Note

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UDP Client Example Explanation

Example Location

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

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

The clinet in the filename follows the actual spelling used in the current firmware and source code directories. This example uses the development board as a UDP sender, continuously sending 10 datagrams to the computer.

Preparation Before Running

First, start a UDP debugging tool on the computer and listen on a port, then modify the network parameters and target address in the script:

NETWORK_TYPE = "wifi_sta"
WLAN_DEVICE = "auto"
WIFI_SSID = "TEST"
WIFI_PASSWORD = "12345678"
NETWORK_TIMEOUT = 20

ai = socket.getaddrinfo("192.168.1.110", 8080)

Change 192.168.1.110 to the IP that allows communication between the computer and the development board, change 8080 to the UDP listening port on the computer side, and allow that UDP port through the firewall.

Code Flow

Connect to the Network

netif, _ = connect_network(...)

The common network library waits for the interface to obtain an IP and selects the default uplink interface.

Resolve the Target Address and Create a UDP Socket

addr = socket.getaddrinfo("192.168.1.110", 8080)[0][-1]
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

SOCK_DGRAM indicates UDP. Unlike TCP, it does not need to establish a connection beforehand; each send specifies the target address directly.

Send 10 Datagrams

for i in range(10):
    message = "K230 udp client send test {0} \r\n".format(i)
    s.sendto(message, addr)
    time.sleep(0.2)

Each sendto() corresponds to an independent UDP datagram, and the receiving end can preserve the datagram boundaries. UDP does not guarantee delivery, ordering, or deduplication; application-layer acknowledgment and retransmission are required when reliability is needed.

Close the Socket

After the script finishes sending, it waits for 1 second, closes the Socket, and prints end. This example only sends data and does not call recvfrom(), so it will not read the server’s reply.

Running and Verification

1. First, start the UDP receiving tool on the computer.

2. Run /sdcard/examples/14-Socket/udp_clinet.py.

3. The computer should receive 10 datagrams with sequence numbers 0 to 9.

4. If the serial port shows the message was sent successfully but the computer didn’t receive it, focus on checking the target IP, UDP port, firewall, and the client isolation settings of the Wi-Fi hotspot.