Landing an embedded system engineer role is no easy feat. Competition is fierce for these highly technical positions that require a rare blend of hardware, software, and engineering skills. As an aspiring embedded system engineer you need to come prepared to showcase your specialized expertise during the interview process.
In this comprehensive guide, we’ll explore some of the most commonly asked interview questions for embedded system engineering positions Whether you’re fresh out of college or a seasoned professional, these sample questions and answers will help you get ready to put your best foot forward and ace that upcoming interview.
Why Embedded Systems?
Let’s start from the beginning – interviewers often want to know what drew you to this highly specialized field in the first place. When answering, be specific about why you were attracted to the niche nature of embedded systems and how it aligns with your interests, skills, and professional goals.
For example: “I’ve always been fascinated by the intersection of hardware and software optimization in real-time embedded devices. I enjoy the challenge of designing resource-constrained systems and the reward of seeing my solutions applied in everyday products. Embedded systems allow me to blend my software programming and electrical engineering knowledge in impactful ways.”
Core Concepts
Having a rock-solid grasp of embedded systems fundamentals is a must. Expect questions that assess your knowledge of key concepts like:
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Microcontrollers: Be ready to talk about why microcontrollers are so important in embedded systems. What are their key components? How do they differ from microprocessors?.
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Real-time operating systems (RTOS) – What specific benefits do RTOS provide compared to general-purpose OS? Give examples of how multithreading and task scheduling improve performance.
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Memory management – Discuss code optimization approaches like dynamic memory allocation to maximize limited system memory.
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Interrupts—Explain what interrupts are, why they’re important in embedded systems, and the main steps in how to handle them.
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Communication protocols – Elaborate on your hands-on experience with I2C, SPI, UART, CAN bus for device communication.
Programming Proficiency
As an embedded programmer, fluency in languages like C and C++ is non-negotiable. Interviewers will probe your expertise here.
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Walk through your experience applying C/C++ efficiently in resource-constrained embedded environments.
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Highlight techniques like bit manipulation, dynamic memory allocation, and dual mode ISRs that show your technical acumen.
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For bonus points, mention any experience with other relevant languages like Python, Java, Assembly, Verilog, or VHDL.
Problem-Solving Ability
Real-world engineering challenges require creative problem-solving skills. Be ready with examples that demonstrate how you:
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Optimized performance of an embedded system – e.g. improving response time of a motion sensor system.
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Handled debugging complicated bugs – e.g. resolving stability issues in an embedded control system.
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Worked successfully within tight project constraints – e.g. designing with limited processor speed, memory, or power.
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Ensured reliability and safety – e.g. implementing redundancy, fail-safes, and other fault tolerance mechanisms.
Highlight your technical skills while also conveying your methodical and persistent approach.
Communication Ability
Collaboration is vital for embedded engineers. Expect questions about your ability to:
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Convey technical concepts clearly – e.g. through documentation, diagrams, code comments.
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Interface cross-functionally – e.g. working with software, QA, and electrical engineering teams.
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Understand client requirements – e.g. translating needs into technical specs.
Leadership Potential
For senior roles, leadership skills are highly valued. Share examples that highlight your abilities to:
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Lead projects end-to-end – e.g. from concept to launch.
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Mentor junior engineers – e.g. through code reviews, design walkthroughs.
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Drive process improvements on teams – e.g. implementing best practices.
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See the bigger picture beyond the technical – e.g. how your work impacts customers and business outcomes.
Domain Knowledge
While embedded systems span industries, specific domain expertise is prized. Showcase your specialized knowledge such as:
Automotive – CAN bus, electronic control units, ABS, advanced driver assistance systems.
Aerospace – Avionics, flight control systems, engine control units, fault-tolerant design.
Industrial – PLCs, SCADA, process control, plant floor automation.
Consumer Electronics – IoT, home automation, wearables, low power optimization.
Medical – Implants, monitors, infusion pumps, regulatory compliance.
Telecommunications – VOIP, wireless networking, real-time signal processing.
Tailor your responses to align with the company’s focus area. Demonstrating niche skills can give you a leg up.
Future Outlook
Finally, interviewers want to understand your career aspirations and continued learning focus. Show you’re staying up-to-date on embedded systems advancements like:
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Growing role of AI/machine learning in edge devices.
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Adoption of new communication protocols like 5G and Wi-Fi 6.
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Increasing security vulnerabilities requiring robust IoT protections.
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Expanding use of FPGAs for performance gains.
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Miniaturization and efficiency improvements with new fabrication processes.
Convey your motivation to keep mastering the latest embedded technologies and leveraging them to develop cutting-edge system designs.
Getting hired as an embedded system engineer takes substantial preparation. This overview of typical interview questions provides a blueprint to get you ready. Of course, expect the specific questions to vary across companies and roles. The key is having in-depth knowledge of embedded systems fundamentals, conveying your technical expertise, and demonstrating your passion and eagerness to take on new challenges. With diligent practice using these sample questions, you’ll be equipped to impress hiring managers and get the job you want!
Toptal sourced essential questions that the best embedded software engineers can answer. Driven from our community, we encourage experts to submit questions and offer feedback.
Describe the pros and cons of using a generic real-time operating system (RTOS) on a mid-range microcontroller.
RTOSes can significantly ease the development of complex products, which can translate into faster development cycles. A lot of the time, they let you separate code into tasks and set up ways for tasks to talk to each other. They also usually come with “drivers” that make it easier to port firmware to new hardware. In addition to all of that, they add extra code and CPU use, which is not good for all projects. 2 .
What are some common issues when handling interrupts?
Depending on the device and application, interrupt handlers almost always need to finish their work quickly. This makes it harder for them to do complex things in their code. Also, the hardware or software environment in which the interrupt handler code is run may make it impossible for the interrupt handler code to use:
- Common library functions
- Access to peripherals and devices
- Even certain types of CPU instructions
Most of the time, this problem can be fixed by having the interrupt controller set a special variable that non-interrupt code can then use to do whatever it wants 3
In platforms with significant constraints on memory size, is it more preferable to allocate memory statically or dynamically?
It’s preferable to use static memory allocation on platforms with memory sizes in the low kilobytes and below. This is because data overhead, CPU overhead, and memory fragmentation can be big problems when dynamic memory allocation is used.
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Why are C and C++ still very popular and widely supported in embedded firmware development?
Hardware constraints, both for memory sizes and CPU speed, limit what can be done on embedded devices. When it comes to abstractions, C and C usually have very little overhead and are very “close to the hardware.” This makes them suitable for even the smallest devices. 5 .
How many wires are required to reliably implement TTL-like serial communication between two devices, and why?
Serial communication that works like TTL is often used to connect small microcontroller-based devices to bigger computers, either for general communication or to upload firmware. This type of communication uses two wires, one for each direction, called TX (transmit) and RX (receive. For TTL serial communication to work, there must also be a shared electrical ground level between the devices. This means that at least three wires are needed. (The requirement for common electrical ground is also present in I2C and SPI. ) 6 .
Since 32-bit and 64-bit microcontrollers exist, why are 8-bit ones still in use?
The general reason is picking the right tool for the job. The three most common reasons are backwards compatibility, price, and electrical power consumption. Backwards compatibility is important when connecting to systems that are already in place. This is especially true in industrial settings, where electrical and operational limitations often limit the microcontrollers that can be used.
Generally, smaller microcontrollers (with narrower primary registers) are also cheaper. But they can have a lot of different peripherals and interfaces, so they can be used in many situations where advanced features are needed but not a fast CPU.
Smaller microcontrollers also generally require less power to operate, which is especially important for IoT and battery-powered devices. 7 .
Is firmware and data embedded in microcontrollers generally safe from downloading, tampering, or hacking?
No. Any code and data uploaded to a microcontroller should be thought of as being pretty easy to download and change, unless the microcontroller was built in a way that makes it impossible to download and change firmware. (Such hardened microcontrollers are usually expensive. ) 8 .
Describe the role of a watchdog timer.
Many microcontrollers have a watchdog timer, which is usually made with special hardware that can be used to see if the software that is running on the microcontroller got stuck.
Microcontrollers are designed to be sturdy and resilient. But there’s still any number of issues that can affect hardware stability. There can also be an unhandled combination of events on the software side. Both of these can cause microcontrollers to “hang,” either electrically or in an infinite loop in software.
A watchdog timer is a part of the system that needs to be told by the software that everything is working as it should within a certain amount of time. If the watchdog doesn’t get the message it’s looking for, it will do something, like reset the microcontroller or even the whole thing. This is usually done on a regular basis, and the watchdog timer will do what it needs to do if it doesn’t get a notification after a set amount of time has passed since the last notification. 9 .
Which of the following are the most important things about UART-based (also called RS-232-like and TTL-like) serial communication, I2C communication, and SPI communication?
Simple UART-based serial communication, with or without UART hardware, is the easiest communication protocol to set up, but it has a lot of problems:
- It’s intended to connect only two devices.
- It’s not synchronous, which means that the devices don’t agree on the clock rates.
- A slow bit rate (up to 115,200 bps) is where it’s most often used.
I2C can connect up to 127 devices on the same electrical bus, and each device is individually addressable. A “master” device makes a clock signal that all the other devices, which are called “slave devices,” can use. There is only one data wire, so all communication is unidirectional. (It’s commonly used to communicate with sensors on a PCB, which often use simple request-response protocols. ).
It’s made so that complex devices can talk to each other quickly and both ways. For example, a lot of data can be sent at once using the SPI bus. With SPI, the data and clock wires are shared by all devices. However, each device has its own addressing wires that let it talk to and from other devices. 10 .
Discuss a couple of options for wireless communication between embedded devices.
At the high end of the cost and difficulty scale, one of the wifi standards can be used to set up wireless communication. These offer great bandwidth, are interoperable with many other devices, and can be long-range. But wifi standards are also fairly complex and require dedicated hardware.
Bluetooth is a reasonable choice for interfacing between different types of hardware over short distances, i. e. , those of up to 15 yards (~14 meters). It also requires specialized hardware, but such hardware is usually cheap and simple to use. Devices using Bluetooth for communication often emulate a serial line between them.
Aside from WiFi and Bluetooth, there are also radio-based devices and protocols that work on the same frequencies (around 2 4 GHz), but with simpler protocols that are incompatible with the standard ones. They are usually cheaper than Bluetooth and simpler to implement.
There are also transceivers operating at low frequencies such as 433 MHz. They have very low bit rates over short distances (up to 9 meters or 10 yards), but they are very cheap and simple to set up. Solutions like LoRa, SigFox, and NB-IoT can be used if longer ranges are needed but a low bitrate is fine, which is often the case with IoT devices.
Finally, infrared communication over very short distances (a couple of yards) can also be an efficient choice.
There is more to interviewing than tricky technical questions, so these are intended merely as a guide. Not every good candidate for the job will be able to answer all of them, and answering all of them doesn’t mean they are a good candidate. At the end of the day, hiring remains an art, a science — and a lot of work.
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Embedded Software Engineering Interview Questions & Answers
FAQ
What is the basic knowledge of embedded system?
Why should we hire you as an embedded software engineer?
What is the highest salary for embedded system engineer?
How many embedded system interview questions are there?
Here are 19 embedded system interview questions with example answers: 1. Define the components of an embedded system. This question allows an interviewer to determine a candidate’s understanding of standard information about embedded systems. In your response, you can show your understanding by listing various components.
What questions should embedded engineers ask?
When asking this question, interviewers want to gauge your knowledge of the core components in embedded systems. Embedded engineers must understand the distinctions between microcontrollers and microprocessors, as they affect design choices, performance, and overall system architecture.
Why would an interviewer ask an embedded systems engineer a question?
There are a few reasons why an interviewer would ask this question to an embedded systems engineer. First, it allows the interviewer to gauge the engineer’s understanding of using commercial off-the-shelf components in embedded systems.
What should you do during an embedded engineer job interview?
Experts say the most important thing applicants should do during an embedded engineer job interview is be honest. You should also be ready to think on your feet. “It’s best, to be honest about what you know and what you don’t know. It is impossible for one engineer to know everything they need to know to build and test the entire system.
