Check out the product description below for more information. This particular model, the Adafruit FT232H is capable of working in USB to SPI, I2C and most importantly, for me anyway, GPIO mode. What can I say about this little board, it’s FANTASTIC!! All the fun of GPIO without having to purchase and hook up a Raspberry Pi and there is also fantastic support for C# what else could you need.
Reset button for entering the bootloader or restarting the program.Adafruit FT232H Breakout – General Purpose USB to GPIO+SPI+I2C.On-board green power LED and red pin #13 LED.Power with either USB or external output (such as a battery) - it'll automatically switch over.Up to 16V input, reverse-polarity protection, thermal and current-limit protection. On-board 5.0V power regulator with 150mA output capability and ultra-low dropout.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.Also has headers for an FTDI port for reprogramming.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).The bootloader does not affect RAM usage.
The USB connection is for uploading new code only.
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.
Trinket's got a big sister in town - the Pro Trinket 5V! Pro Trinket combines everything you love about Trinket with the familiarity of the common core Arduino chip, the ATmega328.