automotive-embedded-skills

name automotive-embedded-skills description C/C++/CAPL best practices for automotive embedded systems. This skill should be used when writing, reviewing, or refactoring embedded C/C++ code or CAPL scripts targeting automotive ECUs, following MISRA, AUTOSAR, ISO 26262, and ISO 21434 guidelines. Triggers on tasks involving embedded firmware, CAN/CAN FD/LIN/Ethernet communication, TCP/UDP/DoIP/SOME-IP protocols, RTOS programming, safety-critical code, cybersecurity, diagnostics (UDS), CAPL test automation, or calibration toolchain integration. license MIT metadata {"author":"automotive-embedded-engineering","version":"2.0.0"} Automotive Embedded C/C++/CAPL Best Practices Comprehensive coding guidelines for automotive embedded software development in C, C++, and CAPL. Contains 180+ rules across 23 categories, prioritized by safety impact and industry compliance requirements (MISRA C:2012, MISRA C++:2023, AUTOSAR C++14 Classic & Adaptive, ISO 26262, ISO 21434). Covers full automotive communication stack (CAN/LIN/Ethernet/IP/TSN), cybersecurity, diagnostics, CAPL simulation/testing/fault injection, AUTOSAR BSW modules, boot/NVM/power management, compiler toolchains, static analysis tools, and CI/CD integration. When to Apply Reference these guidelines when: Writing new embedded C/C++ modules for automotive ECUs Implementing or reviewing CAN/LIN/Ethernet communication stacks Writing CAPL scripts for CANoe/CANalyzer simulation and testing Refactoring code for MISRA C/C++ or AUTOSAR C++14 compliance Designing safety-critical software (ASIL A-D per ISO 26262) Implementing RTOS task management and inter-task communication Reviewing code for memory safety, timing, and determinism Working with diagnostic protocols (UDS, OBD-II, DoIP) Implementing Automotive Ethernet (TCP, UDP, SOME/IP, DoIP, VLAN) Addressing cybersecurity requirements (ISO 21434, secure boot, TLS) Integrating with calibration/diagnostic tools (A2L, ODX, XCP) Optimizing for resource-constrained microcontrollers (RAM, Flash, CPU) Rule Categories by Priority Priority Category Impact Prefix 1 Memory Safety & Management CRITICAL memory- 2 MISRA C/C++ Compliance CRITICAL misra- 3 AUTOSAR C++14 Guidelines (Classic & Adaptive) CRITICAL autosar- 4 Safety & Functional Safety (ISO 26262) HIGH safety- 5 Real-Time & Timing Constraints HIGH realtime- 6 Communication Protocols (CAN/LIN/Ethernet/IP/UDS) HIGH comm- 7 Concurrency & RTOS Patterns MEDIUM-HIGH rtos- 8 CAPL Scripting — CANoe MEDIUM-HIGH capl-canoe- 9 CAPL Scripting — vTESTstudio MEDIUM-HIGH capl-vtest- 10 Code Organization & Architecture MEDIUM arch- 11 Performance Optimization MEDIUM perf- 12 Build, Compilation & Static Analysis MEDIUM build- 13 Security & Cybersecurity (ISO 21434) HIGH security- 14 Testing & Verification MEDIUM test- 15 Tool Integration (A2L/ODX/FIBEX) MEDIUM integration- Quick Reference 1. Memory Safety & Management (CRITICAL) memory-stack-over-heap - Prefer stack allocation over heap in embedded context memory-static-allocation - Use static allocation for deterministic memory usage memory-buffer-bounds - Always validate buffer boundaries before access memory-pool-pattern - Use memory pool patterns for dynamic-like allocation memory-no-malloc-in-rt - Never use malloc/free in real-time critical paths memory-raii-cpp - Use RAII for resource management in C++ embedded code memory-volatile-correctness - Use volatile correctly for hardware registers and shared data memory-alignment - Ensure proper data structure alignment for target architecture memory-zero-init - Always initialize variables, especially in safety-critical code 2. MISRA C/C++ Compliance (CRITICAL) misra-no-implicit-conversions - Avoid implicit type conversions misra-single-exit-point - Prefer single function exit point for critical functions misra-no-dynamic-memory - Avoid dynamic memory allocation (Rule 21.3) misra-no-recursion - Avoid recursion in embedded context (Rule 17.2) misra-switch-default - Always include default case in switch statements misra-no-goto - Avoid goto except for error cleanup patterns in C misra-boolean-expressions - Use explicit boolean comparisons misra-pointer-arithmetic - Restrict pointer arithmetic to array indexing misra-side-effects - Avoid side effects in conditional expressions 3. AUTOSAR C++14 Guidelines (CRITICAL) autosar-smart-pointers - Use smart pointers instead of raw pointers for ownership autosar-no-exceptions-rt - Avoid exceptions in real-time contexts, use Result types autosar-const-correctness - Apply const-correctness throughout interfaces autosar-override-final - Always use override/final for virtual function overrides autosar-enum-class - Use enum class instead of plain enum autosar-no-unions - Avoid unions, use std::variant when needed autosar-braces-init - Prefer braced initialization to prevent narrowing autosar-nodiscard - Use [[nodiscard]] for functions with important return values 4. Safety & Functional Safety - ISO 26262 (HIGH) safety-defensive-programming - Apply defensive programming at module boundaries safety-error-detection - Implement error detection and plausibility checks safety-redundant-checks - Use redundant checks for critical control paths safety-watchdog-pattern - Implement watchdog monitoring patterns safety-state-machine-integrity - Protect state machine transitions from corruption safety-crc-validation - Validate data integrity with CRC for critical data safety-safe-state - Always define and reach safe state on failure safety-asil-decomposition - Follow ASIL decomposition patterns correctly 5. Real-Time & Timing Constraints (HIGH) realtime-deterministic-execution - Ensure deterministic execution time in cyclic tasks realtime-wcet-awareness - Design with WCET (Worst-Case Execution Time) in mind realtime-no-blocking-isr - Never block in interrupt service routines realtime-priority-inversion - Prevent priority inversion with proper locking realtime-cyclic-scheduling - Follow cyclic scheduling patterns correctly realtime-interrupt-latency - Minimize interrupt latency and ISR execution time realtime-deadline-monitoring - Implement deadline monitoring for critical tasks 6. Communication Protocols (HIGH) CAN / LIN Bus: comm-can-message-layout - Follow proper CAN/CAN FD message layout and DBC conventions comm-can-error-handling - Handle CAN bus-off recovery and error frames comm-can-fd-handling - Handle CAN FD extended data length and bit rate switching comm-lin-schedule-table - Implement LIN schedule tables and response handling comm-signal-timeout - Implement signal timeout monitoring with default values comm-network-management - Follow NM (Network Management) state machine correctly Automotive Ethernet / IP Stack: comm-tcp-socket-lifecycle - Manage TCP socket lifecycle (connect, keepalive, graceful shutdown) comm-udp-datagram-handling - Handle UDP datagrams for service discovery and streaming comm-doip-implementation - Implement Diagnostics over IP (ISO 13400) activation and routing comm-arp-table-management - Manage ARP tables and static ARP entries for deterministic networks comm-icmp-handling - Handle ICMP for network diagnostics and reachability detection comm-vlan-qos-priority - Configure VLAN tagging and QoS priority mapping (IEEE 802.1Q) comm-dhcp-autoip - Implement IP address assignment (DHCP client, AutoIP fallback) comm-someip-serialization - Use correct SOME/IP serialization for service-oriented communication comm-someip-sd - Implement SOME/IP Service Discovery (offer, find, subscribe) Diagnostics & Routing: comm-uds-service-handler - Implement UDS diagnostic services with proper NRC handling comm-gateway-routing - Implement proper message routing in gateway ECUs 7. Concurrency & RTOS Patterns (MEDIUM-HIGH) rtos-task-design - Design tasks with single responsibility and proper priority rtos-critical-section - Minimize critical section duration rtos-mutex-pattern - Use mutexes correctly, avoid nested locking rtos-message-queue - Prefer message queues over shared memory for inter-task communication rtos-no-priority-inversion - Use priority inheritance or ceiling protocols rtos-isr-to-task - Defer ISR processing to task context via flags/queues rtos-stack-sizing - Size task stacks correctly with safety margin 8. CAPL Scripting — CANoe (MEDIUM-HIGH) capl-canoe-message-handler - Structure message handlers for readability and performance capl-canoe-timer-pattern - Use timer patterns correctly for cyclic and one-shot operations capl-canoe-test-structure - Structure test cases with proper setup/teardown/verification capl-canoe-signal-access - Access signals via database symbols, not raw byte manipulation capl-canoe-error-frame-handling - Handle error frames and bus-off conditions in simulation capl-canoe-environment-variables - Use environment variables for panel interaction correctly capl-canoe-diagnostic-testing - Implement diagnostic request/response testing patterns capl-canoe-node-simulation - Design node simulation with proper state machines capl-canoe-multi-channel - Multi-channel bus simulation (CAN+CAN, CAN+LIN, CAN+ETH) capl-canoe-rbs-cyclic - Cyclic Rest Bus Simulation with counter/CRC generation capl-canoe-rbs-reactive - Reactive RBS with Interaction Layer and state-dependent responses capl-canoe-gateway-routing - Gateway simulation with signal/PDU/cross-protocol routing 8b. CAPL — Shared Patterns (MEDIUM-HIGH) capl-signal-manipulation - Reusable signal manipulation library (ramp, sine, noise, step, sequence) 8c. CAPL — Fault Injection (HIGH) capl-fault-can - CAN/CAN FD fault injection (error frames, bus-off, signal stuck, timing) capl-fault-lin - LIN fault injection (checksum, no-response, header, timing) capl-fault-eth - Ethernet fault injection (link down, packet loss, latency, corruption) 8d. CAPL — External Integration (MEDIUM) capl-ext-dll-integration - CAPL DLL API, data exchange, thread safety, 32/64-bit capl-ext-com-python - CANoe COM automation via Python capl-ext-com-csharp - CANoe COM automation via C# capl-ext-ci-cd - CI/CD integration (Jenkins, GitLab CI, headless execution) 9. Code Organization & Architecture (MEDIUM) arch-hal-abstraction - Use Hardware Abstraction Layer for portability arch-module-interface - Design clean module interfaces with information hiding arch-state-machine - Implement state machines with table-driven or state-pattern approach arch-callback-pattern - Use callback patterns for decoupling layers arch-config-separation - Separate configuration from logic (calibration parameters) arch-layered-architecture - Follow layered architecture (MCAL, ECU-AL, BSW, SWC) 10. Performance Optimization (MEDIUM) perf-loop-optimization - Optimize loop constructs for embedded targets perf-lookup-table - Use lookup tables instead of runtime computation perf-bitwise-operations - Use bitwise operations for flag and register manipulation perf-cache-friendly - Organize data for CPU cache efficiency perf-inline-critical - Inline small, critical functions perf-fixed-point - Use fixed-point arithmetic instead of floating-point when possible perf-dma-usage - Use DMA for bulk data transfers 11. Build, Compilation & Static Analysis (MEDIUM) build-warnings-as-errors - Treat all compiler warnings as errors build-static-analysis - Integrate static analysis (PC-lint, Polyspace, Coverity) build-compiler-flags - Use appropriate compiler flags for safety and optimization build-link-time-optimization - Use LTO for cross-module optimization build-reproducible-builds - Ensure reproducible builds for traceability 12. Testing & Verification (MEDIUM) test-unit-test-pattern - Structure unit tests for embedded C/C++ (Unity, Google Test) test-mock-hardware - Mock hardware dependencies for testability test-boundary-values - Test boundary values and edge cases systematically test-coverage-targets - Meet code coverage targets per ASIL level test-integration-testing - Design integration tests for inter-module communication test-hil-sil-pattern - Structure HIL/SIL test patterns for verification 13. Security & Cybersecurity — ISO 21434 (HIGH) security-secure-boot - Implement secure boot chain verification security-secure-communication - Use TLS/DTLS for in-vehicle Ethernet communication security-key-management - Handle cryptographic keys with proper storage and rotation security-secure-diagnostics - Implement secure UDS authentication (0x29 service) security-input-sanitization - Sanitize all external inputs (CAN, Ethernet, diagnostic) security-secure-update - Implement secure OTA/reflash with signature verification security-access-control - Enforce access control between security domains security-crypto-usage - Use cryptographic primitives correctly (AES, HMAC, CMAC) 14. MISRA Grouped Topics (CRITICAL) misra-type-system - Essential type model, implicit conversions, type casting (Rules 10-11) misra-control-flow - Switch, goto, unreachable code, single exit (Rules 15-16) misra-pointer-safety - Pointer arithmetic, null checks, conversions (Rules 18, 11) misra-declarations - Variable scope, linkage, storage class (Rules 8) misra-expressions - Side effects, precedence, boolean, sizeof (Rules 12-14) misra-functions - Prototypes, parameters, return values, recursion ban (Rules 17) misra-preprocessor - Macro safety, include guards, conditional compilation (Rules 20) misra-standard-library - Banned functions, restricted headers (Rules 21-22) misra-initialization - Variable/array/struct initialization (Rules 9) misra-memory-model - Volatile, atomic access, memory barriers (Rules 19) misra-concurrency - Thread safety, shared data access (Amendment 4) misra-deviation-process - Deviation documentation, approval, common patterns 15. AUTOSAR Classic BSW Modules (HIGH) autosar-classic-ecum - EcuM startup/shutdown, sleep/wakeup autosar-classic-bswm - BswM mode arbitration, action lists autosar-classic-com - COM signal packing, transmission modes autosar-classic-pdu-router - PDU Router routing paths, gateway autosar-classic-dcm-dem - Dcm/Dem diagnostics, DTC management autosar-classic-nvm - NvM block configuration, CRC, read/write autosar-classic-os - AUTOSAR OS tasks, ISRs, resources, alarms autosar-classic-canif-cantp - CanIf/CanTp callbacks, flow control 16. AUTOSAR Adaptive ara:: APIs (HIGH) autosar-adaptive-ara-com - ara::com proxy/skeleton, service discovery autosar-adaptive-ara-core - ara::core Result<T,E>, ErrorCode, Future autosar-adaptive-ara-exec - ara::exec process lifecycle, function groups autosar-adaptive-ara-diag - ara::diag diagnostic services autosar-adaptive-ara-log - ara::log logging patterns autosar-adaptive-ara-phm - ara::phm health management, supervision autosar-adaptive-ara-per - ara::per persistency, key-value storage 17. ECU Boot Sequence (HIGH) boot-baremetal-startup - Bare-metal boot: startup → C runtime → main boot-autosar-classic-startup - Classic AUTOSAR EcuM/BswM boot boot-autosar-adaptive-startup - Adaptive Execution Manager boot boot-bootloader-reprogramming - UDS flash download sequence boot-secure-boot-chain - Secure boot with HSM verification 18. NVM Management (HIGH) nvm-autosar-block-config - AUTOSAR NvM blocks, CRC, redundancy nvm-fee-ea-abstraction - Fee/Ea Flash EEPROM Emulation nvm-baremetal-flash - Bare-metal Flash/EEPROM patterns nvm-wear-leveling - Wear leveling strategies for automotive lifetime 19. Power Management (MEDIUM) power-ecum-sleep-wakeup - EcuM sleep/wakeup state machine power-partial-networking - Partial networking, selective transceiver wakeup power-bswm-shutdown - BswM ordered shutdown action lists power-clock-peripheral - Clock gating and peripheral power-down