Introduction to Embedded system with its definition and applications

Introduction to Embedded system with its definition and applications

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  Definition • Embedded system(ES) is a combination of computer hardware and software designed for a specific function. OR • Embedded System is a system composed of hardware, application software and real time operating system. It can be small independent system or large combinational system. • An Embedded System is a system that has software embedded into computer- hardware, which makes a system dedicated for a variety of application or specific part of an application or product or part of a larger system. • It is a microcontroller-based control system used to perform a specific task of operation. • Embedded systems may also function within a larger system. • The systems can be programmable or have a fixed functionality.
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  Components of ES •An embedded system is a combination of three major components: • Hardware • RTOS • Application Software
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  Components of ES •Hardware: Hardware is physically used component that is physically connected with an embedded system. It comprises of microcontroller based integrated circuit, power supply, LCD display etc. • Application software: Application software allows the user to perform varieties of application to be run on an embedded system by changing the code installed in an embedded system. • Real Time Operating system (RTOS): RTOS supervises the way an embedded system work. It act as an interface between hardware and application software which supervises the application software and provide mechanism to let the processor run on the basis of scheduling for controlling the effect of latencies.
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  Characteristics of ES •An embedded system is software embedded into computer hardware that makes a system dedicated to be used for variety of application. • Embedded system generally used for do specific task that provide real-time output on the basis of various characteristics of an embedded system. • Embedded system may contain a smaller part within a larger device that used for serving the more specific application to perform variety of task using hardware-software intermixing configuration. • It provides high reliability and real-time computation ability.
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  Advantages & Disadvantages •Advantages • Same hardware can be used in variety of application. • Lesser power requirement • Lower operational cost of system • Provide high performance and efficiency Disadvantages • Developing a system required more time. Due to functional complexity. • Skilled engineers required because one mistake may result in destroying of complete project.
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  Structure of ES
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  • Sensor: Sensorused for sensing the change in environment condition and it generate the electric signal on the basis of change in environment condition. Therefore it is also called as transducers for providing electric input signal on the basis of change in environment condition. • A-D Converter: An analog-to-digital converter is a device that converts analog electric input signal into its equivalent digital signal for further processing in an embedded system. • Processor & ASICs: Processor used for processing the signal and data to execute desired set of instructions with high-speed of operation. • Application specific integrated circuit (ASIC) is an integrated circuit designed to perform task specific operation inside an embedded system. • D-A Converter: A digital-to-analog converter is a device that converts digital electric input signal into its equivalent analog signal for further processing in an embedded system. • Actuators: Actuators is a comparator used for comparing the analog input signal level to desired output signal level for providing the error free output from the system.
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  Embedded System processors •Processors are the major part in embedded systems that take response from sensors in digital form and processing of this response to produce output in real-time processing environment is performed using processors. • For an embedded system developer it is essential to have the knowledge of both microprocessors and microcontrollers. Processors inside a system: Processors inside a system have two essential units: • Control unit: This unit in processors performed the program flow control operation inside an embedded system. The control unit also acts as a fetching unit for fetching the set of instructions stored inside a memory. • Execution unit: This unit is used for execution the various tasks inside a processors. It mainly comprises of arithmetic and logical unit (ALU) and it also include a circuit that executes the instruction sets used to perform program control operation inside processors.
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  Types of processors: •Processors inside an embedded system are of the following categories: • Application Specific System Processor(ASSP): ASSP is application dependent system processor used for processing signal of embedded system. Therefore for different application performing task a unique set of system processors is required. • Application Specific Instruction Processor(ASIP): ASIP is application dependent instruction processors. It is used for processing the various instruction set inside a combinational circuit of an embedded system. • General Purpose Processor (GPP): GPP is used for processing signal from input to output by controlling the operation of system bus, address bus and data bus inside an embedded system.
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  Compilers and Assemblers Compiler: •Compiler is used for converting the source code from a high-level programming language to a low-level programming language. It converts the code written in high level programming language into assembly or machine code. The main reason for conversion is to develop an executable program. • The operations performed by compiler are: • Code generation • Code optimization • Parsing • Syntax direct translation • Pre-processing
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  Cross-Compiler: • If aprogram compiled is run on a computer having different operating system and hardware configuration than the computer system on which a compiler compiled the program, that compiler is known as cross-compiler. Decompiler: • A tool used for translating a program from a low-level language to high-level language is called a decompiler. It is used for conversion of assembly or machine code to high-level programming language. Assembler: • Assembler is embedded system tool used for translating a computer instruction written in assembly language into a pattern of bits which is used by the computer processor for performing its basic operations. Assembler creates an object code by translating assembly language instruction into set of mnemonics for representing each low-level machine operation.
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  Peripheral Devices inEmbedded Systems • Communication of an embedded system with an outside environment is done by using different peripheral devices as a combination with microcontroller. The different peripheral devices in embedded system are:- o Universal Serial Bus (USB) o Networks like Ethernet, Local Area Network(LAN) etc o Multi Media Cards (SD Cards, Flash memory, etc) o Serial Communication Interface (SCI) like RS-232, RS-485, RS-422, etc o Synchronous Serial Communication Interface like SPI, SSC and ESSI o Digital to Analog/ Analog to Digital (DAC/ADC) o General Purpose Input/Output (GPIO) o Debugging like In System Programming (ISP), In Circuit Serial Programming (ICSP), BDM Port, etc
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  Criteria for ChoosingMicrocontroller Choosing a microcontroller is essential process in designing of embedded system. While selecting a microcontroller, make sure that it meets the system need and it must be cost effective. We need to decide whether an 8-bit, 16-bit or 32-bit microcontroller is best suitable for the computing needs of a task. Following points need to be kept in mind while selecting a microcontroller:- · Speed: The operational speed of the microcontroller or the highest speed microcontroller can support. · Packaging: Packaging is important for improving the assembling, space and prototyping of an end-product. · RAM and ROM: On the basis of operation of embedded system and memory need for storage data and programs the type of microcontroller required for designing system is decided. · Count of I/O pins: The number of input and output devices connected with the system plays an essential role in choosing the type of microcontroller. · Cost per unit: It is important in terms of final cost of the product in which the microcontroller is to be used. · Power consumption: Power consumption plays an important role for maintaining the efficiency of an embedded system