Verification Methodologies: A Comparison between UVM and OVM for ASIC Verification

  • January 10, 2024

    author: Ramya

When working in the field of ASIC (Application-Specific Integrated Circuit) verification, selecting an effective verification methodology is absolutely necessary to assure the dependability and functionality of complicated designs. Both the Universal Verification Methodology (UVM) and the Open Verification Methodology (OVM) have quickly become two of the most extensively used verification approaches in the business world. This article's purpose is to provide a complete comparison of UVM and OVM by pointing out their parallels and differences as well as their respective advantages and disadvantages. ASIC verification engineers are able to make educated selections that will allow them to maximize the effectiveness of their verification efforts when they have a thorough understanding of the characteristics and capabilities of each technique.



An introduction to UVM:


The Universal Verification technique, sometimes known as UVM, is a verification technique that has been standardized and is based on the IEEE 1800 standard for SystemVerilog. It offers a framework for the construction of verification environments that are modular, reusable, and scalable. In order to model and administer the verification components, UVM encourages the usage of techniques from object-oriented programming, also known as OOP. The utilization of layered architecture, the modeling of transactions at a lower level, the development of constrained-random stimuli, and the collection of functional coverage are some of the key elements of UVM. UVM provides users with access to a vast collection of pre-defined classes and libraries, hence cutting down on the amount of time and effort needed to construct verification environments.


An introduction to OVM :


The Open Verification Methodology, sometimes known as OVM, is an open-source verification methodology that was developed by a coalition of different organizations, including Cadence Design Systems and Mentor Graphics. The Open Verification Method (OVM) is an updated version of the previous Verification Methodology Manual (VMM) that offers a thorough framework for the construction of reusable verification components. In a manner analogous to that of UVM, OVM makes advantage of the OOP capabilities of SystemVerilog and promotes the development of constrained-random stimulus and the gathering of functional coverage. OVM places a strong emphasis on the idea of "reusable verification intellectual property" (VIP), which enables engineers to use previously developed verification components in a variety of different projects.


Comparative characteristics of UVM and OVM 


As a result of their shared evolutionary history, UVM and OVM exhibit a number of similarities in their physiology and behavior. Both of these approaches are based on the IEEE 1800 SystemVerilog standard and incorporate OOP ideas in order to produce verification environments that are both modular and reusable. Both of these approaches make use of methodologies for the production of constrained-random stimuli in order to rapidly investigate the design space and locate edge-case circumstances. In addition, UVM and OVM both include means for gathering statistics on functional coverage, which can be used to evaluate how complete the verification is.


A comparison of UVM and OVM's differences


There are a number of key distinctions that separate UVM and OVM, despite the fact that they have many similarities. The difference in their source code is one of the most important aspects. OVM is an open-source approach that needs further setup and installation, whereas UVM is based on SystemVerilog libraries that are given by Accellera. This distinction has an effect on how easy it is to adopt and on the resources that are available.


Another important distinction is the degree of support provided and the amount of industry adoption. The use of UVM as the industry standard for ASIC verification has garnered widespread approval and established itself as a de facto industry standard. It has the advantage of having a sizable user community, a substantial amount of documentation, and a multitude of third-party vendor offers. Even while OVM is still utilized by some businesses, its popularity has been on the decline over the past few years.


In addition, in comparison to OVM, UVM provides enhanced and better capabilities and advancements. For instance, UVM has built-in support for transaction-level modeling (TLM), which makes it easier to verify designs that contain complicated communication protocols. Additionally, UVM gives users access to a standardized register model, which makes the process of verifying control and status registers in ASIC designs much easier.


In addition, UVM possesses a number of extra features that OVM does not have, such as greater reporting and messaging capabilities, standardized setup procedures, and improved error handling. UVM is an improvement over OVM in this regard. These features contribute to greater debugging and analysis capabilities, which in turn reduces the amount of time needed to detect and resolve issues while the verification process is being carried out.


Concluding 


To summarize, both UVM and OVM are effective verification approaches that may be applied to ASIC designs. UVM has emerged as the preferred choice due to its improved features, widespread industry acceptance, and extensive support from the verification community. Despite the fact that they share common principles and concepts, UVM has emerged as the preferred choice. A broad user base, availability of pre-defined libraries, and conformance to industry standards make UVM an appealing choice for ASIC verification engineers. However, for those who are currently adopting OVM, it may still serve as a viable choice. This is particularly true for legacy projects or enterprises that have invested extensively in OVM-based verification environments. In the end, the decision between UVM and OVM should be determined by the particular requirements of the project, the resources that are readily available, as well as the amount of support and experience that exists inside the business.