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I have correctly got a microbit working with serial communication via COM port USB.

My aim is to use COM over bluetooth to do the same.

Steps I have taken:

  1. (on windows 10) bluetooth settings -> more bluetooth settings -> COM ports -> add -> incoming
  2. in device manager changed the baud rate to match that of the microbit (115,200)
  3. paired and connected to the microbit
  4. tried to write to both the serial and uart bluetooth connection from the microbit to the PC (using a flashed python script)
  5. using Tera Term, setup -> serial port... -> COM(number - in my case 4), with all necessary values (including 115,200 baud rate)

After doing all of these, I see no incoming message on Tera Term. Have I missed anything?

Joe Moore
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    I don't think this is possible for a couple of reasons. 1) The micro:bit micropython only has [limited support](https://microbit-micropython.readthedocs.io/en/v2-docs/ble.html) for BLE. 2) Bluetooth serial is a "classic" profile and micro:bit only uses BLE. The UART profile is a custom profile so I would not expect the PC to know how to use it by default. You would need to use MakeCode to use [BLE UART](https://support.microbit.org/support/solutions/articles/19000062330-using-the-micro-bit-bluetooth-low-energy-uart-serial-over-bluetooth-) – ukBaz Dec 31 '22 at 07:07

2 Answers2

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This is not directly possible via BLE UART communication because it uses different protocols (as mentioned above by ukBaz).

You are able to, however, communicate via custom BLE libraries such as bleak.

Bleak has some good examples on its github repo of how to scan GATT characteristics and services to find the TX and RX characteristics of your BLE device.

From there you're able to connect to the microbit directly over bluetooth and read and write to it's GATT table and not using the proprietary BLE protocols etc.

I'll make a tutorial at some point and link it back here when it's done.

Joe Moore
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1

I created kaspersmicrobit to make it easier to connect to the BLE services of a micro:bit using python. As ukBaz pointed out, one of the GATT services that can be enabled is the uart service and with help of kaspersmicrobit, you can use it like this:

def print_received_string(string: str):
    print(f"Received from microbit: '{string}'")


with KaspersMicrobit(MICROBIT_BLUETOOTH_ADDRESS) as microbit:
    # listen for strings sent by the microbit
    microbit.uart.receive_string(print_received_string)

    # send a string to the microbit 
    microbit.uart.send_string("Hello micro:bit!\n")

    time.sleep(25)
janickr
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