Timing diagram of 8086 microprocessor in minimum mode

In my previous post, I have explained  8086 microprocessor in minimum mode. This post explains the timing diagram of 8086 microprocessor in Minimum mode.

1. READ CYCLE TIMING DIAGRAM 

The read cycle begins in T1 with the assertion of ALE (Address latch enable ) and M/IO signal for memory or input-output process. During the negative going edge of the signal ,the valid address is latched on the local bus. The BHE or bus high enable and Ao signal addresses low , high or both bytes.

2. WRITE CYCLE TIMING DIAGRAM.

8086 microprocessor in minimum mode

Minimum mode in 8086 microprocessor :-
Microprocessor 8086 is operated in Minimum mode by strapping its MN/MX pin to logic 1.In this mode, all the control signals are given out by the microprocessor chip itself . There is a single microprocessor in the minimum mode system.
The figure below shows the microproceesor 8086 in minimum mode. The block digram shows various components in the systems like latches,transceivers,clock generator or i/o devices.
The latches that are used to separate the valid address from the multiplexed address are generally buffered utput D-type flip-flop,like 74lS373 . The latches are controlled by ALE. Transreceivers are bidirectional buffers and sometimes they are called data amplifiers.
DT/R indicates the direction of data. T means transfer in case of write and R means receiving data in case of write cycle.
20 address lines and 16 data lines is clearly shown in the figure below.

The working of the minimum mode in next post.

What is Discrete Memoryless Channel ?

Define :-  Discrete Memoryless Channel
A communication Channel may be defined as the path or medium through which the symbols flow to the receiver end. A  Discrete Memoryless Channel (DMC) is a statistical model with an input X and an output Y as shown in figure.

During each unit of time ,( the signaling interval ) , the channel accepts an input symbol from X, and in response an output symbol from Y. The channel is sais to be "discrete" when the alphabets of X and y are both finite.
Also,it is said to be "memoryless" and not on any of the previous inputs.

What is Entropy in Information Theory?

What is the concept of entropy?

A communication system transmit a long sequence of symbols from an information source that is , a communication system not deal with a single message but with all possible messages.
Thus we are more interested in the average information that a source produces rather than the information content of a single source.
Hence entropy is the average information per symbol .
Or   Average information per individual message.

It is a measure of uncertainty in a random variable.

Assumptions:
1 ) The source is stationary so that the probabilities remain constant with time.
2 ) The successive symbols are statistically independent  and come from the source at an average rate of being symbols per second.

Mathematical expression :

H(X) = E(I(x)) = -∑P(x)logP(x)  bits/symbol
Where H (X) is known as entropy of the source X.



Entropy for Binary source:

Information as a measure of uncertainty | Information in communication systems

In my previous post, I gave you Introduction about Information Theory. In this post I am going to tell about
Information , its unit, its uncertainty and mathematical relation.
First coming over to the amount of information contained in a message. Have you ever wondered about this?
Let us take an example : Suppose you are planning a tour a city located in such an area where rainfall very rare.
To know about the weather forecast you will call the weather bureau and may receive one of the following information:
1) It would be hot and sunny.
2) There would be rain.
3) There would be a cyclone.
It may be observed that the amount of information received is clearly different from the three messages. The first message, just for instance, contains very little information because the weather in a desert city in summer is expected to be hot and sunny for most of the time.
The second message i.e. rain contains more information because it is not an event that occurs often.
The third message i.e. cyclonic storms will contain the maximum amount of information as compared to the previous two. This is because the third event rarely happens in the city.
Thus,
There is an Inverse relationship between the probability of an event and information associated with it.

 I(x)=f[1 / p(x)]
Where I (x) represent the information and f means (it a function of ) while 1 / p (x) represents the inverse of probability.

Properties of Information content I (x) :
1)   I (x) = 0  For p (x) =1
2)   I(x) ≥ 0
3)   I (x_i)>1(x_j) if P(x_i)<P(x_j)
4)

NEXT POST : Entropy and its poperties.                                                                              

What is information Theory?

Information Theory is branch of probability theory which can be applied to the study of the communication systems.
It is a broad mathematical discipline and it has made fundamental contributions not only to communications but also computer science,statiscal physics and probability and statistics.

This concept of Information Theory was invented by communication scintists while they were studying the statistical structure of electronic communication equipments.
A basic Communication system consists of three components:

1 ) Transmitter
2 ) Medium or channel
3 ) Receiver

When the communique or message is measureable Like current or voltage then the study of communication system is very easy but When the communique is Information ,then the study becomes quite difficult.
So, Information theory studies all these kind of Questions regarding the information ,whats its unit and how it is  transferred.

A communication system is Non-deterministic i.e. thst means it has statiscal nature.Thus a communication system has uncertainity or in other words a communication system possesses unpredictability.
The amount of information(it is a parameter) associated with an event can not be determined.

NEXT POST : Information as a measure of uncertaininty.

Array processors -SIMD Array processor

In my previous post i discussed What are array processor and its first type that is the attached array processor that is used fr carrying out scientific numerical applications by attaching an auxillary processor along with General host computer. READ full post here.
IN this tutorial i am going to tell about SIMD ARRAY PROCESSOR :
SIMD stand for Single instruction multiple data Instruction.
It consists of multiple processing units or elements that are operating in parallel and are synchronized to perform the same task  or operation under the control of a common control unit. HENCE the name is single instruction multipla data.
  A general BLOCK DIAGRAM IS shown below.

 

Thus it contains a set of processing elements (PE'S ) ,each having a local memory M. Each processor element includes an ALU. a floating arithmetic unit,and working registers.The master control unit controls the operation in the procssor elements.

AN INDIVIDUAL PE(PROCESSING ELEMENT)

Each PE has its own local memory. MAIN MEMORY IS used for the storage of program while master control unit  controls the operations in the processor elements.it decodes the instructions and decde how a particular  instruction will be executed.
THE SCALER instructions is executed by the control unit itself while the vector instructions are send to all the PE'S  simulataneously.


BEST KNOWN SIMD ARRAY PROCESSOR IS THE ILLIAC IV COMPUTER..

What is ARRAY PROCESSOR ? Its types

ARRAY processor is  a processor that performs computations on a large array of data.
It is also called vector processor.(It execute one instruction at a time but on array of data.)
Array processor is of two types:-

1) ATTACHED ARRAY PROCESSOR
2) SIMD ARRAY PROCESSOR

Coming over attached array processor - In this an auxillary processor is attached to a general purpose computer.It enhances the performance of the host computer in specific numerical computation tasks.
* It provides vector processing for complex scientific applications.
* This attachment is done by parallel processing i.e. it contains  one or more pipelined floating point adders and multipliers.
Can be programmed by user.



GENERAL PURPOSE
COMPUTERS                <------------->  I/O INTERFACE  <-------------->ATTACHED ARRAY PRO.
          |                                                                                                                      |
          |                                                                                                                      |
          |                                                                                                                      |
  MAIN MEMORY        <------------------------------------------------------>        LOCAL MEMORY

The attached array processor is attached to host computer by a input-output interface or controller and The data for the attached processor are transferred from main memory to a local memory through a high speed bus.
NEXT POST. SIMD ARRAY PROCESSOR

continue reading  SIMD PROCESSOR....