Adafruit Metro Mini 328 V2 - Arduino-Compatible - 5V 16MHz

The Adafruit Metro Mini 328 V2 is a significant redesign of the original Metro Mini 328, packing the same ATmega328P running at 16 MHz into a compact breadboard-friendly form factor — now with USB-C and a STEMMA QT port. It's pin-compatible with Arduino UNO R3 and works with the Arduino IDE by selecting "Arduino UNO" in the Boards menu.

The V2 upgrades the USB connector to USB-C, adds a STEMMA QT / Qwiic port for plug-and-play I2C devices, and moves to the CP2102N USB-to-serial converter. Same size, same pinout, same mounting holes — just better.

What's New in V2

• USB-C – Replaces Micro USB for modern, reversible connectivity
• STEMMA QT / Qwiic Port – Solderless I2C connection for hundreds of compatible sensors and devices
• CP2102N USB-to-Serial – Upgraded from CP2104 with the same reliable drivers
• Improved 3.3V Regulator – Separate 500 mA 3.3V output

Key Features

• ATmega328P @ 16 MHz – 32 KB flash, 2 KB RAM with Optiboot bootloader
• Arduino UNO Compatible – Pin-compatible, works with Arduino IDE (desktop and cloud)
• Breadboard Friendly – Compact form factor fits standard breadboards
• 20 GPIO Pins – 6 analogue inputs, 6 PWM outputs, hardware SPI, I2C, and UART
• Built-In USB-to-Serial – SiLabs CP2102N for programming and serial communication
• 5V Logic (3.3V Optional) – Cut and solder a jumper on the bottom to switch
• Flexible Power – 6–16V on Vin pin or USB-C
• On-Board Regulators – 5V 150 mA and 3.3V 500 mA outputs
• Four Indicator LEDs – Power (green), RX/TX, and pin 13 (red)

Ideal For

• Breadboard prototyping where space is limited
• Compact Arduino UNO-compatible projects with I2C sensors
• Embedding in small enclosures and finished projects
• Upgrading from the original Metro Mini 328

Package Contents

• 1× Adafruit Metro Mini 328 V2 (fully assembled and tested)
• 1× 0.1" header strip (unsoldered)

Resources

• Optiboot Bootloader (GitHub)