Datasheet

Using the USB Bootloader

About the bootloader

A bootloader is a tiny piece of software residing on the microcontroller that that helps load

your own code into the remaining space.

One of the challenges with the Pro Trinket is that we wanted to have a built-in USB

bootloader, but the ATmega328 doesn't have built-in USB hardware!

So instead, Frank (our awesome engineer with mad USB chops) (http://adafru.it/cDX)

created a USB bootloader that combines the elegance of V-USB with the well-supported and

tested nature of the USBtinyISP. This bootloader looks just like a USBtinyISP - and since it

uses the unique Adafruit VID/PID we own and that we added to avrdude so long ago, it

works with only very minimal configuraton tweaks. No need to recompile anything, whew!

Then, since we had a little space left in the bootloader area of the chip, we added Optiboot

support. You can use either the USB connector or an FTDI cable so that it acts just like an

Arduino Uno for programming, for max flexibility.

The Pro Trinket is smart enough to auto-detect which bootloader you are trying to use. If you

plug the USB port in, it will enumerate as a USBtinyISP for USB bootloader. If you plug in FTDI

and use the Arduino Uno programming procedure it will use that technique

Pro Trinket USB Drivers for Windows

The cool thing about the bootloader on the Pro Trinket is it just looks like a classic USBtinyISP

AVR programmer. This makes it easy to use with AVRdude or Arduino IDE with only minor

configuration changes. Before you start, you may need to install the USBtinyISP USB drivers

Drivers are only required for Windows, if you are using a Mac o r Linux,

drivers are not required!

For details on installing the drivers for Windows XP, 7, 8 etc... please read this

page! (http://adafru.it/cDY)

If you're good at installing drivers, you can just download the Windows 8

drivers (http://adafru.it/djr) or Windows XP/7/Vista drivers (http://adafru.it/doK) by clicking on

those links

Please note: you cannot use the Adafruit USB VID/PID for your own non-Trinket

products or projects. Purchase a USB VID for yourself at

http://www.usb.org/developers/vendor/

Industries

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