system_design/
├── features/                          # Feature specifications
│   ├── Features.md                    # Main feature catalog
│   ├── [DAQ] Sensor Data Acquisition Features.md
│   ├── [DQC] Data Quality & Calibration Features.md
│   ├── [COM] Communication Features.md
│   ├── [DIAG] Diagnostics & Health Monitoring Features.md
│   ├── [DATA] Persistence & Data Management Features.md
│   ├── [OTA] Firmware Update (OTA) Features.md
│   ├── [SEC] Security & Safety Features.md
│   ├── [SYS] System Management Features.md
│   ├── [PWR] Power & Fault Handling Features.md
│   ├── [HW] Hardware Abstraction Features.md
│   ├── Cross-Feature Constraints.md
│   ├── System Assumptions & Limitations.md
│   └── System_Requirements_Traceability.csv  # Feature → SR mapping
│
├── specifications/                    # System specifications
│   ├── System_State_Machine_Specification.md
│   ├── Failure_Handling_Model.md
│   └── System Review Checklist.md
│
├── SRS/                              # Software Requirements Specification
│   ├── SRS.md                        # Main SRS document
│   ├── Annex_A_Traceability.md
│   ├── Annex_B_Interfaces.md
│   ├── Annex_C_Budgets.md
│   ├── VV_Matrix.md                  # Verification & Validation matrix
│   └── Traceability_SWRS.csv         # SWR traceability
│
├── analysis/                         # Analysis and review documents
│   ├── Gap_Analysis_and_Solutions.md
│   └── Engineering_Review_Report.md
│
├── system_requirementsand_and_traceability.csv  # Original system requirements
└── README.md                         # This file

Document Overview

Features (`features/`)

Contains all feature specifications with system requirements:

10 feature groups (DAQ, DQC, COM, DIAG, DATA, OTA, SEC, SYS, PWR, HW)
39 features total
139 system requirements (SR-*)
System_Requirements_Traceability.csv - Complete feature-to-requirement mapping

Specifications (`specifications/`)

Core system specifications:

System State Machine - 11 states with transition rules
Failure Handling Model - Fault taxonomy and recovery behaviors
System Review Checklist - Gate criteria for implementation

SRS (`SRS/`)

Software Requirements Specification (ISO/IEC/IEEE 29148 compliant):

Main SRS - Over 200 Software Requirements (SWR-*)
Annexes - Traceability, Interfaces, Budgets
V&V Matrix - Verification methods for all requirements

Analysis (`analysis/`)

Analysis and review documents:

Gap Analysis and Solutions - Consolidated gap analysis with solutions
Engineering Review Report - Architecture review findings

Quick Reference

Feature Groups

Group	Features	System Requirements
DAQ	4	13
DQC	5	18
COM	4	17
DIAG	4	14
DATA	4	13
OTA	5	16
SEC	4	15
SYS	5	17
PWR	2	8
HW	2	8
TOTAL	39	139

System States

INIT - Hardware and software initialization
BOOT_FAILURE - Secure boot verification failed
RUNNING - Normal sensor acquisition and communication
WARNING - Non-fatal fault detected, degraded operation
FAULT - Fatal error, core functionality disabled
OTA_PREP - OTA preparation phase
OTA_UPDATE - Firmware update in progress
MC_UPDATE - Machine constants update in progress
TEARDOWN - Controlled shutdown sequence
SERVICE - Engineering or diagnostic interaction
SD_DEGRADED - SD card failure detected, fallback mode

Technology Stack

Hardware: ESP32-S3
Framework: ESP-IDF v5.4
Communication: Wi-Fi 802.11n, MQTT over TLS 1.2, ESP-NOW
Security: Secure Boot V2, Flash Encryption (AES-256), mTLS
Storage: FAT32 (SD Card), NVS (Encrypted)
OTA: A/B Partitioning, SHA-256

Document Status

Status: Final for Implementation Phase
Next Phase: Component Design → Implementation

For questions or updates, refer to the individual feature specifications or system specifications.

README.md

ASF Sensor Hub - System Design Documentation

Directory Structure