and its sub instances like Q.a, Q.b. Block Local grade of Q can be 100% even when its instances Q.a and Q.b a block local grades isnt at 100%.

In the attached image there is formula 

The key difference between average and covered is the weights.

Average : Mathematically taking the above scenario where Q.a, and Q.b has 10 blocks each. Q.a has covered 8 blocks and q.b has covered 2 blocks. Now if we take the normal average it should be total covered/ totatl number = 8+2/10+10 yielding 50%. But when we add weights saying Q.a is 70% and Q.b is 30% the new number would be (8*0.7+2*0.3) / (10*0.7+10*0.3) resulting 62%. Because of the weights we see 12% bump.

Covered: there is no role of weights.

Among these 3 metrics i've changed my default view to this in the image to get more realistic picture when i do analyze metrics. Do you guys agree with the approach?




ng

Parameterizing an Instance

Hi,
I want to parameterized width and length of a NMOS, but it ignore it and I face this error:
*WARNING* Value input must be a number - setting back to previous value.

Does anybody know how I can fix this issue?
Thanks




ng

Simvision Array Slicing

> reg [63:0] rMem [0:255] signal

it can be confirmed by rMem [0:255] in Simvision

Is it possible to generate a new rMem1 signal and rMem2 signal by splitting it into 32 bits width through right-click> Create on rMem?




ng

Collecting Coverage using Vmanager

Hi, 

I am running a regression in order to collect the coverage. However I have an issue. I am setting a signal to 0 when reset is de-asserted  then this signal takes a fixed value when the reset is asserted. 

if(!rst_n) 
init_val= 'b0;

else 

init_val31'h34013FF7

the issue is that I got 0%  coverage for the init_value since we only have a rising edge and the signal is not toggling during the simulation. is there an option to collect coverage when there is a rising edge or a falling edge? 




ng

Using vManager to identify line coverage from a specific test

I have been using the rank feature to identify tests that are redundant in our environment, but then I realized I'd also like to be able to see exactly what coverage goes into increasing the delta_cov value for a given test. If I had a test in my rank report that contributed 0.5% of the delta_cov, how could I got about seeing exactly where that 0.5% was coming from? It seems like that might be part of the correlate function, but I couldn't mange to find a way to see what specific coverage was being contributed for a given test.




ng

Auto-Coloring Waves in Simvision?

Hello,

First, I had something working that broke in the past few versions that I've been meaning to get working again. There was some setting I recall in the GUI that allowed me to have inputs be placed in the waveform viewer with yellow traces, and output signals with orange traces to match the name colors. How can I set this to happen in the .simvisionrc file?

Second, I would like to add something to my .simvisionrc file to go through foreach signal and depending on key locations based on the signal's Path.Name (mainly the model and design areas) such that if the path contains "mon", then to auto-set the trace and name colors to something such as cyan. I'd like to have loops for various key areas of the design to color-code the signals.

Third, I am interested if there is a possibility of coloring names/traces foregound colors to based on which position they are in the waveform viewer to make banding, ideally such that every three (or whatever) are one color (or a color mutation, adding some gray to signals colorized by the auto-coloring mentioned already, etc) that allows for the signal names/traces to be colorized along with the built-in optional black/gray background banding.

Thanks in advance




ng

Using "add net constraints" command in Conformal

Hi

I have tried using "add net constraints" command to place one-cold constraints on a tristate enable bus. In the command line we need to specify the "net pathname" on which the constraints are to be enforced.

The bus here is 20-bit. How should the net pathname be specified to make this 20-bit bus signals one_hot or one_cold.

The bus was declared as follows:
ten_bus [19:0]

The command I used was

add net constraints one_hot /ren_bus[19]

What would the above command mean?
Should we not specify all the nets' pathnames on the bus?
Is it sufficient to specify the pathname of one net on the bus?
I could not get much info regarding the functionality of this command. I would be obliged if anyone can throw some light.

Thanks
Prasad.


Originally posted in cdnusers.org by anssprasad




ng

Posting code to the forum

When posting code to the forums, copy from a text editor such as notepad, not from word or Outlook. Be sure to click the HTML tab BEFORE you paste your text.

Click on the "html" mode tab on your "reply" dialog box. Then wrap your text with like this:

pasted text

NOTE: Do not put a space in the I have done that here so it will show up as text. Also, be sure to click the HTML tab BEFORE you paste your text. This is how it will look when coded correctly pasted text


Originally posted in cdnusers.org by Administrator




ng

ce_tools directory no longer shipped with Specman

Hello All,

starting with version 8.1 the contents of the ce_tools directory will no longer
be shipped with Specman. The directory contains some unsupported AE/R&D
ware and has not been updated for several releases (i.e. most of those old
packages don't work with the latest release).
 
Attached is the contents of this directory. Please read the README before
using any of the packages.


Regards,
-hannes


Originally posted in cdnusers.org by hannes




ng

Simvision - Signal loading

Hi all 

Good day.

Can anyone tell me whether it is possible to view the signals once it is modified from its previous values without closing the simvision window. If possible kindly let me know the command for it(Linux).

 Is it possible to view the schematic for the code written?? Kindly instruct me.

 Thanks all.

S K S 




ng

help with automating adding CLP files to DRA files

Question for forum:
I’m currently working on a code to automatically add CLP files to DRA files and then add two classes called “APPROVED” and “CLP”. To do this manually you have to open a DRA file, click file import subdrawing and choose the clp file with the same name as dra. (path already set). You then set the clp to position x 0 0. And then click on Set Up > Subclasses > Package geometry and type in “Approved” and “Clp.”
So far we’ve recorded the macros in Allegro for all of these actions. The macros correspond to one specific file name and we want to apply this to numerous files. To do this we created a python program that locates all of the specified CLP and DRA files, and if they have a matching name, runs a for loop that puts each file name into a stored variable that runs a loop for each file. We converted this script into batch and then added a function that we thought would run Allegro macros from batch.
In order to get the script working, we need to have an allegro batch command that will run the script without opening the Allegro start popup, or closing the popup when it appears.  We need to do this to run any script from starting Allegro.
I’ve done another similar program in batch where I made a for loop for each dra file and within the loop there was a batch a2dxf command that converted all dra files to dxf files. Is there a similar batch command for adding clp files to position 0 0 and/ or adding classes? If anyone has done something similar please let me know!
Thank you very much for the help.
Jen




ng

Creating cover items for sparse values/queue or define in specman

Hello,

I have a question I want to create a cover that consists a sparse values, pre-computed (a list or define) for example l = {1; 4; 7; 9; 2048; 700} I'd like to cover that data a (uint(bits:16)) had those values, Any suggestion on how to achieve this, I'd prefer to stay away from macros, and avoid to write a lot of code

struct inst {

  data :uint(bits:16);
  opcode :uint(bits:16);
  !valid_data : list of uint(bits:16) = {0; 12; 10; 700; 890; 293;};
  event data_e;
  event opcode_e;

  cover data_e is {
     item data using radix = HEX, ranges = {
     //I dont want to write all of this
     range([0], "My range1");
     range([10], "My range2");
     //... many values in between
    range([700], "My rangen");
    };


    item opcode;


   cross data, opcode;
};

post_generate() is also {
    emit data_e;
};
};




ng

Overcoming Thermal Challenges in Modern Electronic Design

Melika Roshandell talks with David Malinak in a Microwaves & RF QuickChat video about the thermal challenges in today’s complex electronic designs and how the Celsius solver uniquely addresses them.(read more)





ng

BoardSurfers: Managing Silkscreen Data Using Allegro 3D Canvas

The silkscreen layer plays a crucial role in the assembly, repair, and testing of a PCB. You can add a variety of information to this layer, such as the location of the components, polarity, component orientation, on-off switches, LEDs, and testpoint...(read more)




ng

Quickchat Video Interview: Introducing Cadence Optimality and OnCloud for Systems Analysis and Signoff

Microwaves & RF's David Maliniak interviews Sherry Hess of Cadence about recently announced products of Optimality and OnCloud.(read more)




ng

BoardSurfers: Managing Design Constraints Efficiently Using Constraint Sets

A constraint is a user-defined property, or a rule, applied to a physical object, such as a net, pin, or via in a design. There are a number of constraints that can be applied to an object based on its type and behavior. For example, you can define t...(read more)




ng

BoardSurfers: Training Insights: What’s New in the Allegro PCB Editor Basic Techniques Course

The Allegro PCB Editor Basic Techniques course provides all the essential training required to start working with Allegro® PCB Editor. The course covers all the design tasks, including padstack and symbol creation, logic import, constraints setup...(read more)




ng

EMX - Localised back etching

Do you know if it is possible to define localized back etching (LBE) in EMX? It should be associated to a layer which defines the holes done in the substrate. I've not found any reference for this in the .proc syntax. 

--> Answer found. This is not possible because EMX considers the same dielectric in all x-y plane




ng

Error with launching Python Script Via AWRDE VBA Script

Hello Team,
I am currently following this AWR script posted on them, to run a python script directly from inside AWR using VBA script.

Launching Python from AWRDE VBA Script - AWR Scripts - AWR Knowledgebase

Following all the basic steps with no changes to the code. I have Vscode and python-3.12.2 installed in my system. 

This is the error I am getting while running this code. 

 

Thank you for your help 

Best Regards

SID




ng

Strmount failed in streaming out cell

Hi, I would be grateful if you can help me with this error which I get after trying to run an EMX simulation on a PCELL.

I've found very limited information in this forum. Thanks




ng

Error when trying to generate SUL license (-8)

Hi, newbie here.

We are using AWR Design Enviroment in our university and so I have to install it (OS: Arch Linux)
I installed it in a Windows 10 VM without problems.

When I try to start it prompts "Failed to connect to license server", I guess thats the first problem.

After that when trying to generate my SUL License it will prompt Internal Error -8 (see Image)

I can't find something on Error -8 :/ and overall the available data to the license topic is quit low :/

If someone has a solution for that I would gladly hear about it :)




ng

Measuring DDJ (data dependent jitter). Cross function on eye-diagram

Hi,
My Virtuoso and Spectre Version: ICADVM20.1-64b.NYISR30.2
I plot an eye diagram using a built in function. I want to see the data-dependent jitter. I want to measure the eye diagram edges at zero crossing (width of that diamond part) shown in the pic by vertical and horizontal markers. I can put a marker and read the numbers there and get what I want. But now I want to run Monte Carlo and I can't do this for all samples. I wish I could write an expression for this. Unfortunately, I see that the function "cross" is not working on the eye diagram. Basically, when I send the eye diagram data to a table, I see that it actually is just the prbs data and not the eye diagram data. Is there a hack that can help me achieve my goal which is: having an expression to measure the edges of the eye diagram at zero crossing?
There is a script that Andrew wrote (https://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin%3AViewSolution%3BsolutionNumber%3D11395772). This is a good script but it puts all edges on top of each other. I want to distinguish the two edges. In the attached pic (two-period eye diagram) you can see what I mean by the two edges (diamond shapes). I want to measure each of the two and take the maximum. Having all the edges on top of each other won't give me what I want. All edges together will lso include DCD. I purely want to measure DDJ. DCD is measured separately. I have very little experience with writing scripts and could not modify Andrew's script.
Your help is much appreciated. Thank you.




ng

PSS Shooting - High Q crystal oscillator - Simulator by mistake detects a frequency divider

Hi *,

 

I am simulating a 32kHz high Q crystal oscillator with a pulse shaping circuit. I set up a PSS analysis using the Shooting Newton engine. I set a beat frequency of 32k and used the crystal output and ground as reference nodes. After the initial transient the amplitude growth was already pretty much settled such that the shooting iterations could continue the job.

 

My problem is: In 5...10% of my PVT runs the simulator detects a frequency divider in the initial transient simulation. The output log says:

 

Frequency divided by 3 at node <xxx>

The Estimated oscillating frequency from Tstab Tran is = 11.0193 kHz .

 

However, the mentioned node is only part of the control logic and is always constant (but it has some ripples and glitches which are all less than 30uV). These glitches spoil my fundamental frequency (11kHz instead of 32kHz). Sometimes the simulator detects a frequency division by 2 or 3 and the mentioned node <xxx> is different depending on PVT - but the node is always a genuine high or low signal inside my control logic.

 

How can I tell the simulator that there is no frequency divider and it should only observe the given node pair in the PSS analysis setup to estimate the fundamental frequency? I have tried the following workarounds but none of them worked reliably:

 

- extended/reduced the initial transient simulation time

- decreased accuracy

- preset override with Euler integration method for the initial transient to damp glitches

- tried different initial conditions

- specified various oscillator nodes in the analysis setup form

By the way, I am using Spectre X (version 21.1.0.389.ISR8) with CX accuracy.

 

Thanks for your support and best regards

Stephan




ng

Getting error while adding element in AWR software

While adding an element created from a netlist file in AWR, I am getting the error 'The element type being dropped is not compatible with the window it is being dropped into'. The netlist file in AWR has the following contents:

.subckt BFG520W base collector emitter npn
.model BFG520W NPN(IS=1.016E-15 NF=1.000 BF=220.1 IKF=510E-3 VAF=48.06
+ ISE=2.83E-13 NE=2.035 NR=0.988 BR=100.7 IKR=2.352E-3
+ VAR=1.692 ISC=24.48E-18 NC=1.022 RB=10.00 RE=0.7753
+ RC=2.21 CJC=447.6E-15 MJC=0.07 VJC=0.1892
+ CJE=1.245E-12 TF=8.616E-12 TR=5.437E-12 mfg=NXP)

I have attached screenshots of the element BFG520W2 created due to the above netlist and the error I am getting while adding this element.


 




ng

Figures missing in the RF Design Blogs article of "Measuring Fmax for MOS Transistors"

Hi I noticed that some figures from the old posts in the cadence blogs have been missing.

I think this problem happened before and Andrew Beckett asked the original author to fix the issue:

 Figures missing in the RF Design Blogs article of "Measuring Fmax for MOS Transistors" 

Some of these posts are quite valuable, and would be nice to have access to the figures, which are a very important part of some posts,

Thanks

Leandro




ng

Virtuoso Meets Maxwell: Getting Your Existing SiP File Into Virtuoso RF Solution

I have been involved in the Virtuoso RF Solution for the last four years. Most of the customers I work with have a SiP package already in progress. They often ask "How do I get my SiP design into Virtuoso RF Solution?" I am excited about new functionality in the latest ICADVM20.1 ISR25 release. It is a new GUI under the Tools menu called Enablement. (read more)




ng

Start Your Engines: AMS Flex – Our Next Generation Architecture Matures

An AMS Designer Flex simulation gives you the most immediate access to the latest simulation technology on either side, gets out of the way of the core engines and allows the engine performance to shine while providing access to new features. Check out this blog to know more.

(read more)




ng

Knowledge Booster Training Bytes - What Is a Parameterized Cell and What Are the Advantages

Che(read more)



  • Relative Object Design
  • PCells
  • Virtuoso Video Diary
  • Custom IC Design
  • Virtuoso Layout Suite
  • SKILL

ng

Spectre Tech Tips: Introducing Spectre X EMIR Voltus-XFi

This blog describes the new capabilities in Spectre 21.1 ISR2 through which it provides support to the Voltus-XFi Custom Power Integrity Solution.(read more)



  • Spectre X EMIR
  • Voltus-Fi-XL
  • Virtuoso Analog Design Environment
  • Spectre X distributed simulation
  • Spectre X Simulator

ng

Start Your Engines: An Innovative and Efficient Approach to Debug Interface Elements with SimVision MS

This blog introduces you to an efficient way to debug interface elements or connect modules in a mixed-signal simulation.(read more)