Microprocessor Assingment

8/6/2019 Microprocessor Assingment

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MICROPROCESSOR

4th & 5th Assignment

Submitted By:-

Sanjeev Agarwal

CS-2,6th sem

0112CS081091



Shared Bus Operation

Shared Bus Operation



Disk memory system

A floppy disk is a data storage medium that is composed of a disk of thin, flexible ("floppy") magnetic storage medium sealed in a square or

rectangular plastic carrier lined with fabric that removes dust particles.

Floppy disks are read and written by a floppy disk drive or FDD.[1]

Invented by the American information technology company IBM, floppy

disks in 8-inch (200 mm), 5¼-inch (130 mm) and 3½-inch (90 mm)

forms enjoyed three decades as a popular and ubiquitous form of data

storage and exchange, from the mid-1970s well into the 2000s.[2]

While

floppy disk drives still have some limited uses, especially with legacyindustrial computer equipment, they have now been superseded by USB

flash drives, external hard disk drives, optical discs, memory cards and

computer networks

A hard disk drive[2] (HDD) is a non-volatile, random access device for

digital data. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written

to the platter by read/write heads that float on a film of air above the

platters.



Introduced by IBM in 1956, hard disk drives have fallen in cost and

physical size over the years while dramatically increasing in capacity.Hard disk drives have been the dominant device for secondary storage of

data in general purpose computers since the early 1960s.[3]

They have

maintained this position because advances in their areal recordingdensity have kept pace with the requirements for secondary storage.

[3]

Today's HDDs operate on high-speed serial interfaces; i.e., serial ATA

(SATA) or serial attached SCSI (SAS).

EISA BusExtended ISA (EISA) has a 32-bit data bus but still operates at

8MHz.

It is rarely used -- mainly as a disk controller or video graphicsadapter.

New pins for EISA bus are interspersed with the older pins in

the 16-bit ISA connector to

preserve compatibility with the old standard.

Most of the new EISA connections are used for the 32-bit data

and 32-bit latch address bus

VESA Local BusVESA (VL bus) is a 33MHz extension of the ISA bus used of

high-speed data transfer

applications.

It contains 32-bit address and data bus and is mainly used for

video and disk interfaces.



R equires a third connector (VESA connector) to be added b8- Bit

ISA Bus Output Interface4, 8-bit latches interfaced using an ISA interface for 32 bit

parallel data.74LS244 buffers used to ensure only one lower power TTL load

on the bus.

Loading is important as many cards can be connected on the

bus.

The DIP switch can be used to change the address thus avoiding

address conflicts with

other cards in the system.

See text for examples of output interface using a PLD and alsoan ISA bus input interface

for A-to-D converters.

16-bit ISA bus has an additional connector attached behind the

8-bit connector.

Although 8 additional data bits, D8-D15, are available, the features

most often used are the

additional interrupt request and DMA request signals.ehind thestandard 16-bit ISAit latched address bus

parallel printer interface busA parallel port is a type of interface found on computers (personal and otherwise)

for connecting various peripherals. In computing, a parallel port is a parallel

communication physical interface. It is also known as a printer port or Centronics

port. The IEEE 1284 standard defines the bi-directional version of the port, which

allows the transmission and reception of data bits at the same time

Before the advent of USB, the parallel interface was adapted to access a

number of peripheral devices other than printers. Probably one of the



earliest devices to use parallel were dongles used as a hardware key

form of software copy protection. Zip drives and scanners were earlyimplementations followed by external modems, sound cards, webcams,

gamepads, joysticks and external hard disk drives and CD-ROM drives.

Adapters were available to run SCSI devices via parallel. Other devicessuch as EPROM programmers and hardware controllers could be

connected parallel.

Current use

For consumers, the USB interface²and in some cases Ethernet ²has

effectively replaced the parallel printer port. Many manufacturers of personal computers and laptops consider parallel to be a legacy port and

no longer include the parallel interface. The guidelines for Microsoft's

Windows Logo Program "strongly discourages" systems builders from

including parallel ports.[5]

USB-to-parallel adapters are available that can

make parallel-only printers work with USB-only systems.

PCI is the most common bus found in computers today due to

plug-and-play characteristicsand ability to function with 64-bit data bus.

A PCI interface contains a series of registers, located in a small

memory device, that contain

information about the board.

The information in this registers allow the computer to

automatically configure the PCI

card (Plug-and-Play PnP feature).The microprocessor connects to the PCI bus through an

integrated circuit called a PCI

Bridge thus making the PCI bus independent of processor type

and architecture.

PCI functions with either a 32-bit or 64-bit address and data bus.



The address and data buses are multiplexed to reduce the size of

the edge connector.

32-bit and 64-bit cards.

Newest versions run at 66 MHz (twice the older 33 MHzversion).

Universal Serial Bus (USB) is a specification[1]

to establishcommunication between devices and a host controller (usually a

personal computer), developed and invented by Ajay Bhatt, while

working for Intel.[2][3]

USB has effectively replaced a variety of interfaces such as serial and parallel ports.

USB can connect computer peripherals such as mice, keyboards, digital

cameras, printers, personal media players, flash drives, Network Adapters, and external hard drives. For many of those devices, USB has

become the standard connection method.

USB was designed for personal computers, but it has becomecommonplace on other devices such as smartphones, PDAs and video

game consoles, and as a power cord. As of 2008, there are about 2 billion USB devices sold per year, and approximately 6 billion total sold

to date.[4]

Unlike the older connection standards RS-232 or Parallel port, USB connectors

also supply electric power, so many devices connected by USB do not need a

power source of their own.

The Accelerated Graphics Port (often shortened to AGP) is a high-

speed point-to-point channel for attaching a video card to a computer's



motherboard, primarily to assist in the acceleration of 3D computer

graphics. Since 2004, AGP has been progressively phased out in favor of

PCI Express. As of mid-2009, PCIe cards dominate the market, but new

AGP cards and motherboards are still available for purchase, thoughThe primary advantage of AGP over PCI is that it provides a dedicated

pathway between the slot and the processor rather than sharing the

PCI bus. In addition to a lack of contention for the bus, the point-to-

point connection allows for higher clock speeds. AGP also uses

sideband addressing, meaning that the address and data buses are

separated so the entire packet does not need to be read to get

addressing information. This is done by adding eight extra 8-bit buses which allow the graphics controller to issue new AGP requests and

commands at the same time with other AGP data flowing via the main

32 address/data (AD) lines. This results in improved overall AGP data

throughputOEM driver support is minimal.[1]

Random-access memory (RAM) is a form of computer data storage. Today, it

takes the form of integrated circuits that allow stored data to be accessed in any

order in a constant time, regardless of its physical location and whether it is

related to the previous piece of data.[1]

RAM is often associated with volatile types

of memory (such as DRAM memory modules), where its stored information is lost

if the power is removed. Many other types of non-volatile memory are RAM as

well, including most types of ROM and a type of flash memory called NOR-Flash.

The first RAM modules to come into the market were created in 1951 and were

sold until the late 1960s and early 1970s. However, other memory devices

(magnetic tapes, disks) can access the storage data in a predetermined order,

because mechanical designs only allow this.



Static random-access memory (SRAM) is a type of semiconductor memory where

the word static indicates that, unlike dynamic RAM (DRAM), it does not need to

be periodically refreshed, as SRAM uses bistable latching circuitry to store each

bit. SRAM exhibits data remanence,[1]

but is still volatile in the conventional sense

that data is eventually lost when the memory is not powered

Dynamic random-access memory (DRAM) is a type of random-access

memory that stores each bit of data in a separate capacitor within anintegrated circuit. The capacitor can be either charged or discharged;

these two states are taken to represent the two values of a bit,

conventionally called 0 and 1. Since capacitors leak charge, the

information eventually fades unless the capacitor charge is refreshed

periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SR AM and other static memory.

The main memory (the "R AM") in personal computers is Dynamic

R AM (DR AM), as is the "R AM" of home game consoles (PlayStation,

Xbox 360 and Wii), laptop, notebook and workstation computers.

The advantage of DR AM is its structural simplicity: only one transistor

and a capacitor are required per bit, compared to six transistors inSR AM. This allows DR AM to reach very high densities. Unlike flash

memory, DR AM is volatile memory (cf. non-volatile memory), since itloses its data quickly when power is removed. The transistors andcapacitors used are extremely small; hundreds of billions can fit on a

single memory chip

Read-only memory (ROM) is a class of storage medium used in

computers and other electronic devices. Data stored in ROM cannot be

modified, or can be modified only slowly or with difficulty, so it is

mainly used to distribute firmware (software that is very closely tied to

specific hardware, and unlikely to need frequent updates).In its strictest sense, ROM refers only to mask ROM (the oldest type of

solid state ROM), which is fabricated with the desired data permanently

stored in it, and thus can never be modified. Despite the simplicity of

mask ROM, economies of scale and field-programmability often make



reprogrammable technologies more flexible and inexpensive, so mask

ROM is rarely used in new products as of 2007.

Other types of non-volatile memory such as erasable programmable read

only memory (EPROM) and electrically erasable programmable read-only memory (EEPROM or Flash ROM) are sometimes referred to, in

an abbreviated way, as "read-only memory" (ROM), but this is actually

a misnomer because these types of memory can be erased and reprogrammed multiple times

[1]. When used in this less precise way,

"ROM" indicates a non-volatile memory which serves functions

typically provided by mask ROM, such as storage of program code and

nonvolatile data

EEPROM (also written E2PROM and pronounced "e-e-prom,"

"double-e prom" or simply "e-squared") stands for ElectricallyErasable

Programmable R ead-Only Memory and is a type of non-volatile

memory used in computers and other electronic devices to store small

amounts of data that must be saved when power is removed, e.g.,calibration tables or device configuration.

When larger amounts of static data are to be stored (such as in USBflash drives) a specific type of EEPROM such as flash memory is more

economical than traditional EEPROM devices. EEPROMs are realized

as arrays of floating-gate transistors.

EEPROM is user-modifiable read-only memory (ROM) that can be

erased and reprogrammed (written to) repeatedly through the application

of higher than normal electrical voltage generated externally or internally in the case of modern EEPROMs. EPROM usually must be

removed from the device for erasing and programming, whereas

EEPROMs can be programmed and erased in circuit. Originally,

EEPROMs were limited to single byte operations which made them

slower, but modern EEPROMs allow multi-byte page operations. It alsohas a limited life - that is, the number of times it could be reprogrammed

was limited to tens or hundreds of thousands of times. That limitation

has been extended to a million write operations in modern EEPROMs.In an EEPROM that is frequently reprogrammed while the computer is

in use, the life of the EEPROM can be an important design



consideration. It is for this reason that EEPROMs were used for configuration information,

rather than random access memory

Magnetic tape is a medium for magnetic recording, made of a thin

magnetizable coating on a long, narrow strip of plastic. It was developedin Germany, based on magnetic wire recording. Devices that record and

play back audio and video using magnetic tape are tape recorders and

video tape recorders. A device that stores computer data on magnetic

tape is a tape drive (tape unit, streamer).

Magnetic tape revolutionized broadcast and recording. When all radio was live, it allowed programming to be prerecorded. At a time when

gramophone records were recorded in one take, it allowed recordings in

multiple parts, which mixed and edited with tolerable loss in quality. Itis a key technology in early computer development, allowing

unparalleled amounts of data to be mechanically created, stored for long

periods, and to be rapidly accessed.

Today, other technologies can perform the functions of magnetic tape. In

many cases these technologies are replacing tape. Despite this,innovation in the technology continues and tape is still widely used.

Over years, magnetic tape can suffer from deterioration called sticky-

shed syndrome. Caused by absorption of moisture into the binder of the

tape, it can render the tape unusable.





� make the programming of applications easier by:

� hiding fragmentation.

� delegating to the kernel the burden of managing the memory

hierarchy; there is no need for the program to handle overlays explicitly.

obviating the need to relocate program code or to access memory with

relative addressing

RAM (Random Access Memory) is your computers "thinking space" and only functionswhile your PC is turned on. Contemplate yourself in the morning when you wake up and start loading programs you have developed over the years (like "get out of bed", "walk to the shower", "take shower", etc. etc.) from your own 'hard drive' to your own `RAM' and you will understand how your PC works. The part of your brain that, in PC vernacular, is `RAM', clears all information stored in it as you fall asleep and (unless youare prone to personal dreaming) does not `come alive' until you wake up the next morning.

RAM (also called "Real Memory") performs the critical function in your PC of absorbing data and interacting with your processor on all programs (operating system and applications) while your PC is turned on doing it's thing (or your thing). While you are

creating a document (making `inputs¶ from your keyboard and mouse), it is temporarily stored in real memory and exists only in RAM until you save it to your secondary memory device (hard drive). Simply, Primary Memory assembles data fromsecondary memory and user inputs, provides the data input `to' and receives dataoutput `from' your Central Processing Unit, and temporarily stores your work. If you lose power before you have `saved' your work, it's history!!

The main memory of the computer is also known as RAM, standing for R andom Access

Memory. It is constructed from integrated circuits and needs to have electrical power in order tomaintain its information. When power is lost, the information is lost too! It can be directly

accessed by the CPU. The access time to read or write any particular byte are independent of



whereabouts in the memory that byte is, and currently is approximately 50 nanoseconds (athousand millionth of a second). This is broadly comparable with the speed at which the CPU

will need to access data. Main memory is expensive compared to external memory so it haslimited capacity. The capacity available for a given price is increasing all the time. For example

many home Personal Computers now have a capacity of 16 megabytes (million bytes), while 64

megabytes is commonplace on commercial workstations. The CPU will normally transfer data toand from the main memory in groups of two, four or eight bytes, even if the operation it isundertaking only requires a single byte

PROGR AM MEMORY .

The program memory is divided into pages of 512 words. If the device has more than one page

of program memory, the page is selected with the page bits (PA0 and PA1) in the STATUSregister.

Page bits are only evaluated when a branch instruction is encountered.

If a part has only one page of program memory, the page bits are ignored. If the device has onlytwo pages of program memory, only PA0 is used. If the device has four pages, only PA0 and

PA1 are used. Page bit PA2 is not currently implemented in the PIC16C5X architecture so it isalways ignored.

The Program Counter, when no branch instruction is encountered, will increment normally

through the entire program memory array. When it reaches the last program memory location, itwill wrap around to 0.

The page select bits are not automatically updated by the processor when program executionflows onto another page

DATA MEMORY

The data memory is located on a physically separate internal bus from the program memory.

This means that instructions cannot be executed from data memory.

Some devices that have more than one bank of data memory.

The considerations for changing pages in program memory have nothing to do with the

considerations for changing pages (called banks) in data memory. They are separate operationsand are handled with different register page select bits located in the FSR .

Data memory banks are selected with bits 5 and 6 of the FSR .

The lower half of data memory (00h to 1Fh) is never banked for any device. No matter what

value is in the FSR , the lower half of the data memory can always be read.

For devices that have only one bank of upper data memory, the entire data memory array can beread without regard for the value in FSR

secondary memorySecondary memory (or secondary storage) is the slowest and cheapest form of memory. It cannot be processeddirectly by the CPU. It must first be copied into primary storage (also known as RAM ).

Secondary memory devices include magnetic disks like hard drives and floppy disks ; optical disks such as CDs andCDROMs ; and magnetic tapes, which were the first forms of secondary memory.



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Microprocessor Assingment

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