
C is general-purpose structured programming
language or high level language.

It was developed by Dennis Ritchie in 1970s at Bell
laboratories.

C supports a large no. of operators and a large no.
of library function.

C is most popular language used for system
programming ,such as development of compilers,
interpreters , assemblers , operating system like
UNIX.
A typical C program has 3 sections:
#include< stdio.h > //Header file section
#include< stdio.h >
void main( )
{
int a,b; //Type declaration section
//Instruction section
}
#include <stdio.h>
main()
{
printf(“Hello World”);
}

A library function is a self-contained program
that carries out some specific as well as
defined tasks.

The function prototype or the reference is
defined in the header files section so we have
to include them in the beginning of program.

Example: #include, #define

The statements used to change the control
flow in a program are called the control
statements or control structures in C.

Control statements:
 Logical if structure
 If-else structure
 Nested if-else
 Unconditional goto statement
 Switch structures

The logical if structure checks a given logical
condition and transfers the control accordingly.
Syntax:
Example:
If(condition)
{
Statement;
}
if(x==3)
{
Y=2*x;
}
#include <stdio.h>
int main()
{
int a=1;
If(a==1)
{
printf(“true logic”);
}
If(a==0)
{
printf(“false logic”);
}
return 0;
}

The if-else structure is more useful than
logical if structure.
Syntax:
if(expression)
{ S1; }
else
{ S2; }
Example:
if(i==0)
{ s=s+1; }
else
{ s=s-1;
}
#include <stdio.h>
int main()
{ int a=1;
If(a==1) {
printf(“true logic”); }
else
{
printf(“false logic”); }
return 0;
}

C provides three loop structures to perform
looping operations or iterations, in which a
set
of
statements
can
be
repeatedly
executed as long as condition is satisfied.
Loops are:
while
Do while
For

It is similar to the while-loop structure
except that the condition is checked at
the end of the loop.
Syntax:
do
{S1;
} while(condition);
Example:
do
{ i=i+1;
} while(i <2);
#include <stdio.h>
int main()
{int i=0;
do{
printf(“value of i=%d”,i);
i++;
}while(i<10);
return 0;
}
In while-loop structure condition
checked at the starting of the loop.
Syntax:
while(condition)
{ s1;
}
Example:
while(i>0)
{ j=j+1;
}
is
#include <stdio.h>
int main()
{int i=0;
while (i<10){
printf(“value of i=%d”,i);
i++;
} return 0;
}

The expr1 is the statement assigning an initial
value to a variable,expr2 is a logical expression
and expr3 is a statement that is used to alter the
value was assigned in the initial expression.
Syntax:
For(expr1;expr2;expr3)
{ statements;
}
Example:
For(i=1;i<=5;i++)
{ j=j+1;
}
#include <stdio.h>
int main()
{ int i;
for(i=0;i<10;i++)
{
printf(“value of i=%d”,i);
} return 0;
}




0;
1;
Binary to Decimal Conversion
Decimal to Binary Conversion










0-9,
A,
B,
C,
D,
E,
F
Conversion
Decimal to Hexa decimal and vice versa
Binary to Hexa Decimal and vice versa


0-7
Conversion







~ One’s Complement (unary operator)
>> Right Shift
<< Left Shift
& Bitwise AND
| Bitwise OR
^ Bitwise XOR (Exclusive OR)
Bitwise Compound Assignment Operators(eg.
<<=, >>=,|=,&=, and ^=)
#include <stdio.h>
int main()
{ unsigned char ch=32;
unsigned char dh;
dh=~ch;
printf(“~ch=%d\n”,dh);
printf(“~ch=%x\n”,dh);
printf(“~ch=%X\n”,dh);
return 0;
}
Ch=11010111;
Ch>>1 gives output 01101011;
Ch>>2 gives output 00110101;
#include <stdio.h>
void showbits(unsigned char);
int main()
{ unsigned char num=225,i,k;
printf(“\n Decimal %d is same as hexa
%x”,num,num);
for(i=0;i<=5;i++)
{k=num>>i;
printf(“\n %d right shift %d gives %x”,num,I,k);
//showbits(k);}
return 0;}


Same as right shift operator
<<



Bitwise OR operator (|)
Bitwise AND operator (&)
Bitwise XOR operator(^)










void showbits(unsigned char n)
{ unsigned char i,k,andmask;
for(i=7;i>=0;i--)
{ andmask=1<<i;
k=n & andmask;
If(k==0)
printf(“0”);
else printf(“1”);
}
}
ROBOT:

Robot is a machine that gathers information
about its environment(senses) and uses that
information to follow instructions to do work.
MICROCONTROLLERS:

Microcontrollers is a single chip computer
containing a processor core , memory and
programmable input/output peripherals.

DDRX: defines whether the port will act as
i/p port or o/p port.
1 use for output
0 use for input
Example:
DDRA
DDRA
DDRA
DDRA
=
=
=
=
0b11111111;
0xFF;
1;
010;
(binary)
(hexa decimal)
(decimal)
(octal)

DDRX.Y:
Define individual pin (pin Y of port X) acts
as the i/p pin or the o/p pin
Example:
DDRA.3=1;
pin 3 of port A is o/p port.

PORTX:
Use to assign value to PORTX.
Example:
PORTA=27
decimal value 27 is assigned to the portA.

PORTX.Y:
Use to assign value to individual pins(y) of
any port (X).
Example:
PORTA.0=1
assign value 1 to the pin0 of the port A.

PINX:
Read 8-bit integer value from the port X.
Example:
X=PINA;
Read the 8-bit integer value from the portA.
0<X<255

PINX.Y :
Read 1-bit value (individual pin value) from PORTX.
Example:
X= PINA.2; ( value may be 0 or 1)

PORTA is different from port A:
Port A
uC
P
O
R
T
A
D
D
R
A
P
I
N
A
External
world
PROGRAMS:
A program to o/p 33 (hex) on Port D.
#include <mega16.h>
void main( )
{
DDRD=0xFF;
PORTD=0x33;
}
PROGRAMS:
A program read pins 2 and 7 of Port A.
#include <mega16.h>
void main( )
{
unsigned int x,y;
DDRA=0b01111011;
x=PINA.2;
y=PINA.7;
}
GND
+
+ VE
Longer leg is +ve Terminal
0
1
-
+
P
o
r
t
A
For glowing LED
PORTA.0=0 (GND)
PORTA.1=1 (+V)
Or
PORTA=0b00000010;
Or
PORTA=0x02;
void main()
{
DDRB=0XFF;
while(1)
{
PORTB=0XFF;
delay_ms(100);
PORTB=0X00;
delay_ms(100);
}
}