Adafruit Metro M4 Express (ATSAMD51)

Overview

The Adafruit Metro M4 Express is a significant upgrade over the Metro M0, featuring the Microchip ATSAMD51J19 ARM Cortex-M4 with FPU running at 120 MHz. With 512KB of flash, 192KB of SRAM, and 2MB of QSPI flash for CircuitPython file storage, it has ample resources for sophisticated applications.

The ATSAMD51 brings hardware acceleration that the M0 lacks: AES-256 encryption, a true hardware random number generator, and a public key cryptography accelerator — useful for secure IoT applications. Six configurable hardware SERCOM modules provide flexible I2C, SPI, or UART assignments, and stereo I2S input/output with a dedicated MCK pin enables high-quality audio applications.

Two 12-bit DACs (1 MSPS each) and dual 12-bit ADCs (also 1 MSPS) make this an excellent platform for audio and signal processing. A built-in NeoPixel LED, 22 PWM outputs, and a 10-bit parallel capture controller for camera interfacing round out the feature set.

The Metro M4 Express uses the standard Arduino shield form factor, making it compatible with the vast library of Arduino shields. It is fully supported by CircuitPython, Adafruit's Python implementation, and the full Arduino IDE ecosystem.