Processors in Embedded Systems

Processors in Embedded Systems

A Processor in an Embedded Systems contains two essential parts

* Control Unit - Which fetches the instruction from the system memory

* Execution unit

Arithmetic and Logic Unit is also the part of Execution Unit

It performs Data Transfer and data conversion operations


Types of processors


General Purpose Processors (GPP)

  • Microprocessor

  • Microcontroller

  • Digital Signal Processors (DSPs)

  • Media Processors

    • useful for sound and image processing applications

Application Specific System Processors

The processors which are relevant to a particular application like

  • Digital TV

  • HDTV decoders

  • Set Top Boxes

  • DVD Player



Important considerations while selecting a processor

  • Instruction Set

  • Maximum bits in an operand like (8 or 16 or 32 bit)

  • Clock frequency in MHz and processing speed in MIPS (Millions of Instructions per second)

  • ability to solve the complex algorithms used in meeting the deadline for their processing



Microprocessors

It is a VLSI Chip which has a Central Processing Unit (CPU), which may have some optional components like Cache memory, Floating Point Unit (FPU),etc.



Microcontrollers

Microcontroller contains functional circuits and application specific circuits



Functional Circuits are

  • Microprocessor

  • Memory (RAM, ROM, Flash)

  • Timer (Also Watch Dog Timer)

  • Interrupt Controller

  • I/O Ports (Parallel Ports )

  • UART for Serial Communication.

Application Specific Circuits

  • LAN Controllers

  • DMA Controller (Direct Memory Access)

  • Printer Controller

  • Analog to Digital Converter (ADC)

  • Digital to Analog Converter (DAC)

  • Modem

but now a days, lot of embedded systems comes with ADC, DAC,Modem and DMA Controllers.



Digital Signal Processors


  • They are useful in developing applications like Video, audio signal processing,
  • Analog signals like ECG, EEG, Seismic Signals, etc are all processed using Digital Signal Processors.
  • Most of the DSPs are inbuilt with MAC Units (Multiply and Accumulate Units)
  • Texas instruments TM series are some of the example of DSPs

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