Datasheet

Starting the Bootloader

About the bootloader

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 Trinket is that we wanted to have a built-in USB bootloader, but the ATtiny85 doesn't

have built-in USB hardware! There are existing USB bootloaders that can work on the 't85 but they use other

companies' USB VID/PIDs. Since it not permitted by the USB developer's group to use others' VID/PIDs we had to

adapt one of these existing bootloaders to use our USB ID, but we also wanted to not have to re-compile avrdude or

the Arduino IDE since that's such a pain.

So instead, Frank (our awesome engineer with mad USB chops) 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!

Trinket USB Drivers for Windows

If you're using Windows be sure to follow the Windows Driver Installation page to install the appropriate drivers for your

Trinket.

For Mac OSX or Linux you don't need to install any drivers.

Special Notes on using Trinket with Linux

Linux is fairly picky about who can poke and prod at the USB port. You can always run avrdude or Arduino IDE as root,

which will make sure you have the proper permissions. If you want to be super-cool you can add a

udev

rule which will

let any user (who is not root) connect to the USBtiny driver. That way you don't have to be root all the time!

Check http://learn.adafruit.com/usbtinyisp/avrdude#for-linux for what to add to your udev file.

How to start the bootloader

Before you try to upload code to the Trinket it must be in the Bootloader Mode. That means its listening for a sketch or

program to be sent to it

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/

Trinket is not supported on Linux operating system at this time - try Mac OS or Windows! However, you can

try the following - it does work for some computers