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Former Auburn defensive tackle Derrick Brown became the first player chosen in the NFL draft's first round to agree on a deal. The Panthers will sign him to a four-year, fully guaranteed contract worth $23.62 million.

With more and more SoCs employing sophisticated interconnect IP to link multiple processor cores, caches, memories, and dozens of other IP functions, the designs are enabling a new generation of low-power servers and high-performance mobile devices. The complexity of the interconnects and their advanced configurability contributes to already formidable design and verification challenges which lead to the following questions:

While your interconnect subsystem might have a correct functionality, are you starving your IP functions of the bandwidth they need? Are requests from latency-critical initiators processed on time? How can you ensure that all applications will receive the desired bandwidth in steady-state and corner use-cases?

To answer these questions, Cadence recommends the Performance Verification Methodology to ensure that the system performance meets requirements at the different levels:

1. Performance characterization: The first level of verification aims to verify the path-to-path traffic measuring the performance envelope. It targets integration bugs like clock frequency, buffer sizes, and bridge configuration. It requires to analyze the latency and bandwidth of design’s critical paths.
2. Steady state workloads: The second level of verification aims to verify the master-by-master defined loads using traffic profiles. It identifies the impact on bandwidth when running multi-master traffic with various Quality-of-Service (QoS) settings. It analyzes the DDR sub-system’s efficiency, measures bandwidth and checks whether masters’ QoS requirements are met.
3. Application specific use cases: The last level of verification simulates the use-cases and reaches the application performance corner cases. It analyzes the master-requested bandwidth as well as the DDR sub-system’s efficiency and bandwidth.

Cadence has developed a set of tools to assist customers in performance validation of their SoCs. Cadence Interconnect Workbench simplifies the setup and measurement of performance and verification testbenches and makes debugging of complex system behaviors a snap. The solution works with Cadence Verification IPs and executes on the Cadence Xcelium® Enterprise Simulator or Cadence Palladium® Accellerator/Emulator, with coverage results collected and analyzed in the Cadence vManager  Metric-Driven Signoff Platform.

To verify the performance of the Steady State Workloads, Arm has just released a new AMBA Adaptive Traffic Profile (ATP) specification which describes AMBA abstract traffic attributes and defines the behavior of the different traffic profiles in the system.

With the availability of Cadence Interconnect Workbench and AMBA VIP support of ATP, early adopters of the AMBA ATP specification can begin working immediately, ensuring compliance with the standard, and achieving the fastest path to SoC performance verification closure.

For more information on the AMBA Adaptive Traffic Profile, you can visit Dimitry's blog on AMBA Adaptive Traffic Profiles: Addressing The Challenge. 

More information on Cadence Interconnect Workbench solution is available at Cadence Interconnect Solution webpage.

Thierry

Verification of a USB4 router design is not just about USB4 but also about the inclusion of the three other major protocols namely, USB3, DisplayPort (DP), and PCI Express (PCIe). These protocols can be simultaneously tunneled through a USB4 router. Put in simple terms, such tunneling involves the conversion of the respective native USB3, DP, or PCIe protocol traffic into the USB4 transport layer packets, which are tunneled through a USB4 fabric, and converted back into the respective original native protocol traffic.

It may sound simple but is perhaps not.

There are several aspects in a router that come into picture to carry out this task of conversion of native protocol traffic, route it to the intended destination, and then convert it back to the original form. Some of those are the USB3, DP and PCIe protocol adapters, transport mechanism using routing, flow control, paths, path set-up and teardown, control and configuration, configuration spaces.

That is not all. There are core USB4 specific logical layer intricacies as well, which carry out the tasks of ensuring that all the USB4 ports and links are working as desired to provide up to 40Gbps speed and that the USB4 traffic flows through out the fabric in the intended way. These bring on the table features like High Speed link, ordered sets, lane initialization, lane adapter state machine, low power, lane bonding, RS-FEC, side band channel, sleep and wake, error checking.

All of these put together give rise to a very large verification space against which a USB4 router design should be verified. If we were to break down this space it can be broadly put in the following major dimensions,

• Protocol Adapter Layer
  • USB3 tunneling
  • DP tunneling
  • PCIe tunneling
• Host Interface Adapter Layer
• Transport Layer
  • Flow control
  • Routing
  • Paths
• Configuration layer and control packet protocol
• Configuration spaces
• Logical Layer

The independent verification of these dimensions is not all that would qualify the design as verified. They have to be verified in various combinations of each other too. Overall, all the parts of a USB4 router system need to be working together coherently.

For example, the following diagram depicts the various layers that a USB4 router may comprise of,

A USB4 router or a domain of routers does not work on its own. There is a Connection Manager per domain, which is a software-based entity managing a domain. A router provides the various capabilities for a Connection Manager to carry out its responsibilities of managing a domain.

It would not be an exaggeration to say that the spectrum of verification of a USB4 router ranges from the very minute details of logical layer to the system-level like multiple dependencies as the whole USB4 system is brought up layer by layer, step-by-step.

Cadence has a mature Verification IP solution that can help in the verification of USB4 designs. Cadence has taken an active part in the working group that defined the USB4 specification and has created a comprehensive Verification IP that is being used by multiple members in the last two years.

If you plan to have a USB4 compatible design, you can reduce the risk of adopting a new technology by using our proven and mature USB4 Verification IP. Please contact your Cadence local account team for more details and to get connected.

Verifying lane adapter state machine in a router design is quite an involved task and needs verification from several aspects including that for its link training functionality.

The diagram below shows two lane adapters connected to each other and each going through the link training process. Each training sub-state transition is contingent on conditions for both transmission and reception of relevant ordered sets needed for a transition. Until conditions for both are satisfied an adapter cannot transition to the next training sub-state.

As deduced from the lane adapter state machine section of USB4 specification, the reception condition for the next training sub-state transition is less strict than that of the transmission condition. For ex., for LOCK1 to LOCK2 transition, the reception condition requires only two SLOS symbols in a row being detected, while the transmission condition requires at least four complete SLOS1 ordered sets to be sent.

From the above conditions in the specification, it is a possibility that a lane adapter A may detect the two SLOS or TS ordered sets, being sent by the lane adapter B on the other end, in the very beginning as soon as it starts transmitting its own SLOS or TS ordered sets. On the other hand, it is also a possibility that these SLOS or TS ordered sets are not yet detected by lane adapter A even when it has met the condition of sending minimum number of SLOS or TS ordered sets.

In such a case, lane adapter A, even though it has satisfied the transmission condition cannot transition to the next sub-state because the reception condition is not yet met. Hence lane adapter A must first wait for the required number of ordered sets to be detected by it before it can go to the next sub-state. But this wait cannot be endless as there are timeouts defined in the specification, after which the training process may be re-attempted.

This interlocked way of operation also ensures that state machine of a lane adapter does not go out of sync with that of the other lane adapter. Such type of scenarios can occur whenever lane adapter state machine transitions to the training state from other states.

Cadence has a mature Verification IP solution for the verification of various aspects of the logical layer of a USB4 router design, with verification capabilities provided to do a comprehensive verification of it.

There has been so much hype about the “Internet of Things” (IoT) that it is refreshing to hear about a cutting-edge development project that can bring concrete benefits to millions of people. That project is the ongoing development of the Google Smart Contact Lens, and it was detailed in a keynote speech June 8 at the Design Automation Conference (DAC 2015).

The keynote speech was given by Brian Otis (right), a director at Google and a research associate professor at the University of Washington. The “smart lens” that the project envisions is essentially a disposable contact lens that fits on an eye and continuously monitors blood glucose levels. This is valuable information for anyone who has, or may someday have, diabetes.

Since he was speaking to an engineering audience, Otis focused on the challenges behind building such a device, and described some of the strategies taken by Google and its partner, Novartis. The project required new approaches to miniaturization, low-power design, and connectivity, as well as a comfortable and reliable silicon-to-human interface. Otis discussed the “why” as well and showed how the device could potentially save or improve millions of lives.

Millions of Users

First, a bit of background. Google announced the smart lens project in a blog post in January 2014. Since then it has been featured in news outlets including Forbes, Time, and the Wall Street Journal. In March 2015, Time reported that Google has been granted a patent for a smart contact lens.

The smart lens monitors the level of blood glucose by looking at its concentration in tears. The lens includes a wireless system on chip (SoC) and a miniaturized glucose sensor. A tiny pinhole in the lens allows tear fluid to seep into the sensor, and a wireless antenna handles communications to the wireless devices.

“We figure that if we can solve a huge problem, it is probably worth doing,” Otis said. “Diabetes is one example.” He noted 382 million people worldwide have diabetes today, and that 35% of the U.S. population may be pre-diabetic. Today, diabetics must *** their fingers to test blood glucose levels, a procedure that is invasive, painful, and subject to infrequent monitoring.

According to Otis, the smart contact lens represents a “new category of wearable devices that are comfortable, inexpensive, and empowering.” The lens does sensor data logging and uses a portable instrument to measure glucose levels. It is thin, cheap, and disposable, he said.

Moreover, the lens is not just for people already diagnosed with diabetes—it’s for anyone who is pre-diabetic, or may be at risk due to genetic predisposition. “If we are pro-active rather than re-active,” Otis said, “Instead of waiting until a person has full-fledged diabetes, we could make a huge difference in peoples’ lives and lower the costs of treating them.”

Technical Challenges

No one has built anything quite like the smart lens, so researchers at Google and Novartis are treading new ground. Otis identified three key challenges:

• Miniaturization: Everything must be really small—the SoC, the passive components, the power supply. Components must be flexible and cheap, and support thin-film integration.
• Platform: Google has developed a reusable platform that includes tiny, always-on wireless sensors, ultra low-power components, and standards-based interfaces.
• Data: Researchers are looking for the best ways to get the resulting data into a mobile device and onto the cloud.

Comfort is another concern. “This is not intended to be for the most severe cases,” Otis said. “This is intended to be for all of us as a pro-active way of improving our lifestyles.”

The platform provides a bidirectional encrypted wireless link, integrated power management, on-chip memory, standards-based RFID link, flexible sensor interface, high-resolution potentiostat sensor, and decoupling capacitors. Most of these capabilities are provided by the standard CMOS SoC, which is a couple hundred microns on a side and only “tens of microns” thick.

Otis noted that unpackaged ICs are typically 250 microns thick when they come back from the foundry. Thus, post-processing is needed so the IC will fit into a contact lens.

Furthermore, the design requires precision analog circuitry and additional environmental sensors. “Some of this stuff sounds mundane but it is really hard, especially when you find out you can’t throw large decoupling capacitors and bypass capacitors onto a board, and all that has to be re-integrated into the chip,” Otis said.

Sensor Challenges

Getting information from the human body is challenging. The smart lens sensor does a direct chemical measurement on the surface of the eye. The sensor is designed to work with very low glucose concentrations. This is because the concentration of glucose in tears is an order of magnitude lower than it is in blood.

In brief, the sensor has two parallel plates that are coated with an enzyme that converts glucose into hydrogen peroxide, which flows around the electrodes of the sensor. This is actually a fairly standard way of doing glucose monitoring. However, the smart lens sensor has two electrodes compared to the typical three.

In manufacturing, it is essential to keep costs low. Otis outlined a three-step manufacturing process:

• Start with the bottom layer, and mold a contact lens in the way you typically would.
• Add the electronics package on top of that layer.
• Build a second layer that encapsulates the electronics and provides the curvature needed for comfort and vision correction.

Beyond the technical challenges are the “clinical” challenges of working with human beings. The human body “is messy and very variable,” Otis said. This variability affects sensor performance and calibration, RF/electro-magnetic performance, system reliability, and comfort.

The final step is making use of the data. “We need to get the data from the device into a phone, and then display it so users can visualize the data,” Otis said. This provides “actionable feedback” to the person who needs it. Eventually, the data will need to be stored in the cloud.

As he concluded his talk, Otis noted that the platform his group developed may have many applications beyond glucose monitoring. “There is a lot you can do with a bunch of logic and sensing capability,” he said, “and there are hundreds of biomarkers beyond glucose.” Clearly this will be an interesting technology to watch.

Richard Goering

Related Blog Post

- Gary Smith at DAC 2015: How EDA Can Expand Into New Directions

Hi! 

In my design, there is an one hold violation on scan path, test data is corrupted during scan cycles (when i run verilog simulation of test vectors). I created constraint 'falsepath' to 'TI' input of violated flop and load it into Modus, but this does not have effect.

Can enyone explain to me, does 'falsepath' constraint affects scan path (from Q to TI/SI input, i.e. during SCAN procedure) or this constraint is only for functional mode (ie affects TEST cycle only - to 'D' input)?

I hope resolve this problem this by using some modus design constraints or any other method.

Hello, i have a logic output from a D-flipflop which generates a reset signal with variable pulse width. I want to stretch this LOW pulse width with an extra 100ns added to the original pulse width digitally, is there any way to do that?

Dear all,

I am using Conformal Constraint Designer (Version 17.1) to analyse a SystemVerilog based design.

While performing default HDL checks it finds  some violations (issues) in RTL and complains (warnings, etc) about RTL checks and others.

My questions:

Is there any directive which I can add to RTL (system Verilog) so that particular line of code or signal is ignored or not checked for HDL or RTL checks.

I can set ignore rules in rule manager (gui) but it does not seems effective if code line number changes or new signals are introduced.

What is the best way to customize default_hdl_rules ?

I will be grateful for your guidance.

Thanks for your time.

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

Large-signal S-parameters (LSSPs) are an extension of small-signal S-parameters and are defined as the ratio of reflected (or transmitted) waves to incident waves. (read more)

Vegas, here we come. All of us fun EDA engineers at once. Be prepared, next week’s Design Automation Conference will be busy! The trends I had outlined after last DAC in 2018—system design, cloud, and machine learning—have...(read more)

Iam new to Package design SIP tool.

I had created the DIE package using SIP. Kindly give the direction how to map the created DIE package in Allegro pcb editor 17.2 ver.

In Allegro design capture CIS tool we had created the schematics file. The DIE which we are using is having 100pins, We had created the DIE in SIP tool. Out of 100 Die pins, only 90 pins is getting connected others are NC pins. We had mapped the Bond fingers only for 90 Die pins in the SIP package. But in the Schematics we had created the DIE logic symbol for 100 pins. Please advice whether we can able to import the DIE package in the allegro tool. In this scenario while importing the 100 pin DIE package in allegro pcb editor will the net connectivity will be shown from the DIE pad to Bond fingers and from Bond fingers to respective components? Please suggest whether we are going in the right path or please advice what we have to proceed with.

Thanks in Advance,

Rajesh

Have you ever manufactured a printed circuit board (PCB) without analyzing all the routed signal traces? Most designers will say “yes, all the time.” Trace widths and spacing are set by constraints,...

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Everyone keeps talking about “the cloud” this and “the cloud” that these days—but you’re a semiconductor designer. Everyone keeps saying “the cloud” is revolutionizing all aspects of electronics design—but what does it mean for you? Cadence's own Tom Hackett discussed this in a presentation at the Cadence Theater during DAC 2019.

What people refer to as “the cloud” is commonly divided into three categories: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and software as a Service (SaaS). With IaaS, you bring your own software—i.e. loading your owned or appropriately licensed tools onto cloud hardware that you rent by the minute. This service is available from providers like Google Cloud Platform, Amazon Web Service, and Microsoft Azure. In PaaS (also available from the major cloud providers), you create your own offering using capabilities and a software design environment provided by the cloud vendor that makes subsequent scaling and distribution really easy because the service was “born in the cloud”.  Lastly, there’s SaaS, where the cloud is used to access and manage functionality and data without requiring users to set up or manage any of the underlying infrastructure used to provide it.  SaaS companies like Workday and Salesforce deliver their value in this manner.  The Cadence Cloud portfolio makes use of both IaaS and SaaS, depending on the customers’ interest.  Cadence doesn’t have PaaS offerings because our customers don’t create their own EDA software from building blocks that Cadence provides.

All of these designations are great, but you’re a semiconductor designer. Presumably you use Workday or some similar software, or have in the past when you were an intern, but what about all of your tools? Those aren’t on the cloud.

Wait—actually, they are.

Using EDA tools in the cloud allows you to address complexity and data explosion issues you would have to simply struggle through before. Since you don’t have to worry about having the compute-power on-site, you can use way more power than you could before. You may be wary about this new generation of cloud-based tools, but don’t worry: the old rules of cloud computing no longer apply. Cloud capacity is far larger than it used to be, and it’s more secure. Updates to scheduling software means that resource competition isn’t as big of a deal anymore. Clouds today have nearly unlimited capacity—they’re so large that you don’t ever need to worry about running out of space.

The vast increase in raw compute available to designers through the cloud makes something like automotive functional safety verification, previously an extremely long verification task, doable in a reasonable time frame. With the cloud, it’s easy to scale the amount of compute you’re using to fit your task—whether it’s an automotive functional safety-related design or a small one.

Nowadays, the Cadence Cloud Portfolio brings you the best and brightest in cloud technology. No matter what your use case is, the Cadence Cloud Portfolio has a solution that works for you. You can even access the Palladium Cloud, allowing you to try out the benefits of an accelerator without having to buy one.

Cloud computing is the future of EDA. See the future here.

All PCB designers know the importance of proper power delivery for successful board design. Integrated circuits need the power to turn on, and ICs with marginal power delivery will not operate reliably. Since power planes can...(read more)

What is a Power Distribution Network (PDN) after all but resistance, inductance, and capacitance in the PCB and components? And, of course, it is there to deliver the right current and voltage to each component on your PCB. But is that all? Are there oth...(read more)

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So, what if you can figure out all that can go wrong when your product is being assembled early on? Not guess but know and correct at an early stage – not wait for the fabricator or manufacturer to send you a long report of what needs to change. That’s why Design for Assembly (DFA) rules(read more)

All engineers can enhance their mixed-signal low-power structural verification productivity by learning while doing with a PIEA RAK (Power Intent Export Assistant Rapid Adoption Kit). They can verify the mixed-signal chip by a generating macromodel for their analog block automatically, and run it through Conformal Low Power (CLP) to perform a low power structural check.  

The power structure integrity of a mixed-signal, low-power block is verified via Conformal Low Power integrated into the Virtuoso Schematic Editor Power Intent Export Assistant (VSE-PIEA). Here is the flow.

Applying the flow iteratively from lower to higher levels can verify the power structure.

Cadence customers can learn more in a Rapid Adoption Kit (RAK) titled IC 6.1.5 Virtuoso Schematic Editor XL PIEA, Conformal Low Power: Mixed-Signal Low Power Structural Verification.

• To read the overview presentation, click on following link: PIEA Overview
• To download this PIEA RAK click on following link: PIEA RAK Download

The RAK includes Rapid Adoption Kit with demo design (instructions are provided on how to setup the user environment). It Introduces the Power Intent Export Assistant (PIEA) feature that has been implemented in the Virtuoso IC615 release.  The power intent extracted is then verified by calling Conformal Low Power (CLP) inside the Virtuoso environment.

• Last Update: 11/15/2012.
• Validated with IC 6.1.5 and CLP 11.1

The RAK uses a sample test case to go through PIEA + CLP flow as follows:

• Setup for PIEA
• Perform power intent extraction
• CPF Import: It is recommended to Import macro CPF, as oppose to designing CPF for sub-blocks. If you choose to import design CPF files please make sure the design CPF file has power domain information for all the top level boundary ports
• Generate macro CPF and design CPF
• Perform low power verification by running CLP

It is also recommended to go through older RAKs as prerequisites.

• Conformal Low Power, RTL Compiler and Incisive: Low Power Verification for Beginners
• Conformal Low Power: CPF Macro Models
• Conformal Low Power and RTL Compiler: Low Power Verification for Advanced Users

To access all these RAKs, visit our RAK Home Page to access Synthesis, Test and Verification flow

Note: To access above docs, use your Cadence credentials to logon to the Cadence Online Support (COS) web site. Cadence Online Support website https://support.cadence.com/ is your 24/7 partner for getting help and resolving issues related to Cadence software. If you are signed up for e-mail notifications, you can receive new solutions, Application Notes (Technical Papers), Videos, Manuals, and more.

You can send us your feedback by adding a comment below or using the feedback box on Cadence Online Support.

Sumeet Aggarwal

DAC is right around the corner! On the demo floor at Cadence® Booth #2214, we will demonstrate how to use the Cadence mixed-signal and low-power solution to design, verify, and implement a microcontroller-based mixed-signal design. The demo design architecture is very similar to practical designs of many applications like power management ICs, automotive controllers, and the Internet of Things (IoT). Cadene tools demonstrated in this design include Virtuoso® Schematic Editor, Virtuoso Analog Design Environment, Virtuoso AMS Designer, Virtuoso Schematic Model Generator, Virtuoso Power Intent Assistant, Incisive® Enterprise Simulator with DMS option, Virtuoso Digital Implementation, Virtuoso Layout Suite, Encounter® RTL Compiler, Encounter Test, and Conformal Low Power. An extended version of this demo will also be shown at the ARM® Connected Community Pavilion Booth #921.

For additional highlights on Cadence mixed-signal and low-power solutions, stop by our booth for:

• The popular book, Mixed-signal Methodology Guide, which will be on sale during DAC week!
• A sneak preview of the eBook version of the Mixed-signal Methodology Guide
• Customer presentations at the Cadence DAC Theater
  • 9am, Tuesday, June 4  ARM  Low-Power Verification of A15 Hard Macro Using CLP 
  • 10:30am, Tuesday, June 4  Silicon Labs  Power Mode Verification in Mixed-Signal Chip
  • 12:00pm, Tuesday, June 4  IBM  An Interoperable Flow with Unified OA and QRC Technology Files
  • 9am, Wednesday, June 5  Marvell  Low-Power Verification Using CLP
  • 4pm, Wednesday, June 5  Texas Instruments  An Inter-Operable Flow with Unified OA and QRC Technology Files
• Partner presentations at the Cadence DAC Theater
  • 10am, Monday, June 3  X-Fab  Rapid Adoption of Advanced Cadence Design Flows Using X-FAB's AMS Reference Kit
  • 3:30pm, Monday, June 3  TSMC TSMC Custom Reference Flow for 20nm -  Cadence Track
  • 9:30am,Tuesday, June 4  TowerJazz   Substrate Noise Isolation Extraction/Model Using Cadence Analog Flow
  • 12:30pm, Wednesday, June 5  GLOBALFOUNDRIES  20nm/14nm Analog/Mixed-signal Flow
  • 2:30pm, Wednesday, June 5  ARM  Cortex®-M0 and Cortex-M0+: Tiny, Easy, and Energy-efficient Processors for Mixed-signal Applications
• Technology sessions at suites
  • 10am, Monday, June 3    Low-power Verification of Mixed-signal Designs
  • 2pm, Monday, June 3      Advanced Implementation Techniques for Mixed-signal Designs
  • 2pm, Monday, June 3      LP Simulation: Are You Really Done?
  • 4pm, Monday, June 3      Power Format Update: Latest on CPF and IEEE 1801  
  • 11am, Wednesday, June 5   Mixed-signal Verification
  • 11am, Wednesday, June 5   LP Simulation: Are You Really Done?
  • 4pm, Wednesday, June 5   Successful RTL-to-GDSII Low-Power Design (FULL)
  • 5pm, Wednesday, June 5   Custom/AMS Design at Advanced Nodes

We will also have three presentations at the Si2 booth (#1427):

• 10:30am, Monday, June 3   An Interoperable Implementation Solution for Mixed-signal Design
• 11:30am, Tuesday, June 4   Low-power Verification for Mixed-signal Designs Using CPF
• 10:30am, Wednesday, June 5   System-level Low-power Verification Using Palladium

We have a great program at DAC. Click the link for complete Cadence DAC Theater and Technology Sessions. Look forward to seeing you at DAC!     

Hi,
I am new to the circuit design and troubleshooting. My project is to design a trans-impedance amplifier using Cadence that can amplify a signal coming from a photodiode. I started out with the regulated cascode configuration as shown in the circuit below. I look at the frequency response using AC simulation and it looks like a high pass (/net 5). The results doesn ot show any gain (transient response), or expected low-pass roll-off in the AC response.

First thing, I looked into the operating regions of the MOSFETs and adjusted the input dc voltage of the Vsin to 0.5 to make sure that the T0, T1 mosfets are in saturation(checked this with the print->dc operating points). Beyond this point, I am not sure on how to proceed and interpret the results to make changes. Any help would be greatly appreciated.

Thanks,

-Rakesh.

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.

Hi

     I want develope basic circuit of DC motor which consist of resistor, inductor and back emf in capture and check its simulation in pspice, for reference I have attached image and link.

https://www.precisionmicrodrives.com/content/ab-025-using-spice-to-model-dc-motors/ .

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)

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Variants seem to be defined as present or not present.

Is there a variant that can assign different parts to the same reference designator? i.e.  R17 can be either 0 ohm 0805 jumper or 12k ohms 0805 resistor.

The simplest way I can think of is to use two parts with the same footprint and overlay them.

Is there a more functional way of doing this?  So that the variant would put the correct part in the BOM and the parts would of course have the same identical footprint.

Hello All,

I'm currently using OrCAD PCB Designer Professional w/ PSpice (version 16.6-2015).  In the 'Design Object Find Filter' side bar, all options are grayed out and unselectable.  I did attempt to 'Reset UI to Cadence Default' without any luck.  A colleague has no issues with the identical file on his computer.  Any guidance would be much appreciated.  Thanks!

George

Hi,

I have a new customer that uses Allegro Design entry HDL for the schematic and have a few questions.

1. How do you get pin/gate swaps into the symbols in the schematic ?

2. How do you transfer them to the pcb editor ?

3. How do you back annotate the swaps from the pcb editor to the schematic ?

4. How do you stop the export/Import physical from updating the constraints in the pcb file ? 

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 

Try looking at www.solidwoodkitchen.co.uk. They have some amazing designs and prices.

Kitchen Design Manchester

Hello,

I find a strange issue when using design variable -> right-click -> copy from cellview in assembler. Cadence version is IC618-64b. 500.9

In fact, I set the value of variable (e.g., AAA = 100), then after I right-click -> copy from cellview, AAA's is updated to other value. In my opinion "copy from cellview" should only update the missing variable to the list, but not change any variable value. 

Is there any mechanism could change variable value when using "copy from cellview"?

Thanks

Let’s review a key characteristic feature of Cadence Liberate AMS Mixed-Signal Characterization that offers to you ease of use along with many other benefits like automation of standard Liberty model creation and improvement of up to 20X throughput.(read more)

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:  Nearly 100% of SoCs are mixed-signal to some extent.  Every one of these could benefit from the use of a metrics-driven unified verification methodology for mixed-signal (MD-UVM-MS), but the modeling step is the biggest hurdle to overcome.  Without the magical models, the process breaks down for lack of performance, or holes in the chip verification.

In the last installment of The Low Road, we were at the mixed-signal verification party. While no one talked about it, we all saw it: The party was raging and everyone was having a great time, but they were all dancing around that big elephant right in the middle of the room. For mixed-signal verification, that elephant is named Modeling.

To get to a fully verified SoC, the analog portions of the design have to run orders of magnitude faster than the speediest SPICE engine available. That means an abstraction of the behavior must be created. It puts a lot of people off when you tell them they have to do something extra to get done with something sooner. Guess what, it couldn’t be more true. If you want to keep dancing around like the elephant isn’t there, then enjoy your day. If you want to see about clearing the pachyderm from the dance floor, you’ll want to read on a little more….

Figure 1: The elephant in the room: who’s going to create the model?

 Whose job is it?

Modeling analog/mixed-signal behavior for use in SoC verification seems like the ultimate hot potato.  The analog team that creates the IP blocks says it doesn't have the expertise in digital verification to create a high-performance model. The digital designers say they don’t understand anything but ones and zeroes. The verification team, usually digitally-centric by background, are stuck in the middle (and have historically said “I just use the collateral from the design teams to do my job; I don’t create it”).

If there is an SoC verification team, then ensuring that the entire chip is verified ultimately rests upon their shoulders, whether or not they get all of the models they need from the various design teams for the project. That means that if a chip does not work because of a modeling error, it ought to point back to the verification team. If not, is it just a “systemic error” not accounted for in the methodology? That seems like a bad answer.

That all makes the most valuable guy in the room the engineer, whose knowledge spans the three worlds of analog, digital, and verification. There are a growing number of “mixed-signal verification engineers” found on SoC verification teams. Having a specialist appears to be the best approach to getting the job done, and done right.

So, my vote is for the verification team to step up and incorporate the expertise required to do a complete job of SoC verification, analog included. (I know my popularity probably did not soar with the attendees of DVCON with that statement, but the job has to get done).

It’s a game of trade-offs

The difference in computations required for continuous time versus discrete time behavior is orders of magnitude (as seen in Figure 2 below). The essential detail versus runtime tradeoff is a key enabler of verification techniques like software-driven testbenches. Abstraction is a lossy process, so care must be taken to fully understand the loss and test those elements in the appropriate domain (continuous time, frequency, etc.).

Figure 2: Modeling is required for performance

AFE for instance

The traditional separation of baseband and analog front-end (AFE) chips has shifted for the past several years. Advances in process technology, analog-to-digital converters, and the desire for cost reduction have driven both a re-architecting and re-partitioning of the long-standing baseband/AFE solution. By moving more digital processing to the AFE, lower cost architectures can be created, as well as reducing those 130 or so PCB traces between the chips.

There is lots of good scholarly work from a few years back on this subject, such as Digital Compensation of Dynamic Acquisition Errors at the Front-End of ADCS and Digital Compensation for Analog Front-Ends: A New Approach to Wireless Transceiver Design.

Figure 3: AFE evolution from first reference (Parastoo)

The digital calibration and compensation can be achieved by the introduction of a programmable solution. This is in fact the most popular approach amongst the mobile crowd today. By using a microcontroller, the software algorithms become adaptable to process-related issues and modifications to protocol standards.

However, for the SoC verification team, their job just got a whole lot harder. To determine if the interplay of the digital control and the analog function is working correctly, the software algorithms must be simulated on the combination of the two. That is, here is a classic case of inseparable mixed-signal verification.

So, what needs to be in the model is the big question. And the answer is, a lot. For this example, the main sources of dynamic error at the front-end of ADCs are critical for the non-linear digital filtering that is highly frequency dependent. The correction scheme must be verified to show that the nonlinearities are cancelled across the entire bandwidth of the ADC. 

This all means lots of simulation. It means that the right level of detail must be retained to ensure the integrity of the verification process. This means that domain experience must be added to the list of expertise of that mixed-signal verification engineer.

Back to the pachyderm

There is a lot more to say on this subject, and lots will be said in future posts. The important starting point is the recognition that the potential flaw in the system needs to be examined. It needs to be examined by a specialist.  Maybe a second opinion from the application domain is needed too.

So, put that cute little elephant on your desk as a reminder that the beast can be tamed.

Steve Carlson

Related stories

- It’s Late, But the Party is Just Getting Started

Key Findings: Many more design teams will be reaching the mixed-signal methodology tipping point in 2015. That means you need to have a (verification) plan, and measure and execute against it.

As 2014 draws to a close, it is time to look ahead to the coming years and make a plan. While the macro view of the chip design world shows that is has been a mixed-signal world for a long time, it is has been primarily the digital teams that have rapidly evolved design and verification practices over the past decade. Well, I claim that is about to change. 2015 will be a watershed year for many more design teams because of the following factors:

• 85% of designs are mixed signal, and it is going to stay that way (there is no turning back)
• Advanced node drives new techniques, but they will be applied on all nodes
• Equilibrium of mixed-signal designs being challenged, complexity raises risk level
• Tipping point signs are evident and pervasive, things are going to change
• The convergence of “big A” and “big D” demands true mixed-signal practices

Reason 1: Mixed-signal is dominant

To begin the examination of what is going to change and why, let’s start with what is not changing. IBS reports that mixed signal accounts for over 85% of chip design starts in 2014, and that percentage will rise, and hold steady at 85% in the coming years. It is a mixed-signal world and there is no turning back!

Figure 1. IBS: Mixed-signal design starts as percent of total

The foundational nature of mixed-signal designs in the semiconductor industry is well established. The reason it is exciting is that a stable foundation provides a platform for driving change. (It’s hard to drive on crumbling infrastructure.  If you’re from California, you know what I mean, between the potholes on the highways and the earthquakes and everything.)

Reason 2: Innovation in many directions, mostly mixed-signal applications

While the challenges being felt at the advanced nodes, such as double patterning and adoption of FinFET devices, have slowed some from following onto to nodes past 28nm, innovation has just turned in different directions. Applications for Internet of Things, automotive, and medical all have strong mixed-signal elements in their semiconductor content value proposition. What is critical to recognize is that many of the design techniques that were initially driven by advanced-node programs have merit across the spectrum of active semiconductor process technologies. For example, digitally controlled, calibrated, and compensated analog IP, along with power-reducing mutli-supply domains, power shut-off, and state retention are being applied in many programs on “legacy” nodes.

Another graph from IBS shows that the design starts at 45nm and below will continue to grow at a healthy pace.  The data also shows that nodes from 65nm and larger will continue to comprise a strong majority of the overall starts. 

Figure 2.  IBS: Design starts per process node

TSMC made a comprehensive announcement in September related to “wearables” and the Internet of Things. From their press release:

TSMC’s ultra-low power process lineup expands from the existing 0.18-micron extremely low leakage (0.18eLL) and 90-nanometer ultra low leakage (90uLL) nodes, and 16-nanometer FinFET technology, to new offerings of 55-nanometer ultra-low power (55ULP), 40ULP and 28ULP, which support processing speeds of up to 1.2GHz. The wide spectrum of ultra-low power processes from 0.18-micron to 16-nanometer FinFET is ideally suited for a variety of smart and power-efficient applications in the IoT and wearable device markets. Radio frequency and embedded Flash memory capabilities are also available in 0.18um to 40nm ultra-low power technologies, enabling system level integration for smaller form factors as well as facilitating wireless connections among IoT products.

Compared with their previous low-power generations, TSMC’s ultra-low power processes can further reduce operating voltages by 20% to 30% to lower both active power and standby power consumption and enable significant increases in battery life—by 2X to 10X—when much smaller batteries are demanded in IoT/wearable applications.

The focus on power is quite evident and this means that all of the power management and reduction techniques used in advanced node designs will be coming to legacy nodes soon.

Integration and miniaturization are being pursued from the system-level in, as well as from the process side. Techniques for power reduction and system energy efficiency are central to innovations under way.  For mixed-signal program teams, this means there is an added dimension of complexity in the verification task. If this dimension is not methodologically addressed, the level of risk adds a new dimension as well.

Reason 3: Trends are pushing the limits of established design practices

Risk is the bane of every engineer, but without risk there is no progress. And, sometimes the amount of risk is not something that can be controlled. Figure 3 shows some of the forces at work that cause design teams to undertake more risk than they would ideally like. With price and form factor as primary value elements in many growing markets, integration of analog front-end (AFE) with digital processing is becoming commonplace.  

Figure 3.  Trends pushing mixed-signal out of equilibrium

The move to the sweet spot of manufacturing at 28nm enables more integration, while providing excellent power and performance parameters with the best cost per transistor. Variation becomes great and harder to control. For analog design, this means more digital assistance for calibration and compensation. For greatest flexibility and resiliency, many will opt for embedding a microcontroller to perform the analog control functions in software. Finally, the first wave of leaders have already crossed the methodology bridge into true mixed-signal design and verification; those who do not follow are destined to fall farther behind.

Reason 4: The tipping point accelerants are catching fire

The factors cited in Reason 3 all have a technical grounding that serves to create pain in the chip-development process. The more factors that are present, the harder it is to ignore the pain and get the treatment relief  afforded by adopting known best practices for truly mixed-signal design (versus divide and conquer along analog and digital lines design).

In the past design performance was measured in MHz with simple static timing and power analysis. Design flows were conveniently partitioned, literally and figuratively, along analog and digital boundaries. Today, however, there are gigahertz digital signals that interact at the package and board level in analog-like ways. New, dynamic power analysis methods enabled by advanced library characterization must be melded into new design flows. These flows comprehend the growing amount of feedback between analog and digital functions that are becoming so interlocked as to be inseparable. This interlock necessitates design flows that include metrics-driven and software-driven testbenches, cross fabric analysis, electrically aware design, and database interoperability across analog and digital design environments.

Figure 4.  Tipping point indicators

Energy efficiency is a universal driver at this point.  Be it cost of ownership in the data center or battery life in a cell phone or wearable device, using less power creates more value in end products. However, layering multiple energy management and optimization techniques on top of complex mixed-signal designs adds yet more complexity demanding adoption of “modern” mixed-signal design practices.

Reason 5: Convergence of analog and digital design

Divide and conquer is always a powerful tool for complexity management.  However, as the number of interactions across the divide increase, the sub-optimality of those frontiers becomes more evident. Convergence is the name of the game.  Just as analog and digital elements of chips are converging, so will the industry practices associated with dealing with the converged world.

Figure 5. Convergence drivers

Truly mixed-signal design is a discipline that unites the analog and digital domains. That means that there is a common/shared data set (versus forcing a single cockpit or user model on everyone). 

In verification the modern saying is “start with the end in mind”. That means creating a formal approach to the plan of what will be test, how it will be tested, and metrics for success of the tests. Organizing the mechanics of testbench development using the Unified Verification Methodology (UVM) has proven benefits. The mixed-signal elements of SoC verification are not exempted from those benefits.

Competition is growing more fierce in the world for semiconductor design teams. Not being equipped with the best-known practices creates a competitive deficit that is hard to overcome with just hard work. As the landscape of IC content drives to a more energy-efficient mixed-signal nature, the mounting risk posed by old methodologies may cause causalities in the coming year. Better to move forward with haste and create a position of strength from which differentiation and excellence in execution can be forged.

Summary

2015 is going to be a banner year for mixed-signal design and verification methodologies. Those that have forged ahead are in a position of execution advantage. Those that have not will be scrambling to catch up, but with the benefits of following a path that has been proven by many market leaders.

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

Analog and Mixed-signal (AMS) designs are increasingly using active power management to minimize power consumption. Typical mixed-signal design uses several power domains and operate in a dozen or more power modes including multiple functional, standby and test modes. To save power, parts of design not active in a mode are shut down or may operate at reduced supply voltage when high performance is not required. These and other low power techniques are applied on both analog and digital parts of the design. Digital designers capture power intent in standard formats like Common Power Format (CPF), IEEE1801 (aka Unified Power Format or UPF) or Liberty and apply it top-down throughout design, verification and implementation flows. Analog parts are often designed bottom-up in schematic without upfront defined power intent. Verifying that low power intent is implemented correctly in mixed-signal design is very challenging. If not discovered early, errors like wrongly connected power nets, missing level shifters or isolations cells can cause costly rework or even silicon re-spin. 

Mixed-signal designers rely on simulation for functional verification. Although still necessary for electrical and performance verification, running simulation on so many power modes is not an effective verification method to discover low power errors. It would be nice to augment simulation with formal low power verification but a specification of power intent for analog/mixed-signal blocs is missing. So how do we obtain it? Can we “extract” it from already built analog circuit? Fortunately, yes we can, and we will describe an automated way to do so!

Virtuoso Power Manager is new tool released in the Virtuoso IC6.1.8 platform which is capable of managing power intent in an Analog/MS design which is captured in Virtuoso Schematic Editor. In setup phase, the user identifies power and ground nets and registers special devices like level shifters and isolation cells. The user has the option to import power intent into IEEE1801 format, applicable for top level or any of the blocks in design. Virtuoso Power Manager uses this information to traverse the schematic and extract complete power intent for the entire design. In the final stage, Virtuoso Power Manager exports the power intent in IEEE1801 format as an input to the formal verification tool (Cadence Conformal-LP) for static verification of power intent.

Cadence and Infineon have been collaborating on the requirements and validation of the Virtuoso Power Manager tool and Low Power verification solution on real designs. A summary of collaboration results were presented at the DVCon conference in Munich, in October of 2018.  Please look for the paper in the conference proceedings for more details. Alternately, can view our Cadence webinar on Verifying Low-Power Intent in Mixed-Signal Design Using Formal Method for more information.

Do you want to create designs that are correct by construction? Read along this blog to understand how you can achieve this by using Width Spacing Patterns (WSPs) in your designs. WSPs, are track lines that provide guidance for quickly creating wires. Defining WSPs that capture the width-dependent spacing rules, and snapping the pathSegs of a wire to them, ensures that the wires meet width-dependent spacing rules.(read more)