Hi,

There was tool available with INCISIV called imc to view the coverage reports.

The question is: How can we view the code coverage reports generated with XCELIUM? I think imc is not available with XCELIUM?

Thanks in advance.

Hi,

Is it possible to use a SystemVerilog package which is compiled into a library and then use it in a VHDL-2008 design file? Is such mixed-language flow supported?

I'm considering the latest versions of Incisive / Xcelium available today (Oct 2019).

Thank you,

Michal

Here we conclude the blog series and highlight the results of Mediatek 's use of Cadence Perspec™ System Verifier for their SoC level verification. In case you missed it, Part 1 of the blog is here , and Part 2 of the blog is here . One of their key...(read more)

Those who work in the IC Packaging design space have some unique challenges. We bridge between the IC design world (90/45-degree traces with rectangular and octagonal pins) and the PCB domain...

[[ Click on the title to access the full blog on the Cadence Community site. ]]

Our customers’ tests have become more complex, longer, and consume more resources than before. This increases the need to optimize the regression while not compromising on coverage. Some advanced...

[[ Click on the title to access the full blog on the Cadence Community site. ]]

We have talked about aspects of the in-design symbol edit application mode in the past. This is the environment specific to the Allegro® Package Designer Plus layout tools allowing you to work...

[[ Click on the title to access the full blog on the Cadence Community site. ]]

In the former blog about Python and Specman: Specman: Python Is here!, we described the technical information around Specman-Python integration. Since Python provides so many easy to use existing libraries in various fields, it is very tempting to leverage these cool Python apps.

Coverage has always been the center of the verification methodology, however in the last few years it gets even more focus as people develop advanced utilities, usually using Machine Learning aids. Anyhow, any attempt to leverage your coverage usually starts with some analysis of the behavior and trends of some typical tests. Visualizing the data makes it easier to understand, analyze, and communicate. Fortunately, Python has many Visualization libraries.

In this blog, we show an example of how you can use the plotting Python library (matplotlib) to easily display coverage information during a run. In this blog, we use the Specman Coverage API to extract coverage data, and a Python module to display coverage grades interactively during a single run and the way to connect both.

Before we look at the example, if you have read the former blog about Specman and Python and were concerned about the fact that python3 is not supported, we are glad to update that in Specman 19.09, Python3 is now supported (in addition to Python2).

The Testcase
Let’s say I have a stable verification environment and I want to make it more efficient. For example: I want to check whether I can make the tests shorter while hardly harming the coverage. I am not sure exactly how to attack this task, so a good place to start is to visually analyze the behavior of the coverage on some typical test I chose. The first thing we need to do is to extract the coverage information of the interesting entities. This can be done using the old Coverage API. 

Coverage API
Coverage API is a simple interface to extract coverage information at a certain point. It is implemented through a predefined struct type named user_cover_struct. To use it, you need to do the following:

1. Define a child of user_cover_structusing like inheritance (my_cover_struct below).
2. Extend its relevant methods (in our example we extend only the end_group() method) and access the relevant members (you can read about the other available methods and members in cdnshelp).
3. Create an instance of the user_cover_structchild and call the predefined scan_cover() method whenever you want to query the data (even in every cycle). Calling this method will result in calling the methods you extended in step 2.  

 The code example below demonstrates these three steps. We chose to extend the end_group() method and we keep the group grade in some local variable. Note that we divide it by 100,000,000 to get a number between 0 to 1 since the grade in this API is an integer from 0 to 100,000,000. 

Pass the Data to a Python Module
After we have extracted the group grade, we need to pass the grade along with the cycle and the coverage group name (assuming there are a few) to a Python module. We will take a look at the Python module itself later. For now, we will first take a look at how to pass the information from the e code to Python. Note that in addition to passing the grade at certain points (addVal method), we need an initialization method (init_plot) with the number of cycles, so that the X axis can be drawn at the beginning, and end_plot() to mark interesting points on the plot at the end. But to begin with, let’s have empty methods on the Python side and make sure we can just call them from the e code.

 # plot_i.py
def init_plot(numCycles):
    print (numCycles)
def addVal(groupName,cycle,grade):
    print (groupName,cycle,grade)
def end_plot():
    print ("end_plot") 

And add the calls from e code:

 Before running this, note that you need to ensure that Specman finds the Python include and lib directories, and Python finds our Python module. To do this, you need to define a few environment variables: SPECMAN_PYTHON_INCLUDE_DIR, SPECMAN_PYTHON_LIB_DIR, and PYTHONPATH. 

 The Python Module to Draw the Plot
After we extracted the coverage information and ensured that we can pass it to a Python module, we need to display this data in the Python module. There are many code examples out there for drawing a graph with Python, especially with matplotlib. You can either accumulate the data and draw a graph at the end of the run or draw a graph interactively during the run itself- which is very useful especially for long runs.

Below is a code that draws the coverage grade of multiple groups interactively during the run and at the end of the run it prints circles around the maximum point and adds some text to it. I am new to Python so there might be better or simpler ways to do so, but it does the work. The cool thing is that there are so many examples to rely on that you can produce this kind of code very fast.

 In the example we used, we had two interesting entities: packet and state_machine, thus we had two equivalent coverage groups. When running our example connecting to the Python module, we get the following graph which is displayed interactively during the run.

When analyzing this specific example, we can see two things. First, packet gets to a high coverage quite fast and significant part of the run does not contribute to its coverage. On the other hand, something interesting happens relating to state_machine around cycle 700 which suddenly boosts its coverage. The next step would be to try to dump graphic information relating to other entities and see if something noticeable happens around cycle 700.

To run a complete example, you can download the files from: https://github.com/okirsh/Specman-Python/

Do you feel like analyzing the coverage behavior in your environment? We will be happy to hear about your outcomes and other usages of the Python interface.

Orit Kirshenberg
Specman team

Our customers’ tests have become more complex, longer, and consume more resources than before. This increases the need to optimize the regression while not compromising on coverage.

Some advanced customers of Specman use Machine Learning based solutions to optimize the regressions while some use simpler solutions. Based on a request of an advanced customer, we added a new Coverage API in Specman 19.09 called Coverage Callback. In 20.03, we have further enhanced this API by adding more options. Now there are two Coverage APIs that provide coverage information during the run (the old scan_cover API and this new Callback API). This blog presents these two APIs and compares between them while focusing on the newer one.

Before we get into the specifics of each API, let’s discuss what is common between these APIs and why we need them. Typically, people observe the coverage model after the test ends, and get to know the overall contribution of the test to the coverage. With these two APIs, you can observe the coverage model during the test, and hence, get more insight into the test progress.

Are you wondering about what you can do with this information? Let’s look at some examples.

1. Recognize cases when the test continues to run long after it already reached its coverage goal.
2. View the performance of the coverage curve. If a test is “stuck” at the same grade for a long time, this might indicate that the test is not very good and is just a waste of resource.

These analyses can be performed in the test itself, and then a test can decide to either stop the run, or change something in it configuration, or – post run. You can also present them visually for some analysis, as shown in the blog: Analyze Your Coverage with Python.

scan_cover API (or “Scanning the Coverage Model”)

With this API you can get the current status for any cover group or item you are interested in at any point in time during the test (by calling scan_cover()). It is very simple to use; however it has performance penalty. For getting the coverage grade of any cover group during the test, you should
1. Trigger the scan_cover at any time when you want the coverage model to be scanned.
2. Implement the scan_cover related methods, such as start_item() and end_bucket(). In these methods, you can query the current grade of group/item/bucket.
The blog mentioned earlier: Analyze Your Coverage with Python describes the details and provides an example.

Callback API

The Callback API enables you to get a callback for a desired cover group(s), whenever it is sampled. This API also provides various query methods for getting coverage related information such as what the current sampled value is. So, in essence, it is similar to scan_cover API, but as the phrase says: “same same but different”:

1. Callback API has almost no performance penalty while scan_cover API does.
2. Callback API contains a richer set of query methods that provide a lot of information about the current sampled value (vs just the grade with scan_cover).
3. Using scan_cover API, you decide when you want to query the coverage information (you call scan_cover), while with the Callback API you query the coverage information when the coverage is sampled (from do_callback). So, scan_cover gives you more flexibility, but you do need to find the right timing for this call.

There is no absolute advantage of either of these APIs, this only depends on what you want to do.  

Callback API details

The Callback API is based on a predefined struct called: cover_sampling_callback. In order to use this API, you need to:

1. Define a struct inheriting cover_sampling_callback (cover_cb_save_data below)
   1. Extend the predefined do_callback() method. This method is a hook being called whenever any of the cover groups that are registered to the cover_sampling_callback instance is being sampled.
   2. From do_callback() you can access coverage data by using queries such as: is_currently_per_type(), get_current_group_grade() and get_current_cover_group() (as in the example below) and many more such as: get_relevant_group_layers() and get_simple_cross_sampled_bucket_name().
2. Register the desired cover group(s) to this struct instance using the register() method.

Take a look at the following code:

// Define a coverage callback.
// Its behavior – print to screen the current grade.
struct cover_cb_save_data like cover_sampling_callback {
    do_callback() is only {
       // In this example, we care only about the per_type grade, and not per_instance
       if is_currently_per_type() {           
            var cur_grade : real = get_current_group_grade();
            sys.save_data (get_current_cover_group().get_name(), cur_grade);
        };//if
    };//do_callback()
};// cover_cb_send_data


extend sys {
    !cb : cover_cb_save_data;

   // Instantiate the coverage callback, and register to it two of my coverage groups
    run() is also {
       cb  = new  with {
        var gr1:=rf_manager.get_struct_by_name("packet").get_cover_group("packet_cover");
        .register(gr1);
        var gr2:=rf_manager.get_struct_by_name("sys").get_cover_group("mem_cover");
       .register(gr2);
       };//new  
    };//run()

  save_data(group_name : string, group_grade : real) is {
        //here you either print the values to the screen, update a graph you show or save to a db 
  };// save_data
};//sys

In the blog Analyze Your Coverage with Python mentioned above, we show an example of how you can use the scan_cover API to extract coverage information during the run, and then use the Specman-Python API to display the coverage interactively during the run (using plotting Python library - matplotlib). If you find this usage interesting and you want to use the same example, by the Callback API instead of the scan_cover API, you can download the full example from GIT from here: https://github.com/efratcdn/cover_callback.

Specman Team

In my previous blog, I talked about creating a footprint using an existing template in Allegro ECAD-MCAD Library Creator and explained how easily you can access an existing template and create a package from it by just clicking a button. In this blog...(read more)

Other tools allow a sanity check of placement density vs available board space.  There is an older post "Skill code to evaluate all components area (Accumulative Place bound area)"  (9 years ago) that has a couple of examples that no longer work or expired.

This would be useful to provide feedback to schismatic and project managers regarding the component density on the PCB and how it will affect the routing abilities.  Thermal considerations can be evaluated as well 

Has anyone attempted this or still being done externally in spread sheets?

I have a script to handle many polys in memory in allegro. 

But after the completion of the script, 

I run the axlPolyMemUse(), it reports (31922 0 0 55076 252482)

Seems too many polys are still in the memory，and they are not being used. 

So how to delete these polys from the memory? And reclaim the memory?

BTW. I have no skill dev license. So gc() function doesn't work. 

Thanks.

Hello,
I'm exploring VManager tool capabilities.

I launched a simulation with xrun, which terminates with a fatal error (`uvm_fatal actually).

Then I imported the flow session, through VManager -> Regression -> Collect Runs, linking the directory with ucm and ucd of just failed run.

VManager imports the test with following attributes:

Total Runs =1

#Passed =1

#Failed =0

What I'm missing here? It should be imported as failed test.

If I right click on flow name and choose Analyze All Runs, VManager brings me to Analysis tab and I can see only a PASSED tag in Runs subwindow.

Thank you for any help

Hello!

I have input signal like this  ->  input  wire [ADM_NUM-1:0][1:0] m_axi_ddr_rresp.

When i want to analyze coverage from IMC  this signal not covered!

Can i collect coverage for this signal?

I have a problem connected with my AXI4 coverage.

I enable coverage collection in AXI4 

      set_config_int("axi4_active_slave_agent_0.monitor.coverModel", "burst_started_enable", 1);
      set_config_int("axi4_active_slave_agent_0.monitor.coverModel", "coverageEnable", 1);

but i don't have a result.

I think the problem in Callback, but i try to connect all callback and i don't have positive result.

Can you help me?

Hi  all,

          I am getting this warning in while generating the coverage report, can you help me to clear this warning?

ncsim: *W,COVOPM: Coverage configuration file command "set_covergroup -optimize_model" can be specified to improve the performance and scalability of coverage model containing SV covergroups. It may be noted that subsequent merging of a coverage database saved with this command and a coverage database saved without this command is not allowed.

I am importing sessions which are run by other people to analyse and I would like to remove them from my vManager Regressions tab as they become obsolete. As I am not the original person who run the sims, I cannot "delete" sessions. What are my options? Thanks.

I'm in the process of weeding a regression test list. I have a coverage database from the full regression list and would like to diff it with the coverage database from the new reduced regression test list. If possible I would than like to trace back any buckets covered with the full list, but not with the partial list, into the original tests that covered them.

Is that possible using IMC? if not, is it possible to do from Specman itself?

(Note that we're not using vManager)

Thanks,

Avidan

They say Moore's law is slowing. It may be slowing but it is still running - it has not stopped! And, it has been running at full throttle for quite a few decades now.  The net result of this run? Well, you can't design ICs in isolation from the...(read more)

I’m not talking about carnival funhouse mirrors, but rather the different options for mirroring symbols, vias, and bond fingers in your IC Package layout. The Allegro Package Designer Plus and SiP Layout tools have two distinct styles of m...(read more)

  A few weeks ago, we talked about template text labels for design-specific information. There, we were focused on labels that are specific to the design as a whole: revision information, dates, authors, etc. Today, we’re looking at a diff...(read more)

We’ve all seen bar codes and the more modern QR codes. They’re everywhere you go – items at the grocery store, advertisements and posters, even on websites. Did you know that, with the productivity toolbox in Allegro Package Designe...(read more)

No, this isn’t a Hollywood movie. We’re talking about pieces of plane shapes with no connections to them, not an idyllic private oasis in the Caribbean (sorry). Removing shape islands is something you’ve always been able to do in th...(read more)

If you design wire bond packages, you’re familiar with the need for the bond fingers and rings on the package substrate layers to be exposed through the solder mask layer. If they aren’t, it becomes… rather difficult… to bon...(read more)

In the Allegro back-end layout products like Allegro Package Designer Plus, it would be reasonable to assume that the most often used command is none other than “show element” (shortcut key F4). This command, runnable at nearly any t...(read more)

Molding caps aren’t something we talk about too frequently around here. We all know they exist, and they serve an important purpose of protecting the delicate die from potentially harsh environmental conditions. They impact how well heat can be...(read more)

Those who work in the IC Packaging design space have some unique challenges. We bridge between the IC design world (90/45-degree traces with rectangular and octagonal pins) and the PCB domain (any-angle routing, filled planes, and a multitude of pad ...(read more)

We have talked about aspects of the in-design symbol edit application mode in the past. This is the environment specific to the Allegro Package Designer layout tools allowing you to work on symbol definitions directly in the context of your layout de...(read more)

I am using PCB Editor v17.2-2016.

I tried to do placement by schematic page but not all pages are displayed.

Earlier, I successfully do the placement by schematic pages and it was showing all the pages. But then I decided to delete all placed components and to do placement again.

When I try to do placement by schematic page again, I noticed that only the pages that I have successfully do all the placement previously are missing.

I've redesigned a custom TO220FLAT Package

First I created a TO220shape.ssm  with PCB Editor. Then I created a surface mount T220build.pad in Padstack Editor using TO220shape.ssm. Then I created a TO220FLAT.psm in PCB Editor. I placed 3 Connect pins and 9 Mechanical pins for the TO220 TAB, using standard through-hole pads for better current handling.

Adding those Mechanical pins created many DRC errors caused by the proximity of those pads attached to the TO220shape.

Thru Pin to SMD Pin Spacing (-200.0 0.0) 5 MIL OVERLAP DEFAULT NET SPACING CONSTRAINTS Mechanical Pin "Pad50sq30d" Pin "T220build, 2"

I corrected the situation (so I though) by Waiving those DRC errors, thinking that they could not cause any problem and because that’s what I want, i.e.: 9 through-holes under the TO220 device. The idea being that when this device is mounted flat on the PCB it could carry lots of current via 9 pads that could make a good high current conductor to inner layers.

I then saved the Package and updated all related footprint schematic parts  in Capture. Created a new Netlist. Then I imported the new logic into PCB Editor to reflect that change. When the File > Import > Logic is finished I get no feedback error! (which, for me is a substantial achievement in itself)

Now, in the Design Window I see all those DRC errors popping up again, despite the fact that I waived those DRCs back in the Padstack edition. If I run a Design Rule Check (DRC) Report I will see all those DRC listed again. Now, I understand that I can go ahead and waive all those DRCs (100 in total) but I’m thinking there is got to be a better way of doing this.

Please, any advise is welcome. Thanks

Attached is the latest revision of the venerable Specman-Matlab package (Lead Application Engineer Jangook Lee is the latest to have refreshed it for a customer in Asia to support 64 bit mode.  Look for a guest blog post from him on this package shortly.)

There is a README file inside the package that gives a detailed overview, shows how to run a demo and/or validate it’s installed correctly, and explains the general test flow.  The test file included in the package called "test_get_cmp_mdim.e" shows all the capabilities of the package, including:

* Using Specman to initialize and tear down the Matlab engine in batch mode

* Issuing Matlab commands from e-code, using the Specman command prompt to load .m files, initializing variables, and other operational tasks.

* Transfering data to and from the Matlab engine to Specman / an e language test bench

* Comparing data of previously retrieved Matlab arrays

* Accessing Matlab arrays from e-code without converting them to e list data structure

* Convert Matlab arrays into e-lists

Happy coding!

Team Specman

I want to write a transition coverage on an enumeration. One of the parts of that transition is a queue of the enum. I construct this queue in my constructor. Considering the example below, how would one go about it.

In my coverage bin I can create a range like this A => [queue1Enum[0]:queue1Enum[$]] => [queue2Enum[0]:queue2Enum[$]]. But I only get first and last element then.

typedef enum { red, d_green, d_blue, e_yellow, e_white, e_black } Colors;
 Colors dColors[$];
 Colors eColors[$];
 Lcolors = Colors.first();
 do begin
  if (Lcolors[0].name=='d') begin
   dColors.push_back(Lcolors);
  end
  if (Lcolors[0].name=='e') begin
   eColors.push_back(Lcolors);
  end
 end while(Lcolors != Lcolors.first())

 covergroup cgTest with function sample(Colors c);
   cpTran : coverpoint c{
      bins t[] = (red => dColors =>eColors);   
   }
 endgroup

Hi,

I tried to open my layout by Library Manager, but the Virtuoso CIW window sometimes pops up the follow WARNING messages( as picture depicts). Thus, layout can't open.

Sometimes, I try to reconfigure ICADV12.3 by the iscape and restart my VM and then it incredibly works! But, often not!

So, If anyone knows what it is going on. Please let me know! Thanks!

Appreciated so much   

Verification is the top challenge in mixed-signal design. Bringing analog and digital domains together into unified verification planning, simulating, and debugging is a challenging task for rapidly increasing size and complexity of mixed-signal designs. To more completely verify functionality and performance of a mixed-signal SoC and its AMS IP blocks used to build it, verification teams use simulations at transistor, analog behavioral and real-number model (RNM) and RTL levels, and combination of these.

In recent years, RNM and simulation is being adopted for functional verification by many, due to advantages it offers including simpler modeling requirements and much faster simulation speed (compared to a traditional analog behavioral models like Verilog-A or VHDL-AMS). Verilog-AMS with its wreal continue to be popular choice. Standardization of real number extensions in SystemVerilog (SV) made SV-RNM an even more attractive choice for MS SoC verification.

Verilog-AMS/wreal is scalar real type. SV-RNM offers a powerful ability to define complex data types, providing a user-defined structure (record) to describe the net value. In a typical design, most analog nodes can be modeled using a single value for passing a voltage (or current) from one module to another. The ability to pass multiple values over a net can be very powerful when, for example, the impedance load impact on an analog signal needs to be modeled. Here is an example of a user-defined net (UDN) structure that holds voltage, current, and resistance values:

When there are multiple drives on a single net, the simulator will need a resolution function to determine the final net value. When the net is just defined as a single real value, common resolution functions such as min, max, average, and sum are built into the simulator.  But definition of more complex structures for the net also requires the user to provide appropriate resolution functions for them. Here is an example of a net with three drivers modeled using the above defined structural elements (a voltage source with series resistance, a resistive load, and a current source):

To properly solve for the resulting output voltage, the resolution function for this net needs to perform Norton conversion of the elements, sum their currents and conductances, and then calculate the resolved output voltage as the sum of currents divided by sum of conductances.

With some basic understanding of circuit theory, engineers can use SV-RNM UDN capability to model electrical behavior of many different circuits. While it is primarily defined to describe source/load impedance interactions, its use can be extended to include systems including capacitors, switching circuits, RC interconnect, charge pumps, power regulators, and others. Although this approach extends the scope of functional verification, it is not a replacement for transistor-level simulation when accuracy, performance verification, or silicon correlation are required:  It simply provides an efficient solution for discretely modeling small analog networks (one to several nodes).  Mixed-signal simulation with an analog solver is still the best solution when large nonlinear networks must be evaluated.

Cadence provides a tutorial on EEnet usage as well as the package (EEnet.pkg) with UDN definitions and resolution functions and modeling examples. To learn more, please login to your Cadence account to access the tutorial.

વિશાખાપટ્ટનમ ખાતે ગુરુવારે થયેલી ગેસ લીકની દુર્ઘટનાએ ઇતિહાસની સૌથી મોટી ભોપાલ ગેસ દુર્ઘટનાની સ્મૃતિ તાજા કરી દીધી. દુનિયાએ જોયેલી કેટલીક આવી જ ઔદ્યોગિક દુર્ઘટનાઓ પર એક નજર કરીએ...

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visit News18 Urdu for latest news, breaking news, news headlines and updates from Bageshwar on politics, sports, entertainment, cricket, crime and more.

Linux 2.4 and 2.6 kernel sock_sendpage() NULL pointer dereference exploit. The third and final version of this exploit. This third version features: Complete support for i386, x86_64, ppc and ppc64; The personality trick published by Tavis Ormandy and Julien Tinnes; The TOC pointer workaround for data items addressing on ppc64 (i.e. functions on exploit code and libc can be referenced); Improved search and transition to SELinux types with mmap_zero permission.

The Linux kernel failed to properly initialize some entries the proto_ops struct for several protocols, leading to NULL being derefenced and used as a function pointer. By using mmap(2) to map page 0, an attacker can execute arbitrary code in the context of the kernel. Several public exploits exist for this vulnerability, including spender's wunderbar_emporium and rcvalle's ppc port, sock_sendpage.c. All Linux 2.4/2.6 versions since May 2001 are believed to be affected: 2.4.4 up to and including 2.4.37.4; 2.6.0 up to and including 2.6.30.4

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