micro:bit v2 does not support Ctrl+C interrupt

[colinvail6]

CircuitPython version and board name

Adafruit CircuitPython 10.1.3 on 2026-02-20; micro:bit v2 with nRF52833

Code/REPL

Ctrl+C (in serial connection)

Behavior

micro:bit v2 does not respond to Ctrl+C, even though the action was sent.

Description

• When the Ctrl+C signal is sent to the micro:bit v2, the yellow data LED blinks, but nothing else happens

Additional information

Putting the micro:bit v2 into safe mode interrupts it.

[dhalbert]

Which serial program are you using, on what operating system and version?

[colinvail6]

I have tried both PuTTY and Thonny on Windows 11. Neither of them have been able to interrupt the micro:bit.

[colinvail6]

Also, for Windows, do mBed-running devices need USB drivers?

[dhalbert]

Also, for Windows, do mBed-running devices need USB drivers?

No, that should not be necessary for Windows 10 and later. Windows 10 came with a universal USB CDC driver.

[dhalbert]

I reproduced this with tio and also with Thonny. I also went all the way back to the first build we have: https://adafruit-circuit-python.s3.amazonaws.com/bin/microbit_v2/en_US/adafruit-circuitpython-microbit_v2-en_US-7.0.0-alpha.5.combined.hex, and it does not work for that build either. So it never worked (!). I tried various builds in between as well.

[dhalbert]

I looked at this a little bit and this is not something that is just a bug that is easy to fix. The REPL console is supported by sending data over a busio.UART() internally. There is no support right now to monitor that connection for ctrl-C interrupts asynchronously.

Espressif boards that use special serial console connections (CIRCUITPY_ESP_USB_SERIAL_JTAG boards like ESP32) do this differently, and have an interrupt handler for incoming UART bytes that checks for ctrl-C.

It would be possible to do this, but right now this is the only board that needs it.
The micro:bit V2 was added in #5002 and was described as a "BLE-only" board. It looks like the File Glider app still works with it to do file manipulation over BLE. There is no BLE REPL connection.

If you are connected via serial, you can do a hard interrupt by sending a serial break (e.g., Ctrl-t b in tio), which will restart CircuitPython.

I'll put this on the long-term queue, but it's not a high priority right now - sorry.