cellular automata as a test pattern generator and output response compactor for bist

ECE-DEPARTMENT

1. SHIVA SHANKER BEERAVELLI : 10T81A04482. PALUSA KRANTHI KUMAR GOUD : 10T81A04173. G.SHIVA NARAYANA REDDY : 10T81A04494. SHEELAM RAMU : 10T81A0431

Internal Guide: Mr.K.ASHOK KUMAR

Assoc. Prof & HOD-ECE

A MINI-PROJECT ON

IMPLEMENTATION OF HYBRID CELLULAR AUTOMATA AS A TEST

PATTERN GENERATER & RESPONSE COMPACTOR FOR BIST

CONTENTS:

Objective

Working Principles

Diagrammatic View

Advantages /Disadvantages With Examples

Applications in Real Time Scenario

Future Extension of the Project

Summary

References /Bibliography

WHY TESTING IS IMPORTANT IN VLSI DESIGN ?

Specifications Code designing Code verification RTL designing Simulation Synthesis Fabrication

TESTING packing

PROBLEM:Testing of circuits in past was done

by ATE

PRESENT APPROACH FOR TESTING: (DFT-DESIGN FOR TESTABILITY)

BUILT-IN-SELF TEST BIST eliminating the dependence on an external

automated test equipment (ATE)

Block Diagram shows TESTING ProcessSeed value

Seed value

din

Good/fault

MAIN OBJECTIVE:

To construct the TPG

To construct the ORA

Using CELLULAR AUTOMATA (CA)

Pseudo random generator

CELLULAR AUTOMATA:

Cellular automata is collection of cells with regular collections.

Working Principles/Rules:

Each cell connects to its local neighbors by using rule 90 and rule150.

Flip-flops

Rule 90: Rule 150:

Transition function [rule 90] : Xc(t+1) = Xc-1(t) xor Xc+1(t). Transition function [rule 150]: Xc(t+1) = Xc-1(t) xor Xc(t) xor Xc+1(t). 

C-1 : pastC : presentC+1 : future

Diagrammatic View:

Cellular automata as a TEST PATTERN GENERATER :

CA produces (2^n-1) test patterns automatically.

Cellular automata as a RESPONSE COMPACTOR:

din din

din

din

din

Lower cost of test, since the need for external electrical testing using an ATE will be reduced, if not eliminated.

better fault coverage, since special test structures can be incorporated onto the chips.

easier customer support.

capability to perform tests outside the production electrical testing environment.

Shorter test times if the BIST can be designed to test more structures in parallel.

Advantages:

additional silicon area and fob processing requirements .

additional pin requirements.(since the BIST circuitry need a way to

interface with the outside world to be effective)

possibly bigger package size

Disadvantages:

Integrated circuit manufacture :BIST is used to make faster, less-expensive integrated circuit manufacturing tests.

Computers(pc’s test itself at startup)

Medicine (medical devices test themselves to assure continued safety )

Military (used in missiles where the bist is computer c controlled)

Applications in Real Time Scenario :

Future Extension of the Project:

•Built-In Self-Repair (BISR).

•Transparent BIST for RAMs.

•Programmable memory BIST.

References /Bibliography:

1. Bushnell and Agrawal, “Essentials of Electronic Testing for Digital, Memory & Mixed-Signal VLSI Circuits” New York: Kluwer Academic Publishers, 2002

2. Serra, M.; Slater, T.; Muzio, J.C.; Miller, D.M., “The analysis of one-dimensional linear cellular automata and their aliasing properties, IEEE Transactions on, Volume: 9 , Issue: 7 , July 1999, Pages:767 – 778.

3. Jianbing Zhao., “A Novel FPGA Manufacture-oriented Interconnect Fault Test,” 9th International Conference on Solid-State and Integrated-Circuit Technology, 2008