EE694v-Verification-Lect7-1- Verification Plan & Levels of Verification The Verification Plan Yesterdays and today’s design environment Design specification

EE694v-Verification-Lect7 -1-

Verification Plan & Levels of Verification

• The Verification Plan• Yesterdays and today’s design environment• Design specification document• Verification success• Levels of verification


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


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?


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


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


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)


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.


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


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


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


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.


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


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)