MCU programmer's interview experience and suggestions

Single chip microcomputer STM32L151CCU6

1206RGB (single)

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

What skills do you need to master?

● Understand and work with common microcontrollers like STM32, PIC, or AVR.

● Be familiar with hardware communication protocols such as UART, SPI, and I2C.

● Have basic knowledge of sensors—like light, sound, temperature, and magnetic sensors—and how they interface with microcontrollers.

● Know how to read datasheets and configure registers for peripheral devices using code.

● Be able to interpret schematics and understand PCB layouts.

● Use tools like oscilloscopes to debug and analyze circuits.

What is the actual interview like?

● Basic C programming and algorithm problems are often asked during interviews.

● Interviewers might ask about project experience, design approaches, and problem-solving methods.

What’s actually used in the job?

I’ve found that most of my interview success came from small companies focused on MCUs. These teams were small, and the projects were usually manageable by a few people. While I can write code well, I struggle with algorithm questions. It's frustrating because I've been studying a lot lately, but I still feel that the algorithms I learned aren’t really used in embedded systems. Most of the time, I just follow existing code without thinking deeply about it.

Back when I was in school, I realized that data structures and algorithms weren’t always necessary for microcontroller development. But I also saw that some algorithms—especially those related to signal processing—are extremely useful. I even bought a book on embedded system algorithms before graduating. It turned out to be a great resource. Many of those techniques fall under DSP (Digital Signal Processing), which deals with digital signals from sensors. Processing this data and sending it back through a controller or communicator is what makes embedded systems functional.

A bit of insight:

Over the years, I've worked on several MCU-based projects, but none of them were truly successful or scalable. The power detection device I once developed with PIC microcontrollers was made in small quantities, but it never became a product I could be proud of. Every time I look for a new job, I wonder how much effort I’ve actually put into these projects. They’ve felt more like a job than a passion. Even though my technical skills have improved over time, I’ve lost the excitement I had when I first started learning. Now, I'm exploring other areas in my free time, seeing embedded systems more as a means to an end rather than a field of interest.

Recently, I've been working with embedded Linux, which has taught me a lot about OS-level programming, networking, and file handling—things I hadn't used before. I now realize that many of the things I wanted to implement on MCUs, like real-time operating systems or multi-threading, are much easier to handle under an OS. Writing multi-threaded code brings up complex issues like synchronization and mutual exclusion, which are far more challenging than just running tasks sequentially.

Working with video and audio streams also requires careful buffer management and timing control. In MCU development, you have to pay close attention to the physical world and translate analog signals into digital data. Real-time constraints and simple program structures are essential for reliable performance.

A little advice:

● Always remember that your growth and learning matter most. Don’t get stuck in the same technology stack. I've seen software engineers transition into MCU development, and it can be incredibly rewarding to interact directly with the physical world.

● Keep learning. This industry is still evolving, and there’s always something new to explore. It’s rare to see someone who stays in the same role for 20 years. Stay curious and keep improving—this is what makes a good engineer.

● MCU programmers are software engineers too. We solve real-world problems, and our work is just as valuable as any other type of software development. While we may be seen as "hardware" engineers, the difference between us and others is similar to the difference between writing Java and Python. No one becomes a great programmer without continuous learning, unless they move into management roles.