Embedded Systems and its classification.
Embedded systems
Characteristics Of embedded systems
Classification Of embedded systems based on generation
Let's Begin..
Definition : Embedded systems are computing systems with tightly coupled hardware and software integration that are designed to perform a dedicated function.
Embedded systems cover a large range of computer systems from ultra small computer based devices to large systems monitoring and controlling complex processes.
In most of the cases embedded systems are real-time systems. In many cases embedded systems are safety or mission critical systems.
Real-time systems are those systems in which the overall correctness of the system depends on both the functional correctness and timing correctness. Real-time systems also have a substantial knowledge of the system it controls and the applications running on it. These are deadline dependent.
Characteristics Of Embedded Systems
- It has limited memory and limited number of peripherals.
- They need to be highly reliable and stable.
- It should be small set of function.
- Typically designed for a specific purpose.
- Safety, security, real-time, power consumption.
Classification Of Embedded Systems
- First Generation computers
The early embedded systems were built around 8 bits microprocessors like 8085 and z80 and 4 bits microcontrollers. Simple in hardware circuits with firmware development in assembly code.
Ex: Telephone keypads, stepped motor control units etc.
- Second Generation computers
They are embedded systems built around 16 bit microprocessor and 32 bit microcontroller following the first generation embedded systems. The instruction set of the second generation is complex and powerful.
Ex: Data Acquistion systems, SCADA systems, etc..
- Third Generation computers
Embedded systems developers started making use of powerful 32 bit processor and 16 bit controller for their design. A new concept of application and domain specific processor/controllers like digital signal processors (DSP) and application specific integrated circuits(ASICs) came into the picture. The instruction set of processors become more complex and powerful.
Ex: Intel pentium, Motorola 68k.
- Fourth Generation computers
The advent of systems on chips(SOC), reconfigurable processors and multicore processors are bringing high performance tight integration and miniaturisation into the embedded device market. The SOC technique implement a total system on a chip by integrating different functionalities with a processor core on an integrated circuit.
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