TestBLE

Embedded BLE file transfer, fNIRS acquisition, OTA, and a Flutter monitor for the Ingenic X2600 platform.

TestBLE combines an embedded BlueZ GATT server with the my-fnirs board service. The board discovers CAN-FD sensor nodes, drives dual-wavelength LEDs, records timestamped samples, streams live data, transfers finalized recordings, and updates node firmware. A Flutter client provides scan, control, waveform, and file-transfer workflows.

This is hardware-specific engineering and research software. It is not a medical device and must not be used for diagnosis or treatment.

Highlights

• BLE GATT upload, download, and live-tail synchronization
• CRC-protected packets, cumulative ACK flow control, and retry handling
• CAN-FD fNIRS node discovery and 10 Hz sample/upload state machine
• Per-frame millisecond timestamps in recorded data
• Node OTA file validation, transfer, completion bitmap, and result reporting
• One process for fNIRS business logic and embedded GATT
• Production libevent backend plus an opt-in libuv comparison build
• Flutter monitor with node scan, LED sequence control, waveforms, and file sync

Repository layout

Path	Purpose
sdk-overlay/packages/example/x2600-fNIRS/	Board service, CAN-FD, UART, recording, OTA, event/UV backends
sdk-overlay/packages/example/ble_hci_test/	Embedded GATT server, protocol notes, and PC utilities
sdk-overlay/packages/example/ble_hci_test/mobile_app/	Flutter application
sdk-overlay/device/x2600halley7/	Build integration, init configuration, deployment, and validation scripts
docs/	Architecture and refactor notes

The repository is a source overlay, not a copy of the full Ingenic SDK. This keeps generated output, vendor firmware, release keys, and board-test binaries out of the public history.

Architecture

Flutter / PC tools
        │ BLE GATT
        ▼
my-fnirs
├── embedded BlueZ GATT server
├── libevent main loop (default)
│   ├── CAN-FD node scan / sample / OTA
│   ├── UART host protocol
│   ├── recording and live-file synchronization
│   └── timers and signal handling
└── libuv compatibility backend (optional comparison build)
        │
        ▼
X2600 hub ── CAN-FD ── fNIRS sensor nodes

The two backends compile the same business sources. my-fnirs uses libevent and remains the default. my-fnirs-uv is an explicitly selected comparison binary; both processes must never own the hardware at the same time.

Build

Requirements:

• Ingenic Linux SDK v4.1 for x2600halley7
• the matching Buildroot/BlueZ source tree
• Flutter 3.16 or newer for the mobile app
• ADB for deployment

Copy the overlay into an existing SDK:

export SDK_ROOT=/path/to/ingenic-linux-kernel5.10-x2600-v4.1-20250625
rsync -a sdk-overlay/ "$SDK_ROOT"/
cd "$SDK_ROOT"
source build/envsetup.sh
lunch x2600halley7.v10_msc_5.10-eng
make my-fnirs my-fnirs-uv

The production event backend can then be deployed from PowerShell:

cd device\x2600halley7
.\deploy-my-fnirs-ev.ps1 -Build

The UV comparison build is deployed separately:

.\deploy-my-fnirs-uv.ps1 -Build

Runtime selection is stored in /etc/default/fnirs. The checked-in safe default is:

FNIRS_BACKEND=event
FNIRS_UV_AUTOBOOT=0

Mobile app

cd sdk-overlay/packages/example/ble_hci_test/mobile_app
flutter create . --project-name testble_send
flutter pub get
flutter run

The checked-in Dart sources contain the application-specific BLE protocol and UI. flutter create . supplies platform scaffolding when it is not already present.

Validation helpers

After starting and stopping one recording, validate embedded timestamps from PowerShell:

.\check-fnirs-timestamp.ps1

A passing file reports two timestamps and their millisecond delta. Runtime diagnostics are written under /app_data/golgi/ on the board.

Protocol documentation

• BLE framing and tuning
• GATT and mobile workflow
• event-loop refactor report (libevent and libuv)
• libuv comparison backend

Security and licensing

Release signing keys, device logs, generated binaries, vendor firmware, and the full proprietary SDK are intentionally excluded. Use your own credentials and obtain the Ingenic SDK through an authorized channel.

Licensing is file-specific. The BlueZ-derived GATT server is GPL-2.0-or-later; Linux UAPI headers retain their SPDX terms. No project-wide license is granted for files without an explicit license. See THIRD_PARTY_NOTICES.md.