Nrf5340 Device Interaction

Interact with nRF5340 devices over BLE, USB serial, and J-Link. Covers DFU firmware updates via mcumgr, BLE GATT service exploration, nRF Connect SDK CLI tools, RTT logging, and Zephyr shell commands. Use when flashing firmware, debugging BLE connections, reading sensor data, or managing nRF5340-based BCI receivers.

plurigrid 33ef6fb 9 files · 143.0 KB Updated Sep 17, 2026

Coding & Dev Tools

Install

Press C to copy

$ npx skillmds@latest add plurigrid/nrf5340-device-interaction

Installs into ~/.claude/skills (or .claude/skills inside a project). Restart Claude Code to pick it up.

＋ Add to collection

README badge

[![SkillMD](https://skillmd.com/badge/plurigrid/nrf5340-device-interaction.svg)](https://skillmd.com/skills/plurigrid/nrf5340-device-interaction)

Trust & safety

Audits pending

Not yet audited · commit 33ef6fb

Works with: Claude Code Claude.ai OpenAI Codex +

File contents

nRF5340 Device Interaction

Talk to nRF5340 devices. Flash, debug, stream, monitor.

Connection Methods

Method	Tool	Speed	Use Case
J-Link SWD	nrfjprog / west flash	Fast	Development, full flash
USB Serial	screen / minicom	115200	Zephyr shell, logs
BLE	nRF Connect app / bluetoothctl	Wireless	Production DFU, GATT
RTT	J-Link RTT Viewer	Real-time	Debug logging (no UART needed)

Flash Firmware

# Via west (preferred)
west flash --erase

# Via nrfjprog (J-Link)
nrfjprog --program app.hex --chiperase --verify
nrfjprog --reset

# Flash network core separately
nrfjprog --program net_core.hex --coprocessor CP_NETWORK --chiperase
nrfjprog --reset

# Recover bricked device
nrfjprog --recover
nrfjprog --recover --coprocessor CP_NETWORK

DFU Over BLE (mcumgr)

# List images on device
mcumgr --conntype ble --connstring peer_name=BCI_RX image list

# Upload new firmware
mcumgr --conntype ble --connstring peer_name=BCI_RX image upload app_update.bin

# Confirm and reset
mcumgr --conntype ble --connstring peer_name=BCI_RX image confirm
mcumgr --conntype ble --connstring peer_name=BCI_RX reset

DFU Over USB

# Create DFU package
nrfutil pkg generate --hw-version 52 --sd-req 0x00 \
  --application app.hex --application-version 1 dfu_pkg.zip

# Flash via USB serial
nrfutil dfu serial -pkg dfu_pkg.zip -p /dev/cu.usbmodem* -b 115200

BLE GATT Exploration

# Scan for nRF5340 devices
bluetoothctl
> scan on
# Look for "BCI_RX" or "nRF5340"
> scan off
> connect AA:BB:CC:DD:EE:FF

# List services
gatttool -b AA:BB:CC:DD:EE:FF --primary

# Nordic UART Service (NUS) — common for BCI data streaming
# Service UUID: 6e400001-b5a3-f393-e0a9-e50e24dcca9e
# TX Char:      6e400003-b5a3-f393-e0a9-e50e24dcca9e (notify)
# RX Char:      6e400002-b5a3-f393-e0a9-e50e24dcca9e (write)

# Subscribe to notifications (BCI data stream)
gatttool -b AA:BB:CC:DD:EE:FF --char-write-req -a 0x0012 -n 0100 --listen

Zephyr Shell (USB Serial)

# Connect to Zephyr shell
screen /dev/cu.usbmodem* 115200

# Useful shell commands
> kernel version
> kernel threads
> kernel stacks
> device list
> sensor get bme280
> flash read 0 0x0 32
> bt scan on
> bt connect AA:BB:CC:DD:EE:FF public
> log enable dbg app

RTT Logging (No UART Pins Needed)

# Start J-Link RTT server
JLinkRTTViewerExe

# Or via command line
JLinkExe -device nRF5340_xxAA_APP -if SWD -speed 4000
> connect
> r
# RTT output appears automatically

# In Zephyr, enable RTT backend:
# CONFIG_USE_SEGGER_RTT=y
# CONFIG_LOG_BACKEND_RTT=y
# CONFIG_SHELL_BACKEND_RTT=y

BCI Data Streaming Protocol

The zig-syrup-bci receiver uses NUS (Nordic UART Service) to stream:

Packet: [0xBC] [modality] [channel_count] [sample_count] [data...] [crc8]

Modality bytes:
  0x01 = EEG (from Cyton dongle relay)
  0x02 = fNIRS (from OpenNIRScap ADC)
  0x03 = Eye tracking (from Tobii/Pupil)
  0x04 = IMU (from onboard LSM6DSO)
  0x05 = Pose (from MediaPipe relay)

GF(3) trit per packet:
  EEG=0, fNIRS=+1, Eye=-1, IMU=0, Pose=0

Power Profiling

# nRF Power Profiler Kit II
nrfutil toolchain-manager launch --ncs-version v2.6.0 -- \
  nrfutil ppk2 measure --period 10 --average

# Expected current draw:
# BLE advertising: ~1.5 mA
# BLE connected, streaming NUS: ~3.5 mA
# BLE + SPI ADC polling: ~5 mA
# System OFF: ~0.4 µA

Troubleshooting

Symptom	Cause	Fix
nrfjprog: no debugger	J-Link not connected	Check USB, install J-Link drivers
BLE not advertising	Network core not flashed	Flash net core: `west flash --domain cpunet`
GATT empty	Services not registered	Check `bt_gatt_service_register()` in firmware
DFU fails "no slot"	MCUboot not configured	Build with `-DCONFIG_BOOTLOADER_MCUBOOT=y`
RTT no output	Wrong device selected	Use `nRF5340_xxAA_APP` not `nRF5340_xxAA_NET`
NUS no data	Notifications not enabled	Write `0100` to CCCD handle
High current in sleep	UART/SPI left active	Disable peripherals before sleep

Related Skills

Skill	Connection
nrf5340-hardware	Pin assignments, power domains, peripherals
cyton-dongle	2.4GHz EEG data source relayed through nRF5340
zig-syrup-bci	Firmware consuming this device's BLE stream
opennirscap-build	fNIRS sensor board connected via SPI to nRF5340

---name: nrf5340-device-interactiondescription: Interact with nRF5340 devices over BLE, USB serial, and J-Link. Covers DFU firmware updates via mcumgr, BLE GATT service exploration, nRF Connect SDK CLI tools, RTT logging, and Zephyr shell commands. Use when flashing firmware, debugging BLE connections, reading sensor data, or managing nRF5340-based BCI receivers.---# nRF5340 Device InteractionTalk to nRF5340 devices. Flash, debug, stream, monitor.## Connection Methods| Method | Tool | Speed | Use Case ||--------|------|-------|----------|| J-Link SWD | nrfjprog / west flash | Fast | Development, full flash || USB Serial | screen / minicom | 115200 | Zephyr shell, logs || BLE | nRF Connect app / bluetoothctl | Wireless | Production DFU, GATT || RTT | J-Link RTT Viewer | Real-time | Debug logging (no UART needed) |## Flash Firmware```bash# Via west (preferred)west flash --erase# Via nrfjprog (J-Link)nrfjprog --program app.hex --chiperase --verifynrfjprog --reset# Flash network core separatelynrfjprog --program net_core.hex --coprocessor CP_NETWORK --chiperasenrfjprog --reset# Recover bricked devicenrfjprog --recovernrfjprog --recover --coprocessor CP_NETWORK```## DFU Over BLE (mcumgr)```bash# List images on devicemcumgr --conntype ble --connstring peer_name=BCI_RX image list# Upload new firmwaremcumgr --conntype ble --connstring peer_name=BCI_RX image upload app_update.bin# Confirm and resetmcumgr --conntype ble --connstring peer_name=BCI_RX image confirmmcumgr --conntype ble --connstring peer_name=BCI_RX reset```## DFU Over USB```bash# Create DFU packagenrfutil pkg generate --hw-version 52 --sd-req 0x00 \ --application app.hex --application-version 1 dfu_pkg.zip# Flash via USB serialnrfutil dfu serial -pkg dfu_pkg.zip -p /dev/cu.usbmodem* -b 115200```## BLE GATT Exploration```bash# Scan for nRF5340 devicesbluetoothctl> scan on# Look for "BCI_RX" or "nRF5340"> scan off> connect AA:BB:CC:DD:EE:FF# List servicesgatttool -b AA:BB:CC:DD:EE:FF --primary# Nordic UART Service (NUS) — common for BCI data streaming# Service UUID: 6e400001-b5a3-f393-e0a9-e50e24dcca9e# TX Char: 6e400003-b5a3-f393-e0a9-e50e24dcca9e (notify)# RX Char: 6e400002-b5a3-f393-e0a9-e50e24dcca9e (write)# Subscribe to notifications (BCI data stream)gatttool -b AA:BB:CC:DD:EE:FF --char-write-req -a 0x0012 -n 0100 --listen```## Zephyr Shell (USB Serial)```bash# Connect to Zephyr shellscreen /dev/cu.usbmodem* 115200# Useful shell commands> kernel version> kernel threads> kernel stacks> device list> sensor get bme280> flash read 0 0x0 32> bt scan on> bt connect AA:BB:CC:DD:EE:FF public> log enable dbg app```## RTT Logging (No UART Pins Needed)```bash# Start J-Link RTT serverJLinkRTTViewerExe# Or via command lineJLinkExe -device nRF5340_xxAA_APP -if SWD -speed 4000> connect> r# RTT output appears automatically# In Zephyr, enable RTT backend:# CONFIG_USE_SEGGER_RTT=y# CONFIG_LOG_BACKEND_RTT=y# CONFIG_SHELL_BACKEND_RTT=y```## BCI Data Streaming ProtocolThe zig-syrup-bci receiver uses NUS (Nordic UART Service) to stream:```Packet: [0xBC] [modality] [channel_count] [sample_count] [data...] [crc8]Modality bytes: 0x01 = EEG (from Cyton dongle relay) 0x02 = fNIRS (from OpenNIRScap ADC) 0x03 = Eye tracking (from Tobii/Pupil) 0x04 = IMU (from onboard LSM6DSO) 0x05 = Pose (from MediaPipe relay)GF(3) trit per packet: EEG=0, fNIRS=+1, Eye=-1, IMU=0, Pose=0```## Power Profiling```bash# nRF Power Profiler Kit IInrfutil toolchain-manager launch --ncs-version v2.6.0 -- \ nrfutil ppk2 measure --period 10 --average# Expected current draw:# BLE advertising: ~1.5 mA# BLE connected, streaming NUS: ~3.5 mA# BLE + SPI ADC polling: ~5 mA# System OFF: ~0.4 µA```## Troubleshooting| Symptom | Cause | Fix ||---------|-------|-----|| nrfjprog: no debugger | J-Link not connected | Check USB, install J-Link drivers || BLE not advertising | Network core not flashed | Flash net core: `west flash --domain cpunet` || GATT empty | Services not registered | Check `bt_gatt_service_register()` in firmware || DFU fails "no slot" | MCUboot not configured | Build with `-DCONFIG_BOOTLOADER_MCUBOOT=y` || RTT no output | Wrong device selected | Use `nRF5340_xxAA_APP` not `nRF5340_xxAA_NET` || NUS no data | Notifications not enabled | Write `0100` to CCCD handle || High current in sleep | UART/SPI left active | Disable peripherals before sleep |## Related Skills| Skill | Connection ||-------|-----------|| nrf5340-hardware | Pin assignments, power domains, peripherals || cyton-dongle | 2.4GHz EEG data source relayed through nRF5340 || zig-syrup-bci | Firmware consuming this device's BLE stream || opennirscap-build | fNIRS sensor board connected via SPI to nRF5340 |

plurigrid/asi/tree/main/skills/nrf5340-device-interaction commit 33ef6fbcc6

Frequently asked questions

npx skillmds@latest add plurigrid/nrf5340-device-interaction