Bluetooth: Peripheral LBS
The peripheral LBS sample demonstrates how to use the LED Button Service (LBS).
Requirements
The sample supports the following development kits:
Hardware platforms |
PCA |
Board name |
Build target |
|---|---|---|---|
PCA20053 |
|
||
PCA10095 |
|
||
PCA10040 |
|
||
PCA10040 |
|
||
PCA10056 |
|
||
PCA10056 |
|
||
PCA10100 |
|
When built for an _ns build target, the sample is configured to compile and run as a non-secure application with Cortex-M Security Extensions enabled.
Therefore, it automatically includes Trusted Firmware-M that prepares the required peripherals and secure services to be available for the application.
The sample also requires a smartphone or tablet running a compatible application. The Testing instructions refer to nRF Connect for Mobile, but you can also use other similar applications (for example, nRF Blinky or nRF Toolbox).
Note
If you build this application for Thingy:53, it enables additional features. See Thingy:53 application guide for details.
Overview
When connected, the sample sends the state of Button 1 on the development kit 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 LED 3 on the development kit.
You can also use this sample to control the color of the RGB LED on the nRF52840 Dongle or Thingy:53.
User interface
The user interface of the sample depends on the hardware platform you are using.
nRF52840 Dongle
- Green LED:
When the main loop is running (that is, the device is advertising), the LED blinks with a period of 2 seconds, duty cycle 50%.
- RGB LED:
The RGB LED channels are used independently to display the following information:
Red - If Dongle is connected.
Green - If user set the LED using Nordic LED Button Service.
- Button 1:
Send a notification with the button state: “pressed” or “released”.
Thingy:53
- RGB LED:
The RGB LED channels are used independently to display the following information:
Red - If the main loop is running (that is, the device is advertising). The LED blinks with a period of 2 seconds, duty cycle 50%.
Green - If the device is connected.
Blue - If user set the LED using Nordic LED Button Service.
For example, if Thingy:53 is connected over Bluetooth, the LED color toggles between green and yellow. The green LED channel is kept on and the red LED channel is blinking.
- Button 1:
Send a notification with the button state: “pressed” or “released”.
Development kits
- LED 1:
Blinks when the main loop is running (that is, the device is advertising) with a period of 2 seconds, duty cycle 50%.
- LED 2:
On when the development kit is connected.
- LED 3:
On when the development kit is controlled remotely from the connected device.
- Button 1:
Send a notification with the button state: “pressed” or “released”.
Building and running
This sample can be found under samples/bluetooth/peripheral_lbs in the nRF Connect SDK folder structure.
When built as firmware image for the _ns build target, the sample has Cortex-M Security Extensions (CMSE) enabled and separates the firmware between Non-Secure Processing Environment (NSPE) and Secure Processing Environment (SPE).
Because of this, it automatically includes the Trusted Firmware-M (TF-M).
To read more about CMSE, see Processing environments.
To build the sample with Visual Studio Code, follow the steps listed on the How to build an application page in the nRF Connect for VS Code extension documentation. See Building and programming an application for other building and programming scenarios and Testing and debugging an application for general information about testing and debugging in the nRF Connect SDK.
Minimal build
You can build the sample with a minimum configuration as a demonstration of how to reduce code size and RAM usage, using the -DCONF_FILE='prj_minimal.conf' flag in your build.
See Providing CMake options for instructions on how to add this option to your build. For example, when building on the command line, you can do so as follows:
west build samples/bluetooth/peripheral_lbs -- -DCONF_FILE='prj_minimal.conf'
Testing
After programming the sample to your dongle or development kit, test it by performing the following steps:
Start the nRF Connect for Mobile application on your smartphone or tablet.
Power on the development kit or insert your dongle into the USB port.
Connect to the device from the application. The device is advertising as
Nordic_LBS. The services of the connected device are shown.In Nordic LED Button Service, enable notifications for the Button characteristic.
Press Button 1 on the device.
Observe that notifications with the following values are displayed:
Button releasedwhen Button 1 is released.Button pressedwhen Button 1 is pressed.
Write the following values to the LED characteristic in the Nordic LED Button Service. Depending on the hardware platform, this produces results described in the table.
Hardware platform |
Value |
Effect |
|---|---|---|
Development kit |
|
Switch the LED3 off. |
|
Switch the LED3 on. |
|
nRF52840 Dongle |
|
Switch the green channel of the RGB LED off. |
|
Switch the green channel of the RGB LED on. |
|
Thingy:53 |
|
Switch the blue channel of the RGB LED off. |
|
Switch the blue channel of the RGB LED on. |
Dependencies
This sample uses the following nRF Connect SDK libraries:
In addition, it uses the following Zephyr libraries:
include/zephyr/types.hlib/libc/minimal/include/errno.hinclude/sys/printk.hinclude/sys/byteorder.h-
include/bluetooth/bluetooth.hinclude/bluetooth/hci.hinclude/bluetooth/conn.hinclude/bluetooth/uuid.hinclude/bluetooth/gatt.h
The sample also uses the following secure firmware component: