Raspberry Pi Pico 2 + W5500 + E22-900M30S - Meshtastic Variant

Meshtastic support for a Raspberry Pi Pico 2 (RP2350, 4 MB flash) with an external W5500 Ethernet module and an EBYTE E22-900M30S LoRa module.

Required Hardware

Component	Model	Notes
MCU	Raspberry Pi Pico 2	RP2350 @ 150 MHz, 512 KB RAM, 4 MB flash
Ethernet	W5500 module	Any WIZnet W5500 breakout board
LoRa	EBYTE E22-900M30S	SX1262 + 30 dBm PA, 868/915 MHz

Pinout

System pins (Pico 2, fixed)

GPIO	Function
GP24	VBUS sense - HIGH when USB is connected
GP25	User LED (heartbeat)
GP29	ADC3 - VSYS/3, measures supply voltage

W5500 Ethernet (SPI0)

W5500 signal	Pico 2 GPIO
MISO	GP16
CS / SCS	GP17
SCK	GP18
MOSI	GP19
RST	GP20
INT	- (nc)
VCC	3.3V
GND	GND

SPI0 is reserved for the W5500.

E22-900M30S LoRa (SPI1)

E22 signal	Pico 2 GPIO	Notes
SCK	GP10	SPI1 clock
MOSI	GP11	SPI1 TX
MISO	GP12	SPI1 RX
NSS / CS	GP13	Chip select
RESET	GP15	Active LOW reset
DIO1	GP14	IRQ interrupt
BUSY	GP2	Module busy indicator
RXEN	GP3	LNA enable - held HIGH permanently
TXEN	← DIO2	See wiring note below
VCC	3.3V	Add a 100 µF capacitor close to the module
GND	GND	-

See wiring.svg in this directory for the full connection diagram.

Special wiring: DIO2 → TXEN bridge on the E22 module

The E22-900M30S does not connect DIO2 to the TXEN pin of its PA internally. They must be bridged with a short wire or solder bridge on the module itself:

E22 DIO2 pin  ──┐
                ├── wire / solder bridge on the module
E22 TXEN pin  ──┘

With this bridge in place, SX126X_DIO2_AS_RF_SWITCH causes the SX1262 to drive DIO2 HIGH automatically during TX, enabling the PA without needing an RP2350 GPIO for TXEN.

Without this bridge the module will not transmit.

Build

pio run -e pico2_w5500_e22

Flash - BOOTSEL mode

Hold the BOOTSEL button on the Pico 2.
Connect USB to the PC - it appears as a RPI-RP2 storage drive.
Copy the .uf2 file:

.pio/build/pico2_w5500_e22/firmware-pico2_w5500_e22-*.uf2

Or directly with picotool:

pio run -e pico2_w5500_e22 -t upload

Network usage

This board uses Ethernet (no Wi-Fi). From the Meshtastic app:

Enable Ethernet under Config → Network → Ethernet Enabled
DHCP by default; static IP can also be configured

Services available once connected:

Service	Details
NTP	Time synchronization
MQTT	Messages to external broker
API	TCP socket on port 4403
Syslog	Remote logging (optional)

Technical notes

LoRa - RF control

Define	Effect
`SX126X_ANT_SW 3`	GP3 (RXEN) driven HIGH at init and never toggled again
`SX126X_DIO2_AS_RF_SWITCH`	SX1262 drives DIO2 HIGH during TX → enables TXEN via bridge
`SX126X_DIO3_TCXO_VOLTAGE 1.8`	E22 TCXO controlled by DIO3
`-D EBYTE_E22_900M30S`	Sets `TX_GAIN_LORA=7`, max power 22 dBm

RXEN and TXEN may both be HIGH simultaneously during TX - this is safe for the E22 RF switch.

Ethernet

Library: arduino-libraries/Ethernet@^2.0.2 (supports W5100/W5200/W5500 auto-detection).
SPI0 is explicitly initialized with pins GP16/18/19 before Ethernet.init().
DHCP timeout is set to 10 s (instead of the default 60 s) to avoid blocking LoRa startup.

HW_VENDOR

Mapped to meshtastic_HardwareModel_PRIVATE_HW - no dedicated model exists in the Meshtastic protobuf for this hardware combination yet.

Memory usage (reference build)

Resource	Used	Total	%
RAM	94 KB	512 KB	18%
Flash	964 KB	3.58 MB	26.3%