31 KiB
Software Requirements Specification (SRS)
Document ID: SRS-ASF-SensorHub-001
Version: 1.0
Date: 2025-01-19
Standard: ISO/IEC/IEEE 29148:2018
Scope: Sensor Hub (Sub-Hub) Software Requirements
1. Introduction
1.1 Purpose
This Software Requirements Specification (SRS) defines the software requirements for the ASF Sensor Hub (Sub-Hub) embedded system. This document provides a complete description of all software requirements, derived from system requirements and features, to enable implementation and verification.
1.2 Scope
This SRS covers:
- Sensor Hub firmware running on ESP32-S3
- All application-layer components and drivers
- Interfaces to Main Hub, sensors, and storage
- System state management, diagnostics, and security
This SRS explicitly excludes:
- Main Hub firmware
- Cloud services
- Hardware design specifications
- Manufacturing and deployment procedures
1.3 Definitions, Acronyms, and Abbreviations
| Term | Definition |
|---|---|
| DAQ | Data Acquisition |
| DQC | Data Quality & Calibration |
| DIAG | Diagnostics & Health Monitoring |
| DP | Data Persistence component |
| FSM | Finite State Machine |
| MC | Machine Constants |
| NVM | Non-Volatile Memory |
| OTA | Over-The-Air (firmware update) |
| SRS | Software Requirements Specification |
| SR | System Requirement |
| SWR | Software Requirement |
| SWRS | Software Requirements |
1.4 References
- ISO/IEC/IEEE 29148:2018 - Systems and software engineering - Life cycle processes - Requirements engineering
- System Requirements:
System Design/system_requirementsand_and_traceability.csv - Features:
System Design/Features/ - System State Machine:
System Design/System_State_Machine_Specification.md - Failure Handling Model:
System Design/Failure_Handling_Model.md - Cross-Feature Constraints:
System Design/Features/Cross-Feature Constraints.md
1.5 Overview
This SRS is organized as follows:
- Section 2: Overall Description (product perspective, functions, user characteristics, constraints)
- Section 3: Specific Requirements (functional, interface, performance, design constraints, quality attributes)
- Annex A: Software Requirements Traceability Matrix
- Annex B: External Interface Specifications
- Annex C: Timing and Resource Budgets
2. Overall Description
2.1 Product Perspective
The Sensor Hub is an embedded system component within the Distributed Intelligent Poultry Farm Environmental Control System (DIPFECS). It operates autonomously but communicates with a Main Hub for data transmission and configuration updates.
System Context:
[Sensors] → [Sensor Hub] ↔ [Main Hub] ↔ [Central Server]
↓
[SD Card / NVM]
2.2 Product Functions
The Sensor Hub software provides the following major functions:
- Sensor Data Acquisition (DAQ) - Multi-sensor sampling, filtering, timestamping
- Data Quality & Calibration (DQC) - Sensor detection, validation, calibration management
- Communication (COM) - Bidirectional communication with Main Hub and peer Sensor Hubs
- Diagnostics & Health Monitoring (DIAG) - Fault detection, classification, persistent logging
- Persistence & Data Management (DATA) - Non-volatile storage of sensor data and system state
- Firmware Update (OTA) - Secure over-the-air firmware updates
- Security & Safety (SEC) - Secure boot, encrypted storage, encrypted communication
- System Management (SYS) - State machine, teardown, HMI, debug sessions
2.3 User Characteristics
Primary Users:
- Farm Operators: Monitor system status via OLED display
- Engineers: Access diagnostic and debug sessions
- Main Hub: Automated data collection and control
User Assumptions:
- Farm operators have basic technical knowledge
- Engineers have embedded systems expertise
- Main Hub communication is automated
2.4 Constraints
2.4.1 Hardware Constraints
- ESP32-S3 microcontroller (dual-core, 512KB SRAM, 8MB flash)
- Limited I/O pins for sensors and peripherals
- SD card for external storage (subject to wear and failure)
- Power: Continuous AC power (with brief interruptions)
2.4.2 Software Constraints
- ESP-IDF v5.4 framework
- FreeRTOS for task scheduling
- C/C++ programming languages
- No dynamic memory allocation in critical paths
2.4.3 Regulatory Constraints
- Animal welfare regulations compliance
- Environmental monitoring standards
- Security requirements (encryption, authentication)
2.4.4 Operational Constraints
- Harsh environment (humidity, dust, ammonia)
- Unattended operation (24/7)
- Remote deployment (limited physical access)
2.5 Assumptions and Dependencies
Assumptions:
- Sensors are pre-configured and compatible
- Main Hub provides time synchronization
- Cryptographic keys are securely provisioned
- Power interruptions are brief (< 1 second)
Dependencies:
- ESP-IDF framework availability and stability
- Sensor driver availability
- Main Hub communication protocol compatibility
3. Specific Requirements
3.1 Functional Requirements
3.1.1 System State Management (SWR-SYS-001 through SWR-SYS-015)
SWR-SYS-001: The software SHALL implement a finite state machine (FSM) with the following states: INIT, BOOT_FAILURE, RUNNING, WARNING, FAULT, OTA_PREP, OTA_UPDATE, MC_UPDATE, TEARDOWN, SERVICE, SD_DEGRADED.
Traceability: SR-SYS-001
SWR-SYS-002: The software SHALL enforce valid state transitions as defined in the System State Machine Specification.
Traceability: SR-SYS-001
SWR-SYS-003: The software SHALL restrict feature operations based on the current system state according to per-state execution rules.
Traceability: SR-SYS-002
SWR-SYS-004: The software SHALL notify all registered components when a state transition occurs via the Event System.
Traceability: SR-SYS-003
SWR-SYS-005: The software SHALL execute a controlled teardown sequence before firmware updates, machine constant updates, or system resets.
Traceability: SR-SYS-004
SWR-SYS-006: The software SHALL persist all critical runtime data before completing a teardown sequence.
Traceability: SR-SYS-005
SWR-SYS-007: The software SHALL prevent data corruption during teardown and reset operations.
Traceability: SR-SYS-006
SWR-SYS-008: The software SHALL provide a local OLED display interface using I2C communication protocol.
Traceability: SR-SYS-007
SWR-SYS-009: The software SHALL display connectivity status, system state, connected sensor summary, and time/date on the OLED display.
Traceability: SR-SYS-008
SWR-SYS-010: The software SHALL provide menu navigation using Up, Down, and Select buttons.
Traceability: SR-SYS-009
SWR-SYS-011: The software SHALL provide diagnostic, sensor, and health information through the local OLED menu interface.
Traceability: SR-SYS-010
SWR-SYS-012: The software SHALL support diagnostic sessions for retrieving system status and diagnostic data.
Traceability: SR-SYS-011
SWR-SYS-013: The software SHALL support debug sessions allowing controlled engineering commands.
Traceability: SR-SYS-012
SWR-SYS-014: The software SHALL restrict debug session actions to authorized engineering access only.
Traceability: SR-SYS-013
SWR-SYS-015: The software SHALL ensure debug sessions do not interfere with normal sensor acquisition or communication operations.
Traceability: SR-SYS-013, CFC-DBG-01
3.1.2 Sensor Data Acquisition (SWR-DAQ-001 through SWR-DAQ-015)
SWR-DAQ-001: The software SHALL support simultaneous acquisition of environmental data from multiple sensor types (temperature, humidity, CO2, NH3, VOC, particulate matter, light).
Traceability: SR-DAQ-001
SWR-DAQ-002: The software SHALL assign each supported sensor type to a predefined and unique hardware slot.
Traceability: SR-DAQ-002
SWR-DAQ-003: The software SHALL detect the physical presence of each sensor via a dedicated hardware detection signal prior to sensor initialization.
Traceability: SR-DAQ-003
SWR-DAQ-004: The software SHALL initialize and activate only sensors that are detected as present and enabled.
Traceability: SR-DAQ-004
SWR-DAQ-005: The software SHALL sample each enabled sensor multiple times within a single acquisition cycle (default: 10 samples per sensor per cycle).
Traceability: SR-DAQ-005
SWR-DAQ-006: The software SHALL apply a local filtering mechanism to raw sensor samples to produce a single filtered sensor value per acquisition cycle.
Traceability: SR-DAQ-006
SWR-DAQ-007: The software SHALL complete each sensor's sampling and filtering process within a bounded and deterministic time window (maximum 100ms per sensor).
Traceability: SR-DAQ-007, CFC-TIME-02
SWR-DAQ-008: The software SHALL generate a timestamp for each filtered sensor value upon completion of the acquisition and filtering process.
Traceability: SR-DAQ-008
SWR-DAQ-009: The software SHALL generate a timestamped sensor data record containing at minimum: sensor identifier, sensor type, filtered value, unit of measurement, timestamp, and data validity status.
Traceability: SR-DAQ-009
SWR-DAQ-010: The software SHALL maintain the most recent timestamped sensor data record in memory and make it available for persistence and on-demand communication requests.
Traceability: SR-DAQ-010
SWR-DAQ-011: The software SHALL NOT perform sensor acquisition during OTA_UPDATE, MC_UPDATE, or TEARDOWN states.
Traceability: CFC-ARCH-02
SWR-DAQ-012: The software SHALL perform sensor acquisition in a non-blocking manner.
Traceability: CFC-TIME-01
SWR-DAQ-013: The software SHALL use deterministic memory allocation for sensor acquisition buffers (no dynamic allocation in acquisition path).
Traceability: CFC-TIME-02
SWR-DAQ-014: The software SHALL publish sensor data updates via the Event System upon completion of each acquisition cycle.
Traceability: Architecture requirement
SWR-DAQ-015: The software SHALL exclude failed sensors from acquisition cycles as defined by the failure handling model.
Traceability: SR-DQC-009
3.1.3 Data Quality & Calibration (SWR-DQC-001 through SWR-DQC-018)
SWR-DQC-001: The software SHALL detect the physical presence of each sensor using a dedicated hardware-based detection mechanism.
Traceability: SR-DQC-001
SWR-DQC-002: The software SHALL perform sensor presence detection during system startup and after any reinitialization or reconfiguration event.
Traceability: SR-DQC-002
SWR-DQC-003: The software SHALL initialize and activate only sensors that are detected as present.
Traceability: SR-DQC-003
SWR-DQC-004: The software SHALL assign each physical sensor slot to a predefined sensor type.
Traceability: SR-DQC-004
SWR-DQC-005: The software SHALL verify that a detected sensor matches the expected sensor type for its assigned slot.
Traceability: SR-DQC-005
SWR-DQC-006: The software SHALL reject and report any sensor-slot mismatch as a diagnostic event.
Traceability: SR-DQC-006
SWR-DQC-007: The software SHALL continuously monitor sensor responsiveness and signal validity during normal operation.
Traceability: SR-DQC-007
SWR-DQC-008: The software SHALL detect sensor failures including disconnection, non-responsiveness, and out-of-range measurement values.
Traceability: SR-DQC-008
SWR-DQC-009: The software SHALL mark detected faulty sensors as defective and exclude them from data acquisition and reporting.
Traceability: SR-DQC-009
SWR-DQC-010: The software SHALL report detected sensor failures to the Main Hub with timestamps and failure classification.
Traceability: SR-DQC-010
SWR-DQC-011: The software SHALL maintain a Machine Constants dataset defining sensor configuration, calibration parameters, and communication identifiers.
Traceability: SR-DQC-011
SWR-DQC-012: The software SHALL store the Machine Constants dataset in non-volatile storage.
Traceability: SR-DQC-012
SWR-DQC-013: The software SHALL load and apply the Machine Constants dataset during system initialization.
Traceability: SR-DQC-013
SWR-DQC-014: The software SHALL support remote updates of the Machine Constants dataset initiated by the Main Hub.
Traceability: SR-DQC-014
SWR-DQC-015: The software SHALL apply updated Machine Constants only after executing a controlled teardown and reinitialization procedure.
Traceability: SR-DQC-015
SWR-DQC-016: The software SHALL validate Machine Constants integrity before applying updates.
Traceability: SR-SEC-008
SWR-DQC-017: The software SHALL NOT perform sensor calibration during OTA_UPDATE, MC_UPDATE, or TEARDOWN states.
Traceability: CFC-ARCH-02
SWR-DQC-018: The software SHALL access Machine Constants only through the DP component.
Traceability: CFC-ARCH-01, CFC-DATA-01
3.1.4 Communication (SWR-COM-001 through SWR-COM-015)
SWR-COM-001: The software SHALL support bidirectional communication between the Sensor Hub and the Main Hub.
Traceability: SR-COM-001
SWR-COM-002: The software SHALL transmit sensor data, diagnostics information, and system status to the Main Hub.
Traceability: SR-COM-002
SWR-COM-003: The software SHALL receive commands, configuration updates, and firmware update requests from the Main Hub.
Traceability: SR-COM-003
SWR-COM-004: The software SHALL monitor the status of the communication link with the Main Hub and report link availability and failure conditions.
Traceability: SR-COM-004
SWR-COM-005: The software SHALL support on-demand requests from the Main Hub for sensor data.
Traceability: SR-COM-005
SWR-COM-006: The software SHALL respond to on-demand data requests with the most recent timestamped sensor data.
Traceability: SR-COM-006
SWR-COM-007: The software SHALL include sensor status and data validity information in on-demand data responses.
Traceability: SR-COM-007
SWR-COM-008: The software SHALL support limited peer-to-peer communication between Sensor Hubs for connectivity checks and time synchronization.
Traceability: SR-COM-008, SR-COM-009
SWR-COM-009: The software SHALL ensure that peer Sensor Hub communication does not interfere with Main Hub communication or control operations.
Traceability: SR-COM-010
SWR-COM-010: The software SHALL encrypt all communication with the Main Hub using authenticated encryption.
Traceability: SR-SEC-009, CFC-SEC-02
SWR-COM-011: The software SHALL ensure integrity and authenticity of all transmitted and received messages.
Traceability: SR-SEC-010
SWR-COM-012: The software SHALL limit communication operations during TEARDOWN state to session closure only.
Traceability: CFC-ARCH-02
SWR-COM-013: The software SHALL perform communication operations in a non-blocking manner.
Traceability: CFC-TIME-01
SWR-COM-014: The software SHALL report communication link failures as diagnostic events according to the failure handling model.
Traceability: SR-COM-004, Failure Handling Model
SWR-COM-015: The software SHALL detect and report communication security violations to the Main Hub.
Traceability: SR-SEC-012
3.1.5 Diagnostics & Health Monitoring (SWR-DIAG-001 through SWR-DIAG-018)
SWR-DIAG-001: The software SHALL implement a diagnostic code framework for reporting system health conditions, warnings, errors, and fatal faults.
Traceability: SR-DIAG-001
SWR-DIAG-002: The software SHALL assign a unique diagnostic code to each detected fault or abnormal condition.
Traceability: SR-DIAG-002
SWR-DIAG-003: The software SHALL classify diagnostic codes by severity level (INFO, WARNING, ERROR, FATAL).
Traceability: SR-DIAG-003
SWR-DIAG-004: The software SHALL associate each diagnostic event with a timestamp and the originating system component.
Traceability: SR-DIAG-004
SWR-DIAG-005: The software SHALL persist diagnostic events in non-volatile storage.
Traceability: SR-DIAG-005
SWR-DIAG-006: The software SHALL retain diagnostic data across system resets and power cycles.
Traceability: SR-DIAG-006
SWR-DIAG-007: The software SHALL implement a bounded diagnostic storage mechanism with a defined overwrite or rollover policy.
Traceability: SR-DIAG-007
SWR-DIAG-008: The software SHALL provide a diagnostic session interface for accessing diagnostic and system health data.
Traceability: SR-DIAG-008
SWR-DIAG-009: The software SHALL allow authorized diagnostic sessions to retrieve stored diagnostic events.
Traceability: SR-DIAG-009
SWR-DIAG-010: The software SHALL allow authorized diagnostic sessions to clear stored diagnostic records.
Traceability: SR-DIAG-010
SWR-DIAG-011: The software SHALL ensure that diagnostic sessions do not interfere with normal sensor acquisition or communication operations.
Traceability: SR-DIAG-011, CFC-DBG-01
SWR-DIAG-012: The software SHALL trigger state transitions based on diagnostic severity according to the failure handling model.
Traceability: Failure Handling Model, SR-SYS-002
SWR-DIAG-013: The software SHALL implement fault latching behavior as defined in the failure handling model.
Traceability: Failure Handling Model
SWR-DIAG-014: The software SHALL implement fault escalation rules as defined in the failure handling model.
Traceability: Failure Handling Model
SWR-DIAG-015: The software SHALL report WARNING, ERROR, and FATAL diagnostic events to the Main Hub.
Traceability: SR-COM-002
SWR-DIAG-016: The software SHALL provide diagnostic information through the local OLED menu interface.
Traceability: SR-SYS-010
SWR-DIAG-017: The software SHALL access diagnostic storage only through the DP component.
Traceability: CFC-ARCH-01, CFC-DATA-01
SWR-DIAG-018: The software SHALL NOT generate new diagnostic events during TEARDOWN state (except teardown-specific diagnostics).
Traceability: CFC-ARCH-02
3.1.6 Persistence & Data Management (SWR-DATA-001 through SWR-DATA-015)
SWR-DATA-001: The software SHALL persist timestamped sensor data in non-volatile storage.
Traceability: SR-DATA-001
SWR-DATA-002: The software SHALL store sensor data together with sensor identifiers, timestamps, and validity status.
Traceability: SR-DATA-002
SWR-DATA-003: The software SHALL support configurable data retention and overwrite policies for persisted sensor data.
Traceability: SR-DATA-003
SWR-DATA-004: The software SHALL provide a Data Persistence (DP) component as the sole interface for persistent data access.
Traceability: SR-DATA-004, CFC-ARCH-01
SWR-DATA-005: The software SHALL prevent application and feature modules from directly accessing storage hardware.
Traceability: SR-DATA-005, CFC-ARCH-01
SWR-DATA-006: The DP component SHALL support serialization and deserialization of structured system data.
Traceability: SR-DATA-006
SWR-DATA-007: The software SHALL flush all critical runtime data to non-volatile storage before entering a controlled teardown or reset state.
Traceability: SR-DATA-007, SR-SYS-005
SWR-DATA-008: The software SHALL protect data integrity during firmware updates and machine constant updates.
Traceability: SR-DATA-008
SWR-DATA-009: The software SHALL verify successful data persistence before completing a system state transition.
Traceability: SR-DATA-009, CFC-DATA-02
SWR-DATA-010: The software SHALL NOT perform data write operations during TEARDOWN state unless explicitly authorized by the System Manager.
Traceability: CFC-DATA-02
SWR-DATA-011: The software SHALL ensure persistence completion is confirmed before state transitions.
Traceability: CFC-DATA-02
SWR-DATA-012: The software SHALL handle SD card failures gracefully by entering SD_DEGRADED state and disabling persistence writes.
Traceability: System State Machine Specification
SWR-DATA-013: The software SHALL implement wear-aware storage management to prevent premature SD card failure.
Traceability: Quality requirement
SWR-DATA-014: The software SHALL maintain a single source of truth for runtime and persistent data through the DP component.
Traceability: CFC-DATA-01
SWR-DATA-015: The software SHALL NOT allow features to maintain private persistent copies of shared system data.
Traceability: CFC-DATA-01
3.1.7 Firmware Update (OTA) (SWR-OTA-001 through SWR-OTA-020)
SWR-OTA-001: The software SHALL support OTA update negotiation initiated by the Main Hub.
Traceability: SR-OTA-001
SWR-OTA-002: The software SHALL verify internal readiness conditions before accepting an OTA update request.
Traceability: SR-OTA-002
SWR-OTA-003: The software SHALL explicitly acknowledge or reject OTA update requests.
Traceability: SR-OTA-003
SWR-OTA-004: The software SHALL receive firmware images over the established communication interface.
Traceability: SR-OTA-004
SWR-OTA-005: The software SHALL store received firmware images in non-volatile storage prior to validation.
Traceability: SR-OTA-005
SWR-OTA-006: The software SHALL prevent overwriting the active firmware during firmware reception.
Traceability: SR-OTA-006
SWR-OTA-007: The software SHALL validate the integrity of received firmware images before activation.
Traceability: SR-OTA-007
SWR-OTA-008: The software SHALL reject firmware images that fail integrity validation.
Traceability: SR-OTA-008
SWR-OTA-009: The software SHALL report firmware validation and OTA status to the Main Hub.
Traceability: SR-OTA-009
SWR-OTA-010: The software SHALL execute a controlled teardown procedure prior to firmware activation.
Traceability: SR-OTA-010, SR-SYS-004
SWR-OTA-011: The software SHALL persist critical runtime data and calibration data before flashing new firmware.
Traceability: SR-OTA-011, SR-SYS-005
SWR-OTA-012: The software SHALL activate new firmware only after successful integrity validation.
Traceability: SR-OTA-012
SWR-OTA-013: The software SHALL reboot into the new firmware after successful activation.
Traceability: SR-OTA-013
SWR-OTA-014: The software SHALL use encrypted and authenticated communication channels for OTA firmware updates.
Traceability: SR-SEC-011, CFC-SEC-02
SWR-OTA-015: The software SHALL transition to OTA_PREP state upon accepting an OTA request.
Traceability: System State Machine Specification
SWR-OTA-016: The software SHALL NOT allow OTA operations during WARNING, FAULT, SERVICE, or SD_DEGRADED states.
Traceability: System State Machine Specification, CFC-ARCH-02
SWR-OTA-017: The software SHALL complete OTA operations within a maximum duration of 10 minutes.
Traceability: Quality requirement
SWR-OTA-018: The software SHALL handle OTA failures by transitioning to FAULT state and reporting the failure.
Traceability: System State Machine Specification, Failure Handling Model
SWR-OTA-019: The software SHALL protect active firmware from corruption during OTA operations.
Traceability: SR-OTA-006
SWR-OTA-020: The software SHALL verify firmware authenticity using secure boot mechanisms before execution.
Traceability: SR-SEC-001, SR-SEC-002
3.1.8 Security & Safety (SWR-SEC-001 through SWR-SEC-020)
SWR-SEC-001: The software SHALL verify the authenticity of the firmware image before execution during every boot cycle.
Traceability: SR-SEC-001, CFC-SEC-01
SWR-SEC-002: The software SHALL prevent execution of firmware images that fail cryptographic verification.
Traceability: SR-SEC-002
SWR-SEC-003: The software SHALL enter BOOT_FAILURE state when secure boot verification fails.
Traceability: SR-SEC-003, System State Machine Specification
SWR-SEC-004: The software SHALL protect the root-of-trust against unauthorized modification.
Traceability: SR-SEC-004
SWR-SEC-005: The software SHALL protect sensitive data stored in internal flash memory from unauthorized access.
Traceability: SR-SEC-005
SWR-SEC-006: The software SHALL support encryption of sensitive data stored in external storage devices.
Traceability: SR-SEC-006
SWR-SEC-007: The software SHALL restrict access to cryptographic keys to authorized system components only.
Traceability: SR-SEC-007
SWR-SEC-008: The software SHALL ensure integrity of stored configuration, calibration, and machine constant data.
Traceability: SR-SEC-008
SWR-SEC-009: The software SHALL encrypt all communication with the Main Hub.
Traceability: SR-SEC-009, CFC-SEC-02
SWR-SEC-010: The software SHALL ensure integrity and authenticity of all transmitted and received messages.
Traceability: SR-SEC-010
SWR-SEC-011: The software SHALL use encrypted and authenticated communication channels for OTA firmware updates.
Traceability: SR-SEC-011, CFC-SEC-02
SWR-SEC-012: The software SHALL detect and report communication and security violations to the Main Hub.
Traceability: SR-SEC-012
SWR-SEC-013: The software SHALL enable secure boot and flash protection before any application-level logic executes.
Traceability: CFC-SEC-01
SWR-SEC-014: The software SHALL authenticate debug sessions before allowing debug operations.
Traceability: SR-SYS-013, CFC-DBG-01
SWR-SEC-015: The software SHALL NOT allow debug sessions to bypass security or safety mechanisms.
Traceability: CFC-DBG-01
SWR-SEC-016: The software SHALL report security violations as FATAL diagnostic events.
Traceability: Failure Handling Model
SWR-SEC-017: The software SHALL protect cryptographic keys during power loss and system resets.
Traceability: Quality requirement
SWR-SEC-018: The software SHALL implement secure session establishment for all external communication.
Traceability: SR-SEC-009
SWR-SEC-019: The software SHALL validate message integrity on every received message.
Traceability: SR-SEC-010
SWR-SEC-020: The software SHALL prevent downgrade attacks by verifying firmware version integrity.
Traceability: Quality requirement
3.2 Interface Requirements
3.2.1 External Interfaces
SWR-IF-001: The software SHALL provide a communication interface to the Main Hub supporting bidirectional data exchange.
Traceability: SR-COM-001
SWR-IF-002: The software SHALL provide sensor interfaces supporting I2C, SPI, UART, and analog protocols.
Traceability: Architecture requirement
SWR-IF-003: The software SHALL provide an I2C interface for OLED display communication.
Traceability: SR-SYS-007
SWR-IF-004: The software SHALL provide GPIO interfaces for button inputs (Up, Down, Select).
Traceability: SR-SYS-009
SWR-IF-005: The software SHALL provide storage interfaces for SD card and NVM access.
Traceability: Architecture requirement
SWR-IF-006: The software SHALL provide a debug interface (UART/USB) for diagnostic and debug sessions.
Traceability: SR-SYS-011, SR-SYS-012
3.2.2 Internal Interfaces
SWR-IF-007: The software SHALL provide an Event System interface for cross-component communication.
Traceability: Architecture requirement
SWR-IF-008: The software SHALL provide a Data Pool interface for runtime data access.
Traceability: Architecture requirement
SWR-IF-009: The software SHALL provide a Data Persistence (DP) component interface for persistent storage access.
Traceability: SR-DATA-004, CFC-ARCH-01
SWR-IF-010: The software SHALL provide a System State Manager interface for state queries and transitions.
Traceability: SR-SYS-001
SWR-IF-011: The software SHALL provide a Diagnostics interface for fault reporting and querying.
Traceability: SR-DIAG-001
SWR-IF-012: The software SHALL provide an Error Handler interface for fault classification and escalation.
Traceability: Failure Handling Model
3.3 Performance Requirements
SWR-PERF-001: The software SHALL complete sensor acquisition cycles within 100ms per sensor.
Traceability: SR-DAQ-007, CFC-TIME-02
SWR-PERF-002: The software SHALL complete state transitions within 50ms (except INIT → RUNNING: 5s, TEARDOWN: 500ms).
Traceability: System State Machine Specification
SWR-PERF-003: The software SHALL complete data persistence operations within 200ms.
Traceability: Quality requirement
SWR-PERF-004: The software SHALL complete OTA operations within 10 minutes.
Traceability: SWR-OTA-017
SWR-PERF-005: The software SHALL maintain CPU utilization below 80% during normal operation.
Traceability: Quality requirement
SWR-PERF-006: The software SHALL maintain RAM usage below 60% of available memory.
Traceability: Quality requirement
SWR-PERF-007: The software SHALL respond to Main Hub data requests within 100ms.
Traceability: SR-COM-005, SR-COM-006
SWR-PERF-008: The software SHALL detect communication link failures within 30 seconds.
Traceability: SR-COM-004
3.4 Design Constraints
SWR-DESIGN-001: The software SHALL NOT use dynamic memory allocation in sensor acquisition paths.
Traceability: CFC-TIME-02
SWR-DESIGN-002: The software SHALL implement all features as non-blocking operations.
Traceability: CFC-TIME-01
SWR-DESIGN-003: The software SHALL access hardware only through driver and OSAL layers.
Traceability: CFC-ARCH-01
SWR-DESIGN-004: The software SHALL access persistent storage only through the DP component.
Traceability: CFC-ARCH-01, CFC-DATA-01
SWR-DESIGN-005: The software SHALL respect system state restrictions for all operations.
Traceability: CFC-ARCH-02
SWR-DESIGN-006: The software SHALL use the Event System for all cross-component communication.
Traceability: Architecture requirement
3.5 Quality Attributes
SWR-QUAL-001: The software SHALL recover gracefully from power interruptions (< 1 second).
Traceability: System Assumptions
SWR-QUAL-002: The software SHALL handle SD card failures without system failure.
Traceability: System Limitations
SWR-QUAL-003: The software SHALL maintain data integrity during firmware updates.
Traceability: SR-DATA-008
SWR-QUAL-004: The software SHALL prevent unauthorized firmware execution.
Traceability: SR-SEC-001, SR-SEC-002
SWR-QUAL-005: The software SHALL provide deterministic behavior under all operational conditions.
Traceability: CFC-TIME-02
4. Annexes
See separate annex documents:
- Annex A: Software Requirements Traceability Matrix (
Annex_A_Traceability.md) - Annex B: External Interface Specifications (
Annex_B_Interfaces.md) - Annex C: Timing and Resource Budgets (
Annex_C_Budgets.md)