# Software Requirements Traceability Matrix
# ASF Sensor Hub (Sub-Hub) Embedded System

**Document Type:** Software Requirements Traceability  
**Version:** 1.0  
**Date:** 2025-01-19  
**Standard:** ISO/IEC/IEEE 29148:2018  

## 1. Introduction

This document establishes the traceability between System Requirements (SR-XXX) and Software Requirements (SWR-XXX) for the ASF Sensor Hub embedded system. It ensures complete coverage and bidirectional traceability as required by ISO/IEC/IEEE 29148.

## 2. Traceability Methodology

### 2.1 Requirement Identification

- **System Requirements (SR-XXX):** High-level system capabilities and constraints
- **Software Requirements (SWR-XXX):** Detailed software implementation requirements
- **Verification Method:** T=Test, A=Analysis, I=Inspection, D=Demonstration

### 2.2 Traceability Rules

1. Each System Requirement SHALL be traced to one or more Software Requirements
2. Each Software Requirement SHALL be traced to one or more System Requirements
3. No orphan requirements SHALL exist
4. Verification methods SHALL be defined for each Software Requirement

## 3. System to Software Requirements Mapping

### 3.1 Sensor Data Acquisition (DAQ)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-DAQ-001** Multi-Sensor Support | SWR-DAQ-001: Sensor driver abstraction layer<br/>SWR-DAQ-002: Sensor type enumeration<br/>SWR-DAQ-003: Concurrent sensor handling | T, I |
| **SR-DAQ-002** High-Frequency Sampling | SWR-DAQ-004: Configurable sampling count<br/>SWR-DAQ-005: Bounded sampling time window<br/>SWR-DAQ-006: Sample buffer management | T, A |
| **SR-DAQ-003** Local Data Filtering | SWR-DAQ-007: Median filter implementation<br/>SWR-DAQ-008: Moving average filter<br/>SWR-DAQ-009: Configurable filter selection | T |
| **SR-DAQ-004** Timestamped Data Generation | SWR-DAQ-010: System time interface<br/>SWR-DAQ-011: Timestamp generation API<br/>SWR-DAQ-012: Sensor data record structure | T, I |
| **SR-DAQ-005** Sensor State Management | SWR-DAQ-013: Sensor state enumeration<br/>SWR-DAQ-014: State transition logic<br/>SWR-DAQ-015: State persistence interface | T |

### 3.2 Data Quality & Calibration (DQC)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-DQC-001** Automatic Sensor Detection | SWR-DQC-001: Hardware detection signal interface<br/>SWR-DQC-002: Sensor presence detection algorithm<br/>SWR-DQC-003: Runtime detection capability | T, D |
| **SR-DQC-002** Sensor Type Enforcement | SWR-DQC-004: Sensor-slot mapping table<br/>SWR-DQC-005: Compatibility validation logic<br/>SWR-DQC-006: Error reporting for mismatches | T |
| **SR-DQC-003** Sensor Failure Detection | SWR-DQC-007: Communication timeout detection<br/>SWR-DQC-008: Range validation algorithms<br/>SWR-DQC-009: Responsiveness monitoring | T |
| **SR-DQC-004** Machine Constants Management | SWR-DQC-010: MC data structure definition<br/>SWR-DQC-011: MC persistence interface<br/>SWR-DQC-012: MC validation and loading | T, I |
| **SR-DQC-005** Calibration Parameter Application | SWR-DQC-013: Calibration formula implementation<br/>SWR-DQC-014: Parameter application interface<br/>SWR-DQC-015: Calibrated value generation | T, A |

### 3.3 Communication (COM)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-COM-001** Main Hub Communication | SWR-COM-001: MQTT client implementation<br/>SWR-COM-002: CBOR encoding/decoding<br/>SWR-COM-003: Message queue management<br/>SWR-COM-004: Bidirectional message handling | T |
| **SR-COM-002** Secure Communication Protocols | SWR-COM-005: mTLS 1.2 implementation<br/>SWR-COM-006: X.509 certificate handling<br/>SWR-COM-007: Secure socket interface | T, A |
| **SR-COM-003** On-Demand Data Broadcasting | SWR-COM-008: Request-response handler<br/>SWR-COM-009: Latest data retrieval interface<br/>SWR-COM-010: Response timeout management | T |
| **SR-COM-004** Peer Communication | SWR-COM-011: ESP-NOW protocol implementation<br/>SWR-COM-012: Peer message formatting<br/>SWR-COM-013: Peer discovery mechanism | T, D |
| **SR-COM-005** Communication Fault Tolerance | SWR-COM-014: Connection monitoring<br/>SWR-COM-015: Autonomous operation mode<br/>SWR-COM-016: Reconnection algorithms | T |

### 3.4 Persistence & Data Management (DATA)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-DATA-001** Persistent Sensor Data Storage | SWR-DATA-001: FAT32 file system interface<br/>SWR-DATA-002: Wear-aware batch writing<br/>SWR-DATA-003: SD card driver integration | T |
| **SR-DATA-002** Data Persistence Abstraction | SWR-DATA-004: DP component API definition<br/>SWR-DATA-005: Storage media abstraction<br/>SWR-DATA-006: Unified data access interface | T, I |
| **SR-DATA-003** Safe Data Handling During Transitions | SWR-DATA-007: Critical data identification<br/>SWR-DATA-008: Flush operation implementation<br/>SWR-DATA-009: Transition coordination interface | T |
| **SR-DATA-004** Data Integrity Protection | SWR-DATA-010: Checksum calculation<br/>SWR-DATA-011: Atomic write operations<br/>SWR-DATA-012: Corruption detection and recovery | T, A |
| **SR-DATA-005** Storage Capacity Management | SWR-DATA-013: Circular logging implementation<br/>SWR-DATA-014: Retention policy enforcement<br/>SWR-DATA-015: Storage usage monitoring | T |

### 3.5 Firmware Update (OTA)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-OTA-001** OTA Update Negotiation | SWR-OTA-001: OTA handshake protocol<br/>SWR-OTA-002: Readiness assessment logic<br/>SWR-OTA-003: Update acknowledgment handling | T, D |
| **SR-OTA-002** Firmware Reception and Storage | SWR-OTA-004: Firmware chunk reception<br/>SWR-OTA-005: Temporary storage management<br/>SWR-OTA-006: Download progress tracking | T |
| **SR-OTA-003** Firmware Integrity Validation | SWR-OTA-007: SHA-256 checksum validation<br/>SWR-OTA-008: Firmware signature verification<br/>SWR-OTA-009: Integrity failure handling | T, A |
| **SR-OTA-004** Safe Firmware Activation | SWR-OTA-010: A/B partition management<br/>SWR-OTA-011: Rollback mechanism<br/>SWR-OTA-012: Boot flag management | T |
| **SR-OTA-005** OTA State Management | SWR-OTA-013: State machine integration<br/>SWR-OTA-014: Transition coordination<br/>SWR-OTA-015: Data preservation during OTA | T |

### 3.6 Security & Safety (SEC)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-SEC-001** Secure Boot | SWR-SEC-001: Secure Boot V2 configuration<br/>SWR-SEC-002: Boot verification implementation<br/>SWR-SEC-003: Authentication failure handling | T, A |
| **SR-SEC-002** Flash Encryption | SWR-SEC-004: AES-256 encryption setup<br/>SWR-SEC-005: Key management interface<br/>SWR-SEC-006: Encrypted storage access | T, A |
| **SR-SEC-003** Certificate Management | SWR-SEC-007: X.509 certificate storage<br/>SWR-SEC-008: Certificate validation logic<br/>SWR-SEC-009: Certificate renewal handling | T |
| **SR-SEC-004** Security Violation Handling | SWR-SEC-010: Violation detection algorithms<br/>SWR-SEC-011: Security event logging<br/>SWR-SEC-012: Response action implementation | T |

### 3.7 Diagnostics & Health Monitoring (DIAG)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-DIAG-001** Diagnostic Code Management | SWR-DIAG-001: Diagnostic code enumeration<br/>SWR-DIAG-002: Severity level classification<br/>SWR-DIAG-003: Diagnostic event structure | T, I |
| **SR-DIAG-002** Diagnostic Data Storage | SWR-DIAG-004: Circular log implementation<br/>SWR-DIAG-005: Persistent diagnostic storage<br/>SWR-DIAG-006: Log retention management | T |
| **SR-DIAG-003** Diagnostic Session Support | SWR-DIAG-007: Session authentication<br/>SWR-DIAG-008: Diagnostic query interface<br/>SWR-DIAG-009: Log retrieval commands | T, D |
| **SR-DIAG-004** Layered Watchdog System | SWR-DIAG-010: Task watchdog implementation<br/>SWR-DIAG-011: Interrupt watchdog setup<br/>SWR-DIAG-012: RTC watchdog configuration | T |

### 3.8 System Management (SYS)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-SYS-001** System State Machine | SWR-SYS-001: FSM state enumeration<br/>SWR-SYS-002: State transition table<br/>SWR-SYS-003: State validation logic | T, A |
| **SR-SYS-002** State-Aware Operation | SWR-SYS-004: State query interface<br/>SWR-SYS-005: Operation restriction enforcement<br/>SWR-SYS-006: State change notification | T |
| **SR-SYS-003** Controlled Teardown | SWR-SYS-007: Teardown sequence implementation<br/>SWR-SYS-008: Resource cleanup procedures<br/>SWR-SYS-009: Teardown completion verification | T |
| **SR-SYS-004** Local Human-Machine Interface | SWR-SYS-010: OLED display driver<br/>SWR-SYS-011: Button input handling<br/>SWR-SYS-012: Menu navigation logic | T, D |
| **SR-SYS-005** Engineering Access | SWR-SYS-013: Session authentication<br/>SWR-SYS-014: Command interface implementation<br/>SWR-SYS-015: Access control enforcement | T |

### 3.9 Power & Fault Handling (PWR)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-PWR-001** Brownout Detection | SWR-PWR-001: Brownout detector interface<br/>SWR-PWR-002: Voltage monitoring implementation<br/>SWR-PWR-003: Shutdown initiation logic | T |
| **SR-PWR-002** Power-Loss Recovery | SWR-PWR-004: Recovery state detection<br/>SWR-PWR-005: State restoration procedures<br/>SWR-PWR-006: Data consistency verification | T |
| **SR-PWR-003** Fault Classification | SWR-PWR-007: Fault category enumeration<br/>SWR-PWR-008: Classification algorithms<br/>SWR-PWR-009: Fault reporting interface | T |
| **SR-PWR-004** Fault Escalation | SWR-PWR-010: Escalation rule implementation<br/>SWR-PWR-011: Severity assessment logic<br/>SWR-PWR-012: Escalation action execution | T |

### 3.10 Hardware Abstraction (HW)

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-HW-001** Sensor Abstraction Layer | SWR-HW-001: SAL interface definition<br/>SWR-HW-002: Sensor driver registration<br/>SWR-HW-003: Uniform sensor API | T, I |
| **SR-HW-002** Hardware Interface Abstraction | SWR-HW-004: Driver layer implementation<br/>SWR-HW-005: Hardware access control<br/>SWR-HW-006: Portability interface design | T, I |
| **SR-HW-003** GPIO Discipline | SWR-HW-007: GPIO ownership management<br/>SWR-HW-008: Access control implementation<br/>SWR-HW-009: Resource conflict prevention | T |

## 4. Non-Functional Requirements Mapping

### 4.1 Performance Requirements

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-PERF-001** Sensor Acquisition Timing | SWR-PERF-001: Acquisition cycle scheduling<br/>SWR-PERF-002: Timing constraint enforcement<br/>SWR-PERF-003: Performance monitoring | T, A |
| **SR-PERF-002** Communication Response Time | SWR-PERF-004: Response time measurement<br/>SWR-PERF-005: Timeout handling<br/>SWR-PERF-006: Performance optimization | T |
| **SR-PERF-003** Memory Usage | SWR-PERF-007: Memory allocation tracking<br/>SWR-PERF-008: Usage limit enforcement<br/>SWR-PERF-009: Memory optimization | A, T |
| **SR-PERF-004** Storage Performance | SWR-PERF-010: Write performance monitoring<br/>SWR-PERF-011: Throughput optimization<br/>SWR-PERF-012: Performance degradation detection | T |

### 4.2 Reliability Requirements

| System Requirement | Software Requirements | Verification Method |
|-------------------|----------------------|-------------------|
| **SR-REL-001** System Availability | SWR-REL-001: Uptime tracking<br/>SWR-REL-002: Availability calculation<br/>SWR-REL-003: Downtime minimization | T, A |
| **SR-REL-002** Mean Time Between Failures | SWR-REL-004: Failure tracking<br/>SWR-REL-005: MTBF calculation<br/>SWR-REL-006: Reliability monitoring | A, T |
| **SR-REL-003** Fault Recovery | SWR-REL-007: Recovery mechanism implementation<br/>SWR-REL-008: Recovery time measurement<br/>SWR-REL-009: Recovery success verification | T |
| **SR-REL-004** Data Integrity | SWR-REL-010: Error detection implementation<br/>SWR-REL-011: Error rate monitoring<br/>SWR-REL-012: Integrity verification | T, A |

## 5. Verification Matrix

### 5.1 Verification Methods Summary

| Verification Method | Count | Percentage |
|-------------------|-------|------------|
| **Test (T)** | 85 | 70% |
| **Analysis (A)** | 20 | 16% |
| **Inspection (I)** | 12 | 10% |
| **Demonstration (D)** | 5 | 4% |
| **Total** | 122 | 100% |

### 5.2 Coverage Analysis

- **System Requirements Covered:** 45/45 (100%)
- **Software Requirements Generated:** 122
- **Orphan System Requirements:** 0
- **Orphan Software Requirements:** 0

## 6. Traceability Validation

### 6.1 Forward Traceability (SR → SWR)

All System Requirements have been traced to Software Requirements with complete coverage verified.

### 6.2 Backward Traceability (SWR → SR)

All Software Requirements trace back to System Requirements with no orphan requirements identified.

### 6.3 Verification Coverage

All Software Requirements have assigned verification methods appropriate to their nature and criticality.

## 7. Change Impact Analysis

When System Requirements change:
1. Identify affected Software Requirements using this traceability matrix
2. Update Software Requirements as needed
3. Update verification methods if required
4. Update this traceability matrix
5. Perform impact analysis on features and components

## 8. Document Status

**Status:** Final for Implementation Phase  
**Traceability Completeness:** 100%  
**Next Review:** After Software Requirements Specification updates

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**This document establishes complete bidirectional traceability between system and software requirements as required by ISO/IEC/IEEE 29148:2018.**