Interview Question Bank

Core C/C++ programming skills and low-level concepts essential for embedded development

• What does the keyword volatile mean? Give three examples of its use.
• Can a variable be both const and volatile? Give a real example.
• Does volatile make a variable access atomic?

Compilation pipeline, toolchains, linker scripts, memory layout, and binary inspection

• Walk me through what happens when you press "Build" on a typical embedded C project.
• What's the difference between .data and .bss?
• How do you place an array or function at an exact address (e.g., a DMA buffer or a firmware version block)?

CPU fundamentals, MCU cores, boot process, interrupts, and driver design

• Describe what happens from power-on until main() is called on a Cortex-M microcontroller.
• Explain cache coherency issues with DMA and how to solve them.
• When would you use HAL vs bare-metal register access? Give a real example.

Essential peripheral interfaces and communication protocols

• How do you calculate the voltage represented by one LSB, and why does it matter?
• What is CAN and why is it the dominant bus in automotive and industrial systems?
• When should you use DMA instead of CPU-driven data transfers?

Real-time programming concepts, task scheduling, and RTOS fundamentals

• What is the difference between a general-purpose OS and a real-time OS (RTOS)?
• What is the RTOS tick and how does it affect system behavior?
• What is context switching and what happens during one?

FSM fundamentals, implementation patterns, event-driven design, and hierarchical state machines

• Mealy vs Moore — which is more common in firmware?
• How do you test a state machine effectively?
• When would you choose table-driven over switch-case?

TCP/IP, sockets, MQTT, HTTP/REST, and TLS for embedded connectivity

• Explain the TCP/IP layer model and how it applies to embedded systems.
• TCP vs UDP — when to use each in embedded systems?
• What is the sockets API and how does it map to embedded networking?

BLE, WiFi, LoRa, cellular IoT, UWB, and mesh networking for embedded systems

• Explain the BLE protocol stack — GAP, GATT, ATT, and L2CAP
• What is the difference between BLE advertising mode and connected mode?
• How do you optimize BLE for battery life on a wearable device?

Linux kernel basics, build systems, and user-space programming

• Walk through the embedded Linux boot sequence from power-on to application.
• What is U-Boot and what does it do?
• What is initramfs and when do you need it?

Debugging techniques, testing strategies, power profiling, and development tools

• Compare JTAG and SWD for debugging embedded systems. When would you choose one over the other?
• How do you debug a hard fault on ARM Cortex-M? Walk through the process from the moment the fault triggers.
• Your embedded application crashes intermittently — describe your systematic debugging approach.

Safety standards, security fundamentals, OTA updates, and reliability engineering

• What is ISO 26262 and what are ASIL levels?
• Compare IEC 61508, ISO 26262, and IEC 62304 — which applies when?
• What is MISRA C and why does it matter for embedded development?