Types of Embedded Systems – Embedded systems can be classified based on the functionality and the performance.
The embedded systems are classified into four segments according to their functionality and application area.
- Stand-alone embedded systems
- Real-time embedded systems
- Networked embedded systems
- Mobile embedded systems
The embedded systems classified based on the performance and architecture.
- Small Scale Embedded System
- Medium Scale Embedded Systems
- Sophisticated or Complex Embedded Systems
Table of Contents
Stand Alone Embedded Systems
The stand-alone embedded systems are less complex and simple. They independent to any system, work by their own. It takes user input and acts accordingly. The input is received by the respective I/O pins. The input may be in digital or in analog form. The MCU then process the input and make a decision and perform output like the display on LCD, driving motor or trigger an alarm.
Examples: Microwave Oven, the digital wristwatch, mp3 player, doorbell, calculator etc.
Real-Time Embedded Systems
A real-time embedded system performs the task in the defined time interval. The time interval may vary and depends on the application. The real-time embedded systems are defined in two parts:
- Soft Real-Time Embedded Systems
- Hard Real-Time Embedded Systems
Soft Real-Time Embedded Systems
In this type of embedded systems, the deadline to complete the task may vary. The action performed by the system after the given time frame is still acceptable and useful.
Example: While using a microwave oven, you put the item into the oven and press a button to start cooking. The oven responds to your input after 1-2 minutes. Even there is the delay but it cooks well. It crosses the deadline to complete the task.
Hard Real-Time Embedded Systems
In this type of embedded systems, the task must complete by a given deadline. The action performed after the given time interval may not accept. There is a certain application where the system should respond within the time frame.
For example, Traffic Light Controller. In the traffic light, the system should control the ON and OFF period of the signal in a defined way. If they perform with a delay then some accident may happen.
Networked Embedded Systems
As the name tells networked embedded systems. The embedded systems are connected with some kind of network. The system communicates with the server or with the individual node using the network. We are using such kind of networked system in our day to day life.
The communication may establish by using LAN, WAN or other protocols. This may be wired or wireless network.
Examples:
- Security node connected to the main server in a home automation system
- ATM machine
- Card Swipe Machine
- IOT Devices
Mobile Embedded Systems
The mobile embedded systems are the most preferred in any embedded systems. The cell phone, mobile phone, wireless camera, personal digital assistant are the example of it. The main advantage of this type of embedded systems is the wide range.
Small Scale Embedded System
Small-scale embedded systems are an entry-level system in which 8-bit or 16-bit processor is used. The processor has very limited resources like RAM, ROM and processing speed.
For the development of the small-scale embedded system, we need integrated development environment(IDE) for writing the code. The code is generally written in assembly language or in embedded C language. The compiler is needed if programming in embedded C. Compiler compiles the C code into the Hex code. We need assembler if we are coding in assembly language.
And at the time of writing the code into the processor. We need a hardware device called the programmer. That takes the hex code and write it to the ROM of the processor.
Examples of Small Scale Embedded Systems
- washing machine
- Oven
- Automatic Door Lock
- Motion Controlled Home Security System
- Keyboard controller
- CD Drive
- fax machine
- photocopy machine
- printer
chocolate vending machine, washing machine, cooking system, multitasking toys, keyboard controller, MMI and network access cards, CD drive or hard disk drive controller, Fax machine, photocopy or printer machine, Remote controller of TV, Telephone with memory, display and other sophisticated features,
The small-scale embedded systems are small and can be operated with a small battery.
Medium Scale Embedded Systems
This type of embedded systems consisting of 16-bit or 32-bit microprocessor. There are other options also available like Digital signal processor(DSP), or some Advanced RISC architecture machine. The medium scale embedded systems are generally faster than the small scale due to the number of bits of processor that give a better speed.
At the time of development, we need different types of software tools like assembler, compiler and debugger. An RTOS can be implemented on medium scale embedded systems.
Sophisticated or Complex Embedded Systems
This type of embedded systems is made to perform the complex functions. The systems have hardware and software complexity. In this type of systems, the speed is measure concern. So some of the software functionality is implemented into the hardware. There are different modules are implemented on the CPU like TCP/IP, encryption, decryption, multiplier unit and more. Once the functionality is implemented into hardware the gives the better speed.
This type of systems have some key components like graphical user interface, communication ports like I2C, CAN, RS232, Ethernet or USB. You can see this type of system as network router, IP camera, embedded web server.