# Traceability Matrix: Software Requirements to Software Features

**Document ID:** TM-SWR-FEAT  
**Version:** 1.0  
**Date:** 2025-02-01  

## 1. Purpose

This document provides a comprehensive traceability matrix mapping software requirements to the software features that define them. This ensures that every software requirement is covered by a software feature and that feature scope is clearly defined.

## 2. Traceability Matrix

| Software Requirement ID | Requirement Description | Software Feature | System Feature Mapping |
|-------------------------|------------------------|------------------|------------------------|
| **Sensor Data Acquisition Requirements** |
| SWR-DAQ-001 | System shall support multi-sensor data acquisition | SF-DAQ | F-DAQ-01 |
| SWR-DAQ-002 | System shall provide sensor driver abstraction | SF-DAQ | F-DAQ-01 |
| SWR-DAQ-003 | System shall acquire data only from detected sensors | SF-DAQ | F-DAQ-01 |
| SWR-DAQ-004 | System shall perform high-frequency sampling | SF-DAQ | F-DAQ-02 |
| SWR-DAQ-005 | System shall apply local filtering to sensor data | SF-DAQ | F-DAQ-02 |
| SWR-DAQ-006 | System shall support configurable sampling parameters | SF-DAQ | F-DAQ-02 |
| SWR-DAQ-007 | System shall associate timestamps with sensor data | SF-DAQ | F-DAQ-03 |
| SWR-DAQ-008 | System shall generate timestamps after filtering | SF-DAQ | F-DAQ-03 |
| SWR-DAQ-009 | System shall create structured sensor data records | SF-DAQ | F-DAQ-03 |
| SWR-DAQ-010 | System shall complete acquisition within 100ms per sensor | SF-DAQ | F-DAQ-02 |
| SWR-DAQ-011 | System shall track sensor operational states | SF-DAQ | F-DAQ-04 |
| SWR-DAQ-012 | System shall include validity flags with sensor data | SF-DAQ | F-DAQ-04 |
| SWR-DAQ-013 | System shall enforce sensor warmup periods | SF-DAQ | F-DAQ-04 |
| **Communication Requirements** |
| SWR-COM-001 | System shall support MQTT over TLS communication | SF-COM | F-COM-01 |
| SWR-COM-002 | System shall transmit sensor data to Main Hub | SF-COM | F-COM-01 |
| SWR-COM-003 | System shall receive commands from Main Hub | SF-COM | F-COM-01 |
| SWR-COM-004 | System shall monitor communication link status | SF-COM | F-COM-01 |
| SWR-COM-005 | System shall support on-demand data requests | SF-COM | F-COM-02 |
| SWR-COM-006 | System shall respond within 100ms to data requests | SF-COM | F-COM-02 |
| SWR-COM-007 | System shall include validity info in responses | SF-COM | F-COM-02 |
| SWR-COM-008 | System shall support ESP-NOW peer communication | SF-COM | F-COM-03 |
| SWR-COM-009 | System shall support peer coordination functions | SF-COM | F-COM-03 |
| SWR-COM-010 | System shall isolate peer from main hub communication | SF-COM | F-COM-03 |
| SWR-COM-011 | System shall implement heartbeat mechanism | SF-COM | F-COM-01 |
| SWR-COM-012 | System shall use CBOR encoding for payloads | SF-COM | F-COM-01 |
| SWR-COM-013 | System shall support automatic reconnection | SF-COM | F-COM-01 |
| SWR-COM-014 | System shall encrypt ESP-NOW peer communication | SF-COM | F-COM-03 |
| SWR-COM-015 | System shall implement ESP-NOW acknowledgment | SF-COM | F-COM-03 |
| SWR-COM-016 | System shall support long-range fallback communication | SF-COM | F-COM-04 |
| SWR-COM-017 | System shall use fallback for emergency/backup only | SF-COM | F-COM-04 |
| **Data Persistence Requirements** |
| SWR-DATA-001 | System shall persist sensor data in non-volatile storage | SF-DATA | F-DATA-01 |
| SWR-DATA-002 | System shall store sensor data with metadata | SF-DATA | F-DATA-01 |
| SWR-DATA-003 | System shall support configurable retention policies | SF-DATA | F-DATA-01 |
| SWR-DATA-004 | System shall provide DP component as storage interface | SF-DATA | F-DATA-02 |
| SWR-DATA-005 | System shall prevent direct storage hardware access | SF-DATA | F-DATA-02 |
| SWR-DATA-006 | System shall support data serialization | SF-DATA | F-DATA-02 |
| SWR-DATA-007 | System shall flush data before state transitions | SF-DATA | F-DATA-03 |
| SWR-DATA-008 | System shall protect data integrity during updates | SF-DATA | F-DATA-03 |
| SWR-DATA-009 | System shall verify data persistence success | SF-DATA | F-DATA-03 |
| SWR-DATA-010 | System shall detect brownout conditions | SF-DATA | F-DATA-04 |
| SWR-DATA-011 | System shall flush critical data on brownout | SF-DATA | F-DATA-04 |
| SWR-DATA-012 | System shall complete emergency flush within 1-2s | SF-DATA | F-DATA-04 |
| SWR-DATA-013 | System shall implement wear-aware writing | SF-DATA | F-DATA-04 |
| **Diagnostics Requirements** |
| SWR-DIAG-001 | System shall implement diagnostic code framework | SF-DIAG | F-DIAG-01 |
| SWR-DIAG-002 | System shall assign unique diagnostic codes | SF-DIAG | F-DIAG-01 |
| SWR-DIAG-003 | System shall classify diagnostics by severity | SF-DIAG | F-DIAG-01 |
| SWR-DIAG-004 | System shall timestamp diagnostic events | SF-DIAG | F-DIAG-01 |
| SWR-DIAG-005 | System shall persist diagnostic events | SF-DIAG | F-DIAG-02 |
| SWR-DIAG-006 | System shall retain diagnostics across resets | SF-DIAG | F-DIAG-02 |
| SWR-DIAG-007 | System shall implement bounded diagnostic storage | SF-DIAG | F-DIAG-02 |
| SWR-DIAG-008 | System shall provide diagnostic session interface | SF-DIAG | F-DIAG-03 |
| SWR-DIAG-009 | System shall allow diagnostic data retrieval | SF-DIAG | F-DIAG-03 |
| SWR-DIAG-010 | System shall allow diagnostic record clearing | SF-DIAG | F-DIAG-03 |
| SWR-DIAG-011 | System shall not interfere with normal operations | SF-DIAG | F-DIAG-03 |
| SWR-DIAG-012 | System shall implement Task Watchdog | SF-DIAG | F-DIAG-04 |
| SWR-DIAG-013 | System shall implement Interrupt Watchdog | SF-DIAG | F-DIAG-04 |
| SWR-DIAG-014 | System shall implement RTC Watchdog | SF-DIAG | F-DIAG-04 |
| **System Management Requirements** |
| SWR-SYS-001 | System shall implement finite state machine | SF-SYS | F-SYS-01 |
| SWR-SYS-002 | System shall restrict operations by state | SF-SYS | F-SYS-01 |
| SWR-SYS-003 | System shall notify components of state changes | SF-SYS | F-SYS-01 |
| SWR-SYS-004 | System shall execute controlled teardown | SF-SYS | F-SYS-02 |
| SWR-SYS-005 | System shall persist critical data before teardown | SF-SYS | F-SYS-02 |
| SWR-SYS-006 | System shall prevent data corruption during teardown | SF-SYS | F-SYS-02 |
| SWR-SYS-007 | System shall provide OLED display interface | SF-SYS | F-SYS-03 |
| SWR-SYS-008 | System shall display system status information | SF-SYS | F-SYS-03 |
| SWR-SYS-009 | System shall provide button navigation | SF-SYS | F-SYS-03 |
| SWR-SYS-010 | System shall provide menu-based information access | SF-SYS | F-SYS-03 |
| SWR-SYS-011 | System shall support diagnostic sessions | SF-SYS | F-SYS-04 |
| SWR-SYS-012 | System shall support debug sessions | SF-SYS | F-SYS-04 |
| SWR-SYS-013 | System shall restrict debug access to authorized users | SF-SYS | F-SYS-04 |
| SWR-SYS-014 | System shall enforce GPIO discipline | SF-SYS | F-SYS-05 |
| SWR-SYS-015 | System shall ensure I2C pull-up resistors | SF-SYS | F-SYS-05 |
| SWR-SYS-016 | System shall use ADC1 when Wi-Fi active | SF-SYS | F-SYS-05 |
| SWR-SYS-017 | System shall maintain GPIO map documentation | SF-SYS | F-SYS-05 |
| **Data Quality & Calibration Requirements** |
| SWR-DQC-001 | System shall detect sensor presence | SF-DQC | F-DQC-01 |
| SWR-DQC-002 | System shall perform detection during startup | SF-DQC | F-DQC-01 |
| SWR-DQC-003 | System shall initialize only detected sensors | SF-DQC | F-DQC-01 |
| SWR-DQC-004 | System shall assign sensors to predefined slots | SF-DQC | F-DQC-02 |
| SWR-DQC-005 | System shall verify sensor-slot compatibility | SF-DQC | F-DQC-02 |
| SWR-DQC-006 | System shall report sensor-slot mismatches | SF-DQC | F-DQC-02 |
| SWR-DQC-007 | System shall monitor sensor responsiveness | SF-DQC | F-DQC-03 |
| SWR-DQC-008 | System shall detect sensor failures | SF-DQC | F-DQC-03 |
| SWR-DQC-009 | System shall exclude failed sensors from reporting | SF-DQC | F-DQC-03 |
| SWR-DQC-010 | System shall report sensor failures to Main Hub | SF-DQC | F-DQC-03 |
| SWR-DQC-011 | System shall maintain Machine Constants dataset | SF-DQC | F-DQC-04 |
| SWR-DQC-012 | System shall persist Machine Constants | SF-DQC | F-DQC-04 |
| SWR-DQC-013 | System shall load Machine Constants at startup | SF-DQC | F-DQC-04 |
| SWR-DQC-014 | System shall support remote MC updates | SF-DQC | F-DQC-04 |
| SWR-DQC-015 | System shall apply MC updates via teardown | SF-DQC | F-DQC-04 |
| SWR-DQC-016 | System shall support redundant sensors | SF-DQC | F-DQC-05 |
| SWR-DQC-017 | System shall implement sensor fusion | SF-DQC | F-DQC-05 |
| SWR-DQC-018 | System shall ensure critical parameter redundancy | SF-DQC | F-DQC-05 |
| **OTA Requirements** |
| SWR-OTA-001 | System shall support OTA update negotiation | SF-OTA | F-OTA-01 |
| SWR-OTA-002 | System shall verify readiness before OTA | SF-OTA | F-OTA-01 |
| SWR-OTA-003 | System shall acknowledge/reject OTA requests | SF-OTA | F-OTA-01 |
| SWR-OTA-004 | System shall receive firmware over secure channel | SF-OTA | F-OTA-02 |
| SWR-OTA-005 | System shall store firmware before validation | SF-OTA | F-OTA-02 |
| SWR-OTA-006 | System shall prevent active firmware overwrite | SF-OTA | F-OTA-02 |
| SWR-OTA-007 | System shall validate firmware integrity | SF-OTA | F-OTA-03 |
| SWR-OTA-008 | System shall reject invalid firmware | SF-OTA | F-OTA-03 |
| SWR-OTA-009 | System shall report validation results | SF-OTA | F-OTA-03 |
| SWR-OTA-010 | System shall execute teardown before activation | SF-OTA | F-OTA-04 |
| SWR-OTA-011 | System shall persist critical data before flashing | SF-OTA | F-OTA-04 |
| SWR-OTA-012 | System shall activate only validated firmware | SF-OTA | F-OTA-04 |
| SWR-OTA-013 | System shall reboot into new firmware | SF-OTA | F-OTA-04 |
| SWR-OTA-014 | System shall implement A/B partitioning | SF-OTA | F-OTA-05 |
| SWR-OTA-015 | System shall support automatic rollback | SF-OTA | F-OTA-05 |
| SWR-OTA-016 | System shall report rollback events | SF-OTA | F-OTA-05 |
| **Security Requirements** |
| SWR-SEC-001 | System shall verify firmware authenticity at boot | SF-SEC | F-SEC-01 |
| SWR-SEC-002 | System shall prevent execution of invalid firmware | SF-SEC | F-SEC-01 |
| SWR-SEC-003 | System shall enter boot failure state on violation | SF-SEC | F-SEC-01 |
| SWR-SEC-004 | System shall protect root-of-trust | SF-SEC | F-SEC-01 |
| SWR-SEC-005 | System shall encrypt sensitive flash data | SF-SEC | F-SEC-02 |
| SWR-SEC-006 | System shall support external storage encryption | SF-SEC | F-SEC-02 |
| SWR-SEC-007 | System shall restrict cryptographic key access | SF-SEC | F-SEC-02 |
| SWR-SEC-008 | System shall ensure stored data integrity | SF-SEC | F-SEC-02 |
| SWR-SEC-009 | System shall encrypt all Main Hub communication | SF-SEC | F-SEC-03 |
| SWR-SEC-010 | System shall ensure message integrity/authenticity | SF-SEC | F-SEC-03 |
| SWR-SEC-011 | System shall use secure channels for OTA | SF-SEC | F-SEC-03 |
| SWR-SEC-012 | System shall detect communication security violations | SF-SEC | F-SEC-03 |
| SWR-SEC-013 | System shall report security violations as FATAL | SF-SEC | F-SEC-04 |
| SWR-SEC-014 | System shall implement eFuse anti-rollback | SF-SEC | F-SEC-04 |
| SWR-SEC-015 | System shall protect keys during power loss | SF-SEC | F-SEC-04 |

## 3. Feature Coverage Analysis

### 3.1 Software Feature to Requirement Count

| Software Feature | Requirement Count | System Features Covered |
|------------------|------------------|------------------------|
| SF-DAQ | 13 | F-DAQ-01, F-DAQ-02, F-DAQ-03, F-DAQ-04 |
| SF-COM | 17 | F-COM-01, F-COM-02, F-COM-03, F-COM-04 |
| SF-DATA | 13 | F-DATA-01, F-DATA-02, F-DATA-03, F-DATA-04 |
| SF-DIAG | 14 | F-DIAG-01, F-DIAG-02, F-DIAG-03, F-DIAG-04 |
| SF-SYS | 17 | F-SYS-01, F-SYS-02, F-SYS-03, F-SYS-04, F-SYS-05 |
| SF-DQC | 18 | F-DQC-01, F-DQC-02, F-DQC-03, F-DQC-04, F-DQC-05 |
| SF-OTA | 16 | F-OTA-01, F-OTA-02, F-OTA-03, F-OTA-04, F-OTA-05 |
| SF-SEC | 15 | F-SEC-01, F-SEC-02, F-SEC-03, F-SEC-04 |

### 3.2 System Feature to Software Feature Mapping

| System Feature | Software Feature | Requirement Count |
|----------------|------------------|------------------|
| F-DAQ-01 | SF-DAQ | 3 |
| F-DAQ-02 | SF-DAQ | 4 |
| F-DAQ-03 | SF-DAQ | 3 |
| F-DAQ-04 | SF-DAQ | 3 |
| F-COM-01 | SF-COM | 7 |
| F-COM-02 | SF-COM | 3 |
| F-COM-03 | SF-COM | 5 |
| F-COM-04 | SF-COM | 2 |
| F-DATA-01 | SF-DATA | 3 |
| F-DATA-02 | SF-DATA | 3 |
| F-DATA-03 | SF-DATA | 3 |
| F-DATA-04 | SF-DATA | 4 |
| F-DIAG-01 | SF-DIAG | 4 |
| F-DIAG-02 | SF-DIAG | 3 |
| F-DIAG-03 | SF-DIAG | 4 |
| F-DIAG-04 | SF-DIAG | 3 |
| F-SYS-01 | SF-SYS | 3 |
| F-SYS-02 | SF-SYS | 3 |
| F-SYS-03 | SF-SYS | 4 |
| F-SYS-04 | SF-SYS | 3 |
| F-SYS-05 | SF-SYS | 4 |
| F-DQC-01 | SF-DQC | 3 |
| F-DQC-02 | SF-DQC | 3 |
| F-DQC-03 | SF-DQC | 4 |
| F-DQC-04 | SF-DQC | 5 |
| F-DQC-05 | SF-DQC | 3 |
| F-OTA-01 | SF-OTA | 3 |
| F-OTA-02 | SF-OTA | 3 |
| F-OTA-03 | SF-OTA | 3 |
| F-OTA-04 | SF-OTA | 4 |
| F-OTA-05 | SF-OTA | 3 |
| F-SEC-01 | SF-SEC | 4 |
| F-SEC-02 | SF-SEC | 4 |
| F-SEC-03 | SF-SEC | 4 |
| F-SEC-04 | SF-SEC | 3 |

## 4. Completeness Analysis

### 4.1 Feature Coverage Completeness
- **Total System Features**: 32
- **Total Software Features**: 8
- **Coverage Ratio**: 1:4 (Each software feature covers 4 system features on average)

### 4.2 Requirement Distribution
- **Total Software Requirements**: 123
- **Average Requirements per Software Feature**: 15.4
- **Most Complex Feature**: SF-DQC (18 requirements)
- **Least Complex Feature**: SF-DAQ (13 requirements)

## 5. Cross-Feature Dependencies

### 5.1 High Interdependency Features
- **SF-DATA**: Required by SF-DAQ, SF-DIAG, SF-DQC, SF-OTA
- **SF-SYS**: Provides state management for SF-OTA, SF-DQC
- **SF-SEC**: Provides security foundation for SF-COM, SF-OTA
- **SF-DIAG**: Receives events from all other features

### 5.2 Independent Features
- **SF-DAQ**: Primary data source, minimal dependencies
- **SF-COM**: Primarily dependent on SF-DATA for data access

## 6. Validation Results

### 6.1 Orphan Analysis
- **Requirements without Features**: None identified
- **Features without Requirements**: None identified
- **System Features without Software Features**: None identified

### 6.2 Consistency Check
- All software requirements are mapped to exactly one software feature
- All software features map to one or more system features
- No circular dependencies identified in feature relationships

## 7. Notes

1. The 1:1 mapping between software requirements and software features ensures clear responsibility assignment
2. Software features provide a logical grouping of related requirements
3. Cross-feature dependencies are managed through well-defined interfaces
4. The traceability supports both forward and backward tracing from system to software requirements