Download presentation

Presentation is loading. Please wait.

Published byGerard Hallmark Modified about 1 year ago

1
ECE 3110: Introduction to Digital Systems Chapter 6 Combinational Logic Design Practices XOR, Parity Circuits, Comparators

2
2 Exclusive OR and Exclusive NOR Gates XOR : XNOR : Truth Table : XOR X Y XOR XNOR XOR X Y F X Y F

3
3 XOR and XNOR Symbols Equivalent Symbols of XOR gate Equivalent Symbols of XNOR gate Any 2 signals (inputs or outputs) may be complemented without changing the resulting logic function

4
4 SSI XOR and XNOR 74x86 : 4 XOR gates 74x266: 4 XNOR gates with “open collector” or “open drain” output

5
5 XOR Application: Parity Circuit Odd Parity Circuit : The output is 1 if odd number of inputs are 1 Even Parity Circuit : The output is 1 if even number of inputs are 1 Example : 4-bit Parity Circuit Daisy-Chain Structure Tree structure Input : 1101 Odd Parity output : 1 Even Parity output : 0 I0 I1 I2 I3 ODD EVEN I0 I1 I2 I3 ODD EVEN

6
6 MSI Parity Circuit : 74x280

7
7 Parity-Checking Application: memory

8
8 Comparators Compares Two binary words and indicate if they are equal Magnitude Comparators : A Comparator A=B? B A Comparator A=B B A>B A**
{
"@context": "http://schema.org",
"@type": "ImageObject",
"contentUrl": "http://images.slideplayer.com/3378286/12/slides/slide_7.jpg",
"name": "8 Comparators Compares Two binary words and indicate if they are equal Magnitude Comparators : A Comparator A=B.",
"description": "B A Comparator A=B B A>B A
**

9
9 Equality Comparators 1-bit comparator 4-bit comparator EQ_L

10
10 Iterative Comparator

11
11 Multi-bit Iterative Comparator

12
12 MSI Comparator : 74x85 4 bit comparator 3 outputs : A=B, A B 3 Cascading inputs Functional Output equations : (A>B OUT)= (A>B)+(A=B).(A>B IN) (A**B IN) =0 (A BIN A**

13
13 8 bit Comparator B0 A1 B1 A2 B2 A3 A0 B3 74x85 A**B Most Significant bitsLeast Significant bits
**

14
14 8-bit Magnitude Comparator

15
15 Other conditions

16
16 Next… Adders, subtractors, ALUs Reading Wakerly CH

Similar presentations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google