Thursday, December 11, 2008

Testbench Methodology

Let us have a look on testbench[TB] methodology in this posting. We all know that reusable verification IPs is the key thing that reduces the verification effort and time, especially for the SoCs. One has to make sure that these VIPs are created as per some good TB methodology. Generally EDA vendors provide these methodologies to enable their customers to create powerful TBs easily.

Why you need testbench methodology?

TB methodology defines the architecture of the verification environment, suggests appropriate language constructs, defines coding guidelines and gives comfort by adding the debugging utilities and application packages on top of base class library. So the TB methodology helps you to quickly realize the powerful and highly reusable testbench and verify your design thoroughly.

As a non EDA guy, I would say TB methodology is mainly for making your TB highly reusable by providing cleaner architecture and interface. It should focus more on suggesting the powerful HVL constructs and coding guidelines to create the verification environment.

Verification engineers have complete freedom to choose the HVL and methodology for their TBs. One can also create his own base class library and define methodology that suits for his design and organizational needs. For example, if you are selling your IPs to different customers who use multiple simulators, you need to make sure that your VIP/TB runs on all the simulators, especially when you choose the HVLs like SV. In this case it's better to create a base class library that runs on all or at least on the required simulators.

But creating base class and defining your own methodology is not an easy job. It should be planned very carefully by considering the business value and demand. It requires lot of effort, your precious time, valuable resources and huge investment. In addition to all these burdens you need to provide support for your base class library. Very rarely, some big organizations, especially product developers create their own base class and methodology to meet their long term business demands.

If you are working in the start-up or services organizations and if your product TTM is very critical, you need to plan for close working partnership with a reliable EDA vendor that provides matured TB methodology and good verification consultancy services that can guide you technically well to achieve your verification goals.