Embedded System Interview Questions and Answers, Embedded System Interview Questions and Answers Freshers, Embedded System Interview Questions and Answers, Embedded System Interview Questions

Before getting on to the Embedded System interview questions, the student must know that the Embedded System is a continuously varying field which needs the students as well as professionals to upgrade their skills with the new features and knowledge, to get fit for the jobs associated with Embedded System. This post related to Embedded System Interview Questions and Answers, Embedded System Interview Questions and Answers Freshers, Embedded System Interview Questions and Answers, Embedded System Interview Questions will help you let out find all the solutions that are frequently asked in you upcoming Embedded System interview.

Over thousands of vacancies available for the Embedded System developers, experts must be acquaintance with all the component of Embedded System technologies. This is necessary for the students in order to have in-depth knowledge of the subject so that they can have best employment opportunities in the future. Knowing every little detail about Embedded System is the best approach to solve the problems linked with problem.

APTRON has spent hours and hours in researching about the Embedded System Interview Questions and Answers, Embedded System Interview Questions and Answers Freshers, Embedded System Interview Questions and Answers, Embedded System Interview Questions that you might encounter in your upcoming interview.  All these questions will alone help you to crack the interview and make you the best among all your competitors.

First of all, let us tell you about how the Embedded System technology is evolving in today’s world and how demanding it is in the upcoming years. In fact, according to one study, most of the companies and businesses have moved to the Embedded System. Now, you cannot predict how huge the future is going to be for the people experienced in the related technologies.

Hence, if you are looking for boosting up your profile and securing your future, Embedded System will help you in reaching the zenith of your career. Apart from this, you would also have a lot of opportunities as a fresher.

These questions alone are omnipotent. Read and re-read the questions and their solutions to get accustomed to what you will be asked in the interview. These Embedded System interview questions and answers will also help you on your way to mastering the skills and will take you to the giant world where worldwide and local businesses, huge or medium, are picking up the best and quality Embedded System professionals.

This ultimate list of best Embedded System interview questions will ride you through the quick knowledge of the subject and topics like C, Functions, Arrays, Storage Classes, Nested Structures, Enumerated data types. This Embedded System interview questions and answers can be your next gateway to your next job as a Embedded System expert.

These are very Basic Embedded System Interview Questions and Answers for freshers and experienced bot

Q1: Explain what is embedded system in a computer system?
A1: An embedded system is a computer system that is part of a larger system or machine.  It is a system with a dedicated function within a larger electrical or mechanical system.

Q2: Mention how I/O devices are classified for embedded system?
A2: The I/O devices of embedded system are classified into two categories

  • Serial
  • Parallel
Serial Input Output
Synchronous : Audio/Video signal Audio/Video signal
Asynchronous : Keypad, Mouse, Modem Printer, Modem
Parallel Input Output
Single bit : Rotation, Threshold sensors Pulses to external circuit
Multi bit : Vp from ADC, sensors LCD, Printer

Q3: Explain what is microcontroller?
A3: The microcontroller is a self-contained system with peripherals, memory and a processor that can be used as embedded system.

Q4: Mention what is the difference between microprocessor and microcontroller?
A4: Microprocessor is managers of the resources (I/O, memory) which lie outside of its architecture

Microcontroller have I/O, memory, etc. built into it and specifically designed for control

Q5: List out various uses of timers in embedded system?
A5: Timers in embedded system are used in multiple ways

  • Real Time Clock (RTC) for the system
  • Initiating an event after a preset time delay
  • Initiating an even after a comparison of preset times
  • Capturing the count value in timer on an event
  • Between two events finding the time interval
  • Time slicing for various tasks
  • Time division multiplexing
  • Scheduling of various tasks in RTOS

Q6: Explain what is a Watchdog Timer?
A6: A watchdog timer is an electronic device or electronic card that execute specific operation after certain time period if something goes wrong with an electronic system.

Q7: Explain what is the difference between mutexes and semaphores?

Mutexes Semaphores
  • A mutex object enables one thread into a controlled section, forcing other threads which tries to gain access to that section to wait until the first thread has moved out from that section
  • Semaphore allows multiple access to shared resources
  • Mutex can only be released by thread which had acquired it
  • A semaphore can be signaled from any other thread or process.
  • Mutex will always have a known owner
  • While for semaphore you won’t know which thread we are blocking on
  • Mutex is also a tool that is used to provide deadlock-free mutual exclusion (either consumer or producer can have the key and proceed with their work)
  • Semaphore is a synchronization tool to overcome the critical section problem
  • Mutexes by definition are binary semaphores, so there are two states locked or unlocked
  • Semaphores are usually referred to counted locks

Q8: Explain whether we can use semaphore or mutex or spinlock in interrupt context in Linux Kernel?
A8: Semaphore or Mutex cannot be used for interrupt context in Linux Kernel. While spinlocks can be used for locking in interrupt context.

Q9: What Is Difference Between Using A Macro And Inline Function?
A9: The macro are just symbolic representations and cannot contain data type differentiations within the parameters that we give. The inline functions can have the data types too defined as a part of them. The disadvantage in using both is that the inclusion of condition checks may lead to increase in code space if the function is called many times.

Q10: What Is The Volatile Keyword Used For?
A10: The volatile keyword is used to represent variables that point to memory in other mapped devices. In such a case the value of the variable can be changed outside of a program. The compiler does not do additional optimizations to the code if there is volatile keyword.

Q11: Write A Constant Time Consuming Statement Lot Finding Out If A Given Number Is A Power Of 2?
A11: If n is the given number, then the expression (n & (n-1)) = 0 gives the logical output depicting if it is a power of 2 or not, if (n & (n-1) == 0) printf (“The given number is a power of 2”);

Q12: What Is Meant By A Forward Reference In C?
A12: The forward reference refers to the case when we point an address space of a smaller data type with a pointer of a bigger data type. This can be pictured as allocating memory in single bytes and accessing it with integer pointer as chunks of 4.

Q13: What Is Isr? Can They Be Passed Any Parameter And Can They Return A Value?
A13: ISR refers to the Interrupt Service Routines. These are procedures stored at specific memory addresses which are called when certain type of interrupt occurs. The ISRs cannot return a value and they cannot be passed any parameters.

Q14: Can A Pointer Be Volatile ?
A14: Yes, although this is not very common. An example is when an interrupt service routine modifies a pointer to a buffer

Q15: What Is A ‘const’ Variable?
A15: In simple terms ‘const’ means ‘read only’. Its value is not changed by any part of the code executed. So compiler can optimize by taking this info, and also it will give warning when user try to change the value of this variable by mistake.

Q16: Explain What Happens When Recursion Functions Are Declared Inline?
A16: Inline functions property says whenever it will called, it will copy the complete definition of that function. Recursive function declared as inline creates the burden on the compilers execution. The size of the stack may/may not be overflow if the function size is big.

Q17: Explain Scope Of Static Variables?

  • Static variables can only be accessed in the files were they are declared.
  • Static variable within the scope of a function store it’s values in consecutive calls of that function.
  • Static functions can only be called within the file they are defined.

Q18: What is a pure function in ARM terminology?
A18: Pure functions are those which return a result which depends only on their arguments.

They can be thought of as mathematical functions: they always return the same result if the arguments are the same. To tell the compiler that a function is pure, use the special declaration keyword __pure.

__pure int square(int x)

{ return x * x;


Compiler does optimization for pure functions. For example, the values which are allocated to memory can be safely cached in registers, instead of being written to memory before a call and reloaded afterwards.

Q19: Which is better a char, short or int type for optimization?
A19: Where possible, it is best to avoid using char and short as local variables. For the types char and short the compiler needs to reduce the size of the local variable to 8 or 16 bits after each assignment. This is called sign-extending for signed variables and zeroextending for unsigned variables.

It is implemented by shifting the register left by 24 or 16 bits, followed by a signed or unsigned shift right by the same amount, taking two instructions (zero-extension of an unsigned char takes one instruction).

These shifts can be avoided by using int and unsigned int for local variables. This is particularly important for calculations which first load data into local variables and then process the data inside the local variables.

Even if data is input and output as 8- or 16-bit quantities, it is worth considering processing them as 32-bit quantities

Q20: Differentiate testing and verification?
A20: Verification is a front end process and testing is a post silicon process. Verification is to verify the functionality of the design during the design cycle. Testing is find manufacturing faults.

a &= ~BIT3;


Some people prefer to define a mask together with manifest constants for the set and clear values. This is also acceptable. The element that I’m looking for is the use of manifest constants, together with the |= and &= ~ constructs

Q21: Mention what are buses used for communication in embedded system?
A21: For embedded system, the buses used for communication includes

  • I2C: It is used for communication between multiple ICs
  • CAN: It is used in automobiles with centrally controlled network
  • USB: It is used for communication between CPU and devices like mouse, etc.

While ISA, EISA, PCI are standard buses for parallel communication used in PCs, computer network devices, etc.

Q22: Explain what is semaphore?
A22: A semaphore is an abstract datatype or variable that is used for controlling access, by multiple processes to a common resource in a concurrent system such as multiprogramming operating system.  Semaphores are commonly used for two purposes

  • To share a common memory space
  • To share access to files

Q23: Explain DB.
– DB is called as define byte used as a directive in the assembler.
– It is used to define the 8 bit data in binary ,hexadecimal or decimal formats.
– It is the only directive that can be used to define ASCII strings larger than two characters.
– DB is also used to allocate memory in byte sized chunks.
– The assembler always converts the numbers lnto hexadecimal.

Q24: What is EQU?
– EQU is the equate assmbler directive used to define a constant without occupying a memory location.
– It associates a constant value with data label .
– Whenever the label appears in the program ,constant value is subsituted for label.
– Advantage: The constant value occuring at various positions in a program can be changed at once using this directive.
– Syntax: label EQU constant value

Q25: Can single bit of a port be accessed in 8051?
– Yes, 8051 has the capability of accessing only single bit of a port.
– Here only single bit is accessed and rest are unaltered.
Syntax: “SETB X. Y”.
– Here X is the port number and y is the desired bit.
Example: SETB P1.2
Here the second bit of port 1 is set to 1.

Other than SETB, CLR are there any single bit instructions?

– There are total 6 single-bit instructions.
– CPL bit : complement the bit (bit= NOT bit).
– JB bit,target: Jump to target if bit equal to 1.
– JNB bit,target: Jump to target if bit is equal to 0.
– JCB bit,target: Jump to target if bit is equal to 1 and then clear bit

Embedded System Conclusion Interview FAQs

We know the list of Embedded System Interview Questions and Answers, Embedded System Interview Questions and Answers Freshers, Embedded System Interview Questions and Answers, Embedded System Interview Questions is overwhelming but the advantages of reading all the questions will maximize your potential and help you crack the interview. The surprising fact is that this Embedded System interview questions and answers post covers all the basic of the Embedded System technology and you have to check out the FAQs of different components of Embedded System too.

However, you will be asked with the questions in the interview related to the above mentioned questions. Preparing and understanding all the concept of Embedded System technology will help you strengthen the other little information around the topic.

After preparing these interview questions, we recommend you to go for a mock interview before facing the real one. You can take the help of your friend or a Embedded System expert to find the loop holes in your skills and knowledge. Moreover, this will also allow you in practicing and improving the communication skill which plays a vital role in getting placed and grabbing high salaries.

Remember, in the interview, the company or the business or you can say the examiner often checks your basic knowledge of the subject. If your basics is covered and strengthened, you can have the job of your dream. The industry experts understand that if the foundation of the student is already made up, it is easy for the company to educate the employ towards advance skills. If there are no basics, there is no meaning of having learnt the subject.

Therefore, it’s never too late to edge all the basics of any technology. If you think that you’ve not acquired the enough skills, you can join our upcoming batch of Embedded System Training in Noida. We are one of the best institute for Embedded System in noida which provide advance learning in the field of Embedded System Course. We’ve highly qualified professionals working with us and promise top quality education to the students.

We hope that you enjoyed reading Embedded System Interview Questions and Answers, Embedded System Interview Questions and Answers Freshers, Embedded System Interview Questions and Answers, Embedded System Interview Questions and all the FAQs associated with the interview. Do not forget to revise all the Embedded System interview questions and answers before going for the Embedded System interview. In addition to this, if you’ve any doubt or query associated with Embedded System, you can contact us anytime. We will be happy to help you out at our earliest convenience. At last, we wish you all the best for your upcoming interview on Embedded System Technology.