NB-IoT2 Unit

The NB-IOT2 Unit is a wireless communication module suitable for global Cat-NB frequency bands. It features an integrated SIM7028 communication module, utilizing serial communication (controlled via AT commands).

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 SIM7028 is greater than or equal to 2110B07SIM7028.

can be used to check the firmware version.

UiFlow2 Example

NBIoT HTTP Example

Open the cores3_unit_nbiot2_http_example.m5f2 project in UiFlow2.

This example shows how to send HTTP request using the NBIoT2 Unit.

click Send button to send HTTP request. Response data will be printed in the textarea.

UiFlow2 Code Block:

Example output:

Output of received NBIoT message data on screen.

MQTT Example

Open the cores3_unit_nbiot2_mqtt_example.m5f2 project in UiFlow2.

This example shows how to send MQTT message using the NBIoT2 Unit.

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 NBIoT2 Unit.

MicroPython Code Block:

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

import os, sys, io
import M5
from M5 import *
import m5ui
import lvgl as lv
from unit import NBIOT2Unit


page0 = None
label0 = None
label1 = None
button0 = None
textarea0 = None
textarea1 = None
nbiot2_0_http_req = None
nbiot2_0 = None


def button0_short_clicked_event(event_struct):
    global page0, label0, label1, button0, textarea0, textarea1, nbiot2_0_http_req, nbiot2_0
    nbiot2_0_http_req = nbiot2_0.post(
        "http://httpbin.org/post",
        json={"message": "Hello from M5Stack!", "status": "active"},
        headers={
            "Content-Type": "application/json",
            "Custom-Header": "MyHeaderValue",
        },
    )
    textarea1.set_text(str(nbiot2_0_http_req.text))


def button0_event_handler(event_struct):
    global page0, label0, label1, button0, textarea0, textarea1, nbiot2_0_http_req, nbiot2_0
    event = event_struct.code
    if event == lv.EVENT.SHORT_CLICKED and True:
        button0_short_clicked_event(event_struct)
    return


def setup():
    global page0, label0, label1, button0, textarea0, textarea1, nbiot2_0_http_req, nbiot2_0

    M5.begin()
    Widgets.setRotation(1)
    m5ui.init()
    page0 = m5ui.M5Page(bg_c=0xFFFFFF)
    textarea0 = m5ui.M5TextArea(
        text="http://httpbin.org/post",
        placeholder="Placeholder...",
        x=46,
        y=10,
        w=195,
        h=21,
        font=lv.font_montserrat_14,
        bg_c=0xFFFFFF,
        border_c=0xE0E0E0,
        text_c=0x212121,
        parent=page0,
    )
    textarea1 = m5ui.M5TextArea(
        text="textarea1",
        placeholder="Placeholder...",
        x=10,
        y=68,
        w=300,
        h=162,
        font=lv.font_montserrat_14,
        bg_c=0xFFFFFF,
        border_c=0xE0E0E0,
        text_c=0x212121,
        parent=page0,
    )
    label0 = m5ui.M5Label(
        "url:",
        x=10,
        y=10,
        text_c=0x000000,
        bg_c=0xFFFFFF,
        bg_opa=0,
        font=lv.font_montserrat_16,
        parent=page0,
    )
    label1 = m5ui.M5Label(
        "Response",
        x=10,
        y=44,
        text_c=0x000000,
        bg_c=0xFFFFFF,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )
    button0 = m5ui.M5Button(
        text="Send",
        x=251,
        y=10,
        bg_c=0x2196F3,
        text_c=0xFFFFFF,
        font=lv.font_montserrat_14,
        parent=page0,
    )

    button0.add_event_cb(button0_event_handler, lv.EVENT.ALL, None)

    nbiot2_0 = NBIOT2Unit(1, port=(18, 17), verbose=False)
    page0.screen_load()
    nbiot2_0.connect(apn="cmnbiot")
    while not (nbiot2_0.isconnected()):
        pass
    textarea0.set_one_line(True)


def loop():
    global page0, label0, label1, button0, textarea0, textarea1, nbiot2_0_http_req, nbiot2_0
    M5.update()


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            m5ui.deinit()
            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.

MQTT Example

This example shows how to send MQTT message using the NBIoT2 Unit.

MicroPython Code Block:

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

import os, sys, io
import M5
from M5 import *
import m5ui
import lvgl as lv
from unit import NBIOT2Unit


page0 = None
label0 = None
nbiot2_0_mqtt = None
nbiot2_0 = None


def nbiot2_0__testtopic_a_event(data):
    global page0, label0, nbiot2_0_mqtt, nbiot2_0
    label0.set_text(str(data[1]))


def setup():
    global page0, label0, nbiot2_0_mqtt, nbiot2_0

    M5.begin()
    Widgets.setRotation(1)
    m5ui.init()
    page0 = m5ui.M5Page(bg_c=0xFFFFFF)
    label0 = m5ui.M5Label(
        "label0",
        x=130,
        y=105,
        text_c=0x000000,
        bg_c=0xFFFFFF,
        bg_opa=0,
        font=lv.font_montserrat_14,
        parent=page0,
    )

    nbiot2_0 = NBIOT2Unit(1, port=(18, 17), verbose=False)
    page0.screen_load()
    nbiot2_0.connect(apn="cmnbiot")
    while not (nbiot2_0.isconnected()):
        pass
    nbiot2_0_mqtt = nbiot2_0.MQTTClient(
        "uiflow2-client", "mqtt.m5stack.com", port=1883, user="", password="", keepalive=0
    )
    nbiot2_0_mqtt.connect(clean_session=False)
    nbiot2_0_mqtt.subscribe("testtopic/a", nbiot2_0__testtopic_a_event, qos=0)


def loop():
    global page0, label0, nbiot2_0_mqtt, nbiot2_0
    M5.update()
    nbiot2_0_mqtt.check_msg()


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            m5ui.deinit()
            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

NBIOT2Unit

class unit.nbiot2.NBIOT2Unit(id=1, port=None, verbose=False)

Bases: SIM7028

Create an NBIOT2Unit object.

Parameters:

id (int) – The UART ID.
port (list | tuple) – A list or tuple containing the RX and TX pin numbers.
verbose (bool) – Whether to print debug information.

UiFlow2 Code Block:

MicroPython Code Block:

from unit import NBIOT2Unit

# Using UART ID 1 and pins (rx=16, tx=17)
nbiot2 = NBIOT2Unit(1, port=(16, 17))

Note

See NBIOTUnit for more details.