UDP Client

UiFlow2 Example

simple client

Open the cores3_udp_client_example.m5f2 project in UiFlow2.

This example creates a UDP client that sends data to a server.

UiFlow2 Code Block:

Example output:

None

MicroPython Example

sample client

This example creates a UDP client that sends data to a server.

MicroPython Code Block:

# SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
import network
import socket
import time


title0 = None
label0 = None
label1 = None
label2 = None
label3 = None
label4 = None
label5 = None
label6 = None
label7 = None
label8 = None
label9 = None
wlan = None
udpc = None


count = None
resp = None


def setup():
    global \
        title0, \
        label0, \
        label1, \
        label2, \
        label3, \
        label4, \
        label5, \
        label6, \
        label7, \
        label8, \
        label9, \
        wlan, \
        udpc, \
        count, \
        resp

    M5.begin()
    Widgets.fillScreen(0x222222)
    title0 = Widgets.Title("UDP Clinet", 3, 0xFFFFFF, 0x0000FF, Widgets.FONTS.DejaVu24)
    label0 = Widgets.Label("Local IP:", 4, 32, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label1 = Widgets.Label("Server IP:", 4, 60, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label2 = Widgets.Label("Server Port:", 4, 88, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label3 = Widgets.Label("Send:", 4, 116, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label4 = Widgets.Label("Recv:", 4, 144, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label5 = Widgets.Label("label5", 136, 32, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label6 = Widgets.Label("label6", 136, 60, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label7 = Widgets.Label("label7", 136, 88, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label8 = Widgets.Label("label8", 136, 118, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label9 = Widgets.Label("label9", 136, 144, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)

    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    udpc = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    udpc.connect(("192.168.8.236", 8000))
    count = 0
    label5.setText(str(wlan.ifconfig()[0]))
    label6.setText(str("192.168.8.236"))
    label7.setText(str("8000"))


def loop():
    global \
        title0, \
        label0, \
        label1, \
        label2, \
        label3, \
        label4, \
        label5, \
        label6, \
        label7, \
        label8, \
        label9, \
        wlan, \
        udpc, \
        count, \
        resp
    M5.update()
    udpc.send(str(count))
    time.sleep_ms(100)
    resp = udpc.recv(1024)
    label8.setText(str(count))
    label9.setText(str(resp))
    count = (count if isinstance(count, (int, float)) else 0) + 1
    time.sleep(1)


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            from utility import print_error_msg

            print_error_msg(e)
        except ImportError:
            print("please update to latest firmware")

Example output:

None

API

socket.socket()

socket.connect(address)

Create a socket object and connect to the server.

Parameters:: address (tuple) – A tuple containing the server IP address and port number.
Returns:: A socket object.
Return type:: socket.socket

UiFlow2 Code Block:

MicroPython Code Block:

import socket

udpc = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
udpc.connect(('192.168.8.236', 8000))

socket.close()

Close the socket connection.

UiFlow2 Code Block:

MicroPython Code Block:

udpc.close()

socket.recv(bufsize)

Receive data from the socket.

Parameters:: bufsize (int) – The maximum amount of data to be received at once.
Returns:: The received data.
Return type:: bytes

UiFlow2 Code Block:

MicroPython Code Block:

data = udpc.recv(1024)
print(data)

socket.read()

Read data from the socket.

Returns:: The received data.
Return type:: bytes

UiFlow2 Code Block:

MicroPython Code Block:

data = udpc.read()
print(data)

socket.send(data)

Send data to the socket. The socket must be connected to a remote socket.

Parameters:: data (bytes | str) – The data to be sent.
Returns:: The number of bytes sent.
Return type:: int

UiFlow2 Code Block:

MicroPython Code Block:

udpc.send(b'Hello, World!')
udpc.send('Hello, World!')

socket.write(data)

Write the buffer of bytes to the socket. This function will try to write all data to a socket (no “short writes”). This may be not possible with a non-blocking socket though, and returned value will be less than the length of buf.

Parameters:: data (bytes | str) – The data to be sent.
Returns:: The number of bytes sent.
Return type:: int

UiFlow2 Code Block:

MicroPython Code Block:

udpc.write(b'Hello, World!')
udpc.write('Hello, World!')

socket.setsockopt(level, optname, value)

Set the value of the given socket option. The needed symbolic constants are defined in the socket module (SO_* etc.). The value can be an integer or a bytes-like object representing a buffer.

Parameters:

level (int) – The level at which the option is defined.
optname (int) – The name of the option to set.
value – The value to set for the option.

UiFlow2 Code Block:

MicroPython Code Block:

udpc.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 0)
udpc.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)