RadPro-Link

Firmware for Seeed Studio XIAO nRF54L15 that bridges a RadPro device UART link to BLE (Nordic UART Service).

What It Does

• Bridges UART data bidirectionally between RadPro and BLE NUS.
• Uses a pairing window on boot (default 1 minute), then allows only bonded devices.
• Stores up to 4 bonds in NVS and overwrites the oldest when full.
• Enforces encrypted BLE links (BT_SECURITY_L2+) before data forwarding.
• Exposes MCUmgr-over-BLE (SMP) for OTA firmware update flows.

Hardware

• Board: Seeed Studio XIAO nRF54L15
• RadPro device with UART
• UART wiring (from zephyr/boards/xiao_nrf54l15_nrf54l15_cpuapp.overlay):
  • XIAO D6 / P2.8 (TX) -> RadPro RX
  • XIAO D7 / P2.7 (RX) -> RadPro TX
  • GND -> GND
• BLE device name: RadPro-Link

Build and Flash

Prerequisite: PlatformIO CLI installed.

pio run
pio run -t upload

Default PlatformIO environment is seeed-xiao-nrf54l15 (platformio.ini).

Factory Reset

Restore factory settings on XIAO nRF54L15 if the board gets into a bad state (for example, upload failures caused by internal NVM write protection).

The factory reset flow performs a flash mass erase and programs factory firmware.

The platform-seeedboards scripts are not committed in this repository. Clone the upstream repository and use the scripts from there:

git clone https://github.com/Seeed-Studio/platform-seeedboards.git
cd platform-seeedboards/scripts/factory_reset

The scripts automatically create/manage a local Python virtual environment and install required tools.

Windows

cd platform-seeedboards\scripts\factory_reset
.\factory_reset.bat

Linux and macOS

bash factory_reset.sh

Reference: https://github.com/Seeed-Studio/platform-seeedboards/tree/main/scripts/factory_reset

Runtime Behavior

Pairing and Security

• Pairing is accepted only during the startup window (PAIRING_WINDOW_MS in src/main.c).
• After the window closes, new pairing is rejected and only existing bonds can reconnect.
• Data path checks:
  • UART -> BLE sends only when BLE link is authenticated/encrypted.
  • BLE -> UART input is dropped when connection security is below L2.

LED Status

Single onboard LED (led0) patterns:

• 100 ms blink: error
• 250 ms blink: pairing window open, not connected
• 500 ms blink: pairing window open, connected
• off: pairing window closed

OTA / DFU

DFU module initializes MCUmgr SMP over BLE (src/dfu/dfu_service.c).

Relevant config in zephyr/prj.conf:

• CONFIG_BOOTLOADER_MCUBOOT=y
• CONFIG_MCUMGR=y
• CONFIG_MCUMGR_TRANSPORT_BT=y
• CONFIG_MCUMGR_TRANSPORT_BT_PERM_RW_AUTHEN=y

Use an MCUmgr-compatible client (for example nRF Connect Device Manager) for OTA operations.

Logs and Monitoring

This repo currently has mixed console/log settings:

• zephyr/prj.conf enables CONFIG_UART_CONSOLE and CONFIG_LOG_BACKEND_UART
• zephyr/boards/xiao_nrf54l15_nrf54l15_cpuapp.conf enables CONFIG_RTT_CONSOLE

If pio device monitor does not show logs in your setup, use RTT tools (for example Segger RTT client) via SWD.

Configuration Knobs

• Pairing window: src/main.c (PAIRING_WINDOW_MS)
• BLE name / bond limit / MCUmgr: zephyr/prj.conf
• Bridge UART selection/pins: zephyr/boards/xiao_nrf54l15_nrf54l15_cpuapp.overlay

Repo Layout

src/
  main.c                  app init and data flow wiring
  ble/                    BLE advertising, NUS, connection/security callbacks
  uart/                   async UART bridge and buffering
  security/               pairing-window policy and auth callbacks
  led/                    status LED thread/patterns
  board/                  board abstraction/init
  dfu/                    MCUmgr/OTA init hook
zephyr/
  prj.conf                Zephyr/Kconfig settings
  CMakeLists.txt          app sources/includes
  boards/                 board overlay/conf

License

MIT