ABSTRACT:
This paper attempts to investigate the approach of embedded systems. The embedded system is a combination of computer hardware, software and perhaps additional mechanical or other parts, designed to perform a specific function within a given time frame.
INTRODUCTION:
An embedded system is a special-purpose computer system built into a larger device .An embedded-system is typically required to meet very different requirements than a general-purpose personal computer Two major areas of differences are cost and power consumption. Since many embedded systems are produced in the tens of thousands to millions of units range, reducing cost is a major concern. Embedded systems often use a (relatively) slow processor and small memory size to minimize costs.
Some of the attributes of the coming era:
- The number of smart devices ( i.e., products with embedded operating systems inside ) will grow exponentially, reaching numbers in the billions.
- The choice of CPU will be more a matter of cost than technology or a architecture
- Nearly all devices will have connectivity, whether wired or wireless.
- Most devices will have the ability to be upgraded or repaired remotely, by downloading new firmware or software.
Most devices will have specific rather than general-purpose functionality, so their users application software will be defined by the manufactures (rather than loaded by their). This needs to, “minimize cost and maximize specialization”creates the opportunity for embedded systems.
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Embedded systems are becoming all pervasive. Every microwave has one. A cellular hand phone has two. A luxury Mercedes car has around 40. The latest Boeing 777-302,will have tens of dozens-we’re talking about the ubiquitous microprocessor chips and their associated peripheral devices.
To cite other examples, embedded software allows your washing machine to choose speed according to the type of cloth, gives thinking power to the microwave, acts like a music conductor in the car engine and pushes rocket launchers into space. The embedded system generally comprises topics like real time embedded digital signal processing, microprocessor architecture programming concepts; Real-time Operating System (QXN, RT Linux, V x Works); Micro controllers; Embedded Systems Programming Data Communication Networking, C concepts and linux among others.
START UP:
All embedded systems have start-up code. Usually it disables interrupts, sets of up the electronics, tests the computer (RAM, CPU and software), and then starts the application code. Many embedded systems recover from short-term power failures by skipping the self-tests if the software can prove they were done recently. Restart times under a tenth of a second are common.
‘Embedded systems’ has come to mean “micro-controller programming”. With the increasing proliferation of embedded systems, and advances in hardware and software technologies and the blurring of the boundary between them we need a more meaning-ful glimpse into this area. “Embedded systems’ addresses this need and brings out the issues in building modern-embedded systems.
DESIGN OF EMBEDDED SYSTEMS
The electronics usually uses either a microprocessor or a microcontroller some large are old systems use general-purpose mainframe computers are mini computers. Embedded systems design is getting complex, requiring intimate knowledge of both the hardware and software worlds. Cramming all those chips in a square centimetre of silicon real estate is more an art then a science. Getting the software to work with limited memory is often a struggle. Designers embedded systems strive to improve performance, reliability and cost effectiveness. Hardware and software choices are simultaneously considered. This is called co-design.
The goal is to produce an efficient implementation that satisfies-performance and cost requirements on the design the entire system on a chip-the SOC approach. Information appliances can be fabricated from custom SOC silicon .This has been successful in designing cellular hand phones where the high volume usually dictate this design strategy.
CHARACTERISTICS :
Two major areas of differences are cost and power consumption . Since many embedded systems are produced in the tens of thousands to millions of units range, reducing cost is a major concern. Embedded systems often use a (relatively) slow processor and small memory size to minimize costs.
The slowness is not just clock speed. The whole architecture of the computer is often intentionally simplified to lower costs.
For example embedded systems often use peripherals controlled by synchronous serial Interfaces, Which are ten to hundreds of times slower than comparable peripheral used in PCs. Programs on an embedded systems often must run with real time constrains with limited hard ware resources:
Often there is no disk drive, operating system , keyboard or screen. A flash drive may replace rotating media and a small keypad and LCD screen may be used instead of a PCs keyboard and screen. Firmware is the name for software that is embedded in hardware devices, e.g. in one or more ROM memory IC chips .
PLATFORM:
There are many different CPU architecture used in embedded designs. This in contrast to the disk top computer marke-t, which as of this writing (2003) is to limited just a few competing architectures , chieply intel’s x86,and the apple/Motorola/IBM power PC, used in the apple macintosh.
One common configuration for embedded system is the system on a chip, an application specific integrated circuit, for which the CPU was purchased as intellectual property to add to IC’s design.
