ECE 3110: Introduction to Digital Systems

Introduction (Contd.)

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Previous class Summary Digital devices Digial vs analog Why digial

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Digital Devices Gates: has one or more inputs and

produces an output that is a function of the current input values. AND, OR, NOT…

Flip-flop: a device that stores 0 or 1. A FF can be built from a collection of gates.

Combination circuit: gates Sequential circuit:FFs+gates, has a

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

SpecificationsElectronic Circuit Designer, Digital Designer

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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) A collection of one or more gates

fabricated on a single silicon chip. Wafer, die

Copyright © 2001 Fine Arts Photographics

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Integrated Circuits (IC) Small-scale integration (SSI): 1-20

DIP: dual in-line-pin package Pin diagram, pinout

MSI: 2-200 gates LSI: 200-200,000

VLSI: >100,000, 50million (1999)

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DIP

pinout

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Programmable Logic Device (PLD) ICs which Logic function can be

programmed after manufacture. 2-level AND-OR gates using user-

programmable connections PLAs: programmable Logic Arrarys. PALs: programmable array logic devices Programmable logic devices (PLDs)

CPLD: complex PLD FPGA: Field-Programmable Gate Array

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CPLD vs FPGA

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Application-Specific ICs (ASIC) Semicustom IC: chips designed for a

particular, limited product/application Reducing chip count, size, power

consumption Higher performance. NRE: nonrecurring engineering cost

Standard cells: library Gate arrary: an IC with internal structure as

an array of gates, unspecified interconnection

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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 technology MCM: multichip modules: high

speed and density.

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Digital Design Levels Many representations of digital logic Device Physics and IC manufacturing

Moore’s Law [1965, Gordon Moore]:

Transistor level --->Logic design, functional building blocks

The number of transistors per square inch in an IC doubles every year [18months].

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Digital Design Levels Transistor-level circuit diagrams Example: Multiplexor

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Truth tables

Gate-level Logic diagrams

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Prepackaged building blocks, e.g. multiplexer

Equations: Z = S A+ S B

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Various hardware description languages ABEL

VHDL

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Summary Electronics/sw aspects of digital

design Integrated Circuits

(wafer,die,SSI,MSI,LSI,VLSI) PLDs: PLAs,PALs,CPLD,FPGA ASIC Digital Design Levels

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Next… Number systems

Reading: Wakerly chapter 2

HW #1 Assign Thursday 01/22/2004:

Work Wakerly problems 1.3, 1.5, 1.6                  

Due:    Tuesday 01/27/2004