by Danny Staple

In chapter 11 of Robotics at Home with Raspberry Pi Pico, I introduce the asyncio library, and get this installed on the Raspberry Pi Pico. This is a library that lets you schedule multiple tasks on the Pico. They don’t run in parallel, so much as hand control over to different processes when they are waiting for something.

Some readers have had a little trouble with this.

First, I suggest installing it with circup, and still consider this the best way to manage the library in CircuitPython.

But let’s look at debugging what you do have.

  1. With the battery power turned off, plug your robot in via USB. Next you need a repl (I’ve used Thonny in CircuitPython mode). Let’s ensure it works:

    >>> import asyncio
  2. We can now try check for the symbol:

    >>> asyncio.create_task
    <function create_task at 0x2003a3a0>

    Note the address will likely be different, but the overall shape should be the same. If you do not see this, we need to find out what is going on with asyncio.

  3. The python dir command shows the contents of a symbol, in this instance the asyncio module:

    >>> dir(asyncio)
    ['__class__', '__getattr__', '__name__', '__file__', '__path__', '__version__', 'CancelledError', 'Event', 'Task', 'TaskQueue', 'TimeoutError', 'event', 'run', 'select', 'sleep', 'sys', 'traceback', 'core', '__repo__', 'funcs', 'wait_for', 'gather', 'lock', 'Lock', '_attrs', 'ticks_diff', 'ticks_add', 'ticks', 'SingletonGenerator', 'sleep_ms', 'IOQueue', 'create_task', 'run_until_complete', 'Loop', 'get_event_loop', 'current_task', 'new_event_loop', 'wait_for_ms']

    What we see here is a list of methods, classes and other symbols in the asyncio library.

  4. If this is not what you see, what I suggest now is to use circup to bump this library to the most recent version. On your computer, run:

    circup update

    You may need a recent version of circup for this to work. Going back to your original repl, use ctrl-d to reboot the Pico, and try again from step 1 onwards.

If this still does not work, please let me know. I’m happy to help you debug this.