Anyone know if the ATtiny84 is supported?
I assumed it was a 16 pin version of the ATtiny85, but I don't think it has a high frequency PLL. Also I don't know if it possible to use it with an external crystal since the RESET/D-/INT0 are all taken up.
Is the ATtiny84 supported?
The Tiny84 SHOULD work, but I have not yet tested it myself.
Since there is no PLL clock, you need an external crystal. This makes pin assignment a bit tricky, as you already noticed.
You have the following options:
(1) Use Port A for D+ and D- and connect INT0 to D+, too. You lose one I/O pin with this approach.
(2) You use a different interrupt instead of INT0, e.g. PCINT0. You must make your own interrupt configuration values in this case, see the end of usbconfig-prototype.h for more info.
(3) Use high voltage serial programming and disable the RESET pin.
Since there is no PLL clock, you need an external crystal. This makes pin assignment a bit tricky, as you already noticed.
You have the following options:
(1) Use Port A for D+ and D- and connect INT0 to D+, too. You lose one I/O pin with this approach.
(2) You use a different interrupt instead of INT0, e.g. PCINT0. You must make your own interrupt configuration values in this case, see the end of usbconfig-prototype.h for more info.
(3) Use high voltage serial programming and disable the RESET pin.