Arm Mbed and Pelion Device Management support forum

BLE assignment of pins


We have developed our own board using STM32L496RET6 and and RN4871-V/RM118 for Bluetooth.

Everything works fine, we can stream data from our board using Transparent UART (setting SS,40 on the RN4871 in command mode) and we can see data reception when using phone bluetooth terminals. Our problem is that we are trying to make a mobile phone application which receives this data and manipulates it. We plan on using Flutter to develop our application. We are slowly starting to realise that we might not be able to do this using the transparent UART and we might need to switch to a GATT Server.

The problem with that is that all the MBed examples we find using Gatt Server are written for specific development boards which already have a BLE module connected. How do we go about connecting an external BLE to our board? It currently uses RX/TX pins connected to our processor TX/RX. Is it just a matter of reassigning the pins of the MBed example to match our pins? If so, how do we overwrite the existing pin assignment?

Thank you,

1 Like

Interested in the answer as well!

Is this your own custom target?

If no,
You should be able to override the PinNames.h file for that target.
Off hand I don’t know the cleanest way to do so.
Probably a target-overrides in your mbed_app.json file.

If it is a custom target,
Check the manual on how to use custom_targets.h and create your own pinNames.h file based on the original.
There is also a more complete guide to making custom targets in the works if not already released. I last saw it as PR in the Github repository that tracks the documentation sources.

I’m traveling or I would link you to the relevant information.