Posts Tagged ‘Assertions’

7 May, 2014

My Feb. 4 post introduced Mentor Graphics’ three-step FPGA verification process intended to help design teams get out of the reprogrammable lab more effectively. Since then, I’ve engaged FPGA vendors, design managers and engineers to explain the process, paying special attention to the merits and technical detail for injecting automation into any FPGA verification environment, the hallmark of Mentor’s process. The feedback from these conversations helped me to develop a series of technical webinars, now available for free and on-demand. Check them out and let us know what you think in the comments below. My hope is the webinars might serve as a starting point for your own conversations on verification of FPGAs, demand for which seems to continue to grow as process nodes shrink.

Injecting Automation into Verification – FPGA Market Trends

Injecting Automation into Verification – Code Coverage

Injecting Automation into Verification – Assertions

Injecting Automation into Verification – Improved Throughput

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4 February, 2014

Marketing teams at FPGA vendors have been busy as the silicon nanometer geometry race escalates. Altera is “delivering the unimaginable” while Xilinx is offering “all programmable SoCs” to design centers. It’s clear that the SoC has become more accessible to a broader market today and that FPGA vendors have staked out a solid technology roadmap for the near future. Do marketing messages surrounding the geometry race effect day to day life of engineers, and if so, how – especially when it comes to verification?
An excellent whitepaper from Altera, “The Breakthrough Advantage for FPGAs with Tri-Gate Technology,” covers Altera’s Stratix 10 FPGAs and SoCs. The paper describes verification challenges in this new expanded market this way: “Although current generation FPGAs require a rigorous simulation verification methodology rivaling ASICs, the additional lab testing and ability to reprogram FPGAs save substantial manpower investment. The overall cost of ownership must be considered when comparing an FPGA whose component price is higher than an ASIC of similar complexity.” I believe you can use this statement to engage your management in a discussion about better verification processes.

Xilinx also has excellent published technical resources. Its recent UltraScale backgrounder describes how they are solving the challenges in implementing a design with their reprogrammable silicon. Clearly Xilinx has made an impressive investment to make it easier to implement a design with its FPGA UltraScale products. Improvements include ASIC-like clocking and annealing dataflow bottlenecks without compromising performance. Xilinx also describes improvements when using its Vivado design suite, particularly when it comes to in-lab design bring up.

For other FPGA insights, it’s also worth checking out Electronics Engineering Journal’s recent article “Proliferating Programmability in 2014,” which claims that the long-term future of FPGAs tool flows even though, as Kevin Morris sees it, EDA seems to have abandoned the market. (Kevin, I’m here to tell you you’re wrong.)

Do you think it’s inevitable that your FPGA team will first struggle to make it across the verification finish line before adopting a more process-oriented verification flow like the ASIC market demands? It’s not. I base this conclusion on the many conversations I’ve had with FPGA designers, their managers, sales engineers and many other talented people in this market over the years. Yes, there are significant challenges in FPGA design, but not all of them are technology related. With some emotion, one engineer remarked that debugging the same type of issue over and over in the hardware lab and expecting a different outcome was insane. (He’s right.) Others say they need specific ROI information for their management to even accept their need for change. Still others state that had they only known the solutions I talked about in my seminar a year ago, they would have not spent months and months bringing up their design in the lab.
With my peers here at Mentor Graphics, I have developed a three-step verification flow that includes coverage, assertions and improved throughput. I’ll write about this flow and related issues in the weeks ahead here on this blog. The flow is built on fundamental verification technologies that benefit the broad FPGA market. The goal, in developing the technology and writing about it here, has been to provide practical solutions and help more FPGA teams cross the verification gap.

In the meantime, what are your stories? Are you able to influence your management into adopting advanced technology to aid lab bring-up? Is your management’s bias towards lower cost and faster implementation (at the expense of verification)? Let me know in the comments or, if you prefer, by e-mail:

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5 December, 2012

IEEE Std. 1800™-2012 Officially Ratified

The IEEE Standards Association (SA) Standards Board (SASB) officially approved the latest SystemVerilog revision, Draft 6, as an IEEE standard.  The SASB Review Committee (RevCom) agenda and the SASB agenda include review and formal approval of the latest work by the IEEE Computer Society Design Automation Standards Committee’s (DASC) SystemVerilog Working Group at their December 2012 meeting series.

What’s New?

The new standard has many new features, numerous clarifications and various corrections to improve the standard and keep pace with electronic system design and verification.  DVCon 2012 included a session presentation, Keeping Up with Chip – The Proposed SystemVerilog 2012 Standard Makes Verifying Ever-Increasing Design Complexity More Efficient” that detailed the standard.  The paper was written by Stuart Sutherland (Sutherland HDL, Inc.) and Tom Fitzpatrick (Mentor Graphics).  You can find a copy of the paper here at the DVCon 2012 archive and the presentation can be found at Sutherland HDL’s site here.

For users of Mentor Graphics’ Questa Verification Platform, many of the major SystemVerilog 2012 features can be used today, like multiple inheritance.  As Stu and Tom said in their presentation, “This is BIG!”  If you read their full paper, they discuss some ways this new feature might be useful for a UVM testbench.

Major work was done to augment the current notion of constraints in SystemVerilog.  In past versions of the standard they were known as hard constraints.  What this meant was all the conditions of the constraints had to be met otherwise there would be an error.  There was no built-in method to relax the need to satisfy the constraints.  Given the world of multiple constraints is the norm for testbenches today the potential for conflicts between them is high.  To alleviate this the SystemVerilog Working Group introduced soft constraints to the standard.  If you are interested in the details of what was proposed to be added the standard, you can reference the full proposal here that is included in the standard.  Stu and Tom said that “This is also a big enhancement!”


IEEE 1800™-2012 has only now been approved.  The standard itself is not ready to be published yet.  Plans are to have it ready to be published before DVCon 2013, which is scheduled for late February 2013.  I will  share publication information as it becomes available.  And, I hope you join me and attend DVCon 2013 where we can plan to celebrate the unveiling of the published standard.

sva3rdE_cover-wsWhile the IEEE publication will be the authoritative source on the standard, I have pointed to the presentation and paper by Stu Sutherland and Tom Fitzpatrick for information on the new standard that you can reference now.  For those who depend on assertions, you will find SystemVerilog-2012 has a major update with enhancements for properties and sequences in the area of immediate assertions, data type support, argument passing, vacuity definitions, global clock resolution and inferred clocking in sequences and much more.  You may find the SystemVerilog Assertions Handbook 3rd Edition by Ben Cohen, et. al. to be of value as well.  You can find more information about it on here.

The Story Continues…

There is much more to the SystemVerilog-2012 story I will share more of that in the months ahead.  The global team of experts who have put this together has been an outstanding collection of individuals ranging from producers and suppliers of electronic design automation software to consumers of said technology who have ensured the language can be used to design and verify the most demanding of electronic systems.

Stay tuned!  For now, I encourage you to get informed!

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