CircuitPython Error on Catalina -- "Port must be configured before it can be used"

[txoof]

• CircuitPython Kernel version: 7.19.0
• Python version: 3.8.6
• Operating System: Mac OS Catalina 10.15.7
• Board-ID: SAMD51G19A-Itsy-v0
• Board boot_out.txt: Adafruit CircuitPython 6.0.1 on 2020-12-28; Adafruit ItsyBitsy M4 Express with samd51g19
• UF2 Bootloader v3.10.0 SFHWRO

Description

When following the Adafruit Jupyter Circuit Python Guide, Jupyter fails to connect to the kernel/board with the error Port must be configured before it can be used displayed in the terminal

What I Did

• cloned this repository
• ran:

       $ python3 setup.py install
       $ cd circuitpython_kernel
       $ python3 -m circuitpython_kernel.install
  

• Board is connected via known-good USB cable
• Board neo-pixel is blinking green
• Board appears as USB Drive "CIRCUITPY" in finder

Trouble Shooting Attempts:

Attempt: Restart Jupyter

• Result:
  - Jupyter output: A connection to the notebook server could not be established. The notebook will continue trying to reconnect. Check your network connection or notebook server configuration.
  - Terminal Output: (repeats 5 times)

[I 11:09:50.381 NotebookApp] KernelRestarter: restarting kernel (1/5), new random ports
Traceback (most recent call last):
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/circuitpython_kernel/__main__.py", line 4, in <module>
    IPKernelApp.launch_instance(kernel_class=CircuitPyKernel)
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/traitlets/config/application.py", line 844, in launch_instance
    app.initialize(argv)
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/traitlets/config/application.py", line 87, in inner
    return method(app, *args, **kwargs)
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/ipykernel/kernelapp.py", line 582, in initialize
    self.init_kernel()
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/ipykernel/kernelapp.py", line 444, in init_kernel
    kernel = kernel_factory(parent=self, session=self.session,
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/traitlets/config/configurable.py", line 537, in instance
    inst = cls(*args, **kwargs)
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/circuitpython_kernel/kernel.py", line 37, in __init__
    self.serial = connect()
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/circuitpython_kernel/board.py", line 58, in connect
    s.open()
  File "/Users/aaronciuffo/.pyenv/versions/3.8.6/Python.framework/Versions/3.8/lib/python3.8/site-packages/serial/serialposix.py", line 316, in open
    raise SerialException("Port must be configured before it can be used.")
serial.serialutil.SerialException: Port must be configured before it can be used.
... Repeats 5 times ...
[W 11:15:48.289 NotebookApp] KernelRestarter: restart failed
[W 11:15:48.289 NotebookApp] Kernel 3c7b0cdf-538d-481c-b159-7fa42722b61b died, removing from map.

Attempt: Reset M4 Board and restart kernel

• Result: Same as above

Attempt: Reset unplug board and restart kernel

• Result: Same as above

[txoof]

Additional Information:

• REPL/Serial interface works through MU-Editor

[brentru]

@txoof I still run catalina and will attempt to replicate. Thanks for the robust writeup.

I haven't used this kernel for a while, it's possible the serialutil module has changed since.

[txoof]

@brentru
I don't know if this is at all relevant, but I'm running python out of a pyenv virtual environment.