Embedded System has become an integral part of human lives though they are designed to function with minimal or no human interference. Aspects like low cost, compressed size, and simple design make them very popular. These systems, today, play a vital role in many devices, equipment instrumentation and home appliances and is likely to continue in the recent future. This post discusses what is Embedded System, its characteristics, types, advantages and disadvantages.
What is Embedded System
To simply say that an Embedded System is an integrated system including both hardware and software is not enough. An embedded system is a dedicated computer system, designed to work for single or few specific functions often within a larger system. Embedded Systems, therefore, are
- Built to function with little or no human intervention
- Specially designed keeping in consideration the tasks that need completion in the most efficient way
These systems are different from the general-purpose computers (desktops and laptops) – the general-purpose computer can handle a wide range of processing tasks unlike embedded systems.
Most of our gadgets like washing machines, microwave ovens, ATMs and mobile phones have embedded-system in them. Any device, including toys, using electric power has a computing system embedded in it.
Fig. 1 – Introduction to Embedded System
Characteristics of Embedded Systems
Some of the key characteristics of Embedded Systems are as mentioned below.
- All Embedded Systems are task specific. They do the same task repeatedly /continuously over their lifetime. An mp3 player will function only as an mp3 player.
- Embedded systems are created to perform the task within a certain time frame. It must therefore perform fast enough. A car’s brake system, if exceeds the time limit, may cause accidents.
- They have minimal or no user interface (UI). A fully automatic washing machine works on its own after the programme is set and stops once the task is over.
- Some embedded systems are designed to react to external stimuli and react accordingly. A thermometer, a GPS tracking device.
- Embedded systems are built to achieve certain efficiency levels. They are small sized, can work with less power and are not too expensive.
- Embedded systems cannot be changed or upgraded by the users. Hence, they must rank high on reliability and stability. They are expected to function for long durations without the user experiencing any difficulties.
- Microcontroller or microprocessors are used to design embedded systems.
- Embedded systems need connected peripherals to attach input & output devices.
- The hardware of an embedded-system is used for security and performance. The Software is used for features.
Fig. 2 – Characteristics of Embedded System
Types of Embedded System
Embedded systems can be classified based on:
- Performance and Functional requirements
- Performance of the Microcontroller
Fig. 3 – Types of Embedded System
Performance and Functional Requirement Based Embedded Systems
Embedded Systems can be classified into four types based on the performance and functional requirement.
- Real Time Embedded Systems
- Stand-Alone Embedded Systems
- Networked Embedded Systems
- Mobile Embedded Systems
Real Time Embedded Systems
A Real Time Embedded System provides output within a defined specific time. That is, real time embedded systems are designed and created to perform some specific work in pre-specified time.
Types of Real Time Embedded Systems
There are two types of Real Time Embedded System. They are:
- Soft Real Time Embedded Systems
- Hard Real Time Embedded Systems
Stand Alone Embedded Systems
Stand-Alone Embedded Systems are those that can work by themselves i.e. they are self-sufficient and do not depend on a host system. Stand-alone embedded systems are made in a way such that an input is received, processed and thereafter the desired output is produces.
Input can be received via sensors, keyword or push button.
Networked Embedded Systems
Networked Embedded Systems depend on connected network to perform its assigned tasks.
These systems consist of components like sensors, controllers etc. which are interconnected. Many of these systems are built on general purpose processors.
Mobile Embedded Systems
Mobile Embedded Systems are those that are small sized and can be used in smaller devices.
They are used in mobile phones and digital cameras because of the small size. They often have memory constraints and lacks good user interface.
Microcontroller Performance Based Embedded System
Embedded System are classified in three types based on its microcontroller performance.
- Small Scale Embedded Systems
- Medium Scale Embedded Systems
- Sophisticated Embedded Systems
Small Scale Embedded System
Small Scale Embedded System is normally designed and created using an 8-bit microcontroller. This microcontroller can be battery activated.
Medium Scale Embedded System
Medium Scale Embedded System uses a single 16-bit or 32-bit microcontroller or multiple microcontrollers linked together. These systems have a lot of hardware as well as software complexities, hence are not preferred by many.
Sophisticated Embedded System
Sophisticated Embedded System often function on multiple algorithms that results in complexities in both hardware and software. They often need a processor that is configurable and logic array that can be programmed.
Applications of Embedded System
Fig. 4 – Applications of Embedded System
Some real-life applications of Embedded Systems are as follows:
- Consumer electronics – Televisions and digital cameras; computer printers; video game consoles and home entertainment systems like PS4.
- Household appliances – Refrigerators; washing machines, microwave ovens, air conditioners
- Medical equipment – Scanners like those for MRI, CT; ECG machines; devices to monitor blood pressure and heartbeat
- Automobiles – Fuel injection systems, anti-lock braking systems, music and entertainment systems, controls for air-conditioner
- Industrial applications – Assembly lines, systems for feedback, systems for data collection
- Aerospace – Systems for navigation and guidance, GPS
- Communications – Routers, satellite phones
Though Mobile phones use embedded system, they operate in a way akin to general purpose computers; hence not included in the above list.
Advantages of Embedded System
The advantages of Embedded Systems are:
- They are convenient for mass production. This results in low price per piece.
- These systems are highly stable and reliable.
- Embedded systems are made for specific tasks.
- The embedded systems are very small in size, hence can be carried and loaded anywhere.
- These systems are fast. They also use less power.
- The embedded systems optimize the use or resources available.
- They improve the product quality.
Disadvantages of Embedded System
The disadvantages of Embedded Systems are as follows:
- Once configured, these systems cannot be changed. Hence, no improvement or upgradation on the ones designed and created can be made.
- They are hard to maintain. It is also difficult to take a back-up of embedded files.
- Troubleshooting is difficult for embedded systems. Transferring data from one system to another is also quite problematic.
- Because these systems are made for specific tasks, hardware is limited.
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