Note

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Wired Network Example Explanation

Example Location

• Development board firmware path: /sdcard/examples/14-Socket/network_lan.py

• SDK source code path: src/canmv/resources/examples/14-Socket/network_lan.py

Environment Preparation

Connect a USB Ethernet adapter or USB 4G ECM/NCM network card supported by the development board to the board, and connect it to a router or network that provides DHCP. The device name of the USB LAN is dynamically assigned. The example selects the device through the logical LAN interface and does not depend on a fixed name.

Code Flow

Import Common Network Functions

from libs.Network import configure_ip, connect_network, network_device_name

• connect_network(): Selects LAN, starts DHCP, waits for IP, and sets the default uplink;

• configure_ip(): Applies static address or DHCP, and waits for the address to take effect;

• network_device_name(): Reads the actual netdev name corresponding to the current LAN.

Connect to LAN Using DHCP

a, ip = connect_network("lan")
print(a.active())
print(a.ifconfig())

a is the network.LAN object, and ip is the IPv4 address obtained after a successful wait. On RT-Smart, active() is used to query whether the interface is available, not to shut down the device. ifconfig() returns:

(IP address, subnet mask, default gateway, DNS server)

Temporarily Switch to Static Address

configure_ip(a, (
    "192.168.0.4",
    "255.255.255.0",
    "192.168.0.1",
    "8.8.8.8",
))
print(a.ifconfig())

The four values must match the actual network. The example address is for demonstration only; if the network segment or gateway does not match, network communication will be interrupted after switching.

Restore DHCP

ip = configure_ip(a, "dhcp")
print("LAN device:", network_device_name(a))
print("LAN address:", ip)

configure_ip() not only initiates DHCP but also waits for a non-zero IP, so subsequent Socket code does not need to poll ifconfig() by itself.

Query MAC Address

print(a.config("mac"))

The return value is a 6-byte MAC. When a colon-separated string is needed, you can use libs.Network.mac_address(a).

Run and Verify

1. Open /sdcard/examples/14-Socket/network_lan.py in CanMV IDE.

2. Make sure the network card and cable are connected before running the script.

3. The first ifconfig() should display the DHCP address.

4. The static address phase should display the example quadruple.

5. After restoring DHCP, LAN address should display the address assigned by the router again.

Important

The static address 192.168.0.4 may conflict with existing devices. It must be modified according to the actual network segment before formal use, or remove the static address test and keep only the DHCP part.

The Python usage of USB 4G ECM/NCM is the same as LAN. For supported modules and driver configurations, refer to EC200M-CN. For complete interfaces, see network Module API Manual.