What is embedded system? Types and basic building blocks

Are you searching for Embedded Systems???……. Which is, actually, a practical and technical guide to understanding the mechanism that builds up an embedded system’s It is a hybrid of software and hardware. This system is simply the brain of the most of the electrical energy based systems to process, access, control and store the data. As microprocessors now become cheaper and smaller and most of the products such as digital watches, automobile engines, VCRs, elevators, microwave Owens, washing machines, LEDs, thermostats, scientific and medical instruments and automobiles industrial control equipment are driven by microprocessors. People apply this term Embedded System Architecture as like any computer system is working in these devices. Actually in this technique, computing systems embedded in most of the electronic devices that are just about any computing system other than a desktop computer.

What about its significance? Then answer is that it’s some aspects as low cost, compressed size, and simple design make this system very popular and trespass into human lives and has become essential as well. This system is designed as to run on its own without human interference. It may be required to respond to events in real time.

HISTORY of embedded system

If we look at times past, it’ll be clear that from 1930 to 40s, computers were mostly dedicated to the single-purpose task. In the earliest time of the computer, we see some distinguished embedded system which is Apollo Guidance Computer developed by Charles Stark Draper at the MIT Instrumentation Laboratory.In the 60s, Embedded System had come down in cost and taken rise in processing power and in functionality as well. The first microprocessor Intel 4004 was just designed for calculators and some others small projects but still, they required much external support in the form of memory and chips




In the mid of 80s, a new form of this technique was seemed this modern form of microcontroller allowed more spread use and that was by the end of the decade become the norm rather than the exception for many electronic devices.

KEY COMPONENTS of embedded system

PROCESSORS:

  • It is a central processing unit and acknowledged as a heart of the Embedded System.
  • It controls the actions of all the other circuits.
  • It is the hardware that runs the software and brings life to Embedded System.

MEMORY:

  • It is used as a storage device for the software that the processor executes.
  • It provides storage space for data such as intermediate results, program variable, and any other information that is generated throughout the procedure.

LANGUAGES used in embedded system

Assembly language was always proved pioneer for the Programming Embedded Systems. Nowadays, there are many languages used to develop this technique e.g. C, C++, Forth, Java with its enhancement J2ME and Ada. The majority of software developed for Embedded Systems is in C language. According to a recent survey, it is indicated that approximately 45% of the software is still developed in C language. C language can claim to have mature compilers C++. Now for error-free execution and in order to avail the more benefits of C++, professionals are doing tries to identify a subset of C++ that will be used in Embedded Systems and this is called Embedded C++.

BUILDING BLOCKS of embedded system

Let us discuss in detail the building blocks of hardware of an Embedded System.

  • Input Devices
  • Output Devices
  • Central Processing Unit
  • Communication Interfaces
  • Memory (ROM and RAM)
  • Application Specific Circuitbasic building blocks of embedded system
  • Embedded system, particularly the memory, has limited resources. It does not have secondary storage devices such as the floppy disk or CDROM.
  • These systems have to do effort against some deadlines. A specific work has to be done within a specific time. This is called Real Time System. Missing a deadline may become the cause of catastrophe- damage of property or loss of life.
  • It’s a specification of this system that it must be highly reliable that you cannot allow resetting your Embedded System.
  • Some Embedded Systems have to work in extreme environmental conditions such as in very high temperature and humidity.
  • In Embedded Systems-wide variety of operating systems and processors unlike desktop computers, where hardware platform is controlled by Intel and the operating system is controlled by Microsoft. So, making choice of the right platform is a complex task in Embedded System.

CLASSIFICATION OF EMBEDDED SYSTEM (based on performance requirements and functionality)

  • Real-Time Embedded Systems
  • Stand-alone Embedded Systems
  • Networked Information Appliances
  • Mobile Devices

That specific time period in which some specific task has to be completed are called Real-Time system. Suppose at any severe condition, a system that has to open a value within 30 milliseconds but if the value does not open within this specific time, a catastrophe may arise. Such systems with this type of strict deadlines are called Hard Real-Time Systems. An example of this system is missile embedded with a tracking system.

And in some systems, deadlines are enforced but not sticking to them so catastrophe may not be lead. Suppose you give to a DVD player a command from a remote control and there is a delay in executing that command but this delay won’t lead any serious condition. This type of systems is called Soft Real-Time system.

As the name expresses, Stand-alone system works in stand-alone mode. This system takes inputs, processes them and generates the required output. The input can be commanded from a human being e.g. pressing a button or in the form of electrical signals from transducers. The output can be in the form of electrical signals to drive another system, an LCD or LED display is used for displaying information to the user.

 That embedded system which is provided by network interfaces and accessed by networks – Local Area Network or the Internet are called Network Information Appliance. Such type of Embedded system is connected to a network. NIA systems run the protocol TCP/IP stack and then get connected to PPP or Ethernet to a network and do communication with other nodes in the network.

Such as a webcam is connected to the Internet. The webcam sends pictures in real-time to any system connected to the internet.  In such case, webcam runs the HTTP server software with TCP/IP. The door lock of a house is also an example of Embedded system with TCP/IP and HTTP. It sends an alert to your desktop and it enables you to open the door lock through the mouse click. Weather monitoring system connected to the internet running in it TCP/IP protocol suite and HTTP web server software.

Mobile Devices like Personal Digital Assistants (PDAs), mobile phones, smartphones belong to a special category of embedded systems.

CASE STUDY of embedded system

To understand the design of an Embedded System, at first, we consider the idea of acquisition system as in given below diagram. Let us consider a case of temperature measurement. and data acquisition system., First of all, we select a temperature sensor like thermometer or AD590 or LM35 or LM75 etc. After that, the analogdata acquisition example of embedded system data is converted into the digital data and signal conditioning is also properly done at the same time. Now, this digital input is supplied to the microcontroller through its ports. At next step, the data must be controlled and processed by creating a source file in a suitable program (C or Assembly) and C compilers can be used. Next, program will be debugged and found error free then it’ll be dumped into the microcontroller flash memory using ISP. Finally, microcontroller chip will act as an embedded chip.

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