BLE Examples

This repo contains a collection of BLE example applications based on mbed OS and built with mbed-cli. Each example subdirectory contains a separate mbed-cli module meant for building an executable.

Please browse to subdirectories for specific documentation.

Getting Started

Pre-Requisites

To build these examples, you need to have a computer with software installed as described here.

In order to use BLE in mbed OS you need one of the following hardware combinations:

• A Nordic nRF51-based board such as nrf51dk or mkit.
• A Nordic nRF52-based board such as nrf52DK
• A supported target, such as the NUCLEO-F401RE, with a BLE shield or an external BLE peripheral, such as an ST shield.
• A DISCO_L475VG_IOT01A (ref B-L475E-IOT01A) board.

The BLE documentation describes the BLE APIs on mbed OS.

Targets for BLE

The following targets have been tested and work with these examples:

• Nordic:

  • NRF51_DK
  • NRF52_DK

• Boards with an ST shield plugged in:

  • K64F
  • NUCLEO_F401RE

• STMicroelectronics:

  • DISCO_L475VG_IOT01A (ref B-L475E-IOT01A)

  Important: if an ST shield is used with the K64F board, an hardware is patch required. Check out https://developer.mbed.org/teams/ST/code/X_NUCLEO_IDB0XA1/ for more information.

Using ST Nucleo shield on other targets

It is possible to use the ST Nucleo shield on boards not directly supported by these examples as long as the board has an Arduino UNO R3 connector.

To makes the board compatible with the ST shield three things are required:

• Add the BLE feature to your target.
• Add the BLE implementation for the ST shield to the list of modules which have to be compiled.
• Indicate to the BLE implementation that your board use an Arduino connector.

All these operations can be done in the file mbed_app.json present in every example.

In the section target_overrides add a new object named after your target. In this object two fields are required:

• "target.features_add": ["BLE"] Add the BLE feature to the target.
• "target.extra_labels_add": ["ST_BLUENRG"]: Add the BLE implementation of the ST shield to the list of the application modules.

As an example, this is the JSON bit which has to be added in the target_overrides section of mbed_app.json for a NUCLEO_F411RE board.

        "NUCLEO_F411RE": {
            "target.features_add": ["BLE"],
            "target.extra_labels_add": ["ST_BLUENRG"]
        },

Note: You can get more information about the configuration system in the documentation

Important: It is required to apply an hardware patch to the ST shield if it is used on a board with an Arduino connector. Check out https://developer.mbed.org/teams/ST/code/X_NUCLEO_IDB0XA1/ for more information.

Building and testing the examples

To build an example:

1. Clone the repository containing the collection of examples:

   $ git clone https://github.com/ARMmbed/mbed-os-example-ble.git
   

   Tip: If you don't have GitHub installed, you can download a zip file of the repository.

2. Using a command-line tool, navigate to any of the example directories, like BLE_Beacon:

   $ cd mbed-os-example-ble
   $ cd BLE_Beacon
   

3. Update the source tree:

   mbed deploy
   

4. Run the build:

   mbed compile -t <ARM | GCC_ARM> -m <YOUR_TARGET>

To run the application on your board:

1. Connect your mbed board to your computer over USB. It appears as removable storage.

2. When you run the mbed compile command, as you did above, mbed cli creates a BIN or an HEX file in a BUILD/<target-name>/<toolchain> directory under the example's directory. Drag and drop the file to the removable storage.

Exactly which executables are generated depends on the target that you have chosen. For Nordic Semiconductor targets, the following .hex files will be present:

• <module_name>.hex is the one which can be flashed to the target.
• <module_name>.elf is an ELF binary containing symbols (useful for debugging).

Note: Depending on the build process, the file which has to be flashed on a Nordic target can also be named <module_name>-combined.hex. If <module_name>-combined.hex and <module_name>.hex are present in the build directory, flash `<module_name>-combined.hex.

Note: On non Nordic targets, the file to flash can also be named <module_name>.bin. Refer to mbed-cli, mbed-os and your board vendor documentation for more informations.

Known issues

• [NUCLEO_F411RE]: Some BLE examples doesn't work with the X-NUCLEO BLE shield. See #40
• [NRF5] Impossible to debug or flash the examples with IAR: See #39