What is random access memory, Computer Engineering

Assignment Help:

Q. What is Random Access Memory?

We will discuss RAM as an example of sequential circuit. A memory unit is a collection of storage cells or flip flops along with associated circuits needed to transfer information in and out of device. The access time and cycle time it takes are constant and independent of location therefore the name random access memory.

172_What is Random Access Memory.png

Figure: Binary Cell

RAMs are arranged (logically) as words of fixed length. Memory communicates with other devices by data input and output lines and address selection lines and control lines which specify direction of transfer.

Now let's try to understand how data is stored in memory. The internal construction of a RAM of 'm' words and 'n' bits per word comprises m ×n binary cells and connected circuits for detecting particular words. Figure below displays logic diagram and block diagram of a binary cell.

The input is fed to AND gate 'a' in complemented form. Read operation is denoted by 1 on read/write signal. Thus during read operation only 'AND' gate 'c' becomes active. If cell has been selected then output will become equivalent to state of flip flop it implies that data value stored in flip flop is read. In write operation 'a' & 'b' gates become active and they set or clear J-K flip flop relying upon input value. Please note in case input is 0 then flip flop will go to reflected in state of flip-flop. So we say that input data has been stored in flip-flop or binary cell.

Figure below is extension of this binary cell to an IC RAM circuit where a 2×4 decoder is used to select one of the four words. (For 4 words we require 2 address lines) Please note that every decoder output is connected to a 4 bit word and read/write signal is given to every binary cell. Once decoder selects word, read/write input tells operation. This is derived using an OR gate since all non-selected cells will generate a zero output. When memory select input to decoder is 0 none of words is selected and contents of cell are unchanged irrespective of read/write input.

1320_What is Random Access Memory1.png

Figure: 4 × 4  RAM


Related Discussions:- What is random access memory

Future trends of microcontrollers, Currently microcontrollers are embedded ...

Currently microcontrollers are embedded within most products, typical uses are in Camera's for auto focus and display drivers, Laser printers to compute fonts and control printing.

Slot machine, A special Slot Machine is introduced in a new casino; this ma...

A special Slot Machine is introduced in a new casino; this machine has a digital interface of a 3X3 grid. An interface button named as SPIN for making the machine spin. There are f

Determine the nand gate, Find out the two inputs when the NAND gate output ...

Find out the two inputs when the NAND gate output will be low. Ans. The output of NAND gate will be low if the two inputs are 11. The Truth Table of NAND gate is shown

Not dragged and dropped onto the form, I have to make a quiz machine progra...

I have to make a quiz machine program in in Visual Basic with the following: A menu strip that must be formed programmatically (ie NOT dragged and dropped onto the form). There

What is a session in php, A session is a logical object formed by the PHP e...

A session is a logical object formed by the PHP engine to permit you to preserve data across subsequent HTTP requests. There is only one session object available to your PHP scr

Structured analysis and design approach, Q. Structured Analysis and Design ...

Q. Structured Analysis and Design Approach? The objective of structured system analysis and design is to reduce maintenance time as well as effort. Modeling is the act of drawi

Ethernet 10 base 2 is an example of which topology, Ethernet 10 Base 2 is a...

Ethernet 10 Base 2 is an example of               network topology. (A)  Bus                                           (B)  Ring (C)  Star

Boiler troubles, Differences between internal and external treatment in boi...

Differences between internal and external treatment in boiler

What is "at exit-command", What is "at exit-command:? The flow logic K...

What is "at exit-command:? The flow logic Keyword at EXIT-COMMAND is a special addition to the MODULE statement in the Flow Logic .AT EXIT-COMMAND lets you call a module befor

E brokerage facilitates search & retrieval of information, E Brokerage faci...

E Brokerage facilitates search & retrieval of Information The success factor of a brokerage is its ability to retain existing clients and to enhance their satisfaction by effec

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd