Boosted confidence in new tool revisions for synthesis and place & route. With massively parallel architecture and adaptive proof technology, the Conformal Smart LEC delivers dramatic turnaround time improvements in equivalence checking by over 20X for RTL-to-gate comparisons. The remaining are single bit flops. Here, we can see the connection of reported net in the LEC fail design. The reason behind is that many paths which are going through one failed/broken connection – and hence all its endpoints (compare points) – are reported “Non-equivalent”. The Conformal Smart Logic Equivalence Checker (LEC) is the next-generation equivalency checking solution. © 2020 Cadence Design Systems, Inc. All Rights Reserved. Watch how to easily tackle complex and cutting edge designs. We are considering Conformal tool as a reference for the purpose of explaining the importance of LEC. Clock gating cells not getting mapped after cloning in revised netlist. css: '', You will get an email to confirm your subscription. Now, if we rerun the LEC it will pass and non-equivalent report will show zero non-equivalent points. An open IP platform for you to customize your app-driven SoC design. While checking, we can easily note that the reported net is connected to one inverter which is missing in the LEC fail database. Driving efficiency and accuracy in advanced packaging, system planning, and multi-fabric interoperability, Cadence® package implementation products deliver the automation and accuracy. Now, we need to find the actual net connection of this net in the previous LEC pass database. In the transition from setup mode to LEC mode, the Conformal tool flattens and models the golden and revised designs and automatically maps the key points. For the execution of LEC, the Conformal tool requires three types of files. As it can be seen in Fig-2, once we check this net (BUFT_net_362908) connection in LEC fail database, we see that it is connected only to the input pins of other cell (*_364714/A), but the other connection (driver side) of this net is missing due to unintentional cell deletion. The key points that the Conformal tool does not map are classified as unmapped points. .lec file guide the Conformal tool to execute different command in a systematic way. This paper gives an introduction of logical equivalence check, flow setup, steps to debug it, and solutions to fix LEC. Whereas 152 flops reported in non-equivalent file in LEC fail database are same as fanout of net (BUFT_net_362908) reported in LEC pass database. The Conformal tool employs two name-based methods and one no-name method to map key points. Achieve best PPA with the next-generation Digital Full Flow solution, Address digital implementation challenges with machine learning, Solve analog simulation challenges in complex designs, See how the Virtuoso Design Platform addresses advanced custom IC and system design challenges, Prototype your embedded software development, Learn how early firmware development enabled first silicon success at Toshiba Memory, Solve the challenges of long-reach signaling with Cadence 112G SerDes IP, Meeting the needs of 5G communication with Tensilica, Cadence Design Solutions certified for TSMC SoIC advanced 3D chip stacking technology, Four reasons to avoid multi-layer flip-chip pin padstacks, See how to improve electrical-thermal co-simulation with the Celsius™ Thermal Solver, Get true 3D system analysis with faster speeds, more capacity, and integration. formId: '65027824-d999-45fc-b4e3-4e3634775a8c' The Conformal EC-XL configuration provides formal equivalence checking for digital logic, including complex arithmetic logic and datapaths. Use truth tables to establish these logical equivalences. Logical connectivity breaks during timing fixing or while doing manual ECO. This paper presents why LEC (Logical Equivalence Check) is important in the ASIC design cycle, how to check it, and what to do when LEC is failing. .scan_const file provides scan related constraints like if we want to ignore some scan connections/serdes input/output pins which are defined in this file. How to Obtain Google’s GMS Certification for Latest Android Devices? By default, it automatically maps key points with the name-first mapping method when it exits the setup mode. Please confirm to enroll for subscription! This paper gives an introduction of logical equivalence check, flow setup, steps to debug it, and solutions to fix LEC. Natural deduction proof editor and checker This is a demo of a proof checker for Fitch-style natural deduction systems found in many popular introductory logic textbooks. 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Learn why signal integrity analysis needs to be power-aware, See how our customers create innovative products with Cadence, Learn how Intelligent System Design™ powers future technologies, Join Cadence technology users, developers, and industry experts for networking and sharing best practices, Exhaustively verifies multi-million–gate ASICs several times faster than traditional gate-level simulation, Decreases the risk of missing critical bugs with independent verification technology, Enables faster, more accurate bug detection and correction throughout the entire design flow, Extends equivalence checking capability to complex datapaths and closes the RTL-to-layout verification gap (XL configuration), Ensures RTL models perform the same functions as the corresponding transistor circuits implemented on silicon (GXL configuration), Advanced adaptive proof algorithms and massively parallel architecture for RTL-to-layout verification dramatically improves runtime (Smart LEC). This file shows the unmapped nets where the logical connectivity is broken. Many EDA companies provide tools to do the check. We designate the design types, which are Golden (synthesized netlist) and Revised (generally, the revised design is the modified or post-processed design that the Conformal tool compares to the Golden design). Learn more Conformal EC There are various EDA tools for performing LEC, such as Synopsys Formality and Cadence Conformal. As designs continue to get more complicated in order to meet aggressive requirements for power, performance, area, and time to market, the formal verification of the designs continues to be a staple and must-have signoff metric to ensure silicon success. Formal equivalence checking process is a part of electronic design automation (EDA), commonly used during the development of digital integrated circuits, to formally prove that two representations of a circuit design exhibit exactly the same behavior. It is not uncommon for teams to encounter logical equivalence check (LEC) failure. Trusted, independent formal verification technology for fast, accurate bug detection and correction. The Conformal Equivalence Checker (EC) offers the industry’s only complete equivalence checking solution for verifying the widest variety of circuits. Decreased risk of missing bugs inserted by the back-end process. Cadence® Conformal® Logic Equivalence Checking Solutions provide formal equivalence checking of designs from RTL to P&R. With shrinking technology nodes and increasing complexity, logical equivalence check plays a major role in ensuring the correctness of the functionality. Multiple reports are generated once LEC is completed: At the time of sign-off or tapeout phase, the schedule is too tight to handle blocks with some critical logical failure. .stdlib file contains pointer of standard cells library. These 152 flip-flops reported as non-equivalent are the multibit flops. hands-on exercise 2.5.2. The comparison determines if the compared points are: In the case of aborted compare points, we can change the compare effort to a higher setting. Thus, the Conformal tool can continue the comparison on only the aborted compare points. This is why LEC is one of the most important checks in the entire chip design process. In the above image, we can see that one net (BUFT_net_362908) is not mapped in the design. p ⇒ q ≡ ¯ q ⇒ ¯ p. p ∨ p ≡ p. p ∧ q ≡ ¯ ¯ p ∨ ¯ q. p ⇔ q ≡ (p ⇒ q) ∧ (q ⇒ p) Answer. Also, the chances of breaking logical connectivity are high, when you get the functional ECO and do the manual connection. Front-end covers the architectural specifications, coding and verification, whereas back-end involves the physical implementation of the design on the targeted technology node. Using a real-world scenario, it also showcases the reports generated after LEC completion and suggests an easy way to find out the root cause of LEC failure. The Conformal EC-GXL configuration provides formal equivalence checking for custom circuits including memories. Unmapped points are classified into three categories: After the Conformal tool maps the key points, the next step of the verification is comparison. Medical Device Design and Development: A Guide for Medtech Professionals, Everything You Need to Know About In-Vehicle Infotainment Systems, Everything you Need to Know About Hardware Requirements for Machine Learning. At every stage, we need to make sure that the logical functionality is intact and does not break because of any of the automated or manual changes. Cadence® digital design and signoff solutions provide a fast path to design closure and better predictability, helping you meet your power, performance, and area (PPA) targets. Unreachable unmapped points are key points that do not have an observable point, such as a primary output. Solve your complexity of logical equivalence check in ASIC design cycle, For all career related inquiries, kindly visit our careers page or write to careers@einfochips.com. Conversely, the no-name-mapping method is useful when the Conformal tool must map designs with completely different names. The first step is to check the non-equivalent file. Cadence® system design and verification solutions, integrated under our Verification Suite, provide the simulation, acceleration, emulation, and management capabilities. The chances of a logical breakdown will be high at the tapeout phase where the physical design engineer does not have much time for block closure. This is a really trivial example. Logical equivalence is different from material equivalence, although the two concepts are intrinsically related. 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