Mohammed Fathy

The pins of a 8085 microprocessor can be classified into seven 
groups. 
1.Address bus 
A15 – A8 at pin no. 28 to pin no. 21, it carries the most significant 8-
bits of memory and I/O address. The microprocessor can address 
directly 65536 memory locations or 64k memory locations using 16- 
address lines (A15-A0). Pin no. 28 to pin no. 21 give us the higher 
order 8-bits of the address (A15-A8). 
AD7–AD0 at pin no. 19 to pin no. 12 are used for dual purpose. It is 
time multiplexed lower 8-bit address bus (A7-A0) and 8-bit data bus 

Lecture-5  
Characteristics of Memory:  
In the broad sense, a microcomputer memory system can be logically 
divided into three groups:  
1) Processor memory  
2) Primary or main memory  
3) Secondary memory  
• Processor memory refers to a set of internal registers. These registers hold 
temporary results when computation is in progress.  
• Primary memory or the main memory is the internal memory to store both 
program and data. The processor can access these memories directly.  

Basic Matrix Functions:- 
magic(n) 
returns an n-by-n matrix constructed from the integers 1 through n^2 with 
equal row and column sums. The order n must be a scalar greater than or 
equal to 3.

>> M = magic(3)  

M =   
   8    1    6  
   3    5    7  
   4    9    2

End as a subscript   
To access the last element of a matrix along a given dimension, use  
end as a subscript. This allows you to go to the final element without  
knowing in advance how big the matrix is. For example:  

>> q = 4:10    
q=   
4   5   6   7   8   9   10    

>> q(end)   
ans = 10  

 
>> q(end-4:end)    
ans = 6   7   8   9   10  

 
>> q(end-2:end)   
ans = 8   9   10  

The Colon Operator 
The colon" : " is one of MATLAB’s most important operators. It occurs 
in several different forms. The expression 
>>1:10 
is a row vector containing the integers from 1 to 10 
1 2 3 4 5 6 7 8 9 10 
To obtain nonunit spacing, specify an increment. For example, 
>>100:-7:50 
is 
100 93 86 79 72 65 58 51 
• End as a subscript 
To access the last element of a matrix along a given dimension, use end 
as a subscript. This allows you to go to the final element without knowing 

insert and delete rows and columns:

>> A 
A =

= [1 2 3 ; 4 5 6 ; 7 8 9]

1 2 3 
4 5 6 
7 8 9

>> A(2,2)

an

s

= 5

>> A(3,3)

an

s

= 9 

Lecture2: 
A first steps: 
To get matlab to work out 1 + 1, type the following at the prompt: 
1+1 
matlab responds with 
ans = 2 
The answer to the typed command is given the name ans. In fact ans is 
now a variable that you can use again. For example you can type 
ans*ans 
to check that 2 × 2=4: 
ans*ans 
ans = 4 
Matlab has updated the value of ans to be 4. 
The spacing of operators in formulas does not matter. The following 
formulas both give the same answer: 
1+3 * 2-1 / 2*4 1+3*2-1/2*4 

1- Introduction:

MEMORY: 
It is a storage device. It stores program instructions, data and the results. 
There are two kind of memories; 
semiconductor memories & magnetic memories. (1): Semiconductor 
memories are faster, smaller, and lighter and consume less power. 
Semiconductor memories are used as the main memory of a computer. (2): 
Magnetic memories are slow but they are cheaper than semiconductor 
memories. Magnetic memories are used as the secondary memories of a 
computer for bulk storage of data and information’s. 

The Bussed Architecture for Microprocessor: 
The first question is what is a ‘Bus’? Bus is a group of parallel lines that 
connect two or more devices as shown in fig.2. It carries information in bits. 
Whenever processor (CPU) needs to access any memory or I/O device of 
the microcomputer system.