Micro Bit example Updated +Created
Raspberry Pi Pico W UART Updated +Created
You can connect form an Ubuntu 22.04 host as:
screen /dev/ttyACM0 115200
When in screen, you can Ctrl + C to kill main.py, and then execution stops and you are left in a Python shell. From there:
  • Ctrl + D: reboots
  • Ctrl + A K: kills the GNU screen window. Execution continues normally
but be aware of: Raspberry Pi Pico W freezes a few seconds after after screen disconnects from UART.
Universal asynchronous receiver-transmitter Updated +Created
A good project to see UARTs at work in all their beauty is to connect two Raspberry Pis via UART, and then:
Part of the beauty of this is that you can just connect both boards directly manually with a few wire-to-wire connections with simple jump wire. Its simplicity is just quite refreshing. Sure, you could do something like that for any physical layer link presumably...
Remember that you can only have one GNU screen connected at a time or else they will mess each other up: unix.stackexchange.com/questions/93892/why-is-screen-is-terminating-without-root/367549#367549
On Ubuntu 22.04 you can screen without sudo by adding yourself to the dialout group with:
sudo usermod -a -G dialout $USER