Embedded operating system

Embedded systems (Embedded system), generally refers to non-desktop computer systems (that is, non-PC, server, small and medium-sized machines, etc.), computer functions and can be "embedded" to special equipment and play a special function of computer equipment or equipment. It is the application-centric, hardware and software can be cut, to adapt to the application system to function, reliability, cost, volume, power consumption and other comprehensive requirements of the special computer system.   　　Simply put, this computer through the electrical connection with the device, and through the computer running on the special program to communicate and control the interface, so that the device becomes an intelligent device, such as: network-based industrial controller, with color display of intelligent terminal. Embedded system mainly by Embedded ProcessorsAs the core hardware system, Embedded Operating systemAnd Application Software Systemsand other components, it is a "device" that can work independently. What is embedded

IEEE (Institute of International Electrical and Electronics Engineers) defines embedded systems as "devices for controlling, monitoring, or assisting in the operation of machines and equipment". The original is: Devices used to control,monitor or Assist the operation of Equipment,machinery or Plants). An embedded system is a dedicated computer system that acts as part of a device or device. UsuallyEmbedded system is an embedded processor control board which is stored in ROM by a control program.。 In fact, all devices with digital interfaces, such as watches, microwaves, VCRs, cars, etc., use embedded systems, some embedded systems also include operating systems, but most embedded systems implement the entire control logic by a single program.1, embedded processor as the core of the hardware systemThe core of embedded system hardware is embedded microprocessor. Embedded microprocessors generally have 3 features: (1) A strong support for real-time and multi-tasking, multi-tasking and short interrupt response time, so that the internal code and real-time operating system execution time is reduced to a minimum, (2) a powerful peripheral general interface extension function,           Can rapidly expand the common hardware interface and achieve communication and control, (3) The power consumption of the embedded microprocessor must be controlled in a small reasonable range, especially for portable wireless and mobile computing and communication equipment battery-powered embedded systems. In the traditional division, many people put such as 8051 8-bit or 16-bit microcontroller also into the embedded system. The reason is that SCM can be "embedded" devices and can be programmed to communicate and control, in line with the functional definition of embedded systems. However, with the development of computer technology, the communication and control of equipment is gradually complex, single-chip microcomputer because generally without operating system, or just use some primary operating system, often can only achieve simple control, for such as file system, communication protocol stack, and GUI these complex applications are often powerless.   　　In many new divisions, it is often not possible to support embedded operating system of the microcontroller excluded from the embedded system. CurrentlyCommon embedded ProcessorsAt present, there are mainly X86 series (such as am186/188, rdc1610c, 386EX, etc.), Power PC series, 68000 series, MIPS series, ARM series (including ARM7, ARM9, ARM11 series) and so on. whichX86 Series because of the compatibility with PC system hardware and software, based on traditional, many industrial control occasions are widely used, and the ARM series, especially the ARM9 series, due to its mature and reliable architecture, the increasingly low cost, a wide range of software systems, in recent years, the rapid development, There is a tendency to form the mainstream embedded system. Light has a core processor, is not able to form an embedded system of the hardware structure. On the basis of the processor core expansion of peripheral circuits, expansion of memory, bus, serial, network and even Io, so as to form a complete computer system can communicate and control the outside world. With the refinement of the division of IT industry, the design and production of such a complete embedded system hardware unit is no longer by the machine manufacturers themselves to complete, but by a number of specialized embedded computer companies to provide, these companies to integrate these necessary hardware on a circuit board, the formation of a factor, Interface full-featured embedded single Board computer. such as the British Chong company X86 series of RDC1610C for the processor core etr232i embedded motherboard, as well as ARM9 series EP9315 for the processor core EM9000 embedded motherboard, at91sam9260 as the core EM9260 embedded motherboard, etc. This is the typical single-board computer, for the user's application, such an embedded motherboard to fully consider the user in a variety of situations need to use the storage space, interface, cost and other factors, better achieve a cost-effective balance, has become a good choice for the end machine users.2. Embedded operating systemIn the traditional partition mode, the embedded operating system can be divided into two categories, one isReal-time operating system for control, communication and other fields, such as WindRiver Company's VxWorks, ISI's PSOS, QNX systems software companies, and ATI Nucleus, the other isnon-real-time operating system, such as Windows CE, Linux, many of these products for consumer electronics products, such as PDAs, mobile phones, set-top boxes, ebooks and so on. However, with the rapid development of the embedded product market, as well as the processing speed and capability of the embedded processor, the so-called non-real-time operating systems such as Windows CE and Linux have made significant improvements in real-time, such as Windows CE5.0, the driver's response delay to hardware interrupts has been less than 50US, while preserving the Windows system's consistent development environment and interface, as well as low development costs, these factors make Windows CE and Linux such as the so-called non-real-time operating system has been industrial control, Communications and other industries widely used, has been booming development.   　　Here, the need for special mention is the traditional single-mission operating system DOS, because the traditional industrial computer long-term use of DOS, in many industrial control situations, DOS is still widely used and running, so many X86 embedded single board computer still running DOS operating system. Or with the company's embedded single Board computer as an example, X86 series embedded motherboards using the traditional DOS operating system, and the use of BC for online development and commissioning, while the ARM9 series motherboards, using the Windows CE operating system, using Microsoft's excellent development tools EVC or VS2005 for development debugging.3. Application software system   Embedded System application software, refers to the use of related software development tools, for customers need embedded systems to achieve the communication or control requirements, to develop and compile, in the relevant hardware platform and embedded operating system running application software.           application software in response to end-user needs, often need to achieve all or part of the following functions:          (1) interface communication: including Ethernet network communication, serial communication, can interface communication, GPRS/CDMA wireless communication and so on         (2) Interface control: such as IO control, bus control, etc.         (3) data acquisition and processing: where the data comes from, where it is stored, how it is handled, where it is transmitted, etc.          (4) Graphical user interface GUI: How the results are displayed to the user in graphical or text interface, and accept the user's instruction   while the user is designing the application software, the biggest challenge is often faced with such as protocol stack, Graphics underlying processing, hardware interface control and many other challenges, if you start from scratch, whether it is technical complexity and the need to spend time and capital costs, are unbearable. So many embedded overall solution providers, such as the British company, not only provide embedded system hardware has been pre-installed operating system, but also provide a full range of low-level driver functions, such as the commercial TCP/IP stack can be run on DOS, can communication protocol, bus control functions, etc., so, Customers only need to focus on their application software itself, can quickly complete product development to form the final product.   There is a need to specifically recommend application software development based on the ARM9 + wince platform. Because of the consistency of the Windows CE system with the Windows system used by the desktop PC, it is possible to use an excellent software platform such as EVC and VS2005 for application development, and any engineer who has used Microsoft software for development can easily get started, using a visual design interface such as MFC GUI interfaces can be easily implemented, and functions such as serial communication and Ethernet communication can be implemented directly using encapsulated classes or functions. In the case of British-created products, it is not only possible to use Windows-rich functions and functions for its development, but also for special interfaces such as Isa, DIO, CAN, and English create the underlying static orDynamic link library, directly call, you can achieve communication and control.   General FW Software, like the Linux kernel, or wince kernel porting (that is, curing into the ROM of the IC), the ROM does not have an OS, the FW software is a single-chip microcomputer (single-chip microcomputer functions single, simple, it is for the realization of certain functions of the Samplecore).   believe that with the further rapid development of computer technology, more and better features of embedded system products will appear in the market, generating more new concepts of digital products, thus affecting our lives.