Test of VLSI 4 UPDATED ACTUAL Exam Questions and CORRECT Answers

Test of VLSI 4 UPDATED ACTUAL Exam
Questions and CORRECT Answers
Purpose of testability measure - CORRECT ANSWER - Need to have a computationally
inexpensive method to quantify
how hard it is to set or observe internal signals of a circuit


Controllability - CORRECT ANSWER - difficulty of setting a particular signal to logic 0
or 1


Observability - CORRECT ANSWER - difficulty of observing the state of a particular
signal


Testability analysis - CORRECT ANSWER - Most popular algorithm: SCOAP (Sandia
Controllability/Observability
Analysis Program)


What does SCOAP measure ? - CORRECT ANSWER - • Controllability
is presented as a number ranging from 1 (easiest) to infinity (hardest)
• Observability
is presented as a number ranging from 0 (easiest) to infinity (hardest)
• Combinational measures
- controllability/observability applied to a strictly combinational circuit
- roughly proportional to the number of circuit lines that must be set to
control or observe given line
• Sequential measures
- controllability/observability applied to a sequential circuit
- roughly proportional to the number of times a flip-flop must be clocked to
control or observe given line