Adafruit METRO M0 Express - ATSAMD21G18 Microcontroller Board

The Adafruit METRO M0 Express is a powerful microcontroller board designed for CircuitPython and Arduino IDE, featuring the ATSAMD21G18 ARM Cortex M0+ running at 48 MHz with 3.3V logic.

This board offers a significant upgrade over the original Metro 328, with 256KB of flash memory, 32KB of RAM, and built-in USB support without the need for an external serial converter chip.

• Power supply via 7-9V DC jack with on/off switch or micro USB 5V source; automatic switching between the two power inputs.
• 25 GPIO pins, including 12 analog inputs and 1 true analog output (DAC).
• Hardware support for SPI, I2C, UART, PWM outputs, and a built-in NeoPixel on pin #40.
• Onboard 2 MB SPI Flash storage usable as data storage or for CircuitPython scripts and libraries.
• Four indicator LEDs: power, RX, TX, and a red user LED on pin #13, plus an RGB NeoPixel for status indication.
• Preloaded with UF2 bootloader for easy drag-and-drop programming; compatible with CircuitPython, MakeCode, Arduino IDE, and more.
• Comes fully assembled with headers and includes 4 rubber bumpers to prevent slipping.

This board is ideal for learners and developers who want a straightforward upgrade path from classic Arduino boards to ARM Cortex M0+ microcontrollers with powerful features and convenience.

Check out our comprehensive guide for pinouts, schematics, and programming instructions.