Computer Systems Organization I - Prof. Grishman

Assignment #7  (Logic design)

1. (P&P exercise 3.9) Fill in the truth table for the logical expression NOT(NOT(A) OR NOT(B)).  What single logic gate has the same truth table?

2. (P&P exercise 3.16, slightly modified)  Given the following truth table for a 3-input even-parity circuit, write the sum-of-products Boolean formula for Z, and draw the gate-level logic circuit.
A
B
C
Z
0
0
0
1
0
0
1
0
0
1
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
0

3. (P&P execise 3.22, slightly modified)  Implement a 4-to-1 multiplexer (figure 3.13) using (only) three 2-to-1 multiplexers (figure 3.12).  Draw the resulting circuit, using the symbol for a 2-to-1 multiplexer, figure 3.12 (c). The circuit will have four data inputs, A, B, C, and D, two select inputs, S0 and S1, and one output.

4. Write the truth table for the following circuit.

(assignment 7 circuit)

Write your answers on one or more sheets of paper, staple the sheets together, and hand the sheet(s) in at the last class, December 13th.  The assignment is worth 5 points, with 1/2 point penalty for each weekday late.  If you are unable to submit the assignment in class on Dec. 13th, place it in Prof. Grishman's mailbox in Warren Weaver and send an email confirming submission to grishman@cs.nyu.edu .  If you submit it in the mailbox, there is a small risk of loss, so it is a good idea to make a copy of your assignment.