Embedded Systems James M. Conrad

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Embedded SystemsJames M. Conrad
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Outline of Talk

• Definition of embedded systems (are they
  imbedded?)
• Embedded processors (microcontrollers vs.
  microprocessors)
• Real-Time Operating Systems (RTOS)
• Examples of embedded systems
• Current courses in Embedded Systems
• Conclusions
• Contact info

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Computers are Everywhere

• Q Where are computers today?
• On your desktop (of course!)
• In your microwave oven
• Controlling automobiles
• In a Palm Pilot PDA
• In your pager
• In a cell phone
• In a Nintendo console
• In your Gameboy . . .
• Everywhere!

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What is Embedded?
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What is an Embedded System?

• A microprocessor based device which has
• Pre-defined, specific functions
• Constrained resources (memory, power)
• Application runs from ROM
• Computer purchased as part of some other piece of
  equipment
• Typically dedicated software (may be
  user-customizable)
• Often replaces previously electromechanical
  components
• Often no real keyboard
• Often limited display or no general-purpose
  display device

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A Customer View

• Reduced Cost
• Increased Functionality
• Improved Performance
• Increased Overall Dependability

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What is Driving Embedded System Growth?

• Microprocessor performance increasing
• Microprocessor cost decreasing
• Growing markets
• More applications
• Greater functionality and complexity
• Need to reduce time to market
• Leverage technology resources
• Outsourcing to off-the-shelf solutions

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How Big is it?

• Embedded is the largest and fastest-growing part
  of the worldwide microprocessor industry
• Embedded is approximately 100 of worldwide unit
  volume in microprocessors
• Average of 30-40 processors per home in US
• (only 5 are within the home PC)
• Turleys Law
• The amount of processing power on your person
  will double every 12 months
• Analysts say...
• Embedded systems in over 90 of worldwide
  electronic devices
• By 2010, there will be 10 times more embedded
  programmers than others

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Microcontroller vs. Microprocessor

• Microcontroller has peripherals for embedded
  interfacing andcontrol
• Analog
• Non-logic levelsignals
• Timing
• Communications
• point to point
• network
• Reliability and safety

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Designing a Microcontroller into a System
Digital interfacing Analog interfacing Communicati
ons

• Power supply
• Clock signal generator
• Reset controller
• Memory

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Anatomy of an Embedded Project
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Anatomy of an Embedded Project

• Choose development tools - (compiler suite,
  debugger, simulator)

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• Often not an independent decision from RTOS
• Embedded Systems Buyers Guide lists gt 50 compiler
  and gt 50 debugger suppliers
• VDC report Worldwide Market for Embedded
  Software analyzes market leaders

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Anatomy of an Embedded Project
Platform Developers
Application Developers
Board support package Device drivers Hardware
debug - JTAG, ICE
Native development OS simulation or Eval
platform Code Centric tools
Runtime analysis Advanced debug modes Code
optimization
Integrate and Test
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Architecture of a Real-Time OS

• pSOSystem is modular, containing pSOSKernel plus
  a collection of selectable components and
  libraries

User Application
NFS
FTP
DNS
Telnet
RCP
DHCP
POSIX
SharedLib Mgr
TCP/UDP/IP
C Run Timelibrary
Loader
File Systems
PPP
NAT
X.25
Real Time Multitasking kernel
Board Support Package (Boot code, Drivers,
Configuration files)
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Case Study T68 Printed Circuit Board

• From Electronic Engineering Times, May 13, 2002,
  p. 30

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Case Study T68 Block Diagram

• From Electronic Engineering Times, May 13, 2002,
  p. 30

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Topics Taught in Embedded Systems Course

• Introduction to Embedded Systems and
  Microcontroller-based Circuit Design
• Renesas (Mitsubishi) 16C Instruction Set
  Architecture
• C Programming Review and Dissection
• The MSV30262-SKP Starter Kit and Tutorial
• Interrupts, C Start-Up Module and Simple Digital
  I/O
• Debugging Software and Hardware
• Algorithms and Software Design
• Using and Programming Interrupts in C
• Sharing Data and Interrupt-Driven Serial
  Communications
• Round-Robin Non-Preemptive Scheduler
• Analog to Digital Conversion
• Software Testing
• Processes Coordination and Simple Scheduling
• Scheduling and Watchdog Timers
• Memory Expansion and DMA
• Performance Analysis
• Creating an Embedded System Architecture

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Microcontroller Board Used in Course

• M16C/26 family of microcontrollers
• M30262
• Excellent development environment and tools come
  with the board
• C compiler
• Monitor Board
• USB support
• Each student purchases, 50 a board

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Embedded Class Development Board
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Robotics - Stiquito
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Stiquito - What Is It?

• Invented by Jonathan Mills, CS Department,
  Indiana University, in 1992.
• Hexapod (six legs)
• Small - can sit on a credit card(75mm x 70mm x
  25mm, 10g)
• Inexpensive (5.00 in mass quantities),
  easy-to-build
• Can carry about 50g of weight
• Travels using a Nitinol muscle (also comprises
  1/2 of the cost of the kit)

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Stiquito Books

• Stiquitotm Advanced Experiments with a Simple
  and Inexpensive Robot, ISBN 0-8186-7408-3, IEEE
  Computer Society Press/Wiley, 1997.
• Stiquitotm for Beginners An Introduction to
  Robotics, ISBN 0-8186-7514-4, IEEE Computer
  Society Press/Wiley, 1999.
• Stiquitotm Controlled!, ISBN 0-4714-8882-8 ,
  IEEE Computer Society Press/Wiley, 2004. Book
  includes embedded board, shown at right.

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The Stiquito Robot

• Two books published by the IEEE CS Press show
  users how to build a low-cost robot
• Books include the materials to build the
  Stiquito robot body.
• The books describes how to build circuits to
  control the hexapod robot, but do not include the
  materials to build the control circuits.
• The ideal book would also include a circuit
  board INSIDE the book to make the robot walk.
• A third book, Stiquito Controlled!, will include
  instructions for making a life-like walking
  insect robot using the TI430 microcontroller.

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Embedded System - Robot

• Robotics relies on one or more microprocessors/
  microcontrollers for full closed-loop operation
• Sense the environment (i.e. bump, sonar, light)
• Make decisions based on input
• Control the robot and devices (i.e. drive system,
  radio)
• The Stiquito Controller Board is open-loop
  there is no sensing.
• Supports one and two degree-of-freedom operation
  (forward/back versus both forward/back and
  up/down)
• Expandable can add other components and
  programming interface

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Schematic of Stiquito Controller Board
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Design Decisions

• The MSP430F1122 (flash variant) selected based on
  functionality and cost.
• The board circuit also includes an ULN2803
  Darlington Transistor array to drive current
  through the robots muscles (nitinol).
• The board also contains some LEDs which indicate
  power-on and muscle contraction.
• The board was designed with expandability in
  mind a JTAG port was put on the PCB, and a
  prototyping area with through holes was added to
  the front of the robot.

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Stiquito as an Embedded System

• The board in the book will be pre-programmed
  during the manufacturing process.
• The board will make the robot walk in a normal
  fashion without any user programming.
• Advanced users can solder the JTAG port onto the
  board and, using a JTAG interface cable, download
  new code, thus making the board and robot an
  experimental platform.
• The book and accompanying robot (with controller)
  will be an excellent educational device, and
  would not have been possible with the
  full-functioned yet inexpensive MSP430 family of
  microcontrollers.

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Wireless Research
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Research Overview

• Adaptive Antennas
• Performance analysis
• Optimization strategies
• UL band data communication
• Exploit current RF devices
• IEEE 802.11
• Bluetooth
• IEEE 802.15.4
• Optimizing AP Location
• Bandwidth Tradeoffsrange vs. data rate vs.
  reliability
• DSSS Detection
• Synchronization
• Multi User Detection (MUD)

• Wireless Environment

• UL Band Coexistence
• Analysis Methodology
• Mitigation Techniques
• Optimizing Network(s) Performance

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Application Design Considerations
Enabling Application with UL Band Wireless
Device
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Coexistence Summary

• Method for Evaluating Understanding
  Coexistence
• Bluetooth 802.11b
• Arbitrary
• Communication Network
• RF Scenario
• Identify Scenarios Where Coexistence is Impacted
• Methods for Mitigating
• Site Specific Analysis
• Straight Forward Extension to Evaluate other
  WPANs WLANs

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Embedded Wireless Research Test Bed

• IEEE 802.15.4 (Zigbee) is an open specification
  for short-range radio technology that enables
  wireless data communication between devices.
• The 802.15.4 standard was created to further
  reduce power consumption from typical Bluetooth
  devices.
• 802.15.4 devices have a maximum of 20 kbits per
  second in the 868 MHz frequency band and 250
  kbits per second in the 2.4 MHz frequency band.
• Faculty are building competencies in 802.15.4 for
  use in an array of applications, including
  wireless sensor networks.
• Applications include wireless transmission of
  sensed data in geological, environmental, or
  mechanical precision measurement systems.

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Embedded Wireless Research Test Bed

• First deliverable item for this research is an
  embedded wireless communications test bed that
  can be used for future research activities.

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Material Borrowed for this Presentation

• These slides, pictures, etc. have come from many
  sources, too numerous to list fully, but
  including
• Jim Turley (www.jimturley.com)
• Alex Dean (NCSU ECE 306 notes)
• Embedded Systems Programming Magazine
  (www.embedded.com)
• David Stepner, Integrated Systems, Inc.
• Mitsubishi/Renesas
• Electronic Engineering Times

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Contact Information

• James M. Conrad
• Associate Professor
• Dept. of Electrical and Computer Engineering
• UNC-Charlotte
• 9201 University City Boulevard
• Charlotte, NC 28223, USA
• jmconrad_at_uncc.edu
• http//www.ece.uncc.edu/jmconrad
• Phone [phone]
• Fax [phone]
• Preferred method of contact