Setting My ATtiny85 Fuses To Mimic The Adafruit Trinket

September 04, 2015

To get a Adafruit Trinket Arduino sketch running on a straight-up ATtiny85, I did the following:

I set the fuses of the ATtiny85 to what I believe the Trinket uses - or at least what the boards.txt has in it. I did this using my AVR Dragon - I believe that this has to be done with high-voltage programing, but I'm not sure, so don't quote me.

avrdude -c dragon_hvsp -p attiny85 -U lfuse:w:0xc1:m -U hfuse:w:0xd4:m -U efuse:w:0xff:m -P usb

Downloaded the arduino-tiny library from their expiring Google Code site. If this gets shutdown, there may or may not be a self-hosted mirror link in the HTML comments of this page. Follow the instructions on arduino-tiny site, but essentially it required creating a boards.txt file.

To this boards.txt file, (in my case it was at ~/Documents/Arduino/hardware/tiny/avr/boards.txt) I added the following:

###########################################################################

attiny85at16p.name=ATtiny85 @ 16 MHz  (internal PLL; 4.3 V BOD)

attiny85at16p.upload.tool=arduino:arduinoisp

attiny85at16p.upload.maximum_size=8192
attiny85at16p.upload.maximum_data_size=512

# PLL Clock; Start-up time PWRDWN/RESET: 1K CK/14 CK + 4 ms; [CKSEL=0001 SUT=00]
# Brown-out detection level at VCC=4.3 V; [BODLEVEL=100]
# Preserve EEPROM memory through the Chip Erase cycle; [EESAVE=0]
# Serial program downloading (SPI) enabled; [SPIEN=0]

attiny85at16p.bootloader.low_fuses=0xC1
attiny85at16p.bootloader.high_fuses=0xD4
attiny85at16p.bootloader.extended_fuses=0xFF

attiny85at16p.bootloader.path=empty
attiny85at16p.bootloader.file=empty85at16.hex
attiny85at16p.bootloader.tool=arduino:avrdude

attiny85at16p.build.mcu=attiny85
attiny85at16p.build.f_cpu=16000000L
attiny85at16p.build.core=tiny

Now, obviously, select this board when building the sketch.