EMBEDDED SYSTEMS
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EMBEDDED SYSTEMS
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What is an Embedded System?
Hardware + Software
=
Embedded Systems
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What is an Embedded System?
Software which controls the hardware
A system encapsulated within a large
device to perform a particular task
Is a part of large system
For dedicated applications
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Hardware
Standard components
• Microprocessors, Memory,
Diodes, Etc
System level components
• Sensors, I/O peripherals,
Networking elements.
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Micro Processor versus
Micro Controller
ALU
ACC.
REGISTERS
PC
INT
SP
CLK
MICROPROCESSOR MICRO CONTROLLER
ALU
REG.
ACC.
INT.RAM
SP
INT.ROM
I/O
I/O
INTCLK
PC
UART
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System level components
IR SensorTemperature Sensor
Obstacle Sensor
Gas SensorFinger print Sensor
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I/O Peripherals
GSM MODEMZigBee
GPS
RFID
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Software
High Level Language – User Friendly
Compiler – Easily generate the
machine code
Easy to develop and maintain
Portable
Not necessary to know complete
architecture
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Flow Diagram of Compiler
Linker
Source Code
Preprocessor
Expanded Source Code
Compiler
OBJ Code
EXE
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Compilers and Cross Compilers
Compilers – Coding in one host and
the target is same host
Cross Compilers – Coding in one host
and the target is different
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Cross Compilers List
MPLAB CCS
Code Vision AVR
Keil Micro Vision
Raisonance IDE
Etc….
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Characteristics of Embedded
System
Single-functioned
Tightly-constrained: low cost, low power,
small, fast
Reactive and real-time
Reliable, dependable
Efficient
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Application Areas
Automotive electronics
Avionics
Trains
Telecommunication
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Application Areas
Medical systems: e.g.
• Artificial eye:
Camera attached to glasses with
computer output directly connected
to the brain
Translation into sound with much
better resolution
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Application Areas
Military applications
Authentication
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Application Areas
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Application Areas
Industrial automation
Smart buildings
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Application Areas
Robotics
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“Pipe-climber”Robot
“Johnnie“
(Courtesy
and ©:
H.Ulbrich, F.
Pfeiffer, TU
München)
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Mobile Phones
Multiprocessor
• 8-bit/32-bit
• DSP for signals
• 32-bit in IR port
• 32-bit in Bluetooth
8-100 MB of memory
All custom chips
Power consumption & battery
life depends on software 20
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Mobile Base Station
Massive signal processing
• Several processing tasks per connected
mobile phone
Based on DSPs
• Standard or custom
• 100s of processors
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Telecom Switch
Rack-based
• Control cards
• IO cards
• DSP cards
• ...
Optical & copper connections
Digital & analog signals
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Embedded System Architecture
Usually working in a loop (“hardware
in a loop”):
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A/D converter(sample-and-hold)
Information
processing
display
D/A converter
Sensors Actuators
environment
Embedded system
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Why OS in Embedded Device?
Support for multitasking, scheduling, and
synchronization
Support for a wide range of I/O devices
Support for file systems
Scheduling and buffering of I/O operations
Support for networking
Memory management
Support for graphics displays
Security and Power Management
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OS for Real-Time System
A real-time system must respond to
external inputs and produce new
outputs in a limited amount of time.
The response time needs to be
bounded
General-purpose desktop OS are not
designed for real-time use
• Real-time OS needs to be initially
designed for real-time use in order to
provide fast bounded response times25
EMBEDDED GSM
AUTOMATION
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What is GSM ?
A GSM modem is a wireless modem that works
with a GSM wireless network.
A wireless modem behaves like a dial-up
modem.
The main difference between them is that a dial-
up modem sends and receives data through a
fixed telephone line while a wireless modem
sends and receives data through radio waves.
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GSM: History
Aim : to replace the incompatible analog system
Developed by Group Spéciale Mobile (founded
1982) which was an initiative of CEPT ( Conference
of European Post and Telecommunication )
Presently the responsibility of GSM standardization
resides with special mobile group under ETSI (
European telecommunication Standards Institute )
Under ETSI, GSM is named as “ Global System for
Mobile communication “
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Today many providers all over the world use GSM
(more than 135 countries in Asia, Africa, Europe,
Australia, America)
More than 1300 million subscribers in world and 45
million subscriber in India.
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GSM in World
Figures: March, 2005
37%
1%4%43%
4%
3%
3%
3% (INDIA)
3%
Arab World
Asia Pacific
Africa
East Central Asia
Europe
Russia
India
North America
South America
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VARIOUS AUTOMATIONS USING GSM
GSM/GPRS Automation with Controllers and
PC.
Monitoring Units and PLC Controllers with
GSM/GPRS.
GSM Controller – SMS monitoring with PLC.
GPRS Controller – GPRS real time control with
PLC.
Vehicle Tracking using GPS/SGM/GPRS.
Remote field data logging and control.
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GSM/GPRS AUTOMATION WITH CONTROLLERS
AND PC
The GSM/GPRS concept may be used as it is in
any automation projects and/or suitable parts may
be integrated into any existing systems and
machines for remote automation
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PLC CONTROLLERS WITH GSM/GPRS.
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GSM Services
Tele-services
Bearer or Data Services
Supplementary services
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Tele Services
Telecommunication services that
enable voice communication
via mobile phones
• Offered services
Mobile telephony
Emergency calling
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Bearer Services
Include various data services for information transfer between GSM and other networks like PSTN, ISDN etc at rates from 300 to 9600 bps
Short Message Service (SMS)
up to 160 character alphanumeric data transmission to/from the mobile terminal
fax
Voice mailbox
Electronic mail
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Supplementary Services
Call related services :
• Call Waiting- Notification of an incoming call while on the handset
• Call Hold- Put a caller on hold to take another call
• Call Barring- All calls, outgoing calls, or incoming calls
• Call Forwarding- Calls can be sent to various numbers defined by the user
• Multi Party Call Conferencing - Link multiple calls together
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GSM Operation
Speech decoding
Channel decoding
De-interleaving
Burst Formatting
De-ciphering
DemodulationModulation
Ciphering
Burst Formatting
Interleaving
Channel Coding
Speech coding
Radio Interface
Speech Speech
13 Kbps
22.8 Kbps
22.8 Kbps
33.6 Kbps
33.6 Kbps
270.83 Kbps
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Outgoing Call
1. MS sends dialled number to BSS 2. BSS sends dialled number to
MSC3,4 MSC checks VLR if MS is
allowed the requested service. If so, MSC asks BSS to allocate resources for call.
5 MSC routes the call to GMSC6 GMSC routes the call to local
exchange of called user7, 8,9,10 Answer back(ring back) tone is
routed from called user to MS via GMSC,MSC,BSS
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Incoming Call
1. Calling a GSM subscribers2. Forwarding call to GSMC3. Signal Setup to HLR4. 5. Request MSRN from VLR6. Forward responsible MSC to
GMSC7. Forward Call to current MSC8. 9. Get current status of MS10.11. Paging of MS12.13. MS answers14.15. Security checks16.17. Set up connection
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GSM modem
o Wireless modem
o Like GSM mobile, GSM modem
requires a SIM card
o Behaves like dial-up modem
o Modem sends and receives through
radio waves.
o Dial-up use a fixed telephone line.
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GSM modem
A GSM modem can be a dedicated modem device
with a serial, USB or Bluetooth connection, or it may
be a mobile phone that provides GSM modem
capabilities
The basic segregation of working of the modem is
as under:
• Voice calls
• SMS
• GSM Data calls
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APPLICATIONS
Remote control switching of vehicle
engine pre-heaters
Remote control switching of irrigation
systems, water well pumps and pumping
stations
Automated gate remote control
Remote control lighting
Security systems
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AT commands
AT commands are instructions used to control a
modem.
AT is the abbreviation of ATtention.
Every command line starts with "AT" or "at“.
Commands are usually followed by at least a
minimal response of: “OK” if the command line has
been executed successfully or “ERROR” if the
command line has errors or is not executed
successfully.
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AT commands
To call
ATD phone number;
To send message
AT+CMGS=“ phone number”
message
ctrl+Z
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AT commands
To receive message
AT+CNMI=2,2,0,0,0
To read message
AT+CMGR
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Types of GSM
Types of GSM and band used in the frequency
spectrum
GSM 850
GSM 900
GSM 1800
GSM 1900
The number indicates the frequency band, in MHz,
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Applications
• Automatic Meter Reading
• GSM Pay Phones
• Traffic management
• Remote data logging and reporting
• Security systems
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Advantages of GSM over Analog
system
Capacity increases
Reduced RF transmission power and longer battery
life.
International roaming capability.
Better security against fraud (through terminal
validation and user authentication).
Encryption capability for information security and
privacy.
Compatibility with ISDN,leading to wider range of
services
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Future Of GSM
2nd Generation
GSM -9.6 Kbps (data rate)
2.5 Generation ( Future of GSM)
HSCSD (High Speed ckt Switched data)
Data rate : 76.8 Kbps (9.6 x 8 kbps)
GPRS (General Packet Radio service)
Data rate: 14.4 - 115.2 Kbps
EDGE (Enhanced data rate for GSM Evolution)
Data rate: 547.2 Kbps (max)
3 Generation
WCDMA(Wide band CDMA)
Data rate : 0.348 – 2.0 Mbps
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Thank youby,
Focus Tech MediaNo.3, Gem Plaza, II Floor,
SRC Road, Trichy-2.Off: +91 431-4544 142. Mob: 90030 10012/14.
E-Mail Id: [email protected]
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