Ports

The port is the serial path a device is reached on, such as /dev/ttyACM0 on Linux or /dev/cu.usbmodem1101 on macOS. A project’s port is stored in its .micropython file:

PORT=auto

Value	Meaning
auto	Use the first USB serial device mpremote finds. The default.
/dev/ttyACM0	Always use this port
id:<serial>	Use the device with this USB serial number, whichever port it’s on

auto is fine with one device plugged in. With several, pick one: a fixed path, or id: if the path changes between plug-ins. You can also set a default in setup() with the port option; a project’s .micropython file overrides it.

:MP set_port

Shows a list of ports to choose from: auto, then every serial port mpremote can see. If mpremote sees none, it lists likely serial paths such as /dev/ttyACM* instead. The choice is used straight away and saved in the project’s .micropython file. Outside a project it’s used until you quit Neovim, with a warning that there’s no .micropython file to save it in.

To use id:<serial>, which isn’t in the list, edit .micropython yourself. :MP list_devices shows each device’s serial number. The plugin reads .micropython when Neovim starts, so restart Neovim after editing it by hand.

:MP list_devices

Lists every serial device that’s connected, with its port, serial number and manufacturer, in a notification. It shows all serial devices mpremote can see, not only ones running MicroPython.