Overview
Wireless is wonderful, but sometimes you want the strong reliability of a wired connection. If your project is going to be part of a permanent installation, you'll want to add ethernet networking to your project.
Ethernet is incredibly easy to use - there's no network configuration or device pairing. Just plug a standard Ethernet cable into an Ethernet FeatherWing or Ethernet Shield and use the CircuitPython Wiznet5k library for quick and reliable, networking.
- If you'd like to learn more about the Ethernet standard - check out its section in the All The Internet of Things: Transports guide.
We've built a module for CircuitPython compatible with WIZnet 5k-series TCP/IP Ethernet controllers to quickly get your projects online. Seconds after connecting, the module will handle performing the DHCP setup for you. You may also supply this module with a statically-assigned network configuration.
In this guide, you will set up your CircuitPython hardware and connect to the internet. We've included code walkthrough portions of this guide, so you can roll your own Ethernet-connected IoT CircuitPython project.
The Ethernet FeatherWing is plug-and-play compatible with CircuitPython boards which use the Feather pinout, such as the Adafruit Feather M4 Express.
The Ethernet Shield is compatible with development boards which use the pinout such as the Adafruit Metro M4 and the Adafruit Grand Central M4 Express. The shield includes a RJ45 Ethernet port and a microSD card holder for storing and reading data.
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CircuitPython Setup
CircuitPython Installation
Some CircuitPython compatible boards come with CircuitPython installed. Others are CircuitPython-ready, but need to have it installed. As well, you may want to update the version of CircuitPython already installed on your board. The steps are the same for installing and updating.
- To install (or update) your CircuitPython board, follow this page and come back here when you've successfully installed (or updated) CircuitPython.
Install the Mu Editor
This guide requires you to edit and interact with CircuitPython code. While you can use any text editor of your choosing, Mu is a simple code editor that works with the Adafruit CircuitPython boards. It's written in Python and works on Windows, MacOS, Linux and Raspberry Pi. The serial console is built right in, so you get immediate feedback from your board's serial output!
Before proceeding, if you'd like to use Mu, click the button below to install the Mu Editor. There are versions for PC, mac, and Linux.
CircuitPython Library Installation
First make sure you are running the latest version of Adafruit CircuitPython for your board.
Next you'll need to install the necessary libraries to use the hardware--carefully follow the steps to find and install these libraries from Adafruit's CircuitPython library bundle matching your version of CircuitPython. The Wiznet5k Library requires at least CircuitPython version 4.0.0.
Before continuing, make sure your board's lib folder has at least the following files and folders copied over:
- adafruit_wiznet5k
- adafruit_bus_device
- adafruit_requests.mpy
Once all the files are copied, your CIRCUITPY drive should look like the following screenshot:
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Usage
Connect Ethernet Cable
Make sure you have your Ethernet FeatherWing or Ethernet Shield firmly plugged into your hardware, and an Ethernet cable connected to your router or switch.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import adafruit_connection_manager
import adafruit_requests
import board
import busio
import digitalio
from adafruit_wiznet5k.adafruit_wiznet5k import WIZNET5K
print("Wiznet5k WebClient Test")
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_URL = "http://site.api.espn.com/apis/site/v2/sports/baseball/mlb/scoreboard"
# For Adafruit Ethernet FeatherWing
cs = digitalio.DigitalInOut(board.D10)
# For Particle Ethernet FeatherWing
# cs = digitalio.DigitalInOut(board.D5)
spi_bus = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
# Initialize ethernet interface with DHCP
eth = WIZNET5K(spi_bus, cs)
# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(eth)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(eth)
requests = adafruit_requests.Session(pool, ssl_context)
print("Chip Version:", eth.chip)
print("MAC Address:", [hex(i) for i in eth.mac_address])
print("My IP address is:", eth.pretty_ip(eth.ip_address))
print("IP lookup adafruit.com: {}".format(eth.pretty_ip(eth.get_host_by_name("adafruit.com"))))
# eth._debug = True
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print("-" * 40)
print(r.text)
print("-" * 40)
r.close()
print()
print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print("-" * 40)
print(r.json())
print("-" * 40)
r.close()
print("Done!")
Save the code.py file and open the REPL.
If you don't get an IP address, check you have a green link light, and that your Ethernet is going out to an internet connected router. You may also have to set up the MAC address to allow it access, check with your system admin if you're not sure.
In order, the example code:
Initializes the Ethernet chipset over SPI using the SPI port and the CS pin.
cs = digitalio.DigitalInOut(board.D10) spi_bus = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO) eth = WIZNET5K(spi_bus, cs)
Tells the requests library the socket, and interface we'll be using. The interface is set to an eth object. This is a little bit of a hack, but it lets us use requests like CPython does.
requests.set_socket(socket, eth)
Verifies the Ethernet hardware was found, checks the chip version and MAC address.
print("Chip Version:", eth.chip)
print("MAC Address:", [hex(i) for i in eth.mac_address])
Prints out the local IP and attempts to perform an IP address lookup for adafruit.com.
print("My IP address is:", eth.pretty_ip(eth.ip_address))
print("IP lookup adafruit.com: %s" %eth.pretty_ip(eth.get_host_by_name("adafruit.com")))
OK now we're getting to the really interesting part. With a SAMD51 or other large-RAM (well, over 32 KB) device, we can do a lot of neat tricks. Like, for example, we can implement an interface a lot like requests - which makes getting data really really easy
To read in all the text from a web URL, call requests.get -
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print('-'*40)
print(r.text)
print('-'*40)
r.close()
Or, if the data is in structured JSON, you can get the json pre-parsed into a Python dictionary that can be easily queried or traversed. (Again, only for nRF52840, M4 and other high-RAM boards)
print()
print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print('-'*40)
print(r.json())
print('-'*40)
r.close()
Manual Network Configuration
The Wiznet5k library automatically takes care of DHCP and DNS configuration, so you can get your project online quickly. However, there are cases where a network administrator will provide you with an IP address or you may need to manually configure the interface.
This code performs the same Ethernet simpletest as the above section, but allows you to configure your network interface.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import adafruit_connection_manager
import adafruit_requests
import board
import busio
import digitalio
from adafruit_wiznet5k.adafruit_wiznet5k import WIZNET5K
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
# Setup your network configuration below
IP_ADDRESS = (192, 168, 10, 1)
SUBNET_MASK = (255, 255, 0, 0)
GATEWAY_ADDRESS = (192, 168, 0, 1)
DNS_SERVER = (8, 8, 8, 8)
print("Wiznet5k WebClient Test (no DHCP)")
cs = digitalio.DigitalInOut(board.D10)
spi_bus = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
# Initialize ethernet interface without DHCP
eth = WIZNET5K(spi_bus, cs, is_dhcp=False)
# Set network configuration
eth.ifconfig = (IP_ADDRESS, SUBNET_MASK, GATEWAY_ADDRESS, DNS_SERVER)
# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(eth)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(eth)
requests = adafruit_requests.Session(pool, ssl_context)
print("Chip Version:", eth.chip)
print("MAC Address:", [hex(i) for i in eth.mac_address])
print("My IP address is:", eth.pretty_ip(eth.ip_address))
print("IP lookup adafruit.com: {}".format(eth.pretty_ip(eth.get_host_by_name("adafruit.com"))))
# eth._debug = True
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print("-" * 40)
print(r.text)
print("-" * 40)
r.close()
print()
You will need to manually set your network configuration:
-
Set
IP_ADDRESSto your desired IP address. -
Set
SUBNET_MASKto the router's subnet mask -
Set
GATEWAY_ADDRESSto the router's IP address. -
Set
DNS_SERVERto the DNS server you'd like to use. We're using 8.8.8.8 which is Google's Public DNS.
# Setup your network configuration below IP_ADDRESS = (192, 168, 10, 1) SUBNET_MASK = (255, 255, 0, 0) GATEWAY_ADDRESS = (192, 168, 0, 1) DNS_SERVER = (8, 8, 8, 8)
When the Ethernet interface is initialized, we'll disable the automatic DHCP process.
# Initialize ethernet interface without DHCP eth = WIZNET5K(spi_bus, cs, is_dhcp=False)
Then, we'll set up the network configuration by passing the ifconfig property a tuple containing the IP address, subnet mask, gateway address and DNS server.
# Set network configuration eth.ifconfig = (IP_ADDRESS, SUBNET_MASK, GATEWAY_ADDRESS, DNS_SERVER)
Troubleshooting
If you are experiencing issues, customers have found success with connecting the RESET pin of the FeatherWing to a DigitalIO pin on their Feather.
For example, for a Raspberry Pi Pico, you would declare a reset pin and then pass it to the WIZNET5K class:
... reset = digitalio.DigitalInOut(board.GP20) eth = WIZNET5K(spi_bus, cs, reset, is_dhcp=False)
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Usage with Requests
We've written a requests-like library for web interfacing named Adafruit_CircuitPython_Requests. This library allows you to send HTTP/1.1 requests without "crafting" them and provides helpful methods for parsing the response from the server.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import adafruit_connection_manager
import board
import busio
from adafruit_wiznet5k.adafruit_wiznet5k import WIZNET5K
from digitalio import DigitalInOut
import adafruit_requests
cs = DigitalInOut(board.D10)
spi_bus = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
# Initialize ethernet interface with DHCP
radio = WIZNET5K(spi_bus, cs)
# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_GET_URL = "http://httpbin.org/get"
JSON_POST_URL = "http://httpbin.org/post"
print(f"Fetching text from {TEXT_URL}")
with requests.get(TEXT_URL) as response:
print("-" * 40)
print("Text Response: ", response.text)
print("-" * 40)
print(f"Fetching JSON data from {JSON_GET_URL}")
with requests.get(JSON_GET_URL) as response:
print("-" * 40)
print("JSON Response: ", response.json())
print("-" * 40)
data = "31F"
print(f"POSTing data to {JSON_POST_URL}: {data}")
with requests.post(JSON_POST_URL, data=data) as response:
print("-" * 40)
json_resp = response.json()
# Parse out the 'data' key from json_resp dict.
print("Data received from server:", json_resp["data"])
print("-" * 40)
json_data = {"Date": "July 25, 2019"}
print(f"POSTing data to {JSON_POST_URL}: {json_data}")
with requests.post(JSON_POST_URL, json=json_data) as response:
print("-" * 40)
json_resp = response.json()
# Parse out the 'json' key from json_resp dict.
print("JSON Data received from server:", json_resp["json"])
print("-" * 40)
The code initializes a request object using a socket and the requests interface.
HTTP GET with Requests
The code makes a HTTP GET request to Adafruit's WiFi testing website - http://wifitest.adafruit.com/testwifi/index.html.
To do this, we'll pass the URL into requests.get(). We're also going to save the response from the server into a variable named response. The call to requests.get() is wrapped in a loop which retries 3 times in the event of a failed request.
While we requested data from the server, we'd like to see what the server responded with. Since we already saved the server's response, we can read it back. Luckily for us, requests automatically decodes the server's response into human-readable text. You can read it back by calling response.text.
Lastly, we'll perform a bit of cleanup by calling response.close(). This closes, deletes, and collect's the response's data.
print("Fetching text from %s"%TEXT_URL)
while not response:
try:
response = requests.get(TEXT_URL)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
print("Text Response: ", response.text)
print('-'*40)
response.close()
While some servers respond with text, some respond with json-formatted data consisting of attribute–value pairs.
CircuitPython_Requests can convert a JSON-formatted response from a server into a CPython dict object.
We can also fetch and parse json data. We'll send a HTTP get to a url we know returns a json-formatted response (instead of text data).
Then, the code calls response.json() to convert the response to a CPython dict.
print("Fetching JSON data from %s"%JSON_GET_URL)
while not response:
try:
response = requests.get(JSON_GET_URL)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
print("JSON Response: ", response.json())
print('-'*40)
response.close()
HTTP POST with Requests
Requests can also POST data to a server by calling the requests.post method, passing it a data value.
data = '31F'
print("POSTing data to {0}: {1}".format(JSON_POST_URL, data))
while not response:
try:
response = requests.post(JSON_POST_URL, data=data)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
json_resp = response.json()
# Parse out the 'data' key from json_resp dict.
print("Data received from server:", json_resp['data'])
print('-'*40)
response.close()
You can also post json-formatted data to a server by passing json_data into the requests.post method.
json_data = {"Date" : "July 25, 2019"}
print("POSTing data to {0}: {1}".format(JSON_POST_URL, json_data))
while not response:
try:
response = requests.post(JSON_POST_URL, json=json_data)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
json_resp = response.json()
# Parse out the 'json' key from json_resp dict.
print("JSON Data received from server:", json_resp['json'])
print('-'*40)
response.close()
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