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Anteprima

ESTRATTO DOCUMENTO

PLD (Programmable Logic Device)

• All layers already exist

– Designers can purchase an IC

– Connections on the IC are either created or destroyed to

implement desired functionality

– Field-Programmable Gate Array (FPGA) very popular

• Benefits

– Low NRE costs, almost instant IC availability

• Drawbacks

– Bigger, expensive (perhaps $30 per unit), power hungry,

slower

Embedded Systems Design: A Unified 11

Hardware/Software Introduction, (c) 2000 Vahid/Givargis

Moore’s law

• The most important trend in embedded systems

– Predicted in 1965 by Intel co-founder Gordon Moore

IC transistor capacity has doubled roughly every 18 months

for the past several decades

10,000

1,000

100

Logic transistors

per chip 10

(in millions) 1

0.1

Note: 0.01

logarithmic scale 0.001 2005

1999 2001

1993

1991

1987 2009

2007

2003

1995 1997

1989

1985

1981 1983

Embedded Systems Design: A Unified 12

Hardware/Software Introduction, (c) 2000 Vahid/Givargis 6

Moore’s law

• Wow

– This growth rate is hard to imagine, most people

underestimate

– How many ancestors do you have from 20 generations ago

• i.e., roughly how many people alive in the 1500’s did it take to make

you?

20 =

• 2 more than 1 million people

– (This underestimation is the key to pyramid schemes!)

Embedded Systems Design: A Unified 13

Hardware/Software Introduction, (c) 2000 Vahid/Givargis

Graphical illustration of Moore’s law

1981 1984 1987 1990 1993 1996 1999 2002

10,000 150,000,000

transistors transistors

Leading edge Leading edge

chip in 1981 chip in 2002

• Something that doubles frequently grows more quickly

than most people realize!

– A 2002 chip can hold about 15,000 1981 chips inside itself

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Hardware/Software Introduction, (c) 2000 Vahid/Givargis 7

Design Technology

• The manner in which we convert our concept of

desired system functionality into an implementation

Compilation/ Libraries/ Test/

Synthesis IP Verification

System Model simulat./

System Hw/Sw/

Compilation/Synthesis: specification checkers

synthesis OS

Automates exploration and

insertion of implementation

details for lower level. Behavior Cores Hw-Sw

Behavioral synthesis cosimulators

specification

Libraries/IP: Incorporates pre-

designed implementation from

lower abstraction level into

higher level. RT RT HDL simulators

RT synthesis components

specification

Test/Verification: Ensures correct

functionality at each level, thus Logic Gates/ Gate

reducing costly iterations Logic synthesis Cells simulators

between levels. specification

To final implementation

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Hardware/Software Introduction, (c) 2000 Vahid/Givargis

Design productivity exponential increase

100,000

10,000 Mo.

1,000 –

Productivity Trans./Staff

100

10

1 (K)

0.1

0.01

2005

1993 2001 2003

1983 1985 1987 1991

1981 1989 1999

1997 2007

1995 2009

• Exponential increase over the past few decades

Embedded Systems Design: A Unified 16

Hardware/Software Introduction, (c) 2000 Vahid/Givargis 8

The co-design ladder

• In the past: Sequential program code (e.g., C, VHDL)

Behavioral synthesis

– Hardware and software Compilers (1990's)

(1960's,1970's)

design technologies were Register transfers

very different Assembly instructions RT synthesis

– Recent maturation of (1980's, 1990's)

Assemblers, linkers

synthesis enables a unified Logic equations / FSM's

(1950's, 1960's) Logic synthesis

view of hardware and (1970's, 1980's)

Machine instructions

software Logic gates

• Hardware/software Implementation

“codesign” Microprocessor plus VLSI, ASIC, or PLD

program bits: “software” implementation: “hardware”

The choice of hardware versus software for a particular function is simply a tradeoff among various

design metrics, like performance, power, size, NRE cost, and especially flexibility; there is no

fundamental difference between what hardware or software can implement.

Embedded Systems Design: A Unified 17

Hardware/Software Introduction, (c) 2000 Vahid/Givargis

Independence of processor and IC

technologies

• Basic tradeoff

– General vs. custom

– With respect to processor technology or IC technology

– The two technologies are independent

General- Single-

ASIP

purpose purpose

General, Customized,

processor processor

providing improved: providing improved:

Flexibility Power efficiency

Maintainability Performance

NRE cost Size

Time- to-prototype Cost (high volume)

Time-to-market

Cost (low volume) PLD Semi-custom Full-custom

Embedded Systems Design: A Unified 18

Hardware/Software Introduction, (c) 2000 Vahid/Givargis 9


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DESCRIZIONE DISPENSA

Technology is a manner of accomplishing a task, especially using technical processes, methods, or knowledge.
There are three key technologies for embedded systems:
Processor technology;
IC technology;
Design technology.


DETTAGLI
Corso di laurea: Corso di laurea magistrale in ingegneria delle telecomunicazioni
SSD:
Università: L'Aquila - Univaq
A.A.: 2011-2012

I contenuti di questa pagina costituiscono rielaborazioni personali del Publisher Atreyu di informazioni apprese con la frequenza delle lezioni di Sistemi embedded e studio autonomo di eventuali libri di riferimento in preparazione dell'esame finale o della tesi. Non devono intendersi come materiale ufficiale dell'università L'Aquila - Univaq o del prof Pomante Luigi.

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