The avrdude.conf and hardware/ resources come directly from the Adafruit Trinket tutorial here:
http://learn.adafruit.com/introducing-trinket
The 10-USBtiny.rules udev rules is suggested by a page linked from the tutorial
but the page is out of date and shows deprecated (pre-2009) SYSFS{...} syntax
instead of the current ATTR{...}/ATTRS{...} udev syntax.
This setup still does not work directly from the Arduino IDE. Attempting to upload directly from the IDE results in a cleared firmware (preserved bootloader, thankfully) followed by a series of errors. Programming must be done separately using avrdude commmands like this:
# Clears program space; fails with lots of errors
avrdude -c usbtiny -p attiny85 -U flash:w:trinketblink.hex
# Succeeds in programming chip (usually)
avrdude -c usbtiny -p attiny85 -D -U flash:w:trinketblink.hexThis appears to be a problem with the erase timing (something the Adafruit
provided avrdude.conf is specifically trying to address). The -D in the
second command skips the erase phase (the only part of the first command that
will succeed).
Programming must be done from the commandline using the above commands. I don't see a way to use the Ardquino IDE for more than compile. If using the Arduino IDE for compiling, the output files will be left somewhere like this (i.e. use instead of "trinketblink.hex" in the above):
/tmp/build2960098601916446287.tmp/feeder_sketch.cpp.hex
One thing further. At the time of this commit, the trinket tutorial provides links to a Linux avr ld linker that is actually the Mac OS X avr ld. (i.e. The ones provided for Linux and Mac have the same sha1sums and are Mach-o fat binaries.) The modified ld is provided to handler larger sized object files.
For now the program size is small enough not to warrant an updated linker so we skip the Adafruit suggested ld.
This project also leverages the PowerSwitch Tail II device. Documentation can be found here: