In this article, we have listed Interview Questions and Answers for Embedded Engineer Job opportunities. These Embedded Engineer Interview Question Answers are divided into various categories which will help you crack Interviews and secure your job. All the categories and questions are listed below, click and explore the l/topic -
Interview Questions for Embedded Engineer Categories:
Basic Concepts:
Q1: What is an embedded system?
Answer: An embedded system is a dedicated computer system designed to perform a specific function or set of functions, often within a larger system. Examples include microcontrollers in washing machines, thermostats, and automotive control systems.
Q2: What are the main components of an embedded system?
Answer:
Microcontroller/Microprocessor: The brain of the system.
Memory: Includes RAM, ROM, and Flash for data storage.
Sensors and Actuators: For interaction with the environment.
Communication Interfaces: Like UART, SPI, I2C, and CAN for data exchange.
Power Supply: Provides necessary voltage and current to the components.
Q3: What is the difference between a microcontroller and a microprocessor?
Answer:
A microcontroller is a self-contained system with a processor, memory, and peripherals in one chip.
A microprocessor is just a CPU and requires external peripherals like memory and input/output devices to function.
Q4: Why is C preferred for embedded systems?
Answer:
It provides low-level access to hardware.
It is memory-efficient and faster than high-level languages.
Its portability and availability of compilers make it ideal for embedded development.
Q5: What is a volatile keyword in C? Why is it used?
Answer:
Volatile tells the compiler not to optimize the variable because its value can change unexpectedly, such as with hardware registers or interrupts.
Example:volatile int flag;
Q6: Explain the difference between const and #define.
Q7: What is the use of a watchdog timer?
Answer: A watchdog timer resets the system if it detects the software has stopped functioning properly, ensuring the system recovers from failures.
Q8: What is an RTOS, and why is it used?
Answer: An RTOS is an operating system designed for real-time applications where tasks must meet strict timing constraints. It is used for task scheduling, resource management, and improving system reliability.
Q9: What are the states of a task in RTOS?
Answer:
Ready: Task is ready to run.
Running: Task is currently being executed.
Blocked: Task is waiting for an event or resource.
Suspended: Task is inactive and not eligible for scheduling.
Q10: What is priority inversion?
Answer: Priority inversion occurs when a high-priority task is waiting on a resource held by a lower-priority task, and the lower-priority task cannot proceed due to interference from medium-priority tasks.
Q11: How does UART communication work?
Answer: UART (Universal Asynchronous Receiver Transmitter) is a serial communication protocol that uses two lines: TX (transmit) and RX (receive). It sends data byte by byte asynchronously, using start/stop bits for synchronization.
Q12: What is the difference between I2C and SPI?
Answer:
I2C: Uses two wires (SDA, SCL), supports multiple masters/slaves, slower, but simpler.
SPI: Uses four wires (MOSI, MISO, SCLK, SS), faster, but requires more connections.
Q13: What is the purpose of an interrupt?
Answer: Interrupts are hardware or software signals that temporarily halt the CPU’s current task to execute a higher-priority routine, like responding to an external event.
Q14: Explain the difference between polling and interrupt.
Answer:
Polling: CPU continuously checks for a condition or event.
Interrupt: CPU is notified only when an event occurs, making it more efficient.
Q15: How do you debug an embedded system?
Answer:
Use tools like JTAG, SWD, or In-Circuit Debuggers.
Use serial communication (UART/printf) for debugging logs.
Analyze memory dumps and use oscilloscopes or logic analyzers.
Debug with breakpoints and watch variables in IDEs.
Q16: What steps would you take to optimize embedded code?
Answer:
Minimize memory usage.
Use inline functions for frequently called small functions.
Avoid dynamic memory allocation where possible.
Optimize loops and algorithms.
Utilize compiler optimization flags.
Q17: What is DMA, and why is it used?
Answer: DMA (Direct Memory Access) allows peripherals to transfer data to/from memory without CPU involvement, improving system efficiency by freeing up the CPU.
Q18: What is endianness, and why does it matter in embedded systems?
Answer: Endianness refers to the byte order used to store multi-byte data.
Big Endian: Most significant byte is stored first.
Little Endian: Least significant byte is stored first.It is important to ensure compatibility between devices with different architectures.
Q19: How would you reduce power consumption in an embedded system?
Answer:
Use low-power modes of microcontrollers.
Optimize clock speeds.
Power down unused peripherals.
Use efficient algorithms to reduce processing time.
Q20: What is memory-mapped I/O?
Answer: Memory-mapped I/O assigns hardware registers to specific memory addresses, allowing them to be accessed using standard read/write instructions.
Q21: What are the roles of an Embedded Systems Engineer?
Answer: Role: Develop hardware and software for embedded systems, such as microcontrollers, IoT devices, and automotive systems.
Q22: What are the required skills for an Embedded Systems Engineer?
Answer: Skills: C/C++, Embedded C, RTOS, microcontrollers, and ARM architecture.
Q23: What type of Industries use an Embedded Systems Engineer?
Answer: Industries: Automotive, healthcare, IoT, consumer electronics.
Few more important Interview Questions and Answers:
1. What is the startup code?
Answer: It is a code that is called before the execution of the main function. It creates a platform for an application to run. It is called an assembly language.
2. What is the Semaphore?
Answer: It is a variable that is non-negative and can be shared between threads. It solves the critical selection problem and achieves synchronization in the processes.
3. What are the 2 types of Semaphore?
Answer: The 2 semaphores are Binary Semaphore and Counting Semaphore.
4. What is the full form of ISR?
Answer: ISR means Interrupt Service Routines. It is used when an interruption occurs. These procedures are stored at a memory location in the software.
5. When do we use a volatile keyword?
Answer: When a compiler changes its behavior unexpectedly after optimization, a volatile keyword is used.
6. What are the advantages of an Embedded system?
Answer: Some advantages of embedded systems are
It is reliable
It is inexpensive and small in size
It ensures mass production
Its operations are fast and require low power
It improves product quality
7. What are the disadvantages of Embedded Systems?
Answer:
It is hard to maintain because of its use and throw nature
It does not improve the technology
It uses less power if it is battery operated
Backup of embedded files is hard to take
8. What is an embedded system?
Answer: It is a hardware system that software designed to perform a specific specialized function or task. It can be a complete system or belong to a large system.
9. List the components of an embedded system.
Answer: There are 3 components of an embedded system
Hardware
Software
Operating system
These components are further divided into
Processor
Memory
Timers counters
Communication ports
Output
Input
10. State the difference between thread and process.
Answer: A process is a program under execution running in separate memory spaces, whereas a thread is a segment of a process that shares information with other threads while containing its registers, counters, etc.
11. What is interrupt latency?
Answer: It is the time taken by ISR to respond to an interruption. Less latency means a faster response to the interrupting event.
12. When does a segmentation fault occur?
Answer: When a program instruction tries to access the prohibited memory address, a segmentation fault occurs. It sometimes leads to crashes in the programs.
13. Can a variable be volatile and const both?
Answer: Yes. Const keyword is used when a variable’s value should not change. But interrupts can still change the value.
14. What is a RISC architecture?
Answer: RISC architecture means Reduced instruction set computer architecture. It is a type of microprocessor architecture utilizing a small and highly optimized set of instructions to compute tasks in the least amount of time.
15. What is a reentrant function?
Answer: When a function can be interrupted during execution and can be called again safely, it is a reentrant function. The function resumes from the same point where it was left.
16. Which loop is better?
Answer: Countdown to zero loop is better than count up loops. This ensures the optimization of comparison to zero during loop termination.
17. What is the watchdog timer?
Answer: It is a part of the hardware that detects malfunctioning or anomalies in the software of the computer. It prevents the system from dangerous situations by detecting the faults in advance.
18. What is a Null pointer?
Answer: A Null pointer does not point to any valid memory location. It ensures that no pointer should be used to modify as it is invalid. It is addressed as NULL.
19. What is the syntax for a null pointer?
Answer: Data_type *pointer_name = NULL;
20. What does “const int x;” mean?
Answer: It means the variable is a read-only constant integer.
21. Which statement is faster ++I or i+1?
Answer: ++i is faster because it uses single machine instruction, but i+1 requires loading.
22. How can the errors in segmentation fault be avoided?
Answer: The Errors can be avoided in the following ways
Initializing pointer properly
Minimizing the use of pointers
Troubleshooting
23. Can printf() be used inside ISR?
Answer: No, it cannot be used in ISR because printf() is a non-reentrant and thread-safe function.
24. Can we pass or return a value or a parameter to ISR?
Answer: This is not possible because ISR does not allow anything to pass or return from it.
25. Why does interrupt latency happen?
Answer: It happens because
The signal synchronization with the CPU depends on the hardware of the processor. It can take up to 3 CPU cycles for a signal to reach the processor.
After the execution of an instruction, it takes some extra CPU cycles to refill the pipeline again with the instructions. This leads to latency.
26. How can you reduce interrupt latency?
Answer: Interrupt latency can be reduced by shortening the ISR routines.
27. How can you avoid a character pointer from pointing to a different address?
Answer: Since constant protects a pointer from modifications, The pointer should be defined as a constant character pointer.
28. What is a memory leak?
Answer: When the developers create objects or use the memory to help memory and then forget to free it before completing the program, a memory leak occurs. This leads to reduced memory availability and often crashes of the application.
29. What are the errors in an Embedded System?
Answer: Some common errors are
Data connection malfunctioning
Address line malfunctioning
Inaccessible memory location
Faulty control signals
Faults in memory devices
30. How can you avoid a memory leak?
Answer: A Memory leak can be avoided by freeing the objects or pointers when no longer in use.
31. List some live examples of embedded systems use.
Answer: Embedded Systems are widely used in
Identifying the speed of vehicles on a highway and intimating the authorities.
Finding the accurate location of a vehicle by using GPS.
The Automation system in houses with the help of android-operated remotes.
32. Explain a Microcontroller.
Answer:A Microcontroller also called an embedded controller, is a system inserted in a device to control the functioning of a product.
33. How can you swap 2 variables?
Answer: 2 variables can be swapped in the following ways
Using extra memory space
Using arithmetic operators
Using Bitwise operators
Using One-Liner Bitwise operators
Using One-Liner Arithmetic operators
34. Explain Automotive Embedded System.
Answer: Automotive Embedded System is a computer system designed for electronic devices that controls the mechanism of data and devices.
35. What is an Embedded C?
Answer: Embedded C is a part of the C programming language. It develops applications that are based on microcontrollers like Cameras, WiFi, etc.
36. List the 4 levels of testing in Embedded Systems.
Answer: The 4 levels of testing are
Unit testing
Integration testing
System testing
User acceptance testing
37. What are the different types of Buses used by Embedded Systems?
Answer:
Memory Bus: It is related to the memory-connected processor.
Multiplexed Bus:It reads and writes in memory.
De-multiplexed Bus:It contains 2 wires in the same bus. One has the address, and the other contains the data.
Input/Output Bus:It multiplexes the same input and output signals by using multiplexing techniques.
38. What are the 5 characteristics of Embedded Systems?
Answer: Characteristics of Embedded Systems
Sole Functioning
It usually performs a single specialized function repeatedly.
Constraints
All computing systems on Embedded Systems have tight constraints.
Real-Time
The embedded systems react to the system’s environment changes And bring quick results.
Memory
Since the software is embedded in ROM, it has a memory and does not need any other secondary memory in the computer.
Processor
It must be based on a microprocessor or a microcontroller.
39. What are the types of Embedded Systems?
Answer: Embedded systems are classified on 2 factors
1. Based on performance and functional requirements
It is further divided into 4 types
Real-time embedded systems
Standalone embedded systems
Networked embedded systems
Mobile embedded systems
40. Based on the performance of microcontrollers
It is divided into 3 types
Small-scale embedded systems
Medium-scale embedded systems
Complex embedded systems
41. Which software is used for Embedded Systems?
Answer: In most cases, embedded systems use basic embedded system software like C, C++, ADA, etc. The Specialized systems use operating systems such as Windows CE, LINUX, TreadX, Nucleus RTOS, OSE, etc.
44. What are Embedded Tools?
Answer:
Text editor
Compiler
Assembler
Debugger
Linker
Emulator
Integrated development environment (A software that provides necessary tools in a single package)
Conclusion:
Hope these embedded systems interview questions and answers will help you answer your interviews confidently and with better preparedness.
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