Embedded Prep

Welcome to our comprehensive blog on Embedded C Interview Questions, your one-stop resource to prepare for embedded systems interviews with confidence. Whether you’re a beginner looking to break into embedded development or an experienced engineer brushing up on key concepts, this blog offers a curated list of frequently asked interview questions and expert answers.

Explore a wide range of topics including memory management, pointers, data structures, bitwise operations, interrupts, real-time operating systems (RTOS), and microcontroller programming. Each question is explained in a clear, beginner-friendly manner with practical code examples and real-world relevance.

Perfect for students, job seekers, and professionals, this blog helps you build a solid foundation in Embedded C and crack interviews at companies like Bosch, Qualcomm, STMicroelectronics, NXP, and more.

Stay ahead in your career—start mastering Embedded C today!

Basic Embedded C Interview Questions

• What is Embedded C Programming? How is Embedded C different from C
  language?
• What are the different data types in Embedded C?
• What is the role of main() in Embedded C programs?
• What is Void Pointer in Embedded C and why is it used?
• Why do we use the volatile keyword?
• What are the differences between the const and volatile qualifiers in embedded
  C?
• What are preprocessor directives? Name a few.
• What Is Concatenation Operator in Embedded C?
• How will you use a variable defined in source file1 inside source file2?
• What are the differences between Inline and Macro Function?
• Is it possible for a variable to be both volatile and const?
• Is it possible to declare a static variable in a header file?
• What do you understand by the pre-decrement and post-decrement operators?
• What is a reentrant function?
• What kind of loop is better – Count up from zero or Count Down to zero?
• What do you understand by a null pointer in Embedded C?
• Why is the statement ++i faster than i+1?
• Is it possible to protect a character pointer from accidentally pointing it to a different address?
• What do you understand by Wild Pointer? How is it different from Dangling Pointer?
• What are the differences between the following 2 statements #include “…” and #include <…>?
• Difference between while(1) and while(0) in C language?
• Describe the role of the “typedef” keyword in embedded C.
• Difference Between Structure and Array in C?
• Difference Between Structure and Union in C?
• Explain What Are The Different Storage Classes In C?
• Explain What Are The Different Qualifiers In C?
• What Is Pass By Value And Pass By Reference?
• What are the uses of the Keyword Static?
• What does “const int x;” mean?
• Where are constant variables stored in memory?
• How can you protect a character pointer by some accidental modification with the pointer address?
• What is the keyword “volatile” used for in embedded C?
• Can a variable be volatile and const both?
• What is a Null pointer?
• What is the size of a pointer?
• What is the difference between little-endian and big-endian byte ordering
• Explain the difference between static and dynamic memory allocation in embedded C.
• How do you perform bitwise operations in embedded C?
• What is the significance of the “restrict” keyword in embedded C?
• Explain the concept of bit fields in embedded C.
• What is a union and how is it used in embedded C?
• Explain the concept of portability in embedded C programming.
• How do you implement a finite state machine in embedded C?
• Describe the process of handling errors in embedded C programming.
• How do you perform input/output operations in embedded C?
• What is the purpose of the “inline” keyword in embedded C?
• How do you handle multi-threading in embedded C?
• How do you handle endianness issues in embedded C?
• Describe the process of implementing a software stack in embedded C.
• How do you debug embedded C code?
• How do you handle floating-point arithmetic in embedded C?
• What is a pointer-to-function in embedded C?
• How do you perform code optimization in embedded C?

Intermediate Embedded C Interview Questions

1. What are memory-mapped I/O and how is it implemented in Embedded C?
2. How can you implement circular buffer (ring buffer) in Embedded C?
3. What is ISR (Interrupt Service Routine) and how do you write one in C?
4. How do you share data between main code and ISR safely?
5. What are the race conditions in Embedded C and how do you avoid them?
6. Explain how stack overflow can occur in embedded systems and how to prevent it.
7. What is memory leak and how can it happen in embedded firmware?
8. How do you perform memory alignment in Embedded C?
9. How would you use __attribute__((section(".name"))) in Embedded C?
10. What is the difference between using a union and casting in accessing hardware registers?
11. How would you implement delay without using delay() function or timers?
12. How do you prevent compiler optimization for a specific variable or function?
13. What is zero initialization and when does it occur in Embedded C?
14. What is the difference between memcpy() and memmove()?
15. How do you ensure atomicity of operations in Embedded C?
16. What is tail recursion? Is it helpful in embedded development?
17. How does compiler optimization affect Embedded C behavior?
18. What is aliasing in Embedded C and how can it lead to undefined behavior?
19. How do you prevent structure padding and packing issues?
20. What is bus contention and how can software reduce its occurrence?

Advanced Embedded C Interview Questions

1. How do you implement RTOS-level features like task switching using C?
2. How does the compiler manage interrupt vector tables in Embedded C?
3. How can function pointers be used to implement polymorphism in Embedded C?
4. How do you create bootloader code in Embedded C?
5. What is position-independent code and how do you write it in Embedded C?
6. Explain memory sections (.text, .data, .bss) and how they are used in linker scripts.
7. How can Embedded C be used to interface with DMA (Direct Memory Access)?
8. How do you implement memory pools or custom allocators in Embedded C?
9. How do you perform low-power optimization in firmware (C-level techniques)?
10. How do you handle memory-mapped peripherals in systems with shared buses?
11. What is undefined behavior in C, and how does it manifest in embedded systems?
12. How does the volatile keyword behave with pointers to structures?
13. How would you debug stack corruption or heap fragmentation in embedded systems?
14. What techniques do you use to profile and measure code performance in embedded systems?
15. How would you implement a watchdog timer service in C?
16. How can inline assembly be used in Embedded C?
17. How do you ensure MISRA C compliance in large codebases?
18. How do you implement lock-free programming techniques in Embedded C?
19. How do you use linker script to map specific variables/functions to specific addresses?
20. How do you implement a software-based CRC algorithm in C?
21. How do you handle large memory access (above 64 KB) in 16-bit microcontrollers?
22. How do you implement double buffering in Embedded C for smooth data acquisition?
23. How do you write unit tests for Embedded C code without hardware?
24. How do you manage firmware upgrades (FOTA) in embedded C systems?
25. What are trampolines in embedded programming and when are they used?

Programming Questions – Embedded C Interview Questions 2025

Basic Level Programming

1. Write a C program to toggle an LED connected to a GPIO pin every 1 second using delay loops.
2. Write a function to reverse an array of integers in place.
3. Implement a function to check if a given number is a power of two using bitwise operations.
4. Write a C program to count the number of 1s in an 8-bit integer.
5. Write a function to implement your own strlen() function.
6. Write a program to swap two variables without using a temporary variable.
7. Write a program to implement a simple circular buffer with fixed size.
8. Implement a debounce algorithm in C for a push-button input.

Intermediate Level Programming

9. Write a program to implement a software delay function using timers (assume STM32/AVR-like architecture).
10. Write an ISR (Interrupt Service Routine) to handle external interrupt on a GPIO pin.
11. Implement a state machine to control an LED that turns on/off with a button press and blinks when held.
12. Implement a memory copy function similar to memcpy() and ensure it handles overlapping memory regions.
13. Create a struct-based system to store and manage sensor readings with timestamp support.
14. Write a function that takes a pointer to a function and executes a list of callback functions.
15. Create a firmware-like program to blink 3 LEDs in sequence using only one timer.
16. Write a program to transmit a string via UART using polling (non-interrupt method).

Advanced Level Programming

17. Implement a finite state machine (FSM) in C to manage a simple traffic light system.
18. Simulate a watchdog timer that resets a system if a task fails to report within a certain time window.
19. Write code to allocate memory from a fixed-size memory pool (custom allocator).
20. Implement a CRC-8 or CRC-16 checksum algorithm in C.
21. Write embedded-safe code to compute the average of N ADC values with integer arithmetic only.
22. Implement an event queue system in Embedded C with event handlers and a dispatcher.
23. Write a bootloader stub that checks for a firmware update signature and jumps to the main application.
24. Implement I²C read/write operations with software bit-banging in C.
25. Write a code to simulate a multi-task scheduler (round-robin) in pure Embedded C.

You can also Visit other tutorials of Embedded Prep 

• Master How to Use a Saleae Logic Analyzer with Arduino Uno (2025)
• Top 30+ I2C Interview Questions
• Bit Manipulation Interview Questions
• Structure and Union in c
•  Fault Handling in Arm Cortex Mx Processor
• Merge sort algorithm

Special thanks to @mr-raj for contributing to this article on EmbeddedPrep