Hardware Units in Embedded System

Overview of Hardware Units in Embedded System

An Embedded System has the following essential units in it.

Processor  - Brain of an Embedded System.  It is the one which has Control Unit and Execution Unit.

Control Unit:

• Controls Program flow and data path
• Includes a fetch unit  - to fetch program instructions from memory

Execution Unit:

• Includes Arithmetic and Logic Unit
• Execute instructions for a program control task  like interrupt, halt, reset, call jump
• Execute application program instructions

A processor is mostly in the form of an IC chip. It could be in the form of ASIC or SoC.  Processor core is a part of functional circuit on a chip.
Processor chip or core can be,

• General Purpose Processor (GPP)
• Application Specific System Processor (ASSP)
• Multiprocessor using GPP and Application Specific Instruction Processor (ASIP)
• GPP cores or ASIP cores integrated in to an ASIC or VLSI chip
• FPGA core integrated with processor units in a VLSI chip

General Purpose Processor:
A processor having a general purpose instruction set and readily available compilers to enable programming in a high level language is called General Purpose Processor. It can be Microprocessor, Microcontroller, Embedded Processor, and Digital Signal Processor.

Microprocessor:
It has CPU on a chip. It may include additional units like cache memory and floating point processing units for faster processing.

Microcontroller:
It has CPU, memory and other functional units on a chip. It includes peripherals like interrupt handler, IO ports, Timer, ADC, etc...

Embedded Processors:
These are special microprocessors and microcontrollers for fast, precise and intensive calculations. It is for complex real time applications. It is specifically designed for Fast context switching, lower latencies and Atomic ALU operations.

Digital Signal Processor:
A special processor designed for signal processing. It provides fast, discrete-time signal processing instructions. It is for fast execution of algorithms for signal analyzing, filtering, noise cancellations, compression and decompression.

Application Specific System Processor:
These are the specially designed application specific processor. It is mainly used for video compression and decompression. It can be interface to other processors.

Power Source:

• System own power supply
• Supply from a system to which the embedded system interface
• Proper Power Dissipation Management implementation in hardware and software

Oscillator and Clocking:

• Crystal oscillator circuit
• Timers and RTC for software

Reset:

• Reset on Power-up
• External and internal Reset
• Reset of Timeout, watchdog timer

Memory:

• Program , Code Memory – Internal  or external ROM, EPROM, Flash
• Data, Stack, Heap  Memory - Volatile Internal , External or Buffer RAM Memory
• Log, Configuration, Lookup table -  Non Volatile EEPROM or Flash
• Cache Memory

Interrupt Handler:

• Interrupt handler for peripheral IO and timer interrupts.

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Related topics:
Embedded System Architecture   |   Embedded Hardware Architecture   |   Embedded Software Architecture   |   Embedded Software Definition   |   Embedded System Acronyms   |   Embedded System Symbols

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List of topics: Embedded System

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