Atom DTU NBIoT

This is the driver library for the ATOM DTU NBIoT to accept and send data from the DTU NBIoT.

Support the following products:

Note

Please ensure that the device supports the NB-IoT frequency bands in your area before use.

Note

Please ensure that the firmware version of SIM7020 is greater than or equal to 1752B12SIM7020C.

can be used to check the firmware version.

UiFlow2 Example

NBIoT HTTP Example

Open the atoms3_base_nbiot_http_example.m5f2 project in UiFlow2.

This example shows how to send HTTP request using the Atom DTU NBIoT.

UiFlow2 Code Block:

Example output:

Output of received NBIoT message data via serial port.

MQTT Example

Open the atoms3_base_nbiot_mqtt_example.m5f2 project in UiFlow2.

This example shows how to send MQTT message using the Atom DTU NBIoT.

UiFlow2 Code Block:

Example output:

Output of received NBIoT message data on screen.

MicroPython Example

NBIoT HTTP Example

This example shows how to send HTTP request using the Atom DTU NBIoT.

MicroPython Code Block:

# SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
from hardware import UART
from base import AtomDTUNBIoT
from base import AtomRS485


uart2 = None
base_rs485 = None
base_nbiot = None
base_nbiot_http_req = None


def setup():
    global uart2, base_rs485, base_nbiot, base_nbiot_http_req

    M5.begin()
    Widgets.fillScreen(0x000000)

    uart2 = UART(2, baudrate=115200, bits=8, parity=None, stop=1, tx=5, rx=6)
    base_rs485 = AtomRS485(
        1,
        baudrate=115200,
        bits=8,
        parity=None,
        stop=1,
        tx=7,
        rx=8,
        txbuf=256,
        rxbuf=256,
        timeout=0,
        timeout_char=0,
        invert=0,
        flow=0,
    )
    base_nbiot = AtomDTUNBIoT(uart2, verbose=False)
    base_nbiot.connect(apn="cmnbiot")
    while not (base_nbiot.isconnected()):
        pass
    base_nbiot_http_req = base_nbiot.post(
        "http://httpbin.org/post",
        json={"message": "Hello from M5Stack!", "status": "active"},
        headers={
            "Content-Type": "application/json",
            "Custom-Header": "MyHeaderValue",
        },
    )
    print((str("status code: ") + str((base_nbiot_http_req.status_code))))
    print((str("content: ") + str((base_nbiot_http_req.content))))


def loop():
    global uart2, base_rs485, base_nbiot, base_nbiot_http_req
    M5.update()


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:

Output of received NBIoT message data via serial port.

MQTT Example

This example shows how to send MQTT message using the Atom DTU NBIoT.

MicroPython Code Block:

# SPDX-FileCopyrightText: 2026 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT
import os, sys, io
import M5
from M5 import *
from base import AtomDTUNBIoT
from hardware import UART
from base import AtomRS485


label0 = None
base_nbiot = None
uart2 = None
base_rs485 = None
base_nbiot_mqtt = None


def base_nbiot_testtopic_a_event(data):
    global label0, base_nbiot, uart2, base_rs485, base_nbiot_mqtt
    label0.setText(str(data[1]))


def setup():
    global label0, base_nbiot, uart2, base_rs485, base_nbiot_mqtt

    M5.begin()
    Widgets.fillScreen(0x000000)
    label0 = Widgets.Label("label0", 4, 6, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)

    uart2 = UART(2, baudrate=115200, bits=8, parity=None, stop=1, tx=5, rx=6)
    base_rs485 = AtomRS485(
        1,
        baudrate=115200,
        bits=8,
        parity=None,
        stop=1,
        tx=7,
        rx=8,
        txbuf=256,
        rxbuf=256,
        timeout=0,
        timeout_char=0,
        invert=0,
        flow=0,
    )
    base_nbiot = AtomDTUNBIoT(uart2, verbose=False)
    base_nbiot.connect(apn="cmnbiot")
    while not (base_nbiot.isconnected()):
        pass
    base_nbiot_mqtt = base_nbiot.MQTTClient(
        "uiflow2-client", "mqtt.m5stack.com", port=1883, user="", password="", keepalive=0
    )
    base_nbiot_mqtt.connect(clean_session=False)
    base_nbiot_mqtt.subscribe("testtopic/a", base_nbiot_testtopic_a_event, qos=0)


def loop():
    global label0, base_nbiot, uart2, base_rs485, base_nbiot_mqtt
    M5.update()
    base_nbiot_mqtt.check_msg()


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:

Output of received NBIoT message data on screen.

API

AtomDTUNBIoT

class base.dtu_nbiot.AtomDTUNBIoT(uart, verbose=False)

Bases: SIM7020

Create an AtomDTUNBIoT object.

Parameters:

uart (machine.UART) – The UART object to use.
verbose (bool) – Whether to print debug information.

UiFlow2 Code Block:

MicroPython Code Block:

from base import AtomDTUNBIoT
from hardware import UART

uart0 = UART(2, baudrate=115200, bits=8, parity=None, stop=1, tx=22, rx=19)
dtu_nbiot = AtomDTUNBIoT(uart0, verbose=False)

Note

See NBIOTUnit for more details.

AtomRS485

Note

See AtomRS485 for more details.