Past Paper Qs.

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kota

Joined Apr 14, 2011
1
Question: Using Kmaps, design an arithmetic and logic unit that can perform functions of three 1-bit variables X, Y, Z as shown
M1 M2 FUNCTION RESULT COMMENT
0 0 ADD X+Y+Z + is arithmetic add
0 1 Subtract X-Y-Z - is aritmetic subtract
1 0 AND X.Y.Z . is boolean AND
1 1 OR X+Y+Z + is boolean OR

My guess at this question is as follows,
5 input, so a 5 variable Kmap.

What i dont get is, for the arithmetic part, do I need a separate LED to show carry/borrow occurred? And when I'm doing out the state table, is this how I should go about it

X Y Z | M1 M2| Present Output
0 0 0 | 0 0 | 0
| 0 1 | 0
| 1 0 | 0
| 1 1 | 0
0 0 1 | 0 0 | 1

.... and so on. It seems a bit long winded?
Thanks for any help and comments. I hope I've gotten at least one part right. Even if it is only the question taken down right.
 
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