Adafruit (PID 2010 Pro Trinket - 3V 12MHz

Trinket's a year old now, and while its been great to see tons of tiny projects, sometimes you just need more pins, more FLASH, and more RAM. That's why we designed Pro Trinket, with 18 GPIO, 2 extra analog inputs, 28K of flash, and 2K of RAM.

It has onboard USB bootloading support - we opted for a MicroUSB jack this time. We also added Optiboot support, so you can either program your Pro Trinket over USB or with a FTDI cable just like the Pro Mini and friends.

The Pro Trinket PCB measures only 1.5" x 0.7" x 0.2" (without headers) but packs the same capability as an Arduino UNO.

The Pro Trinket 3V uses the Atmega328P chip, which is the same core chip in the Arduino UNO/Duemilanove/Mini/etc. However, it uses 3V logic and 12MHz clock. Pro Trinket is programmable using the Arduino IDE as you already set up, and 95% of Arduino projects will work out of the box!

Here's some things you may have to consider when adapting Arduino sketches:

Pins #2 and #7 are not available (they are exclusively for USB)

The Pro Trinket 3V runs at 12MHz, this doesn't affect most projects. Only the most timing-specific libraries may be affected, check the documentation! The NeoPixel Library works fine at 12MHz.

The onboard power supply is a 3.3V regulator and it can provide 150mA output

You cannot plug shields directly into the Pro Trinket

There is no Serial-to-USB chip onboard. This is to keep the Pro Trinket small and inexpensive, you can use any FTDI cable to connect to the FTDI port for a Serial connection. The USB connection is for uploading new code only.

The bootloader on the Pro Trinket use 4KB of FLASH so the maximum sketch size is 28,672 bytes. The bootloader does not affect RAM usage.