Verification Plan & Levels of Verification

1. Verification Plan & Levels of Verification • The Verification Plan • Yesterdays and today’s design environment • Design specification document • Verification success • Levels of verification EE694v-Verification-Lect7

2. The Verification Plan • Just as a design meets a specification, the verification plan is the specification for the verification effort. • Defines • What is success • How a design is to be verified • Functional correctness • Which testbenches to write • Schedule for verification effort EE694v-Verification-Lect7

3. In The Past • Verification was left to each designer to do as they wished • Verification was done as time allowed • Emphasis was “does chip work?” • Have progressed from “does chip work?” to • Does chip work in the system? • Does chip work in the system as specified? • Does the system work as specified? EE694v-Verification-Lect7

4. Today’s Environment • Wish to have system integration go smoothly • Simulate chip(s) in system environment to identify problems early, preferably during design and prior to fabrication • Tools, if effectively used, can help • Simulation • Linting • Other tools EE694v-Verification-Lect7

5. Specifying the Verification • When will verification of design be completed to the required degree of confidence • Must determine • How much work verification will require • How many people are needed for the verification effort • How long will the verification effort take EE694v-Verification-Lect7

6. Design Specification Document • Verification effort relies on a complete specification document • Must be a written document • Is the common source for both the design’s implementation and its verification • When design’s output is not as expected this document helps determine whether the design is correct (verification in error) or not (verification correct) EE694v-Verification-Lect7

7. The Plan & 1st Time Success • The verification plan defines what success is • Insures all essential features of design are appropriately verified • Documents which features are essential and which are optional • Not all features of the final design need be included in defining 1st time success • Final success requires that all features in the final design are working and verified so. EE694v-Verification-Lect7

8. Levels of Verification • As the level of focus changes, what is being verified changes also • The level of granularity is also included in the plan • Best partitions to verify are those where controlability and observability are best • Partitions being verified must have relatively stable functionality and interfaces EE694v-Verification-Lect7

9. Unit-Level Verification • Design units are logical partitions and vary from small to large, simple to complex • Small/Simple - FIFO, small state machine • Large/Complex - PCI slave interface, DSP datapath • Often have interfaces that are not fixed and firm • Often functionality is not yet fixed and firm • Any reasonable size project will have a large number of design units • Verification of the entire design at this level would probably be too time consuming EE694v-Verification-Lect7

10. Reusable Component Verification • Component is designed to its own specification • Component intended to be used as-is in many different designs • Typically the component implements a common function or allows connection to a standardized interface • Component is used in many designs - focus is on its functionality • Potential users must have confidence that design is indeed correct EE694v-Verification-Lect7

11. ASIC & FPGA Verification • These units form a physical and possibly a logical partition • Often have their own specification • Often contain a collection of independently designed and verified components • Todays ASICs and FPGAs are too complex to verify and debug during integration. Need verification for them prior to synthesis or downloading the programming. EE694v-Verification-Lect7

12. System-Level Verification • There are many definitions for a system!!! • In the book - “a system is a logical partition composed of independently verified components.” • System could be • composed of a few reusable components • a subset of an SoC ASIC • ASICs (or part of ASICs) on different boards • Focuses on interaction between components • Relies on individual components being functionally correct EE694v-Verification-Lect7

13. Board-Level Verification • Confirm that component connectivity is correct • Some components on boards, such as capacitors, do not translate easily to digital domain • Depending on the complexity level, could be used to verify functionality (as with any other level) • Must make sure what is verified is what is manufactured (as with all levels) EE694v-Verification-Lect7