OS-Aware Debugging (AUTOSAR/OSEK) - Debugging & Tracing

ORTI Files and OS Awareness

AUTOSAR OS Debug Architecture

  AUTOSAR OS Generator (e.g., ETAS RTA-OS, EB tresos)
  └── Generates OIL/ARXML config
       │  Also generates .orti file (Object Reference and Task Information)
       ▼
  .orti file: maps OS internal symbols to TRACE32 names
  ├── Task control blocks (TCB): stack base, stack size, state, priority
  ├── Resource and spinlock IDs
  └── Alarm and schedule table objects

  TRACE32 load:
  TASK.CONFIG .orti
  TASK.List            → shows all tasks with state/priority/stack info

  Task states (AUTOSAR):
  SUSPENDED → READY → RUNNING → WAITING (extended tasks only)
  ISR2: preempts any task; nested up to platform limit

Task-Level Debugging in TRACE32

CMMtask_debug.cmm

// AUTOSAR OS task debugging

// Load OS awareness after connection
TASK.CONFIG gen/Os_Debug.orti

// List all tasks: state, priority, current stack usage
TASK.List

// Switch debugger context to a specific suspended task
TASK.select "OsTask_10ms"    // view that task's saved register context
Frame.view /Locals /Caller   // call stack within that task
Var.Watch %Open (App10ms_State_t *)g_app10ms   // task-local variables

// Set breakpoint that fires only when a specific task is active
Break.Set App_10ms_Runnable /Program /TASK "OsTask_10ms"
// This breakpoint is ignored when the same PC is reached from OsTask_100ms

// Watch for task state transitions (PreTask/PostTask hooks)
Break.Set Os_PreTaskHook /Program    // fires on every task activation
// In hook: read Os_GetActiveApplicationMode() / Os_GetTaskID()

// Detect task overrun (execution time > period)
// Set time measurement: start at task entry, check at task exit
Break.Set OsTask_10ms_entry /Program
Break.Set OsTask_10ms_exit  /Program

// Automate task timing logging
// See runtime-measurement-profiling lesson for full implementation

Debugging Interrupt Service Routines

CMMisr_debug.cmm

// ISR debugging: breakpoints in ISR context

// ISR2 in AUTOSAR: scheduled by OS, can call OS services
// ISR1: hardware-only, cannot call OS services; very restricted

// Set breakpoint inside CAN receive ISR
Break.Set Can_RxISR_Handler /Program

// When halted in ISR: inspect interrupt controller state
PRINT "Active IRQ: " Data.Long(SFR:SCB.ICSR) & 0x1FF   // bits 8:0 = VECTACTIVE
PRINT "Interrupt nesting depth: " Data.Long(SFR:SCB.ICSR) & 0x200  // bit 11 = RETTOBASE

// On Aurix: interrupt service registers
PRINT "SRC_CAN0SRN0: " Data.Long(SFR:SRC_CAN0SRN0)  // service request register

// Detect ISR stack overflow (separate MSP stack on Cortex-M)
LOCAL &msp_base &msp_current
&msp_base=0x20000000    // main stack base (from linker script)
&msp_current=Register(MSP)
PRINT "MSP: " FORMAT.HEX(8.,&msp_current) "  Used: " (&msp_base-&msp_current) " bytes"
IF &msp_current < (&msp_base - 0x400)
    PRINT %ERROR "MSP within 1 kB of stack limit!"

// Measure ISR latency: time from IRQ trigger to first ISR instruction
// Requires ETM trace — see hardware-trace-etm-mcds lesson

OS Hooks for Debug Instrumentation

Hook	Trigger	Debug Use
PreTaskHook	Before task starts running	Log task activation timestamp; measure context switch time
PostTaskHook	After task releases CPU	Log task exit; compute actual execution time vs period
ErrorHook	OS error (E_OS_RESOURCE, E_OS_ACCESS, etc.)	Log error code + calling context; set TRACE32 breakpoint
ProtectionHook	MPU violation, stack overflow, timing violation	Safety: log violation type + faulting task; trigger reset
StartupHook	After OS init before first task runs	Initialize debug buffers, ETM trace, cycle counters

Summary

OS awareness transforms TRACE32 from a low-level register debugger into an application-level debugging tool: tasks are named and navigable, breakpoints can be scoped to a specific task, and the call stack shows meaningful function names within the task's context rather than a confusing mix of OS and application frames. The .orti file is the bridge — always regenerate it alongside the OS configuration to keep TRACE32's symbol map in sync. Task-scoped breakpoints eliminate the most frustrating type of false halt: a breakpoint in a shared function that fires from the wrong task context.

🔬 Deep Dive — Core Concepts Expanded

This section builds on the foundational concepts covered above with additional technical depth, edge cases, and configuration nuances that separate competent engineers from experts. When working on production ECU projects, the details covered here are the ones most commonly responsible for integration delays and late-phase defects.

Key principles to reinforce:

Configuration over coding: In AUTOSAR and automotive middleware environments, correctness is largely determined by ARXML configuration, not application code. A correctly implemented algorithm can produce wrong results due to a single misconfigured parameter.
Traceability as a first-class concern: Every configuration decision should be traceable to a requirement, safety goal, or architecture decision. Undocumented configuration choices are a common source of regression defects when ECUs are updated.
Cross-module dependencies: In tightly integrated automotive software stacks, changing one module's configuration often requires corresponding updates in dependent modules. Always perform a dependency impact analysis before submitting configuration changes.

🏭 How This Topic Appears in Production Projects

Project integration phase: The concepts covered in this lesson are most commonly encountered during ECU integration testing — when multiple software components from different teams are combined for the first time. Issues that were invisible in unit tests frequently surface at this stage.
Supplier/OEM interface: This is a topic that frequently appears in technical discussions between Tier-1 ECU suppliers and OEM system integrators. Engineers who can speak fluently about these details earn credibility and are often brought into critical design review meetings.
Automotive tool ecosystem: Vector CANoe/CANalyzer, dSPACE tools, and ETAS INCA are the standard tools used to validate and measure the correct behaviour of the systems described in this lesson. Familiarity with these tools alongside the conceptual knowledge dramatically accelerates debugging in real projects.

⚠️ Common Mistakes and How to Avoid Them

Assuming default configuration is correct: Automotive software tools ship with default configurations that are designed to compile and link, not to meet project-specific requirements. Every configuration parameter needs to be consciously set. 'It compiled' is not the same as 'it is correctly configured'.
Skipping documentation of configuration rationale: In a 3-year ECU project with team turnover, undocumented configuration choices become tribal knowledge that disappears when engineers leave. Document why a parameter is set to a specific value, not just what it is set to.
Testing only the happy path: Automotive ECUs must behave correctly under fault conditions, voltage variations, and communication errors. Always test the error handling paths as rigorously as the nominal operation. Many production escapes originate in untested error branches.
Version mismatches between teams: In a multi-team project, the BSW team, SWC team, and system integration team may use different versions of the same ARXML file. Version management of all ARXML files in a shared repository is mandatory, not optional.

📊 Industry Note

Engineers who master both the theoretical concepts and the practical toolchain skills covered in this course are among the most sought-after professionals in the automotive software industry. The combination of AUTOSAR standards knowledge, safety engineering understanding, and hands-on configuration experience commands premium salaries at OEMs and Tier-1 suppliers globally.