ECE 2110: Introduction to Digital Systems

Introduction (Contd.)

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Previous class Summary

Digital devicesDigital vs. analogWhy digital

ECE 2110: Introduction to Digital systems

Digital Devices

Gates: AND, OR, NOT (inverter): most important gates. Can

realize any digital function.NAND, NORXOR, XNOR

Flip-flops (FF):Stores 0/1, built from gates

Gates: Combinational circuit: output depends ONLY on the current input combination.

Flip-flops: Sequential circuit: output depends on current input As Well As past sequence of inputs. Hence, it has memory of past events.

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Digital Logic

Binary system -- 0 & 1, LOW & HIGH, negated and asserted.

Basic building blocks -- AND, OR, NOT

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Electronic aspect of digital design

Digital abstraction

Range

Noise margin

Invalid range

Specifications

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Software aspect of digital design

Digital design need not involve any software tools.

But: modern design, software tools are essential.

Examples:Schematic entry, HDLs (platform compilers, simulators,

synthesis tools), simulators, test benches, timing analyzers and verifiers, word processors, high-level languages, CAD

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Integrated Circuits (IC) (Chapter 1.6--1.12)

A collection of one or more gates fabricated on a single silicon chip.Wafer, die

Small-scale integration (SSI): 1-20 gatesDIP: dual in-line-pin packagePin diagram, pinout

MSI: 20-200 gatesLSI: 200-1,000,000VLSI: Fuzzy! Transistor count reached 50million

in 1999 and 100 million in 2005.

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DIP

pinout

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Printed-Circuit Board

PCB or PWB (printed-wiring board)Mount ICs so that an IC can connect to

other ICs in a system.SMT: Surface-mount technologyMCM: multi-chip modules: high speed and

density.

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Summary

Electronics aspects of digital designIntegrated Circuits SSI, MSI, LSI, VLSIPrinted Circuit Boards

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Next…

HW#1: a) Work problems 1.[3,6]

        b) Discuss three advantages of digital systems over analog ones.

Finish reading Chapter 1,If you use web search such as:

www.acronymfinder.com for homework #1, make sure that definitions you chose are consistent with the text you read.

Start Reading: Wakerly chapter 2: Number systems