classification of embedded systems

After studying basics and characteristics of embedded systems, here is classification of embedded system.

Generally embedded systems are classified on the basis of functionality and on the basis of hardware and software complexities. Further classification is given as below

1.      Classification of embedded system on the basis of functionality

a.       Stand alone embedded systems

b.      Real time embedded systems

c.       Networked embedded systems

d.      Mobile embedded systems

2.      Classification of embedded system on the basis of hardware and software complexities

a.       Small scale embedded systems

b.      Medium scale embedded systems

c.       Large scale/Sophisticated embedded systems

Now let’s have brief look on these types

• Stand alone embedded systems:  As name indicates, stand alone embedded systems will work by itself and does not need any host to run/control it. Required input will be taken by input devices and output according to the input is produced after suitably processing on data. Some examples of standalone embedded system include MP3 player, digital calculators, digital cameras etc which works on their own and no other system is there to control their operations.
• Real time embedded systems: Real time embedded systems are the systems that work on real time and have task deadline. These systems supposed to perform their tasks within assigned time. Real time embedded systems are time deterministic and real time operating systems (RTOS) are used which are capable of optimizing memory resources and can be loaded into semiconductor memories like EPROM (Electrically programmable read only memory). Real time embedded systems are further classified as hard real time embedded system and soft real time embedded system.
• Networked embedded systems: Embedded systems that uses network to access resources are called as networked embedded systems. Network may in the form of LAN, WAN, MAN, internet, wired or wireless. One example of networked embedded system is security system in which surveillance cameras are connected to one device (DVR) and can be accessed over internet also.
• Small scale embedded systems: Small scale embedded systems generally uses 8-bit or 16-bit processors/controllers along with assembly language, C-language and Java as a programming language. As these systems are small scale, they use battery as a power source for operation.
• Medium scale embedded systems: Medium scale embedded systems generally uses 16-bit or 32-bit processors/controllers along with C-language, C++, visual C and Java as a programming language. As these systems are moderately complex in terms of hardware and software, Digital Signal Processors (DSP’s) or Reduced Instruction Set Computers (RISC) are employed.
• Large scale embedded systems: Large scale embedded systems generally uses scalable (able to change) i.e. configurable processors, Application Specific Instruction-Set Processors (ASIP), Digital Signal Processors (DSP’s) or Programmable Logic Array (PLA’s) along with re-targetable compilers. These kind of embedded systems are used for high end applications where cost is no issue or specific task cannot be compromised.

 Outcome of this topic: To understand classification of embedded systems