20+ Embedded Firmware Engineer Interview Questions and Answers

Components involved in the internal logic circuit of a 7-segment display include decoder, driver, and individual LED segments.

• Decoder: Converts input signals into the appropriate output signals for each segment.

• Driver: Amplifies the output signals from the decoder to drive the LED segments.

• Individual LED segments: Represent each of the seven segments in the display.

• Example: BCD to 7-segment decoder, transistor driver circuit, LED segments.

The trains will meet at a point that is determined by the relative speeds of the trains.

• The point where the trains meet is determined by the sum of the distances traveled by each train.

• The time taken for the trains to meet is determined by the relative speeds of the trains.

• If Train A is traveling at 50 mph and Train B is traveling at 70 mph, they will meet at a point that is closer to Train B's starting point.

Design a vending machine using a microcontroller with two 7-segment displays and additional operational conditions.

• Use a microcontroller to control the vending machine's operations

• Incorporate two 7-segment displays to show the amounts

• Include four to five additional operational conditions such as low inventory alert, coin validation, product selection, etc.

Assembly language program to reverse a byte for a hexadecimal value.

• Load the hexadecimal value into a register

• Extract the lower 4 bits and upper 4 bits of the byte

• Swap the lower and upper 4 bits

• Combine the swapped bits to get the reversed byte

Education can help individuals earn money by providing them with valuable skills, knowledge, and opportunities for career advancement.

• Education can lead to higher paying job opportunities

• Specialized education or training can result in higher salaries

• Education can also lead to promotions and career advancement

• Higher levels of education are often correlated with higher earning potential

Life is a journey filled with experiences, challenges, growth, and opportunities for self-discovery.

• Life is a precious gift that should be cherished and lived to the fullest

• It involves constant learning, adapting, and evolving as individuals

• Life is about forming meaningful relationships and connections with others

• It includes pursuing passions, setting goals, and overcoming obstacles

• Life is a balance of joy and sorrow, success and failure, love and loss

Parameters responsible for program crash

• Null pointers

• Memory leaks

• Stack overflow

• Infinite loops

• Invalid input

• Hardware failure

Yocto is used to create custom Linux distributions tailored for specific embedded systems, providing flexibility and efficiency.

• Yocto allows for customization of Linux distributions for specific hardware requirements

• Enables easy integration of custom software components and drivers

• Provides a streamlined and efficient build process for embedded systems

• Offers a consistent and reproducible development environment

• Facilitates maintenance and updates for embedded devices

Structures store multiple variables of different types, while unions store multiple variables but share the same memory space.

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

• Unions use a single memory location for all members, meaning only one member can be accessed at a time.

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

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

• Size of a structure is t...read more

Hexadecimal to decimal conversion involves multiplying each digit by 16 raised to the power of its position.

• Start from the rightmost digit and multiply each digit by 16 raised to the power of its position (0-indexed).

• Add the results of each multiplication to get the decimal equivalent.

• For example, converting 0x1A to decimal: (1 * 16^1) + (10 * 16^0) = 26.

Design a digital circuit to control car tail lights based on specifications

• Use microcontroller to receive input signals from car's sensors

• Implement logic to determine when to turn on/off tail lights (e.g. based on brake pedal or light sensor)

• Connect output of microcontroller to control the tail lights

Program to calculate minimum number of notes for ATM withdrawal

• Create an array of available note denominations

• Sort the array in descending order

• Initialize a counter variable to keep track of the number of notes

• Iterate through the array and divide the withdrawal amount by each note denomination

• Update the counter variable with the quotient

• Update the withdrawal amount with the remainder

• Repeat the above steps until the withdrawal amount becomes zero

• Return the counter variable as ...read more

Digital filters can be implemented through software by using algorithms such as Finite Impulse Response (FIR) or Infinite Impulse Response (IIR).

• Choose the appropriate filter type based on the desired frequency response and computational complexity

• Implement the filter algorithm in the firmware code using programming languages like C or assembly

• Optimize the filter design for efficient memory usage and processing speed

• Test the filter implementation using simulation tools or har...read more

SIL (Safety Integrity Level) is required after MIL (Military) to ensure that safety-critical systems meet specific safety requirements.

• SIL is a measure of the reliability of a system in performing a safety function.

• It is used in industries such as automotive, aerospace, and medical devices to ensure safety.

• MIL standards focus on military requirements, while SIL standards focus on safety requirements.

• For example, in medical devices, SIL levels are used to ensure the safety and...read more

Volatile keyword is used to indicate that a variable's value can be changed unexpectedly.

• It is used in embedded systems where hardware can change a variable's value

• It tells the compiler not to optimize the variable

• It ensures that the variable is always read from memory and not from a cache

• Example: a variable that is updated by an interrupt service routine

Yes, an array can be passed to a function in embedded firmware programming.

• Arrays can be passed to functions by specifying the array name as the argument.

• The function can then access and manipulate the elements of the array.

• Example: void printArray(int arr[], int size) { ... }

• Example: int main() { int myArray[] = {1, 2, 3}; printArray(myArray, 3); }

Function pointer syntax allows for storing the address of a function in a pointer variable.

• Syntax: return_type (*pointer_name)(parameters)

• Example: void (*funcPtr)(int) = &someFunction;

A communication protocol is a set of rules that defines how data is transmitted and received over a network.

• Protocols ensure reliable data exchange between devices.

• Examples include TCP/IP for internet communication and I2C for short-distance communication between chips.

• Protocols can be categorized as connection-oriented (e.g., TCP) or connectionless (e.g., UDP).

• They define aspects like data format, timing, and error handling.

Find the minimum number of swaps needed to sort an array

• Iterate through the array and count the number of swaps needed to sort it

• Use a sorting algorithm like bubble sort or selection sort to determine the minimum swaps

• Track the indices of the elements in the original array to calculate the swaps needed

Learn how to set, clear, and toggle bits in embedded systems using bitwise operations.

• Setting a bit: Use bitwise OR. Example: `value |= (1 << bit_position);`

• Clearing a bit: Use bitwise AND with NOT. Example: `value &= ~(1 << bit_position);`

• Toggling a bit: Use bitwise XOR. Example: `value ^= (1 << bit_position);`

• Bit positions are zero-indexed, starting from the least significant bit.

Compilation process in C involves preprocessing, compiling, assembling, and linking.

• Preprocessing: Includes header files, macro expansions, and conditional compilation.

• Compiling: Translates source code to assembly code specific to the target architecture.

• Assembling: Converts assembly code to machine code in object files.

• Linking: Combines object files and libraries to generate an executable file.

Developed firmware for a smart home automation system

• Designed and implemented communication protocols for various IoT devices

• Developed low-level drivers for sensors and actuators

• Optimized power consumption for battery-operated devices

• Integrated with cloud services for remote monitoring and control

SR flip flop is a latch with two inputs (Set and Reset) while D flip flop has a single input (Data).

• SR flip flop has two inputs - Set and Reset, and can be used to store one bit of data.

• D flip flop has a single input - Data, and is used to store one bit of data as well.

• SR flip flop can have both inputs high, which is an invalid state, while D flip flop always has a valid input state.

• D flip flop is edge-triggered, meaning it only changes state on the rising or falling edge of ...read more

Reverse a given string

• Use a loop to iterate through the characters of the string

• Swap the characters from start to end of the string

• Continue swapping until reaching the middle of the string

Embedded C is a programming language used for developing software for embedded systems.

• Embedded C is a subset of the C programming language.

• It is optimized for resource-constrained systems with limited memory and processing power.

• It allows direct access to hardware and provides low-level control.

• Embedded C is used in various industries like automotive, aerospace, consumer electronics, etc.

• Example: Writing code to control a microcontroller or designing a real-time operating sy...read more