Adafruit Metro M4 Express AirLift (WiFi) - Lite

Metro M4 development board with Microchip ATSAMD51 at 120 MHz and an on-board ESP32 WiFi co-processor with pre-loaded TLS root certificates.

USB
Micro USB power/data connection; Adafruit states it is one primary way to power the Metro M4 Express AirLift.
Type · powerVoltage · USB 5V input, fused; guide states up to about 500mA across Vin/5V/3.3V supplies combined
DC jack
5.5mm/2.1mm centre-positive DC input jack; Adafruit states it is the other primary power input.
Type · powerVoltage · 6V-12V input stated by Adafruit guide
VIN
Board VIN supply rail available on the Metro header, tied to external input power path per pinouts guide power section.
Type · power
5V
5V board supply rail exposed on the Metro header.
Type · powerVoltage · 5V
3.3V
Regulated 3.3V board supply rail exposed on the Metro header.
Type · powerVoltage · 3.3V

Start wiring

USB · 3.3 V

Confirm the data interface matches your host board.

Module pins: USB, DC jack, VIN, 5V, 3.3V, GND, #0 / RX, #1 / TX. Schematik maps them to your board in the app.

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Position

Type

Function

Voltage

USB

power

Micro USB power/data connection; Adafruit states it is one primary way to power the Metro M4 Express AirLift.

USB 5V input, fused; guide states up to about 500mA across Vin/5V/3.3V supplies combined

DC jack

power

5.5mm/2.1mm centre-positive DC input jack; Adafruit states it is the other primary power input.

6V-12V input stated by Adafruit guide

VIN

power

Board VIN supply rail available on the Metro header, tied to external input power path per pinouts guide power section.

power

5V board supply rail exposed on the Metro header.

3.3V

power

Regulated 3.3V board supply rail exposed on the Metro header.

3.3V

GND

ground

Ground pins on the Metro headers.

#0 / RX

signal

GPIO #0, receive input for Serial1 hardware UART, per Adafruit pinouts guide.

3.3V logic

#1 / TX

signal

GPIO #1, transmit output for Serial1 hardware UART, per Adafruit pinouts guide.

3.3V logic

#2-#12

signal

General-purpose digital GPIO pins; guide states all logic pins are 3.3V and interrupt-capable.

3.3V logic

#13 / L

signal

GPIO #13, connected to the red LED marked L next to the USB jack.

3.3V logic

SDA

signal

I2C/Wire data pin on the Metro header.

3.3V logic

SCL

signal

I2C/Wire clock pin on the Metro header; guide notes SCL is the exception to PWM availability.

3.3V logic

A0-A5

signal

Analogue-capable header pins; A0 has true analogue output per Adafruit pinouts guide.

3.3V logic/analogue domain

SPI

signal

SPI bus exposed for board peripherals and header use; ESP32 AirLift uses SPI data plus dedicated control pins.

3.3V logic

ESP_CS / SPIWIFI_SS / 36

signal

ESP32 AirLift chip-select pin for WiFi SPI interface, named by Adafruit guide.

3.3V logic

ESP_BUSY / SPIWIFI_ACK / 37

signal

ESP32 AirLift ready/busy acknowledgement pin, named by Adafruit guide.

3.3V logic

ESP_RESET / SPIWIFI_RESET / 38

signal

ESP32 AirLift reset pin, named by Adafruit guide.

3.3V logic

ESP_RX / ESP_TX

signal

Dedicated UART between the main MCU and ESP32 AirLift; guide states it is separate from the Metro RX/TX breakout pins.

3.3V logic

ESP_RTS / 34

signal

ESP32 RTS pin exposed for advanced serial contexts, per Adafruit guide.

3.3V logic

ESP_GPIO0 / 35

signal

ESP32 GPIO0 bootloader-enable pin, per Adafruit guide.

3.3V logic

Pinout

Start wiring

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