Is the ATtiny84 supported?

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
Post Reply

Is the ATtiny84 supported?

Post by theduder » Wed Jan 16, 2008 4:58 am

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.

Objective Development
Objective Development
Posts: 1443
Joined: Thu Nov 09, 2006 11:46 am

Post by christian » Mon Jan 21, 2008 7:48 pm

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.

Post Reply