When using a MatrixPortal with CircuitPython, “publish” will intermittently hang indefinitely without returning any error messages rendering the M4 unresponsive.

This is documented in Adafruit Forums.

please include minimal code that reliably demonstrates the issue

Hello,

I also seem to have this issue. After an MQTT publish the code seems to hang with no error. This can be within a few hours upto a day or two. ` import time import board import busio #import adafruit_shtc3 import adafruit_sht4x from digitalio import DigitalInOut, Direction, Pull from adafruit_pm25.i2c import PM25_I2C

#NTP import ipaddress import ssl import wifi import socketpool import adafruit_requests import secrets import rtc

#MQTT import adafruit_minimqtt.adafruit_minimqtt as MQTT

#Binary to HEX from adafruit_binascii import hexlify, unhexlify

#Continuity import supervisor import microcontroller

try: from secrets import secrets except ImportError: print("WiFi secrets are kept in secrets.py, please add them there!") raise print("Starting AQ monitor...") #Get unique ID based on MAC address ID = hexlify(wifi.radio.mac_address) ID = str(ID,'utf-8')

If you have a GPIO, its not a bad idea to connect it to the RESET pin

reset_pin = DigitalInOut(board.IO6) reset_pin.direction = Direction.OUTPUT reset_pin.value = False

MQTT Topic

Use this topic if you'd like to connect to a standard MQTT broker

mqtt_topic = "LOG/"+ ID +"/DATA"

Get our username, key and desired timezone

aio_username = secrets["aio_username"] aio_key = secrets["aio_key"] location = secrets.get("timezone", None) TIME_URL = "https://io.adafruit.com/api/v2/%s/integrations/time/strftime?x-aio-key=%s" % (aio_username, aio_key) TIME_URL += "&fmt=%25Y-%25m-%25d+%25H%3A%25M%3A%25S.%25L+%25j+%25u+%25z+%25Z"

print("MAC ID addr:", ID)

print("Connecting to %s"%secrets["ssid"]) wifi.radio.connect(secrets["ssid"], secrets["password"]) print("Connected to %s!"%secrets["ssid"]) print("My IP address is", wifi.radio.ipv4_address) print("Getting Time...")

radio = wifi.radio pool = socketpool.SocketPool(radio) requests = adafruit_requests.Session(pool, ssl.create_default_context()) response = requests.get("http://worldtimeapi.org/api/timezone/Etc/UTC") if response.status_code == 200: r = rtc.RTC() r.datetime = time.localtime(response.json()['unixtime']) print(f"System Time: {r.datetime}") else: print("Setting time failed") #supervisor.reload() microcontroller.reset()

Code

Define callback methods which are called when events occur

pylint: disable=unused-argument, redefined-outer-name

def connect(mqtt_client, userdata, flags, rc): # This function will be called when the mqtt_client is connected # successfully to the broker. print("Connected to MQTT Broker!") print("Flags: {0}\n RC: {1}".format(flags, rc))

def disconnect(mqtt_client, userdata, rc): # This method is called when the mqtt_client disconnects # from the broker. print("Disconnected from MQTT Broker!")

def subscribe(mqtt_client, userdata, topic, granted_qos): # This method is called when the mqtt_client subscribes to a new feed. print("Subscribed to {0} with QOS level {1}".format(topic, granted_qos))

def unsubscribe(mqtt_client, userdata, topic, pid): # This method is called when the mqtt_client unsubscribes from a feed. print("Unsubscribed from {0} with PID {1}".format(topic, pid))

def publish(mqtt_client, userdata, topic, pid): # This method is called when the mqtt_client publishes data to a feed. print("Published to {0} with PID {1}".format(topic, pid))

def message(client, topic, message): # Method called when a client's subscribed feed has a new value. print("New message on topic {0}: {1}".format(topic, message))

Create a socket pool

pool = socketpool.SocketPool(wifi.radio)

Set up a MiniMQTT Client

mqtt_client = MQTT.MQTT( broker= 'IPADDRESS', port= PORT, #username=secrets["aio_username"], #password=secrets["aio_key"], socket_pool=pool, ssl_context=ssl.create_default_context(), )

Connect callback handlers to mqtt_client

mqtt_client.on_connect = connect mqtt_client.on_disconnect = disconnect mqtt_client.on_subscribe = subscribe mqtt_client.on_unsubscribe = unsubscribe mqtt_client.on_publish = publish mqtt_client.on_message = message

Create library object, use 'slow' 100KHz frequency!

HTi2c = board.I2C() #SHTC3 sensor #sht = adafruit_shtc3.SHTC3(HTi2c) #SHT4 sensor sht = adafruit_sht4x.SHT4x(HTi2c) #Breadboard Wired header pins #PMi2c = busio.I2C(board.IO1, board.IO38, frequency=100000) PMi2c = board.I2C()

Connect to a PM2.5 sensor over I2C

pm25 = PM25_I2C(PMi2c, reset_pin)

print("Found PM2.5 sensor, reading data...")

while True: time.sleep(59) unix = time.time()

try:
    aqdata = pm25.read()
    temperature, relative_humidity = sht.measurements
    print(aqdata)
except RuntimeError:
    print("Unable to read from sensor, retrying...")
    supervisor.reload()
    #microcontroller.reset()
try:
    # Poll the message queue
    #mqtt_client.loop()
    print("Attempting to connect to %s" % mqtt_client.broker)
    mqtt_client.connect()
    try:
        print("Subscribing to %s" % mqtt_topic)
        mqtt_client.subscribe(mqtt_topic)
    except:
        continue
    #print("Publishing to %s" % mqtt_topic)
    try:
        print(
            "%d, %d, %d, %d, %d, %d, 0"
            % (unix, temperature, relative_humidity, aqdata["pm10 env"], aqdata["pm25 env"], aqdata["pm100 env"])
        )
        mqtt_client.publish(mqtt_topic, "%d, %d, %d, %d, %d, %d, 0"
            % (unix, temperature, relative_humidity, aqdata["pm10 env"], aqdata["pm25 env"], aqdata["pm100 env"]) )
    except:
        continue
    #print("Unsubscribing from %s" % mqtt_topic)
    try:
        mqtt_client.unsubscribe(mqtt_topic)
    except:
        continue
    #print("Disconnecting from %s" % mqtt_client.broker)
    try:
        mqtt_client.disconnect()
    except:
        continue
except:
    print("Something went wrong")
    try:
        mqtt_client.reconnect()
    except:
        continue
    continue

`

The code in https://github.com/adafruit/Adafruit_CircuitPython_MiniMQTT/issues/81#issuecomment-836570883 is in dire need of reformatting - use the triple backtick to include larger chunks of code.