Unformatted text preview: ELEC 2200 Homework #15 – Due Friday, July 8 1. A digital system is to have three 8‐bit binary number inputs: A (a7‐a0), B (b7‐b0), and C (c7‐c0), and 8‐bit “result” output R (r7‐r0), and a 2‐bit function code, f1f0, to select one of the four arithmetic operations in the following table. f1 f0 Function 00 R = A + B 01 R = A + C 10 R = A – B 11 R = B ‐ C Design a digital circuit that will implement the functions listed in the above table. Your circuit should contain as few individual logic gates as possible. Instead, you are to use a minimal number of “modules” from Chapter 4 of the text, such as 7483 4‐bit adders, 74157 multiplexers, etc. (do not draw the gate‐level circuits of these modules – see Figure 4.41 for an example.) Show all work in the derivation of this circuit, and provide a brief explanation of how each of the four functions in the above table is implemented. 2. Using only 9 AND gates plus a number of 1‐bit full adders and/or half adders, design a circuit that will produce the 6‐bit product of two 3‐bit unsigned binary numbers: P = A x B, where P = (p5p4p3p2p1p0), A = (a2a1a0), B =(b2b1b0) Hint: Examine how you would do the multiplication with “pencil and paper”, producing partial products and then adding them. The AND gates can be used to create the partial products, and the adder modules can produce the sum. ...
View Full Document
- Summer '08
- binary number inputs, individual logic gates