Saturday, September 23, 2023

VLSI Test Principles and Architectures: Design for Testability


VLSI Test Principles and Architectures: Design for Testability by L.T Wang, C W Wu and X Q Wen

 miter circuit used for combinatorial equivalence checking

Test Principles

" testing can be viewed as a design moving through different abstraction levels"

"select specific test patterns based on circuit structural information and a set of fault models. This approach is called structural testing"

 "fault models are needed for fault simulation as well as for test generation."

Fault Modeling - Equivalent faults and fault collapsing

Essentials of Electronic Testing for Digital, Memory and Mixed-Signal VLSI Circuits, by M.L. Bushnell and V.D. Agrawal

"Core problem: Find a test vector for a given fault.

Combine the “core solution” with a fault simulator into an ATPG system."

ATPG is a Search Problem

Need to deal with good vs faulty circuit -- Alternatively use multi valued algebra of signal values for both good and faulty circuit.

Binary Decision Diagram

Combinational Circuit Testing -- VLSI Test Technology and Reliability (ET4076)

Scan design makes sequential test combinational

"Designer gives small set of functional tests (~ 70% FC) Augment with structural tests to boost coverage to 98 + %"

Roth’s 5-Valued and Muth’s 9-Valued  ATPG algebra: higher order Boolean set of notation to presents both good and failing circuit simultaneously -- slide 10

Untestable faults in combinational circuits indicates redundant hardware

Boolean Difference Symbolic Method (Sellers et al.) - slide 14, Lecture 3, Chapter 7ATPG basics

Fault Sensitization

Fault propogation

Line Justification

D-frontier --- chain of D or Dbar

Forward implication

Backward implication

Implication Stack

Branch and Bound Search

Good project for students to implement the above in code.

Memory Testing





Thursday, September 21, 2023

The Leader in My Life By:AG 2023

         Have you ever thought about having a leader? In my opinion, I think the leader in my life is a police officer. I think that because they keep people from breaking laws and more. Did you know catching criminals is not the only job they have? They also regulate traffic and solve cases. Police officers go through many challenges and some don't live long. It's so kind how they sacrifice their lives for us citizens. They have to do many exercises to make sure they are fit so they can fight smoothly. They also have to cooperate with descisions they might like or not like. Some police have different jobs such as a military police officer and lots more. He or she might have gone through many injuries. For example, some have helped in the army. Imagine if there was no police and you have been robbed who will help you? A police dog is also helpful. Some trained dogs can sniff out bombs and find out if someone has cancer just by sniffing them. In conclusion, police have done many things like catching criminals and tons more. So if you ever see them be sure to thank them for making the world a better place.

Saturday, September 02, 2023

A green pinecone



 Have you seen a green pine cone?

Stranded on the side walk, I couldnt help but stop and pick it up. I have never seen a green one before. 

A friend remarked its because of the storm yesterday. The road is strewn with the green pine needles.

The scales are still closed. Who else likes upcoming pinecones? The squirrel ofcourse.


Tonogayato gardens show the 3 year process from flower to brown cone
Penguin and Pinecone

Have you ever held a palm frond in your hand?