Adafruit ItsyBitsy 32u4 - 5V 16MHz
➤ ATmega32u4 onboard chip in QFN package
➤ 5V power and logic, 16MHz clock rate, 2KB RAM and 28K FLASH
➤ USB bootloader with a nice LED indicator, AVR109 compatible (same as Flora, Feather 32u4, Leonardo, etc)
➤ Micro-USB jack for power, USB uploading and debugging, you can put it in a box or tape it up and use any Micro USB cable for when you want to reprogram.
➤ Can act as a USB HID Keyboard, Mouse, MIDI or plain USB 'CDC' serial device (default)
➤ Onboard 5.0V power regulator with 150mA output capability and ultra-low dropout. Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
➤ Low current 3.3V regulator output from the chip, for small sensors
➤ Power with either USB or external output (such as a battery) into VBAT pin - it'll automatically switch over
➤ On-board red pin #13 LED
➤ 23 GPIO total - 6 analogs in, 1x SPI port, 1x I2C port, 1x Hardware Serial port, and 10 more GPIO, 4 of which have PWM
➤ Can drive NeoPixels, connect to sensors, servos, etc.
➤ Reset button for entering the bootloader or restarting the program.
➤ Product Dimensions: 35.0mm x 18.0mm x 4.1mm / 1.4" x 0.7" x 0.2"
➤ Product Weight: 2.6g / 0.1oz