14-06-2012, 05:08 PM
DIAMOND SECURITY SYSTEM IN MUSEUM WITH LOUD 60DB SIREN
INTRODUCTION:
An embedded system is a computer system designed for specific control functions within a larger system.often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal computer (PC), is designed to be flexible and to meet a wide range of end-user needs. Embedded systems control many devices in common use today.
Embedded systems contain processing cores that are typically either microcontrollers or digital signal processors (DSP). The key characteristic, however, is being dedicated to handle a particular task. They may require very powerful processors and extensive communication, for example air traffic control systems may usefully be viewed as embedded, even though they involve mainframe computers and dedicated regional and national networks between airports and radar sites (each radar probably includes one or more embedded systems of its own).
Since the embedded system is dedicated to specific tasks, design engineers can optimize it to reduce the size and cost of the product and increase the reliability and performance. Some embedded systems are mass-produced, benefiting fromeconomies of scale.
FIG
icture of the internals of an ADSL modem/router. A modern example of an embedded system. Labelled parts include a microprocessor (4), RAM (6), and flash memory(7).
Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations liketraffic lights, factory controllers, or the systems controlling nuclear power plants. Complexity varies from low, with a single microcontroller chip, to very high with multiple units, peripherals and networks mounted inside a large chassis or enclosure.
In general, "embedded system" is not a strictly definable term, as most systems have some element of extensibility or programmability. For example, handheld computers share some elements with embedded systems such as the operating systems and microprocessors that power them, but they allow different applications to be loaded and peripherals to be connected. Moreover, even systems that do not expose programmability as a primary feature generally need to support software updates. On a continuum from "general purpose" to "embedded", large application systems will have subcomponents at most points even if the system as a whole is "designed to perform one or a few dedicated functions", and is thus appropriate to call "embedded".
Characteristics:
FIG:Gumstix Overo COM, a tiny, OMAP-based embedded computer-on-module with Wifi and Bluetooth.
1. Embedded systems are designed to do some specific task, rather than be a general-purpose computer for multiple tasks. Some also have real-time performance constraints that must be met, for reasons such as safety and usability; others may have low or no performance requirements, allowing the system hardware to be simplified to reduce costs.
2. Embedded systems are not always standalone devices. Many embedded systems consist of small, computerized parts within a larger device that serves a more general purpose. For example, the Gibson Robot Guitar features an embedded system for tuning the strings, but the overall purpose of the Robot Guitar is, of course, to play music. Similarly, an embedded system in anautomobile provides a specific function as a subsystem of the car itself.
FIG:e-con Systems eSOM270 & eSOM300 Computer on Modules
3. The program instructions written for embedded systems are referred to as firmware, and are stored in read-only memory or Flash memory chips. They run with limited computer hardware resources: little memory, small or non-existent keyboard and/or screen.
Peripherals:
Embedded Systems talk with the outside world via peripherals, such as:
Serial Communication Interfaces (SCI): RS-232, RS-422, RS-485 etc.
Synchronous Serial Communication Interface: I2C, SPI, SSC and ESSI (Enhanced Synchronous Serial Interface)
Universal Serial Bus (USB)
Multi Media Cards (SD Cards, Compact Flash etc.)
Networks: Ethernet, LonWorks, etc.
Fieldbuses: CAN-Bus, LIN-Bus, PROFIBUS, etc.
Timers: PLL(s), Capture/Compare and Time Processing Units
Discrete IO: aka General Purpose Input/Output (GPIO)
Analog to Digital/Digital to Analog (ADC/DAC)
Debugging: JTAG, ISP, ICSP, BDM Port, BITP, and DP9 ports.
MICRO CONTROLLERS
Microprocessors vs. Microcontrollers:
• Microprocessors are single-chip CPUs used in microcomputers.
• Microcontrollers and microprocessors are different in three main aspects: hardware architecture, applications, and instruction set features.
• Hardware architecture: A microprocessor is a single chip CPU while a microcontroller is a single IC contains a CPU and much of remaining circuitry of a complete computer (e.g., RAM, ROM, serial interface, parallel interface, timer, interrupt handling circuit).
• Applications: Microprocessors are commonly used as a CPU in computers while microcontrollers are found in small, minimum component designs performing control oriented activities.
• Microprocessor instruction sets are processing Intensive.
• Their instructions operate on nibbles, bytes, words, or even double words.
• Addressing modes provide access to large arrays of data using pointers and offsets.
• They have instructions to set and clear individual bits and perform bit operations.
• They have instructions for input/output operations, event timing, enabling and setting priority levels for interrupts caused by external stimuli.
• Processing power of a microcontroller is much less than a microprocessor.
Difference between 8051 and 8052:
The 8052 microcontroller is the 8051's "big brother." It is a slightly more powerful microcontroller, sporting a number of additional features which the developer may make use of:
• 256 bytes of Internal RAM (compared to 128 in the standard 8051).
• A third 16-bit timer, capable of a number of new operation modes and 16-bit reloads.
• Additional SFRs to support the functionality offered by the third timer.
INTRODUCTION:
An embedded system is a computer system designed for specific control functions within a larger system.often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal computer (PC), is designed to be flexible and to meet a wide range of end-user needs. Embedded systems control many devices in common use today.
Embedded systems contain processing cores that are typically either microcontrollers or digital signal processors (DSP). The key characteristic, however, is being dedicated to handle a particular task. They may require very powerful processors and extensive communication, for example air traffic control systems may usefully be viewed as embedded, even though they involve mainframe computers and dedicated regional and national networks between airports and radar sites (each radar probably includes one or more embedded systems of its own).
Since the embedded system is dedicated to specific tasks, design engineers can optimize it to reduce the size and cost of the product and increase the reliability and performance. Some embedded systems are mass-produced, benefiting fromeconomies of scale.
FIG
icture of the internals of an ADSL modem/router. A modern example of an embedded system. Labelled parts include a microprocessor (4), RAM (6), and flash memory(7).Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations liketraffic lights, factory controllers, or the systems controlling nuclear power plants. Complexity varies from low, with a single microcontroller chip, to very high with multiple units, peripherals and networks mounted inside a large chassis or enclosure.
In general, "embedded system" is not a strictly definable term, as most systems have some element of extensibility or programmability. For example, handheld computers share some elements with embedded systems such as the operating systems and microprocessors that power them, but they allow different applications to be loaded and peripherals to be connected. Moreover, even systems that do not expose programmability as a primary feature generally need to support software updates. On a continuum from "general purpose" to "embedded", large application systems will have subcomponents at most points even if the system as a whole is "designed to perform one or a few dedicated functions", and is thus appropriate to call "embedded".
Characteristics:
FIG:Gumstix Overo COM, a tiny, OMAP-based embedded computer-on-module with Wifi and Bluetooth.
1. Embedded systems are designed to do some specific task, rather than be a general-purpose computer for multiple tasks. Some also have real-time performance constraints that must be met, for reasons such as safety and usability; others may have low or no performance requirements, allowing the system hardware to be simplified to reduce costs.
2. Embedded systems are not always standalone devices. Many embedded systems consist of small, computerized parts within a larger device that serves a more general purpose. For example, the Gibson Robot Guitar features an embedded system for tuning the strings, but the overall purpose of the Robot Guitar is, of course, to play music. Similarly, an embedded system in anautomobile provides a specific function as a subsystem of the car itself.
FIG:e-con Systems eSOM270 & eSOM300 Computer on Modules
3. The program instructions written for embedded systems are referred to as firmware, and are stored in read-only memory or Flash memory chips. They run with limited computer hardware resources: little memory, small or non-existent keyboard and/or screen.
Peripherals:
Embedded Systems talk with the outside world via peripherals, such as:
Serial Communication Interfaces (SCI): RS-232, RS-422, RS-485 etc.
Synchronous Serial Communication Interface: I2C, SPI, SSC and ESSI (Enhanced Synchronous Serial Interface)
Universal Serial Bus (USB)
Multi Media Cards (SD Cards, Compact Flash etc.)
Networks: Ethernet, LonWorks, etc.
Fieldbuses: CAN-Bus, LIN-Bus, PROFIBUS, etc.
Timers: PLL(s), Capture/Compare and Time Processing Units
Discrete IO: aka General Purpose Input/Output (GPIO)
Analog to Digital/Digital to Analog (ADC/DAC)
Debugging: JTAG, ISP, ICSP, BDM Port, BITP, and DP9 ports.
MICRO CONTROLLERS
Microprocessors vs. Microcontrollers:
• Microprocessors are single-chip CPUs used in microcomputers.
• Microcontrollers and microprocessors are different in three main aspects: hardware architecture, applications, and instruction set features.
• Hardware architecture: A microprocessor is a single chip CPU while a microcontroller is a single IC contains a CPU and much of remaining circuitry of a complete computer (e.g., RAM, ROM, serial interface, parallel interface, timer, interrupt handling circuit).
• Applications: Microprocessors are commonly used as a CPU in computers while microcontrollers are found in small, minimum component designs performing control oriented activities.
• Microprocessor instruction sets are processing Intensive.
• Their instructions operate on nibbles, bytes, words, or even double words.
• Addressing modes provide access to large arrays of data using pointers and offsets.
• They have instructions to set and clear individual bits and perform bit operations.
• They have instructions for input/output operations, event timing, enabling and setting priority levels for interrupts caused by external stimuli.
• Processing power of a microcontroller is much less than a microprocessor.
Difference between 8051 and 8052:
The 8052 microcontroller is the 8051's "big brother." It is a slightly more powerful microcontroller, sporting a number of additional features which the developer may make use of:
• 256 bytes of Internal RAM (compared to 128 in the standard 8051).
• A third 16-bit timer, capable of a number of new operation modes and 16-bit reloads.
• Additional SFRs to support the functionality offered by the third timer.