Microprocessors

Objectives :

  • Discuss the working of microprocessor
  • Discuss the various interfaces of microprocessor
  • List the types of microprocessors
  • Discuss the evolution of microprocessors
  • List the various microprocessor designs
  • Install the microprocessor
  • Configure the microprocessor
  • Upgrade the microprocessor
  • Troubleshoot the microprocessor

Working of the Microprocessor :

  • Accepts data
  • Processes data
  • Stores data
  • Sends output data
Working-of-the-Microprocessor

Parts of microprocessor - I :

Arithmetic and Logic Unit

Control Unit - Controls the flow of the data and information to other units of the microprocessor

Prefetch Unit - Controls the flow of the data and gives instructions to the Decode unit from the Instruction cache

Instruction and Data Cache – Stores instructions and data temporarily

Bus Unit - Connects the internal units of the microprocessor like the control unit and prefetch unit.

Decode Unit - Decodes the various instructions sent to the microprocessor

Registers - Store data required by the ALU

Speed of Microprocessor :

Depends on number of instructions it processes

Bandwidth (32/64 bit)

Clock speed (GHz)

Number of transistors built into it

Multitasking/Multiprocessing :

Multitasking means the processor time is divided into no. of tasks

Enables the processor to run multiple program simultaneously

Reduces the processor idle time

Multiprocessing means parallel processing used for simultaneously running more than one process by multiple processing units

Each processing unit runs independently and may or may not have individual cache memory

Most effective when used with application software

Interface of Microprocessor :

Steps followed by the microprocessor to interface with a device :

Checks the status of the device.

Requests the device for transferring data.

The device sends the data request to the microprocessor.

The microprocessor sends the required data to the device.

FSB/BSB :

FSB interfaces between the L2 cache on processor to the north bridge of motherboard

Also known as system bus or memory bus

Speed at which CPU communicates with RAM

BSB interfaces between L1 cache on processor with L2 cache

BSB is faster than FSB

Operating Voltage of Microprocessor :

Lowering the operating voltage decreases the power consumption

Less power consumption, system is less expensive to run and more battery life

Less voltage of the equipment generates less heat

Processors that run cooler give better performance

Operating voltage range is 1.5 to 2.9V

Packaging of microprocessor - I :

Types of microprocessor packaging :

Pin Grid Array (PGA) - Mainly used with modern high speed microprocessors due to the enhanced thermal and electrical properties of the ceramic material

Staggered Pin Grid Array (SPGA) – Pins are staggered rather than arranged in standard rows and columns. Allows to move the pins closer and decrease the size of chip

Single edge contact (SEC) and single edge processor packaging (SEPP) - SEC cartridge incorporates the back side bus and L2 cache internally. It was a cost effective method for integrating L2 cache into the processor. A less expensive of the SEC is the single edge processor (SEP) package without fancy plastic cover

Types of microprocessor - I :

Based on the number of instructions built into it, they can be classified as :

  • Complex Instruction Set Computing (CISC) – Many instructions built into it which saves processing time for performing tasks otherwise it has to be retrieved from RAM. However it affects the performance of the microprocessor because more time is taken to process the instruction and also the space available on the microprocessor for processing reduces. To overcome this problem more transistors need to be built into the microprocessor
  • Reduced Instruction Set Computing (RISC) – Have limited instructions built into it which requires few transistors to be built into the microprocessor. Saves the space in the microprocessor and cheaper as compared to CISC processor. This processor is favorable for scientific purposes where limited instructions are required

Microprocessors Timeline :

Microprocessors-Timeline

Intel Pentium Microprocessor :

Designed to work with everyday applications

  • Word processors
  • Spreadsheets
  • Multimedia applications
  • Games

Versions :

  • Pentium I
  • Pentium II
  • Pentium III
  • Pentium IV

Pentium I :

Released in 1993

First chip from the fifth generation of microprocessors

Has a 5-stage data pipeline for executing instructions to perform multiple calculations simultaneously

Pentium II :

Released in 1997

Available on a daughter card that has L2 cache

Has a 14-stage data pipeline for executing instructions

Pentium III :

Released in 1999

Has a unique Processor Serial Number (PSN) embedded in the chip

Has a 10-stage data pipeline for executing instructions

Has 70 more instructions built into it which enhances processing of graphical information

Pentium IV :

Released in 2000

Enables to work with applications that require a lot of processing such as digital photography

Pentium-IV

Has a 20-stage data pipeline for executing instructions

Also available in the following editions :

  • Hyper-Threading (HT)
  • HT Extreme

Advanced Micro Devices (AMD) :

Created in the year 1969

Developed

  • Duron
  • Athlon

Cheaper than Pentium processors

Uses Slot A to connect the AMD microprocessor to the motherboard

Dual Core :

Two cores on a single die comprise a dual core CPU

Each of the cores has their own cache, can process independently and provide better performance

To make use of dual core technology, the process must use multiple threads

Well suited for multitasking environment

Intel and AMD provide dual core processors for various segments

Install Microprocessor in ZIF socket and heat sink

  • Check voltage requirements
  • Wear an anti-static wristband
  • Place motherboard on work desk
  • Take microprocessor out from anti-static bag
  • Check that all pins on underside of microprocessor are straight
  • Locate socket where microprocessor must be installed
  • Find lever located besides the socket for microprocessor
  • Raise lever so that it is at right angle with motherboard
  • Align notch on microprocessor with alignment notch on motherboard socket
  • Gently, place microprocessor in the socket
  • Push lever back down such that it is parallel to motherboard and locked in place

Heat Sink :

A component that is used to lower the temperature of an electronic device which absorbs heat from the electronic device and distributes it to surrounding environment. Two types of heat sinks available namely :

Passive Heat Sink – The passive heat sink is a metal plate with fins attached to surface of the processor. The plane of the heat sink absorbs the heat of processor and fins streams the air to cool it.

Active Heat Sink – An active heat sink is an expansion of passive heat sink with a fan attached on top of the plane metal surface. This facilitates direct cooling of the processor.

Overclocking :

Overclocking increases the speed of the microprocessor

You can overclock the microprocessor by changing jumper settings on motherboard or by changing appropriate BIOS settings

Additional cooling devices such as CPU fan must be installed to cool down the processor

Must be done with a great care by increasing clock speed as little as possible every time

Must check documentation of the microprocessor and motherboard before overclocking

Overclocking a processor beyond its maximum capacity can permanently damage the microprocessor