Datasheet

The bootloader on Pro Trinket is dual USB & FTDI "optiboot" so you can use either the

USB port or the FTDI breakout to upload. However, only the FTDI port allows you to use Serial

debugging. So it's a bit of a tradeoff - USB is inexpensive, built-in but requires a button press

to start & there's no debugging, FTDI requires an extra cable but has auto-reset and debug

console.

Select the correct Board in IDE

Make sure you're selecting the FTDI-program type in the Boards menu!

Industries

https://learn.adafruit.com/introducting-pro-trinket Page 26 of 41