Lecture 13 Introduction to Embedded Systems

1
Lecture 13Introduction to Embedded Systems

• Graduate Computer Architecture
• Fall 2005
• Shih-Hao Hung
• Dept. of Computer Science and Information
  Engineering
• National Taiwan University

2
Computing Systems

• Desktop
• PC, Workstations, Laptops
• Servers
• Tier-0 network appliance
• Tier-1 webserver
• Tier-2 application/database server
• File servers, Storage-area-network
• Embedded Systems
• PDA
• Cellphone
• Routers
• Microcontrollers

3
Embedded?

• Computing system embedded within electronic
  devices.
• Combination of computer hardware and software
  designed to performance a specific function.
• Any computing system that is not a desktop
  computer nor a server.

4
Area of Applications

• General purpose
• PDA
• Control systems
• Electronics, Automotive
• Signal processing
• Media player, Camera
• Communication
• Cellphone, switch

5
Market

• Average household uses 225 embedded processors
  about 35 for automobile
• Estimated 5 billion embedded processors in use
• 94 share of world market
• 6 Pentium, PowerPC, etc.
• Source World Semiconductor Trade Statistics
  Bluebook

6
Key IssuesUsers Point of View

• Single function/application
• Dedicated to specific type of tasks
• Tight constraints
• Size
• Power
• Cost
• Time-to-market
• Real-time
• Respond to environment in real time
• Safety/Reliability
• Failure can result in critical damages

7
Key IssuesDevelopers Point of View

• Concurrent development of HW and SW, i.e. HW/SW
  codesign
• Wide selection of uPs.
• Wide selection of OS, mostly real time (RTOS)
• Few system resources
• Specialized development tools
• Debugging skills important
• Robust HW/SW

8
Example
9
Elements
10
Trends

• High level of integration
• System-on-chip (SoC)
• Multiprocessor System-on-Chip (MPSoC)
• HW/SW co-design
• Concurrent development
• Optimization
• Design flow
• Design tools
• Experiences

11
Microcontroller

• Usually a simple uP plus peripheral support
  devices integrated in a single package

12
SoC

• A uP plus peripheral support devices integrated
  in a single chip
• E.g. Intel StrongARM
• SoC vs uController?

13
SoC Design

• Intellectual Property (IP)
• Circuits or cores pre-deisgned/pre-verified for
  certain functions
• Implications
• Lower design cost
• Fast time-to-market

14
Requirements

• Functional
• Functions
• I/O
• Non-functional
• Performance
• Cost
• Power consumption
• Size/weight

15
Architecture

• How to implement the specifications
• Components
• System structure
• Hardware/software partitioning
• HW/SW work together to solve a problem
• Partitioning decided by
• Performance
• Flexibility
• Cost

16
Architecture Design
17
Designing An Embedded System

• Understand the big picture
• Understand the details
• Design SW with
• Real time constraints
• Low power
• Small code size
• Domain-specific knowledge