1. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 1 The Digital Logic Level (3) Ass. Prof. Dr. Masri Ayob TK2123 : Lecture 16

2. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 2 Comparators 1-Bit Comparator1-Bit Comparator 2-Bit Comparator2-Bit Comparator 4-Bit Comparator4-Bit Comparator

3. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 3 Comparators 1-Bit Comparator1-Bit Comparator The output is 1 when the inputs are equal

4. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 4 Comparators 2-Bit Comparator2-Bit Comparator The output is 1 when A 0 = B 0 AND A 1 = B 1

5. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 5 Comparators 4-Bit Comparator4-Bit Comparator One of three outputs will be HIGH: A greater than B (A > B)A greater than B (A > B) A equal to B (A = B)A equal to B (A = B) A less than B (A < B)A less than B (A < B)

6. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 6 Decoders Binary decoderBinary decoder 4-bit decoder4-bit decoder BCD-to-decimal decoderBCD-to-decimal decoder

7. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 7 Decoders Binary decoderBinary decoder The output is 1 only when: A 0 = 1 A 2 = 0 A 3 = 0 A 4 = 1 This is only one of an infinite number of examples

8. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 8 Decoders 4-bit decoder4-bit decoder Logic Diagram

9. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 9 Decoders 4-bit decoder4-bit decoder –Binary inputs –Active-low outputs Truth Table

10. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 10 Decoders: BCD-to-decimal decoder

11. Floyd Digital Fundamentals, 9/e Copyright ©2006 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Slide 11 Thank you Q&A