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Introduction
C - Language is very efficient language to use especially
with the hardware. It is similar to the languages we used to
write before with little bit differences. And it has also
1)
2)
3)
4)
5)
6)
Loops.
Conditional Statements.
Switch Cases.
Variables and Data types.
Objects.
Arrays.
It is similar to the other languages we have learnt before
which makes us familiar with the syntax to a further limit.
Outline
1)
Software installation
2)
Include statement and definition statements
3)
Main method and file structure
4)
Variables and data types
5)
Arrays
6)
Conditional statements
7)
Loops and iteration statements
8)
Registers names and data direction
9)
Methods
10)
Operators
11)
Examples
(1) S/W Installation
This software is called MikroC for PIC which you can download from
the following link
http://www.mikroe.com/eng/products/view/228/mikroc-pro-for-avr/
It would be used to simulate C-programs in PIC microcontrollers
(2) Include and definitions
Do you remember this line
import java.io.*;
In the previous java courses we used this line to import
some predefined classes in java to be used in the active
class we are working through
But, How we could do the same in C- Language?
#include <h_file> ;
It could be done using the #include statement to include one
of the header files (h_files) that have all the microcontrollers
predefined functions and register names
(2) cont.
#include <file.h>
y
r
a
r
b
C- Li
Header File
Predefined elements
are ready for the
class
C- Class
(2) cont.
Also You Can FIND in C- Language
#define X Y ;
It is used to define variable called X to have the same value
or behavior as variable Y and this can be realized in
Example (2.1)
#include <pic16f877a.h>
/* this makes the header file for the PIC16f877 ready to
be used in the C-class */
#define LED PORTC ;
/* defines LED variable in the class to work as PORTC so
what happens to LED will be applied on PORTC */
(3) Class structure and
The C Class consist of the following
main
#include <pic16f877a.h>
#define LED PORTC ;
; // header file include
// define LED as PORTC
void main ( void )
// main method
{
// main method implementation and print test
printf(hellow World);
}
Main method is the one responsible for organizing the
class methods and variables. It can call any other
method inside
void means it wont return any value because it is the
main one (optional to write between brackets)
(4) Variables and Data
types
(4) cont.
(4) cont.
Variables and Data Types
(4) cont.
Integer
int is used to define integer numbers
Int
count = 5;
float
FLOAT is used to define floating point numbers
float
count = 5.6;
char
char is used to define characters
char
letter = x;
(5) Arrays
Arrays is the group of elements saved in one group and each element has an
index of its location that contains its value
All of its elements should have the same type
Index always starts from zero
45
0
int [6] x ;
/* Creates empty array of length 6 cells */
int [6] x = {12,45,3,7} ;
/* Creates array of length 6 cells shown in
this page where the cells values are the
values between the
12
0
the curly braces */
/* notice that the rest of cells that not
declared yet will have a value of 0
(default value of the integer type) */
0
3
0
7
0
0
(5) cont.
Two Dimensional Arrays
int [6][2] x ;
12
20
10
/* Create empty 2D-array of 6 cells */
x[1][1] = 12 ;
/* assign value 12 to cell (1,1)*/
x[3][0] = 20 ;
/* assign value 12 to cell (3,0)*/
x[5][1] = 10 ;
/* assign value 12 to cell (5,1)*/
Int temp = x[1][1] ;
/* temp in memory will have value of 12*/
(6) Conditional Statement
Conditional statement gives you an
option
to
make
branches
in
the
evaluated condition .. If the condition is
true it would take certain otherwise it
would take the other one like the
following flow chart.
int num = 6 ;
if ( num < 0)
{
printf(negative);
}
else
{
printf(positive);
}
(6) cont.
Conditional statement has two forms
switch
If-else
int month= 6 ;
int num = 6 ;
switch (month)
{
if ( num < 0)
case 1: printf(JAN);break; {
case 2: printf(FEB);break;
printf(negative);
. . .
}
case 12: printf(DEC);break; else
default: printf(error);
{
break;
printf(positive);
}
}
Used for many branches instead Of nested if-else
Abscence of break will prevent the instruction to be printed and it will print the
statement that has the first break.
In if-else statement the else is related to the closest if
More than one statement inside the if part or else part will need curly braces for
the instructions
(7) Iteration Statements
Iteration Statement gives you chance
to repeat certain group of operations
more than one time if certain conditions
validates true otherwise the iteration
process will terminate according to the
flow chart
Iteration Operations needs 3 main
basic steps for their operation:
1)
Initialization
2)
Condition
3)
Operation and update
(7) cont.
Iteration statement has three forms
while
int x = 5;
while ( x > 0 )
{
printf(positive);
}
for Do-loop
operation
iteration
evaluates
of
the
process
that
condition
before
looping
Execute the operation at least
one time before evaluating the
int num = 6 ;
{
printf(positive);
}
do ( x < 0 )
for (int x = 5 ; x < 0 ; x --)
{
printf(positive);
}
Normal
condition
O(n+1) not like the while loop
that has O(n)
The
simplest
form
of
the
iteration process and the most
common used in counters
Update may be incrementation or decrementation or any other form
(8) Register and Data
TRISX is used to define the direction of register X data to work as input or output
and it is the register carrying the direction of the port X
PORTX is used to define the data of port X and it is the register carrying the data
of this port
PORTXbits.RX4 is used to define the data of port X bit number 4 for example
Void main ( void )
{
TRISB = 0 ;
// Make port B an output
TRISC = 1 ;
// Make port C an input
PORTB = 0 ;
// Assign value zero to port B
PORTCBITS.RC4 = 1; // Assign value 1 to bit 4 port C
}
(9) Methods
Sometimes you need to break your program to smaller parts in order to
have flexible and reliable program because the first step to solve any
problem is to break it down to solvable smaller problems
So we have the main method the organizer to the class that will invoke
any other method created inside the class
Take Care that : creating and calling methods in C is a little bit different
from JAVA
(9) Cont.
#include <16f877a.h> ;
int add (int x , int y);
// the definition of the method should be written here
Void main ( void )
{
int a = 5;
int b = 7 ;
printf(the result is = + add(a , b));
}
// method to be invoked by the main method in C- class
int add (int s , int r )
{
int z = s+r;
return z ;
}
(10) Operators
Assume we have to operands a and b
Logical operators
Comparison operators
Bitwise operators
(10) Cont.
Assume we have to operands a and b
Compound operators
Arithmetic operators
(11) Example (1)
Write a C18 program to toggle all the bits of port B
continuously
#include <16f877a.h> ;// for TRISB and PORTB declarations
void main(void)
{
TRISB =0;
// make Port B an output
for ( ; ; )
// repeat forever
{
PORTB = 0x55;
PORTB = 0xAA;
}
}
like while(ture)
(11) Example (2)
Write a C18 program to send values 00-FF to port B
#include <16f877a.h> ;// for TRISB and PORTB declarations
void main(void)
{
unsigned char z;
TRISB =0; // make Port B an output
for (z=0;z<=255;z++)
PORTB =Z;
while (1);
}
// needed If running in hardware
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