Embedded Systems & Modern C/C++ Fundamentals
This area evaluates your ability to write correct, efficient, and maintainable embedded code that runs predictably under constraints. Expect to implement or review C/C++ for microcontrollers and embedded Linux targets, reason about UB, and discuss interfaces, memory layout, and testing.
Be ready to go over:
- Memory & Concurrency: stack/heap tradeoffs, lock-free vs. mutexed paths, ISR-safe code, ring buffers, atomics, and memory ordering.
- Embedded C++ Practices: RAII, strong typing, error handling without exceptions on constrained targets, templates vs. compile-time config.
- Testing Strategy: unit tests on host, on-target tests, fault injection, and CI coverage for embedded libraries.
- Advanced concepts (less common): MISRA C/C++ rationale, zero-copy pipelines, cache effects/NUMA, profile-guided optimizations, MC/DC coverage.
Example questions or scenarios:
- "Implement a fixed-size lock-free queue for an ISR-to-task handoff; explain memory ordering."
- "Refactor this callback-heavy driver API to a safer, testable interface; discuss error propagation."
- "Given this hexdump and register map, debug a misconfigured peripheral at boot."
Real-Time Systems, OS, and Driver Development
You’ll demonstrate how you select the right runtime (Linux vs. RTOS), structure threads/interrupts, and design drivers with clear contracts. You must reason about timing, jitter, scheduling, and failure containment.
Be ready to go over:
- RT Constraints: hard vs. soft real-time, latency budgets, scheduling policies, watchdogs.
- Drivers & Kernel: device tree, memory-mapped I/O, DMA, interrupts, and safe shutdown.
- Boot & Platform: secure boot, power sequencing, hypervisors/virtualization on NVIDIA platforms.
- Advanced concepts (less common): PREEMPT_RT tuning, lockdep/racy paths, A/B OTA strategies, sandboxing and SELinux/AppArmor profiles.
Example questions or scenarios:
- "Design the threading model for a 1 kHz control loop with sensor fusion at 200 Hz on a mixed RTOS/Linux stack."
- "Outline a secure boot and firmware update flow for a safety-critical ECU; handle rollback and key rotation."
- "Diagnose a sporadic 4 ms jitter spike after enabling a new DMA channel."
Vehicle Controls & Robotics Integration
Aurora evaluates how well you integrate embedded software with autonomy planning and control. You’ll discuss state machines, mode management, fault handling, and latency budgets from planner command to actuator response.
Be ready to go over:
- Control Loop Plumbing: command paths, signal conditioning, rate transitions, actuator saturation/limits.
- Fault Management: degraded modes, MRC (minimal risk condition), health monitoring, telemetry for root cause.
- Interfaces & Contracts: protobuf/IDL schemas, ROS 2/DDS QoS, time sync (PTP), and schema evolution.
- Advanced concepts (less common): control allocation, anti-windup, latency compensation, deterministic replay in HIL.
Example questions or scenarios:
- "Propose a state machine for mode transitions (manual, autonomous, degraded, MRC) with clear entry/exit criteria."
- "Budget end-to-end latency from planner to actuator; identify and mitigate jitter sources."
- "Design telemetry and on-road observability for a new control feature to support rapid debugging."
Safety, Reliability, and Validation
You will be asked how you build evidence for correctness. Expect to describe validation strategies across SIL/HIL, coverage targets, and fault injection—plus how you make these processes scalable and automated.
Be ready to go over:
- Test Architecture: SIL, PIL, HIL layers; golden logs; deterministic replays; simulators.
- Coverage & Standards: branch/condition coverage, MC/DC where applicable, coding guidelines, static/dynamic analysis.
- Diagnostics & Health: self-tests, startup checks, watchdog recovery, error budgets.
- Advanced concepts (less common): formal properties on critical modules, runtime invariants, safety case structure, FMEA.
Example questions or scenarios:
- "Define a HIL test to verify brake command limits and fail-safe on sensor dropout."
- "Choose coverage metrics for a fault manager; justify tradeoffs vs. schedule."
- "Walk through a production incident and the test you’d add to prevent recurrence."
Communication, Networking, and Platform Integration
Interviews probe how you integrate across buses and networks and make systems observable and resilient. You’ll discuss CAN, TCP/UDP, DDS, time sync, and failure strategies across distributed nodes.
Be ready to go over:
- Networking Basics: CAN FD framing, filters, bandwidth, QoS for DDS, TCP vs. UDP tradeoffs.
- Interoperability: schema evolution, backward compatibility, versioning, feature flags.
- Observability: logging, metrics, traces on embedded targets, rate limiting and retention.
- Advanced concepts (less common): redundancy, link failover, PTP boundary clocks, loss detection and recovery semantics.
Example questions or scenarios:
- "Design a CAN interface for actuator commands with safety checks and rate limiting."
- "Set DDS QoS profiles for planner-to-control topics to meet latency and reliability SLAs."
- "Instrument a control path for on-road debugging without violating real-time constraints."