1 Introduction to ES Architectures Components and Systems Embedded - - PDF document

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General Purpose vs. Application Specific Processors Slide 1 Eduard Turcan October 24, 2001

Processors and Architectures for Embedded Systems

General Purpose vs. Application Specific Processors

General Purpose vs. Application Specific Processors Slide 2 Eduard Turcan October 24, 2001

Lectures 5 & 6 Overview

• General Purpose vs. Application Specific

Processors

• Core (IP)-based design
• Reconfigurable Systems

General Purpose vs. Application Specific Processors Slide 3 Eduard Turcan October 24, 2001

Agenda

• Trends in Embedded-Microprocessor design
• Embedded System Architectures
• Customized Instruction Sets for Embedded

Processors

• Selected Co-design problems
• Conclusions

General Purpose vs. Application Specific Processors Slide 4 Eduard Turcan October 24, 2001

Embedded Microprocessors Overview

• Desktop vs. Embedded processors
• Microcontrollers and Microprocessors
• New applications drive requirements

– game consoles – handheld, palmtop, automobile and network PCs – cellular phones and other mobile communicators – modems, fax machines, printers, etc. – digital cameras

Trends in Embedded Microprocessor design General Purpose vs. Application Specific Processors Slide 5 Eduard Turcan October 24, 2001

Comparing Embedded Processors

• Power consumption
• Code density
• Peripheral integration and chipsets
• Multimedia acceleration
• Price/performance ratio

Trends in Embedded Microprocessor design General Purpose vs. Application Specific Processors Slide 6 Eduard Turcan October 24, 2001

Standardization

• The heterogenity of embedded architectures
• A need to unify the embedded processor market?
• Windows CE and JAVA as examples
• Will management influence standardization?

Trends in Embedded Microprocessor design

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General Purpose vs. Application Specific Processors Slide 7 Eduard Turcan October 24, 2001

Introduction to ES Architectures

• ES Architectures are determined by:

– circuit technology; – application requirements; – market constraints:

• strict cost margins
• time-to-market and predictable design time
• (hard) time constraints
• power dissipation
• safety
• physical constraints

Embedded System Architectures Introduction General Purpose vs. Application Specific Processors Slide 8 Eduard Turcan October 24, 2001

Components and Systems

• Components as function blocks
• Systems as large entities of integrated

components

• Single control thread vs. multiple control threads
• architecture specialization

– component specialization techniques – system specialization techniques

Embedded System Architectures Architecture Specialization Techniques General Purpose vs. Application Specific Processors Slide 9 Eduard Turcan October 24, 2001

Component Specialization Techniques

• Instruction set specialization
• Function unit and data path specialization
• Memory specialization
• Interconnect specialization
• Control specialization

Embedded System Architectures Architecture Specialization Techniques General Purpose vs. Application Specific Processors Slide 10 Eduard Turcan October 24, 2001

System Specialization Techniques

• Load distribution

– Control decomposition (control clustering) – Data decomposition (data clustering)

• Component interaction

Embedded System Architectures Architectures Specialization Techniques General Purpose vs. Application Specific Processors Slide 11 Eduard Turcan October 24, 2001

System Control Specialization

• Asymmetric control relationships require global

control flow

• The following global control mechanisms can be

distinguished:

– Independently controlled components – Dependent coprocessors – Incrementally controlled coprocessors – Partially dependent coprocessors

Embedded System Architectures Architecture Specialization Techniques General Purpose vs. Application Specific Processors Slide 12 Eduard Turcan October 24, 2001

Dependent Coprocessors

Embedded System Architectures Architecture Specialization Techniques

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General Purpose vs. Application Specific Processors Slide 13 Eduard Turcan October 24, 2001

Incrementally Controlled Coprocessors

Embedded System Architectures Architecture Specialization Techniques General Purpose vs. Application Specific Processors Slide 14 Eduard Turcan October 24, 2001

Partially Dependent Coprocessors

Embedded System Architectures Architecture Specialization Techniques General Purpose vs. Application Specific Processors Slide 15 Eduard Turcan October 24, 2001

Application System Classes

• Computation oriented systems
• Control dominated systems
• Data dominated systems
• Mixed systems

Embedded System Architectures Embedded System Architectures Target Architectures and Application System Classes General Purpose vs. Application Specific Processors Slide 16 Eduard Turcan October 24, 2001

Control Dominated Systems Architectures

• Input MOCs are coupled FSM or Petri-Nets
• Co-design problems:

– execution of concurent FSMs/Petri-Nets reacting to asynchronous input events – FSM transition synchronization – event scheduling – correctness

Embedded System Architectures Architectures for Control Dominated Systems General Purpose vs. Application Specific Processors Slide 17 Eduard Turcan October 24, 2001

8051 - an 8bit Microcontroller Architecture

Embedded System Architectures Architectures for Control Dominated Systems General Purpose vs. Application Specific Processors Slide 18 Eduard Turcan October 24, 2001

Examples - Philips 80C552

Embedded System Architectures Architectures for Control Dominated Systems

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General Purpose vs. Application Specific Processors Slide 19 Eduard Turcan October 24, 2001

Data Dominated Systems Architectures

• Data transport or processing is dominant
• Flow graph languages are used to describe such

systems

• Opportunities for specialization:

– periodic execution often corresponds to a input data independent system data flow – input data is mostly generated with a fixed period (the sample rate)

Embedded System Architectures Architectures for Data Dominated Systems General Purpose vs. Application Specific Processors Slide 20 Eduard Turcan October 24, 2001

Examples - MMX

Embedded System Architectures Architectures for Data Dominated Systems General Purpose vs. Application Specific Processors Slide 21 Eduard Turcan October 24, 2001

Examples - Hitachi SH-DSP

Embedded System Architectures Architectures for Data Dominated Systems General Purpose vs. Application Specific Processors Slide 22 Eduard Turcan October 24, 2001

Examples - Philips Trimedia TM1000

Embedded System Architectures Architectures for Data Dominated Systems General Purpose vs. Application Specific Processors Slide 23 Eduard Turcan October 24, 2001

Examples - TI TMS320C80

Embedded System Architectures Architectures for Data Dominated Systems General Purpose vs. Application Specific Processors Slide 24 Eduard Turcan October 24, 2001

Customized Instruction-Sets

• Instruction-Set Architectures (ISAs) are the

visible instructions of a processor

• Is there a strong motivation for customizing

processors’ instruction-sets?

Customized Instruction Sets Introduction

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General Purpose vs. Application Specific Processors Slide 25 Eduard Turcan October 24, 2001

Barriers

• Existing binaries
• Toolchain costs and user familiarity
• Lost savings/higher chip cost due to lower

volumes

• Hardware development costs
• The product development cycle for embedded

products

Customized Instruction Sets Barriers General Purpose vs. Application Specific Processors Slide 26 Eduard Turcan October 24, 2001

Co-design Problems

• Instruction-set definition
• Instruction encoding for code compression
• Instruction encoding for memory optimization
• Global control and data flow optimization
• Communication channel selection
• Component interface synthesis
• Component selection/reuse

General Purpose vs. Application Specific Processors Slide 27 Eduard Turcan October 24, 2001

Conclusions

?