Job Interview Questions for Embedded Systems Developers

You’re applying for a position as an embedded systems developer. Are you ready for the questions a hiring manager is likely to ask? Check your answers for these 38 questions to prepare for the job interview.

Job interviews are stressful and awkward at the best of times. It’s hard to relax and talk about your work experience even when you know the subject matter in depth. One common way to prepare for a job interview is to review typical questions for the role and brush up on anything new in the field you might have missed. In addition to generic job-search resources, you can find help in books specific to software development careers, such as Land theTech Job You Love and Cracking the Coding Interview.

However, few guides to job interview questions are tuned to embedded systems developers. The questions discussed here are tailored for developers who write software for use in robotics, IoT, automotive architecture, and aerospace design. While the questions are primarily meant for people with an #OpenToWork hashtag on their LinkedIn profiles, they’re equally useful for hiring managers.

Domain-Expertise Questions

Most interviewers ask about a candidate’s experience with the tools and platforms the employer uses, hoping to find someone familiar with its current suite. The job requisition generally clues you into the tools they care about, so be prepared to describe when and how you used them.

• What is your work experience with embedded C++, JTG debugging, and the Yocto Project?

Don’t fret if your experience is not a direct match. But expect to explain how your background intersects with those tools and your willingness to adopt them. For instance, if the job req says, “We prefer someone with experience developing applications for VxWorks, FreeRTOS, or another real-time operating system,” prepare to describe your opinions of the RTOSes you worked with. Think of it as a compare-and-contrast question rather than an expectation to say that VxWorks is the best. If it’s been a while since you used the tool, draw on online research (such as reading about the features in the latest VxWorks release) to demonstrate that you’re paying attention.

For many hiring managers, it doesn’t really matter which RTOS you worked with, as long as you’re familiar with one of them. It’s common for embedded software projects to modify custom builds, configurations, testing, and development systems. The concepts transfer from one environment to another.

Still, be realistic about your skill set. Embedded software platforms have a wide scope. If you have extensive experience with microcontroller RTOSes, you might not be the best candidate for a position that requires a lot of Linux device driver work.
It is not a sign of career doom to lack deep familiarity with a given tool. The hiring manager may instead be impressed with a breadth of knowledge. For instance, software and firmware engineers sometimes need to port code to a different operating system (OS). You might have adapted an OS for custom hardware. That OS porting expertise might be more germane to the position than in-depth knowledge of any given RTOS.

Besides, you can never be sure whether the job listing captures everything on the company’s wish list or correctly emphasizes what’s important to the hiring manager. Expect to be asked about tools that support the development process:

• Which source code control systems do you use?
• How has the team you’ve served on used Agile methodologies? What’s your Scrumexperience?
• What kind of continuous integration pipeline have your projects used? Was it integrated with a tracking system such as Jira?

The domain expertise extends beyond the tool suite:

• How well do you know the standards that apply to the work we do? Have you worked on projects that mandate compliance with government standards?
• Give some examples of how you used cybersecurity methodologies, tools, and techniques to prevent risks and issues, and to address those that emerge.
• The application we’re building is mission-critical. It cannot fail. Our developers need to consider failure modes, conditions, results, and ways to mitigate them. Your resume shows plenty of experience building hardware-centric applications, but I’m not sure how many were mission-critical. Tell me more.

This is an opportunity to mention experience with related tools. For instance, a candidate with open projects on github often inspires the hiring manager’s confidence.

Coding Questions

The hallmarks of embedded systems interviews are questions about packed and aligned data structures, endianness, toolchains, and bitwise operations.
You may be asked to perform a coding task to assess programming ability. For example, you may be asked to sort the characters in a string in place or to reverse a linked list. Expect assignments written in C or C++ and requirements for at least a read-only understanding of Assembly language. Extra points for mentions of Arm, RISC-V, PowerPC, or Cortex on your resume.
Alternatively, you might be asked about application design:

• Tell me how you would write a short program that is endian-agnostic.

The interviewer might show you some code and then ask questions to estimate your understanding: “Given bar, how can we readout d?” or “Where does the value of _padoriginate?”

Nomenclature Lightning Round

Interviewers commonly ask open-ended questions about technology fundamentals, particularly when a job applicant has relatively little experience. In the best circumstance, it’s a checkbox so the interviewer can confirm how well the candidate understands the topic.

Some questions may be “pop quiz” explainers — “define this RTOS term” — more like a college exam than a measure of your expertise. Whatever you think of such questions, it’s a goodidea to review your answers before the interview.

A basic answer is fine. Don’t stress over these, and don’t be insulted if the questions seem too basic for your career level. The query may serve as an entry point for a discussion of how the company uses that technology and how it applies to the role. For example, the interviewer might ask you, “What are the differences in the types of flash memory?” because their work involves getting file systems to operate on low-cost, nonvolatile storage. They hope you know that Micron Q SPI Flash is a “raw” flash that doesn’t include built-in wear leveling, so it requires a file system such as JFFS2 to provide that functionality. Other examples:

• What are the heap and the stack, and why does it matter?
• What is the difference between a process and a thread? How does an interrupt work?
• RTOS coding is more constrained than general C++. What practices are common in
  C++ that might not be common in an RTOS?
• What is an interrupt handler? What are some good coding practices for them? Howdo they interoperate with other code?
• What are core dumps and stack traces? How do you use them?
• What are the differences between TCP and UDP?
• What is a task (or thread) in RTOS?
• Describe the difference between a mutex and a semaphore.
• What is priority inversion, and how can it be handled? What is static?
• What is volatile?
• What programming practices should typically be avoided in embedded systems, andwhy?
• Compare and contrast I2C, UART, and SPI.
• When should you poll registers rather than use IRQs?
• Explain the role of interrupts in embedded systems and how you manage them to optimize system performance.

If you don’t know the answers to these questions offhand, that’s OK. They may not apply to the embedded software job to which you’re applying. However, a gulp of nervousness suggests that you should refamiliarize yourself with the technologies you are being quizzed on. For a refresher course, Shape the World is a good starting point. So is this Serial Communications basics overview and Proximity Networking: Essential Wireless Standards.

Process Questions

Everyone’s favorite job interview questions involve personal experiences. “Asking specific questions about work experiences can help discern if a candidate is a good fit,” says Himanshu Agarwal, cofounder of Zenius, a recruitment company that recently found remote embedded system developers for a tech company client scaling its IoT development. “Asking about situations where they had to pivot their approach during the late stages of development, for example, can show a candidate’s resourcefulness.”

Interviewers gravitate toward experience- and process-oriented questions because they illuminate how the job candidate thinks, how they solve problems, and (at least to some degree) what it will be like to work with them. It’s an opportunity for team-bonding before you are on the team.
The most general of these questions is:

• Can you give an overview of your experience as an embedded software engineer,
  including the types of projects you have worked on?

Ideally, the interviewer’s questions encourage you to talk about interests and skills that may not be apparent from a resume.

• Describe a project you were involved in that was particularly challenging or rewarding.

This type of question frequently comes up, so it pays to spend some time before the interview reflecting on past projects that were either interesting or problematic; those can be difficult to recall under interview pressure.

• Tell me about a project you enjoyed working on. What did you love about it? Please walk me through the tech you used. 

It’s OK to share something work-related or talk about a volunteer project. (I made the smallest possible USB device! Or I created a tool for visualizing embedded data.)

Nobody works alone, so some questions for embedded systems developers focus on how you collaborate. “Our interviewing team reported getting the most insight from questions about the strategy candidates follow to maintain code quality and documentation on a distributed team,” says Agarwal.

• Tell me about your experience interacting with testing organizations.
• What role did you play in resolving the issue you just described? Who came up withthe design you implemented?

Most organizations prefer candidates who collaborate during the development process rather than those who view bug reports on their work as antagonistic.

• How do you approach troubleshooting a crashing system or application? Whatdebugging tools and techniques do you use? 

Even if this sounds like a technical question — and it certainly can lead to a discussion about testautomation tools for embedded systems — this is a way for you and the interviewer to discover what it would be like to work together.

• Which embedded-related code bases have you looked at? 

It’s a truism that reading other people’s code is a good way to improve your programming skills. For example, sharing what you learned from an OpenVX implementation for CV/ML hardware abstraction layers, audio processing, or proper memory management for resource-constrained devices, portability, and networking stack basics demonstrates your technical acumen as well as the topics that interest you.

• How do you improve your skills as an embedded system developer?

Expected answers might include the online communities you participate in, the publications yousubscribe to, books you read (say, Test-Driven Development for Embedded C), the open sourceprojects you contribute to, or the courses you take at Microchip University.

• Tell me about your worst bug.

Nobody can resist this sort of storytelling. Be sure to ask the interviewer about their worst bug, too. You can commiserate. Ultimately, a good job interview is a conversation, not a quiz show.

Need more practice questions?

• Tell me about a project where you had to design and implement a system with strict power, memory, and processing constraints.
• How are you using AI in your embedded toolbox? Where do you think it’s headed?
• What is your experience with device driver development?
• Describe a situation where you had to optimize an embedded system for performanceor power consumption. What were the trade-offs you considered? What techniques didyou use? 

If you are genuinely interested in embedded systems development, don’t forget to look at Wind River’s job openings. Perhaps you can contribute to improving the tools that make the work possible.

Happy job hunting!