o 22 GPIO pins: 9 analog inputs, 21 PWM, 2 serial, 3 SPI, 3 I2C
o All GPIO is 3.3V but 5 volt tolerant
o 2 rows of 9 0.1" pins, with a third 0.05" row of 8 pins on the end
o On-board USB "PCB Type" connector, plugs right into any computer USB port
o Two on-board LEDs and one button
o STM32F401CDU6 CPU - ARM Cortex
o On-board 3.3v 250mA voltage regulator, accepts voltages from 3.5v to 16v
o Current draw in sleep: < 0.05mA - over 2.5 years on a 2500mAh battery
o On-board FET can be used to drive high-current outputs