Adafruit Feather M4 Express

Overview

The Adafruit Feather M4 Express is the high-performance member of the Feather family, powered by the Microchip ATSAMD51J19 ARM Cortex M4F processor at 120 MHz with hardware floating-point. It offers a significant performance uplift over M0-based Feathers while maintaining the standard Feather form factor and full compatibility with the extensive FeatherWing ecosystem.

With 512 KB of internal flash, 192 KB of SRAM, and 2 MB of external SPI flash, the Feather M4 has ample storage for complex CircuitPython scripts, audio samples, and data buffers. The ATSAMD51J19 includes 6 hardware SERCOM units (configurable as SPI, I2C, or Serial), dual 1 MSPS 12-bit DAC outputs, dual 1 MSPS 12-bit ADC, I2S stereo audio, 8-bit parallel capture, and 16 PWM outputs. AES-256 hardware acceleration and a true RNG provide cryptographic capability for secure IoT applications.

Native USB handles HID, MIDI, CDC serial, and mass storage modes simultaneously. The UF2 bootloader enables drag-and-drop firmware flashing: plugging in the board mounts it as a USB drive where .uf2 files or CircuitPython .py files can be copied directly. A built-in NeoPixel and a red LED provide visual feedback. The JST LiPo connector with built-in 100mA charger makes battery-powered deployments straightforward.

The Feather M4 is ideal for audio synthesis, software-defined radio preprocessing, machine learning inference on small models, real-time data visualization, and any maker project that needs more processing power than an M0 can provide without sacrificing the convenient Feather form factor.