The retrieval report on the embedded IntroductionWith the development of information technology, we've gone through the PC era, experiencing the network era, which faces the so-called post-pc Generation to generation.At present, due to the family network and Internet, make consumer electronics, computer, communications (3c) tend to be more integrated, from the people in life to use a mobile phone, PDA, TV, refrigerators and other civil electronic and communication products, to missile, satellite communications, submarines and other military control core, all marked by ES (Embedded system).While in the post-pc era, information home appliances, a new generation of mobile phones and intelligent building more indispensable new applications such as the core technology.This article from the basic concept of embedded type system, key technologies and development prospect of the three parties face embedded type system were introduced.1 The basic concept of embedded system1.1 The definition of embedded systemThe British association of electrical engineers for embedded system is to define like this: "embedded type system to control, monitor, or auxiliary equipment, machines, and even the factory operating device".Embedded type system must meet the following four characteristics: perform a specific function;Based on the microprocessor and its peripheral;Strict timing and high stability;Fully automatic cycle operation.It is a comprehensive computer software and hardware, and special emphasis on the principle of "tailored", that is, based on a kind of special purpose, for the purpose to develop a specific system, the so-called customization.In the emerging of embedded type system products, common has a mobile phone, PDA, GPS, Set a top box or embedded type server and thin terminals , etc.1.2 The typical composition of the embedded systemEmbedded system is a set of software and hardware can be independent at an organic whole, meet the specific application of firmware.1.2.1 Hardware systemThe diversity of the hardware platform of embedded type system, some small system only 1 K of data space, 16 K application empty, and some high-performance systems such as working frequency up to 1 GHz 64 - bit systems, the FLASH MEMORY of 32 M, 128 M SRAM, it shall be decided by the particular application goal.But the typical embedded system hardware part includes microprocessor, memory, and peripheral devices and 1/0 port, the graphics controller, etc.Is different with general computer systems, it is generally not as large as a hard disk capacity of the storage medium, and often use an EPROM, EEPROM or flash memory as a storage medium.1.2.2 Software systemEmbedded type software system is mainly composed of embedded operating system (EOS) of type and embedded application of type two parts.One type of the operating system is still a difference of filling-in hardware, unified system for each application interface, memory management, renService scheduling control.And we know the general operating system (such as MS - window series) is different, because of limited capacity itself with ROM, usually do is small, a minimum of 10 a 20 K.Embedded type application is on the basis of the EOS application specific task, operation and behavior of the control system.However, the embedded type system itself does not have the ability to develop bootstrap, users to realize the secondary development must have a set of development tools and environment.2 The characteristics of embedded system2.1 Characteristics of embedded systemCompared with general computer technology industry presents the phenomenon of monopoly, embedded system is different, it is a highly fragmented industry not monopoly, there is no a series of processor and operating system can all monopoly market.Even if there is major in architecture, but the diversity of applications made impossible to have a few companies, a few products all monopoly market.So products and technologies in the field of embedded system, and small and medium-sized high-tech companies for various industries development space is very large.2.2 the characteristics of the embedded system productsEmbedded system and the concrete application is close together, it's upgrading is a synchronization carry on, and the specific products.The embedded type system once products into the market, has a longer life cycle.Embedded type system of software, usually curing in read-only memory, rather than on disk as the carrier, can be replaced, so the application of embedded type system software life cycle and embedded type also as long as the product.Software of embedded type system more emphasis on inheritance and bridging technology, relatively stable development.The development of embedded processors also reflects the stability of a system should exist commonly 一10 8 years.A system structure and its associated peripherals, development tools, library functions, embedded application products is a complex knowledge system, users and semiconductor manufacturers will not easily give up a processor.2.3 The characteristics of embedded system softwareOne type of processor is key to realizing the function of the embedded system application software, the embedded processor system software and should be Using software requirements are different and the general computer.Main features are: software requirements solid-state storage;High quality, high code Reliability;High real time capability of the system software;Need real-time multitasking operating system development platform.3 The key technology of embedded systemThe key technologies of embedded systems including chip technology, software technology, communication, computer network technology and fieldbus technology And so on, these technologies to promote the development of the embedded system upgrading, to raise the level of intelligence, popularize application of breadth, depth of evolution.3.1 chip technologyThe core component of embedded type system are the various types of embedded processors, at present, according to incomplete statistics, decay processors, microcontrollers and DSP embedded people all over the world has more than 1000 kinds of varieties of total popular architecture have thirty several series, one type of processor addressing space generally from 64 KB to 16 MB, MIPS processing speed from 0.1 to 2000 MIPS, commonly used packaging from 8 pins to 144 pins.AMD X86 series, for example, Intel Pentium, strong Ann series, Texas Instruments of TMS320 series and Motorola DSP56000 series, etc.3.2 Embedded software technologyIn order to satisfy the application upgrade function, the designers on the one hand, a more powerful embedded type processor, such as making a, 64 a RLSC or signal processor DSP chip to enhance processing capacity;Also USES the real-time multitasking programming technology and cross development tools to control the functional complexity, simplify application design, ensuring software quality and shorten the development cycle, namely for embedded software technology.Mainly including embedded operating system, embedded database, embedded Web browser, embedded software development platform and tools.One of the most core is embedded real-time operating system (RTOS).(WIN9x) with PC operating system, embedded operating system does not require one type all-powerful, but must be able to according to the system design specifications, effectively perform the computing power of hardware, to achieve optimal efficiency and low cost products and most complete set system will require full automatic, such as factories or bank system in addition to the original cultivated for a long time in the field of embedded people type VxWORK, QNX, Nucleus, and so on, the emerging of its main products include Palm OS, Windows CE, Linux, etc.4 The embedded system development prospects4.1 NetworkIn order to adapt to one type distribution processing structure and application of the Internet, the embedded type system requirements of the 21st century is equipped with one or more network communication interface standard.Requirements for external network, embedded devices must be equipped with communication interface, corresponding to the TCP/IP protocol suite software support;Because the householdelectrical appliances (such as interconnected anti-theft alarm, lighting energy control, film and television equipment and information exchange information terminal) field instrument and the coordination work requirements, such as the new generation of embedded type equipment also need to have the IEEE 1394, USB, CAN, Bluetooth or IrDA communication interface, at the same time also need to provide the corresponding communication network protocol software and the physical drive software.4.2 Small size, low-power and low costEmbedded micro controller processor as the core of information home appliances products, the demands of portability and wireless, makes people in the exam Quantity, more focused on embedded people declined the processor's power consumption rather than performance.Now already not to evaluate treatment with speed Machine but with the power to evaluate processor time, at the same time, power transmission and energy consumption has become a performance and integration.The major limitation.In order to meet the demands on the one hand, embedded type product designers corresponding degrade the performance of the processor, limited memory capacity and reuse interface chip.On the other hand, the progress of the integrated circuit process and the development of the hardware itself, makes this possible.But software technology progress than hardware, it's appropriate to improve the technical requirements for embedded software design.4.3 humanizedIn today's information age, how to deal with huge amounts of information, allow the user to obtain the needed information, because the simplified operation is one of the challenges faced by embedded devices.People and information interaction terminal GUI screen centered multimedia interface.Handwritten text input, voice dial-up Internet access, email and color graphics, images have already achieved initial results.At present, some advanced PDA has Chinese characters on the display screen writing, voice short message posted, but there is a great distance from palm language simultaneous translation.These depend on people of artificial intelligence and the further research in the field of biological science and technology information.All in all, try to reduce to the threshold of the user, to making a fool of.。