Embedded systems are used in many spheres of life, and their field of application, along with technical progress, is constantly expanding. Such solutions can be found in measurement equipment, including oscilloscopes, spectrum analyzers, in cars (for example, on-board computers), computer equipment (hard drives, optical drives, routers), in telecommunications solutions, in so-called smart buildings, in devices used in medical diagnostics, flight control systems, as well as, naturally, in CNC machines, robots and industrial machines and a number of control systems in automation.
Key Features Of Embedded Systems
High quality and reliability
The main feature that distinguishes embedded systems from other computer systems is, in addition to their specialized nature, the quality of the software and the hardware components used. An embedded system, because of its scope, must also be fully tested and stable – bugs here can be disastrous.
Use in small batch production
Universal embedded systems and modules can be used in the development of product prototypes and are especially successful in small-scale production, when they can significantly reduce development time and cost.
The embedded system must work in real time, that is, the system must perform certain calculations in strictly defined time intervals. First, the system must be designed in such a way that the required computation cycle fits into the allotted time interval. To do this, it is necessary to select the appropriate computational performance of the microcontroller, develop an algorithm that is efficient in terms of speed, and develop interface circuits with the lowest possible delays in signal transmission. Secondly, the embedded system must be resistant to external data. Therefore, the organization of the work of embedded systems in real time is one of the main design problems.
Size miniaturization and testing process
Many modern systems have to be built into rather miniature devices, such as a mobile phone, TV remote control, water flow sensor, etc. Very often, the geometry of the printed circuit board of a system is determined by the case of the device for which it is intended. Therefore, miniaturization of execution is one of the problems of the developer of modern embedded systems.
Most embedded systems need to serve multiple external devices in real time. Moreover, the repetition periods of the real-time computation algorithms for each of the devices are different. When developing such systems, the developer is faced with a dilemma whether to use one high-speed MC to solve the problem, or to make a multiprocessor system in which its own microprocessor or microcontroller will be used for each task.
Today it is difficult to imagine modern multimedia electronic equipment without the ability to freely choose the parameters of the music you listen to or the image you watch. This is possible thanks to the use of microprocessors that control the operation of these devices and are located inside them (hence the name: Embedded System).
Computer systems as complex digital systems were first used to automate computational processes according to a specific algorithm. However, automation may not only concern computational processes. Hence, the starting point for embedded systems development is two disciplines: automation and computer science.
The combination of methods and tools used in both automation and information technology has allowed a completely new quality to be achieved. Undoubtedly, the main source content is contained in the term: "Computer control systems". They include the analysis and assessment of computer systems in terms of the implementation of object and process control, as well as the necessary software requirements for these systems.
The development of computer systems and the increasing requirements for quality control have led to the emergence of two directions in specialized control solutions. These are programmable logic controllers (PLC) and microcontrollers. On the basis of these trends, specialized systems are being created that perform all the functions of managing objects or processes and are closely related to them.
The embedded system must meet certain requirements that are strictly defined. Therefore, it cannot be called a typical multifunctional personal computer.
Each embedded system is based on a microprocessor (or microcontroller) programmed to perform a limited number of tasks, or even just one task.
Depending on the purpose, it may contain software designed only for this device (firmware) or an operating system with specialized software. This is usually determined by the degree of reliability the embedded system has to offer.
Generally, the less complex and specialized the software is, the more reliable the system is and the faster it can respond to critical events.
The reliability of the system can be increased by dividing tasks into smaller subsystems, as well as by redundancy, which can consist in using two identical devices for one task, one of which takes over the tasks of the other in the event of a failure.
History of embedded systems
The first modern embedded real-time computing system was the Apollo Guidance Computer, developed in the 1960s by Dr. Charles Stark Draper of MIT for the Apollo program. The Apollo control computer has been designed to automatically collect data and perform critical calculations for the Apollo command module and lunar module.
In 1971, Intel released the first commercially available microprocessor, the Intel 4004, which still required support chips and external memory.
In 1978, the National Machinery Industry Association issued a standard for programmable microcontrollers, improving the design of embedded systems and by the early 1980s, the memory, input and output system components were integrated on the same chip as the processor, forming a microcontroller.
The embedded microcontroller-based system will subsequently be incorporated into all aspects of consumers' daily lives, from credit card readers and cell phones to traffic lights and thermostats.
How does an embedded system work?
Embedded systems are controlled by microcontrollers or digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic arrays (FPGAs). These processing systems are integrated with components designed to work with electrical and / or mechanical interfaces.
The programming instructions for embedded systems, called firmware, are stored in read only memory or flash memory chips that operate on a computer's limited hardware resources. Embedded systems connect to the outside world through peripherals, linking input and output devices.
How are embedded systems developed?
The design and construction of embedded systems does not fit within the existing framework of the standard disciplines with which these solutions are associated. Knowledge of both electronics and computer science is required. Undoubtedly, the most appropriate solution would be to take up the development of embedded systems after receiving training also in the field of automation and control, as well as mechatronics and robotics.
The design of an embedded system includes both the development of a special hardware level and the corresponding software. In the latter, you can separate the system area and the application area.
The system layer creates a runtime environment for an embedded application and, depending on the scope of the application, has varying degrees of complexity. For simple embedded systems with a closed, non-scalable architecture, the system layer is not strictly separate and does not contain mechanisms to support application development.
Advanced systems for medicine, aviation, telecommunications and robotics are implemented on the basis of special operating systems or libraries that contain mechanisms and functions that facilitate application development and system testing. However, the developer must extend the system level with special drivers.