Embedded system application technology
This paper introduces the meaning, development, present situation and opportunities of embedded system in China, focuses on the hardware of embedded system, and briefly explains the embedded operating system.
Single chip microcomputer; Microcomputer; Operating system; Linux embedded system
1. Definition and market prospect of embedded system
Embedded system refers to a special computer system with application as the center and computer technology as the basis, which can be tailored in software and hardware to meet the strict requirements of application system for function, reliability, volume and power consumption. It is mainly composed of embedded microprocessor, peripheral hardware devices, embedded operating system and application software, and is used to control, monitor and manage other devices.
PC is mainly used in the field of office automation, and embedded system has penetrated into people's work and life, such as industrial control, traffic management, information appliances, home intelligent management system, POS network and e-commerce, environmental monitoring, robotics and other fields. Today, the annual industrial output value brought by embedded systems has exceeded 65,438+0 trillion dollars. A report of the American Embedded System Conference pointed out that all-digital TV products based on embedded computer systems will generate a new market of10.5 trillion US dollars every year in the United States in the next five years. The senior manager of Ford, the American automobile king, also declared? Ford sold it? Computing power? Has surpassed IBM? From this, we can imagine the scale and breadth of the embedded calculator industry. 1998 1 1 embedded internet based on RTOS has become a new technology hotspot at the embedded system conference held in California, USA. Negroponte, a famous American futurist, predicted during his visit to China in June 1999 that embedded intelligent (computer) tools would be the greatest invention after personal computers and the Internet in four to five years. This is the so-called? Post-PC era? Concept.
2. The development stage of embedded system
Embedded system has been around for more than 30 years. In recent years, the convergence trend of computer, communication and consumer electronics has become increasingly obvious, achieving the trend of 3C convergence. Throughout its development process, it has gone through several stages.
The first stage is a programmable controller (PLC) system with single chip microcomputer as the core, which has the functions of monitoring, servo and indicating equipment. Most of these systems are used in some professional industrial control systems. Without the support of operating system, they are only programmed and controlled by assembly language.
The second stage is based on single chip microcomputer (also known as MCU microcontroller unit). At this time, the programming language changed from assembly to C. At present, there are many kinds of MCU with low price, and it still plays an important role.
The third stage is an embedded system marked by embedded operating system. At this time, the speed of single chip microcomputer is getting faster and faster, and its functions are getting more and more. At this time, the software mainly runs on the embedded operating system. The embedded operating system can run on various types of single-chip computers with good compatibility. The user interface is friendly, there are a large number of application program interface APIs, and the development and application are simple.
The fourth stage is the embedded system marked by the Internet. With the development of Internet and the increasing integration of Internet technology with information appliances and control technology, embedded systems are increasingly combined with the Internet through various bus forms.
3. Core hardware of embedded system
The core hardware of embedded system is single chip microcomputer, also known as MCU. It is a kind of microcomputer, which miniaturizes the basic components of the computer and integrates them into a chip. Generally, the chip includes CPU, ROM, RAM, parallel I/O, serial I/O, timer/counter, interrupt control, system clock and system bus. With the development of technology, the function of on-chip integration of single chip microcomputer is becoming more and more powerful, and it is developing in the direction of SoC(System on chip). Single-chip microcomputer has obvious advantages such as small size, low power consumption, strong function, high cost performance and easy popularization and application, and has been widely used in automation devices, intelligent instruments, process control, communication, household appliances and many other fields.
At present, according to incomplete statistics, the total number of embedded processors in the world has exceeded 1000, and there are more than 30 popular architectures, of which 805 1 accounts for the majority. There are more than 20 semiconductor manufacturers producing 805 1 single chip microcomputer, and there are more than 350 kinds of derivative products. Generally, according to the number of bits in the data bus of single chip microcomputer, single chip microcomputer is divided into 4-bit, 8-bit, 16-bit and 32-bit computers.
3. 1 four-bit single chip microcomputer. Four-bit single chip microcomputer is suitable for all kinds of small household appliances. General SCM manufacturers have their own four-bit SCM products, including MSM64 164C from OKI Company, MSM6448 1 from NEC Company and 75006 from NEC Company. Series, SMC62 series of Epson company, etc.
Typical application fields include: input devices for PC (mouse, joystick), battery chargers (nickel-cadmium batteries, lithium batteries), sports equipment, audio and video product controllers with LCD displays, control and remote control of general household appliances, toy control, timers, clocks, watches, calculators, multifunctional telephones and LCD game machines.
3.2 Eight-bit MCU. Eight-bit single-chip microcomputer is the most abundant and widely used single-chip microcomputer at present, which has obvious advantages such as small size, low power consumption, strong function, high cost performance and easy popularization and application. At present, it is mainly divided into MCS-5 1 series and its compatible models and non-MCS-5 1 series single chip microcomputer.
The compatible products of MCS-5 1 have advantages because of their complete development tools and software and hardware resources. ATMEL, Philips and Winbond are established manufacturers of MCS-5 1 single chip microcomputer, and CYGNAL and ST have also introduced new products, among which the new model of ST? PSD series chips have many advanced functions, such as high-capacity FLASH( 128/256KB), 8/32KB SRAM, integrated A/D, watchdog, power-on reset circuit, bidirectional UART, ISP programming in support system and IAP programming in application, etc. , was quickly accepted by the majority of 5 1 single chip computer users. CYGNAL introduced the 5 1 series single chip microcomputer C805 1F series Soc. Integrated A/D D/A circuit, watchdog, power-on reset circuit, I C, SPI, CAN bus, FLASH technology, JTAG simulation debugging, up to 100MIPS.
Non-5 1 series microcontrollers are widely used in China, including MOTOROLA68HC05/08 series, PIC microcontroller of MICROCHIP and AVR microcontroller of ATMEL.
Eight-bit single chip microcomputer has been widely used in automation devices, intelligent instruments, process control, communication, household appliances and many other fields.
3.3 Sixteen-bit MCU. The performance of 16-bit single chip microcomputer is greatly improved compared with that of 8-bit computer. At present, the main products are INTEL's MCS-96/ 196 series, TI's MSP430 series and Motorola's 68HC 1 1 series.
Sixteen-bit single chip microcomputer is mainly used in industrial control, intelligent instruments and meters, portable equipment and other occasions. Among them, the MSP430 series of TI is widely used in low power occasions because of its ultra-low power consumption.
3.4 32-bit MCU. 32-bit MCU is the development trend of MCU. With the development of technology and the decrease of development cost and product price, it will keep pace with the 8-bit computer. There are as many manufacturers of 8-bit computers as there are manufacturers of 32-bit single-chip computers. Motorola, Toshiba, Hitachi, NEC, Epson, Mitsubishi and Samsung, among which 32-bit ARM single chip microcomputer and Motorola's MC683 and 68K series are widely used. MCU based on ARM core occupied 75% of the 32-bit MCU market in 200 1 year.
3.5 the development of single chip microcomputer technology. It can be seen from the development of single chip microcomputer in the past 20 years that the development of single chip microcomputer technology is guided by the development of microprocessor (MPU) technology and VLSI technology, and driven by a wide range of application fields, showing the following technical characteristics.
8-bit and 32-bit single chip microcomputer develop together. This is another trend of the development of single chip microcomputer technology. For a long time, the development of single chip microcomputer technology is mainly based on 8-bit computers. With the mobile communication, network technology, multimedia technology and other high-tech products entering the home, the application of 32-bit single chip microcomputer has developed rapidly.
The speed of single chip microcomputer is getting faster and faster. In order to improve the anti-interference ability of single chip microcomputer, it is the pursuit of single chip microcomputer technology development to reduce noise and clock frequency without sacrificing operation speed. Some 805 1 single chip compatible manufacturers have improved the internal timing of single chip microcomputer, and the operation speed has been greatly improved without increasing the clock frequency. Motorola single chip microcomputer adopts phase-locked loop technology or internal frequency doubling technology, which makes the internal bus speed much higher than the clock generator frequency. 68HC08 single chip microcomputer adopts 4.9MHz external oscillator, and its internal clock reaches 32M. Samsung Electronics recently launched Halla, the core of 1.2GHz ARM processor.
Low voltage and low power consumption. Almost all single-chip computers have power-saving operation modes such as waiting and stopping. The allowable power supply voltage range is also wider and wider. Generally, single-chip microcomputer can work in the range of 3 ~ 6V, and battery-powered single-chip microcomputer no longer needs to take voltage stabilization measures for power supply. The lower limit of low-voltage single-chip microcomputer power supply has been reduced from 2.7V to 2.2V and1.8V. The single-chip microcomputer with 0.9V power supply has come out.
Low noise and high reliability technology. In order to improve the anti-electromagnetic interference ability of single chip microcomputer system, make products adapt to harsh working environment and meet the requirements of higher standards in electromagnetic compatibility, various single chip microcomputer manufacturers have adopted some new technical measures in the internal circuit of single chip microcomputer. Like ST company? The watchdog timer is added to PSD series single chip microcomputer, and the anti-EMI circuit is added to the COP8 single chip microcomputer of NS, which enhances the? Watchdog? The performance of.
ISP and IAP. In system programming and application programming, the microcontroller is programmed by programming lines, serial data and clock lines. It is shared with I/O line, and there is no need to add additional pins of microcontroller. ISP provides convenience for development and debugging, which makes remote debugging and upgrading of single chip microcomputer system a reality.
4. Embedded system software
The software of embedded system has gradually developed from the initial assembly language to the advanced C language, and now it has finally formed an operating system, with dozens of products, such as VxWorks, QNX, Nucleus,? C/OS, Palm OS, Windows CE and Linux series. Technically, it has the following characteristics.
(1) thinks that there are more and more new processors, and the design of embedded system is easier to transplant, thus supporting a variety of microprocessors in a short time.
(2)Linux products have been widely used in embedded systems. Linux has stable performance, good tailoring, easy development and use, and is suitable for a variety of embedded processors. Linux has been supported by many manufacturers, and RT-Linux products have made great progress. It has great potential in household appliances and industrial control.
5. Develop and apply China's independent embedded system technology.
At present, the architecture of PC is controlled and monopolized by Wintel. In this field, now we have no initiative and there is little room for innovation. Experts estimate that it is difficult to make a breakthrough in ten years. However, there is no unified architecture for embedded systems, and various combinations of software and hardware are needed, which is technology-intensive and has a large market capacity. China has unlimited room for innovation in this field. Like what? Starlight China Core Project? Is it the first time to use digital multimedia chips as a breakthrough? China Core Starlight No.1? Strategic projects that take the lead in entering the international market are in a leading position in the world. It has always been in a leading position in this field. In the field of operating system, are there any products launched by ChinaSoft? Soft real-time embedded Linux operating system? It can respond to external interrupts at microsecond level and provide precise real-time control, concurrent operation and synchronization mechanism for real-time tasks and threads.
6. Concluding remarks
The above introduces the meaning of embedded system, its development history, hardware and embedded operating system. Finally, the opportunities faced by China in embedded system are summarized, which can provide reference for further research on embedded system and help people in this field.
Did you get a look at him? Embedded technology paper? People still see:
1. Research paper on application development of embedded system based on C/OS
2. The application of 2.JNI technology in embedded software development.
3. Thesis of Computer Science and Technology
4. The complete set of electronic technology model essays.
5. Microcontroller technical paper