Phase 4 — Wireless Protocol Integration

Configure Bluetooth Low Energy

Set up BLE with Zephyr's Bluetooth stack for advertising, connections, and GATT services.

# prj.conf
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="MyDevice"
CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=2

Initialization flow:

1. bt_enable(NULL) to initialize the stack
2. Define advertising data with BT_DATA macros
3. Register connection callbacks with BT_CONN_CB_DEFINE
4. Start advertising with bt_le_adv_start()

• Use BT_CONN_CB_DEFINE for static callback registration
• Configure connection parameters for your power/latency needs
• Enable CONFIG_BT_SETTINGS to persist bonding information
• Use the nRF Connect mobile app for testing and debugging

See the Zephyr Bluetooth Guide.

Implement GATT services

Create custom BLE services and characteristics for your application.

GATT service pattern:
1. Define custom 128-bit UUIDs with BT_UUID_DECLARE_128
2. Create read/write handlers for characteristics
3. Use BT_GATT_SERVICE_DEFINE to declare the service
4. Include BT_GATT_CCC for notification support
5. Use bt_gatt_notify() to send notifications

• Use 128-bit UUIDs for custom services
• Include CCC (Client Characteristic Configuration) for notifications
• Test with the nRF Connect mobile app's GATT viewer
• Consider using Nordic's GATT Service samples as templates

Add Thread / Zigbee support

Enable mesh networking protocols for smart home and industrial IoT applications.

# prj.conf — Thread
CONFIG_NETWORKING=y
CONFIG_NET_L2_OPENTHREAD=y
CONFIG_OPENTHREAD_NORDIC_LIBRARY_MTD=y
CONFIG_OPENTHREAD_CHANNEL=11
CONFIG_OPENTHREAD_PANID=4660

Use the OpenThread API via openthread_get_default_context().

• Thread requires an IEEE 802.15.4 radio (nRF52840, nRF5340)
• Use the OpenThread CLI sample for initial testing
• Configure network credentials via CLI or programmatically
• Consider Matter for cross-ecosystem compatibility

See the Thread Development Guide.

Configure WiFi for nRF7002

Set up WiFi connectivity using the nRF7002 companion IC.

# prj.conf — WiFi
CONFIG_WIFI=y
CONFIG_WIFI_NRF700X=y
CONFIG_WPA_SUPP=y
CONFIG_NET_L2_WIFI_MGMT=y
CONFIG_NET_DHCPV4=y

Use net_mgmt(NET_REQUEST_WIFI_CONNECT, ...) to connect.

• nRF7002 requires nRF5340 or nRF52840 as host
• Enable WPA3 for enhanced security
• Use low-power modes (TWT) for battery-powered devices
• Test with different access points for compatibility

See the nRF7002 Documentation.

Implement LTE-M / NB-IoT for nRF9160

Set up cellular connectivity for wide-area IoT applications.

# prj.conf — LTE
CONFIG_LTE_LINK_CONTROL=y
CONFIG_NRF_MODEM_LIB=y
CONFIG_MODEM_INFO=y

Initialization:

1. nrf_modem_lib_init() to start the modem
2. lte_lc_register_handler() for events
3. lte_lc_connect_async() to connect to the network

• Use LTE-M for mobility, NB-IoT for stationary sensors
• Configure PSM (Power Saving Mode) and eDRX for power optimization
• Test with nRF Cloud for easy connectivity verification
• Handle network registration and connection loss gracefully

See the nRF9160 Guide.

Develop application state machines

Implement application logic using state machines for reliable operation.

State machine pattern:
1. Define states as enum (INIT, IDLE, ADVERTISING, CONNECTED, ...)
2. Create state handler functions for each state
3. Use a function pointer array for state dispatch
4. Implement transition_to() for state changes
5. Consider Zephyr's SMF for complex state machines

• Use state machines for complex control flow
• Document state transitions with diagrams
• Handle all edge cases and error states
• Use Zephyr's SMF (State Machine Framework) for complex state machines