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Bluetooth Low Energy: Peripheral LBS

Overview

The Peripheral LBS sample demonstrates how to use the LED Button Service (LBS).

When connected, the sample sends the state of USR button on the board to the connected device, such as a phone or tablet. The mobile application on the device can display the received button state and control the state of Green LED on the board.

Requirements

Before you start, check that you have the required hardware and software:

  • 1x nRF54L15 Connect Kit
  • 1x U.FL cabled 2.4 GHz Antenna (included in the box)
  • 1x USB-C Cable
  • A smartphone or a tablet with nRF Blinky installed
  • A computer running macOS, Ubuntu, or Windows 10 or newer

Attaching the 2.4 GHz antenna

Before applying power to the board, ensure the U.FL cabled 2.4 GHz antenna is properly installed.

Building the sample

To build the sample, follow the instructions in Getting Started Guide to set up your preferred building environment.

Use the following steps to build the Peripheral LBS sample on the command line.

  1. Open a terminal window.

  2. Go to NCS-Project/nrf54l15-connectkit repository cloned in the Getting Started Guide.

  3. Build the sample using the west build command, specifying the board (following the -b option) as nrf54l15_connectkit/nrf54l15/cpuapp.

    west build -p always -b nrf54l15_connectkit/nrf54l15/cpuapp samples/bluetooth/peripheral_lbs

    Tip

    The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

  4. After building the sample successfully, the firmware with the name merged.hex can be found in the build directory.

Flashing the firmware

Connect the nRF54L15 Connect Kit to the computer with a USB-C cable:

Then flash the sample using west flash:

west flash

Tip

In case you wonder, the west flash will execute the following command:

pyocd load --target nrf54l --frequency 4000000 build/merged.hex

Testing

After programming the sample, test it by performing the following steps:

  1. Open up a serial terminal, specifying the primary COM port that your computer uses to communicate with the nRF54L15:

    1. Start PuTTY.

    2. Configure the correct serial port and click Open:

    Open up a terminal and run:

    screen <serial-port-name> 115200

    Open up a terminal and run:

    screen <serial-port-name> 115200

  2. Press the DFU/RST button to reset the nRF54L15.

  3. Observe the output of the terminal. You should see the output, similar to what is shown in the following:

    Terminal
    1
2
3
4
5
6
    *** Booting My Application v3.1.0-5da6f6aae060 ***
*** Using nRF Connect SDK v3.1.0-6c6e5b32496e ***
*** Using Zephyr OS v4.1.99-1612683d4010 ***
Starting Bluetooth Peripheral LBS sample
Bluetooth initialized
Advertising successfully started

  4. Open the nRF Blinky app, observe that the board is advertising with the Device Name Nordic_LBS.

  5. Tap Nordic_LBS to establish a connection with the board, then:

    • Toggle the LED switch in the app to turn the Green LED ON/OFF
    • Press the USR button on the board, and the app will show its state (Pressed/Released)