How to implement the Bluetooth server on STM32WB55 board for both sided data exchange with smartphone ?

[AlexFj]

Looking for the either code examples (possibly simplified for understanding), or a guide for Bluetooth server implementation on a Nucleo STM32WB55 board for data reception and transmission.

The sample demo for purchased P-Nucleo STM32WB55 pack (board and dongle) with switching LED was tested and works fine. However, it's code does not seem to make it clear at all.

[Stecklo]

Basically you need to call aci_gatt_add_char() with Char_Properties = CHAR_PROP_NOTIFY, to create characteristic , then aci_gatt_update_char_value() to transmit data from server.

To receive data you need to call aci_gatt_add_char() with Char_Properties = CHAR_PROP_READ, then register handler SVCCTL_RegisterSvcHandler(service_event_handler) (you better look for implementation of the handler in the sample demo). And finally in the service_event_handler you wait for EVT_BLUE_GATT_ATTRIBUTE_MODIFIED event with Attr_Handle == your_characteristic_handle + 1

These are basics. AN5270 can help. As well as Bluetooth Core Specification

[Stecklo]

I ment CHAR_PROP_WRITE, not CHAR_PROP_READ is needed to recieve data

[Stecklo]

You could also make use of AN5289. ​It is roughly a description/guide of sample demo

[AlexFj]

Thank you for the response. But how do I initiate the Bluetooth on the WB55 board in the first place ? If using the STM32cubeMX / IDE, i assume the corresponding code should be automatically generated by enabling the Connectivity->RF option (as for UART for exmaple). RF activation, however, returns "Warning: stm32cubemx does not support the configuration of this mode of this ip. However, this IP can be configured manually.", generates empty MX_RF_Init() function in the main code and ends there.

[Stecklo]

Yes, that's confusing. You need to activate Connectivity->RF so that RF pin is configured properly. To generate BLE code you need to activate Middlewares->STMWPAN. And I recommend you to activate P2P_server in STMWPAN settings. At least until you figure out how to make everything work.

[AlexFj]

Okey, so BT is being activated in STMWPAN mode. Apparently it is using several side source files called in APPE_Init(); function. (BT requires functions of the Sequencer and LPM, which by default are not being recognized (app_ble and app_entry are missing the corresponding SEQ and LPM functions - solved by moving sequencer and lpm source and header files from Utility folder to Core->Src and Inc accordingly).

Wierd happens when the code is being build, debugged and uploaded without any errors, but apparently crashes somewhere inside the APPE_Init() function after running on a board - process is either not returning from the APPE_Init function, or stops right after. Board itself doesn't show up for another BT devices either. What may be an issue in this case ?

[Stecklo]

Moving files is not a wise desision. If you are using TrueStudio or CubeIDE the best way is:

• in Project Explorer right click on any source folder (for examlple Core->Src or Middlewares)
• New->File
• Advanced >>
• Link to file in file system
• Browse to the desired source file

That will create a link to the library folder and your project will be more flexible in case of library update

You also need to add an include path Project->Properties->C/C++ general->Includes->Add

[Stecklo]

Read this article to enable sending debug info from board to PC