Digital logic,Number system-Binary to hex, memory, and basic concept of programming language.

1.  Basic Concept of Digital Logic
 Number system conversion
Binary to Hex
 Memory
ROM and RAM
 Basic Concept of Programming Language
High level language
Low level language
Machine level language

2. Analog Signal: A signal is said to be analog if it is continuous in nature.
All naturally occurring phenomenon are analog signals.
Eg: Speech, temperature, velocity, etc
Digital Signal: A signal is said to be digital if it is discrete in nature.(i.e. not continuous)
Digital signal is represented by 0 and 1.
For positive logic
0=low(0 to 0.1V)
1=High(3.5 to 5V)

3. Logic Gates:
NOT gate : It complements the input.
AND gate : Output is high only
When both inputs are high

4. Logic Gates:
OR gate : Output is high when any one of the input is high.

5. Logic Gates:
NOR gate : It is the complement of OR gate.

6. Logic Gates:
NAND gate : It is the complement of AND gate.
NAND gate and NOR gate are known as Universal gates.

7. Binary to Hexadecimal

8. Read Only Memory (ROM)
Non-volatile Memory
Random Access Memory (RAM)
Volatile Memory
Bit= Either 0 or 1
4 bit= 1 nibble
8 bit= 1 byte
1024 bytes= 1 kilobyte (kb)
1024 kilobytes= 1 megabyte (mb)
1024 megabytes= 1 gigabyte (gb)

9. High level language ( C programming)

10. HEADER FILE
MAIN PROGRAM
{
Variables declaration;
STATEMENT;
…………………….
……………………..
}
SUB PROGRAM
{
STATEMENT;
…………………..
………………………..
}

11. ‘#include’ known as preprocessor directive.
It tells the C processor to look for a file to be compiled.
stdio.h , conio.h , reg51.h etc… are header files.
Reg51.h ,reg52.h header files are used for microcontroller
programming
Examples:
#include<stdio.h> ,#include<reg51.h>, etc...
 #define pi=3.14

12. #include<stdio.h>
#include<conio.h>
Void main()
{
Printf(“simple example of c programing”);
getch();
}

13. If-else statement
Syntax : Flow chart:
If(condition)
{
statement
…………………
}
else
{
Statement
……………..
}

14. Example:
#include<stdio.h> //header file
#include<conio.h>
Void main()
{
Int a,b; //variable declaration
Printf(“Inputs two numbers”);
Scanf(“%d%d”,&a&b);
If(a>b)
{
Printf(“%d” ,a); //display a
}
Else
{
Printf(“%d” ,b); //display b
}
Getch();

15. Nested If else
Syntax:
If(condition)
{
Statement
..………
}
Else if(condition)
{
Statement
……….
}
else
{
……
}

16. #include<stdio.h>
#include<conio.h>
Void main()
{
int a,b,c;
Printf(“give the value of a b&c”);
Scanf(“%d%d%d”,&a,&b,&c);
If(a>b&&a>c)
{
printf(“a is greater”);
}
Else if(b>a&&b>c)
{
printf(“b is greater”);
Else
{
Printf(“c is greater”);
}
Getch();
}

17. While Loop
Check condition first.
If condition true execute body.
Otherwise execution goes to out of loop
Syntax: Flow chart:

18. Example:
#include< stdio.h >
#include< conio.h >
Void main()
{
int i=o;
while(i<10)
{
printf(“%d”,i);
i++;
}
getch();
}

19. Execute body first
Check condition
Repeat until expression is true
Syntax: Flow Chart:

20. Example:
#include< stdio.h >
#include< conio.h >
Void main()
{
int i=o;
do
{
printf(“%d”,i);
i++;
}while( i<10);
getch();
}

21. Generalized form of While loop.
Most useful loop.
Syntax:
For(Initialization ; Condition ; Increment/decrement)
{
Statement 1;
statement 2;
………………..
}

22. Flow Chart:

23. Example:
#include< stdio.h >
#include< conio.h >
void main()
int i;
for( i=0;i<10;i++)
{
printf(“%d”,i);
}
getch();
}

24. It is a Multi -way decision statement.
Syntax:
switch(n)
{
case 1:
{
statement 1;
break;
}
case 2:
{
statement 2;
break;
}
}
.

25. Decleration
Syntax: return_type function_name(data _type);
Eg. Float sum (int,int);
Call
Syntax: function_name(variable);
Eg. Y=sum(a,b);
Defination
Syntax: return _type function _name(data_type Variable)
{
Statement;
……………….
Return(………….);
}
Eg. Float sum (int a,int b)
{
int c ;
c=a+b;
return c;
}

26. Example
#include<stdio.h>
#include<conio.h>
Int sum(int,int);
Void main()
Int a,b,c;
Printf(“Enter two nos”);
Scanf(“%d%d”,&a,&b);
c=sum(a,b);
print(“sum=%d”,c);
getch();
}
int sum(int a,int b)
{
int d;
d=a+b;
return d;
}