Adafruit ItsyBitsy 32u4 3V 8MHz

Overview

The Adafruit ItsyBitsy 32u4 3V 8MHz is an ultra-compact Arduino-compatible development board measuring just 35mm × 17mm — smaller than any Feather board yet providing the same ATmega32u4 microcontroller found in the Arduino Leonardo and Adafruit Feather 32u4 family. The 3.3V variant runs at 8 MHz, making it compatible with 3.3V sensor ecosystems and SPI Flash add-ons.

Despite its tiny footprint, the board exposes 23 GPIO pins including 6 analog inputs, 4 PWM-capable pins, hardware Serial, I2C, and SPI peripherals. The ATmega32u4's native USB is fully exposed, allowing the ItsyBitsy to appear as a USB HID keyboard, mouse, MIDI device, or CDC serial adapter — all without any host-side driver installation. The AVR109-compatible bootloader is accessible via a double-press of the reset button.

A 3.3V regulator with 500mA output handles power from up to 6V input (reverse-polarity protected), and an onboard red LED on pin 13 provides basic visual feedback. The "VHigh" pin provides a 5V logic output even from 3.3V boards, useful for driving 5V-logic peripherals like NeoPixels and servos. The ItsyBitsy 32u4 3V is ideal for downsizing prototypes originally built on Arduino Leonardo or Feather 32u4 boards into tighter enclosures.