TOPIC : Introduction to TOPIC : Introduction to Functional ModelingFunctional Modeling

UNIT 1: Modeling Digital Circuits

Module 1 : Functional Modeling

Contents of the moduleContents of the module Introduction to functional modeling Different Functional Models

◦ Truth table◦ Primitive cube◦ Binary Decision Diagram◦ Programming model◦ RTL model

Functional Model Functional Model IntroductionIntroduction A functional model of a digital system is a

representation of its logic function. Any digital system can be represented by a black

box which processes the input to produce its output.

The value of the outputs vary with inputs and a certain delay exists

The logic function is the input-output mapping that deals with the value transformation.

Functional modelingFunctional modeling Tells the relationship between input and output

values of a circuit. It does not talk about any timing aspect. Simulation implies calculation of the output

(response) of a circuit. Functional models provide the information for

simulation. It can be done at two levels

◦ Logic level ◦ RTL(program) level

Different Functional Different Functional ModelsModels Logic Level

◦ Truth tables ◦ Primitive cubes◦ Binary decision diagrams

RTL Level◦ Programming model◦ RTL model