The document discusses programming PIC microcontrollers using C and assembly languages. It states that assembly language produces smaller programs but is more tedious than C. C programs require a cross-compiler like MPLAB to convert C code into machine language for the target PIC microcontroller. MPLAB includes header files containing function declarations to program ports, timers, and other microcontroller features. The document provides examples of using basic programming constructs like if/else statements, loops, and library functions with a PIC microcontroller.

2.  Main concern is program memory space.
 Assembly language programming produces
hex file that is much smaller than that
produced by programming in C.
 Assembly language is tedious and time
consuming.

3.  Programming in C is less tedious and less
time consuming as compared to assembly
language
 Easier to modify and update
 Portable to microcontrollers with little
modifications
 C also provides some library functions.

4.  We write a program in C, we need a compiler
to convert it into machine language.
 here we use Pentium processor.
 But our compiler has to make code for
PIC18F877 processor for C program.
 Such a compiler is called as cross compiler.
i.e produces code for another processor and
not the system in use.
 MPLAB is such a compiler used for
microcontrollers of PIC series.

5.  MPLAB has header files for every
microcontroller.
 Header files contain variable declarations,
macro definitions, special function registers
etc.
 “16F877A.h” is the header file for PIC
18F877.
 This file has many inbuilt C functions to
perform various tasks like giving output to
port and read data from port.

6. #include “16F877A.h”
void main()
{
output_C(85)
}
 Function output_x() is used to output data on
port ‘x’

7.  Data types:
- int
- signed int
- unsigned int
- char
- signed char
- unsigned char

8. #include “16F877A.h”
void main()
{
int x;
x=input_A();
output_B(x);
}

9. for(initializations;condition;inc/dec/update)
{
-
-
-
statements;
-
-
}

10. #include “16F877A.h”
void main()
{
int x;
for(x=1;x<=10;x++)
{
output_B(x);
delay_ms(100);
}
}

11. while(condition)
{
-
-
statements;
-
-
}

12. #include “16F877A.h”
void main()
{
int x;
x=1;
while(x<=10)
{
output_B(x);
x++;
}
}

13. do
{
-
-
statements;
-
-
}while(condition);

14. #include “16F877A.h”
void main()
{
int x;
x=1;
do
{
output_B(x);
delay_ms(100);
x++;
}while(x<=10);
}

15. if(condition)
{
-
-
statements;
}
else
{
-
-
statements;
}

16. if(condition)
{
-
-
statements;
-
-
}

17. if(condition)
{
statements;
}
Else
{
if(condition)
{
statements;
}
else
{
if(condition)
{
statements;
}
}
}

18. switch(expreesion/variable)
{
case label1: statements;
break;
case label2: statements;
break;
case label3: statements;
break;
default: statements;
}

19. while(condition)
{
-
-
break;
-
-
}
for(init;cond;inc)
{
-
-
break;
-
-
}

20. while(condition)
{
-
-
continue;
-
-
}
for(init;cond;inc)
{
-
-
continue;
-
-
}

21. Library functions Operation done
delay_us(x) Generates delay of x microseconds
delay_ms(x) Generates delay of x milliseconds
output_p(x) Outputs parameter ‘x’ on output port ‘p’
Five ports available are: A,B,C,D,E
input_x() Returns the value on input port x

22. Operator Representation
Unary minus _
Logical not !
Bitwise not ~
Increment operator ++
Decrement operator --
Arithmetic operators +,-,*,/,%
Shift operators <<,>>
Assignment operators =,+=,-=

23.  Local variables
- limited to the function in which it is
defined
 Global variables
- it is accessible anywhere in the program.

24.  Functions/Recursive functions
 Arrays
 Multidimensional arrays
 Pointers
 Strings

25.  Address of operator (“&”)
p=&x;
address of variable x is copied in pointer p
 Value of operator (“*”)
y=*p;
value of variable pointed by pointer p is
stored in variable y