CircuitPython Wi-Fi + Ethernet with PoE

code.py

# SPDX-FileCopyrightText: 2025 anecdata
# SPDX-License-Identifier: MIT

# Pimoroni Pico Plus 2W
# connected via Adafruit Proto Doubler PiCowbell to
# WIZnet W5500-EVB-Pico2 with WIZPOE-P1
# https://fosstodon.org/@anecdata/115115735846073971
# code is a simplified version of https://gist.github.com/anecdata/456524f8e38c207931afd0dedf6bec89

import time
import os
import traceback
import board
import busio
import digitalio
import wifi
import ssl
import adafruit_connection_manager
import adafruit_requests
from adafruit_wiznet5k.adafruit_wiznet5k import WIZNET5K


URLS = (
    "http://wifitest.adafruit.com/testwifi/index.html",
    "https://httpbin.org/get",
)

# wifi (native)

def connect_native(radio):
    while not radio.connected:
        try:
            radio.connect(os.getenv("WIFI_SSID"), os.getenv("WIFI_PASSWORD"))
        except Exception as ex:
            traceback.print_exception(ex, ex, ex.__traceback__)
            time.sleep(1)
    return radio.ipv4_address

# WIZnet

wiz_pins = (
    (
        digitalio.DigitalInOut(board.GP17),
        digitalio.DigitalInOut(board.GP20),
    ),
)

def connect_eth(radio):
    return radio.pretty_ip(radio.ip_address)

# General

def connect(radio):
    if radio.__class__.__name__ == "Radio":
        ipv4_str = connect_native(radio)
    elif radio.__class__.__name__ == "WIZNET5K":
        ipv4_str = connect_eth(radio)
    elif radio.__class__.__name__ == "ESP_SPIcontrol":
        ipv4_str = connect_esp(radio)
    return ipv4_str


time.sleep(3)  # wait for serial

# LED
led = digitalio.DigitalInOut(board.LED)
led.switch_to_output(value=False)

radios = []
pools = []
ssl_contexts = []
requestss = []
connection_managers = []


# spi = board.SPI()
spi = busio.SPI(clock=board.GP18, MOSI=board.GP19, MISO=board.GP16)

# wifi (native)
print(f'Initializing native wifi...')
radios.append(wifi.radio)

# WIZnet
print(f'Initializing ethernets...')
for eth in range(0, len(wiz_pins)):
    print(f'#{eth}')
    cs = wiz_pins[eth][0]
    rst = wiz_pins[eth][1]
    mac = f'de:ad:be:ef:fe:{(251 + eth):02x}'  # avoid DHCP collisions
    while True:
        try:
            radio = WIZNET5K(spi, cs, rst, mac=mac, debug=False)
            print(f'{mac} {radio.pretty_ip(radio.ip_address)}')
            radios.append(radio)
            break
        except Exception as ex:
            traceback.print_exception(ex, ex, ex.__traceback__)

# set up the socketpools and requests
print(f'Set up socketpools and requests...')
for radio_num in range(0, len(radios)):
    pools.append(adafruit_connection_manager.get_radio_socketpool(radios[radio_num]))
    ssl_contexts.append(adafruit_connection_manager.get_radio_ssl_context(radios[radio_num]))
    requestss.append(adafruit_requests.Session(pools[radio_num], ssl_contexts[radio_num]))
    connection_managers.append(adafruit_connection_manager.get_connection_manager(pools[radio_num]))

# requests on all the radios
while True:
    print(f'{"="*25}')
    for radio_num in range(0, len(radios)):
        print(f'{"-"*25}')
        for url in URLS:
            print(f"Fetching from {url} via {radios[radio_num].__class__.__name__} #{radio_num} {pools[radio_num]} {connection_managers[radio_num]}")
            print(f"{connect(radios[radio_num])}")
            try:
                with requestss[radio_num].get(url) as resp:
                    print(f'{resp.status_code} {resp.reason.decode()}')
            except Exception as ex:
                traceback.print_exception(ex, ex, ex.__traceback__)
            led.value = not led.value
            time.sleep(1)

This code is running independently on the WIZnet W5500-EVB-Pico2:

import time
import board
import digitalio

time.sleep(3)  # wait for serial after reset

# LED
led = digitalio.DigitalInOut(board.LED)
led.switch_to_output(value=False)

while True:
    led.value = not led.value
    time.sleep(1)

Power over Ethernet supplies power to both microcontrollers. One or both USB connections can be made to a host to edit code, view serial output, etc.

dual-code.mov

🔌 USB power on both boards is protected with a Schottky diode upstream of VSYS. PoE power is similarly protected with a Schottky diode upstream of VSYS. I've left the 3V3 pins unconnected between the two boards, to keep the two LDO outputs separate. I've also left the VBUS (5V) pins unconnected between the two boards. If any of the three power sources are connected (PoE, or either USB-C), both boards will be powered via VSYS.