Bluetooth: Central Heart Rate Monitor with Coded PHY

The Central Heart Rate Monitor with Coded PHY offers similar functionality to the Heart-rate Monitor (Central) sample from Zephyr. However, this sample specifically looks for heart rate monitors using LE Coded PHY.

Requirements

The sample supports the following development kits:

Hardware platforms

PCA

Board name

Board target

nRF54L15 DK

PCA10156

nrf54l15dk

nrf54l15dk/nrf54l15/cpuapp

nRF54H20 DK

PCA10175

nrf54h20dk

nrf54h20dk/nrf54h20/cpuapp

nRF5340 DK

PCA10095

nrf5340dk

nrf5340dk/nrf5340/cpuapp

nRF52840 DK

PCA10056

nrf52840dk

nrf52840dk/nrf52840

Note

If you use nRF5340 DK, the additional configuration of the network core will be taken from the child_image directory. For more details, see Image-specific variables.

The sample also requires a device running a Heart Rate Server with LE Coded PHY support to connect to. For example, another development kit running the Bluetooth: Peripheral Heart Rate Monitor with Coded PHY sample.

Overview

The sample demonstrates a Bluetooth® LE Central role functionality by scanning for other Bluetooth LE devices that run a Heart Rate Server with LE Coded PHY support, which is not available in Zephyr Bluetooth LE Controller. See Controller for more information. It then establishes a connection to the first Peripheral device in range. You can use it together with the Bluetooth: Peripheral Heart Rate Monitor with Coded PHY sample.

Building and running

This sample can be found under samples/bluetooth/central_hr_coded in the nRF Connect SDK folder structure.

To build the sample, follow the instructions in Building an application for your preferred building environment. See also Programming an application for programming steps and Testing and optimization for general information about testing and debugging in the nRF Connect SDK.

Note

When building repository applications in the SDK repositories, building with sysbuild is enabled by default. If you work with out-of-tree freestanding applications, you need to manually pass the --sysbuild parameter to every build command or configure west to always use it.

Testing

After programming the sample to your development kit, you can test it by connecting to another development kit that runs the Bluetooth: Peripheral Heart Rate Monitor with Coded PHY.

  1. Connect to the kit that runs this sample with a terminal emulator (for example, nRF Connect Serial Terminal). See Testing and optimization for the required settings and steps.

  2. Reset the kit.

  3. Program the other kit with the Bluetooth: Peripheral Heart Rate Monitor with Coded PHY sample.

  4. Wait until the Coded advertiser is detected by the Central. In the terminal window, check for information similar to the following:

    Filters matched. Address: xx.xx.xx.xx.xx.xx (random) connectable: yes
Connection pending
Connected: xx.xx.xx.xx.xx.xx (random), tx_phy 4, rx_phy 4
The discovery procedure succeeded

  5. Observe that the received notifications are output in the terminal window:

    [SUBSCRIBED]
Heart Rate Measurement notification received:

  Heart Rate Measurement Value Format: 8 - bit
  Sensor Contact detected: 1
  Sensor Contact supported: 1
  Energy Expended present: 0
  RR-Intervals present: 0

  Heart Rate Measurement Value: 113 bpm

Dependencies

This sample uses the following nRF Connect SDK libraries:

In addition, it uses the following Zephyr libraries:

  • include/zephyr/types.h

  • include/errno.h

  • include/zephyr.h

  • include/sys/printk.h

  • include/sys/byteorder.h

  • Kernel Services:

    • include/kernel.h

  • API:

  • include/bluetooth/bluetooth.h

  • include/bluetooth/conn.h

  • include/bluetooth/gatt.h

  • include/bluetooth/uuid.h