Transcript Characteristics of Embedded Systems

Embedded Systems
A “short list” of embedded systems
Anti-lock brakes
Auto-focus cameras
Automatic teller machines
Automatic toll systems
Automatic transmission
Avionic systems
Battery chargers
Camcorders
Cell phones
Cell-phone base stations
Cordless phones
Cruise control
Curbside check-in systems
Digital cameras
Disk drives
Electronic card readers
Electronic instruments
Electronic toys/games
Factory control
Fax machines
Fingerprint identifiers
Home security systems
Life-support systems
Medical testing systems
Modems
MPEG decoders
Network cards
Network switches/routers
On-board navigation
Pagers
Photocopiers
Point-of-sale systems
Portable video games
Printers
Satellite phones
Scanners
Smart ovens/dishwashers
Speech recognizers
Stereo systems
Teleconferencing systems
Televisions
Temperature controllers
Theft tracking systems
TV set-top boxes
VCR’s, DVD players
Video game consoles
Video phones
Washers and dryers
And the list goes on and on
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Characteristics of Embedded Systems
• single functioned
• tightly constrained design matrix
• reactive & real time
Hardware Architecture of Embedded System
Development Flow
Design Matrix
• Nonrecurring Engineering Cost (NEC)
• Unit cost
see later
• Size ( physical, memory, #gates #transistors)
Will be addressed in a separate presentation called “What is ASIC”
• Performance (execution time, latency,
throughput)
• Power
• Time to Prototype see later
• Time to Market
see later
• Maintainability
NRE and unit cost metrics
• Compare technologies by costs -- best depends on quantity
– Technology A: NRE=$2,000, unit=$100
– Technology B: NRE=$30,000, unit=$30
– Technology C: NRE=$100,000, unit=$2
$200,000
B
C
$120,000
$80,000
$40,000
A
B
$160
p er p rod uc t c ost
tota l c ost (x1000)
$160,000
C
$120
$80
$40
$0
$0
0
800
1600
2400
Numb er of units (volume)
• But, must also consider time-to-market
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$200
A
0
800
1600
2400
Numb er of units (volume)
Time-to-market
• Time required to develop a
product to the point it can
be sold to customers
• Market window
Revenues ($)
– Period during which the
product would have highest
sales
Time (months)
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• Average time-to-market
constraint is about 8
months
• Delays can be costly
Losses due to delayed market entry
• Simplified revenue model
Peak revenue
Peak revenue from
delayed entry
Revenues ($)
On-time
Market fall
Market rise
Delayed
– Product life = 2W, peak at W
– Time of market entry defines a
triangle, representing market
penetration
– Triangle area equals revenue
• Loss
D
On-time
entry
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Delayed
entry
W
2W
Time
– The difference between the
on-time and delayed triangle
areas
Processor Technology
General Processor
( e.g. Microprocessor)
Single Purpose Processor
(e.g. Digital Signal Processor or Digital Controller)
Application Specific Processor (ASIP)
Processor Technology
• General Processor (GP)
- concentrate on software development
- favourable NEC, time to prototype & maintainability
• Single Purpose Processor (SPP)
- concentrate on hardware
- favourable performance, power, size & unit cost
• Application Specific Processor (ASIP)
– optimised for a particular class of applications (e.g.
microcontroller, DSP) a compromise between GP and SPP.
IC Technology
Full Custom: VLSI (Very Large Scale Integration), full mask
needed, high NEC, long turn-round time.
Semi-Custom (Gate Arrays and Standard Cell) also called
ASIC (Application Specific IC) Mask needed for
interconnections.
FPGA: Connections configured programmatically
FPGA Smallest “Brick” =Logic Cell
FPGA = matrix of many THOUSANDS Logic Cells
Interconnections are configured by the User
Example:Interconnect of Carry Signals
IO Cells Connect Logic Cells to the Pins
FPGAs have also On Chip RAM
Dual Port RAM
Last Slide:
Implementation
• Discrete Design on PCB
• System On Chip (SOC)
will be done in Workshops !!!