Adafruit ItsyBitsy nRF52840 Express

Overview

The Adafruit ItsyBitsy nRF52840 Express packs a remarkably capable wireless microcontroller into one of the smallest form factors in Adafruit's lineup. Measuring just 36.0×17.6mm — small enough to fit on a half-size breadboard — it uses the Nordic Semiconductor nRF52840 ARM Cortex-M4F running at 64MHz, the same chip found in the larger Feather nRF52840 boards but shrunk to ItsyBitsy dimensions.

The nRF52840's integrated 2.4GHz radio provides Bluetooth 5.0 BLE with +8dBm output power, enabling reliable wireless communication with smartphones, computers, and other BLE peripherals. Internal memory is generous for an embedded board: 1024KB of Flash and 256KB of RAM onboard, supplemented by 2MB of QSPI Flash for storing CircuitPython scripts, sound files, and other assets. Native USB support (no UART chip required) allows the board to act as a serial port, HID keyboard, mouse, joystick, or MIDI device.

Twenty-one GPIO pins support 6 analog inputs, up to 12 PWM outputs, hardware SPI, UART, I2C, and I2S — all on any pin via the nRF52840's flexible routing. A special Vhigh pin outputs the USB rail voltage for driving 5V-logic peripherals. A red LED and a mini DotStar RGB LED provide status feedback.

The board ships with the UF2 bootloader pre-loaded, enabling drag-and-drop firmware updates over USB without any special programmer. It carries FCC, IC, and TELEC certifications and is compatible with both the Arduino IDE (with Adafruit's nRF52 board package) and CircuitPython.