1. Embedded Systems
Eng. Mohammed Sokkaree

2. Agenda
• Introduction to embedded Systems
• Why embedded C
• Interview questions
• Q&A

3. Computing Systems

4. What’s ES?
• System designed to do one or a few dedicated
and/or specific functions.
• combination of computer hardware and software
▫ Mp3 player
▫ Mobile
▫ Medical testing systems
▫ Anti-Lock Brakes

5. Embedded SW
• Portability
• Optimization
• Quality
• Readability
• Complexity
• HW Compatibility “ HW knowledge”
• Min. Resources

6. Why embedded C?

7. Question 1
RTD

8. Question 1
• Real time System
▫ Hard
▫ Soft
• CBT

9. Question 2
SWE

10. Question 2
• Testing
▫ Types of testing
• Debugging

11. Question 3
Pointers

12. Pointers Pointers & Pointers
• Using the variable a, give definitions for the
following:
▫ a) An integer
▫ b) A pointer to an integer
▫ c) A pointer to a pointer to an integer
▫ d) An array of 10 integers
▫ e) An array of 10 pointers to integers
▫ f) A pointer to an array of 10 integers
▫ g) A pointer to a function that takes an integer as an
argument and returns an integer
▫ h) An array of ten pointers to functions that take an
integer argument and return an integer

13. Answer
• a) int a; // An integer
• b) int *a; // A pointer to an integer
• c) int **a; // A pointer to a pointer to an integer
• d) int a[10]; // An array of 10 integers
• e) int *a[10]; // An array of 10 pointers to integers
• f) int (*a)[10]; // A pointer to an array of 10 integers
• g) int (*a)(int); // A pointer to a function a that takes
an integer argument and returns an
integer
• h) int (*a[10])(int); // An array of 10 pointers to
functions that take an integer argument and return an
integer

14. Question 4
Macros

15. Question 4
Functions Function like
macros
How it works
Input arguments

16. Question 4 (Cont.)
• Write a macro to set the MSB
#define MSB(X) ((X) | (1 << ((sizeof(X)<<3) -1))

17. Question 5
Variables

18. Question 5
• Local
• Global
• Static
• Extern

19. Question 6
Tracing

20. Question 6
int main() X Y
2 1
{
int x=1,y=1; 3 1
for(;y;printf("%d %dn",x,y)) 4 1
y=x++<=5; 5 1
return 0; 6 1
7 0
}

22. Thank you

23. Connect via LinkedIn
http://eg.linkedin.com/in/engmohammed

24. Hi all,
I have a basic C programming query.
For the program,
#define MAX(x,y) (x)>(y)?(x):(y)
void main( )
{
int i=10, j=5, k=0;
k=MAX(i++,++j);
printf("%d %d %d",i,j,k);
}
I get the output as 12,6,11
whereas, when I modify the program as below
int max_fn(a,b);
void main( )
{
int i=10, j=5, k=0;
k = max_fn(i++,++j);
printf("%d %d %d",i,j,k);
}
int max_fn(a,b)
{
return((a)>(b)?(a):(b));
}
In this case, I get the output as 11,6,10.

25. http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html