If you like the Adafruit Trinket but need just a little bit more from your micro, the Pro Trinket is the answer. Sometimes you just need more pins, more FLASH, and more RAM. that's exactly what you get with the Adafruit Pro Trinket, featuring 18 GPIO, 2 extra analog inputs, 28K of flash, and 2K of RAM.
Pro Trinket combines everything you love about Trinket with the familiarity of the common core Arduino chip, the ATmega328. It's like an Arduino Pro Mini with more pins and complete with USB. Like the Trinket, it has onboard USB bootloading support (MicroUSB this time though). Optiboot support, means 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 40 x 18 x 5mm (without headers) but packs much of the same capability as an Arduino UNO!
The Pro Trinket 5V uses the Atmega328P chip, which is the same core chip in the Arduino UNO/Duemilanove/Mini/etc. at the same speed and voltage. So you'll be happy to hear that not only is Pro Trinket programmable using the Arduino IDE as you already set up, but 99% of Arduino projects will work out of the box!
- ATmega328P onboad chip in QFN package
- 16MHz clock rate, 28K FLASH
- USB bootloader with a nice LED indicator looks just like a USBtinyISP so you can program it with AVRdude and/or the Arduino IDE (with a few simple config modifications).
- Also has headers for an FTDI port for reprogramming
- Micro-USB jack for power and/or USB uploading, you can put it in a box or tape it up and use any USB cable for when you want to reprogram.
- On-board 5.0V power regulator with 150mA output capability and ultra-low dropout. Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
- Power with either USB or external output (such as a battery) - it'll automatically switch over
- On-board green power LED and red pin #13 LED
- Reset button for entering the bootloader or restarting the program.
- Works with 99% of existing Arduino sketches (anything that doesn't use more than 28K, and doesn't require pins #2 and #7)
- Mounting holes!