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class USBD_NCM – USB NCM network interface

This class provides a network interface over USB using the NCM (Network Control Model) protocol. The host computer sees this device as a USB Ethernet adapter and assigns it an IP address via DHCP (served by the MicroPython device).

Note

network.USBD_NCM requires a port with TinyUSB and NCM support, enabled at build time by defining MICROPY_PY_NETWORK_USBD_NCM (off by default).

Example usage:

import network

nic = network.USBD_NCM()
nic.active(True)
# wait for USB host to configure the NCM interface
while not nic.isconnected():
    pass

print(nic.ipconfig("addr4"))

Constructors

class network.USBD_NCM: Create and return a USBD_NCM object. This initialises the NCM network interface if it has not already been initialised. Only one instance exists (singleton).

Methods

USBD_NCM.active([is_active])

Activate or deactivate the network interface. Without argument returns current state as a bool.

The interface is brought up automatically before USB enumeration, so this returns True from boot.

USBD_NCM.isconnected()

Returns True if the USB host has configured the NCM interface, False otherwise.

When USB is disconnected, this returns False and network traffic stops. The interface remains registered with lwIP and can resume when the host reconnects and re-enumerates the device.

USBD_NCM.status(): Returns the link status as an integer: 1 if the interface is up, 0 otherwise.

USBD_NCM.ipconfig('param')
USBD_NCM.ipconfig(param=value, ...): See AbstractNIC.ipconfig.

USBD_NCM.ifconfig([(ip, subnet, gateway, dns)]): See AbstractNIC.ifconfig.

Notes

Link-local IP address: The device IP (169.254.x.1) is derived deterministically from the device MAC address. RFC 3927 ARP probe/announce (conflict detection) is not implemented, so if two devices happen to derive the same address on the same network segment, the conflict will go undetected.

MAC address uniqueness: The device and host-side MAC addresses are derived from the value returned by mp_hal_get_mac(). If two boards have the same hardware MAC (e.g. the port does not use a hardware UID), they will present the same network addresses and cause ARP conflicts.