With the rapid development of IT technology, the internet has entered the era of the "Internet of Things" (IoT). The IoT requires a large number of devices that no longer rely on human-to-human interaction for connection, but rather connect through protocols, communication, and programming. The goal of the IoT is to endow all objects with computer-like intelligence, but not in the form of general-purpose computers, and to connect these "smart" objects to the network. This requires the support of embedded technology. Embedded technology is an application of computer technology that primarily designs dedicated computer systems—embedded systems—for specific applications.
Embedded systems are application-centric, computer technology-based systems with customizable hardware and software. They are suitable for specialized computer systems with stringent requirements for functionality, reliability, cost, size, and power consumption. Embedded systems are typically embedded within larger physical devices and remain unnoticed. Examples include control components in mobile phones, PDAs, and even air conditioners, microwave ovens, and refrigerators. Devices connected to the internet, such as the one described below, all contain embedded computer systems, but we may not normally even notice their existence.
Embedded technology differs from general-purpose computer technology. We know that general-purpose computers are mostly used to interact with people and work according to human instructions; while embedded systems may autonomously process events they "perceive" in most cases, so they have higher requirements for timeliness and reliability.
Generally speaking, embedded systems should have the following characteristics: specialization, encapsulation, real-time performance, and reliability.
Specialization refers to the fact that embedded systems are designed for specific devices to perform specific tasks, unlike general-purpose computer systems which can perform a variety of different tasks.
Encapsulation refers to the fact that embedded systems are generally hidden inside the target system and are not noticed by the operator. Real-time performance refers to the ability of an embedded system to respond to events or user intervention within a predictable timeframe compared to the frequency of actual external events.
Reliability refers to the fact that embedded systems are hidden within systems or devices, and once they start operating, they may operate for extended periods without human monitoring or maintenance, thus requiring reliable operation. Like general-purpose computer systems, embedded systems consist of both hardware and software. Hardware includes the processor/microprocessor (what we commonly call the CPU), memory, peripheral devices, input/output ports, graphics controllers, etc. The software includes the operating system software and application software specifically designed to solve certain problems. Sometimes designers combine these two types of software; the application program controls the system's operation and behavior, while the operating system controls the interaction between the application program and the hardware.
Embedded computer systems have the following characteristics compared to general-purpose computer systems:
1. Embedded systems are usually designed for specific applications. The biggest difference between embedded CPUs and general-purpose CPUs is that embedded CPUs mostly work in systems designed for specific user groups. They usually have the characteristics of low power consumption, small size, and high integration. They can integrate many tasks that are performed by boards in general-purpose CPUs into the chip, which is conducive to miniaturization of embedded system design, greatly enhances mobility, and makes the coupling with the network increasingly tighter.
2. Embedded systems are products that combine advanced computer technology, semiconductor technology, and electronic technology with specific applications in various industries. This inherently determines that they are technology-intensive, capital-intensive, highly decentralized, and constantly innovating knowledge integration systems.
3. Both the hardware and software of embedded systems must be designed efficiently, tailored to the specific needs, and unnecessary and redundant functions should be removed to strive for the same performance on a smaller silicon area, so as to be more competitive in specific applications.
4. Embedded systems are organically integrated with specific applications, and their upgrades and replacements are carried out in sync with specific products. Therefore, once embedded system products enter the market, they have a long life cycle.
5. In order to improve execution speed and system reliability, the software in embedded systems is generally embedded in memory chips or the microcontroller itself, rather than stored on disks or other media.
6. Embedded systems do not have independent development capabilities. Even after the design is completed, users usually cannot modify the program functions. A set of development tools and environment that connect to a general computer system is required for development.
The information age and the digital age have provided embedded products with tremendous development opportunities, showcasing a bright future for the embedded market. At the same time, they have also presented new challenges to embedded manufacturers. From this, we can see several major development trends in future embedded systems:
1. Embedded development is a systematic project. Therefore, embedded system manufacturers are required not only to provide the embedded hardware and software system itself, but also to provide powerful hardware development tools and software package support so that users can launch their products at the lowest cost and in the shortest time.
Many manufacturers have already taken this into full consideration, promoting their development environments alongside their operating systems. For example, Samsung provides development boards and board support packages (BSPs) along with its Arm7 and Arm9 chips. Windows CE also offers EmbeddedVC++ as a development tool when promoting its operating system. Other typical examples of this trend include VxWorks' Tonado development environment and DeltaOS' Limda compilation environment. Of course, this is also a result of market competition.
2. The requirements for networking and informatization are increasing with the maturity of Internet technology and the improvement of bandwidth. This has made previously single-function devices such as telephones, mobile phones, refrigerators, and microwave ovens no longer have single functions and their structures are more complex.
This necessitates chip design manufacturers integrating more functions onto chips. To meet the demands of upgraded applications, designers are employing more powerful embedded processors, such as 32-bit and 64-bit chips or signal processors (DSPs), to enhance processing capabilities. Simultaneously, they are adding functional interfaces, such as USB, expanding bus types, such as CAN bus, and strengthening multimedia and graphics processing, gradually implementing the concept of a System-on-a-Chip (SoC, which integrates all necessary functions onto a single chip). On the software side, real-time multitasking programming techniques and cross-development tools are used to control functional complexity, simplify application design, ensure software quality, and shorten development cycles.
3. Network interconnection is becoming an inevitable trend. Future embedded devices, in order to adapt to the requirements of network interconnection, will inevitably require various network communication interfaces in their hardware. Traditional microcontrollers lack sufficient network support.
The new generation of embedded processors has begun to embed network interfaces. In addition to supporting the TCP/IP protocol, some also support one or more of the following communication interfaces: IEEE 1394, USB, CAN, Bluetooth, RFID, or IrDA. They also require corresponding communication networking protocol software and physical layer driver software. On the software side, the system kernel supports a network module to enable embedded devices to connect to the Internet anytime, anywhere, in various ways.
4. Simplify the system kernel and algorithms to reduce power consumption and hardware/software costs. Future embedded products will be tightly integrated hardware and software devices. To reduce power consumption and cost, designers need to simplify the system kernel as much as possible.
Retaining only the hardware and software closely related to system functionality, and achieving the most appropriate functions with minimal resources, requires designers to select the best programming model and continuously improve algorithms, optimizing compiler performance. Therefore, software engineers need extensive hardware knowledge, and there is a need to develop advanced embedded software technologies such as Java, Web, and WAP.
5. Provide a user-friendly multimedia human-machine interface. For embedded devices to be able to interact closely with users, the most important factor is providing a very user-friendly interface. Graphical interfaces and flexible control methods make embedded devices feel like a familiar old friend.
These requirements necessitate that embedded software designers invest significant effort in graphical interfaces, voice interaction, and other multimedia technologies. Handwritten text input, voice dial-up internet access, sending and receiving emails, and the display of color graphics and images all contribute to a sense of freedom for users.
In short, while other technologies involve a specific aspect of the Internet of Things (IoT), such as sensing, computing, and communication, embedded technology represents the various forms of objects within the IoT, integrating other technologies in these embedded devices.
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