Digital Electronics and Computer Interfacing Tim Mewes 3. Digital Electronics.

Slides:



Advertisements
Similar presentations
Sequential Logic Circuits. Set-Reset Latch The Set-Reset latch or bistable is a simple sequential logic circuit that remembers what has happened to the.
Advertisements

Changes in input values are reflected immediately (subject to the speed of light and electrical delays) on the outputs Each gate has an associated “electrical.
Introduction to Sequential Logic Design Latches. 2 Terminology A bistable memory device is the generic term for the elements we are studying. Latches.
Sequential Digital Circuits Dr. Costas Kyriacou and Dr. Konstantinos Tatas.
Give qualifications of instructors: DAP
Computer Science 210 Computer Organization Clocks and Memory Elements.
Latches CS370 –Spring 2003 Section 4-2 Mano & Kime.
Latches. Outline  Pulse-Triggered Latch  S-R Latch  Gated S-R Latch  Gated D Latch.
Digital Logic Design ESGD2201
CS 151 Digital Systems Design Lecture 19 Sequential Circuits: Latches.
ECE 331 – Digital System Design Latches and Flip-Flops (Lecture #17) The slides included herein were taken from the materials accompanying Fundamentals.
Flip-Flops, Registers, Counters, and a Simple Processor
Sequential Logic Latches and Flip-Flops. Sequential Logic Circuits The output of sequential logic circuits depends on the past history of the state of.
Sequential Circuits1 DIGITAL LOGIC DESIGN by Dr. Fenghui Yao Tennessee State University Department of Computer Science Nashville, TN.
Introduction to Sequential Logic Design Bistable elements Latches.
Module 12.  In Module 9, 10, 11, you have been introduced to examples of combinational logic circuits whereby the outputs are entirely dependent on the.
Nonlinear & Neural Networks LAB. CHAPTER 11 LATCHES AND FLIP-FLOPS 11.1Introduction 11.2Set-Reset Latch 11.3Gated D Latch 11.4Edge-Triggered D Flip-Flop.
CP208 Digital Electronics Class Lecture 11 May 13, 2009.
Logical Circuit Design Week 11: Sequential Logic Circuits Mentor Hamiti, MSc Office ,
Latches Chapter 14 Subject: Digital System Year: 2009.
Digital Logic Design Lecture 22. Announcements Homework 7 due today Homework 8 on course webpage, due 11/20. Recitation quiz on Monday on material from.
1 © 2014 B. Wilkinson Modification date: Dec Sequential Logic Circuits – I Flip-Flops A sequential circuit is a logic components whose outputs.
Digital Logic Design Brief introduction to Sequential Circuits and Latches.
+ CS 325: CS Hardware and Software Organization and Architecture Sequential Circuits 1.
Unit 11 Latches and Flip-Flops Ku-Yaw Chang Assistant Professor, Department of Computer Science and Information Engineering Da-Yeh.
Latches Module M10.1 Section 7.1. Sequential Logic Combinational Logic –Output depends only on current input Sequential Logic –Output depends not only.
EECC341 - Shaaban #1 Lec # 13 Winter Sequential Logic Circuits Unlike combinational logic circuits, the output of sequential logic circuits.
Latches Section 4-2 Mano & Kime. Sequential Logic Combinational Logic –Output depends only on current input Sequential Logic –Output depends not only.
Fall 2007 L16: Memory Elements LECTURE 16: Clocks Sequential circuit design The basic memory element: a latch Flip Flops.
Unit 11 Latches and Flip-Flops Ku-Yaw Chang Assistant Professor, Department of Computer Science and Information Engineering Da-Yeh.
ECE 301 – Digital Electronics Flip-Flops and Registers (Lecture #15)
ETE Digital Electronics Latches and Flip-Flops [Lecture:12] Instructor: Sajib Roy Lecturer, ETE, ULAB.
Astable: Having no stable state. An astable multivibrator oscillates between two quasistable states. Asynchronous Having no fixed time relationship Bistable.
Latches and Flip-Flops ELEC 311 Digital Logic and Circuits Dr. Ron Hayne Images Courtesy of Cengage Learning.
COE 202: Digital Logic Design Sequential Circuits Part 1
Flip Flop
ECE 101 An Introduction to Information Technology Digital Logic.
1 Boolean Algebra & Logic Gates. 2 Objectives Understand the relationship between Boolean logic and digital computer circuits. Learn how to design simple.
Multiplexers 1 The output is equal to one of several input signals to the circuit The multiplexer selects which input signal to use as an output signal.
Unit 11 Latches and Flip-Flops Fundamentals of Logic Design By Roth and Kinney.
Instructor: Alexander Stoytchev CprE 281: Digital Logic.
ECA1212 Introduction to Electrical & Electronics Engineering Chapter 9: Digital Electronics – Sequential Logic by Muhazam Mustapha, November 2011.
ITEC 352 Lecture 9 Flip Flops. Flip flops Review Questions? HW #2 posted, due next Friday at 10PM Floating point numbers.
Instructor: Alexander Stoytchev CprE 281: Digital Logic.
© 2009 Pearson Education, Upper Saddle River, NJ All Rights ReservedFloyd, Digital Fundamentals, 10 th ed Digital Logic Design Dr. Oliver Faust.
1 Synchronous Sequential Logic Sequential Circuits Every digital system is likely to have combinational circuits, most systems encountered in practice.
Digital Electronics and Computer Interfacing Tim Mewes 3. Digital Electronics.
LECTURE IX CH 5 LATCHES AND FLIP-FLOPS. Sequential logic circuits by definition progressive from one logic state to the next. In order for this to occur,
Synchronous Sequential Logic A digital system has combinational logic as well as sequential logic. The latter includes storage elements. feedback path.
Chapter 6 – Digital Electronics – Part 1 1.D (Data) Flip Flops 2.RS (Set-Reset) Flip Flops 3.T Flip Flops 4.JK Flip Flops 5.JKMS Flip Flops Information.
CO5023 Latches, Flip-Flops and Decoders. Sequential Circuit What does this do? The OUTPUT of a sequential circuit is determined by the current output.
 Flip-flops are digital logic circuits that can be in one of two states.  Flip-flops maintain their state indefinitely until an input pulse called a.
CS151 Introduction to Digital Design Chapter 5: Sequential Circuits 5-1 : Sequential Circuit Definition 5-2: Latches 1Created by: Ms.Amany AlSaleh.
A latch is a temporary storage device that has two stable states (bistable). It is a basic form of memory. The S-R (Set-Reset) latch is the most basic.
Sequential Devices Sequential concept: output depends on present as well as past inputs Past inputs influence operations via memory elements.
CENG 241 Digital Design 1 Lecture 7 Amirali Baniasadi
ECE 301 – Digital Electronics Brief introduction to Sequential Circuits and Latches (Lecture #14)
ECE 331 – Digital System Design Introduction to Sequential Circuits and Latches (Lecture #16)
4–1. BSCS 5 th Semester Introduction Logic diagram: a graphical representation of a circuit –Each type of gate is represented by a specific graphical.
7. Latches and Flip-Flops Digital Computer Logic.
CHAPTER 11 LATCHES AND FLIP-FLOPS This chapter in the book includes: Objectives Study Guide 11.1Introduction 11.2Set-Reset Latch 11.3Gated D Latch 11.4Edge-Triggered.
©2010 Cengage Learning SLIDES FOR CHAPTER 11 LATCHES AND FLIP-FLOPS Click the mouse to move to the next page. Use the ESC key to exit this chapter. This.
UNIT 11 LATCHES AND FLIP-FLOPS Click the mouse to move to the next page. Use the ESC key to exit this chapter. This chapter in the book includes: Objectives.
The George Washington University School of Engineering and Applied Science Department of Electrical and Computer Engineering ECE122 – Lab 7 Latches & Flip-flops.
LATCHES AND FLIP-FLOPS
Digital Design Lecture 9
Latches and Flip-Flops 2
Sequential Circuits: Latches
Latches and Flip-Flops 2
Week 11 Flip flop & Latches.
Presentation transcript:

Digital Electronics and Computer Interfacing Tim Mewes 3. Digital Electronics

Digital Electronics and Computer Interfacing2 3.7 Flip-flops A flip-flop is a digital circuit that is capable of serving as a one bit memory A flip-flop is constructed using gates So how could it possibly work? But we said that the output of a gate only depends on its inputs and not on its history?! No memory – output remains only as long as the inputs are set Somehow create a “loop” – called Feedback

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) One possible implementation: NAND gate latch S R Q Q

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) Reset of the flip-flop: S=1, R=0 S R Q Q ? 00 1

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) Set of the flip-flop: S=0, R=1 S R Q Q ? 11 0

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) What happens when we now change to: S=1, R=1 ? S R Q Q  Flip-flop does not change its output ! (latch)

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) What happens for: S=0, R=0 ? S R Q Q 0 ? ?  Both outputs are 1! Q  NOT(Q) !!!

Digital Electronics and Computer Interfacing Set/reset flip-flop (SR flip-flop) Summary S R Q Q Q R S invalid Timing diagram

Digital Electronics and Computer Interfacing Gated SR flip-flop Sometimes also called: Clocked SR flip-flop S’ R’ Q Q E The input E is called enable input or clock input

Digital Electronics and Computer Interfacing Gated SR flip-flop Reset of the gated SR flip-flop: S’=0, R’=1 and E=1 S’ R’ Q Q E S R This corresponds to the Reset case (S=1, R=0) of the SR flip-flop (page 4) Thus: Q=0 and Q=1 0 1

Digital Electronics and Computer Interfacing Gated SR flip-flop Set of the gated SR flip-flop: S’=1, R’=0 and E=1 S’ R’ Q Q E This corresponds to the Set case (S=0, R=1) of the SR flip-flop (page 5) Thus: Q=1 and Q=0 1 0 S R

Digital Electronics and Computer Interfacing Gated SR flip-flop What happens if we now set E=0? S’ R’ Q Q E With E=0 the flip-flop does not change its outputs! S R

Digital Electronics and Computer Interfacing Gated SR flip-flop Summary Q R’ S’ Timing diagram S’ R’R’ Q Q E E 0 1 invalid