As one of the greatest inventions of the 20th century, the computer has recently entered the post-PC era. The arrival of the post-PC era also marks the birth of embedded products, such as mobile phones, PDAs, and CNC machine tools.
China boasts the world's largest consumer electronics market, ranking first globally in ownership of mobile phones, color TVs, VCD players, and home appliances. With rising economic levels and changing consumption patterns, consumers have increasingly higher demands for consumer electronics, such as flexibility, controllability, durability, and cost-effectiveness. These can all be achieved through rational and effective embedded system design and optimization. Furthermore, modern medical, measurement and control instruments, and electromechanical products demand high system reliability and real-time performance, requiring dedicated embedded systems. These needs have significantly stimulated the development and industrialization of embedded systems. The development of embedded systems will further improve the framework of the information industry, becoming an accelerator for its growth. As the complexity of embedded systems increases, hardware-software collaboration becomes crucial.
Definition of embedded system
From a product application perspective, an embedded system is a device that controls, monitors, or assists in the operation of equipment, machines, and workshops. However, people from various disciplines think about and define embedded systems from their own perspectives, resulting in a wide variety of definitions.
According to the current industry and academic consensus, embedded systems are application-centric, computer technology-based, customizable hardware and software systems designed to meet the stringent requirements of application systems in terms of functionality, reliability, cost, size, and power consumption.
Embedded hardware system
The hardware platform for most embedded systems. It consists of two parts:
1. A protocol processing module centered around a general-purpose processor, used for processing network control protocols;
2. A signal processing module centered on a digital signal processor (DSP) is used for modulation, demodulation, and digital-to-analog signal conversion.
Hardware System Architecture
The core component of an embedded system is the various types of embedded processors. Currently, according to incomplete statistics, there are over 1,000 different types of embedded processors worldwide, with more than 30 popular architecture series. Due to the extreme variability in embedded system design, the choices are diverse.
The power consumption, size, cost, reliability, speed, processing power, and electromagnetic compatibility of embedded processors are all constrained by application requirements. Key factors to consider when selecting a processor include researching available CPU suppliers, processor processing speed, technical specifications, low power consumption, software support tools, whether the processor has built-in debugging tools, and whether the processor supplier provides an evaluation board.
Embedded software system
Despite the vast market demand and promising future for embedded systems, their development has been a tortuous and painful process over the years. With the advent of microprocessors, inexpensive, compact CPUs and peripheral connections provided a stable and reliable hardware architecture. Therefore, the bottleneck limiting the development of embedded systems has become primarily in the software aspect.
Based on the operating platform, embedded software can be divided into:
1. Software running on the development platform: design, development, and testing tools, etc.
2. Software running on the embedded system: embedded operating system, application programs, drivers, and some development tools
There are many operating systems that can be used for embedded system software development, but choosing a suitable operating system depends on factors such as the development tools provided by the operating system, the difficulty of porting the operating system to hardware interfaces, the memory requirements of the operating system, whether the developers are familiar with the operating system and its APIs, whether the operating system provides hardware drivers, whether the operating system is customizable, and the real-time performance of the operating system.
Embedded application software is the key to realizing the functions of embedded systems. In order to improve execution speed and system reliability, embedded software is generally embedded in memory chips or the microcontroller itself, rather than stored on disks or other media. The software code is required to be of high quality, high reliability and high real-time performance.
Features and Applications of Embedded Systems
Both the hardware and software of embedded systems must be tailored to the specific needs of the user group. Compared with general-purpose processors, the biggest difference of embedded processors is that they do most of the work in systems designed for specific user groups. They are usually characterized by low power consumption, small size, and high integration. They can integrate many tasks inside the chip, which is conducive to miniaturization of embedded system design and greatly enhances mobility.
The power consumption, size, cost, reliability, speed, processing power, and electromagnetic compatibility of embedded processors are all constrained by application requirements.
Embedded microprocessors have four characteristics :
1. It has strong support for real-time multitasking.
Embedded systems can perform multiple tasks and have short interrupt response times, thereby minimizing the execution time of internal code and real-time kernel.
2. It has a powerful storage area protection function.
Since the software structure of embedded systems is modular, robust storage protection is required to prevent erroneous cross-interactions between software modules, which also facilitates software diagnostics.
3. Scalable processor architecture
Scalable processor architectures enable the rapid development of embedded microprocessors that meet the highest performance requirements of applications.
4. Very low power consumption
In portable wireless and mobile computing and communication devices, battery-powered embedded systems consume power in the mW or even μW range.
