Adafruit small form factor development boards atmega328 mcu adafruit 2000 the pro trinket uses the atmega328 common core chip to give a microcontroller similar to the arduino pro mini but with usb and more pins the trinket is designed with 18x gpio pins 2x extra analog inputs 28k of flash and 2k of ram there is onboard usb bootloading support via a micro usb jack and optiboot support enable programming over usb or with a ftdi cable this 5v version operates at 16mhz and is arduino comp