This is the 24th installment of The Rationalist, my column for the Times of India.

Back in the last decade, I was a cricket journalist for a few years. Then, around 12 years ago, I quit. I was jaded as hell. Every game seemed like déjà vu, nothing new, just another round on the treadmill. Although I would remember her fondly, I thought me and cricket were done.

And then I fell in love again. Cricket has changed in the last few years in glorious ways. There have been new ways of thinking about the game. There have been new ways of playing the game. Every season, new kinds of drama form, new nuances spring up into sight. This is true even of what had once seemed the dullest form of the game, one-day cricket. We are entering into a brave new world, and the team leading us there is England. No matter what happens in the World Cup final today – a single game involves a huge amount of luck – this England side are extraordinary. They are the bridge between eras, leading us into a Golden Age of Cricket.

I know that sounds hyperbolic, so let me stun you further by saying that I give the IPL credit for this. And now, having woken up you up with such a jolt on this lovely Sunday morning, let me explain.

Twenty20 cricket changed the game in two fundamental ways. Both ended up changing one-day cricket. The first was strategy.

When the first T20 games took place, teams applied an ODI template to innings-building: pinch-hit, build, slog. But this was not an optimal approach. In ODIs, teams have 11 players over 50 overs. In T20s, they have 11 players over 20 overs. The equation between resources and constraints is different. This means that the cost of a wicket goes down, and the cost of a dot ball goes up. Critically, it means that the value of aggression rises. A team need not follow the ODI template. In some instances, attacking for all 20 overs – or as I call it, ‘frontloading’ – may be optimal.

West Indies won the T20 World Cup in 2016 by doing just this, and England played similarly. And some sides began to realise was that they had been underestimating the value of aggression in one-day cricket as well.

The second fundamental way in which T20 cricket changed cricket was in terms of skills. The IPL and other leagues brought big money into the game. This changed incentives for budding cricketers. Relatively few people break into Test or ODI cricket, and play for their countries. A much wider pool can aspire to play T20 cricket – which also provides much more money. So it makes sense to spend the hundreds of hours you are in the nets honing T20 skills rather than Test match skills. Go to any nets practice, and you will find many more kids practising innovative aggressive strokes than playing the forward defensive.

As a result, batsmen today have a wider array of attacking strokes than earlier generations. Because every run counts more in T20 cricket, the standard of fielding has also shot up. And bowlers have also reacted to this by expanding their arsenal of tricks. Everyone has had to lift their game.

In one-day cricket, thus, two things have happened. One, there is better strategic understanding about the value of aggression. Two, batsmen are better equipped to act on the aggressive imperative. The game has continued to evolve.

Bowlers have reacted to this with greater aggression on their part, and this ongoing dialogue has been fascinating. The cricket writer Gideon Haigh once told me on my podcast that the 2015 World Cup featured a battle between T20 batting and Test match bowling.

This England team is the high watermark so far. Their aggression does not come from slogging. They bat with a combination of intent and skills that allows them to coast at 6-an-over, without needing to take too many risks. In normal conditions, thus, they can coast to 300 – any hitting they do beyond that is the bonus that takes them to 350 or 400. It’s a whole new level, illustrated by the fact that at one point a few days ago, they had seven consecutive scores of 300 to their name. Look at their scores over the last few years, in fact, and it is clear that this is the greatest batting side in the history of one-day cricket – by a margin.

There have been stumbles in this World Cup, but in the bigger picture, those are outliers. If England have a bad day in the final and New Zealand play their A-game, England might even lose today. But if Captain Morgan’s men play their A-game, they will coast to victory. New Zealand does not have those gears. No other team in the world does – for now.

But one day, they will all have to learn to play like this.

The India Uncut Blog © 2010 Amit Varma. All rights reserved.
Follow me on Twitter.

Hi supporters,

I got the following error while I run simulation with gate netlist using Cadence Incisive (v15.20):

----

ncsim(64): 15.20-s076: (c) Copyright 1995-2019 Cadence Design Systems, Inc.
ncsim: *E,DLOALB: Design library 'tcbnxxx' not defined while reading module tcbnxxx.MAOxxx:bv (VST).
ncsim: *F,NOSIMU: Errors initializing simulation 'alu_tb' 

----

xxx: standard library name.

My netlist design uses a cell "MAOxxx". I already included the library behavior model to compile using ncverilog, there is no error while compiling. But when I run with ncsim to execute the test, I got above error.

I tried to run with other vendors such as VCS or MTI, they worked.

Please help to understand the error.

Thanks.

xmsim is not exiting the simulation for this error. It is unusual for the simulator to not exit for an error. I have just started using uvm and this is occurring during the randomization step for a sequencer item.

xmsim: *E,RNDCNSTE

I am using -EXIT on the command line.

I am using Xcelium 19.03-s013.

Any insights are appreciated. Thanks.

-Jim

Hello, I need to ask a question regarding hierarchy in allegro schematic. I have created one but now i need to make changes to one section so that its not reflected into the other?

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

Please include a brief summary of how to use it.

Optimizing power can be a very convoluted and crucial process. To make design chips meet throughput goals along with optimal power consumption, you need to plan right from the beginning! (read more)

Key Findings: Advantest, in mixed-signal SoC design, sees 50X speedup, 25 day test reduced to 12 hours, dramatic test coverage increase.

Trolling through the CDNLive archives, I discovered another gem. At the May 2013 CDNLive in Munich, Thomas Henkel and Henriette Ossoinig of Advantest presented a paper titled “Timing-accurate emulation of a mixed-signal SoC using Palladium XP”. Advantest makes advanced electronics test equipment. Among the semiconductor designs they create for these products is a test processor chip with over 100 million logic transistors, but also with lots of analog functions.They set out to find a way to speed up their full-chip simulations to a point where they could run the system software. To do that, they needed about a 50X speed-up. Well, they did it!

Figure 1: Advantest SoC Test Products

To skip the commentary, read Advantest's paper here. 

Problem Statement

Software is becoming a bigger part of just about every hardware product in every market today, and that includes the semiconductor test market. To achieve high product quality in the shortest amount of time, the hardware and software components need to be verified together as early in the design cycle as possible. However, the throughput of a typical software RTL simulation is not sufficient to run significant amounts of software on a design with hundreds of millions of transistors.  

Executing software on RTL models of the hardware means long runs  (“deep cycles”) that are a great fit for an emulator, but the mixed-signal content posed a new type of challenge for the Advantest team.  Emulators are designed to run digital logic. Analog is really outside of the expected use model. The Advantest team examined the pros and cons of various co-simulation and acceleration flows intended for mixed signal and did not feel that they could possibly get the performance they needed to have practical runtimes with software testbenches. They became determined to find a way to apply their Palladium XP platform to the problem.

Armed with the knowledge of the essential relationship between the analog operations and the logic and software operations, the team was able to craft models of the analog blocks using reduction techniques that accurately depicted the essence of the analog function required for hardware-software verification without the expense of a continuous time simulation engine.

The requirements boiled down to the following:

• Generation of digital signals with highly accurate and flexible timing

• Complete chip needs to run on Palladium XP platform

• Create high-resolution timing (100fs) with reasonable emulation performance, i.e. at least 50X faster than simulation on the fastest workstations

Solution Idea

The solution approach chosen was to simplify the functional model of the analog elements of the design down to generation of digital signal edges with high timing accuracy. The solution employed a fixed-frequency central clock that was used as a reference.Timing-critical analog signals used to produce accurately placed digital outputs were encoded into multi-bit representations that modeled the transition and timing behavior. A cell library was created that took the encoded signals and converted them to desired “regular signals”. 

Automation was added to the process by changing the netlisting to widen the analog signals according to user-specified schematic annotations. All of this was done in a fashion that is compatible with debugging in Cadence’s Simvision tool.  Details on all of these facets to follow.

The Timing Description Unit (TDU) Format

The innovative thinking that enabled the use of Palladium XP was the idea of combining a reference clock and quantized signal encoding to create offsets from the reference. The implementation of these ideas was done in a general manner so that different bit widths could easily be used to control the quantization accuracy.

Figure 2: Quantization method using signal encoding

Timed Cell Modeling

You might be thinking – timing and emulation, together..!?  Yes, and here’s a method to do it….

The engineering work in realizing the TDU idea involved the creation of a library of cells that could be used to compose the functions that convert the encoded signal into the “real signals” (timing-accurate digital output signals). Beyond some basic logic cells (e.g., INV, AND, OR, MUX, DFF, TFF, LATCH), some special cells such as window-latch, phase-detect, vernier-delay-line, and clock-generator were created. The converter functions were all composed from these basic cells. This approach ensured an easy path from design into emulation.

The solution was made parameterizable to handle varying needs for accuracy.  Single bit inputs need to be translated into transitions at offset zero or a high or low coding depending on the previous state.  Single bit outputs deliver the final state of the high-resolution output either at time zero, the next falling, or the next rising edge of the grid clock, selectable by parameter. Output transitions can optionally be filtered to conform to a configurable minimum pulse width.

Timed Cell Structure

There are four critical elements to the design of the conversion function blocks (time cells):

                Input conditioning – convert to zero-offset, optional glitch preservation, and multi-cycle path

                Transition sorting – sort transitions according to timing offset and specified precedence

                Function – for each input transition, create appropriate output transition

                Output filtering – Capability to optionally remove multiple transitions, zero-width, pulses, etc.

Timed Cell Caveat

All of the cells are combinational and deliver a result in the same cycle of an input transition. This holds for storage elements as well. For example a DFF will have a feedback to hold its state. Because feedback creates combinational loops, the loops need a designation to be broken (using a brk input conditioning function in this case – more on this later). This creates an additional requirement for flip-flop clock signals to be restricted to two edges per reference clock cycle.

Note that without minimum width filtering, the number of output transitions of logic gates is the sum of all input transitions (potentially lots of switching activity). Also note that the delay cell has the effect of doubling the number of output transitions per input transition.

Figure 3: Edge doubling will increase switching during execution

SimVision Debug Support

The debug process was set up to revolve around VCD file processing and directed and viewed within the SimVision debug tool. In order to understand what is going on from a functional standpoint, the raw simulation output processes the encoded signals so that they appear as high-precision timing signals in the waveform viewer. The flow is shown in the figure below.

Figure 4: Waveform post-processing flow

The result is the flow is a functional debug view that includes association across representations of the design and testbench, including those high-precision timing signals.

Figure 5: Simvision debug window setup

Overview of the Design Under Verification (DUV)

Verification has to prove that analog design works correctly together with the digital part. The critical elements to verify include:

• Programmable delay lines move data edges with sub-ps resolution

• PLL generates clocks with wide range of programmable frequency

• High-speed data stream at output of analog is correct

These goals can be achieved only if parts of the analog design are represented with fine resolution timing.

Figure 6: Mixed-signal design partitioning for verification

How to Get to a Verilog Model of the Analog Design

There was an existing Verilog cell library with basic building blocks that included:

- Gates, flip-flops, muxes, latches

- Behavioral models of programmable delay elements, PLL, loop filter, phase detector

With a traditional simulation approach, a cell-based netlist of the analog schematic is created. This netlist is integrated with the Verilog description of the digital design and can be simulated with a normal workstation. To use Palladium simulation, the (non-synthesizable) portions of the analog design that require fine resolution timing have to be replaced by digital timing representation. This modeling task is completed by using a combination of the existing Verilog cell library and the newly developed timed cells.

Loop Breaking

One of the chief characteristics of the timed cells is that they contain only combinational cells that propagate logic from inputs to outputs. Any feedback from a cell’s transitive fanout back to an input creates a combinational loop that must be broken to reach a steady state. Although the Palladium XP loop breaking algorithm works correctly, the timed cells provided a unique challenge that led to unpredictable results.  Thus, a process was developed to ensure predictable loop breaking behavior. The user input to the process was to provide a property at the loop origin that the netlister recognized and translated to the appropriate loop breaking directives.

Augmented Netlisting

Ease of use and flow automation were two primary considerations in creating a solution that could be deployed more broadly. That made creating a one-step netlisting process a high-value item. The signal point annotation and automatic hierarchy expansion of the “digital timing” parameter helped achieve that goal. The netlister was enriched to identify the key schematic annotations at any point in the hierarchy, including bit and bus signals.

Consistency checking and annotation reporting created a log useful in debugging and evolving the solution.

Wrapper Cell Modeling and Verification

The netlister generates a list of schematic instances at the designated “netlister stop level” for each instance the requires a Verilog model with fine resolution timing. For the design in this paper there were 160 such instances.

The library of timed cells was created; these cells were actually “wrapper” cells comprised of the primitives for timed cell modeling described above. A new verification flow was created that used the behavior of the primitive cells as a reference for the expected behavior of the composed cells. The testing of the composed cells included had the timing width parameter set to 1 to enable direct comparison to the primitive cells. The Cadence Incisive Enterprise Simullator tool was successfully employed to perform assertion-based verification of the composed cells versus the existing primitive cells.

Mapping and Long Paths

Initial experiments showed that inclusion of the fine resolution timed cells into the digital emulation environment would about double the required capacity per run. As previously pointed out, the timed cells having only combinational forward paths creates a loop issue. This fact also had the result of creating some such paths that were more than 5,000 steps of logic. A timed cell optimization process helped to solve this problem. The basic idea was to break the path up by adding flip-flops in strategic locations to reduce combinational path length. The reason that this is important is that the maximum achievable emulation speed is related to combinational path length.

Results

Once the flow was in place, and some realistic test cases were run through it, some further performance tuning opportunities were discovered to additionally reduce runtimes (e.g., Palladium XP tbrun mode was used to gain speed). The reference used for overall speed gains on this solution was versus a purely software-based solution on the highest performance workstation available.

The findings of the performance comparison were startlingly good:

• On Palladium XP, the simulation speed is 50X faster than on Advantest’s fastest workstation

• Software simulation running 25 days can now be run in 12 hours -> realistic runtime enables long-running tests that were not feasible before

• Now have 500 tests that execute once in more than 48 hours

• They can be run much more frequently using randomization and this will increase test coverage dramatically

Steve Carlson

Key Findings:  There are a host of issues that arise in mixed-signal verification.  As discussed in earlier blogs, the industry trends indicate that teams need to prepare themselves for a more mixed world.  The good news is that these top five pitfalls are all avoidable.

It’s always interesting to study the human condition.  Watching the world through the lens of mixed-signal verification brings an interesting microcosm into focus.  The top 5 items that I regularly see vexing teams are:

1. When there’s a bug, whose problem is it?
2. Verification team is the lightning rod
3. Three (conflicting) points of view
4. Wait, there’s more… software
5. There’s a whole new language

Reason 1: When there’s a bug, whose problem is it?

It actually turns out to be a good thing when a bug is found during the design process.  Much, much better than when the silicon arrives back from the foundry of course. Whether by sheer luck, or a structured approach to verification, sometimes a bug gets discovered. The trouble in mixed-signal design occurs when that bug is near the boundary of an analog and a digital domain.

Figure 1.   Whose bug is it?

Typically designers are a diligent sort and make sure that their block works as desired. However, when things go wrong during integration, it is usually also project crunch time. So, it has to be the other guy’s bug, right?

A step in the right direction is to have a third party, a mixed-signal verification expert, apply rigorous methods to the mixed-signal verification task.  But, that leads to number 2 on my list.

Reason 2: Verification team is the lightning rod

Having a dedicated verification team with mixed-signal expertise is a great start, but what can typically happen is that team is hampered by the lack of availability of a fast executing model of the analog behavior (best practice today being a SystemVerilog real number model – SV_RNM). That model is critical because it enables orders of magnitude more tests to be run against the design in the same timeframe. 

Without that model, there will be a testing deficit. So, when the bugs come in, it is easy for everyone to point their finger at the verification team.

Figure 2.  It’s the verification team’s fault

Yes, the model creates a new validation task – it’s validation – but the speed-up enabled by the model more than compensates in terms of functional coverage and schedule.

The postscript on this finger-pointing is the institutionalization of SV-RNM. And, of course, the verification team gets its turn.

Figure 3.  Verification team’s revenge

Reason 3: Three (conflicting) points of view

The third common issue arises when the finger-pointing settles down. There is still a delineation of responsibility that is often not easy to achieve when designs of a truly mixed-signal nature are being undertaken.  

Figure 4.  Points of view and roles

Figure 4 outlines some of the delegated responsibility, but notice that everyone is still potentially on the hook to create a model. It is questions of purpose, expertise, bandwidth, and convention that go into the decision about who will “own” each model. It is not uncommon for the modeling task to be a collaborative effort where the expertise on analog behavior comes from the analog team, while the verification team ensures that the model is constructed in such a manner that it will fit seamlessly into the overall chip verification. Less commonly, the digital design team does the modeling simply to enable the verification of their own work.

Reason 4: Wait, there’s more… software

As if verifying the function of a chip was not hard enough, there is a clear trend towards product offerings that include software along with the chip. In the mixed-signal design realm, many times this software has among its functions things like calibration and compensation that provide a flexible way of delivering guards against parameter drift. When the combination of the chip and the software are the product, they need to be verified together. This puts an enormous premium on fast executing SV-RNM.

Figure 5.   There’s software analog and digital

While the added dimension of software to the verification task creates new heights of complexity, it also serves as a very strong driver to get everyone aligned and motivated to adopt best known practices for mixed-signal verification.  This is an opportunity to show superior ability!

Figure 6.  Change in perspective, with the right methodology

Reason 5: There’s a whole new language

Communication is of vital importance in a multi-faceted, multi-team program.  Time zones, cultures, and personalities aside, mixed-signal verification needs to be a collaborative effort.  Terminology can be a big stumbling block in getting to a common understanding. If we take a look at the key areas where significant improvement can usually be made, we can start to see the breadth of knowledge that is required to “get” the entirety of the picture:

• Structure – Verification planning and management
• Methodology – UVM (Unified Verification Methodology – Accellera Standard)
• Measure – MDV (Metrics-driven verification)
• Multi-engine – Software, emulation, FPGA proto, formal, static, VIP
• Modeling – SystemVerilog (discrete time) down to SPICE (continuous time)
• Languages – SystemVerilog, Verilog, Verilog-AMS, VHDL, SPICE, PSL, CPF, UPF

Each of these areas has its own jumble of terminology and acronyms. It never hurts to create a team glossary to start with. Heck, I often get my LDO, IFV, and UDT all mixed up myself.

Summary

Yes, there are a lot of things that make it hard for the humans involved in the process of mixed-signal design and verification, but there is a lot that can be improved once the pain is felt (no pain, no gain is akin to no bugs, no verification methodology change). If we take a look at the key areas from the previous section, we can put a different lens on them and describe the value that they bring:

• Structure – Uniformly organized, auditable, predictable, transparency
• Methodology – Reusable, productive, portable, industry standard
• Measure – Quantified progress, risk/quality management, precise goals
• Multi-engine – Faster execution, improved schedule, enables new quality level
• Modeling – Enabler, flexible, adaptable for diverse applications/design styles
• Languages – Flexible, complete, robust, standard, scalability to best practices

With all of this value firmly in hand, we can turn our thoughts to happier words:

…  stay tuned for more!

 Steve Carlson

We have all heard the sayings “Less is more” and “Keep it simple”. Electromagnetic simulation is an activity where following that advice has enormous payoffs. In this blog I’ll talk about some of my experiences with how Virtuoso RF Solution’s shape simplification feature has helped my customers get significant performance improvements with minimal impacts on accuracy. (read more)

This blog discusses key features of concurrently editing a hierarchical cellview.(read more)

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

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

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

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

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

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

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

Coronavirus સામે America ની હાલત કફોડી, Trump એ China પર લગાવ્યા આરોપ

India Lockdown: Delhi માં દારૂ બાદ વેટમાં વધારો થતાં પેટ્રોલ-ડીઝલ પણ મોંઘું

Special Report: શું Chinaમાં પાછી ફરી Coronavirusની 'સેકન્ડ વેવ'?

શુભ મૂર્હૂતમાં તમે ઓમ નમ: શિવાયનો જાપ કરી કરો શિવજીને પ્રસન્ન

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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