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