50+ Embedded Software Developer Interview Questions and Answers

There are 4 possible result cases when finding the maximum of three numbers.

• The maximum number is the same as the first number.

• The maximum number is the same as the second number.

• The maximum number is the same as the third number.

• The maximum number is different from all three numbers.

This program checks if a given number is a power of 2 using bitwise operations.

• A number is a power of 2 if it has exactly one bit set in its binary representation.

• You can use the expression (n & (n - 1)) == 0 to check this.

• Example: 4 (binary 100) is a power of 2, while 6 (binary 110) is not.

• The program should handle edge cases like 0 and negative numbers.

volatile constant and constant volatile are different in terms of read and write access.

• volatile constant means the value can be changed by external factors but cannot be modified by the program

• constant volatile means the value cannot be changed by external factors but can be modified by the program

• the order of volatile and constant keywords matter

• example: volatile const int a = 5; const volatile int *b = &a;

• a can be changed by external factors but cannot be modified by the p...read more

Short an array without using another array, with minimum parameters

• Use a sorting algorithm like bubble sort or insertion sort

• Iterate through the array and compare adjacent elements, swapping them if necessary

• Repeat the process until the array is sorted

Interfacing microprocessor kit with I/O devices involves selecting appropriate communication protocol and configuring the microprocessor pins.

• Select appropriate communication protocol (e.g. SPI, I2C, UART)

• Configure microprocessor pins for communication

• Write code to communicate with I/O devices

• Test and debug the interface

Unions in C are used to store different data types in the same memory location.

• Unions are used to save memory by allowing different data types to share the same memory location.

• They are commonly used in situations where only one of the data types needs to be accessed at a time.

• For example, a union can be used to store an integer and a float, with only one being accessed depending on the context.

A 120-ohm resistor is used in the CAN protocol to match the characteristic impedance of the network and reduce signal reflections.

• The 120-ohm resistor helps to match the characteristic impedance of the CAN network, which is typically 120 ohms.

• It reduces signal reflections that can cause data corruption and communication errors.

• The resistor is placed at both ends of the CAN bus to ensure proper termination.

• Without the resistor, the signal quality and reliability of the CAN com...read more

Validating user input for factorial calculation

• Use a loop to calculate the factorial of the number

• Check if the input is a positive integer

• Handle edge cases such as 0 and 1

• Use try-except block to catch non-integer inputs

Constructor is a special member function used for initializing objects. Virtual constructor is not possible in C++. Virtual destructor can be implemented.

• Constructor is a special member function with the same name as the class, used for initializing objects.

• Virtual constructor is not possible in C++ as constructors cannot be virtual.

• Virtual destructor is possible in C++ and is used to ensure proper cleanup of resources when an object is destroyed.

• Example: virtual ~ClassName()...read more

Friend function is a function that is not a member of a class but has access to its private and protected members. Getter setter are methods used to access and modify private variables. Static variables are shared among all instances of a class. Static functions are functions that can be called without an instance of the class.

• Friend function allows external functions to access private and protected members of a class.

• Getter setter methods are used to get and set the values o...read more

As an embedded software developer, I have experience with microcontrollers, protocols, debugging, and IDEs.

• I have worked with microcontrollers such as Arduino, STM32, and PIC.

• I am familiar with protocols such as UART, SPI, I2C, and CAN.

• For debugging, I have used tools such as JTAG, GDB, and logic analyzers.

• I have experience with IDEs such as Eclipse, Keil, and MPLAB.

• One difficult problem I faced was optimizing code for a real-time system with limited resources. I solved it by...read more

Storage classes in programming define the scope, lifetime, and visibility of variables.

• 1. Automatic: Variables are created when a block is entered and destroyed when it exits. Example: 'int a;' inside a function.

• 2. Static: Variables retain their value between function calls. Example: 'static int count = 0;' inside a function.

• 3. External: Variables are accessible across multiple files. Example: 'extern int globalVar;' declared in one file and used in another.

• 4. Register: Sugge...read more

Structures store multiple data types, while unions share the same memory space for different data types.

• Structures allocate separate memory for each member, allowing simultaneous access.

• Unions use a single memory location for all members, saving space but limiting access to one member at a time.

• Example of a structure: struct Person { char name[50]; int age; };

• Example of a union: union Data { int intValue; float floatValue; char charValue; };

The volatile keyword in programming is used to indicate that a variable's value can be changed unexpectedly.

• Used to prevent compiler optimizations that assume variable values do not change outside of the program

• Commonly used for variables that are modified by hardware or other threads

• Example: volatile int sensorValue; // variable updated by external sensor

The sub function of 19 02 is not specified.

• The question does not provide any context or information about the sub function of 19 02.

• Without additional details, it is impossible to determine the specific sub function being referred to.

• More information or clarification is needed to answer the question.

Count the number of palindromes in a given string.

• Iterate through the string and check for palindromes of length 1, 2, 3, ... n

• Use two pointers to check if a substring is a palindrome

• Consider both even and odd length palindromes

• Store the count of palindromes found

My language strength in programming is primarily in C and C++, with experience in other languages as well.

• Proficient in C and C++ programming languages

• Familiar with other languages such as Python and Java

• Experience in developing embedded software using C and C++

• Knowledge of low-level programming and hardware interfaces

• Ability to write efficient and optimized code

• Understanding of software development methodologies and best practices

LED interfacing involves connecting LEDs to a microcontroller and controlling them using software.

• Connect LED to microcontroller output pin

• Use software to set output pin high or low to turn LED on or off

• Use PWM to control LED brightness

• Use external driver circuit for high-power LEDs

• Use resistors to limit current and prevent damage to LED

Write a custom memcpy function with boundary condition handling.

• Use pointers to copy data from source to destination.

• Check for NULL pointers and zero length cases.

• Use a loop to copy data byte by byte.

• Handle overlapping memory regions with caution.

Use bitwise operations to get and set the nth bit in a number efficiently.

• To get the nth bit: Use bitwise AND with a mask. Example: (num & (1 << n)) != 0 checks if nth bit is set.

• To set the nth bit: Use bitwise OR with a mask. Example: num | (1 << n) sets the nth bit to 1.

• To clear the nth bit: Use bitwise AND with the negation of the mask. Example: num & ~(1 << n) clears the nth bit.

• To toggle the nth bit: Use bitwise XOR with a mask. Example: num ^ (1 << n) toggles the nth bi...read more

Latest embedded C programming includes features like dynamic memory allocation, multi-threading, and object-oriented programming.

• Dynamic memory allocation allows for more efficient use of memory

• Multi-threading enables concurrent execution of multiple tasks

• Object-oriented programming allows for better code organization and reusability

SPI is faster, full-duplex, and uses separate data lines, while I2C is slower, half-duplex, and uses a shared data line.

• SPI is faster than I2C

• SPI is full-duplex, allowing data to be sent and received simultaneously

• SPI uses separate data lines for communication

• I2C is slower than SPI

• I2C is half-duplex, meaning data can only be sent or received at a time

• I2C uses a shared data line for communication

Structured, pointer, array, and union are all data types in C programming language.

• Structured data type is a collection of variables of different data types under a single name.

• Pointer is a variable that stores the memory address of another variable.

• Array is a collection of similar data types stored in contiguous memory locations.

• Union is a special data type that allows storing different data types in the same memory location.

• Example: struct employee { char name[20]; int age;...read more

Find intersection point of two linked lists and optimize solution.

• Traverse both lists and find their lengths

• Move the head of the longer list to the same distance as the shorter list

• Traverse both lists in parallel until they meet at the intersection point

• Use hash table to store visited nodes for faster lookup

• Use two pointers, one starting from the head of each list, and move them at the same pace until they meet at the intersection point

Code for bit set or reset

• To set a bit, use bitwise OR operator with 1 shifted left by the bit position

• To reset a bit, use bitwise AND operator with the complement of 1 shifted left by the bit position

• Use unsigned integer data type for bit manipulation

Static libraries are linked at compile-time, while dynamic libraries are linked at run-time.

• Static libraries are included in the final executable file, increasing its size.

• Dynamic libraries are loaded into memory only when needed, reducing the executable size.

• Static libraries are platform-specific, while dynamic libraries can be shared across platforms.

• Static libraries provide faster execution, while dynamic libraries allow for easier updates and maintenance.

• Examples of stati...read more

Networks are essential for communication and data transfer between devices and systems.

• Networks enable devices to communicate and share data with each other.

• They allow for remote access and control of devices.

• Networks facilitate the transfer of large amounts of data quickly and efficiently.

• They enable the creation of complex systems and applications that rely on multiple devices and components.

• Examples include the internet, local area networks (LANs), and wireless networks.