# lec11a - Lecture 11alt Advances in Combinational ATPG...

This preview shows pages 1–6. Sign up to view the full content.

Copyright 2001, Agrawa VLSI Test: Lecture 11alt 1 Lecture 11alt Advances in Combinational ATPG Algorithms Branch and Bound Search FAN – Multiple Backtrace, head lines (1983) TOPS – Dominators (1987) SOCRATES – Learning (1988) EST – Search space learning (1991) ATPG Performance improvements Summary

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Copyright 2001, Agrawa VLSI Test: Lecture 11alt 2 ATPG: A Boolean Satisfiability Problem CUT CUT with fault f(a,b,c) = 1 Test Vector (a,b,c)
Copyright 2001, Agrawa VLSI Test: Lecture 11alt 3 SAT is NP-Complete a c c b b 1 1 1 0 0 0 0 0 c c 0 1 f a b c f Binary Decision Diagram (BDD)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Copyright 2001, Agrawa VLSI Test: Lecture 11alt 4 Search for a Solution Problem: Given a value of a Boolean function of binary variables, find values of the variables. Solution: Starting at the root, enumerative traversal of the binary decision diagram (BDD) until a solution is found. BDD is a search tree – search consists of Branch : Set an untried value for a variable Backtrack to previous branching point if there is no untried value Stop if solution found, or backtracked to root without untried values Or, bound search tree for future traversals if solution is impossible and backtrack to previous branching point (some variable orderings may lead to early bounding) Or, continue
Copyright 2001, Agrawa VLSI Test: Lecture 11alt 5 Example: f = 1 a c c b b 1 1 1 0 0 0 0 0 c c 0 1 f a b c f Binary Decision Diagram (BDD) bound

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 09/16/2011 for the course ELEC 7250 taught by Professor Agrawal during the Summer '11 term at Auburn University.

### Page1 / 23

lec11a - Lecture 11alt Advances in Combinational ATPG...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online