Add rp2040 publish/sub example for guide

examples/adafruit_io_mqtt/adafruit_io_pubsub_rp2040.py

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+# SPDX-FileCopyrightText: Brent Rubell for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import time
+from microcontroller import cpu
+import board
+import busio
+from digitalio import DigitalInOut
+from adafruit_esp32spi import adafruit_esp32spi
+from adafruit_esp32spi import adafruit_esp32spi_wifimanager
+import adafruit_esp32spi.adafruit_esp32spi_socket as socket
+import adafruit_minimqtt.adafruit_minimqtt as MQTT
+from adafruit_io.adafruit_io import IO_MQTT
+
+### WiFi ###
+
+# Get wifi details and more from a secrets.py file
+try:
+    from secrets import secrets
+except ImportError:
+    print("WiFi secrets are kept in secrets.py, please add them there!")
+    raise
+
+# Raspberry Pi RP2040
+esp32_cs = DigitalInOut(board.GP13)
+esp32_ready = DigitalInOut(board.GP14)
+esp32_reset = DigitalInOut(board.GP15)
+
+spi = busio.SPI(board.GP10, board.GP11, board.GP12)
+esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)
+
+wifi = adafruit_esp32spi_wifimanager.ESPSPI_WiFiManager(esp, secrets)
+
+# Configure the RP2040 Pico LED Pin as an output
+led_pin = DigitalInOut(board.LED)
+led_pin.switch_to_output()
+
+# Define callback functions which will be called when certain events happen.
+# pylint: disable=unused-argument
+def connected(client):
+    # Connected function will be called when the client is connected to Adafruit IO.
+    print("Connected to Adafruit IO! ")
+
+
+def subscribe(client, userdata, topic, granted_qos):
+    # This method is called when the client subscribes to a new feed.
+    print("Subscribed to {0} with QOS level {1}".format(topic, granted_qos))
+
+
+# pylint: disable=unused-argument
+def disconnected(client):
+    # Disconnected function will be called when the client disconnects.
+    print("Disconnected from Adafruit IO!")
+
+
+def on_led_msg(client, topic, message):
+    # Method called whenever user/feeds/led has a new value
+    print("New message on topic {0}: {1} ".format(topic, message))
+    if message == "ON":
+        led_pin.value = True
+    elif message == "OFF":
+        led_pin.value = False
+    else:
+        print("Unexpected message on LED feed.")
+
+
+# Connect to WiFi
+print("Connecting to WiFi...")
+wifi.connect()
+print("Connected!")
+
+# Initialize MQTT interface with the esp interface
+MQTT.set_socket(socket, esp)
+
+# Initialize a new MQTT Client object
+mqtt_client = MQTT.MQTT(
+    broker="io.adafruit.com",
+    username=secrets["aio_username"],
+    password=secrets["aio_key"],
+)
+
+# Initialize an Adafruit IO MQTT Client
+io = IO_MQTT(mqtt_client)
+
+# Connect the callback methods defined above to Adafruit IO
+io.on_connect = connected
+io.on_disconnect = disconnected
+io.on_subscribe = subscribe
+
+# Set up a callback for the led feed
+io.add_feed_callback("led", on_led_msg)
+
+# Connect to Adafruit IO
+print("Connecting to Adafruit IO...")
+io.connect()
+
+# Subscribe to all messages on the led feed
+io.subscribe("led")
+
+prv_refresh_time = 0.0
+while True:
+    # Poll for incoming messages
+    try:
+        io.loop()
+    except (ValueError, RuntimeError) as e:
+        print("Failed to get data, retrying\n", e)
+        wifi.reset()
+        io.reconnect()
+        continue
+    # Send a new temperature reading to IO every 30 seconds
+    if (time.monotonic() - prv_refresh_time) > 30:
+        # take the cpu's temperature
+        cpu_temp = cpu.temperature
+        # truncate to two decimal points
+        cpu_temp = str(cpu_temp)[:5]
+        print("CPU temperature is %s degrees C" % cpu_temp)
+        # publish it to io
+        print("Publishing %s to temperature feed..." % cpu_temp)
+        io.publish("temperature", cpu_temp)
+        print("Published!")
+        prv_refresh_time = time.monotonic()