Embedded systems

1
Embedded systems

• Jonathan Valvano
• http//users.ece.utexas.edu/valvano/
• ENS627
• valvano_at_mail.utexas.edu

• Embedded system demand volume, volume,
• 400 Million units/year automobiles, PCs, cell
  phones
• 30 Million units/year ADSL modems and printers

2
Outline

• Questions about TExaS/EE319K/TRobot
• Future of Embedded Systems
• Choice of an advanced lab
• Introduction to EE345L
• Design example Snake

3
Embedded Systems

• Speech encoder/decoder in cell phones
• Audio decoder in MP3 players
• Audio compensator in a hearing aid
• Image/video encoder in digital still cameras
• Anti-locking braking system
• Engine control system
• Navigation system in autonomous vehicle

4
Embedded Systems Area

• Which courses are most relevant important?
• EE 345M for embedded software
• EE 360R for embedded hardware
• What are important technical challenges today?
• Time-to-market maximizing use of Moores law
• Verification (does it work?) Integration (buy vs
  build)
• What industries/companies need these skills?
• Any company making super high volume products
• How do I prepare for graduate school?
• Take EE 360N Comp. Arch. and EE 360C Algorithms
• Get involved in undergraduate research

5
Signal Processing Applications

• Embedded system demand volume, volume,
• 400 Million units/year automobiles, PCs, cell
  phones
• 30 Million units/year ADSL modems and printers
• Consumer electronics products

Source CEA Market Research (US). Data for 2004
calendar year.
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DSP Processor Market
DSP Processor Market

• DSP chips 22B revenue 05
• DSP processors 34.8 of market
• 17 annual growth predictedfor 2006-2012
• 70 of market based in Texas
• DSP cores/FPGAs rest of market
• Independent processorbenchmarking by industry
• Berkeley Design TechnologyInc.
  http//www.bdti.com
• Embedded MicroprocessorBenchmark
  Consortiumhttp//www.eembc.org
• FAQ http//www.bdti.com/faq

Source Forward Concepts
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Advanced Lab

• EE321K Mixed Signals (DAC and ADC)
• EE440 Integrated Circuits (chip design)
• EE345L Embedded System (Interfacing)
• EE345S Digital Signal Process (math)
• EE362L Power (circuits, conversions)
• EE371C Wireless (communications)
• EE374L Biomedical (electronics, LabView)

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For more information

• EE321K Mixed Signals (Davis)
• EE440 Integrated Circuits (Neikirk)
• EE345L Embedded System (Valvano)
• EE345S Digital Signal Process (Evans)
• EE362L Power (Grady)
• EE371C Wireless (Heath)
• EE374L Biomedical (Rylander, Pearce)

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Embedded Systems

• Take three courses from the following list,
  including at least one course from Group 1 and
  one course from Group 2.
• Group 1 Embedded Hardware
• EE 360M Digital Systems Design Using VHDL
• EE 360R Computer-Aided Integrated Circuit Design
• Group 2 Embedded Software
• EE 345L Microprocessor Applications and
  Organization
• EE 345M Embedded and Real-Time Systems Laboratory
• EE 345S Real-Time Digital Signal Processing
  Laboratory
• EE 360P Concurrent and Distributed Systems
• At Large Courses in Embedded Systems
• EE 360N Computer Architecture

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Embedded Systems Area
Digital Logic
Introduction to
Design
Microcontrollers
(EE 316 FS)
(EE 319K FS)
Microcontroller
Digital
Computer
Applications and
System Design
Architecture
Algorithms
Interfacing
(EE 360M F)
(EE 345L FS)
(EE 360N FS)
(EE 360C FS)
Electives
Real-Time
Computer-Aided
and Embedded
IC Design
Systems
(EE 345M S)
(EE 360R FS)
Concurrent and
Distributed
Systems
(EE 360P S)
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EE345L Microprocessor Applications and
Organization

• Fixed-point conversion
• Debugging with an oscilloscope and a logic
  analyzer
• Design of an alarm clock and LCD I/O driver
• Design of a real-time data acquisition system
• Stepper motor interface
• Design of a music player, DAC, data structure
  design
• Memory interfacing and PCB layout (teams of 6)
• Design of a fixed-point calculator, device
  driver
• Board-level design, construction and testing of a
  complete embedded system

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EE345L design
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EE345M Embedded and Real-Time Systems Lab

• Design of a solid state disk, paged EEPROM memory
  interface, file system, layered software design
• Data acquisition design, analog filter, digital
  filter, spectrum analyzer
• Design of real-time distributed data acquisition
  implementing a controller area network (CAN)
• Real-time operating system, threads, memory
  management, blocking semaphores, queues
• Robot competition (DC motors, servo motor,
  battery circuits, ultrasonic sensors, optical
  sensors, IR sensors, game strategy, leadership,
  design) (teams of 4-6)

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EE345M Robot Competition
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EE345S Real-Time Digital Signal Processing
Laboratory

• digital signal processing signals, sampling,
  filtering, quantization, oversampling, noise
  shaping, and data converters.
• digital communications Analog/digital
  modulation, analog/digital demodulation, pulse
  shaping, pseudo-noise sequences, ADSL
  transceivers, and wireless LAN transceivers.
• digital signal processor architectures Harvard
  architecture, special addressing modes, parallel
  instructions, pipelining, real-time programming,
  and modern digital signal processor
  architectures.

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EE345L Design Objectives

• Appeals to others (fun or useful)
• Easy to use/play (quick to understand)
• Appropriate mix of colors, shapes, sounds
• Market value 5

Embedded System
Microcontroller
Outputs
Inputs
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Requirements

• Use 6811 microcontroller
• PCB layout
• Power supply
• External memory
• I/O device

ROM
6811
Input
Output
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Constraints

• Limited to a set of specific parts
• Can add up to 20 worth of added parts
• 2.5 by 3.8 inch PCB
• All electronics must fit on the PCB
• 3 outputs, 6 In/Out, 11 inputs
• 8K ROM, 512 bytes RAM
• 2 MHz clock

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Design Steps

• Concept Art
• Data flow graph
• Components
• Interfaces
• Testing
• High level Design (the game)
• Prototype
• PCB -gt Mechanical -gt Testing -gt Testing

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Data Flow
Snake Game
Start button
Display
Driver
Game engine
Driver
Driver
Sound
Keypad or Joystick
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LED interface
E
B
PNP -Current flows from E to C -B to E voltage
turns it on PA45V means off PA40V means on
C
NPN -Current flows from C to E -E to B voltage
turns it on PD50V means off PD55V means on
B
C
E
Show PCH and PCB files
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LED display buffer
Field
unsigned char Field44 / 0x00 means off
0x0F means on (snake) 0x0A means fast toggle
for head 0x0C means slow toggle for food /
0A
0F
0C
0F
0F
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Interrupt software design

• Arm (C2I) individually to activate
• Enable (I0)
• Invoke (C2F trigger) only when needed
• ISR runs with interrupts disabled
• ISR has short and bounded execution
• Communicate via shared global memory
• No backward jumps

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LED data structure
Next
Index
Select
Mask
8
3
4
3
2
3
1
3
20
20
20
8
2
4
2
2
2
1
2
10
10
10
8
1
4
1
2
1
1
1
08
08
08
8
0
4
0
2
0
1
0
04
04
04
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LED Software
void RTIHan(void) / every 4.096ms / TFLG2
0x40 / acknowledge RTIF / Row
(PORTA0x80)0x78 / bits6-3 1 / J
Pt-gtIndex M Pt-gtMask if(Field3JM)
Row 0x40 / PA6 / if(Field2JM) Row
0x20 / PA5 / if(Field1JM) Row
0x10 / PA4 / if(Field0JM) Row
0x08 / PA3 / PORTA Row / sets PA6-3,
active low / PORTD Pt-gtSelect Pt
Pt-gtNext FlashCnt-- if(FlashCnt0)
FlashCnt 48 LLPt LLPt-gtnext Pt
LLPt-gtstatept
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Speaker Interface

• Interface considerations
• Impedance-gtcurrent
• Capacitance-gtspeed
• Inductance-gtkickback

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Sound Software
void OC1hndlr(void) if(SoundDuration)
SoundDuration-- / active /
if(SoundPeriodlt10000) PORTA 0x80 /
PA7 sound / if(SoundDuration 0)
if(SongPt) SongPt SongPt-gtNext
if(SongPt) SoundDuration
SongPt-gtDuration SoundPeriod
SongPt-gtPeriod
TOC1 TOC1SoundPeriod TFLG1 0x80 /
acknowledge OC1F /
Next
Period
Duration
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Embedded Systems

• Integration and interfacing
• Timing and synchronization are important
• Large quantity, small size
• Debugging is challenging yet important
• Simulation is an effective design tool
• Power management