RT Classic Bluetooth Application Framework

rt_bt_app is a reusable classic‑Bluetooth application framework middleware. It extracts repetitive code blocks required by every Bluetooth‑based application, including event‑thread management, event routing, command dispatching, shell command processing and pluggable profile modules, into an out‑of‑the‑box independent component.

With this framework, application developers only need to write a self-registering service file for each Bluetooth profile (HFP, SPP, A2DP, etc.), focusing on business logic without worrying about event threads, message queues, or command parsing, and without directly calling low-level protocol stack interfaces.

For a complete end-to-end example, see example/rt_device/bt, which includes a full HFP implementation and an SPP skeleton for educational purposes.

I. What Problems Does It Solve

When driving Bluetooth directly with the RT-Thread device framework (rt_device_find("bt_device") + rt_device_control + event callbacks), every project encounters the same challenges:

Challenge	Framework Solution
Events and commands scattered by profile; adding a new profile requires modifying large `switch-case` blocks	Plugin-based service registry: Automatic routing by event/command high byte; adding a profile only requires one self-registering file with zero changes to the core
Each project needs to implement its own debug commands	Built-in unified `bt <service> <cmd>` three-level shell command
Manual device opening and name setting after stack ready in every project	Core built-in common event handler that automatically opens the device and sets the local name when stack becomes ready

II. Position in the SDK

Application / Service Plugins  (bt_srv_hfp.c / bt_srv_spp.c ...)   ← Profile business logic, self-registered
        │  Depends on rt_bt_app.h framework contract
        ▼
rt_bt_app   【This Middleware】Event thread / routing / command dispatch / shell
        │  rt_device_find / rt_device_control / register notify callback
        ▼
bt_device        An RT-Thread device (only implements control)
        │  Registered by customer/peripherals/bluetooth/bt_sifli
        ▼
bt_sifli driver  Dispatches BT_CONTROL_* by cmd>>8, reports BT_EVENT_*
        ▼
SiFli Bluetooth Stack (bts2 / sibles)

III. Directory Structure

middleware/rt_bt_app/
├── rt_bt_app.h        Public API interface
├── rt_bt_app.c        Core implementation
├── rt_bt_app_cmd.c    Finsh shell commands
├── Kconfig            Configuration file
└── SConscript         Build script

IV. How to Use

Step 1: Enable CONFIG_BT_USING_RT_BT_APP=y in proj.conf, and enable profile driver macros as needed (e.g., CONFIG_BT_USING_HF=y, CONFIG_BT_USING_SPP=y).

Step 2: Initialize the framework in main, then enable the protocol stack:

#include "rt_bt_app.h"

int main(void)
{
    if (rt_bt_app_init() != RT_EOK)
    {
        LOG_E("BT core init failed");
    }

    sifli_ble_enable();   
    while (1)
    {
        rt_thread_mdelay(10000);
    }
    return 0;
}

Note: LOG_E requires #include <rtdbg.h> and the DBG_TAG/DBG_LVL macros. See the full example in example/rt_device/bt/src/main.c.

Step 3: Add the service plugins you need (bt_srv_xxx.c) to the project build. Services self-register via RT_BT_SERVICE_REGISTER without manual registration in main. Refer to examples in example/rt_device/bt/src/services.

After startup, use the bt command to control:

bt            # List all services
bt hfp        # List all HFP subcommands