ELEC-C7222 Library Examples

ELEC-C7222 Library Examples: Security Manager Example ELEC-C7222 Library Examples: Custom Service READ + WRITE Example ELEC-C7222 Library Examples: Custom Service NOTIFY Example

This document describes the example applications shipped with libs/elec_c7222 and how to build them. The examples are intended for teaching and validation of the library on Raspberry Pico W platforms.

Overview

The examples are organized under libs/elec_c7222/examples and are built through a common CMake selection mechanism. When C7222_EXAMPLES_BUILD is ON, all example targets are created and can be selected in your build/IDE.

Examples currently provided:

• FreeRTOS board validation (freertos-board-example): exercises GPIO, LEDs, buttons, interrupts, and FreeRTOS primitives using the c7222_pico_w_board API. Intended for first-time hardware validation.
• FreeRTOS device C++ example (freertos-device-cpp): demonstrates C++ device wrappers, SafeLed/ButtonEvent helpers, and ISR-to-task dispatch using FreeRTOS wrapper classes (FreeRtosTimer, FreeRtosTask).
• BLE GAP example (ble/gap): focuses on GAP only. It initializes the BLE stack, configures advertising, registers a GAP event handler, and periodically updates manufacturer data using FreeRTOS wrapper classes (FreeRtosTask).
• BLE GATT server example (ble/gatt-server): demonstrates an AttributeServer with a GATT profile, Security Manager configuration, characteristic discovery, and periodic temperature updates using FreeRTOS wrapper classes (FreeRtosTask, FreeRtosTimer).

Build selection model

The build system creates an interface library per example (under libs/elec_c7222/examples) and the top-level CMake assembles the list when C7222_EXAMPLES_BUILD is ON. Each example target carries metadata properties such as TARGET_NAME, TARGET_PATH, and optional GATT_FILES for BLE apps.

Key options (declared in CMakeLists.txt):

• C7222_EXAMPLES_BUILD (BOOL): enable example build targets.
• C7222_ENABLE_BLE (BOOL): enable BLE support; required for BLE examples.
• APP_NAME (STRING): application name for the final executable when examples are not built.

When C7222_EXAMPLES_BUILD is OFF, the build falls back to sources from APP_SOURCE_DIR (default behavior). When it is ON, all example targets are available and you can select the desired executable in your IDE or via CMake target selection.

How to configure and build

Use CMake presets or pass -D options manually. The following example configures and builds all examples, then builds the BLE GAP target:

cmake -S . -B build \
  -DC7222_EXAMPLES_BUILD=ON \
  -DC7222_ENABLE_BLE=ON
 
cmake --build build --target example-ble-gap

Example build for the GATT server example:

cmake --build build --target example-ble-gatt-server

Example build for the FreeRTOS board example:

cmake --build build --target example-freertos-board
 
Example build for the FreeRTOS device C++ example:

bash cmake –build build –target example-freertos-device-cpp

Clearing cache and rebuilding

CMake caches configuration in the build directory. To switch examples or change options cleanly, remove the build directory or the cache file, then reconfigure.

Option A: remove the build directory:

rm -rf build
cmake -S . -B build -D<options...>
cmake --build build

Option B: remove only the cache file:

rm -f build/CMakeCache.txt
cmake -S . -B build -D<options...>
cmake --build build

If you use CMake Tools in VS Code, you can also run CMake: Delete Cache and Reconfigure from the command palette, then rebuild.

Using CMake Presets

This project already includes CMakePresets.json at the repository root. You can modify that file to add or adjust presets as needed, then select them in VS Code or on the command line.

Example preset for the BLE GAP example:

{
  "name": "ble-gap-example",
  "displayName": "BLE GAP Example",
  "generator": "Ninja",
  "binaryDir": "${sourceDir}/build/ble-gap",
  "cacheVariables": {
    "C7222_EXAMPLES_BUILD": "ON",
    "C7222_ENABLE_BLE": "ON"
  }
}

Example preset for the BLE GATT server example:

{
  "name": "ble-gatt-server-example",
  "displayName": "BLE GATT Server Example",
  "generator": "Ninja",
  "binaryDir": "${sourceDir}/build/ble-gatt-server",
  "cacheVariables": {
    "C7222_EXAMPLES_BUILD": "ON",
    "C7222_ENABLE_BLE": "ON"
  }
}

Example preset for the FreeRTOS board example:

{
  "name": "freertos-board-example",
  "displayName": "FreeRTOS Board Example",
  "generator": "Ninja",
  "binaryDir": "${sourceDir}/build/freertos-board",
  "cacheVariables": {
    "C7222_EXAMPLES_BUILD": "ON"
  }
}

Creating new presets

To add a new preset:

1. Copy one of the example blocks above.
2. Give it a unique name and displayName.
3. Pick a unique binaryDir so builds do not collide.
4. Set C7222_ENABLE_BLE to ON for BLE examples.
5. Optionally set APP_NAME to label the output ELF/UF2.

In VS Code, select a preset via CMake: Select Configure Preset, then run CMake: Configure and CMake: Build.