Implement a Transparent - Computer Engineering - Exam, Exams of Computer Science

Download Implement a Transparent - Computer Engineering - Exam and more Exams Computer Science in PDF only on Docsity!

4 problems, 5 pages Exam Two 15 October 1999

Name (print) _____________________________________________________

1 2 3 4 total

Escher Memory Cell

4 problems, 5 pages Exam Two 15 October 1999

Problem 1 (3 parts, 28 points) Art of the State

Part A (10 points) Implement a transparent latch using only six two-input NOR gates. Label the inputs In and En , and the output Out. No other gates should be used.

Part B (8 points) Implement register with write enable using transparent latches, NAND gates, and inverters. Use an icon for the transparent latches. Label the inputs In , WE, ΦΦΦΦ 1 , ΦΦΦΦ 2 and the output Out.

Part C (10 points) Assume the following signals are applied to your register. Draw the output signal Out. Draw a vertical line where In is sampled. Assume Out starts at zero.

Φ 1

Φ 2

WE

In

Out

4 problems, 5 pages Exam Two 15 October 1999

Problem 3 (2 parts, 24 points) Simplification with Don’t Cares

Part A (12 points)For the following behavior (in map format), derive a simplified sum of products expression using a Karnaugh Map. Circle and list the prime implicants, indicating which are essential. Then write the simplified SOP expression.

simplified SOP expression

Part B (12 points) For the following behavior (in map format), derive a simplified product of sums expression using a Karnaugh Map. Enter the behavior in the map. Circle and list the prime implicants, indicating which are essential. Then write the simplified POS expression.

simplified POS expression

4 problems, 5 pages Exam Two 15 October 1999

Problem 4 (2 parts, 20 points) Priority Fun

Consider a 8 to 3 priority encoder with the following priority:

(lowest priority) I 4 < I 6 < I 0 < I 1 < I 3 < I 2 < I 7 < I 5 (highest priority)

Part A (10 points) Complete the following truth table with appropriate inputs and outputs for this priority scheme:

I 7 I 6 I 5 I 4 I 3 I 2 I 1 I 0 O 2 O 1 O 0 Valid

0 0 0 0 0 0 0 0

1 1 1 1 1 1 1 1

Part B (10 points) Complete the truth table for the following unusual logic block

A B

Out

A B Out

0 0

1 0

0 1

1 1