Atom DTU NB IoT

Example

This program connects to an MQTT server through the NB-IoT DTU, subscribes to the topic SubTopic, and prints the topic and message content upon receiving a message. When button A is pressed, a random integer is generated and published to the topic PubTopic.

from m5stack import *
from m5ui import *
from uiflow import *
from base.DTU_NB import DTU_NB

nb_topic = None
nb_msg = None
Rand = None

import random

def nbiot_mqtt_cb(nb_mq_topic, nb_mq_payload):
  global nb_topic, nb_msg, Rand
  nb_topic = nb_mq_topic
  nb_msg = nb_mq_payload
  print(nb_topic)
  print(nb_msg)
  pass

def buttonA_wasPressed():
  global nb_topic, nb_msg, Rand
  dtu_nb.mqtt_publish('PubTopic', str(Rand), 0)
  pass
btnA.wasPressed(buttonA_wasPressed)

dtu_nb = DTU_NB()
dtu_nb.mqtt_to_connect('mqtt.m5stack.com', 1883, 'm5mqtt9', '', '', 120)
print(dtu_nb.mqtt_check_connection())
print(dtu_nb.mqtt_subscribe('SubTopic', nbiot_mqtt_cb, 0))
while True:
  if (dtu_nb.mqtt_check_connection()) != None:
    Rand = random.randint(100000, 999999)
    dtu_nb.mqtt_poll()
  wait_ms(2)

API

dtu_nb = DTU_NB()

• Initializes the NB-IoT DTU module.

modbus = dtu_nb.modbus_init(23, 33, 115200, 1, 1)

• Sets up UART communication with TX, RX pins, a baud rate of 115200, master mode, and the slave address.

modbus.function_init(1, 0, 0)

• Initializes Modbus function code for reading coil status, specifying the starting address and quantity.

modbus._mdbus_uart.any()

• Keeps the cache, possibly for storing data or other information.

dtu_nb.get_gprs_network_registration()

• Checks the GPRS network registration status, ensuring the device is connected to the network.

dtu_nb.get_network_registration()

• Checks the network registration status, confirming if the device is registered to the network.

dtu_nb.get_single_quality()

• Checks signal quality to assess the device's signal strength.

dtu_nb.check_status()

• Checks the module's status to ensure proper functioning.

dtu_nb.coap_to_connect('120.77.157.90', 5683)

• Connects using the CoAP protocol to the specified IP address and port (in this case, 120.77.157.90 and port 5683).

dtu_nb.coap_destroy()

• Destroys the CoAP connection to close or reset the CoAP session.

dtu_nb.coap_get('/m5stack-get')

• Sends a CoAP GET request to the specified URL (e.g., /m5stack-get) with no security setting.

dtu_nb.coap_post('/m5stack-post', '', content_format=0)

• Sends a CoAP POST request to the specified URL (e.g., /m5stack-post) with payload and content format as TEXT_PLAIN, no security.

dtu_nb.coap_put('/m5stack-put', '', content_format=0)

• Sends a CoAP PUT request to the specified URL (e.g., /m5stack-put) with payload and content format as TEXT_PLAIN, no security.

1-6,15-16

• Reads or sets the Modbus function code, in this case, selecting READ_COILS_STATUS as the function code.

modbus.find_address

• Retrieves the slave address.

modbus.find_function

• Retrieves the current function code.

modbus.find_quantity

• Retrieves the current quantity, possibly for reading the amount of data from the slave.

modbus.receive_req_create_pdu()

• Receives an ADU (Application Data Unit) request, used for data communication in the Modbus protocol.

modbus.create_slave_response(1)

• Sends the ADU response data in the buffer, with buffer size 1.

modbus.update_process(1, 0, 0, [0, 0, 0])

• Updates the Modbus function, currently set to READ_COILS_STATUS, specifying the start address, quantity, and updating the values list.

dtu_nb.mqtt_check_connection()

• Checks the MQTT connection status, ensuring proper connectivity with the MQTT server.

dtu_nb.mqtt_to_connect('mqtt.m5stack.com', 1883, '', '', '', 120)

• Connects to the MQTT server, specifying server address (e.g., mqtt.m5stack.com), port (default 1883), and options for client ID, username, password, and keepalive time in seconds.

dtu_nb.mqtt_disconnect()

• Disconnects from the MQTT server.

dtu_nb.mqtt_poll()

• Polls for downlink messages, checking for messages sent from the MQTT server.

dtu_nb.mqtt_publish('', '', 0)

• Publishes a topic message to the MQTT server, specifying the topic, message content (payload), and quality of service level (QoS).

dtu_nb.mqtt_subscribe('', nbiot_mqtt_cb, 0)

• Subscribes to a specified topic, with options for the topic name and quality of service level (QoS).

def nbiot_mqtt_cb(nb_mq_topic, nb_mq_payload):
  global nb_topic, nb_msg
  nb_topic = nb_mq_topic
  nb_msg = nb_mq_payload
  pass

• Sets a callback function for the subscription, which executes upon receiving a message on the specified topic. The message content is accessible via variables like nb_msg.

dtu_nb.mqtt_unsubscribe('')

• Unsubscribes from the specified topic.

dtu_nb.poweroff()

• Powers off the module to conserve energy or disable it when not needed.

modbus._mdbus_uart.read()

• Reads all relevant information or data within the module.

modbus._mdbus_uart.readline()

• Reads one line of data.

modbus._mdbus_uart.read(10)

• Reads a specified number of characters (e.g., 10 characters).

modbus.read_coils(1, 1, 0)

• Reads coil status, specifying slave address, starting address, and number of coils.

modbus.read_discrete_inputs(1, 1, 0)

• Reads discrete inputs, specifying slave address, starting address, and number of inputs.

modbus.read_holding_registers(1, 1, 0, True)

• Reads holding registers, specifying slave address, starting address, number of registers, and whether the data is signed.

modbus.read_input_registers(1, 1, 0, True)

• Reads input registers, specifying slave address, starting address, number of registers, and whether the data is signed.

dtu_nb.reset()

• Resets the module, executing the module's reset operation.

dtu_nb.set_command_echo_mode(0)

• Sets the command echo mode (e.g., enables or disables echo).

modbus._mdbus_uart.write('')

• Writes specified content to UART.

modbus._mdbus_uart.write(''+"\r\n")

• Writes a line of content to UART.

modbus.write_multiple_coils(1, 1, 0)

• Writes multiple coils, specifying

the slave address, starting address, and output values.

modbus.write_multiple_registers(1, 1, 0, True)

• Writes multiple registers, specifying the slave address, starting address, register values, and whether data is signed.

modbus._mdbus_uart.write(bytes([0, 0, 0]))

• Writes raw data to UART, with the specified data as a list of values.

modbus.write_single_coil(1, 1, 0)

• Writes a single coil, specifying the slave address, output address, and output value.

modbus.write_single_register(1, 1, 0, True)

• Writes a single register, specifying the slave address, register address, register value, and whether data is signed.