Senior Embedded C++ System Design Showcase

This page highlights end‑to‑end embedded system designs, C++ patterns, and case studies suitable for a senior embedded C++ engineer portfolio and interviews.

Design principles (embedded + C++)

  • Determinism first: bounded latencies, ISR minimization, DMA offload, RTOS priorities.
  • Correctness and safety: volatile MMIO, race‑free lock strategies, W1C semantics, memory barriers.
  • Power/perf co‑design: DVFS, duty cycling, zero‑copy paths, cache‑aware data structures.
  • Robust comms: versioned binary protocols (TLV/CBOR), CRC/seq, backpressure, resumable transfers.
  • Secure by default: secure boot, key storage, least‑privilege, signed OTAs.

Reference stacks

  • Bare‑metal/RTOS pipeline: ISR → ring buffer → worker task → packetizer → transport (BLE/Wi‑Fi/USB) → storage/telemetry.
  • Android device controller: Kotlin UI + foreground service → AIDL/Binder → NDK/JNI parsers → USB/BLE/Wi‑Fi transports.

Case studies (deep dives)

  • Lidar + Android controller (single‑device embedded design): /blog_cpp/2025/10/29/embedded-single-device-design-android-lidar/
  • Port I/O read/write (8/16/32‑bit, barriers, endianness): /blog_cpp/2025/10/29/embedded-port-io-read-write/
  • USB reader/writer (CDC‑ACM + libusb bulk): /blog_cpp/2025/10/29/usb-reader-writer-embedded-cpp/
  • Android USB Host (CDC/Bulk) in Kotlin: /blog_cpp/2025/10/29/android-usb-reader-writer/
  • PCI config/MMIO access from C++ (libpci + mmap): /blog_cpp/2025/10/29/pci-read-write-with-cpp/
  • Matter/CHIP device/controller examples: /blog_cpp/2025/10/29/matter-with-cpp-intro-and-examples/

C++ patterns that scale on MCUs/SoCs

  • Zero‑cost abstractions; span/string_view for bounds‑aware views.
  • std::atomic with precise memory orders; lock‑free ring buffers for ISR↔task.
  • RAII for DMA/lock lifetimes; gsl::final_action for cleanup.
  • Fixed‑capacity allocators; intrusive containers for no‑heap regions.
  • Parse/serialize with constexpr tables; small‑buffer optimization where applicable.

Performance & reliability playbook

  • Latency budget: instrument ISR to app; flame‑graph the pipeline; budget per hop.
  • Throughput: chunk sizing vs. MTU, double‑buffering, cache‑line alignment, prefetch.
  • Resilience: watchdog strategy, brownout handling, write‑amortized flash logging.
  • Power: measure in mA over modes; A/B experiments for ML/compression vs. battery.

Security & OTA

  • Chain‑of‑trust boot, KeyMint/TEE (Android) or MCU secure elements.
  • Signed delta OTAs with resume; staged rollouts; rollback guards.

Measurement & test

  • Hardware‑in‑the‑loop record/replay; determinism gates; RF and thermal scenarios.
  • Fuzz binary parsers; property tests for TLV/CBOR; CRC/seq corruption tests.

Interview checklist (senior)

  • State workloads, latencies, and power targets early; quantify.
  • Show ISR→task design, buffer sizes, and backpressure math.
  • Prove C++ API choices (RAII, atomics, no hidden allocations) and testing strategy.
  • Cover failure drills: sensor faults, thermal, link drops, OTA aborts.