02-06-2012, 04:53 PM
EMBEDDED SYSTEMS
EMBEDDED SYSTEMS.doc (Size: 50.5 KB / Downloads: 36)
ABSTRACT:
The need to carry out some specific tasks by using hardware and software made the advent of embedded systems. This paper presents and analyses the requirements, various categories of embedded system and also the development process and the hardware architecture ,operating systems. Applications smart- cards encryption devices GPS receivers is studied and scope of future advancements are highlighted.
INTRODUCTION:
Man’s immense case to find new things for making life as comfortable as possible lead to the invention of many new things like radio, television, telephone etc.. and at one stage leading to the invention of computers .this invention has changed the life of many completely and made world enter into a new phase of technology. this invention brought into light many fields which are bringing the unimaginable things at the door step of common man. One such field is ”EMBEDDED ENGINEERING “. It resulted some wonderful products such as remote control, watches ,computers ,phones ,video graphics through rings and many more exemplary products.” An embedded system can be described as one consisting of a processor associated peripherals and software used for a specific purpose.” Ex: VCR:- Specific task is to record and play video cassettes. Their hardware and software are designed to carry out this specific task only. “An Embedded system is a combination of hardware and Software.”
CATEGORIES OF EMBEDDED SYSTEMS :-
A. Stand alone Embedded system.
B. Real time Embedded systems.
STANDALONE EMBEDDED SYSTEMS:
Works in a standalone mode, taking input and producing output.
INPUT : Electrical signals from sensors or commands from humans.
OUTPUT : Electrical signals to drive other systems.
Ex1 : For process control in manufacturing units.
Ex2 : Automobiles.
REALTIME EMBEDDED SYSTEMS :
These are required to carryout specific tasks in specified amount of time.
Ex1: A System that has to open a value within 30ms when the humidity crosses particular threshold.
Ex2: If the job is not carried out within the 30ms period a catastrophe may ensure.
MOBILE DEVICES:
As the advent of wireless network that can support very high special mobiledevices and capable of supporting high data rate services in addition to voice services. Accessing internet services like E-MAILS,WORLD WIDE WEB and so one can be done while a person is on the move. Such devices need to run a powerful mobile operating system and download information from websites.
Ex: Many such devices are Java Enabled.
PROCESS OF EMBEDDED SYSTEMS DESIGN & DEVELOPMENT:
A. Determine the requirements of the Embedded system .
B. Design the architecture.
C. Select the operating system.
D. Choose the processor and associated peripherals.
E. Choose the development platform.
F. Code the application and optimize the code according to guidelines.
G. Verify the software of the host system.
H. Verify the software of the target system.
HARDWARE ARCHITECTURE:
An Embedded system is built around a processor there by all the computations are done by the CPU with the help of input taken from various external devices.
--PROCESSOR: Processor can be of three types:
a. Microcontroller
b. Microprocessor
c. Digital signal processor.
--MEMORY: It is of two types one in internal and other is external.
--INTERNAL MEMORY: It is found in same silicon as processor .The advantage is the high cost .The advantage is its less programming , swapping resulting in fast instruction and data accessing.
--EXTERNAL MEMORY: Instead of storing the programs and data in the internal memory we can use memory chips to processor.These are RAM &ROM.
--SECONDARY MEMORY: Hard disks , floppy disks , CD-ROM’S are secondary storage devices.
--SECONDARY STORAGE DEVICES: High end operating systems and applications software require very logic programs and virtual memory. Such requirements are driving the industry to introduce secondary storage on some Embedded device such as Industrial automation systems , Mobile devices etc.
-- MEMORY MODEL BEING USED EXTENSIVELY: In coming days the memory can be as to become more popular in the near future .The processor writes directly to the flash chip, making the data transfer much faster.
--APPLICATION UNDER USE:
A. Handheld computers
B. Smart cards
-- OTHER HARDWARE DEVICES: The hardware devices which are using are
--LATCHES AND BUFFERS: These chips hold the processor output data to be sent to the external devices.
--CRYSTAL: CPU needs a clock source and a crystal oscillator generates the clock.
--RESET CIRCUIT: To take care of any unforeseen problems like software hang-ups ,power supply failures.
--CHIP SELECT LOGIC CIRCUIT: It is used to identify uniquely a particular chip with which transactions are to be made.
--APPLICATION SPECIFIC CONTROL CIRCUITRY: Embedded systems are extremely diverse various devices needed include sensors and transducers, relays and various input devices are all controlled by this circuitry.
--DISPLAY UNITS: Some Embedded systems does not need omly display devices. Ex: Unmanned space craft , process control sub systems. Embedded systems that require user interaction must have display units which can be either liquid crystal displays or LED’S.
--KEYPAD: Some Embedded systems offer different capabilities for providing user input. Ex: Handheld computers : Full pledged qwerty keyboard or a form of handwriting recognition .Some embedded systems require only a function keypad to perform a limited number of operations.
--COMMUNICATION INTERPHASES: To interact with external devices
Ex: Mobile phones, handheld computers.
--PROGRAMMABLE LOGIC DEVICES: It is a single chip in which a large amount of discrete logic and memory can be combined in order to reduce the size of Embedded system. Suppliers of these chips are :
ACTEL,ADAPTIVE,SILICON,ACTERA
DEVELOPMENT TOOLS:
NEED: Embedded software on the host system is needed to transfer the program on to a memory chip on the target processor board. For this we need few development tools like
EEPROM PROGRAMMER: To transfer data into the memory devices.
EEPROM ERASER: To erase the contents of an EEPROM chip.
SIGNATURE VALIDATORS: Devices are available that can compute the CRC .Using the standard CRC algorithms ,and then store that signature on the chip. These devices are called “Signature validators”.
EMBEDDED SOFTWARE DEVELOPMENT TOOLS:
ENVIRONMENTS: The landscape of embedded software development has changed drastically as availability of operating systems targeted for Embedded systems .Odd techniques for code reuse resulting in faster environments.
OPERATING SYSTEMS: The Embedded software has to interact with the hardware to get the desired functionality. This interaction consists of efficiency managing the input output operations. The memory ,the various tasks to be carried out ,and the resources to do the specific tasks needed to obtain the desired response.
TYPE OF OPERATING SYSTEMS:
A.NON REAL TIME OPERATING SYSTEM: There OS do not provide hard real time functionality. In other words ,if strict deadlines are to be met ,there OS are not suitable.
B. REAL TIME OS: There OS provide the necessary system calls to achieve real time dead lines.
C.MOBILE /HANDHELD OS: OS that are fine tuned to work in environment are known as ‘Mobile/Handheld OS’.
PROGRAMMING LANGUAGES: Embedded systems use different processors depending on performance requirements and cost .Each processor has its own instruction set ,writing the software for target processor requires your learning the corresponding assembly language instruction set .
ASSEMBLY LANGUAGES: In assembly languages, each statement represents one machine instructions and programs have to deal with low level details , such as register allocation and procedure calling sequences, therefore hardware knowledge is required to do programming in assembly language .More over the assembly language is dependent on processor used .It is very difficult to write and maintain large programs written in assembly language as they are very lengthy.
C.C++,JAVA:C is a high level language with a lot of functionality for low level programmes to directly access the hardware through programs and the operating system can be accessed through functions calls. Compilers are available for every processor and these compilers produce compact and efficient code. In addition a large proof of C programs are available .For these reasons C is the most widely used language for Embedded software development.
EMBEDDED VISUAL TOOLS: Microsoft ‘s embedded visual tools can be used to develop embedded application very fast ,using your knowledge of application development for desktop in VB and VC++. embedded visual tools provide IDE to develop application for a WINDOWS CE operating system that runs on handheld computers such as handheld PC, pocket PC and PC1.2.
BREW: Qwalconm’s binary run time environment for wireless(brew) SDK facilitates the development of mobile data application for wireless memory less based on CODE DIVISION MULTIPLIERS: CDMA TECHNOLOGY.
APPLICATIONS OF EMBEDDED SYSTEM:
Embedded systems are found in a variety of consumer electronics (such as cell phones , pagers, digital cameras etc),home appliances(micro wave ovens ,thermostats etc),business equipment(cash registers, card readers etc),automobiles(transmission control, fuel injection ,active suspension etc).One might say that nearly any device that runs on electricity has or will soon have a computing system embedded in it.
PREDICTIVE FAN FAILURE CIRCUIT:
The TC670 is the industry’s first predictive fan failure integrated circuit.A single resistor divider is adequate for setting the RPM alarm level and implementing predictive fan failure without the need for software.Eliminating the need to purchase more expensive and often custom-made- 3-wire fans,the space-saving SOT-23 package has the ability to detect critical fan speed (RPM) OF 2-wire and 3-wire fans and provide thermal Failure protection in temperature-sensitive equipment
.
The device is able to predict fan failure by sensing fan revolutions and asserting a logic-low alert signal whenever the fan speed falls below a user programmable trip point.The TC670 has a pin for clearing the alert signal,making it ideal for interfacing with microcontrollers .Hardware-based programmability allows for flexability of design,since different systems utilize fans that run at different RPM levels,and reliability.Small size and low operating current (90 mA typical) make the TC 670 ideal for space and power critical systems.The TC670 also features high RPM detection accuracy as well as the ability to monitor multiple fans in parallel.This accuracy,flexability,and software-free means of implementation significantly reduces the complexity and cost of predictive fan failure detection and therefore provides a superior, easy-to-use solution for equipment utilizing active cooling methods.Applications targeted for the TC670 device include telecom and networking equipment,power supplies,instrumentation,data storage equipment,notebooks and servers,industrial control and general purpose fan-fault detection.
MEDICINE:
High Definition Imaging systems provide doctors with exceptional insights into the workings of human anatomy.Such systems allow a doctor to view minute variances in tissue
Texture,thus increasing the quantity and quality of diagnostic information.Emedded systems can be found at the heart of these technologies.
Transtelephonic Pacemaker Moniters allow for instantaneous diagnosis of cardiac symptoms over standard telephone lines in accordance with patient specific parameters programmed into the unit’s microcomputer by the patient's doctor,these products will continuously moniter the patient’s cardiac activity,provide early detection of ventricular tacharrhythmias,and automatically (through electrodes attached to the patient’s chest )transmit electrical charges to the patient’s heart to terminate the arrhythmia.
FUTURE TRENDS IN EMBEDDED SYSTEMS:
SYSTEM ON CHIP: Instead of using separate chip for the processors and associated circuits ,techniques can now build a single IC that contains the complete functionality of an embedded system.We can build an entire system on a single chip.
This SOC concepts is not now,but only recently has the technology matured to a stage where you can except many common items such as
Digital wrist watch
Reducing in cost and size
SOC IN HOME:
Except all the electronic gadgets at your homes and offices to become computer that can communicate with one another.We can enable these appliances and control them from a desktop across the INTERNET or can control them through a device of our choice such as mobile phones.
Advances in sensor technologies are also leading to interesting developments such as development of electronic noise(e-noise ) and electronic eye (e-eye).
SMART CARDS AND CASHLESS SOCIETY:
Smart card technology is bringing about revolutionary changes and people are starting to use these because of reliability of their embedded hardware and software.
Credit card sized electronic system containing embedded processing element and memory for applications as storing a patient’s health record.Security and authentication information and soon.
EMBEDDED SYSTEMS
EMBEDDED SYSTEMS.doc (Size: 50.5 KB / Downloads: 24)
Def1: They are computing systems with tightly coupled hardware and software integration, designated to perform a specific function
Def2: They are devices used to control, monitor or assist the operation of equipment, machinery or plant.
Characteristics of an embedded system:
is a digital system.
uses a microprocessor or a microcontroller.
runs on software for some or all of its functions.
frequently used as a controller
MICROPROCESSOR BASED SYSTEM (COMPUTER)
It is divided into three parts namely CPU, Memory and I/O.
The function of CPU is to execute information stored in memory
I/O devices enable the users to communicate with the CPU.
The CPU is connected to memory and I/O through strips of wire called a bus.
The bus carries information from place to place inside a computer
HOW A COMPUTER STARTS
When a computer BIOS program is loaded into CPU RAM.
It detects other I/O devices like Keyboard and mouse and secondary memory(Hard Disk) by sending test data and reports error if not found.
The hard disk has Boot loader in its starting address which has information regarding the number and type of Operating System
Operating system manages and shares resources
and acts as a launch pad for various softwares
CREATING UC BASED APPLICATIONS
It involves the following tasks
Power distribution
System clocking
Interface design and wiring
Application programming
Device Programming
EMBEDDED SYSTEMS.doc (Size: 50.5 KB / Downloads: 36)
ABSTRACT:
The need to carry out some specific tasks by using hardware and software made the advent of embedded systems. This paper presents and analyses the requirements, various categories of embedded system and also the development process and the hardware architecture ,operating systems. Applications smart- cards encryption devices GPS receivers is studied and scope of future advancements are highlighted.
INTRODUCTION:
Man’s immense case to find new things for making life as comfortable as possible lead to the invention of many new things like radio, television, telephone etc.. and at one stage leading to the invention of computers .this invention has changed the life of many completely and made world enter into a new phase of technology. this invention brought into light many fields which are bringing the unimaginable things at the door step of common man. One such field is ”EMBEDDED ENGINEERING “. It resulted some wonderful products such as remote control, watches ,computers ,phones ,video graphics through rings and many more exemplary products.” An embedded system can be described as one consisting of a processor associated peripherals and software used for a specific purpose.” Ex: VCR:- Specific task is to record and play video cassettes. Their hardware and software are designed to carry out this specific task only. “An Embedded system is a combination of hardware and Software.”
CATEGORIES OF EMBEDDED SYSTEMS :-
A. Stand alone Embedded system.
B. Real time Embedded systems.
STANDALONE EMBEDDED SYSTEMS:
Works in a standalone mode, taking input and producing output.
INPUT : Electrical signals from sensors or commands from humans.
OUTPUT : Electrical signals to drive other systems.
Ex1 : For process control in manufacturing units.
Ex2 : Automobiles.
REALTIME EMBEDDED SYSTEMS :
These are required to carryout specific tasks in specified amount of time.
Ex1: A System that has to open a value within 30ms when the humidity crosses particular threshold.
Ex2: If the job is not carried out within the 30ms period a catastrophe may ensure.
MOBILE DEVICES:
As the advent of wireless network that can support very high special mobiledevices and capable of supporting high data rate services in addition to voice services. Accessing internet services like E-MAILS,WORLD WIDE WEB and so one can be done while a person is on the move. Such devices need to run a powerful mobile operating system and download information from websites.
Ex: Many such devices are Java Enabled.
PROCESS OF EMBEDDED SYSTEMS DESIGN & DEVELOPMENT:
A. Determine the requirements of the Embedded system .
B. Design the architecture.
C. Select the operating system.
D. Choose the processor and associated peripherals.
E. Choose the development platform.
F. Code the application and optimize the code according to guidelines.
G. Verify the software of the host system.
H. Verify the software of the target system.
HARDWARE ARCHITECTURE:
An Embedded system is built around a processor there by all the computations are done by the CPU with the help of input taken from various external devices.
--PROCESSOR: Processor can be of three types:
a. Microcontroller
b. Microprocessor
c. Digital signal processor.
--MEMORY: It is of two types one in internal and other is external.
--INTERNAL MEMORY: It is found in same silicon as processor .The advantage is the high cost .The advantage is its less programming , swapping resulting in fast instruction and data accessing.
--EXTERNAL MEMORY: Instead of storing the programs and data in the internal memory we can use memory chips to processor.These are RAM &ROM.
--SECONDARY MEMORY: Hard disks , floppy disks , CD-ROM’S are secondary storage devices.
--SECONDARY STORAGE DEVICES: High end operating systems and applications software require very logic programs and virtual memory. Such requirements are driving the industry to introduce secondary storage on some Embedded device such as Industrial automation systems , Mobile devices etc.
-- MEMORY MODEL BEING USED EXTENSIVELY: In coming days the memory can be as to become more popular in the near future .The processor writes directly to the flash chip, making the data transfer much faster.
--APPLICATION UNDER USE:
A. Handheld computers
B. Smart cards
-- OTHER HARDWARE DEVICES: The hardware devices which are using are
--LATCHES AND BUFFERS: These chips hold the processor output data to be sent to the external devices.
--CRYSTAL: CPU needs a clock source and a crystal oscillator generates the clock.
--RESET CIRCUIT: To take care of any unforeseen problems like software hang-ups ,power supply failures.
--CHIP SELECT LOGIC CIRCUIT: It is used to identify uniquely a particular chip with which transactions are to be made.
--APPLICATION SPECIFIC CONTROL CIRCUITRY: Embedded systems are extremely diverse various devices needed include sensors and transducers, relays and various input devices are all controlled by this circuitry.
--DISPLAY UNITS: Some Embedded systems does not need omly display devices. Ex: Unmanned space craft , process control sub systems. Embedded systems that require user interaction must have display units which can be either liquid crystal displays or LED’S.
--KEYPAD: Some Embedded systems offer different capabilities for providing user input. Ex: Handheld computers : Full pledged qwerty keyboard or a form of handwriting recognition .Some embedded systems require only a function keypad to perform a limited number of operations.
--COMMUNICATION INTERPHASES: To interact with external devices
Ex: Mobile phones, handheld computers.
--PROGRAMMABLE LOGIC DEVICES: It is a single chip in which a large amount of discrete logic and memory can be combined in order to reduce the size of Embedded system. Suppliers of these chips are :
ACTEL,ADAPTIVE,SILICON,ACTERA
DEVELOPMENT TOOLS:
NEED: Embedded software on the host system is needed to transfer the program on to a memory chip on the target processor board. For this we need few development tools like
EEPROM PROGRAMMER: To transfer data into the memory devices.
EEPROM ERASER: To erase the contents of an EEPROM chip.
SIGNATURE VALIDATORS: Devices are available that can compute the CRC .Using the standard CRC algorithms ,and then store that signature on the chip. These devices are called “Signature validators”.
EMBEDDED SOFTWARE DEVELOPMENT TOOLS:
ENVIRONMENTS: The landscape of embedded software development has changed drastically as availability of operating systems targeted for Embedded systems .Odd techniques for code reuse resulting in faster environments.
OPERATING SYSTEMS: The Embedded software has to interact with the hardware to get the desired functionality. This interaction consists of efficiency managing the input output operations. The memory ,the various tasks to be carried out ,and the resources to do the specific tasks needed to obtain the desired response.
TYPE OF OPERATING SYSTEMS:
A.NON REAL TIME OPERATING SYSTEM: There OS do not provide hard real time functionality. In other words ,if strict deadlines are to be met ,there OS are not suitable.
B. REAL TIME OS: There OS provide the necessary system calls to achieve real time dead lines.
C.MOBILE /HANDHELD OS: OS that are fine tuned to work in environment are known as ‘Mobile/Handheld OS’.
PROGRAMMING LANGUAGES: Embedded systems use different processors depending on performance requirements and cost .Each processor has its own instruction set ,writing the software for target processor requires your learning the corresponding assembly language instruction set .
ASSEMBLY LANGUAGES: In assembly languages, each statement represents one machine instructions and programs have to deal with low level details , such as register allocation and procedure calling sequences, therefore hardware knowledge is required to do programming in assembly language .More over the assembly language is dependent on processor used .It is very difficult to write and maintain large programs written in assembly language as they are very lengthy.
C.C++,JAVA:C is a high level language with a lot of functionality for low level programmes to directly access the hardware through programs and the operating system can be accessed through functions calls. Compilers are available for every processor and these compilers produce compact and efficient code. In addition a large proof of C programs are available .For these reasons C is the most widely used language for Embedded software development.
EMBEDDED VISUAL TOOLS: Microsoft ‘s embedded visual tools can be used to develop embedded application very fast ,using your knowledge of application development for desktop in VB and VC++. embedded visual tools provide IDE to develop application for a WINDOWS CE operating system that runs on handheld computers such as handheld PC, pocket PC and PC1.2.
BREW: Qwalconm’s binary run time environment for wireless(brew) SDK facilitates the development of mobile data application for wireless memory less based on CODE DIVISION MULTIPLIERS: CDMA TECHNOLOGY.
APPLICATIONS OF EMBEDDED SYSTEM:
Embedded systems are found in a variety of consumer electronics (such as cell phones , pagers, digital cameras etc),home appliances(micro wave ovens ,thermostats etc),business equipment(cash registers, card readers etc),automobiles(transmission control, fuel injection ,active suspension etc).One might say that nearly any device that runs on electricity has or will soon have a computing system embedded in it.
PREDICTIVE FAN FAILURE CIRCUIT:
The TC670 is the industry’s first predictive fan failure integrated circuit.A single resistor divider is adequate for setting the RPM alarm level and implementing predictive fan failure without the need for software.Eliminating the need to purchase more expensive and often custom-made- 3-wire fans,the space-saving SOT-23 package has the ability to detect critical fan speed (RPM) OF 2-wire and 3-wire fans and provide thermal Failure protection in temperature-sensitive equipment
.
The device is able to predict fan failure by sensing fan revolutions and asserting a logic-low alert signal whenever the fan speed falls below a user programmable trip point.The TC670 has a pin for clearing the alert signal,making it ideal for interfacing with microcontrollers .Hardware-based programmability allows for flexability of design,since different systems utilize fans that run at different RPM levels,and reliability.Small size and low operating current (90 mA typical) make the TC 670 ideal for space and power critical systems.The TC670 also features high RPM detection accuracy as well as the ability to monitor multiple fans in parallel.This accuracy,flexability,and software-free means of implementation significantly reduces the complexity and cost of predictive fan failure detection and therefore provides a superior, easy-to-use solution for equipment utilizing active cooling methods.Applications targeted for the TC670 device include telecom and networking equipment,power supplies,instrumentation,data storage equipment,notebooks and servers,industrial control and general purpose fan-fault detection.
MEDICINE:
High Definition Imaging systems provide doctors with exceptional insights into the workings of human anatomy.Such systems allow a doctor to view minute variances in tissue
Texture,thus increasing the quantity and quality of diagnostic information.Emedded systems can be found at the heart of these technologies.
Transtelephonic Pacemaker Moniters allow for instantaneous diagnosis of cardiac symptoms over standard telephone lines in accordance with patient specific parameters programmed into the unit’s microcomputer by the patient's doctor,these products will continuously moniter the patient’s cardiac activity,provide early detection of ventricular tacharrhythmias,and automatically (through electrodes attached to the patient’s chest )transmit electrical charges to the patient’s heart to terminate the arrhythmia.
FUTURE TRENDS IN EMBEDDED SYSTEMS:
SYSTEM ON CHIP: Instead of using separate chip for the processors and associated circuits ,techniques can now build a single IC that contains the complete functionality of an embedded system.We can build an entire system on a single chip.
This SOC concepts is not now,but only recently has the technology matured to a stage where you can except many common items such as
Digital wrist watch
Reducing in cost and size
SOC IN HOME:
Except all the electronic gadgets at your homes and offices to become computer that can communicate with one another.We can enable these appliances and control them from a desktop across the INTERNET or can control them through a device of our choice such as mobile phones.
Advances in sensor technologies are also leading to interesting developments such as development of electronic noise(e-noise ) and electronic eye (e-eye).
SMART CARDS AND CASHLESS SOCIETY:
Smart card technology is bringing about revolutionary changes and people are starting to use these because of reliability of their embedded hardware and software.
Credit card sized electronic system containing embedded processing element and memory for applications as storing a patient’s health record.Security and authentication information and soon.
EMBEDDED SYSTEMS
EMBEDDED SYSTEMS.doc (Size: 50.5 KB / Downloads: 24)
Def1: They are computing systems with tightly coupled hardware and software integration, designated to perform a specific function
Def2: They are devices used to control, monitor or assist the operation of equipment, machinery or plant.
Characteristics of an embedded system:
is a digital system.
uses a microprocessor or a microcontroller.
runs on software for some or all of its functions.
frequently used as a controller
MICROPROCESSOR BASED SYSTEM (COMPUTER)
It is divided into three parts namely CPU, Memory and I/O.
The function of CPU is to execute information stored in memory
I/O devices enable the users to communicate with the CPU.
The CPU is connected to memory and I/O through strips of wire called a bus.
The bus carries information from place to place inside a computer
HOW A COMPUTER STARTS
When a computer BIOS program is loaded into CPU RAM.
It detects other I/O devices like Keyboard and mouse and secondary memory(Hard Disk) by sending test data and reports error if not found.
The hard disk has Boot loader in its starting address which has information regarding the number and type of Operating System
Operating system manages and shares resources
and acts as a launch pad for various softwares
CREATING UC BASED APPLICATIONS
It involves the following tasks
Power distribution
System clocking
Interface design and wiring
Application programming
Device Programming