Cross-cutting and integration of the pillar disciplines of embedded systems

1 A brief history of embedded systems

1.1 The Birth of Embedded Systems

Embedded systems were born in the era of microcomputers. After a brief exploration of embedded specialization of microcomputers, it entered the era of independent microcontroller development of embedded systems. Single-chip microcomputers with processor cores developed directly on the basis of embedded processors and peripheral integrated circuit technology, that is, intelligent electronic systems of microcontrollers. Even if there is a processor core, it is an embedded processor rather than a general-purpose microprocessor. The following uses Figure 1 to explain that embedded systems are not special-purpose computers.

Figure 1 The birth, exploration and development of embedded systems

Modern computers are microcomputers born on the basis of microprocessors. After the birth of microcomputers, they quickly walked out of the computer room with their small size, low price and high reliability, triggering the demand for intelligent control of large electromechanical equipment. It is required to embed microcomputers into large electromechanical equipment to take on the intelligent control of large electromechanical equipment. Such microcomputers become special-purpose computers embedded in specific electromechanical systems. In order to distinguish them from general-purpose computer systems, this special-purpose computer is called an "embedded computer system." Starting from the fact that the concept of embedded systems was born from microcomputers, it can be considered that embedded systems are special-purpose computer systems in the early days.

1.2 The failed exploration of special-purpose computers

After the birth of embedded systems, in order to meet the most extensive embedded application requirements of the target system, the application model of embedded systems has been continuously explored. In the early days, they were developed according to the idea of ​​industrial computers, single-board computers, and microcomputers of special-purpose computers.

Industrial computers are microcomputers that have been mechanically and electrically reinforced. As embedded systems, they cannot meet the basic requirements of embedded systems: small size, extremely low price, high reliability, and good object coupling. Subsequently, board-level microcomputers (single-board computers) appeared, which reduced the size of computers and lowered the price, and quickly set off a wave of intelligent transformation of traditional electronic systems.

Neither industrial computers nor single-board computers can completely meet the requirements of small size, extremely low price, and high reliability of embedded systems. People simply simplified the microcomputer architecture and integrated it into a semiconductor chip to make a single-chip microcomputer. Motorola's 6801 series is a single-chip microcomputer integrated by simplifying the 6800 series microcomputer. The single-chip microcomputer completely solves the extremely small size and extremely low price of embedded systems, but there is no essential improvement in high reliability and object controllability. Foreign countries call chip-based microcomputers Single Chip Microcomputers.

As an embedded application of industrial control, high reliability and object coupling are crucial, and it has jumped out of the application requirements of traditional computers. For example, embedded systems have regarded "crash" and "real-time" as important technical issues from the beginning, and the bus, interface, and system configuration that are electrically connected to the object system as important technical development directions. Therefore, embedded systems must get rid of the shackles of "special computers" and take the independent "microcontroller" path. Practice has proved that the development path of industrial computers, single-board computers, and single-chip special computers based on general microcontrollers is not feasible. [page]

1.3 Independent Development Path of Embedded Systems

The development path of microcontrollers (MCUs) in embedded systems is a path to independent development by getting rid of the shackles of "dedicated computers". This is a path of independent development of MCUs opened up by Intel MCS51 MCU and iDCX51 real-time multitasking operating system. MCS51 is an original embedded processor based on microelectronics and integrated circuits and in accordance with embedded application requirements. MCS51's original architecture, control-type instruction system and Boolean space, external bus mode, and special function register (SFR) management mode have laid the foundation for the hardware structure of embedded systems; iDCX51 is a real-time multitasking operating system specially configured with MCS51 MCU to meet the requirements of embedded applications.

MCS51 ushered in the era of single chip microcomputers, which are the independent development of embedded systems. This is the era of microcontrollers. Foreign countries promptly and accurately changed the name of "Single Chip Microcomputer" to "Microcontroller Unit". This is not a word game.

As embedded systems enter the era of single-chip microcomputer development, the most important technology development hotspots are expansion buses and communication buses that fully meet the requirements of embedded applications; real-time requirements of software; sensor interfaces, servo drive interfaces, human-machine interfaces and communication interfaces connected to the object system; clock systems, power management systems and low-power modes that meet the requirements of low-power management; interrupt systems that can meet multiple state incentives, etc.

In the era of single-chip microcomputers, embedded systems were mainly used for the intelligent transformation of traditional electronic systems, forming an application era for semiconductor manufacturers and object system electronic engineers. More precisely, the single-chip microcomputer application system is an intelligent modern electronic system.

Due to the widespread application of embedded systems and the various supports provided by semiconductor integrated circuits, DSP and PLD solutions have emerged in the field of embedded systems (see Figure 1). DSP highlights signal processing functions and is combined with embedded processors to become an important branch of embedded systems; PLD provides solutions for gate array semi-customized embedded application systems and has formed two major branches: SoPC and FPGA/CPLD. Regardless of the direction of technical development, SoC is the unified affiliation of embedded application systems.

At present, denying the concept of dedicated computers for embedded systems has important practical significance. It is conducive to the correct positioning and cross-integration of the four pillar disciplines in embedded systems.

2 Four pillars of embedded systems

At present, embedded systems have not yet formed an independent discipline system. From the birth of "embedded systems", the independent development path of single-chip microcomputers, the connotation of microcontroller technology development, and the various solutions of embedded systems, "embedded systems" is the intersection and integration of four pillar disciplines, and the discipline positioning and division of labor are carried out in a platform mode.

2.1 Diagram of the relationship between the four pillar disciplines

The four pillar disciplines of embedded systems are microelectronics, computer science, electronic technology, and object science, and their relationship is shown in Figure 2. Microelectronics is the foundation for the development of embedded systems, object science is the destination discipline for embedded system applications, and computer science and electronic technology are important guarantees for the development of embedded system technology.

Figure 2: Intersection and integration of the four pillar disciplines of embedded systems

2.2 Leading Microelectronics Discipline

The leading role of microelectronics and semiconductor integrated circuits is that they provide the integrated circuit foundation for the application of embedded systems. Many important achievements of electronic technology and computer science will eventually be reflected in integrated circuits, from early digital circuit integration to today's analog-digital hybrid, software/hardware combination, and IP-based knowledge and knowledge behavior integration. [page]

2.3 Computer science serving the platform

After the emergence of modern computers, two major branches of computer science have been formed, namely general computer science and embedded computer science. General computer science and embedded computer science have different technical development directions and technical connotations. Since embedded computer science is closely related to object science and microelectronics, and embedded computer science is quite different from the original computer science, the concept of general computer cannot be used to interpret embedded systems. Therefore, embedded computers should strengthen communication with microelectronics, electronics, and object science, and jointly undertake the task of building a new discipline of embedded systems.

In embedded systems, computer science is responsible for building embedded system application platforms, which include the integrated development environment for embedded systems, computer engineering methods, programming languages, and programming methods.

2.4 Electronic technology disciplines with extensive services

In embedded systems, the electronic technology discipline provides the most extensive technical services. Electronic technology has rapidly developed integrated circuit design in the field of microelectronics from circuit integration, function integration, and technology integration to knowledge integration; it provides hardware design technical support for embedded systems for computer science; in the target discipline, a large number of application engineers have realized the most extensive applications on embedded software and hardware platforms.

2.5 The ultimate solution for object disciplines

Object discipline is the end-user discipline of embedded systems. Object discipline covers almost all scientific and technological fields, forming an infinite application field for embedded systems. So far, embedded system experts no longer answer the question "Where are embedded systems used?"

For the target discipline, the embedded system is just an intelligent tool. The target discipline needs to build an embedded application system in the field on the embedded system. The technical basis of the embedded application system is the basic theory, application environment and application requirements of the discipline. At the same time, in the application, technical requirements should be constantly put forward to the disciplines of microelectronics, integrated circuit design and embedded computers, so as to continuously improve the technical level of the embedded system platform.

3 Disciplines under the platform model

The division of labor platform model is the basic development model of industry and technology in the knowledge economy era. All knowledge innovation and innovative knowledge application must follow the platform development path.

3.1 Origin of the platform model

The platform model is a basic industry and technology model in the knowledge economy era. It is an inevitable phenomenon when the separation and integration laws of human knowledge develop to a higher level. It transforms the integrated industry and technology model into a platform model under the medium of the knowledge platform. If you compare the radio industry in the 1960s with the VCD/DVD industry in the 1990s, you will find the essential difference between the integrated industry model and the platform industry model.

In the 1960s, all enterprises in the radio industry, without exception, undertook the entire process from creativity, product development, prototype design, prototype production, to mass production, following a closed integrated industrial model. In the VCD/DVD era of the 1990s, an industrial model of social division of labor between semiconductor manufacturers and township enterprises emerged: semiconductor manufacturers transformed VCD/DVD ideas into VCD/DVD software and hardware kits, township enterprises purchased VCD/DVD software and hardware kits, and realized mass production of VCD/DVD machines with the technical support of semiconductor manufacturers. Semiconductor manufacturers never produce VCD/DVD machines, and township enterprises never engage in VCD/DVD technical research. VCD/DVD software and hardware kits are the knowledge platform of VCD/DVD technology. With the knowledge platform as the center, the social division of labor between the knowledge industry and the manufacturing industry has been realized. The knowledge industry engages in knowledge innovation, transforms the results of knowledge innovation into knowledge platforms, and does not engage in the final application of knowledge results; the manufacturing industry completes the final application of innovation results based on the knowledge platform.

3.2 Platform Model of Embedded Systems

According to the law of knowledge development, knowledge innovators do not engage in knowledge application, and knowledge application personnel do not need to understand the principles of innovative knowledge; according to the law of integrated development, knowledge innovators should integrate innovative knowledge results into tools and transform them into knowledge platforms, and knowledge application personnel should realize innovative knowledge application based on knowledge platforms. [page]

In the early embedded systems, integrated circuit chips (single-chip microcomputers and peripheral circuits) and development devices were application platforms provided by semiconductor manufacturers to users, and electronic engineers in the target field completed the application of embedded systems on such platforms. At present, embedded systems supported by the four pillar disciplines will inevitably form an industry and scientific research ecosystem that develops according to the platform model.

The target discipline is the end user of the embedded system, and the electronic technology application engineers in the target discipline should implement the embedded application system design on a ready-made embedded system platform.

Microelectronics, embedded computer, and electronic technology disciplines (application engineers in non-target disciplines) are not end users of embedded systems. The important task of these disciplines is to transform innovative scientific and technological achievements into various knowledge platforms. For example, integrated circuits in the microelectronics field provide advanced MCU, peripheral chips, SoC and other IC platforms; embedded computer disciplines provide integrated development environments, programming languages, algorithms, and computer engineering method platforms; electronic engineers cooperate with microelectronics design, embedded computer disciplines, and OEM manufacturers to complete product platforms for embedded systems and provide technical services for product platforms.

From the perspective of platform, an excellent embedded system product must be developed based on an excellent embedded system platform.

3.3 Discipline positioning and division of labor under the platform model

Since embedded systems have the interdisciplinary characteristics of four pillar disciplines, each discipline will reflect its strengths and weaknesses in embedded systems. Therefore, there is a problem of discipline positioning and cross-integration in embedded systems. "Discipline positioning" is reflected in each discipline using its own disciplinary advantages and intervening in the development of embedded systems on the basis of its own discipline; "cross-integration" is based on discipline positioning, constantly understanding the technical development requirements of other disciplines for embedded systems, so as to build the best knowledge platform for embedded systems and realize the best embedded system applications.

Due to the cross-integration of various disciplines, the team building of each discipline should absorb a certain proportion of personnel from other disciplines on the basis of its own discipline. For example, in recent years, a lot of embedded application system design talents have been absorbed in the field of integrated circuit design; when the embedded system major was established in the computer college of colleges and universities, many application-oriented talents in embedded systems in the target field were introduced.

The positioning of the four pillar disciplines in embedded systems, in addition to the positioning of the discipline knowledge structure, must also reflect the positioning in the knowledge platform model. The positioning of this platform model is a 3+1 positioning. That is, the microelectronics discipline, computer discipline, and electronic technology discipline build various types of application platforms for embedded applications, without intervening in the specific application of embedded systems; the object discipline must realize the product application of embedded systems in the field of this discipline based on the embedded system application platform, and does not need to intervene in the platform construction of embedded systems. For example, as far as embedded operating systems are concerned, the construction of operating systems should be positioned in the field of computer science, but to build an excellent embedded operating system, it is necessary to understand the application characteristics and application environment of embedded systems, and at the same time be able to foresee the firmware trend in future MCU chips; in the object field, the operating system is regarded as a tool, and only the performance and application interface of the operating system need to be understood; microelectronics technology experts must understand the characteristics of embedded operating systems and application software, so that chip technology can be incorporated into integrated circuit design after reaching a certain stage.

Embedded systems are an infinitely large space. Whether it is embedded system platform construction or embedded system platform application, there is unlimited room for development. The key is to grasp one's own "positioning" and "division of labor" and understand the "intersection" and "integration" of disciplines.

References

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[3] He Limin. Multidisciplinary integration and penetration centered on SoC [J]. Microcontrollers and Embedded Systems Application, 2001(5).