“The embedded system is composed of hardware and software. The hardware is generally composed of a high-performance microprocessor and peripheral interface circuits. The software is generally composed of an operating system and an application program. The so-called middle layer (BSP layer, Board Support Package) connection.
The embedded system is composed of hardware and software. The hardware is generally composed of a high-performance microprocessor and peripheral interface circuits. The software is generally composed of an operating system and an application program. The so-called middle layer (BSP layer, Board Support Package) connection. The hardware of the embedded system includes: embedded microprocessor, memory, input and output (I/O, A/D, D/A). Embedded system software includes: operating system, application software. This paper mainly explains the components of the embedded system and the application fields of the embedded system. First, the characteristics of the embedded system are introduced, and then the components and parts of the embedded system are described. Finally, the application field is introduced.
Features of Embedded Systems
(1) Compared with hardware integration, it integrates computer technology, microelectronic technology and industry technology;
(2) Operating system support is required, the code is small, and the execution speed is fast;
(3) Dedicated pumping, fixed use and cost-sensitive;
(4) High reliability requirements;
(5) Diversity, wide application and wide variety.Components of an embedded system
From the organizational level, embedded systems are generally composed of hardware layer, middle layer, software layer and function layer.
(1) Functional layer
The functional layer is composed of application programs developed based on RTOS to complete the control function of the controlled object. The functional layer is oriented to the controlled objects and users.
(2) Intermediate layer
Between the hardware layer and the software layer is the middle layer, also known as the Hardware Abstract Layer (HAL) or the Board Support Package (BSP). The underlying driver of the system has nothing to do with the hardware, and the upper-level software developers do not need to care about the specific conditions of the underlying hardware, and can develop according to the interface provided by the BSP layer. This layer generally includes initialization of related underlying hardware, data input/output operations and configuration functions of hardware devices. In fact, BSP is a software layer between the operating system and the underlying hardware, including most of the software modules in the system that are closely related to the hardware. Designing a complete BSP needs to complete two parts of work: the BSP function of the hardware initialization of the embedded industrial system, and the design of the hardware-related device driver.
(3) Software layer
The system software layer is composed of real-time multitasking operating system (Real-TIme OperaTIon System, RTOS), file system, Graphic User Interface (Graphic User Interface, GUI), network system and general component modules. RTOS is the foundation and development platform of embedded application software.
(4) Hardware layer
The hardware layer includes embedded microprocessor, memory (SDRAM, ROM, Flash, etc.), general device interface and I/O interface (A/D, D/A, I/O, etc.). Adding a power supply circuit, a clock circuit and a memory circuit on the basis of an embedded processor constitutes an embedded core control module. The operating system and application programs can be solidified in ROM.
What are the main components of an embedded system?
1. The processor core
The heart of an embedded system is the processor core. Processor cores range from a simple and inexpensive 8-bit microcontroller, to more complex 32- or 64-bit microprocessors, or even multiple processors. Embedded designers must choose the lowest cost device for their application that meets all functional and non-functional timeframes and requirements.
2. Analog I/O
D/A and A/D converters are used to collect data and feedback from the environment. The embedded designer must understand the type of data that needs to be collected from the environment, the accuracy requirements of the data, and the rate of input/output data in order to select the appropriate converter for the application. The response characteristics of embedded systems are determined by the external environment. Embedded systems must be fast enough to keep up with environmental changes so that simulated information such as light, sound pressure or acceleration is sensed and input into the embedded system.
3. Sensors and actuators
Sensors typically perceive analog information from the environment. The actuator controls the environment in some way.
4. User interface
These interfaces can be as simple as LED screens or as complex as the screens of well-crafted cell phones and digital cameras.
5. Application specific entry
Hardware acceleration, similar to ASIC or FPGA, is used to accelerate specific functional modules that have high performance requirements in applications. Embedded designers must use accelerators for maximum application performance to properly organize or partition programs.
Software is an important part in embedded system development. Over the past few years, the amount of embedded software has grown faster than Moore’s Law, doubling almost every ten months. Embedded software is often optimized in certain aspects of performance, memory and power consumption. More and more embedded software is written in high-level languages such as C/C++. And more performance-critical code segments are still written in assembly language.
Memory is an important part of embedded systems, and embedded programs can run without RAM or ROM. There are many volatile and nonvolatile memories used in embedded systems, more on this later in the book.
8. Simulation and Diagnostics
Embedded systems are hard to see or reach. When debugging, the interface needs to be connected to the embedded system. Diagnostic ports, such as the JTAG Joint Test Action Group, are often used to debug embedded systems. On-chip emulation can be used to provide application visibility behavior. These emulation modules provide a visual representation of runtime behavior and performance, effectively replacing the functionality of an external logic analyzer with on-board self-diagnostic capabilities.
Application areas of embedded systems
1. Industrial control
Industrial automation equipment based on embedded chips will develop by leaps and bounds. At present, there are a large number of 8, 16, and 32-bit embedded microcontrollers in the application. Networking is the main way to improve production efficiency and product quality and reduce human resources, such as Industrial process control, digital machine tools, power systems, power grid security, power grid equipment monitoring, petrochemical systems. As far as traditional industrial control products are concerned, 8-bit microcontrollers are often used in low-end models. However, with the development of technology, 32-bit and 64-bit processors have gradually become the core of industrial control equipment, and will surely gain considerable development in the next few years.
2. Traffic management
Embedded system technology has been widely used in vehicle navigation, traffic control, information monitoring and automotive services. Mobile positioning terminals with embedded GPS modules and GSM modules have been successfully used in various transportation industries. At present, GPS devices have entered the homes of ordinary people from cutting-edge products. You can find your location anytime and anywhere with only a few thousand yuan.
3. Information appliances
This will be called the largest application field of embedded systems. The networking and intelligence of refrigerators and air conditioners will lead people’s lives into a new space. Even if you are not at home, it can be controlled remotely by phone line, network. Among these devices, embedded systems will be of great use.
4. Home intelligent management
Remote automatic meter reading of water, electricity and gas meters, safety fire prevention and anti-theft system, the special control chip embedded in it will replace the traditional manual inspection and achieve higher, more accurate and safer performance. At present, the advantages of embedded systems have been reflected in the service field, such as remote orderers.
5. POS network
Public transportation contactless smart card (Contactless Smartcard, CSC) issuance system, public telephone card issuance system, vending machines, and various smart ATM terminals will be fully integrated into people’s lives.
6. Environmental Engineering
Real-time monitoring of hydrological data, monitoring of flood control system and water and soil quality, dam safety, earthquake monitoring network, real-time meteorological information network, water source and air pollution monitoring. In many areas with harsh environments and complex ground conditions, the embedded system will realize unmanned monitoring.