Computer Science 150 Homework Assignment 8
Spring 1997
Due: Thursday, April 17, 5:00 pm
The numbers in brackets [ ] denote the relative marks assigned for
each question.
(1) Consider the following combinational
circuit:
(a) [10] Using the definitions presented in class,
what is the total number of possible (physical) stuck-at-0 (SA0)
faults in this network? How many stuck-at-1 faults?
(b) [20] Use fault-folding techniques to eliminate
equivalent or implied faults and list all essential faults in the
network (use "gateName:inputName" or "gateName:outputName"
to refer to specific gate inputs or outputs, and name the input and output
pins directly e.g. A2:b, O2:z, I2, X2).
(c) [20] Identify a list of input "cubes"
that could be used to test the network for all essential stuck-at faults.
(d) [20] List the minimum set of test
vectors (i.e. reduce cubes to specific 1/0 vectors) needed to test
the circuit (i.e. manufacturing test, not diagnostic test) for all possible
stuck-at faults.
(e) [10] Can you find a set of vectors that would
be able to identify the specific fault causing a problem (i.e. fault
diagnosis) for all stuck-at faults? Explain how you go about it. Which
faults can you not identify uniquely?
(2) [20] An asynchronous circuit
has two inputs and two outputs. All possible input sequences
and the required output sequence are tabulated below:
Input sequence: 00, 10, 11, 01, 00
Output sequence: 00, 00, 10, 00, 00
Input sequence: 00, 01, 11, 10, 00
Output sequence: 00, 00, 01, 00, 00
Input sequence: 00, 10, 00, 01, 00
Output sequence: 00, 00, 00, 00, 00
Input sequence: 00, 01, 00, 10, 00
Output sequence: 00, 00, 00, 00, 00
Derive a minimum-row flow table for
the network
pchong@cory.eecs.berkeley.edu