Embedded design refers to the development of the embedded operating system, including hardware and software, and integrated research and development under the guidance of systematic design. In addition to the temporary separation of hardware EDA research and development, the focus is, under certain hardware conditions, systematic design and software development.
The complete process of embedded design includes circuit design and structure design using discrete components or integrated devices, then software programming, experimentation, and finally the development of the whole system after many rounds of modification design and production. Such embedded design development is suitable for systems with relatively single products, large production volumes, long product development cycles,s, and strict cost control.
Many industries use embedded technology, such as cell phones, PDAs, car navigation, industrial control, military, multimedia terminals, gateways, digital TV, etc. More than simple software technology or hardware technology, embedded technology is a comprehensive technology to develop and build specific programmable software systems on specific hardware environments.
The history of embedded system development
In November 1971, the arithmetic operator and controller circuits were successfully integrated together and the first microprocessor was launched, after which 8-bit and 16-bit microprocessors were launched by various manufacturers one after another. The systems composed of these microprocessors as the core are widely used in the fields of instrumentation, medical equipment, robotics, and household appliances. The wide application of microprocessors formed a broad embedded application market, computer manufacturers began to provide a large number of OEM products to users in the form of plug-ins, and then by the user according to their needs to choose a set of the suitable CPU board, memory board and a variety of I/O plug-in board, so as to constitute a special embedded computer system, and will be embedded in their own system equipment.
In the 1980s, with the improvement of the microelectronics process level, integrated circuit manufacturers began to embed computer applications that required microprocessors, I/O interfaces, A/D converters, D/A converters, serial interfaces, and RAM, ROM, and other components integrated into a VLSI, thus creating a microcontroller for I/O design, commonly known as a microcontroller. Microcontroller has become a rising star in embedded computers.
In the 1990s, in distribution control, flexible manufacturing, digital communication and information appliances, and other huge demand, embedded systems further rapid development. DSP products are oriented to real-time signal processing algorithms developed in the direction of high speed, high precision, and low power consumption.
The 21st century is an era of network prevalence, and the application of embedded systems to various networks is an important direction of its development.
The development of an embedded system has roughly gone through the following three stages
The first stage is the early stage of embedded technology. The embedded system exists in the form of a programmable controller with the simple function of a special computer or microcontroller as the core and has the functions of monitoring, servo, equipment indication, and so on. Most of such systems are used in various types of industrial control and weapons and equipment such as aircraft and missiles.
The second stage: is marked by a high-end embedded CPU and embedded operating system. The main feature of this – stage system is the emergence of computer hardware with highly reliable, low-power embedded CPUs, such as ARM, PowerPC, etc., and support for operating systems to support the development and operation of complex applications.
The third stage: is marked by chip technology and Internet technology. Microelectronics technology is developing rapidly, and SOC (System on Chip) makes embedded systems smaller and smaller, but more and more powerful. At present, most embedded systems are still isolated from the Internet, but with the development of the Internet and Internet technology and information appliances, industrial control technology, and other increasingly close combination, embedded technology is entering a period of rapid development and wide application.
Composition of embedded system
An embedded system is used in the above-mentioned industries. An embedded system is composed of hardware and software and is a device that can operate independently.
According to the architecture, the embedded system is divided into the hardware layer, middle layer, system software layer, and application software layer.
The hardware layer includes an embedded microprocessor, memory, common device interface, and I/O interface, which is the core of the embedded design system. In addition, the memory is located between the main memory and the embedded microprocessor core, which stores the most used program code and data of the microprocessor in recent times. Its main goal is to reduce the memory access bottleneck caused by the memory to the microprocessor core and make the processing speed faster.
The middle layer, also known as Hardware Abstraction Layer HAL or Board Support Package BSP, separates the upper system software from the underlying hardware so that the upper system software developer does not need to relate to the specifics of the underlying hardware and can develop according to the interface provided by the BSP layer. Designing a complete BSP requires embedded system hardware initialization and BSP functions, as well as designing hardware-related device drivers.
The system software layer consists of RTOS, file system, GUI, network system, and common component modules, where RTOS is the foundation and development platform for embedded application software.
Finally, there is the application software layer, which consists of applications developed based on the real-time system.